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Sample records for igneous province emplacement

  1. Book review: Large igneous provinces

    Science.gov (United States)

    du Bray, Edward A.

    2015-01-01

    This book presents a comprehensive compilation of all aspects of large igneous provinces (LIPs). Published in 2014, the book is now the definitive source of information on the petrogenesis of this type of globally important, voluminous magmatic activity. In the first few pages, LIPs are characterized as magmatic provinces with areal extents >0.1 Mkm2 that are dominated by mafic magmas emplaced or erupted in intraplate settings during relatively short (1–5 m.y.) time intervals. Given these parameters, particularly areal extent, LIPs clearly represent significant contributions to global geologic evolution through time. This point is underscored, also in the introductory chapter, by a series of figures that aptly characterize the global time-space distribution of LIPs; an accompanying, particularly useful table identifies individual LIPs, quantifies their basic characteristics, and enumerates pertinent references. Accordingly, this compilation is a welcome addition to the geologic literature.

  2. U-Pb geochronology documents out-of-sequence emplacement of ultramafic layers in the Bushveld Igneous Complex of South Africa.

    Science.gov (United States)

    Mungall, James E; Kamo, Sandra L; McQuade, Stewart

    2016-11-14

    Layered intrusions represent part of the plumbing systems that deliver vast quantities of magma through the Earth's crust during the formation of large igneous provinces, which disrupt global ecosystems and host most of the Earth's endowment of Pt, Ni and Cr deposits. The Rustenburg Layered Suite of the enormous Bushveld Igneous Complex of South Africa has been presumed to have formed by deposition of crystals at the floor of a subterranean sea of magma several km deep and hundreds of km wide called a magma chamber. Here we show, using U-Pb isotopic dating of zircon and baddeleyite, that individual chromitite layers of the Rustenburg Layered Suite formed within a stack of discrete sheet-like intrusions emplaced and solidified as separate bodies beneath older layers. Our U-Pb ages and modelling necessitate reassessment of the genesis of layered intrusions and their ore deposits, and challenge even the venerable concept of the magma chamber itself.

  3. Unusually thickened crust beneath the Emeishan large igneous province detected by virtual deep seismic sounding

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    Liu, Zhen; Tian, Xiaobo; Chen, Yun; Xu, Tao; Bai, Zhiming; Liang, Xiaofeng; Iqbal, Javed; Xu, Yigang

    2017-11-01

    The Emeishan Large Igneous Province (ELIP) in southwest China represents the erosional remnant of a vast basalt field emplaced during the Permian Period. Spanning 0.25 million km2, the ELIP occupies a relatively small area relative to other Large Igneous Provinces (LIPs) such as the Siberian Traps and Ontong Java Plateau. The original volume of an ancient LIP can be constrained from estimates of its intrusive component. We used virtual deep seismic sounding (VDSS) to detect the boundary between the crust and the upper mantle (Moho) beneath the ELIP. A strong set of reflections from depths of 60-70 km indicate an unusually thick crust having a P-wave velocity of 7.0-7.4 km/s located beneath the inner zone of the ELIP. A high-velocity lower crustal body (HVLCB) of this thickness may have been formed by ponding magmas derived from the Emeishan mantle plume and associated fractionated materials. Combined images of crustal structure allow re-estimation of Emeishan magmatic volume. With a total estimated volume of 1.76-3.2 × 106 km3, the ELIP appears to have been a typical sized plume-generated LIP relative to other global examples.

  4. Magmatism and Eurekan deformation in the High Arctic Large Igneous Province: 40Ar–39Ar age of Kap Washington Group volcanics, North Greenland

    DEFF Research Database (Denmark)

    Tegner, Christian; Storey, Michael; Holm, Paul Martin

    2011-01-01

    The High Arctic Large Igneous Province is unusual on two counts: first, magmatism was prolonged and has been suggested to include an initial tholeiitic phase (130–80 Ma) and a second alkaline phase (85–60 Ma); second, it was subsequently deformed during the Eurekan Orogeny. New 40Ar–39Ar dating...... of alkaline volcanics from Kap Kane, part of the Kap Washington Group volcanics at the northern tip of Greenland, provides an emplacement age of 71.2±0.5 Ma obtained from amphibole in lapilli tuffs, and a thermal resetting age of 49–47 Ma obtained in feldspar and whole-rocks from trachyte flows. Patch...... in the Labrador Sea and the Baffin Bay, and to eastwards displacement of Greenland relative to North America. The alkaline suite, therefore, may be unrelated to the main tholeiitic phase of the High Arctic Large Igneous Province. The subsequent initiation of continental rifting and ensuing seafloor spreading...

  5. Lithostratigraphy and volcanology of the Serra Geral Group, Paraná-Etendeka Igneous Province in Southern Brazil: Towards a formal stratigraphical framework

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    Rossetti, Lucas; Lima, Evandro F.; Waichel, Breno L.; Hole, Malcolm J.; Simões, Matheus S.; Scherer, Claiton M. S.

    2018-04-01

    The volcanic rocks of the Lower Cretaceous Paraná-Etendeka Igneous Province, in Brazil, are grouped in the Serra Geral Group. The province can be chemically divided into low-TiO2, and high-TiO2. In southern Brazil, the low-TiO2 lava pile reaches a thickness of 1 km and is formed of heterogeneous lava packages here divided into four lava formations. Torres Formation (TF) is characterized by chemically more primitive basaltic (> 5 wt% MgO) compound pahoehoe flow fields; these lavas stratigraphically overly aeolian sandstones of Botucatu Formation and represent the onset of the volcanic activity. Vale do Sol Formation (VSF) groups vertically stacked sheet-like rubbly pahoehoe basaltic andesites (SiO2 > 51 wt%; MgO < 5 wt%). These lavas covered the former basalts in the Torres Syncline axis and pinch out towards southwest and represent the most voluminous mafic lava flows. Dacites and rhyolites of Palmas Formation (PF) overlay VSF flows in the central and eastern outcrop area and rest directly upon TF lavas in the west. The acidic units were emplaced as lava domes and widespread tabular lava flows. Esmeralda Formation (EF) is the upper stratigraphic unit and it is formed by a basaltic pahoehoe flow field emplaced during the waning phase of volcanic activity of the low-TiO2 lava sequence. Sedimentary interbeds are preserved throughout the whole lava pile and were deposited during quiescence periods of volcanic activity, and represent important stratigraphic markers (e.g. TF-VSF contact). The newly proposed stratigraphy provides promptly recognized stratigraphic units in a regional framework of fundamental importance for future correlations and provide vital information in the understanding of how the Paraná-Etendeka Igneous Province evolved through time.

  6. Records of Triassic volcanism in Pangean Great Lakes, and implications for reconstructing the distal effects of Large Igneous Provinces

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    Whiteside, J. H.; Percival, L.; Kinney, S.; Olsen, P. E.; Mather, T. A.; Philpotts, A.

    2017-12-01

    Documentation of the precise timing of volcanic eruptions in sedimentary records is key for linking volcanic activity to both historical and geological episodes of environmental change. Deposition of tuffs in sediments, and sedimentary enrichment of trace metals linked to igneous processes, are both commonly used for such correlations. In particular, sedimentary mercury (Hg) enrichments have been used as a marker for volcanic activity from Large Igneous Provinces (LIPs) to support their link to episodes of major climate change and mass extinction in the geological record. However, linking such enrichments to a specific eruption or eruption products is often challenging or impossible. In this study, the mercury records from two exactly contemporaneous latest Triassic-earliest Jurassic rift lakes are presented. Both sedimentary records feature igneous units proposed to be related to the later (Early Jurassic) stages of volcanism of the Central Atlantic Magmatic Province (CAMP). These CAMP units include a small tuff unit identified by thin-section petrology and identified at 10 localities over a distance of over 200 km, and a major CAMP basalt flow overlying this tuff (and dated at 200.916±0.064 Ma) which is also known across multiple sedimentary basins in both North America and Morocco and is thought to have been emplaced about 120 kyr after the tuff. A potential stratigraphic correlation between Hg enrichments and the igneous units is considered, and compared to the established records of mercury enrichments from the latest Triassic that are thought to be coeval with the earlier stages of CAMP volcanism. Investigating the Hg records of sedimentary successions containing tuffs and basalt units is an important step for demonstrating whether the mercury emissions from specific individual volcanic eruptions in the deep past can be identified in the geological record, and are thus important tools for interpreting the causes of associated past geological events, such as

  7. Precambrian large igneous provinces: an overview of geochronology, origins and impact on earth evolution

    International Nuclear Information System (INIS)

    Heaman, Larry M.

    2008-01-01

    Precambrian large igneous provinces flourished during the Proterozoic and some, such as the 1.27 Ga Mackenzie event in North America, resemble their Phanerozoic counterparts with good evidence for the production of large volumes of mafic magma in short periods of geologic time (<10 m.y.), a specific focus of this magmatism, and regional uplift prior to the onset of volcanism. In many Precambrian examples, the flood basalts have been largely removed by erosion and only the root zone (e.g. dyke swarm, layered mafic intrusion) of these large igneous provinces is preserved. The short duration of this magmatism and the geometric relationship between linear dyke swarms and basement geology can potentially provide a robust geological pin in continental reconstructions. The extensive 2.37 Ga E-W trending Bangalore dyke swarm in the Dharwar craton, India cross-cuts N-S trending Neoarchean greenstone belts and the 2.51 Ga Closepet granite and is a good example of the potential for providing a cornerstone in Paleoproterozoic continent reconstruction. In contrast, the 1.89 Ga Southern Bastar-Cuddapah large igneous province in southern India is one of several large igneous provinces formed at this time on different continents, including the 1.89-1.88 Ga circum-Superior mafic/ultramafic magmatism in North America and the 1.88-1.87 Ga Waterberg Group sills in South Africa, and is part of a global period of enhanced mantle melting. A challenge for future attempts at Precambrian continent reconstruction is to distinguish between discrete global periods of enhanced mantle melting and a single specific focus large igneous province. (author)

  8. Nonexplosive and explosive magma/wet-sediment interaction during emplacement of Eocene intrusions into Cretaceous to Eocene strata, Trans-Pecos igneous province, West Texas

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    Befus, K.S.; Hanson, R.E.; Miggins, D.P.; Breyer, J.A.; Busbey, A.B.

    2009-01-01

    Eocene intrusion of alkaline basaltic to trachyandesitic magmas into unlithified, Upper Cretaceous (Maastrichtian) to Eocene fluvial strata in part of the Trans-Pecos igneous province in West Texas produced an array of features recording both nonexplosive and explosive magma/wet-sediment interaction. Intrusive complexes with 40Ar/39Ar dates of ~ 47-46??Ma consist of coherent basalt, peperite, and disrupted sediment. Two of the complexes cutting Cretaceous strata contain masses of conglomerate derived from Eocene fluvial deposits that, at the onset of intrusive activity, would have been > 400-500??m above the present level of exposure. These intrusive complexes are inferred to be remnants of diatremes that fed maar volcanoes during an early stage of magmatism in this part of the Trans-Pecos province. Disrupted Cretaceous strata along diatreme margins record collapse of conduit walls during and after subsurface phreatomagmatic explosions. Eocene conglomerate slumped downward from higher levels during vent excavation. Coherent to pillowed basaltic intrusions emplaced at the close of explosive activity formed peperite within the conglomerate, within disrupted Cretaceous strata in the conduit walls, and within inferred remnants of the phreatomagmatic slurry that filled the vents during explosive volcanism. A younger series of intrusions with 40Ar/39Ar dates of ~ 42??Ma underwent nonexplosive interaction with Upper Cretaceous to Paleocene mud and sand. Dikes and sills show fluidal, billowed, quenched margins against the host strata, recording development of surface instabilities between magma and groundwater-rich sediment. Accentuation of billowed margins resulted in propagation of intrusive pillows into the adjacent sediment. More intense disruption and mingling of quenched magma with sediment locally produced fluidal and blocky peperite, but sufficient volumes of pore fluid were not heated rapidly enough to generate phreatomagmatic explosions. This work suggests that

  9. Large igneous provinces (LIPs) and carbonatites

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    Ernst, Richard E.; Bell, Keith

    2010-03-01

    There is increasing evidence that many carbonatites are linked both spatially and temporally with large igneous provinces (LIPs), i.e. high volume, short duration, intraplate-type, magmatic events consisting mainly of flood basalts and their plumbing systems (of dykes, sills and layered intrusions). Examples of LIP-carbonatite associations include: i. the 66 Ma Deccan flood basalt province associated with the Amba Dongar, Sarnu-Dandali (Barmer), and Mundwara carbonatites and associated alkali rocks, ii. the 130 Ma Paraná-Etendeka (e.g. Jacupiranga, Messum); iii. the 250 Ma Siberian LIP that includes a major alkaline province, Maimecha-Kotui with numerous carbonatites, iv. the ca. 370 Ma Kola Alkaline Province coeval with basaltic magmatism widespread in parts of the East European craton, and v. the 615-555 Ma CIMP (Central Iapetus Magmatic Province) of eastern Laurentia and western Baltica. In the Superior craton, Canada, a number of carbonatites are associated with the 1114-1085 Ma Keweenawan LIP and some are coeval with the pan-Superior 1880 Ma mafic-ultramafic magmatism. In addition, the Phalaborwa and Shiel carbonatites are associated with the 2055 Ma Bushveld event of the Kaapvaal craton. The frequency of this LIP-carbonatite association suggests that LIPs and carbonatites might be considered as different evolutionary ‘pathways’ in a single magmatic process/system. The isotopic mantle components FOZO, HIMU, EM1 but not DMM, along with primitive noble gas signatures in some carbonatites, suggest a sub-lithospheric mantle source for carbonatites, consistent with a plume/asthenospheric upwelling origin proposed for many LIPs.

  10. Lateral Variability of Lava flow Morphologies in the Deccan Traps Large Igneous Province (India)

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    Vanderkluysen, L.; Rader, E. L.; Self, S.; Clarke, A. B.; Sheth, H.; Moyer, D. K.

    2016-12-01

    In continental flood basalt provinces (CFBs), lava flow morphologies have traditionally been classified in two distinct groups recognizable in the field, expressing two different modes of lava flow emplacement mechanisms: (a) compound lava flow fields dominated by meter-sized pāhoehoe toes and lobes; and (b) inflated sheet lobes tens to hundreds of meters in width and meters to tens of meters in height. Temporal transitions between these two emplacement styles have been recognized in many mafic large igneous provinces worldwide and seem to be a fundamental feature of CFBs. However, lateral variations in these morphologies remain poorly studied and understood. In the Deccan CFB of India, two principal hypotheses have been proposed to account for possible lateral variations in lava flow facies: that smaller toes and lobes occur in distal regions of flow fields, representing breakouts at the edges of larger inflated lavas; or on the contrary that smaller toes and lobes represent proximal facies. We conducted a field study focusing on two of the Deccan's formations, the Khandala and the Poladpur, located in the middle and upper sections of the province's defined chemostratigraphy. We studied nine sections along a 600 km long E-W transect, with the easternmost sections representing the most distal outcrops, ≥ 500 km away from inferred vents. The Khandala Formation is traditionally described as a sequence of three thick inflated sheet lobes in the well-exposed sections of the western Deccan. However, in the central Deccan, we find the Khandala to be much thicker overall, with half of its thickness dominated by small, meter-sized toes and lobes. Inflated sheet lobes of the Khandala are thinner on average in the central Deccan than further to the east or west. We document this transition as occurring progressively in outcrops only 80 km apart. In the Poladpur, the average thickness of inflated sheet lobes increases in distal outcrops of the eastern Deccan. We interpret

  11. Rock- and Paleomagnetic Properties and Modeling of a Deep Crustal Volcanic System, the Reinfjord Ultramafic Complex, Seiland Igneous Province, Northern Norway

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    ter Maat, G. W.; Pastore, Z.; Michels, A.; Church, N. S.; McEnroe, S. A.; Larsen, R. B.

    2017-12-01

    The Reinfjord Ultramafic Complex is part of the 5000 km2 Seiland Igneous Province (SIP) in Northern Norway. The SIP is argued to be the deep-seated conduit system of a Large Igneous Province and was emplaced at 25-35 km depth in less than 10 Ma (570-560 Ma). The Reinfjord Ultramafic Complex was emplaced during three major successive events at 22-28km depth at pressures of 6-8kb, with associated temperatures 1450-1500°C (Roberts, 2006). The rocks are divided into three formations: the central series (CS) consisting of mainly dunites, upper layered series (ULS) consisting of dunites and wehrlites, a lower layered series (LLS) containing most pyroxene-rich rocks and a marginal zone (MZ) which formed where the ultramafic melts intruded the gabbro-norite and metasedimentary gneisses. Deep exposures such as the Reinfjord Ultramafic Complex are rare, therefore this study gives a unique insight in the rock magnetic properties of a deep ultramafic system. Localised serpentinised zones provide an opportunity to observe the effect of this alteration process on the magnetic properties of deep-seated rocks. Here, we present the results from the rock magnetic properties, a paleomagnetic study and combined potential-fields modeling. The study of the rock magnetic properties provides insight in primary processes associated with the intrusion, and later serpentinization. The paleomagnetic data yields two distinct directions. One direction corresponds to a Laurentia pole at ≈ 532 Ma while the other, though younger, is not yet fully understood. Rock magnetic properties were measured on > 700 specimens and used to constrain the modelling of gravity, high-resolution helicopter, and ground magnetic data. The intrusion is modelled as a cylindrically shaped complex with a dunite core surrounded by wehrlite and gabbro. The ultramafic part of the complex dips to the NE and its maximum vertical extent is modelled to 1400m. Furthermore, modelling allows estimation of relative volumes of

  12. Portrait of a giant deep-seated magmatic conduit system: The Seiland Igneous Province

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    Larsen, Rune B.; Grant, Thomas; Sørensen, Bjørn E.; Tegner, Christian; McEnroe, Suzanne; Pastore, Zeudia; Fichler, Christine; Nikolaisen, Even; Grannes, Kim R.; Church, Nathan; ter Maat, Geertje W.; Michels, Alexander

    2018-01-01

    The Seiland Igneous Province (SIP), Northern Norway, contains > 5000 km2 of mafic and ultramafic intrusions with minor alkaline, carbonatite and felsic rocks that were intruded into the lower continental crust at a depth of 25 to as much as 35 km. The SIP can be geochemically and temporally correlated to numerous dyke swarms throughout Scandinavia at 560-610 Ma, and is linked to magmatic provinces in W-Greenland and NE-America that are collectively known as the Central Iapetus Magmatic Province (CIMP). Revised mapping show that the SIP exposes 85-90% layered tholeiitic- alkaline- and syeno-gabbros, 8-10% peridotitic complexes, 2-5% carbonatite, syenite and diorite that formed within a narrow (mela-gabbro over pyroxenites that grades in to an olivine-clinopyroxenite zone, which is followed by a wehrlite zone and, finally, the centre of the complexes comprises pure dunite. From pyroxenite to dunite, olivine changes from Fo72 to Fo85 and clinopyroxene from Di80 to Di92 i.e. the complexes observe a reverse fractional crystallisation sequence with time. Parental melt compositions modelled from early dykes indicate komatiitic to picritic melts with 16-22 wt% MgO, Cr of 1594 ppm and Ni of 611 ppm, which were emplaced at 1450-1500 °C. Melt compositions calculated from clinopyroxene compositions from Reinfjord are OIB-like with LREE enriched over HREE. The high abundance of carbonatites and lamproites demonstrates the volatile-rich nature of the mantle source region and is further corroborated by the unusually high abundance of magmatic sulphides (0.5-1%) and carbonated and hydrous assemblages (c. 1%) throughout the region. In Reinfjord, they are also closely associated with PGE-Cu-Ni reef deposits. Essentially, the ultramafic complexes in the SIP comprises deep-seated transient magma chambers that facilitated mixing and homogenisation of a rich diversity of fertile asthenospheric melts en route to the upper parts of the continental crust.

  13. Northeast Atlantic Igneous Province volcanic margin development

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    Mjelde, R.; Breivik, A. J.; Faleide, J. I.

    2009-04-01

    Early Eocene continental breakup in the NE Atlantic Volcanic Province (NAIP) was associated with voluminous extrusive and intrusive magmatism, and initial seafloor spreading produced anomalously thick oceanic crust. Recent publications based on crustal-scale wide-angle seismic data show that there is a positive correlation between igneous crustal thickness (H) and average P-wave velocity (Vp) on all investigated margins in the NAIP. Vp can be used as a proxy for crustal composition, which can be related to the mode of mantle melting. A positive H-Vp correlation indicates that excessive mantle melting the first few million years after breakup was driven by an initial increased temperature that cools off as seafloor spreading develops, consistent with a mantle plume model. Variations in mantle composition can explain excess magmatism, but will generate a negative H-Vp correlation. Active mantle convection may increase the flux of mantle rocks through the melting zone above the rate of passive corner flow, which can also produce excessive magmatism. This would produce little H-Vp correlation, and place the curve lower than the passive flow melting curve in the diagram. We have compiled earlier published results with our own analyses of published and unpublished data from different groups to look for systematic variations in the mantle melting mode along the NAIP margins. Earlier studies (Holbrook et al., 2002, White et al, 2008) on the southeast Greenland conjugate system, indicate that the thick igneous crust of the southern NAIP (SE Greenland ? Hatton Bank) was dominated by increased mantle temperature only, while magmatism closer to the southern side of and including the Greenland-Iceland-Færøy Ridge (GIFR) was created by combined temperature increase and active mantle convection. Recent publications (Breivik et al., 2008, White et al, 2008) north of the GIFR for the Norway Basin segment, indicate temperature dominated magmatism between the Jan Mayen Fracture

  14. The Central European, Tarim and Siberian Large Igneous Provinces, Late Palaeozoic orogeny and coeval metallogeny

    NARCIS (Netherlands)

    de Boorder, H.|info:eu-repo/dai/nl/098199056

    2014-01-01

    The formation of the Central European and Tarim Large Igneous Provinces (LIPs) in the Early Permian coincided with the demise of the Variscan and the Southern Tianshan orogens, respectively. The Early Triassic Siberian LIP was formed in the wake of the Western Altaid orogeny in the Late Permian.

  15. The Jiaodong gold district, northeastern China, in the context of the Late Paleozoic and Late Mesozoic large igneous provinces, orogeny and metallogeny in Eurasia

    NARCIS (Netherlands)

    de Boorder, Hugo

    The Permo-Triassic continental large igneous provinces (LIPs) of Eurasia linked in to orogenic systems in decay. Their bulk appearance varies from the massive flood-basalts and (ultra)mafic intrusives to the groups of coeval, widely spread, diverse intrusions and extrusions of the Scattered Igneous

  16. Alkali feldspar syenites with shoshonitic affinities from Chhotaudepur area: Implication for mantle metasomatism in the Deccan large igneous province

    Directory of Open Access Journals (Sweden)

    K.R. Hari

    2014-03-01

    Full Text Available Two petrologically distinct alkali feldspar syenite bodies (AFS-1 and AFS-2 from Chhotaudepur area, Deccan Large Igneous Province are reported in the present work. AFS-1 is characterized by hypidiomorphic texture and consists of feldspar (Or55Ab43 to Or25Ab71, ferro-pargasite/ferro-pargasite hornblende, hastingsite, pyroxene (Wo47, En5, Fs46, magnetite and biotite. AFS-2 exhibits panidiomorphic texture with euhedral pyroxene (Wo47-50, En22-39, Fs12–31 set in a groundmass matrix of alkali feldspar (Or99Ab0.77 to Or1.33Ab98, titanite and magnetite. In comparison to AFS-1, higher elemental concentrations of Ba, Sr and ∑REE are observed in AFS-2. The average peralkaline index of the alkali feldspar syenites is ∼1 indicating their alkaline nature. Variation discrimination diagrams involving major and trace elements and their ratios demonstrate that these alkali feldspar syenites have a shoshonite affinity but emplaced in a within-plate and rifting environment. No evidence of crustal contamination is perceptible in the multi-element primitive mantle normalized diagram as well as in terms of trace elemental ratios. The enrichment of incompatible elements in the alkali feldspar syenites suggests the involvement of mantle metasomatism in their genesis.

  17. The Emeishan large igneous province: A synthesis

    Directory of Open Access Journals (Sweden)

    J. Gregory Shellnutt

    2014-05-01

    Full Text Available The late Permian Emeishan large igneous province (ELIP covers ∼0.3 × 106 km2 of the western margin of the Yangtze Block and Tibetan Plateau with displaced, correlative units in northern Vietnam (Song Da zone. The ELIP is of particular interest because it contains numerous world-class base metal deposits and is contemporaneous with the late Capitanian (∼260 Ma mass extinction. The flood basalts are the signature feature of the ELIP but there are also ultramafic and silicic volcanic rocks and layered mafic-ultramafic and silicic plutonic rocks exposed. The ELIP is divided into three nearly concentric zones (i.e. inner, middle and outer which correspond to progressively thicker crust from the inner to the outer zone. The eruptive age of the ELIP is constrained by geological, paleomagnetic and geochronological evidence to an interval of ≤3 Ma. The presence of picritic rocks and thick piles of flood basalts testifies to high temperature thermal regime however there is uncertainty as to whether these magmas were derived from the subcontinental lithospheric mantle or sub-lithospheric mantle (i.e. asthenosphere or mantle plume sources or both. The range of Sr (ISr ≈ 0.7040–0.7132, Nd (ɛNd(t ≈ −14 to +8, Pb (206Pb/204Pb1 ≈ 17.9–20.6 and Os (γOs ≈ −5 to +11 isotope values of the ultramafic and mafic rocks does not permit a conclusive answer to ultimate source origin of the primitive rocks but it is clear that some rocks were affected by crustal contamination and the presence of near-depleted isotope compositions suggests that there is a sub-lithospheric mantle component in the system. The silicic rocks are derived by basaltic magmas/rocks through fractional crystallization or partial melting, crustal melting or by interactions between mafic and crustal melts. The formation of the Fe-Ti-V oxide-ore deposits is probably due to a combination of fractional crystallization of Ti-rich basalt and fluxing of CO2-rich fluids

  18. 50 Myr of pulsed mafic magmatism in the High Arctic Large Igneous Province

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    Pearson, D. G.; Dockman, D. M.; Heaman, L. M.; Gibson, S. A.; Sarkar, C.

    2017-12-01

    Extensive and voluminous Cretaceous mafic magmatism in the Sverdrup Basin of Arctic Canada forms the circum-Arctic High Arctic Large Igneous Province (HALIP). The small number of published high-precision ages for this LIP indicate its eruption over a considerable timespan raising concerns over whether the HALIP can be strictly defined as a single LIP and questioning the role of a single or multiple plumes in its genesis. Here we present an integrated geochemical and geochronological study to better constrain the timing and cause of mafic magma genesis in the Canadian HALIP. Six new U-Pb and four 40Ar/39Ar ages of mafic lavas and intrusive sheets range from 121 Ma to 78 Ma. The U-Pb ages are the first analyzed from the mafic intrusions of Axel Heiberg and Ellesmere Islands. The new geochronology, combined with other published high-precision ages, reveal a > 50 Myr duration of mafic magmatism in the HALIP defined by three main pulses. Tholeiites dominate the initial 25 Myr of magmatism, transitioning to coeval emplacement of alkali and tholeiitic basalts. Whole-rock Sr-Nd isotope ratios indicate that both magma types are derived from a similar source dominated by convecting mantle. Rare-earth-element inversion models reveal that the alkalic and tholeiitic magmas were generated beneath a bimodal lithospheric `lid' thickness of 65 ± 5 and 45 ± 4 km, respectively. We suggest that the early 128 - 122 Ma tholeiitic event is primarily plume-generated and correlates across the circum-Arctic with the other HALIP tholeiites. Younger HALIP magmatism, with coeval alkalic and tholeiitic magmas erupting over 25 Myr, may be explained by alternating modes of edge-driven mantle convection as the primary control on magma genesis. A distal plume may have intensified magma production by edge-driven convection.

  19. The Teles Pires volcanic province: A paleogeoproterozoic silicic-dominated large igneous province in southwest Amazon craton and tectonic implications

    International Nuclear Information System (INIS)

    Leite, Jayme Alfredo Dexheimer; Saes, Gerson Souza; Macambira, Moacir Jose Buenano

    2001-01-01

    Large Igneous Provinces (LIPs) are important features of the Earth history especially recognized during Paleo to Mezosoic times when they are related to the break up of supercontinents (Coffin and Eldhom, 1994). These provinces occur in several different tectonic settings such as volcanic passive margins, submarine ridges and continental and oceanic plateaux. Mafic-dominanted provinces are the most well known among the LIPs and the best examples are the Karoo, Kerguelem and Ontong-Java. LIPs including an important silicic component have been described in some basaltic provinces of southern Africa (Milner et al. 1992). More recently, silicic-dominated LIPs have been recognized in eastern Australia (Bryan et al., 2000), in southern South America (Pankhurst et al. 1998) and in Antartica Penninsula (Riley and Leat, 1999). The common characteristics of this kind of LIP include: 1) large volume of silicic rocks with dominance of ignimbrites, 2) active over 40 to 50 m.y.; and 3) spatially and temporally associated with plate break up. In this paper we present the main geologic and geochronologic characteristics of the Teles Pires volcanic province from southwest Amazon Craton, which allow its classification as a Paleoprotorozoic silicic-dominated LIP. Geologic implications of this suggestion includes the existence of a large cratonic plate as old as 1.81Ga for the Amazon Craton, therefore the proposed 1.85-1.55 Ga magmatic arc of Rio Negro-Juruena Province should be reviewed (au)

  20. Igneous Intrusion Impacts on Waste Packages and Waste Forms

    International Nuclear Information System (INIS)

    P. Bernot

    2004-01-01

    The purpose of this model report is to assess the potential impacts of igneous intrusion on waste packages and waste forms in the emplacement drifts at the Yucca Mountain Repository. The model is based on conceptual models and includes an assessment of deleterious dynamic, thermal, hydrologic, and chemical impacts. This constitutes the waste package and waste form impacts submodel of the Total System Performance Assessment for the License Application (TSPA-LA) model assessing the impacts of a hypothetical igneous intrusion event on the repository total system performance. This submodel is carried out in accordance with Technical Work Plan for Waste Form Degradation Modeling, Testing, and Analyses in Support of SR and LA (BSC 2003a) and Total System Performance Assessment-License Application Methods and Approaches (BSC 2002a). The technical work plan is governed by the procedures of AP-SIII.10Q, Models. Any deviations from the technical work plan are documented in the TSPA-LA approach to implementing the models for waste package and waste form response during igneous intrusion is based on identification of damage zones. Zone 1 includes all emplacement drifts intruded by the basalt dike, and Zone 2 includes all other emplacement drifts in the repository that are not in Zone 1. This model report will document the following model: (1) Impacts of magma intrusion on the components of engineered barrier system (e.g., drip shields and cladding) of emplacement drifts in Zone 1, and the fate of waste forms. (2) Impacts of conducting magma heat and diffusing magma gases on the drip shields, waste packages, and cladding in the Zone 2 emplacement drifts adjacent to the intruded drifts. (3) Impacts of intrusion on Zone 1 in-drift thermal and geochemical environments, including seepage hydrochemistry. The scope of this model only includes impacts to the components stated above, and does not include impacts to other engineered barrier system (EBS) components such as the invert and

  1. Igneous Intrusion Impacts on Waste Packages and Waste Forms

    Energy Technology Data Exchange (ETDEWEB)

    P. Bernot

    2004-08-16

    The purpose of this model report is to assess the potential impacts of igneous intrusion on waste packages and waste forms in the emplacement drifts at the Yucca Mountain Repository. The model is based on conceptual models and includes an assessment of deleterious dynamic, thermal, hydrologic, and chemical impacts. This constitutes the waste package and waste form impacts submodel of the Total System Performance Assessment for the License Application (TSPA-LA) model assessing the impacts of a hypothetical igneous intrusion event on the repository total system performance. This submodel is carried out in accordance with Technical Work Plan for Waste Form Degradation Modeling, Testing, and Analyses in Support of SR and LA (BSC 2003a) and Total System Performance Assessment-License Application Methods and Approaches (BSC 2002a). The technical work plan is governed by the procedures of AP-SIII.10Q, Models. Any deviations from the technical work plan are documented in the TSPA-LA approach to implementing the models for waste package and waste form response during igneous intrusion is based on identification of damage zones. Zone 1 includes all emplacement drifts intruded by the basalt dike, and Zone 2 includes all other emplacement drifts in the repository that are not in Zone 1. This model report will document the following model: (1) Impacts of magma intrusion on the components of engineered barrier system (e.g., drip shields and cladding) of emplacement drifts in Zone 1, and the fate of waste forms. (2) Impacts of conducting magma heat and diffusing magma gases on the drip shields, waste packages, and cladding in the Zone 2 emplacement drifts adjacent to the intruded drifts. (3) Impacts of intrusion on Zone 1 in-drift thermal and geochemical environments, including seepage hydrochemistry. The scope of this model only includes impacts to the components stated above, and does not include impacts to other engineered barrier system (EBS) components such as the invert and

  2. Deformation mechanisms accommodating the emplacement of an igneous sill-complex in the Irish sector of the Rockall Basin, offshore NW Ireland

    Science.gov (United States)

    Magee, Craig; Jackson, Christopher; Schofield, Nick

    2013-04-01

    Magma intrusion within the subsurface is heavily influenced by the pre-existing architecture of the upper crust and, depending on the emplacement mechanisms, may modify basin structure and fluid flow pathways. Seismic reflection data reveal that intrusive networks predominantly consist of interconnected, saucer-shaped sills that are often associated with dome-shaped 'forced' folds generated by intrusion-induced uplift. Previous studies of intrusion-related forced folds have primarily focused on isolated sills or laccoliths and have shown that the fold amplitude is less than the intrusion thickness, suggesting that additional space-making mechanisms (e.g. grain comminution, fluidization) accompanied emplacement. Furthermore, forced folding is often considered as an instantaneous process over geological time. However, fold growth and the interplay between accompanying ductile and brittle deformation styles remains poorly understood. Here, we use 3D seismic reflection data from the eastern margin of the Irish Rockall Basin, NE Atlantic, to quantitatively study eighty-two igneous intrusions (i.e. saucer-shaped sills and inclined sheets) in order to constrain the emplacement history of a Palaeocene-to-Middle Eocene sill-complex. Emplacement occurred across a Cretaceous clastic-to-marl dominated succession at palaeodepths of limbs. The saucer-shaped sills are characterized by radial magma flow patterns, emanating from the inner sill, distinguished by mapping the long axes of magma lobes and fingers. These magma flow indictors also provide a proxy for intrusion style; i.e. where sills intrude the Lower Cretaceous sandstones, magma propagation was facilitated by brittle fracturing while non-brittle processes (e.g. fluidization) accompanied shallow-level intrusions into the Upper Cretaceous marls. Directly overlying the sill-complex, within the Palaeocene-Mid-Eocene succession, are a series of 22 forced folds that are interpreted to have formed via intrusion-induced uplift

  3. Precise U-Pb Zircon Dating of the Syenite Phase from the Ditrau Alkaline Igneous Complex

    Directory of Open Access Journals (Sweden)

    Pană Dinu

    2000-04-01

    Full Text Available The Ditrău igneous complex represents the largest alkaline intrusion in the Carpathian-Pannonian region consisting of a plethora of rock types formed by complicated magmatic and metasomatic processes. A detailed U-Pb zircon age study is currently underway and the results for the syenite intrusion phase is reported herein. The U-Pb zircon emplacement age of the syenite of 229.6 +1.7/-1.2 Ma documents the quasi-contemporaneous production and emplacement of the gabbro and syenite magmas. We suggest that the syenite and associated granite formed by crustal melting during the emplacement of the mantle derived gabbroic magma around 230 Ma. The thermal contact aureole produced by the Ditrău alkaline igneous complex constrains the main tectonism recorded by surrounding metamorphic lithotectonic assemblages to be pre-Ladinian.

  4. Anisotropy of magnetic susceptibility of silicic rocks from quarries in the vicinity of São Marcos, Rio Grande do Sul, South Brazil: Implications for emplacement mechanisms

    Science.gov (United States)

    Cañón-Tapia, Edgardo; Raposo, M. Irene B.

    2018-04-01

    The Paraná-Etendeka Large Igneous Province includes acid volcanic rocks that can be found throughout its extension. Several aspects concerning those rocks remain controversial, including their mechanism of emplacement and location of their eruptive sources. Opening of several quarries of dimension stone near the city of Sao Marcos, Rio Grande do Sul, Brazil, offers a unique opportunity to study in detail the acid products. Here, we present the results of a study of the anisotropy of magnetic susceptibility (AMS) completed in some rocks that had been interpreted as the roots of volcanic conduits. Our results, and reexamination of the textural features of the rocks, lead to a reinterpretation that suggests that these rocks were emplaced subaerially, and involved assimilation and remelting of clastic components of previous products. Due to the inferred conditions of emplacement, it is unlikely that the eruptive vents are located far from the area of study, therefore ruling out the long-travelled nature of these products.

  5. Features of the distribution of uranium in igneous rocks - uranium deposits associated with igneous rocks

    International Nuclear Information System (INIS)

    Soerensen, H.

    1977-01-01

    The generally accepted main features of the distribution of uranium and thorium in igneous rocks are briefly reviewed. It is pointed out that uranium in most cases examined is strongly partitioned into the melt during consolidation of magmas and that uranium is concentrated in the most volatile-rich parts of magmas. The mode of emplacement and the consolidation of magmas control the retention or the expulsion of the volatile phase from consolidating magmas and also the distribution of uranium between magmas and the volatile phase. After a brief review of the types of uranium deposits associated with igneous rocks it is concluded that it is difficult to establish universally valid exploration criteria to be used in the search of these types of deposit. It is emphasized, however, that detailed petrological and geochemical studies may be useful in outlining exploration targets. (author)

  6. Geological setting, emplacement mechanism and igneous evolution of the Atchiza mafic-ultramafic layered suite in north-west Mozambique

    Science.gov (United States)

    Ibraimo, Daniel Luis; Larsen, Rune B.

    2015-11-01

    The Atchiza mafic and ultramafic-layered suite (hereafter, "Atchiza Suite) crops out in an area 330 km2 west of the Mozambican Tete province. In an early account of the geology of this intrusion, it was considered the continuation of the Great Dyke of Zimbabwe, an idea that was aborted after detailed studies. Nevertheless, the Ni concentrations in the Atchiza outcrop rocks are considerable. Our investigation used field evidence, hand specimens and petrography descriptions, mineral chemistry studies using electron microprobe analysis and tectonic analysis to arrive at a plausible mineralogical composition and understanding of the tectonic setting for the igneous evolution. The mineral composition from the Atchiza Suite indicates that these are cumulates. The magmatic segregation from the petrographic and mineral composition reasoning indicates that dunite-lherzolitic peridotite-olivine gabbro-gabbronorite-gabbro-pegmatitic gabbro is the rock formation sequence. Olivine and chromite were the first phases formed, followed by pyroxene and plagioclase. In addition, it is shown that these minerals are near-liquidus crystallization products of basaltic magma with olivine Fo: 87.06 in dunite, mean values of clinopyroxene are (Wo: 36.4, En: 48.0, Fs: 15.2), orthopyroxene (Wo: 2.95, En: 73.0, Fs: 24.2) and plagioclase An: 71.3, respectively. Opaque minerals comprise Fe-Ti oxides and (Fe, Cr) spinel up to 4.8 vol.%, but chromitite layers are not present. Most of the opaque minerals are interstitial to pyroxene. Sulphides are common in gabbros, with pyrrhotite, pentlandite, chalcopyrite, pyrite and covellite together comprising 0.4-2.0 vol.%. The whole rock Rare Earth Element (REE) concentrations are mainly a result of differentiation, but slight crustal contamination/assimilation contributed to the REE contents. In addition, they also show Eu enrichment, suggesting that plagioclase fractionation was important in the rock. The Atchiza Suite preserves a deep-seated plumbing

  7. Some Environmental Consequences of Large Igneous Provinces

    Science.gov (United States)

    Coffin, M. F.

    2009-12-01

    The formation of large igneous provinces (LIPs)—continental flood basalts, ‘volcanic’ margins, and oceanic plateaus—may impact the atmosphere, oceans, and biosphere by rapidly releasing huge amounts of particulates, magmatic volatiles (CO2, SO2, Cl, F, etc.), and potentially volatiles (CO2, CH4, SO2, etc.) from intruded sediments (e.g., carbonates, organic-rich shales, evaporites). A key factor affecting the magnitude of volatile release is whether eruptions are subaerial or marine; hydrostatic pressure inhibits vesiculation and degassing of relatively soluble volatile components (H2O, S, Cl, F) in deep water submarine eruptions, although low solubility components (CO2, noble gases) are mostly degassed even at abyssal depths. Directly or indirectly, such injections may cause changes in the atmosphere/ocean system that can lead to perturbations of atmosphere/ocean chemistry, circulation, ecology, and biological productivity. These changes can be global in extent, particularly if environmental conditions were at or near a threshold state or tipping point. LIPs may have been responsible for some of the most dramatic and rapid changes in the global environment. For example, between ~145 and ~50 Ma, the global ocean was characterized by chemical and isotopic variations (especially in C and Sr isotope ratios, trace metal concentrations, and biocalcification), relatively high temperatures, high relative sea level, episodic deposition of black shales (oceanic anoxic events), high production of hydrocarbons, mass extinctions of marine organisms, and radiations of marine flora and fauna. Temporal correlations between the intense pulses of igneous activity associated with LIP formation and environmental changes suggest more than pure coincidence. The 1783-84 eruption of Laki on Iceland provides the only historical record of the type of volcanism that constructs transient LIPs. Although Laki produced a basaltic lava flow representing only ~1% of the volume of a typical

  8. Playing jigsaw with Large Igneous Provinces—A plate tectonic reconstruction of Ontong Java Nui, West Pacific

    Science.gov (United States)

    Hochmuth, Katharina; Gohl, Karsten; Uenzelmann-Neben, Gabriele

    2015-11-01

    The three largest Large Igneous Provinces (LIP) of the western Pacific—Ontong Java, Manihiki, and Hikurangi Plateaus—were emplaced during the Cretaceous Normal Superchron and show strong similarities in their geochemistry and petrology. The plate tectonic relationship between those LIPs, herein referred to as Ontong Java Nui, is uncertain, but a joined emplacement was proposed by Taylor (2006). Since this hypothesis is still highly debated and struggles to explain features such as the strong differences in crustal thickness between the different plateaus, we revisited the joined emplacement of Ontong Java Nui in light of new data from the Manihiki Plateau. By evaluating seismic refraction/wide-angle reflection data along with seismic reflection records of the margins of the proposed "Super"-LIP, a detailed scenario for the emplacement and the initial phase of breakup has been developed. The LIP is a result of an interaction of the arriving plume head with the Phoenix-Pacific spreading ridge in the Early Cretaceous. The breakup of the LIP shows a complicated interplay between multiple microplates and tectonic forces such as rifting, shearing, and rotation. Our plate kinematic model of the western Pacific incorporates new evidence from the breakup margins of the LIPs, the tectonic fabric of the seafloor, as well as previously published tectonic concepts such as the rotation of the LIPs. The updated rotation poles of the western Pacific allow a detailed plate tectonic reconstruction of the region during the Cretaceous Normal Superchron and highlight the important role of LIPs in the plate tectonic framework.

  9. Transitions in Lava Emplacement Recorded in the Deccan Traps Sequence (India)

    Science.gov (United States)

    Vanderkluysen, L.; Self, S.; Jay, A. E.; Sheth, H. C.; Clarke, A. B.

    2015-12-01

    Transitions in the style of lava flow emplacement are recognized in the stratigraphic sequence of several mafic large igneous provinces (LIPs), including the Etendeka (Namibia), the Faeroe Islands (North Atlantic LIP), the Ethiopian Traps, and the Deccan Traps (India). These transitions, from units dominated by meter-sized pāhoehoe toes and lobes to those dominated by inflated sheet lobes tens to hundreds of meters in width and meters to tens of meters in height, seems to be a fundamental feature of LIP emplacement. In the Deccan, this volcanological transition is thought to coincide with deeper changes to the volcano-magmatic system expressed, notably, in the trace element and isotopic signature of erupted flows. We investigated this transition in the Deccan Traps by logging eight sequences along the Western Ghats, an escarpment in western India where the Deccan province is thickest and best exposed. The Deccan province, which once covered ~1 million km2 of west-central India, is subdivided in eleven chemo-stratigraphic formations in the type sections of the Western Ghats. Where the lower Deccan formations are exposed, we found that as much as 65% of the exposed thickness (below the Khandala Formation) is made up of sheet lobes, from 40% in the Bhimashankar Formation to 75% in the Thakurvadi Formation. Near the bottom of the sequence, 25% of the Neral Formation is composed of sheet lobes ≥15 m in thickness. On this basis, the traditional view that inflated sheet lobes are an exclusive feature of the upper part of the stratigraphy must be challenged. Several mechanisms have been proposed to explain the development of compound flows and inflated sheet lobes, involving one or more of the following factors: underlying slope, varying effusion rate, and source geometry. Analogue experiments are currently under way to test the relative influence of each of these factors in the development of different lava flow morphologies in LIPs.

  10. IGNEOUS INTRUSION IMPACTS ON WASTE PACKAGES AND WASTE FORMS

    International Nuclear Information System (INIS)

    Bernot, P.

    2004-01-01

    The purpose of this model report is to assess the potential impacts of igneous intrusion on waste packages and waste forms in the emplacement drifts at the Yucca Mountain Repository. The models are based on conceptual models and includes an assessment of deleterious dynamic, thermal, hydrologic, and chemical impacts. The models described in this report constitute the waste package and waste form impacts submodel of the Total System Performance Assessment for the License Application (TSPA-LA) model assessing the impacts of a hypothetical igneous intrusion event on the repository total system performance. This submodel is carried out in accordance with Technical Work Plan for Waste Form Degradation Modeling, Testing, and Analyses in Support of LA (BSC 2004 [DIRS:167796]) and Total System Performance Assessment-License Application Methods and Approaches (BSC 2003 [DIRS: 166296]). The technical work plan was prepared in accordance with AP-2.27Q, Planning for Science Activities. Any deviations from the technical work plan are documented in the following sections as they occur. The TSPA-LA approach to implementing the models for waste package and waste form response during igneous intrusion is based on identification of damage zones. Zone 1 includes all emplacement drifts intruded by the basalt dike, and Zone 2 includes all other emplacement drifts in the repository that are not in Zone 1. This model report will document the following model assessments: (1) Mechanical and thermal impacts of basalt magma intrusion on the invert, waste packages and waste forms of the intersected emplacement drifts of Zone 1. (2) Temperature and pressure trends of basaltic magma intrusion intersecting Zone 1 and their potential effects on waste packages and waste forms in Zone 2 emplacement drifts. (3) Deleterious volatile gases, exsolving from the intruded basalt magma and their potential effects on waste packages of Zone 2 emplacement drifts. (4) Post-intrusive physical

  11. Petrology and U-PB geochronology of the Robertson River Igneous Suite, Blue Ridge province, Virginia - Evidence for multistage magmatism associated witn an early episode of Laurentian rifting

    Science.gov (United States)

    Tollo, R.P.; Aleinikoff, J.N.

    1996-01-01

    The Late Neoproterozoic (735-702 Ma) Robertson River Igneous Suite includes at least eight plutons ranging in composition from syenogranite to alkali feldspar granite to alkali feldspar syenite. These plutons intruded Mesoproterozoic (1.2-1.0 Ga) gneissic basement of the Blue Ridge anticlinorium in northern and central Virginia during an early episode of Laurentian rifting. Robertson River plutons range in composition from metaluminous to peralkaline and, relative to other granite types, exhibit compositional characteristics of A-type granitoids including (1) marked enrichment in Nb, Zr, Y, REE (except Eu), and Ga, (2) high Ga/Al and FeO(total)/MgO, and (3) depletion of Ba and Sr. High Ga/Al ratios are particularly diagnostic of the suite and serve as an effective discriminant between originally metaluminous and peralkaline bulk compositions, providing a useful proxy for widely used indicators based on major elements that are prone to remobilization. U-Pb isotopic analyses of zircons indicate that the suite was emplaced in two pulses, occurring at 735 to 722 and 706 to 702 Ma. Metaluminous magmas were emplaced during both pulses, formed most of the main batholith, and fractionated as independent, time-correlative groups. Peralkaline magmas were emplaced only during the final pulse, formed a volcanic center that erupted unknown quantities of rhyolite, and experienced a style of fractionation similar to the metaluminous types. Differences in Ce/Nb, Y/Nb, and Yb/Ta ratios suggest that the metaluminous and peralkaline magmas were derived from different sources. The Robertson River Igneous Suite is part of a regional group of Late Neoproterozoic (760-700 Ma) plutons including at least 20 other A-type granitoid bodies exposed throughout the Laurentian terrane of Virginia and northwestern North Carolina. Like the Robertson River, most of the other granitoids are metaluminous in composition, typically form multi-intrusive, elongate plutons, and are not geographically

  12. Heat flow study of the Emeishan large igneous province region: Implications for the geodynamics of the Emeishan mantle plume

    Science.gov (United States)

    Jiang, Qiang; Qiu, Nansheng; Zhu, Chuanqing

    2018-01-01

    The Emeishan large igneous province (ELIP) is widely considered to be a consequence of a mantle plume. The supporting evidence includes rapid emplacement, voluminous flood basalt eruptions, and high mantle potential temperature estimates. Several studies have suggested that there was surface uplift prior to the eruption of the Emeishan flood basalts. Additionally, the plume's lateral extent is hard to constrain and has been variously estimated to be 800-1400 km in diameter. In this study, we analyzed present-day heat flow data and reconstructed the Permian paleo-heat flow using vitrinite reflectance and zircon (U-Th)/He thermochronology data in the ELIP region and discussed implications for the geodynamics of the Emeishan mantle plume. The present-day heat flow is higher in the inner and intermediate zones than in the outer zone, with a decrease of average heat flow from 76 mW/m2 to 51 mW/m2. Thermal history modeling results show that an abnormal high paleo-heat flow of 90-110 mW/m2 was caused by the Emeishan mantle plume activity. Based on the present-day heat flow data, we can calculate that there is lithospheric thinning in the central ELIP region, which may be due to the destruction of the lithosphere by mantle plume upwelling and magmatic underplating. The Permian paleo-heat flow anomaly implies that there was a temperature anomaly in the mantle. The ascending high-temperature mantle plume and the thinned lithosphere may have induced the large-scale uplift in the ELIP region. According to the range of the surface heat flow anomaly, it can be estimated that the diameter of the flattened head of the Emeishan mantle plume could have reached 1600-1800 km. Our research provides new insights into the geodynamics of the Emeishan mantle plume through study of heat flow.

  13. Subducted slab-plume interaction traced by magnesium isotopes in the northern margin of the Tarim Large Igneous Province

    Science.gov (United States)

    Cheng, Zhiguo; Zhang, Zhaochong; Xie, Qiuhong; Hou, Tong; Ke, Shan

    2018-05-01

    Incorporation of subducted slabs may account for the geochemical and isotopic variations of large igneous provinces (LIPs). However, the mechanism and process by which subducted slabs are involved into magmas is still highly debated. Here, we report a set of high resolution Mg isotopes for a suite of alkaline and Fe-rich rocks (including basalts, mafic-ultramafic layered intrusions, diabase dykes and mantle xenoliths in the kimberlitic rocks) from Tarim Large Igneous Province (TLIP). We observed that δ26 Mg values of basalts range from -0.29 to - 0.45 ‰, -0.31 to - 0.42 ‰ for mafic-ultramafic layered intrusions, -0.28 to - 0.31 ‰ for diabase dykes and -0.29 to - 0.44 ‰ for pyroxenite xenoliths from the kimberlitic rocks, typically lighter than the normal mantle source (- 0.25 ‰ ± 0.04, 2 SD). After carefully precluding other possibilities, we propose that the light Mg isotopic compositions and high FeO contents should be ascribed to the involvement of recycled sedimentary carbonate rocks and pyroxenite/eclogite. Moreover, from basalts, through layered intrusions to diabase dykes, (87Sr/86Sr)i values and δ18OV-SMOW declined, whereas ε (Nd) t and δ26 Mg values increased with progressive partial melting of mantle, indicating that components of carbonate rock and pyroxenite/eclogite in the mantle sources were waning over time. In combination with the previous reported Mg isotopes for carbonatite, nephelinite and kimberlitic rocks in TLIP, two distinct mantle domains are recognized for this province: 1) a lithospheric mantle source for basalts and mafic-ultramafic layered intrusions which were modified by calcite/dolomite and eclogite-derived high-Si melts, as evidenced by enriched Sr-Nd-O and light Mg isotopic compositions; 2) a plume source for carbonatite, nephelinite and kimberlitic rocks which were related to magnesite or periclase/perovskite involvement as reflected by depleted Sr-Nd-O and extremely light Mg isotopes. Ultimately, our study suggests

  14. High-precision 40Ar/39AR age of the gas emplacement into the Songliao Basin

    NARCIS (Netherlands)

    Qiu, H.N.; Wu, H.Y.; Yun, Y.B.; Feng, Z.H.; Xu, Y.G.; Mei, L.F.; Wijbrans, J.R.

    2011-01-01

    The problem of determining an exact isotopic age of hydrocarbon emplacement is complex because minerals suitable for dating with common isotopic methods are often lacking in the sedimentary domain. However, the igneous quartz from the Cretaceous volcanic rocks that host the gas reservoir in the

  15. Geometry and controls on the development of igneous sill-related forced folds: 2D seismic reflection case study from offshore Southern Australia

    Science.gov (United States)

    Jackson, Christopher; Schofield, Nick; Magee, Craig; Golenkov, Bogdan

    2017-04-01

    Emplacement of magma in the shallow subsurface can result in the development of dome-shaped folds at the Earth's surface. These so-called 'forced folds' have been described in the field and in subsurface datasets, although the exact geometry of the folds and the nature of their relationship to underlying sills remains unclear and, in some cases, controversial. As a result, the utility of these features in tracking the subsurface movement of magma, and predicting the potential size and location of potentially hazardous volcanic eruptions, is uncertain. Here we use high-quality, 2D seismic reflection and borehole data from the Ceduna sub-basin, offshore southern Australia to describe the structure and infer the evolution of igneous sill-related forced folds in the Bight Basin Igneous Complex (BBIC). We mapped 33 igneous sills, which were emplaced 200-1500 m below the palaeo-seabed in an Upper Cretaceous, coal-bearing, predominantly coastal-plain succession. The intrusions, which are expressed as packages of high-amplitude reflections, are 32-250 m thick and 7-19 km in diameter. They are overlain by dome-shaped folds, which are up to 17 km wide and display up to 210 m of relief. The edges of these folds coincide with the margins of the underlying sills and the folds display the greatest relief where the underlying sills are thickest; the folds are therefore interpreted as forced folds that formed in response to emplacement of magma in the shallow subsurface. The folds are onlapped by Lutetian (middle Eocene) strata, indicating they formed and the intrusions were emplaced during the latest Ypresian (c. 48 Ma). We demonstrate that fold amplitude is typically less than sill thickness even for sills with very large diameter-to-depth ratios, suggesting that pure elastic bending (forced folding) of the overburden is not the only process accommodating magma emplacement, and that supra-sill compaction may be important even at relatively shallow depths. Based on the

  16. A tale of two extinctions : converging end-Permian and end-Triassic scenarios

    NARCIS (Netherlands)

    van de Schootbrugge, Bas; Wignall, Paul B.

    The end-Permian (c. 252 Ma) and end-Triassic (c. 201 Ma) mass-extinction events are commonly linked to the emplacement of the large igneous provinces of the Siberia Traps and Central Atlantic Magmatic Province, respectively. Accordingly, scenarios for both extinctions are increasingly convergent and

  17. Environmental implication of subaqueous lava flows from a continental Large Igneous Province: Examples from the Moroccan Central Atlantic Magmatic Province (CAMP)

    Science.gov (United States)

    El Ghilani, S.; Youbi, N.; Madeira, J.; Chellai, E. H.; López-Galindo, A.; Martins, L.; Mata, J.

    2017-03-01

    The Late Triassic-Early Jurassic volcanic sequence of the Central Atlantic Magmatic Province (CAMP) of Morocco is classically subdivided into four stratigraphic units: the Lower, Middle, Upper and Recurrent Formations separated by intercalated sediments deposited during short hiatuses in volcanic activity. Although corresponding to a Large Igneous Province formed in continental environment, it contains subaqueous lava flows, including dominant pillowed flows but also occasional sheet flows. We present a study of the morphology, structure and morphometry of subaqueous lava flows from three sections located at the Marrakech High-Atlas (regions of Aït-Ourir, Jbel Imzar and Oued Lhar-Herissane), as well as an analysis of the sediments, in order to characterize them and to understand their environmental meaning. The analysis of clays by the diffraction method X-ray revealed the presence of illite, mica, phengite, céladonite, talc and small amounts of quartz, hematite, calcite and feldspar, as well as two pairs of interbedded irregular (chlorite Smectite/chlorite-Mica). Fibrous minerals such as sepiolite and palygorskite were not detected. The peperite of Herissane region (Central High Atlas) provided an excellent overview on the factors favoring the magma-sediment interaction. These are the products of a mixture of unconsolidated or poorly consolidated sediments, low permeability with a low viscosity magma. The attempt of dating palynology proved unfortunately without results.

  18. U-Pb zircon geochronology and evolution of some Adirondack meta-igneous rocks

    Science.gov (United States)

    Mclelland, J. M.

    1988-01-01

    An update was presented of the recent U-Pb isotope geochronology and models for evolution of some of the meta-igneous rocks of the Adirondacks, New York. Uranium-lead zircon data from charnockites and mangerites and on baddeleyite from anorthosite suggest that the emplacement of these rocks into a stable crust took place in the range 1160 to 1130 Ma. Granulite facies metamorphism was approximately 1050 Ma as indicated by metamorphic zircon and sphene ages of the anorthosite and by development of magmatitic alaskitic gneiss. The concentric isotherms that are observed in this area are due to later doming. However, an older contact metamorphic aureole associated with anorthosite intrusion is observed where wollastonite develops in metacarbonates. Zenoliths found in the anorthosite indicate a metamorphic event prior to anorthosite emplacement. The most probable mechanism for anorthosite genesis is thought to be ponding of gabbroic magmas at the Moho. The emplacement of the anorogenic anorthosite-mangerite-charnockite suite was apparently bracketed by compressional orogenies.

  19. Sedimentary Mercury Enrichments as a Marker for Submarine Large Igneous Province Volcanism? Evidence From the Mid-Cenomanian Event and Oceanic Anoxic Event 2 (Late Cretaceous)

    Science.gov (United States)

    Scaife, J. D.; Ruhl, M.; Dickson, A. J.; Mather, T. A.; Jenkyns, H. C.; Percival, L. M. E.; Hesselbo, S. P.; Cartwright, J.; Eldrett, J. S.; Bergman, S. C.; Minisini, D.

    2017-12-01

    Oceanic Anoxic Event 2 (OAE 2), during the Cenomanian-Turonian transition (˜94 Ma), was the largest perturbation of the global carbon cycle in the mid-Cretaceous and can be recognized by a positive carbon-isotope excursion in sedimentary strata. Although OAE 2 has been linked to large-scale volcanism, several large igneous provinces (LIPs) were active at this time (e.g., Caribbean, High Arctic, Madagascan, Ontong-Java) and little clear evidence links OAE 2 to a specific LIP. The Mid-Cenomanian Event (MCE, ˜96 Ma), identified by a small, 1‰ positive carbon-isotope excursion, is often referred to as a prelude to OAE 2. However, no underlying cause has yet been demonstrated and its relationship to OAE 2 is poorly constrained. Here we report sedimentary mercury (Hg) concentration data from four sites, three from the southern margin of the Western Interior Seaway and one from Demerara Rise, in the equatorial proto-North Atlantic Ocean. We find that, in both areas, increases in mercury concentrations and Hg/TOC ratios coincide with the MCE and the OAE 2. However, the increases found in these sites are of a lower magnitude than those found in records of many other Mesozoic events, possibly characteristic of a marine rather than atmospheric dispersal of mercury for both events. Combined, the new mercury data presented here are consistent with an initial magmatic pulse at the time of the MCE, with a second, greater pulse at the onset of OAE 2, possibly related to the emplacement of LIPs in the Pacific Ocean and/or the High Arctic.

  20. Magmatic systems of large continental igneous provinces

    Directory of Open Access Journals (Sweden)

    E. Sharkov

    2017-07-01

    Full Text Available Large igneous provinces (LIPs formed by mantle superplume events have irreversibly changed their composition in the geological evolution of the Earth from high-Mg melts (during Archean and early Paleoproterozoic to Phanerozoic-type geochemically enriched Fe-Ti basalts and picrites at 2.3 Ga. We propose that this upheaval could be related to the change in the source and nature of the mantle superplumes of different generations. The first generation plumes were derived from the depleted mantle, whereas the second generation (thermochemical originated from the core-mantle boundary (CMB. This study mainly focuses on the second (Phanerozoic type of LIPs, as exemplified by the mid-Paleoproterozoic Jatulian–Ludicovian LIP in the Fennoscandian Shield, the Permian–Triassic Siberian LIP, and the late Cenozoic flood basalts of Syria. The latter LIP contains mantle xenoliths represented by green and black series. These xenoliths are fragments of cooled upper margins of the mantle plume heads, above zones of adiabatic melting, and provide information about composition of the plume material and processes in the plume head. Based on the previous studies on the composition of the mantle xenoliths in within-plate basalts around the world, it is inferred that the heads of the mantle (thermochemical plumes are made up of moderately depleted spinel peridotites (mainly lherzolites and geochemically-enriched intergranular fluid/melt. Further, it is presumed that the plume heads intrude the mafic lower crust and reach up to the bottom of the upper crust at depths ∼20 km. The generation of two major types of mantle-derived magmas (alkali and tholeiitic basalts was previously attributed to the processes related to different PT-parameters in the adiabatic melting zone whereas this study relates to the fluid regime in the plume heads. It is also suggested that a newly-formed melt can occur on different sides of a critical plane of silica undersaturation and can

  1. Early Cretaceous high-Ti and low-Ti mafic magmatism in Southeastern Tibet: Insights into magmatic evolution of the Comei Large Igneous Province

    Science.gov (United States)

    Wang, Yaying; Zeng, Lingsen; Asimow, Paul D.; Gao, Li-E.; Ma, Chi; Antoshechkina, Paula M.; Guo, Chunli; Hou, Kejun; Tang, Suohan

    2018-01-01

    The Dala diabase intrusion, at the southeastern margin of the Yardoi gneiss dome, is located within the outcrop area of the 132 Ma Comei Large Igneous Province (LIP), the result of initial activity of the Kerguelen plume. We present new zircon U-Pb geochronology results to show that the Dala diabase was emplaced at 132 Ma and geochemical data (whole-rock element and Sr-Nd isotope ratios, zircon Hf isotopes and Fe-Ti oxide mineral chemistry) to confirm that the Dala diabase intrusion is part of the Comei LIP. The Dala diabase can be divided into a high-Mg/low-Ti series and a low-Mg/high-Ti series. The high-Mg/low-Ti series represents more primitive mafic magma compositions that we demonstrate are parental to the low-Mg/high-Ti series. Fractionation of olivine and clinopyroxene, followed by plagioclase within the low-Mg series, lead to systematic changes in concentrations of mantle compatible elements (Cr, Co, Ni, and V), REEs, HFSEs, and major elements such as Ti and P. Some Dala samples from the low-Mg/high-Ti series contain large ilmenite clusters and show extreme enrichment of Ti with elevated Ti/Y ratios, likely due to settling and accumulation of ilmenite during the magma chamber evolution. However, most samples from throughout the Comei LIP follow the Ti-evolution trend of the typical liquid line of descent (LLD) of primary OIB compositions, showing strong evidence of control of Ti contents by differentiation processes. In many other localities, however, primitive magmas are absent and observed Ti contents of evolved magmas cannot be quantitatively related to source processes. Careful examination of the petrogenetic relationship between co-existing low-Ti and high-Ti mafic rocks is essential to using observed rock chemistry to infer source composition, location, and degree of melting.

  2. Genesis of felsic plutonic magmas and their igneous enclaves

    DEFF Research Database (Denmark)

    Clemens, John D.; Maas, Roland; Waight, Tod Earle

    2016-01-01

    -type Pyalong pluton was emplaced, apparently along an east-west-orientated fracture zone. Around 367 Ma, the main I-type Baynton pluton intruded as numerous shallow-dipping sheets. The last plutonic event was the intrusion of the broad, thin, flat-lying, and crosscutting sheet of the I-type Beauvallet pluton...... the relatively high abundance of igneous-textured microgranular enclaves (MEs). The MEs show neither chemical nor isotope mixing trends with each other or with the host magmas. Variations in the Baynton magmas were derived from the heterogeneity of the source terrane, with individual magma batches formed from...

  3. Chemostratigraphy and evolution of the Paraná Igneous Province volcanism in the central portion of the state of Paraná, Southern Brazil

    Science.gov (United States)

    Gomes, Allan Silva; Licht, Otavio Augusto Boni; Vasconcellos, Eleonora Maria Gouvêa; Soares, Jan Savaris

    2018-04-01

    Analysis of borehole samples offers the potential to investigate the chemostratigraphic variations of a large igneous province in subsurface. New geochemical data based on multielement analyses of 829 chip samples that were obtained during the drilling of seven deep boreholes is presented for the central area of the Paraná Igneous Province (PIP). In order to detail the compositional variations found within the two main types from the Central-Northern Subprovince (CNSP), simple statistical treatment was carried out for part this database. Thus, the combination of low (L) and high (H) contents of Th, Nb, La and Yb was used as a means to create 16 geochemical subtypes for the Type 4 (LSi-LZr-HTi-HP) sequence. Likewise, other four elements (Cr, Ni, Cu and Pd) were selected with the same intention for the Type 1 (Central-Northern) (LSi-LZr-LTi-LP) sequence. When subtypes are plotted in the cross section, it is possible to observe that those with similar characteristics tend to be associated in groups (cycles). This analysis showed that the volcanic pile can be divided into at least eleven different cycles and also that they are laterally continuous throughout the section. The compositional changes observed in these volcanic cycles also display correlations with Mg#, Zr, Ti/Y and La/SmN ratios, for example. Therefore, since the reservoir is marked by periods of injection of more differentiated or more mafic magmas, it could be suggested that it was periodically recharged with batches of magma from the parental source.

  4. 118-115 Ma magmatism in the Tethyan Himalaya igneous province: Constraints on Early Cretaceous rifting of the northern margin of Greater India

    Science.gov (United States)

    Chen, Sheng-Sheng; Fan, Wei-Ming; Shi, Ren-Deng; Liu, Xiao-Han; Zhou, Xue-Jun

    2018-06-01

    Understanding the dynamics of Large Igneous Provinces (LIPs) is critical to deciphering processes associated with rupturing continental lithosphere. Microcontinental calving, the rifting of microcontinents from mature continental rifted margins, is particularly poorly understood. Here we present new insights into these processes from geochronological and geochemical analyses of igneous rocks from the Tethyan Himalaya. Early Cretaceous mafic dikes are widely exposed in the eastern and western Tethyan Himalaya, but no such rocks have been reported from the central Tethyan Himalaya. Here we present an analysis of petrological, geochronological, geochemical, and Sr-Nd-Hf-Os isotopic data for bimodal magmatic rocks from the center-east Tethyan Himalaya. Zircon U-Pb dating yields six weighted-mean concordant 206Pb/238U ages of 118 ± 1.2 to 115 ± 1.3 Ma. Mafic rocks display MORB-like compositions with flat to depleted LREE trends, and positive εNd(t) (+2.76 to +5.39) and εHf(t) (+8.0 to +11.9) values. The negative Nb anomalies and relatively high 187Os/188Os ratios (0.15-0.19) of these rocks are related to variable degrees (up to 10%) of crustal contamination. Geochemical characteristics indicate that mafic rocks were generated by variable degrees (2-20%) of partial melting of spinel lherzolites in shallow depleted mantle. Felsic rocks are enriched in Th and LREE, with negative Nb anomalies and decoupling of Nd (εNd(t) = -13.39 to -12.78) and Hf (εHf(t) = -4.8 to -2.0), suggesting that they were derived mainly from garnet-bearing lower continental crust. The geochemical characteristics of the bimodal magmatic associations are comparable to those of associations that form in a continental rift setting. Results indicate that Early Cretaceous magmatism occurred across the whole Tethyan Himalaya, named here as the "Tethyan Himalaya igneous province". Separation of the Tethyan Himalaya from the Indian craton may have occurred during ongoing Early Cretaceous extension

  5. First evidence of lamprophyric magmatism within the Subbetic Zone (Southern Spain)

    NARCIS (Netherlands)

    Puga, E.; Beccaluva, L.; Bianchini, G.; De Federico, A.D.; Puga, M.A.D.; Alvarez-Valero, A.M.; Galindo-Zaldivar, J.; Wijbrans, J.R.

    2010-01-01

    Two drillings carried out at Cerro Prieto (Province of Málaga), together with additional geophysical data, revealed the existence of an igneous body formed of rock-types previously unknown in the Subbetic zone. The recovered rocks, emplaced under hypoabyssal conditions, are predominantly porphyric,

  6. Crystallisation of mela-aillikites of the Narsaq region, Gardar alkaline province, south Greenland and relationships to other aillikitic carbonatitic associations in the province

    Science.gov (United States)

    Upton, B. G. J.; Craven, J. A.; Kirstein, L. A.

    2006-11-01

    Aillikites (carbonated, melilite-free ultramafic lamprophyres grading to carbonatites) are minor components of the Gardar alkaline igneous province. They occur principally as minor intrusions and as clasts in diatremes, but more voluminous aillikitic intrusions crop out near the Ilímaussaq Complex, which they predate by a few million years. These larger intrusions were emplaced at 1160 ± 5 Ma. They are essentially carbonate-free and, consisting almost wholly of ferromagnesian silicate and oxide minerals, are mela-aillikites. Typically the mela-aillikites are fine-grained rocks composed largely of olivine, clinopyroxene, phlogopite and magnetite that crystallised in open systems, permitting loss of volatile-rich residues. The petrography is highly complex, involving at least 28 mineral species. Pyroxenitic veins were emplaced while the host-rocks were still at high temperatures and represent channels through which fluorinated silico-carbonatitic residual melts escaped, with exsolving CO 2 as propellant. Precipitation of Ca-rich minerals including monticellite, perovskite, vesuvianite, wollastonite and cuspidine was a result of dissociation of the calcium carbonate in the residual melts. Late-stage crystallisation was in a highly oxidising environment in which the 'common minerals' attain extreme compositions (almost pure forsterite, ferrian-diopside, highly magnesian ilmenite, Ba-Ti-rich phlogopite and Sr-rich kaersutite). Spatially associated diatremes may be vents through which CO 2-rich gases erupted. The whole-rock compositions are considered to be well removed from those of co-existing melts: compaction and expulsion of highly mobile residual melts is inferred to have left the mela-aillikites as aberrant cumulates. The mela-aillikites are a late-Gardar manifestation of the aillikitic magmatism that occurred intermittently in the province for over 120 Ma. Repetitive formation of metasomite vein systems in the deep lithospheric mantle is postulated. These

  7. The Caribbean-Colombian cretaceous igneous province: The internal anatomy of an oceanic plateau

    Science.gov (United States)

    Kerr, Andrew C.; Tarney, John; Marriner, Giselle F.; Nivia, Alvaro; Saunders, Andrew D.

    The Late Cretaceous Caribbean—Colombian igneous province is one of the world's best-exposed examples of a plume-derived oceanic plateau. The buoyancy of the plateau (resulting from residual heat and thick crust) kept it from being totally subducted as it moved eastward with the Farallon Plate from its site of generation in the eastern Pacific and encountered a destructive plate margin. In effect, the plateau makes up much of the Caribbean Plate; it is well exposed around its margins, but more so in accreted terranes in western Colombia (including the well-known Gorgona komatiites and Bolívar mafic/ultramafic cumulates). Compositionally, the lavas of the plateau form three groups: (a) basalts, picrites, and komatiites with light-rare-earth-element (LREE)-depleted chondrite-normalised patterns; (b) basalts with LREE-enriched patterns; and (c) basalts with essentially flat REE patterns (the most dominant type) similar to many of the basalts from the Ontong Java Plateau. These three types demonstrate the heterogeneous nature of the mantle plume source region. The picrites and the komatiites seem to lie nearer the base of the plateau than the more homogeneous basalts; thus, the more MgO-rich melts may have been erupted before large magma chambers had a chance to develop. A reconstructed crustal cross section through the plateau consists of dunitic and pyroxenitic cumulates near the base which are overlain by layered olivine-rich gabbros and more isotropic gabbros. The lowermost eruptive sequence comprises compositionally heterogeneous picrites/komatiites overlain by more homogeneous pillow basalts. Spectacular hornblende-plagioclase veins cut the Bolívar assemblage and these may represent local partial melts of the plateau's base as it was thrusted onto the continent. Subduction-related batholiths and extrusive rocks found around the margin of the province are of two distinct ages; one suite represents pre-plateau collision-related volcanism whereas the other suite

  8. Dating of authigenic clays related to igneous intrusions in Hunter Valley Coals

    International Nuclear Information System (INIS)

    Zwingmann, H.

    2000-01-01

    The Sydney Basin is composed mainly of Permian and Triassic marine and non-marine clastic sedimentary strata together with economically significant coal deposits and volumetrically minor igneous rocks. Many of these igneous rocks are also economically significant not only for their use in the construction industry but also for their deleterious effects on coal mining, particularly in underground mines utilising longwall extraction systems. Igneous activity in the Sydney Basin ranges from Early Permian to Tertiary in age and although episodic in nature, activity was unlikely to have ceased for periods of more than approximately 10 million years (Carr and Facer 1980; Embleton et al. 1982). Dating of the time of emplacement of igneous rocks using the K-Ar isotopic system is a relatively straightforward procedure if suitable analytical facilities and samples of appropriate, fresh, primary minerals are available. In the case of intrusions in coal seams, however, the occurrence of fresh, primary minerals is very rare due to widespread alteration produced by interaction between the igneous rock and fluids in the coal seam. This interaction produces a variety of secondary minerals with most primary minerals and glass being altered to clays (mainly kaolinite) and carbonates. Consequently, relatively few isotopic dates for intrusions into coal seams have been determined. A detailed study of several hundred samples of igneous rocks from the Sydney Basin found only six samples of intrusions into coal seams that were suitable for conventional K-Ar dating (Carr and Facer 1980). Techniques for K-Ar dating of authigenic illite, developed in response to the need by the petroleum industry to understand the timing of diagenesis in petroleum source-rocks and reservoirs, are now well established (Clauer and Chaudhuri 1995). As part of a larger project on the impact of igneous intrusions on coal mining and the alienation of coal reserves, a preliminary investigation of the timing of

  9. The Park Volcanics Group : field relations of an igneous suite emplaced in the Triassic-Jurassic Murihiku Terrane, South Island, New Zealand

    International Nuclear Information System (INIS)

    Coombs, D.S.; Cook, N.D.J.; Campbell, J.D.

    1992-01-01

    Park Volcanics Group is proposed for igneous rocks, either shallow intrusive or extrusive, emplaced in the Murihiku Terrane during Triassic-Jurassic times. The term replaces Park Intrusives of Mutch, some members of which are shown to be extrusive rather than intrusive. Formation status within the group is given to Gowan Andesite and Pinney Volcanics (new names) in western Southland, Glenham Porphyry in eastern Southland, and Barnicoat Andesite (new) in the Richmond area, Nelson. Gowan Andesite is a porphyritic feldspar two-pyroxene andesite with a glassy or microcrystalline groundmass. A suite of low-grade metavolcanic rocks which forms the main mass of Malakoff Hill and which has formerly been included in the 'Park Intrusives' is here excluded and ascribed to the Takitimu Group; representative chemical data are given. Glenham Porphyry is typically a porphyritic feldspar two-pyroxene andesite texturally similar to the Gowan Andesite but with significant geochemical differences. Two volumetrically minor members are recognised, Habukinini Trachydacite and Kenilworth Rhyolite. In the north of its outcrop area, Glenham Porphyry is emplaced on or into Late Triassic terrestrial beds; in the middle it overlies Kaihikuan (Middle Triassic) and is overlain by Otapirian (latest Triassic) marine beds; and in the southeast it is directly overlain by Ururoan (late Early to early Middle Jurassic) conglomerates and marine sandstones. Pinney Volcanics are restricted to a very few, probably one, massive conglomeratic horizon in the Oretian Stage. The commonest rock type is a two-pyroxene trachydacite, modified by very-low-grade burial metamorphism. Auto-brecciation is characteristic and rock types change over short distances. Hornblende-rich variants occur as well as more felsic varieties including rhyolite ignimbrite. These may have been erupted onto a bouldery floodplain or shallow-marine surface, but alternatively may have been mass-emplaced by debris avalanche resulting from

  10. Physical ages of igneous rocks in the district of Potosi, Bolivia

    International Nuclear Information System (INIS)

    Wolf, M.; Pilot, J.

    1980-01-01

    Age determinations of igneous rocks in the district of Potosi, Bolivia, have been performed using the K-Ar and Rb-Sr methods. The results obtained permit to draw conclusions with regard to the tectono-magmatic evolution of Eastern Cordilleres of Bolivia, and to the prospection and exploration of new deposits in the metallogenetic province

  11. Igneous Rocks

    Science.gov (United States)

    Doe, Bruce R.

    Igneous Rocks was written for undergraduate geology majors who have had a year of college-level chemistry and a course in mineralogy … and for beginning graduate students. Geologists working in industry, government, or academia should find this text useful as a guide to the technical literature up to 1981 and as an overview of topics with which they have not worked but which may have unanticipated pertinence to their own projects.” So starts the preface to this textbook.As one who works part time in research on igneous rocks, especially as they relate to mineral deposits, I have been looking for such a book with this avowed purpose in a field that has a choking richness of evolving terminology and a bewildering volume of interdisciplinary literature. In addition to the standard topics of igneous petrology, the book contains a chapter on the role of igneous activity in the genesis of mineral deposits, its value to geothermal energy, and the potential of igneous rocks as an environment for nuclear waste disposal. These topics are presented rather apologetically in the preface, but the author is to be applauded for including this chapter. The apology shows just how new these interests are to petrology. Recognition is finally coming that, for example, mineral deposits are not “sports of nature,” a view held even by many economic geologists as recently as the early 1960's; instead they are perfectly ordinary geochemical features formed by perfectly ordinary geologic processes. In fact, the mineral deposits and their attendant alteration zones probably have as much to tell us about igneous rocks as the igneous rocks have to tell us about mineral deposits.

  12. Timing and Duration of Volcanism in the North Atlantic Igneous Province: Implications for Geodynamics and Links to the Iceland Hotspot

    DEFF Research Database (Denmark)

    Storey, M.; Duncan, R. A.; Tegner, Christian

    2007-01-01

    estimates of erupted magmas and their cumulates to calculate melt production rates for the early Tertiary flood basalts of East Greenland and the Faeroes Islands. The lavas lie at opposite ends of the Greenland-Iceland-Faeroes Ridge, the postulated Iceland hotspot track, and record volcanic activity leading...... of plate separation. The upper part of this crust comprises seismically imaged, seaward-dipping, subaerially erupted lavas. By  50 Ma, eruption rates had diminished drastically and volcanic activity had narrowed to a much restricted portion of the East Greenland margin, at the western end of the Greenland......We combine new and published 40Ar/39Ar age determinations from incremental heating experiments on whole rocks and mineral separates to assess the timing, duration and distribution of volcanic activity during construction of the North Atlantic Igneous Province. We use these ages together with volume...

  13. Criticality Potential of Waste Packages Containing DOE SNF Affected by Igneous Intrusion

    International Nuclear Information System (INIS)

    D.S. Kimball; C.E. Sanders

    2006-01-01

    The Department of Energy (DOE) is currently preparing an application to submit to the U.S. Nuclear Regulatory Commission for a construction authorization for a monitored geologic repository. The repository will contain spent nuclear fuel (SNF) and defense high-level waste (DHLW) in waste packages placed in underground tunnels, or drifts. The primary objective of this paper is to perform a criticality analysis for waste packages containing DOE SNF affected by a disruptive igneous intrusion event in the emplacement drifts. The waste packages feature one DOE SNF canister placed in the center and surrounded by five High-Level Waste (HLW) glass canisters. The effective neutron multiplication factor (k eff ) is determined for potential configurations of the waste package during and after an intrusive igneous event. Due to the complexity of the potential scenarios following an igneous intrusion, finding conservative and bounding configurations with respect to criticality requires some additional considerations. In particular, the geometry of a slumped and damaged waste package must be examined, drift conditions must be modeled over a range of parameters, and the chemical degradation of DOE SNF and waste package materials must be considered for the expected high temperatures. The secondary intent of this calculation is to present a method for selecting conservative and bounding configurations for a wide range of end conditions

  14. SEM-MLA-based Investigation of the Composition of Mafic Volcaniclastic Deposits from the Paraná Large Igneous Province, Brazil

    Science.gov (United States)

    Höfig, D. F.; Höfig, T. W.; Licht, O. A. B.; Haser, S.; Valore, L.

    2017-12-01

    Mafic volcaniclastic deposits (MVDs) have been widely reported in Large Igneous Provinces around the world, except for the Paraná Province (review by Ross et al., 2005: J Volcanol Geotherm Res, 145, pp. 281-314). Recent geochemical classification for this unit highlights, however, the occurrence of such deposits, connected to basic lava flows, mostly those High Ti - High P ones (Licht.: J Volcanol Geotherm Res, in press). In southern Brazil, MVDs intercalated with lava flows have been reported at 680 sites, showing conspicuous poorly sorted polymictic breccia at the base, grading to tuff breccias and red silicified tuffs at the top. Newly sampled rocks of Paraná mafic volcanoclastic deposits unravel important information about the composition utilizing Scanning Electron Microscopy-based Mineral Liberation Analysis. Overall, they show similar mineralogy presenting obsidian (25-40%), different phases of iron oxide (5-20%), quartz (10-25%), plagioclase (5-25%), celadonite (5-25%), and chlorite (5-10%). The breccias reveal a greater content of celadonite due to the presence of altered hypohyaline and hypocrystalline basaltic shards, whereas the tuffs are more enriched in glass. Different generations of plagioclase are attributed to various basalt shards and clasts as well vitroclasts found in the matrix. It is proposed that the MVDs were generated by explosive events due the interaction between the ascending mafic magma and deep aquifer systems and its siliciclastic matrix represents the country rock, i.e., the underneath Paleozoic sedimentary sequence of Paraná Basin.

  15. PROBABILISTIC ANALYSES OF WASTE PACKAGE QUANTITIES IMPACTED BY POTENTIAL IGNEOUS DISRUPTION AT YUCCA MOUNTAIN

    International Nuclear Information System (INIS)

    M.G. Wallace

    2005-01-01

    A probabilistic analysis was conducted to estimate ranges for the numbers of waste packages that could be damaged in a potential future igneous event through a repository at Yucca Mountain. The analyses include disruption from an intrusive igneous event and from an extrusive volcanic event. This analysis supports the evaluation of the potential consequences of future igneous activity as part of the total system performance assessment for the license application for the Yucca Mountain Project (YMP). The first scenario, igneous intrusion, investigated the case where one or more igneous dikes intersect the repository. A swarm of dikes was characterized by distributions of length, width, azimuth, and number of dikes and the spacings between them. Through the use in part of a latin hypercube simulator and a modified video game engine, mathematical relationships were built between those parameters and the number of waste packages hit. Corresponding cumulative distribution function curves (CDFs) for the number of waste packages hit under several different scenarios were calculated. Variations in dike thickness ranges, as well as in repository magma bulkhead positions were examined through sensitivity studies. It was assumed that all waste packages in an emplacement drift would be impacted if that drift were intersected by a dike. Over 10,000 individual simulations were performed. Based on these calculations, out of a total of over 11,000 planned waste packages distributed over an area of approximately 5.5 km 2 , the median number of waste packages impacted was roughly 1/10 of the total. Individual cases ranged from 0 waste packages to the entire inventory being impacted. The igneous intrusion analysis involved an explicit characterization of dike-drift intersections, built upon various distributions that reflect the uncertainties associated with the inputs. The second igneous scenario, volcanic eruption (eruptive conduits), considered the effects of conduits formed in

  16. The Mozambique Ridge: a document of massive multistage magmatism

    Science.gov (United States)

    Fischer, Maximilian D.; Uenzelmann-Neben, Gabriele; Jacques, Guillaume; Werner, Reinhard

    2017-01-01

    The Mozambique Ridge, a prominent basement high in the southwestern Indian Ocean, consists of four major geomorphological segments associated with numerous phases of volcanic activity in the Lower Cretaceous. The nature and origin of the Mozambique Ridge have been intensely debated with one hypothesis suggesting a Large Igneous Province origin. High-resolution seismic reflection data reveal a large number of extrusion centres with a random distribution throughout the southern Mozambique Ridge and the nearby Transkei Rise. Intrabasement reflections emerge from the extrusion centres and are interpreted to represent massive lava flow sequences. Such lava flow sequences are characteristic of eruptions leading to the formation of continental and oceanic flood basalt provinces, hence supporting a Large Igneous Province origin of the Mozambique Ridge. We observe evidence for widespread post-sedimentary magmatic activity that we correlate with a southward propagation of the East African Rift System. Based on our volumetric analysis of the southern Mozambique Ridge we infer a rapid sequential emplacement between ˜131 and ˜125 Ma, which is similar to the short formation periods of other Large Igneous Provinces like the Agulhas Plateau.

  17. Petrological and geochemical characterization of the plutonic rocks of the Sierra de La Aguada, Province of San Luis, Argentina: Genetic implications with the Famatinian magmatic arc

    Directory of Open Access Journals (Sweden)

    E. Cristofolini

    2017-07-01

    Full Text Available This study presents a synthesis on the geology of the crystalline complex that constitute the Sierra de la Aguada, San Luis province, Argentine, from an approach based on field relations, petrologic and structural features and geochemical characteristic. This mountain range exposes a basement dominated by intermediate to mafic calcalkaline igneous rocks and peraluminous felsic granitoids, both emplaced in low to medium grade metamorphic rocks stabilized under low amphibolite facies. All this lithological terrane has been grouped in the El Carrizal-La Aguada Complex. Field relations, petrographic characterization and geochemical comparison of the plutonic rocks from the study area with those belonging to the Ordovician Famatinian suit exposed in the Sierra Grande de San Luis, suggest a genetic and temporal relation linked to the development of the Famatinian magmatic arc.

  18. A study of radioactive elements of various rocks in Pattani Province with gamma ray spectrometer

    Directory of Open Access Journals (Sweden)

    Kaewtubtim, P.

    2002-01-01

    Full Text Available The radioactivity of the three elements, potassium, uranium and thorium, in rocks of various types in Pattani Province was investigated by using a gamma ray spectrometer. It was found that potassium contents in igneous rocks, sedimentary rocks and metamorphic rocks were 6.29 %, 2.21% and 1.54 % respectively. Uranium equivalent contents in igneous rock, sedimentary rocks and metamorphic rocks were found to be 22.51 ppm, 11.25 ppm and 14.13 ppm, while thorium contents in these rocks were 21.78 ppm, 18.88 ppm and 18.15 ppm respectively. The results obtained were similar to those reported by Pungtip Ranglek (1995 for igneous rock at Liwong Pluton site in Thepha, Na Thawi, Chana and Saba Yoi Districts, Songkhla Province, and were about six times higher than those reported by Kittichai Wattananikorn (1994 for igneous rock in the northern part of Thailand.

  19. Large Igneous Provinces, Their Giant Mafic Dyke Swarms, and Links to Metallogeny

    Science.gov (United States)

    Jowitt, S.; Ernst, R. E.

    2017-12-01

    The relationships between large igneous provinces (LIPs), their giant dyke swarms and differing metallogenic systems can be condensed into five distinct although partially overlapping classifications: (1) LIP magmas that directly generate mineral deposits such as orthomagmatic Ni-Cu-PGE sulfides. Many carbonatites (Nb, Ta REE deposits) and kimberlites (diamonds) are also often LIP related. On the other hand, LIP-related thermal pulses (from a mantle plume) can sometimes destroy diamond potential in the overlying lithosphere. A key locus for Ni-Cu-PGE mineralization is within a few hundred km of the plume center region and plume centers are best located using giant radiating dyke swarms. Dyke subswarms with chalcophile element depletions can also be tracked "upstream" toward the plume center to identify exploration targets. (2) LIP magmas that provide energy, fluids, and/or metals for ore types such as hydrothermal volcanogenic massive sulfide (VMS) and iron oxide-copper-gold (IOCG) deposits. Heat loss from the margins of dykes and sills can also generate local enrichments in key metals (e.g. Co) within the surrounding sedimentary rocks. (3) LIP rocks (particularly sills and dykes) can act barriers to fluid flow and/or as reaction zones that control mineralizing events, act as structural traps within hydrocarbon systems, and form impermeable barriers that control water flow and hence aquifer formation (4) surficial effects, such as the formation of Ni-Co laterites and Al bauxites from tropical weathering of LIP mafic-ultramafic rocks (including volcanics fed by radiating dykes as well as the dykes themselves). This category also includes LIP-related anoxia events that generate hydrocarbon source rocks; and (5) indirect links between LIPs and ore deposits, where continental breakup-related LIP events define a `barcode' record (usually dominated by dyke swarms) that can be used to correlate and reconstruct Precambrian supercontinents. This fifth classification type

  20. Emplacement and Deformation of Mesozoic Gabbros of the High Atlas (Morocco): Paleomagnetism and Magnetic Fabrics

    Science.gov (United States)

    Calvín, P.; Ruiz-Martínez, V. C.; Villalaín, J. J.; Casas-Sainz, A. M.; Moussaid, B.

    2017-12-01

    A paleomagnetic and magnetic fabric study is performed in Upper Jurassic gabbros of the central High Atlas (Morocco). These gabbros were emplaced in the core of preexisting structures developed during the extensional stage and linked to basement faults. These structures were reactivated as anticlines during the Cenozoic compressional inversion. Gabbros from 19 out of the 33 sampled sites show a stable characteristic magnetization, carried by magnetite, which has been interpreted as a primary component. This component shows an important dispersion due to postemplacement tectonic movements. The absence of paleoposition markers in these igneous rocks precludes direct restorations. A novel approach analyzing the orientation of the primary magnetization is used here to restore the magmatic bodies and to understand the deformational history recorded by these rocks. Paleomagnetic vectors are distributed along small circles with horizontal axes, indicating horizontal axis rotations of the gabbro bodies. These rotations are higher when the ratio between shales and gabbros in the core of the anticlines increases. Due to the uncertainties inherent to this work (the igneous bodies recording strong rotations), interpretations must be qualitative. The magnetic fabric is carried by ferromagnetic (s.s.) minerals mimicking the magmatic fabric. Anisotropy of magnetic susceptibility (AMS) axes, using the rotation routine inferred from paleomagnetic results, result in more tightly clustered magnetic lineations, which also become horizontal and are considered in terms of magma flow trend during its emplacement: NW-SE (parallel to the general extensional direction) in the western sector and NE-SW (parallel to the main faults) in the easternmost structures.

  1. The role of igneous sills in shaping the Martian uplands

    Science.gov (United States)

    Wilhelms, D. E.; Baldwin, R. J.

    1989-01-01

    Relations among geologic units and landforms suggest that igneous sills lie beneath much of the intercrater and intracrater terrain of the Martian uplands. The igneous rocks crop out along the upland-lowland front and in crater floors and other depressions that are low enough to intersect the sill's intrusion horizons. It is suggested that heat from the cooling sills melted some of the ice contained in overlying fragmental deposits, creating valley networks by subsurface flow of the meltwater. Terrains with undulatory, smooth surfaces and softened traces of valleys were created by more direct contact with the sills. Widespread subsidence following emplacement of the sills deformed both them and the nonvolcanic deposits that overlie them, accounting for the many structures that continue from ridged plains into the hilly uplands. Crater counts show that the deposit that became valleyed, softened, and ridged probably began to form (and to acquire interstitial ice) during or shortly after the Middle Noachian Epoch, and continued to form as late as the Early Hesperian Epoch. The upper layers of this deposit, many of the visible valleys, and the ridged plains and postulated sills all have similar Early Hesperian ages. Continued formation of valleys is indicated by their incision of fresh-appearing crater ejecta. The dependence of valley formation on internal processes implies that Mars did not necessarily have a dense early atmosphere or warm climate.

  2. Thermally-assisted Magma Emplacement Explains Restless Calderas

    Science.gov (United States)

    Amoruso, A.; Crescentini, L.; D'Antonio, M.; Acocella, V.

    2017-12-01

    Many calderas show repeated unrest over centuries. Though probably induced by magma, this unique behaviour is not understood and its dynamics remains elusive. To better understand these restless calderas, we interpret deformation data and build thermal models of Campi Flegrei, Italy, which is the best-known, yet most dangerous calderas, lying to the west of Naples and restless since the 1950s at least.Our elaboration of the geodetic data indicates that the inflation and deflation of magmatic sources at the same location explain most deformation, at least since the build-up of the last 1538 AD eruption. However, such a repeated magma emplacement requires a persistently hot crust.Our thermal models show that the repeated emplacement was assisted by the thermal anomaly created by magma that was intruded at shallow depth 3 ka before the last eruption and, in turn, contributed to maintain the thermal anomaly itself. This may explain the persistence of the magmatic sources promoting the restless behaviour of the Campi Flegrei caldera; moreover, it explains the crystallization, re-melting and mixing among compositionally distinct magmas recorded in young volcanic rocks.Available information at other calderas highlights similarities to Campi Flegrei, in the pattern and cause of unrest. All monitored restless calderas have either geodetically (Yellowstone, Aira Iwo-Jima, Askja, Fernandina and, partly, Long Valley) or geophysically (Rabaul, Okmok) detected sill-like intrusions inducing repeated unrest. Some calderas (Yellowstone, Long Valley) also show stable deformation pattern, where inflation insists on and mimics the resurgence uplift. The common existence of sill-like sources, also responsible for stable deformation patterns, in restless calderas suggests close similarities to Campi Flegrei. This suggests a wider applicability of our model of thermally-assisted sill emplacement, to be tested by future studies to better understand not only the dynamics of restless

  3. Magmatic evolution and REE mineralization in the early Cambrian Jbel Boho igneous complex in the Bou Azzer inlier (Anti-Atlas/Morocco)

    OpenAIRE

    Benaouda, Rachid

    2015-01-01

    The igneous rocks of Jbel Boho emerged in three phases: an initial phase with alkaline volcanism followed by the intrusion of a syenitic pluton and later the emplacement of a dyke swarm. The Jbel Boho alkaline complex shows some interesting aspects of hydrothermal REE mineralization in the late differentiation stage. REE mineralization is found in a rhyolitic dyke and some late hydrothermal veins. Synchysite-(Ce), which was identified by EPMA analysis, is the main REE mineral.

  4. Correlations between silicic volcanic rocks of the St Mary's Islands (southwestern India) and eastern Madagascar

    DEFF Research Database (Denmark)

    Melluso, Leone; Sheth, Hetu C.; Mahoney, John J.

    2009-01-01

    The St Mary's, Islands (southwestern India) expose silicic volcanic and sub-volcanic rocks (rhyolites and granophyric dacites) emplaced contemporaneously with the Cretaceous igneous province of Madagascar, roughly 88-90 Ma ago. I he St Mary's Islands rocks have phenocrysts of plagioclase...... and isotopic Compositions very close to those of rhyolites exposed between Vatomandry Ilaka and Mananjary in eastern Madagascar, and are distinctly different from rhyolites front other sectors of the Madagascan province. We therefore postulate that the St Mary's and the Vatomandry-Ilaka Mananjary silicic rock...

  5. Emplacement time of Salai Patai carbonatite, Malakand, Pakistan, from fission track dating of zircon and apatite

    International Nuclear Information System (INIS)

    Qureshi, A.A.; Khan, H.A.

    1991-01-01

    Based on fission track dating of zircon and apatite, the emplacement history of Salai Patai carbonatite has been traced. It has been estimated that the carbonatite was emplaced along the thrust plane associated with the Indian-Eurasian plate collision during the Oligocene period followed by some thermal/tectonic episode during Early Miocene. This negates the previous proposal that all carbonatites found in Pakistan are a part of a 200 km long alkaline province associated with the rifting of Peshawar Valley during Late Cretaceous or early tertiary. (author)

  6. High-resolution 40Ar/39Ar chronology of multiple intrusion igneous complexes

    Science.gov (United States)

    Foland, K. A.; Chen, J.-F.; Linder, J. S.; Henderson, C. M. B.; Whillans, I. M.

    1989-06-01

    The Mount Brome complex of the Monteregian province of southern Quebec, Canada, consits of several major intrusions ranging compositionally from gabbro to syenite. The relative ages of these intrusives have been investigated with high-resolution 40Ar/39Ar analyses, including a specially designed irradiation configuration to cancel the effects of fluence gradients. Small yet distinct apparent age differences are observed. While a number of analytical and geological factors could be proposed to explain the small variations, evaluation of these suggests the age differences reflect those in emplacement times. The gabbro and nepheline diorite were emplaced within a short span 123.1 Ma ago. Generally more evolved lithologies (biotite monzodiorite, pulaskite, nordmarkite) appear to have been emplaced within a restricted interval 1.4±0.3 Ma later. Whole-rock Rb-Sr systematics do not give acceptable isochrons because of significant scatter interpreted to reflect initial 87Sr/86Sr heterogeneities resulting from crustal contamination. Considering the variations in initial ratio, the Rb-Sr data are consistent with the 40Ar/39Ar age.

  7. The Central-Western Mediterranean: Anomalous igneous activity in an anomalous collisional tectonic setting

    Science.gov (United States)

    Lustrino, Michele; Duggen, Svend; Rosenberg, Claudio L.

    2011-01-01

    The central-western Mediterranean area is a key region for understanding the complex interaction between igneous activity and tectonics. In this review, the specific geochemical character of several 'subduction-related' Cenozoic igneous provinces are described with a view to identifying the processes responsible for the modifications of their sources. Different petrogenetic models are reviewed in the light of competing geological and geodynamic scenarios proposed in the literature. Plutonic rocks occur almost exclusively in the Eocene-Oligocene Periadriatic Province of the Alps while relatively minor plutonic bodies (mostly Miocene in age) crop out in N Morocco, S Spain and N Algeria. Igneous activity is otherwise confined to lava flows and dykes accompanied by relatively greater volumes of pyroclastic (often ignimbritic) products. Overall, the igneous activity spanned a wide temporal range, from middle Eocene (such as the Periadriatic Province) to the present (as in the Neapolitan of southern Italy). The magmatic products are mostly SiO 2-oversaturated, showing calcalkaline to high-K calcalcaline affinity, except in some areas (as in peninsular Italy) where potassic to ultrapotassic compositions prevail. The ultrapotassic magmas (which include leucitites to leucite-phonolites) are dominantly SiO 2-undersaturated, although rare, SiO 2-saturated (i.e., leucite-free lamproites) appear over much of this region, examples being in the Betics (southeast Spain), the northwest Alps, northeast Corsica (France), Tuscany (northwest Italy), southeast Tyrrhenian Sea (Cornacya Seamount) and possibly in the Tell region (northeast Algeria). Excepted for the Alpine case, subduction-related igneous activity is strictly linked to the formation of the Mediterranean Sea. This Sea, at least in its central and western sectors, is made up of several young (fertile vs. refractory mineralogy), the composition of the subducting plate (i.e., the type and amount of sediment cover and the

  8. On the radiogenic heat production of igneous rocks

    Directory of Open Access Journals (Sweden)

    D. Hasterok

    2017-09-01

    Full Text Available Radiogenic heat production is a physical parameter crucial to properly estimating lithospheric temperatures and properly understanding processes related to the thermal evolution of the Earth. Yet heat production is, in general, poorly constrained by direct observation because the key radiogenic elements exist in trace amounts making them difficulty image geophysically. In this study, we advance our knowledge of heat production throughout the lithosphere by analyzing chemical analyses of 108,103 igneous rocks provided by a number of geochemical databases. We produce global estimates of the average and natural range for igneous rocks using common chemical classification systems. Heat production increases as a function of increasing felsic and alkali content with similar values for analogous plutonic and volcanic rocks. The logarithm of median heat production is negatively correlated (r2 = 0.98 to compositionally-based estimates of seismic velocities between 6.0 and 7.4 km s−1, consistent with the vast majority of igneous rock compositions. Compositional variations for continent-wide models are also well-described by a log-linear correlation between heat production and seismic velocity. However, there are differences between the log-linear models for North America and Australia, that are consistent with interpretations from previous studies that suggest above average heat production across much of Australia. Similar log-linear models also perform well within individual geological provinces with ∼1000 samples. This correlation raises the prospect that this empirical method can be used to estimate average heat production and natural variance both laterally and vertically throughout the lithosphere. This correlative relationship occurs despite a direct causal relationship between these two parameters but probably arises from the process of differentiation through melting and crystallization.

  9. Igneous rocks formed by hypervelocity impact

    Science.gov (United States)

    Osinski, Gordon R.; Grieve, Richard A. F.; Bleacher, Jacob E.; Neish, Catherine D.; Pilles, Eric A.; Tornabene, Livio L.

    2018-03-01

    Igneous rocks are the primary building blocks of planetary crusts. Most igneous rocks originate via decompression melting and/or wet melting of protolith lithologies within planetary interiors and their classification and compositional, petrographic, and textural characteristics, are well-studied. As our exploration of the Solar System continues, so too does the inventory of intrusive and extrusive igneous rocks, settings, and processes. The results of planetary exploration have also clearly demonstrated that impact cratering is a ubiquitous geological process that has affected, and will continue to affect, all planetary objects with a solid surface, whether that be rock or ice. It is now recognized that the production of igneous rocks is a fundamental outcome of hypervelocity impact. The goal of this review is to provide an up-to-date synthesis of our knowledge and understanding of igneous rocks formed by hypervelocity impact. Following a brief overview of the basics of the impact process, we describe how and why melts are generated during impact events and how impact melting differs from endogenic igneous processes. While the process may differ, we show that the products of hypervelocity impact can share close similarities with volcanic and shallow intrusive igneous rocks of endogenic origin. Such impact melt rocks, as they are termed, can display lobate margins and cooling cracks, columnar joints and at the hand specimen and microscopic scale, such rocks can display mineral textures that are typical of volcanic rocks, such as quench crystallites, ophitic, porphyritic, as well as features such as vesicles, flow textures, and so on. Historically, these similarities led to the misidentification of some igneous rocks now known to be impact melt rocks as being of endogenic origin. This raises the question as to how to distinguish between an impact versus an endogenic origin for igneous-like rocks on other planetary bodies where fieldwork and sample analysis may not

  10. Characteristics and Significance of Magma Emplacement Horizons, Black Sturgeon Sill, Nipigon, Ontario

    Science.gov (United States)

    Zieg, M. J.; Hone, S. V.

    2017-12-01

    Spatial scales strongly control the timescales of processes in igneous intrusions, particularly through the thermal evolution of the magma, which in turn governs the evolution of crystallinity, viscosity, and other important physical and chemical properties of the system. In this study, we have collected a highly detailed data set comprising geochemical (bulk rock composition), textural (size and alignment of plagioclase crystals), and mineralogical (modal abundance) profiles through the central portion of the 250 m thick Black Sturgeon diabase sill. In this data, we have identified characteristic signals in texture (soft and somewhat diffuse chills), composition (reversals in differentiation trends), and mineralogy (olivine accumulations), all coinciding and recurring at roughly 10 meter intervals. Based on these signatures, we are able to map out multiple zones representing discrete pulses of magma that were emplaced sequentially as the intrusion was inflated. Simple thermal calculations suggest that each 10 meters of new crystallization would require repose times on the order of 10-100 years. To build up 250 meters of magma at this rate would only require approximately 250-2500 years, significantly less than the thermal lifetime of the entire sill. The soft chills we observe in the Black Sturgeon sill are therefore consistent with a system that remained warm throughout the emplacement process. Successive pulses were injected into partially crystalline mush, rather than pure liquid (which would result in hybridization) or solid (which would produce sharp hard chills). Episodic emplacement is by now widely recognized as a fundamental process in the formation of large felsic magma chambers; our results suggest that this also may be an important consideration in understanding the evolution of smaller mafic intrusions.

  11. An integrative geologic, geochronologic and geochemical study of Gorgona Island, Colombia: Implications for the formation of the Caribbean Large Igneous Province

    Science.gov (United States)

    Serrano, Lina; Ferrari, Luca; Martínez, Margarita López; Petrone, Chiara Maria; Jaramillo, Carlos

    2011-09-01

    The genesis of the Caribbean Large Igneous Province (CLIP) has been associated to the melting of the Galapagos plume head at ~ 90 Ma or to the interaction between the plume and the Caribbean slab window. Gorgona Island, offshore western Colombia, is an accreted fragment of the CLIP and its highly heterogeneous igneous suite, ranging from enriched basalts to depleted komatiites and picrites, was assumed to have formed at ~ 89 Ma from different part of the plume. Here we present new geologic, geochronologic and geochemical data of Gorgona with significant implications for the formation of the CLIP. A new set of 40Ar- 39Ar ages documents a magmatic activity spanning the whole Late Cretaceous (98.7 ± 7.7 to 64.4 ± 5 Ma) followed by a shallower, picritic pyroclastic eruption in the Paleocene. Trace element and isotope geochemistry confirm the existence of an enriched (EDMM: La/Sm N ≥ 1 and ɛNd i of 5.7 to 7.8) and a depleted (DMM: La/Sm N 10%) of a mixed DMM + EDMM (40 to 60%) may reproduce the more depleted rocks with temperatures in the range of ambient mantle in absence of plumes. Our results contradict the notion that the CLIP formed by melting of a plume head at ~ 90 Ma. Multiple magmatic pulses over several tens of Ma in small areas like Gorgona, also recognized in other CLIP areas, suggest a long period of diffuse magmatism without a clear pattern of migration. The age span of this magmatism is broadly concurrent with the Caribbean slab window. During this time span the Farallon oceanic lithosphere (later becoming the Caribbean plate) advanced eastward ~ 1500 km, overriding the astenosphere feeding the proto-Caribbean spreading ridge. This hotter mantle flowed westward into, and mixed with, the opening mantle wedge, promoting increasing melting with time. The fortuitous occurrence of a plume passing through the slab gap area cannot be excluded but not required to produce the observed composition and degree of melting.

  12. Dolerites of Svalbard, north-west Barents Sea Shelf: age, tectonic setting and significance for geotectonic interpretation of the High-Arctic Large Igneous Province

    Directory of Open Access Journals (Sweden)

    Zoltán Pécskay

    2011-08-01

    Full Text Available The dolerites of Svalbard are mineralogically and geochemically homogeneous with geochemical features typical of continental within-plate tholeiites. Their geochemistry is similar to tholeiites belonging to a bimodal suite defined as the High-Arctic Large Igneous Province (HALIP. K–Ar dating of numerous dolerites sampled from many locations across Svalbard define a narrow time span of this magmatism from 125.5±3.6 to 78.3±2.6 Mya. Discrete peaks of intensive activity occurred at 115.3, 100.8, 91.3 and 78.5 Mya corresponding to (1 breakup of the continental crust and formation of an initial rift as a result of mantle plume activity, located in the southern part of the Alpha Ridge; (2 magmatic activity related to spreading along the Alpha Ridge that led to the development of the initial oceanic crust and (3 continuation of spreading along the Alpha Ridge and termination of magmatic activity related to HALIP (last two peaks at 91.3 and 78.5 Mya.

  13. Igneous-related geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R L; Shaw, H R

    1976-01-01

    A preliminary survey of the geothermal resource base associated with igneous-derived thermal anomalies in the upper 10 km of the crust is presented. The approach to numerical estimates of igneous-related heat contents rests on estimates of the probable volumes of high-level magma chambers and determinations of the radiometric ages of the youngest volcanism from those chambers combined with simple thermal calculations based on these values. (MHR)

  14. Geologic history of Siletzia, a large igneous province in the Oregon and Washington Coast Range: correlation to the geomagnetic polarity time scale and implications for a long-lived Yellowstone hotspot

    Science.gov (United States)

    Wells, Ray; Bukry, David; Friedman, Richard; Pyle, Douglas; Duncan, Robert; Haeussler, Peter J.; Wooden, Joe

    2014-01-01

    Siletzia is a basaltic Paleocene and Eocene large igneous province in coastal Oregon, Washington, and southern Vancouver Island that was accreted to North America in the early Eocene. New U-Pb magmatic, detrital zircon, and 40Ar/39Ar ages constrained by detailed field mapping, global nannoplankton zones, and magnetic polarities allow correlation of the volcanics with the 2012 geologic time scale. The data show that Siletzia was rapidly erupted 56–49 Ma, during the Chron 25–22 plate reorganization in the northeast Pacific basin. Accretion was completed between 51 and 49 Ma in Oregon, based on CP11 (CP—Coccolith Paleogene zone) coccoliths in strata overlying onlapping continental sediments. Magmatism continued in the northern Oregon Coast Range until ca. 46 Ma with the emplacement of a regional sill complex during or shortly after accretion. Isotopic signatures similar to early Columbia River basalts, the great crustal thickness of Siletzia in Oregon, rapid eruption, and timing of accretion are consistent with offshore formation as an oceanic plateau. Approximately 8 m.y. after accretion, margin parallel extension of the forearc, emplacement of regional dike swarms, and renewed magmatism of the Tillamook episode peaked at 41.6 Ma (CP zone 14a; Chron 19r). We examine the origin of Siletzia and consider the possible role of a long-lived Yellowstone hotspot using the reconstruction in GPlates, an open source plate model. In most hotspot reference frames, the Yellowstone hotspot (YHS) is on or near an inferred northeast-striking Kula-Farallon and/or Resurrection-Farallon ridge between 60 and 50 Ma. In this configuration, the YHS could have provided a 56–49 Ma source on the Farallon plate for Siletzia, which accreted to North America by 50 Ma. A sister plateau, the Eocene basalt basement of the Yakutat terrane, now in Alaska, formed contemporaneously on the adjacent Kula (or Resurrection) plate and accreted to coastal British Columbia at about the same time

  15. A Low-Li Geochemical Province in the NE Atlantic

    DEFF Research Database (Denmark)

    Bailey, J. C.; Gwozdz, R.

    1978-01-01

    Lithium was analysed in 392 basalts and related igneous rocks from the North Atlantic Tertiary-Recent province using activation analysis and Čerenkov counting. Monotonous Li values of 5.5±2 ppm in NE Atlantic basalts define a low-Li geochemical province which has persisted for 60 million years...... basalt series. No whole-rock coherence is observed between Li and Mg, K, Rb or Ca. Mantle phlogopite is considered to play an insignificant rôle in controlling the Li levels of NE Atlantic basalts....

  16. Emplacement of inflated Pāhoehoe flows in the Naude's Nek Pass, Lesotho remnant, Karoo continental flood basalt province: use of flow-lobe tumuli in understanding flood basalt emplacement

    Science.gov (United States)

    Jay, Anne E.; Marsh, Julian S.; Fluteau, Frédéric; Courtillot, Vincent

    2018-02-01

    Physical volcanological features are presented for a 710-m-thick section, of the Naude's Nek Pass, within the lower part of the Lesotho remnant of the Karoo Large Igneous Province. The section consists of inflated pāhoehoe lava with thin, impersistent sedimentary interbeds towards the base. There are seven discreet packages of compound and hummocky pāhoehoe lobes containing flow-lobe tumuli, making up approximately 50% of the section. Approximately 45% of the sequence consists of 14 sheet lobes, between 10 and 52-m-thick. The majority of the sheet lobes are in two packages indicating prolonged periods of lava supply capable of producing thick sheet lobes. The other sheet lobes are as individual lobes or pairs, within compound flows, suggesting brief increases in lava supply rate. We suggest, contrary to current belief, that there is no evidence that compound flows are proximal to source and sheet lobes (simple flows) are distal to source and we propose that the presence of flow-lobe tumuli in compound flows could be an indicator that a flow is distal to source. We use detailed, previously published, studies of the Thakurvadi Formation (Deccan Traps) as an example. We show that the length of a lobe and therefore the sections that are `medial or distal to source' are specific to each individual lobe and are dependent on the lava supply of each eruptive event, and as such flow lobe tumuli can be used as an indicator of relative distance from source.

  17. Number of Waste Package Hit by Igneous Intrusion

    International Nuclear Information System (INIS)

    M. Wallace

    2004-01-01

    The purpose of this scientific analysis report is to document calculations of the number of waste packages that could be damaged in a potential future igneous event through a repository at Yucca Mountain. The analyses include disruption from an intrusive igneous event and from an extrusive volcanic event. This analysis supports the evaluation of the potential consequences of future igneous activity as part of the total system performance assessment for the license application (TSPA-LA) for the Yucca Mountain Project (YMP). Igneous activity is a disruptive event that is included in the TSPA-LA analyses. Two igneous activity scenarios are considered: (1) The igneous intrusion groundwater release scenario (also called the igneous intrusion scenario) considers the in situ damage to waste packages or failure of waste packages that occurs if they are engulfed or otherwise affected by magma as a result of an igneous intrusion. (2) The volcanic eruption scenario depicts the direct release of radioactive waste due to an intrusion that intersects the repository followed by a volcanic eruption at the surface. An igneous intrusion is defined as the ascent of a basaltic dike or dike system (i.e., a set or swarm of multiple dikes comprising a single intrusive event) to repository level, where it intersects drifts. Magma that does reach the surface from igneous activity is an eruption (or extrusive activity) (Jackson 1997 [DIRS 109119], pp. 224, 333). The objective of this analysis is to develop a probabilistic measure of the number of waste packages that could be affected by each of the two scenarios

  18. Large volume recycling of oceanic lithosphere over short time scales: geochemical constraints from the Caribbean Large Igneous Province

    Science.gov (United States)

    Hauff, F.; Hoernle, K.; Tilton, G.; Graham, D. W.; Kerr, A. C.

    2000-01-01

    Oceanic flood basalts are poorly understood, short-term expressions of highly increased heat flux and mass flow within the convecting mantle. The uniqueness of the Caribbean Large Igneous Province (CLIP, 92-74 Ma) with respect to other Cretaceous oceanic plateaus is its extensive sub-aerial exposures, providing an excellent basis to investigate the temporal and compositional relationships within a starting plume head. We present major element, trace element and initial Sr-Nd-Pb isotope composition of 40 extrusive rocks from the Caribbean Plateau, including onland sections in Costa Rica, Colombia and Curaçao as well as DSDP Sites in the Central Caribbean. Even though the lavas were erupted over an area of ˜3×10 6 km 2, the majority have strikingly uniform incompatible element patterns (La/Yb=0.96±0.16, n=64 out of 79 samples, 2σ) and initial Nd-Pb isotopic compositions (e.g. 143Nd/ 144Nd in=0.51291±3, ɛNdi=7.3±0.6, 206Pb/ 204Pb in=18.86±0.12, n=54 out of 66, 2σ). Lavas with endmember compositions have only been sampled at the DSDP Sites, Gorgona Island (Colombia) and the 65-60 Ma accreted Quepos and Osa igneous complexes (Costa Rica) of the subsequent hotspot track. Despite the relatively uniform composition of most lavas, linear correlations exist between isotope ratios and between isotope and highly incompatible trace element ratios. The Sr-Nd-Pb isotope and trace element signatures of the chemically enriched lavas are compatible with derivation from recycled oceanic crust, while the depleted lavas are derived from a highly residual source. This source could represent either oceanic lithospheric mantle left after ocean crust formation or gabbros with interlayered ultramafic cumulates of the lower oceanic crust. High 3He/ 4He in olivines of enriched picrites at Quepos are ˜12 times higher than the atmospheric ratio suggesting that the enriched component may have once resided in the lower mantle. Evaluation of the Sm-Nd and U-Pb isotope systematics on

  19. Elements of transport and emplacement system

    International Nuclear Information System (INIS)

    1981-02-01

    This report, undertaken to review proposals for transport, handling and emplacement of high-level radioactive wastes in an underground repository, appropriate to the U.K. context, falls under the headings: basic design concepts; waste block size and configuration; self-shielded or partially shielded blocks; concept of emplacement in long boreholes; concept of emplacement in short boreholes; concept of emplacement in tunnels; methods of emplacement; stages of disposal; repository access by adit, incline or shaft; handling techniques within repository; conventional and radiological safety; costs; areas for further research and development. (U.K.)

  20. Formation of a spatter-rich pyroclastic density current deposit in a Neogene sequence of trachytic-mafic igneous rocks at Mason Spur, Erebus volcanic province, Antarctica

    Science.gov (United States)

    Martin, A. P.; Smellie, J. L.; Cooper, A. F.; Townsend, D. B.

    2018-01-01

    Erosion has revealed a remarkable section through the heart of a volcanic island, Mason Spur, in the southwestern Ross Sea, Antarctica, including an unusually well-exposed section of caldera fill. The near-continuous exposure, 10 km laterally and > 1 km vertically, cuts through Cenozoic alkalic volcanic rocks of the Erebus volcanic province (McMurdo Volcanic Group) and permits the study of an ancient volcanic succession that is rarely available due to subsequent burial or erosion. The caldera filling sequence includes an unusual trachytic spatter-rich lapilli tuff (ignimbrite) facies that is particularly striking because of the presence of abundant black fluidal, dense juvenile spatter clasts of trachytic obsidian up to 2 m long supported in a pale cream-coloured pumiceous lapilli tuff matrix. Field mapping indicates that the deposit is an ignimbrite and, together with petrological considerations, it is suggested that mixing of dense spatter and pumiceous lapilli tuff in the investigated deposit occurred during emplacement, not necessarily in the same vent, with the mixed fragmental material emplaced as a pyroclastic density current. Liquid water was not initially present but a steam phase was probably generated during transport and may represent water ingested during passage of the current as it passed over either wet ground, stream, shallow lake or (possibly) snow. Well-exposed caldera interiors are uncommon and that at Mason Spur is helping understand eruption dynamics associated with a complex large island volcano. The results of our study should help to elucidate interpretations of other, less well exposed, pyroclastic density current deposits elsewhere in Antarctica and globally.

  1. The oxidation state of Fe in glasses from the Kerguelen Large Igneous Province: Evidence for the changing oxidation state of the Indian Ocean Basin

    Science.gov (United States)

    Peterson, M. E.; Stolper, E.; Brounce, M. N.; Eiler, J. M.; Wallace, P. J.

    2017-12-01

    Oxygen fugacity (ƒO2) is a thermodynamic property of silicate magmas that can be influenced by volcanic processes such as melting, crystal fractionation, and degassing. Lavas erupted as part of large igneous provinces (LIPs) may reflect the impingement of mantle plumes on the lithosphere, and thus could provide constraints on the ƒO2 of plumes responsible for generation of LIPs. The Kerguelen plateau was emplaced during the break up of Gondwana and the initial opening of the Indian Ocean. Elevated 207Pb/204Pb and 208Pb/204Pb ratios at low 206Pb/204Pb suggests that continental lithosphere from Gondwana is present in the asthenosphere of this region. The Sr-Nd-Pb-He isotopic compositions of the Kerguelen lavas are variable and have been used to infer that the mantle sources of these lavas reflect contributions from the depleted upper mantle, a common plume component, and the EM1 mantle component (perhaps recycled lower continental crust; e.g. Frey et al., 2002). The ƒO2 of the lavas of the Kerguelen LIP may thus reflect mixing of the upper mantle (i.e., near QFM), the plume component, and continental crust. We present new μ-XANES measurements of Fe3+/ΣFe ratios in a suite of 21 submarine glasses from Kerguelen. Over a narrow range in MgO (6.5-7.5 wt%), these glasses have Fe3+/ΣFe ratios of 0.16-0.18, corresponding to an ƒO2 of QFM+0.23 to +0.38 (at 1 atm, 1200°C). The H2O/Ce and Cl/K ratios of these glasses suggest that they did not assimilate significant amounts of altered oceanic crust. Also, S-FeOT variations indicate that the magmas are near sulfide saturation. These lavas were erupted in 1000 m of water, precluding significant loss of S to a vapor phase. At a given MgO content, samples from Kerguelen have similar to higher Fe3+/ΣFe ratios than the average values found in samples from along the Indian mid-ocean ridge, which could indicate a more oxidized mantle source. In addition, increases in Fe3+/ΣFe ratios of the Kerguelen samples, over a narrow

  2. Evolution of the Mazatzal province and the timing of the Mazatzal orogeny: Insights from U-Pb geochronology and geochemistry of igneous and metasedimentary rocks in southern New Mexico

    Science.gov (United States)

    Amato, J.M.; Boullion, A.O.; Serna, A.M.; Sanders, A.E.; Farmer, G.L.; Gehrels, G.E.; Wooden, J.L.

    2008-01-01

    New U-Pb zircon ages, geochemistry, and Nd isotopic data are presented from three localities in the Paleoproterozoic Mazatzal province of southern New Mexico, United States. These data help in understanding the source regions and tectonic setting of magmatism from 1680 to 1620 Ma, the timing of the Mazatzal orogeny, the nature of postorogenic maginatism, Proterozoic plate tectonics, and provide a link between Mazatzal subblocks in Arizona and northern New Mexico. The data indicate a period from 1680 to 1650 Ma in which juvenile felsic granitoids were formed, and a later event between 1646 and 1633 Ma, when these rocks were deformed together with sedimentary rocks. No evidence of pre-1680 Ma rocks or inherited zircons was observed. The igneous rocks have ENd(t) from -1.2 to +4.3 with most between +2 and +4, suggesting a mantle source or derivation from similar-aged crust. Nd isotope and trace element concentrations are consistent with models for typical are magmatism. Detrital zircon ages from metasedimentary rocks indicate that sedimentation occurred until at least 1646 Ma. Both local and Yavapai province sources contributed to the detritus. All of the samples older than ca. 1650 Ma are deformed, whereas undeformed porphyroblasts were found in the contact aureole of a previously dated 1633 Ma gabbro. Regionally, the Mlazatzal orogeny occurred mainly between 1654 and 1643 Ma, during final accretion of a series of island arcs and intervening basins that may have amalgamated offshore. Rhyolite magmatism in the southern Mazatzal province was coeval with gabbro intrusions at 1633 Ma and this bimodal magmatism may have been related to extensional processes following arc accretion. ?? 2007 Geological Society of America.

  3. New zircon data supporting models of short-lived igneous activity at 1.89 Ga in the western Skellefte District, central Fennoscandian Shield

    Directory of Open Access Journals (Sweden)

    P. Skyttä

    2011-10-01

    Full Text Available New U-Th-Pb zircon data (SIMS from three intrusive phases of the Palaeoproterozoic Viterliden intrusion in the western Skellefte District, central Fennoscandian Shield, dates igneous emplacement in a narrow time interval at about 1.89 Ga. A locally occurring quartz-plagioclase porphyritic tonalite, here dated at 1889 ± 3 Ma, is considered the youngest of the intrusive units, based on the new age data and field evidence. This supports an existing interpretation of its fault-controlled emplacement after intrusion of the dominating hornblende-tonalite units, in this study dated at 1892 ± 3 Ma. The Viterliden magmatism was synchronous with the oldest units of the Jörn type early-orogenic intrusions in the eastern part of the district (1.89–1.88 Ga; cf. Gonzàles Roldán, 2010. A U-Pb zircon age for a felsic metavolcanic rock from the hanging-wall to the Kristineberg VMS deposit, immediately south of the Viterliden intrusion, is constrained at 1883 ± 6 Ma in this study. It provides a minimum age for the Kristineberg ore deposit and suggests contemporaneous igneous/volcanic activity throughout the Skellefte District. Furthermore, it supports the view that the Skellefte Group defines a laterally continuous belt throughout this "ore district". Tentative correlation of the 1889 ± 3 Ma quartz-plagioclase porphyritic tonalite with the Kristineberg "mine porphyry" suggests that these units are coeval at about 1.89 Ga. Based on the new age determinations, the Viterliden intrusion may equally well have intruded into or locally acted as a basement for the ore-hosting Skellefte Group volcanic rocks.

  4. River Valley pluton, Ontario - A late-Archean/early-Proterozoic anorthositic intrusion in the Grenville Province

    Science.gov (United States)

    Ashwal, Lewis D.; Wooden, Joseph L.

    1989-01-01

    This paper presents Nd, Sr, and Pb isotopic data indicating a late-Archean/early-Proterozoic age for the River Valley anorthositic pluton of the southwestern Grenville Province of Sudbury, Ontario. Pb-Pb isotopic data on 10 whole-rock samples ranging in composition from anorthosite to gabbro yield an age of 2560 + or - 155 Ma. The River Valley pluton is thus the oldest anorthositic intrusive yet recognized within the Grenville Province. The Sm-Nd isotopic system records an age of 2377 + or - 68 Ma. High Pb-208/Pb-204 of deformed samples relative to igneous-textured rocks implies Th introduction and/or U loss during metamorphism in the River Valley area. Rb-Sr data from igneous-textured and deformed samples and from mineral separates give an age of 2185 + or - 105 Ma, indicating substantial disturbance of the Rb-Sr isotopic system.

  5. Lu-Hf isotope constraints on plume-lithosphere interaction during emplacement of the Bushveld Large Igneous Province at 2.06 Ga: Implications for the structure and evolution of the Kaapvaal Craton's lithospheric mantle

    Science.gov (United States)

    Zirakparvar, N. A.; Mathez, E. A.; Rajesh, H.; Vervoort, J. D.; Choe, S.

    2016-12-01

    The Bushveld Large Igneous Province (B-LIP) comprises a diverse array of >30 magma bodies that intruded the Kaapvaal Craton at 2.06 Ga. In this talk we use zircon and bulk-rock Lu-Hf isotope data to show that the B-LIP formed in response to the arrival of a plume(s) from the deep mantle. New zircon Hf isotope compositions for four B-LIP bodies yield intrusion-specific average ɛHf (2.06 Ga) values that range from -20.7 ± 2.8 to -2.7 ± 2.8, largely consistent with literature zircon data for other B-LIP intrusions. Bulk-rock solution ɛHf (2.06 Ga) values for a variety of B-LIP intrusions range from -2.1 ± 0.2 to -10.6 ± 0.2. Because the most radiogenic Hf isotope compositions across the entire B-LIP are nearly primordial with an ɛHf (2.06 Ga) close to 0, it is likely that the heat source of the B-LIP was a plume(s) from deep mantle. The Hf isotope data further suggests that individual intrusions in the B-LIP can be grouped into four categories based on their ultimate sources: 1) melts generated in subduction and plume modified continental lithospheric mantle; 2) melts generated by melting of a mafic-ultramafic reservoir composed of older ( 2.7 Ga) plume-related material trapped in the Kaapvaal lithosphere; 3) melts generated in the mid- to upper crust; and 4) melts generated from the 2.06 Ga mantle plume itself. The presence of 2.7 Ga mafic-ultramafic material in the Kaapvaal lithosphere may have acted to strengthen the lithosphere so that it was able to resist being dispered by the arrival of the B-LIP plume at 2.06 Ga. Because the B-LIP extends into a 2.7 Ga aged suture zone between the Kaapvaal and Zimbabwe cratons, it is also possible to understand the role of the lithospheric mantle in producing the Lu-Hf signatures observed in the various B-LIP intrusions as a function of two different types of the continental lithosphere: The very old lithosphere comprising the Kaapvaal Craton and the somewhat younger lithosphere comprising the suture zone. A basic

  6. Petrography and Geochemistry (Trace, Ree and Pge of Pedda Cherlo Palle Gabbro-Diorite Pluton, Prakasam Igneous Province, Andhra Pradesh, India

    Directory of Open Access Journals (Sweden)

    Subramanyam K.S.V.

    2015-09-01

    Full Text Available Prakasam Igneous Province (PIP is an important geological domain in the Eastern Dharwar Craton (EDC, found in the junction zone between the EDC and Eastern Ghat Mobile Belt (EGMB. The Pedda Cherlo Palle (PCP gabbros are massive, leucocratic-mesocractic, and show cumulus textures with minerals plagioclase, cpx, and amphiboles. Compositionally, plagioclase is a labradorite-bytownite, cpx is diopside to augite, olivines are hyalosiderites and amphiboles are magnesiohornblendes. PCP gabbros have normal SiO2, high Al2O3, moderate to high TiO2, Na2O and medium Fe2O3, so, classified as subalkaline tholeiitic gabbros. Fractionated rare earth element (REE patterns, high abundance of large ion lithofile elements (LILE and transitional metals coupled with light REE (LREE relative enrichment over heavy REE (HREE and Nb are characteristics of partial melting of depleted mantle and melts that have undergone fractional crystalisation. These partial melts are enriched in LREE and LILE, due to the addition of slab derived sediment and fluids. PCP gabbros contain low abundance (5.1 to 24.6 ng/g of platinum group elements (PGE, and show an increase in the order Ir>Os>Pt>Ru»Pd>Rh. We propose that the subduction related intraoceanic island arc might have accreted to the southeastern margin of India to the east of Cuddapah basin in a collisional regime that took place during Ur to Rodinia amalgamations.

  7. Emplacement engineering

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Ernest E [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

    1970-05-01

    Emplacement Engineering can be defined as that portion of a nuclear explosive project that is concerned with the emplacement of the explosive. This definition would then include virtually everything except the design and fabrication of the explosive and the post-shot-effects program. For future commercial application, the post-shot-effects program will essentially disappear. This emplacement portion of a nuclear explosive project constitutes a large fraction of the total project cost, but it has largely been overshadowed by the explosive and explosive-effects portions. As we move into commercial applications. Emplacement Engineering must receive more attention from both industry and government. To place emplacement costs in their proper relationship with total projects costs, we have performed a study of commercial underground nuclear explosive applications such as gas stimulation. Although there are many intangibles in such a study, we have been able to at least obtain some feel for the relative fractional costs of the non-explosive costs compared with the explosive costs. This study involved estimating the cost elements for applications using a single explosive at 5,000 ft, 10,000 ft, and 15,000 ft. For each depth, the cost estimates were made for a range of emplacement hole and explosive diameters. Results of these estimates for explosive-related costs, hole-related costs, and total costs are shown for the three depths. Note that the explosive package outside diameter is assumed as 2 inches less than the hole (or casing) inside diameter for all cases. For the 5,000-ft application the explosive-related costs dominate, and of particular importance is the indicated diameter for minimum total cost which occurs at approximately a 17.5-in. hole (15.5-in. explosive). The hole-related costs are in 'the same range as the explosive-related costs for the 10,000-ft application. For this case, the minimum total cost occurs at approximately a 14-in. hole (12-in. explosive

  8. Mantle sources and magma evolution of the Rooiberg lavas, Bushveld Large Igneous Province, South Africa

    Science.gov (United States)

    Günther, T.; Haase, K. M.; Klemd, R.; Teschner, C.

    2018-06-01

    We report a new whole-rock dataset of major and trace element abundances and 87Sr/86Sr-143Nd/144Nd isotope ratios for basaltic to rhyolitic lavas from the Rooiberg continental large igneous province (LIP). The formation of the Paleoproterozoic Rooiberg Group is contemporaneous with and spatially related to the layered intrusion of the Bushveld Complex, which stratigraphically separates the volcanic succession. Our new data confirm the presence of low- and high-Ti mafic and intermediate lavas (basaltic—andesitic compositions) with > 4 wt% MgO, as well as evolved rocks (andesitic—rhyolitic compositions), characterized by MgO contents of N, Nb/Y and Ti/Y), indicating a different petrogenesis. MELTS modelling shows that the evolved lavas are formed by fractional crystallization from the mafic low-Ti lavas at low-to-moderate pressures ( 4 kbar). Primitive mantle-normalized trace element patterns of the Rooiberg rocks show an enrichment of large ion lithophile elements (LILE), rare-earth elements (REE) and pronounced negative anomalies of Nb, Ta, P, Ti and a positive Pb anomaly. Unaltered Rooiberg lavas have negative ɛNdi (- 5.2 to - 9.4) and radiogenic ɛSri (6.6 to 105) ratios (at 2061 Ma). These data overlap with isotope and trace element compositions of purported parental melts to the Bushveld Complex, especially for the lower zone. We suggest that the Rooiberg suite originated from a source similar to the composition of the B1-magma suggested as parental to the Bushveld Lower Zone, or that the lavas represent eruptive successions of fractional crystallization products related to the ultramafic cumulates that were forming at depth. The Rooiberg magmas may have formed by 10-20% crustal assimilation by the fractionation of a very primitive mantle-derived melt within the upper crust of the Kaapvaal Craton. Alternatively, the magmas represent mixtures of melts from a primitive, sub-lithospheric mantle plume and an enriched sub-continental lithospheric mantle (SCLM

  9. Neoproterozoic igneous complex emplaced along major tectonic boundary in the Kaoko Belt (NW Namibia): ion probe and LA-ICP-MS dating of magmatic and metamorphic zircons

    Czech Academy of Sciences Publication Activity Database

    Konopásek, J.; Košler, J.; Tajčmanová, L.; Ulrich, Stanislav; Kitt, S. L.

    2008-01-01

    Roč. 165, č. 1 (2008), s. 153-166 ISSN 0016-7649 Institutional research plan: CEZ:AV0Z30120515 Keywords : boundary igneous complex * Kaoko Belt * zircon Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.797, year: 2008

  10. Emplacement of Columbia River flood basalt

    Science.gov (United States)

    Reidel, Stephen P.

    1998-11-01

    Evidence is examined for the emplacement of the Umatilla, Wilbur Creek, and the Asotin Members of Columbia River Basalt Group. These flows erupted in the eastern part of the Columbia Plateau during the waning phases of volcanism. The Umatilla Member consists of two flows in the Lewiston basin area and southwestern Columbia Plateau. These flows mixed to form one flow in the central Columbia Plateau. The composition of the younger flow is preserved in the center and the composition of the older flow is at the top and bottom. There is a complete gradation between the two. Flows of the Wilbur Creek and Asotin Members erupted individually in the eastern Columbia Plateau and also mixed together in the central Columbia Plateau. Comparison of the emplacement patterns to intraflow structures and textures of the flows suggests that very little time elapsed between eruptions. In addition, the amount of crust that formed on the earlier flows prior to mixing also suggests rapid emplacement. Calculations of volumetric flow rates through constrictions in channels suggest emplacement times of weeks to months under fast laminar flow for all three members. A new model for the emplacement of Columbia River Basalt Group flows is proposed that suggests rapid eruption and emplacement for the main part of the flow and slower emplacement along the margins as the of the flow margin expands.

  11. TRANSPORT AND EMPLACEMENT EQUIPMENT DESCRIPTIONS

    International Nuclear Information System (INIS)

    1997-01-01

    The objective and the scope of this document are to list and briefly describe the major mobile equipment necessary for waste package (WP) Transport and Emplacement in the proposed subsurface nuclear waste repository at Yucca Mountain. Primary performance characteristics and some specialized design features of the equipment are explained and summarized in the individual subsections of this document. The Transport and Emplacement equipment described in this document consists of the following: (1) WP Transporter; (2) Reusable Rail Car; (3) Emplacement Gantry; (4) Gantry Carrier; and (5) Transport Locomotive

  12. Crustally derived granites in Dali, SW China: new constraints on silicic magmatism of the Central Emeishan Large Igneous Province

    Science.gov (United States)

    Zhu, Bei; Peate, David W.; Guo, Zhaojie; Liu, Runchao; Du, Wei

    2017-10-01

    We have identified a new crustally derived granite pluton that is related to the Emeishan Large Igneous Province (ELIP). This pluton (the Wase pluton, near Dali) shows two distinct SHRIMP zircon U-Pb age groups ( 768 and 253 Ma). As it has an intrusive relationship with Devonian limestone, the younger age is interpreted as its formation, which is related to the ELIP event, whereas the 768 Ma Neoproterozoic-aged zircons were inherited from Precambrian crustal component of the Yangtze Block, implying the pluton has a crustally derived origin. This is consistent with its peraluminous nature, negative Nb-Ta anomaly, enrichment in light rare earth elements, high 87Sr/86Sr(i) ratio (0.7159-0.7183) and extremely negative ɛ(Nd)(i) values (-12.15 to -13.70), indicative of melts derived from upper crust materials. The Wase pluton-intruded Devonian strata lie stratigraphically below the Shangcang ELIP sequence, which is the thickest volcanic sequence ( 5400 m) in the whole ELIP. The uppermost level of the Shangcang sequence contains laterally restricted rhyolite. Although the rhyolite has the same age as the Wase pluton, its geochemical features demonstrate a different magma origin. The rhyolite displays moderate 87Sr/86Sr(i) (0.7053), slightly negative ɛ(Nd)(i) (-0.18) and depletions in Ba, Cs, Eu and Sr, implying derivation from differentiation of a mantle-derived mafic magma source. The coexistence of crustally and mantle-derived felsic systems, along with the robust development of dike swarms, vent proximal volcanics and thickest flood basalts piles in Dali, shows that the Dali area was probably where the most active Emeishan magmatism had once existed.

  13. A COMPARISON OF MAJOR ELEMENTS BETWEEN MARINE SEDIMENTS AND IGNEOUS ROCKS: AS A BASIC DETERMINATION OF THE SEDIMENT SOURCE AT UJUNG PENYUSUK WATERS, NORTH BANGKA,BANGKA BELITUNG PROVINCE

    Directory of Open Access Journals (Sweden)

    Ediar Usman

    2017-07-01

    Full Text Available Three igneous rock samples from the coast and five sediments from the marine of Ujung Penyusuk Waters have been used for chemistry analysis as the basic determination of sediment source. The result of chemistry analysis shows that the major element with relatively same pattern. In the igneous rock samples, the result of chemistry analysis shows the SiO2 ranges between 72.3 - 76.8%, Al2O3 (9.64 - 11.64%, and Fe2O3 ( 2.08 - 2.18%. In the marine sediment, the content of SiO2 is between 62.2 and 66.5%, Al2O3 (2.93 - 3.63% and Fe2O3 (21.19 - 24.40%. Other elements such as CaO, MgO, K2O, Na2O and TiO2 are relatively similar values in all samples. The difference of element content in marine sediment and coastal igneous rock occurs in Al2O3 and Fe2O3. The Al2O3 is small in marine sediment while the Fe2O3 is higher compared to igneous rocks. Decreasing of the Al2O3 (kaolinite in the marine sediment is caused by the character of the Al2O3 that was derived from quartz rich of igneous rocks forming kaolinite. It was than deposited in the sea floor. Increasing of the Fe2O3 in marine sediment is caused by addition reaction of the Fe from the sea. Generally, the content of the SiO2 (quartz in igneous rock and marine sediment belongs to the same group source that is acid igneous rock. The SiO2 in the sediment belongs to a group of granitoid.

  14. Coronitic metagabbro and eclogite from the Grenville Province of western Quebec: interpretation of U-Pb geochronology and metamorphism

    International Nuclear Information System (INIS)

    Indares, A.; Dunning, G.

    1997-01-01

    We present new U-Pb and metamorphic data on high-pressure coronitic metagabbros from three distinct structural settings in the Parautochthonous belt of the Grenville Province in western Quebec. Intrusive ages are (i) 1217 -10 +15 Ma, for metagabbro close to the Grenville Front, correlative with the Sudbury dykes, defined in Ontario; (ii) 1403 -11 +14 Ma for an eclogitized lens at the base of the highest structural level (SL4), a new age for mafic magmatism in the western Grenville; and (iii) 1218 -34 +53 Ma for metagabbro from SL4, interpreted as correlative with metagabbros from the Algonquin and Shawanaga domains in Ontario. Metamorphism in all cases is Grenvillian, with the best constrained age of 1069 ± 3 Ma for the metagabbro of SL4. Metamorphic grade increases from the Grenville Front to the south. The mafic rocks preserve relict igneous textures overprinted by garnet + clinopyroxene that developed as coronas and (or) pseudomorphs after igneous phases. The highest grade metagabbros contain omphacite and some lack primary plagioclase, therefore being eclogites. However, interpretation of textures and mineral chemistry indicates that they were equilibrated during decompression (at 1350 MPa and 720 o C, sample 51: and at 1200 MPa and 740 o C, sample 29), so maximum depths of burial remain unconstrained. Their evolution is interpreted as follows: (i) high-pressure metamorphism by burial of the Laurentian margin under accreted terranes thrust toward the northwest between 1080 and 1060 Ma; (ii) residence at intermediate crustal levels, for a few tens of millions of years; and (iii) rapid exhumation by renewed thrusting that led to the emplacement of the high-pressure units over the northerly adjacent structural units of the Parautochthonous Belt. (author)

  15. Ground Control for Emplacement Drifts for LA

    International Nuclear Information System (INIS)

    Y. Sun

    2004-01-01

    The purpose of this calculation is to analyze the stability of repository emplacement drifts during the preclosure period, and to provide a final ground support method for emplacement drifts for the License Application (LA). The scope of the work includes determination of input parameter values and loads, selection of appropriate process and methods for the calculation, application of selected methods, such as empirical or analytical, to the calculation, development and execution of numerical models, and evaluation of results. Results from this calculation are limited to use for design of the emplacement drifts and the final ground support system installed in these drifts. The design of non-emplacement openings and their ground support systems is covered in the ''Ground Control for Non-Emplacement Drifts for LA'' (BSC 2004c)

  16. The Late Cretaceous Alkaline Igneous Province in the Iberian Peninsula, and its tectonic significance

    Science.gov (United States)

    Rock, N. M. S.

    1982-04-01

    The Iberian Province consists of the following: the three subvolcanic, syenitic, major intrusive complexes of Monchique, Sines and Sintra in W. and SW Portugal, together with their basanitic/lamprophyric minor intrusive suites; basanitic volcanic complexes around Lisbon; at least some of a widespread suite of basanitic to theralitic minor intrusives in west central Portugal; about 80 small basanitic/lamprophyric to nepheline syenitic intrusions scattered through the Pyrenees, NE Spain, the French Corbières, and off the coast of NW Spain; and the Ormonde Seamount of the Gorringe Bank off the SW coast of Portugal. Most of these occurrences have been dated isotopically or from field evidence as Late Cretaceous. Geological and petrological details of the various occurrences are compiled and reviewed. Primary basanitic magmas were probably parental to the entire Province, and generated syenitic magmas by differentiation processes; oversaturated rocks were produced by alkali loss and perhaps also by crustal involvement. The Iberian Province is related to the opening of the N. Atlantic, specifically that of the Bay of Biscay.

  17. SUBSURFACE EMPLACEMENT TRANSPORTATION SYSTEM

    International Nuclear Information System (INIS)

    Wilson, T.; Novotny, R.

    1999-01-01

    The objective of this analysis is to identify issues and criteria that apply to the design of the Subsurface Emplacement Transportation System (SET). The SET consists of the track used by the waste package handling equipment, the conductors and related equipment used to supply electrical power to that equipment, and the instrumentation and controls used to monitor and operate those track and power supply systems. Major considerations of this analysis include: (1) Operational life of the SET; (2) Geometric constraints on the track layout; (3) Operating loads on the track; (4) Environmentally induced loads on the track; (5) Power supply (electrification) requirements; and (6) Instrumentation and control requirements. This analysis will provide the basis for development of the system description document (SDD) for the SET. This analysis also defines the interfaces that need to be considered in the design of the SET. These interfaces include, but are not limited to, the following: (1) Waste handling building; (2) Monitored Geologic Repository (MGR) surface site layout; (3) Waste Emplacement System (WES); (4) Waste Retrieval System (WRS); (5) Ground Control System (GCS); (6) Ex-Container System (XCS); (7) Subsurface Electrical Distribution System (SED); (8) MGR Operations Monitoring and Control System (OMC); (9) Subsurface Facility System (SFS); (10) Subsurface Fire Protection System (SFR); (11) Performance Confirmation Emplacement Drift Monitoring System (PCM); and (12) Backfill Emplacement System (BES)

  18. Wire-rope emplacement of diagnostics systems

    International Nuclear Information System (INIS)

    Burden, W.L.

    1982-01-01

    The study reported here was initiated to determine if, with the Cable Downhole System (CDS) currently under development, there is an advantage to using continuous wire rope to lower the emplacement package to the bottom of the hole. A baseline design using two wire ropes as well as several alternatives are discussed in this report. It was concluded that the advantages of the wire-rope emplacement system do not justify the cost of converting to such a system, especially for LLNL's maximum emplacement package weights

  19. Mercury anomalies as a proxy for large igneous province volicanism and effects on the carbon cycle in a U-Pb age-constrained section spanning the end-Triassic mass extinction, Levanto, Peru

    Science.gov (United States)

    Yager, J. A.; West, A. J.; Bergquist, B. A.; Thibodeau, A. M.; Corsetti, F. A.; Berelson, W.; Rosas, S.; Bottjer, D. J.

    2017-12-01

    Understanding the causes of the end-Triassic extinction and their potential relationship to Central Atlantic Magmatic Province (CAMP) volcanism necessitates careful correlation of carbon cycle records (largely from marine sections) and volcanism (largely from terrestrial successions) in a robust chronological framework. Here, we report stable carbon isotopes and mercury concentrations and isotopes from the Levanto section in Northern Peru as a putative proxy for CAMP (a large igneous province) in a marine section. Levanto represents deposition well below storm wave base and is lithologically homogenous before, during, and after the end-Triassic extinction interval, making it ideal for detailed chemostratigraphy. Furthermore, abundant intercalated ash beds allow us to correlate mercury concentrations in the marine record directly with CAMP basalt ages, providing a test of the correspondence of mercury anomalies with the eruption of CAMP volcanics. Age dating and C isotope analyses provide an opportunity to explore orbital tuning of the carbon isotope record and ground truth it with existing U-Pb ages from the section, a feature not available in any other marine sections examined to date. The abundance of U-Pb dated ashes in the Levanto section allows us to correlate orbital tuning with other basins, which lack absolute age control, providing a better understanding for the C cycle changes associated with the Triassic-Jurassic boundary.

  20. The Bero Volganic Group: New Lithological, Stratigraphic, and Geochemical Data of this Extension of the Parana-Etendeka Igneous Province into SW Angola with Implications

    Science.gov (United States)

    Marsh, J.; Swart, R.

    2015-12-01

    The Bero Volcanic Group, an extension of the Etendeka-Paraná Igneous Province into SW Angola, forms the eroded basement to the on-shore Namibe Basin, an Early Cretaceous-Cenozoic terrestrial and marine sedimentary sequence. The igneous suite outcrops between latitudes 14.68o and 15.25o S and comprises quartz latite rheoignimbrites/lavas, tholeiitic basaltic lavas, pyroclastic/volcaniclastic deposits, minor aeolian sandstones, and mafic tholeiitic dykes and gabbroic sheets. Quartz latite lithologies dominate. In the Rio Bero area in the S quartz latites are underlain by several thin flows of basalt interbedded with, and underlain by, thin discontinuous lenses of aeolian sandstone. This sequence is consistent with the general stratigraphic sequence in the northern Etendeka of Namibia. To the N basalts and aeolian sandstones are absent and the quartz latites lie directly on Precambrian basement rocks in places. To date, data for a quartz latite correlated with a Chapecó rhyolites of the Paraná are available from only one locality in Angola. This study's wider sampling and major and trace element and radiogenic isotope analysis reveals the following: (1) all mafic rocks are high-Ti, the lavas being equivalent to the Khumiba/Urubici type; (2) mafic dykes cutting the quartz latites having affinities to the Paranapanema-Ribeira mafic lavas; (3) five quartz latite geochemical types are present, three of which are known from Etendeka/Paraná (Sarusas/Guarapuava, Khoraseb/Ourinhos and Ventura) and their stratigraphic relationships in Angola are consistent with those in the Etendeka and Paraná; (4) their Angolan occurrence significantly extends the area covered by, and potential eruptive volumes of, these silicic types; (5) two other quartz latite types are unknown in the Etendeka and Paraná and are probably products of low-volume, local eruptions. The Chinguau type is geochemically similar to the low-Ti quartz lalites of the southern Etendeka but has lower Epsilon Nd

  1. Age constraints on deformation of the eastern Hodgkinson Province, north Queensland: new perspectives on the evolution of the northern Tasman Orogenic Zone

    International Nuclear Information System (INIS)

    Zucchetto, R.G.; Henderson, R.A.; Davis, B.K.; Wysoczanski, R.

    1999-01-01

    Granitic plutons of the Wangetti and Mt Formartine Supersuites intrude the Hodgkinson Formation of the Macalister Range district of the eastern Hodgkinson Province, north Queensland, Australia. Field and microstructural analyses of country-rock fabrics and those of the granites show four deformational events (D 1 -D 4 ) for the district, in common with other sectors of the Hodgkinson Province. Structural relationships show that plutons of the two supersuites were emplaced at different times. The Wangetti Granite lacks fabric development, but the deflection of country-rock cleavage trends around it and the microscale crenulation of S 2 on the rims of D 4 porphyroblasts within its aureole indicate syn-D 4 emplacement, consistent with the Early Permian crystallisation age attributed to this pluton from isotopic evidence. Plutons of the Mt Formartine Supersuite show the effects of multiple (D 2 -D 4 ) deformation. An emplacement age of 357 ± 6 Ma (latest Devonian) was obtained for this granite by SHRIMP U-Pb analyses of zircon. This identifies an early episode of plutonism for the Hodgkinson Province, most granites from which are of Permian age. The new date constrains the age of D 2 for the Macalister Range district and the age of the protolith of the Hodgkinson Formation as pre-Carboniferous. It matches the age previously determined for one of several small, related granitic stocks in the southeastern Camel Creek Subprovince of the Broken River Province. Structural relationships for granites of this age suggest that their emplacement was broadly associated with the first episode of regional-scale orogenesis and the development of penetrative fabrics in the Hodgkinson - Broken River Fold Belt. Copyright (1999) Blackwell Science Pty Ltd

  2. Waste package emplacement borehole option study

    International Nuclear Information System (INIS)

    Streeter, W.S.

    1992-03-01

    This study evaluates the cost and thermal effects of various waste package emplacement configurations that differ in emplacement orientation, number of containers per borehole, and standoff distance at the potential Yucca Mountain nuclear waste repository. In this study, eight additional alternatives to the vertical and horizontal orientation options presented in the Site Characterization Plan Conceptual Design Report are considered. Typical panel layout configurations based on thermal analysis of the waste and cost estimates for design and construction, operations, and closure and decommissioning were made for each emplacement option. For the thermal analysis average waste 10 years out of reactor and the SIM code were used to determine whether the various configurations temperatures would exceed the design criteria for temperature. This study does not make a recommendation for emplacement configuration, but does provide information for comparison of alternatives

  3. Effects of Fault Displacement on Emplacement Drifts

    International Nuclear Information System (INIS)

    Duan, F.

    2000-01-01

    The purpose of this analysis is to evaluate potential effects of fault displacement on emplacement drifts, including drip shields and waste packages emplaced in emplacement drifts. The output from this analysis not only provides data for the evaluation of long-term drift stability but also supports the Engineered Barrier System (EBS) process model report (PMR) and Disruptive Events Report currently under development. The primary scope of this analysis includes (1) examining fault displacement effects in terms of induced stresses and displacements in the rock mass surrounding an emplacement drift and (2 ) predicting fault displacement effects on the drip shield and waste package. The magnitude of the fault displacement analyzed in this analysis bounds the mean fault displacement corresponding to an annual frequency of exceedance of 10 -5 adopted for the preclosure period of the repository and also supports the postclosure performance assessment. This analysis is performed following the development plan prepared for analyzing effects of fault displacement on emplacement drifts (CRWMS M and O 2000). The analysis will begin with the identification and preparation of requirements, criteria, and inputs. A literature survey on accommodating fault displacements encountered in underground structures such as buried oil and gas pipelines will be conducted. For a given fault displacement, the least favorable scenario in term of the spatial relation of a fault to an emplacement drift is chosen, and the analysis is then performed analytically. Based on the analysis results, conclusions are made regarding the effects and consequences of fault displacement on emplacement drifts. Specifically, the analysis will discuss loads which can be induced by fault displacement on emplacement drifts, drip shield and/or waste packages during the time period of postclosure

  4. Igneous Consequence Modeling for the TSPA-SR

    International Nuclear Information System (INIS)

    McCord, John

    2001-01-01

    The purpose of this technical report is to develop credible, defendable, substantiated models for the consequences of igneous activity for the TSPA-SR Model. The effort will build on the TSPA-VA and improve the quality of scenarios and depth of the technical basis underlying disruptive events modeling. Computational models for both volcanic eruptive releases (this is an event that results in ash containing waste being ejected from Yucca Mountain) and igneous intrusion groundwater releases (this is an event that reaches the repository level, impacts the waste packages, and produces releases from waste packages damaged by igneous activity) will be included directly in the TSPA calculations as part of the TSPA-SR Model. This Analysis Model Report (AMR) is limited to development of the conceptual models for these two scenarios. The mathematical implementation of these conceptual models will be done within the TSPA-SR Model. Thus, this AMR will not include any model results or sensitivity analyses. Calculation of any doses resulting from igneous releases will also be done within the TSPA-SR model, as will the probabilistic weighting of these doses. Calculation and analysis of the TSPA-SR Model results for igneous disruption are, therefore, outside the scope of this activity. The reason for not running the mathematical models as part of this AMR is that the models are integrated within the TSPA-SR model and, thus, any model simulations and the corresponding results are out of the scope of this AMR. The scope of this work as defined in the development plan (CRWMS M and O 2000j) involves using data that has been extracted from existing sources to design and support the TSPA-SR models for the transport of radionuclides following igneous disruption of the repository. The development plan states ''applications of the code in this analysis will be limited to testing of the code and sensitivity analyses during analysis design.'' In contrast to the development plan, the ASHPLUME

  5. Igneous-sedimentary petroleum systems; Sistemas petroliferos igneo-sedimentares

    Energy Technology Data Exchange (ETDEWEB)

    Eiras, Jaime Fernandes [Para Univ., Belem, PA (Brazil)]. E-mail: eiras@ufpa.br; Wanderley Filho, Joaquim Ribeiro [PETROBRAS S.A., Manaus, AM (Brazil). Unidade de Negocios-BSOL]. E-mail: jwand@petrobras.com.br

    2003-07-01

    Igneous-sedimentary petroleum systems are mixed systems in which one or more essential elements or processes are related to magmatic events. Many examples worldwide are presented to show the importance of igneous rocks in the exploratory activities, as well as in the petroleum occurrence. Volcanic ash layers are of great importance in stratigraphic correlation and elucidation of structures, particularly when they occur in thick nonfossiliferous strata. They are also good indicators of turbidite deposition where turbidity currents are related to earthquakes generated by magmatic events. Unconventional reservoirs can be created by volcanic eruptions or intrusions, crystallization, reworking, and fracturing. Unaltered igneous rocks can seal vertically and laterally conventional reservoirs due to its excellent cap capacity. Abnormal thermal effect of igneous rocks can compensate the lack of overburden in shallow basins. Structural or combined traps can be formed due to intrusions, such as folded, faulted, and unconformity traps. Porosity can be either primary or secondary, or both. Primary porosity mainly consists of cavities produced by gas volatilization during eruption and cooling. Secondary porosity refers to those pores that result from hydrothermal alteration, recrystallization, and dissolution by groundwater, and tectonic stress. It includes intercrystalline pores formed by crystallization of various secondary minerals, dissolution pores, and tectonic fractures. New technologies of petroleum development and production are encouraging to search for oil and gas within igneous rocks, and new discoveries are expected. (author)

  6. Deep Borehole Emplacement Mode Hazard Analysis Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Sevougian, S. David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-08-07

    This letter report outlines a methodology and provides resource information for the Deep Borehole Emplacement Mode Hazard Analysis (DBEMHA). The main purpose is identify the accident hazards and accident event sequences associated with the two emplacement mode options (wireline or drillstring), to outline a methodology for computing accident probabilities and frequencies, and to point to available databases on the nature and frequency of accidents typically associated with standard borehole drilling and nuclear handling operations. Risk mitigation and prevention measures, which have been incorporated into the two emplacement designs (see Cochran and Hardin 2015), are also discussed. A key intent of this report is to provide background information to brief subject matter experts involved in the Emplacement Mode Design Study. [Note: Revision 0 of this report is concentrated more on the wireline emplacement mode. It is expected that Revision 1 will contain further development of the preliminary fault and event trees for the drill string emplacement mode.

  7. Ground Control for Non-Emplacement Drifts for LA

    International Nuclear Information System (INIS)

    Tang, D.

    2004-01-01

    The purpose of this calculation is to analyze the stability of repository non-emplacement drifts during the preclosure period, and to provide a final ground support method for non-emplacement drifts for the License Application (LA). This calculation will provide input for the development of LA documents. The scope of this calculation is limited to the non-emplacement drifts including access mains, ramps, exhaust mains, turnouts, intersections between access mains and turnouts, and intersections between exhaust mains and emplacement drifts, portals, TBM launch chambers, observation drift and test alcove in the performance confirmation (PC) facilities, etc. The calculation is limited to the non-emplacement drifts subjected to a combined loading of in-situ stress, seismic stress, and/or thermal stress. Other effects such as hydrological and chemical effects are not considered in this analysis

  8. Construction, emplacement, and retrievability (preclosure)

    International Nuclear Information System (INIS)

    McClain, W.

    1985-01-01

    Each of the three preclosure subgroups of the Construction, Emplacement, and Retrievability Working Group adopted a six-step approach to identify and assess current needs in geotechnical modeling and characterization. This approach may be summarized as follows: identify phenomena related to emplacement of high-level nuclear wastes, identify types of models which are required to calculate the phenomena, establish the input data needs for the models, assess the current availability of the models, assess the current status of documentation, verification, and validation of the models, and determine the adequacy of instrumentation and measurement techniques to (a) validate the models, where necessary, and (b) obtain input data for design. Systematic application of these six steps leads to the establishment of the research requirements for geotechnical modeling and characterization. A summary of modeling techniques which apply to the three subsequent sections on construction, emplacement, and retrievability is presented. Research needs, which apply to all preclosure activities, are summarized

  9. Ground Control for Emplacement Drifts for SR

    International Nuclear Information System (INIS)

    Y. Sun

    2000-01-01

    This analysis demonstrates that a satisfactory ground control system can be designed for the Yucca Mountain site, and provides the technical basis for the design of ground support systems to be used in repository emplacement and non-emplacement drifts. The repository ground support design was based on analytical methods using acquired computer codes, and focused on the final support systems. A literature review of case histories, including the lessons learned from the design and construction of the ESF, the studies on the seismic damages of underground openings, and the use of rock mass classification systems in the ground support design, was conducted (Sections 6.3.4 and 6.4). This review provided some basis for determining the inputs and methodologies used in this analysis. Stability of the supported and unsupported emplacement and non-emplacement drifts was evaluated in this analysis. The excavation effects (i.e., state of the stress change due to excavation), thermal effects (i.e., due to heat output from waste packages), and seismic effects (i.e., from potential earthquake events) were evaluated, and stress controlled modes of failure were examined for two in situ stress conditions (k 0 =0.3 and 1.0) using rock properties representing rock mass categories of 1 and 5. Variation of rock mass units such as the non-lithophysal (Tptpmn) and lithophysal (Tptpll) was considered in the analysis. The focus was on the non-lithophysal unit because this unit appears to be relatively weaker and has much smaller joint spacing. Therefore, the drift stability and ground support needs were considered to be controlled by the design for this rock unit. The ground support systems for both emplacement and non-emplacement drifts were incorporated into the models to assess their performance under in situ, thermal, and seismic loading conditions. Both continuum and discontinuum modeling approaches were employed in the analyses of the rock mass behavior and in the evaluation of the

  10. Prospects of gold mineralization in the Gilgit-Baltistan Province of Pakistan

    Science.gov (United States)

    Shah, M. T.; Khan, S. D.; Tahirkheli, T.; Ahmad, L.; Miandad, S.; Rehman, A. U.; Ali, L.

    2012-12-01

    Gilgit-Baltistan province is the northern most province of Pakistan having its eastern, northern and western boarders with India, China and Afghanistan respectively. The geology of this province is unique as it has the spectacular tectonic entities of Asiatic plate (AP), Indian plate (IP) and the Kohistan-Ladakh arc (KLA). The Northern Suture Zone (NSZ) or Main Karakoram Thrust (MKT) separate the KLA from AP in the north while the Maim Mantle Thrust (MMT) separate the KLA from IP in the south. These different tectonic events have generated various types of igneous and metamorphic rocks in the form of gigantic mountain chains in the region. Considering the metallogenic provinces related to such types of tectonic environments world over, it can be suggested that the Gigit-Baltistan province may have the potential for the occurrence of economic mineral deposits. The present study is the follow-up of the previous studies for exploration of gold and base metals conducted by the Austrominerals and the Pakistan Mineral Development Corporation (PMDC) in the region. On the basis of PMDC extensive stream sediments geochemical survey of the province and delineated number of anomalous catchment areas for gold mineralization. In order to find the source bed-rock of gold, we have identified various alteration zones in these catchment areas by applying Remote sensing techniques by using both multispectral (LANDSAT, ASTER and Geoeye) and hyperspectral (Hyperion) data. Most of the alteration zones were found in steep high altitude inaccessible terrains. During this study, few of the accessible alteration zones in Golo Das, Bagrot valley, Shigri Bala, Machulu and Ranthak areas were selected for geological filed work and collection of proper samples from the alteration zones and host rocks for the identification of possible gold mineralization. In all these localities, the alteration zones are present along shear zones where the sulfide mineralization commonly occurs in the form of

  11. The Alto Paraguay Alkaline Province: petrographic, geochemical and geochronological characteristics

    International Nuclear Information System (INIS)

    Velazquez Fernandez, Victor

    1996-01-01

    The Alto Paraguay Province is located at the border of the State of Mato Grosso do Sul and Paraguay, between the coordinates 21 deg 10 ' to 23 deg 25 ' of Southern latitude and 57 deg 10 ' to 58 deg 00 ' , having the city of Porto Murtinho as the main reference point. The geotectonic domain of the area is governed by the precambric units of the Southern extreme of the Amazonic craton which developed a long and accentuated activity, giving rise to folds and important faults, that in several cases seem to have exerted an effective control of the magmatic manifestations. Radiometric data indicate that the emplacement of the syenitic bodies took place in the Permo-Triassic period, with a major incidence in the interval 260-240 Ma, representing thus, an important phase of alkaline magmatic affinity associated to the Parana Basin which is believed is to be unique, since the other known areas (Central, Amambay and Rio Apa Provinces, Paraguay, Velasco Province, Bolivia) are considerably younger (140-120 Ma). Syenitic rocks from the Alto Paraguay Province show wide variation in the ratio 87 Sr/ 86 Sr (0.703361 - 0.707734). Excluding the Cerro Boggiani rocks (0.703837-0.707734), values for the nepheline syenites (0.703361-0.703672) general lower than those of the other syenites types. Alkaline syenites cover the interval 0.703510- 0.703872, while quartz syenites and syenogranites are 0.704562 and 0.707076, respectively. geologic evidence, in addition to petrographic, geochemical and isotopic (Sr) data, suggest that the syenitic rocks have been derived from an unique mantelic parental liquid, by fractional crystallization and assimilation processes, which are assumed to be occurred during the emplacement of the magma in the crust. (author)

  12. Dynamic Mechanical Behavior of Dry and Water Saturated Igneous Rock with Acoustic Emission Monitoring

    Directory of Open Access Journals (Sweden)

    Jun Guo

    2018-01-01

    Full Text Available The uniaxial cyclic loading tests have been conducted to study the mechanical behavior of dry and water saturated igneous rock with acoustic emission (AE monitoring. The igneous rock samples are dried, naturally immersed, and boiled to get specimens with different water contents for the testing. The mineral compositions and the microstructures of the dry and water saturated igneous rock are also presented. The dry specimens present higher strength, fewer strains, and rapid increase of AE count subjected to the cyclic loading, which reflects the hard and brittle behavior and strong burst proneness of igneous rock. The water saturated specimens have lower peak strength, more accumulated strains, and increase of AE count during the cyclic loading. The damage of the igneous rocks with different water contents has been identified by the Felicity Ratio Analysis. The cyclic loading and unloading increase the dislocation between the mineral aggregates and the water-rock interactions further break the adhesion of the clay minerals, which jointly promote the inner damage of the igneous rock. The results suggest that the groundwater can reduce the burst proneness of the igneous rock but increase the potential support failure of the surrounding rock in igneous invading area. In addition, the results inspire the fact that the water injection method is feasible for softening the igneous rock and for preventing the dynamic disasters within the roadways and working faces located in the igneous intrusion area.

  13. Os, Nd and Sr isotope and trace element geochemistry of the Muli picrites: Insights into the mantle source of the Emeishan Large Igneous Province

    Science.gov (United States)

    Li, Jie; Xu, Ji-Feng; Suzuki, Katsuhiko; He, Bin; Xu, Yi-Gang; Ren, Zhong-Yuan

    2010-09-01

    A suite of picrites and basalts from the Muli area, in the northwestern part of the Emeishan continental flood basalt province, provides new and valuable information on the geochemistry of the Emeishan Large Igneous Province (LIP) and its source. The Muli picrites can be classified as type-1 or type-2. The former shows ocean-island basalt-like trace element characteristics, with γ Os (260 Ma) values and ɛ Nd (260 Ma) values ranging from + 7.5 to + 11.5 and from + 6.0 to + 7.8, respectively. This is the first time that picrites with highly radiogenic Os and high Os contents (up to 3.3 ppb) have been recognized in the Emeishan LIP. These characteristics probably reflect a relatively enriched component in the Emeishan LIP source. The type-2 picrites are characterized by non-radiogenic γ Os (260 Ma) values ranging from - 4.2 to - 0.3, and they may be further subdivided into type-2A and type-2B picrites. Type-2A picrites contain moderate amounts of the light rare earth elements (LREEs), have low Ce N/Yb N values (1.1-2.0), and a relatively high initial ɛ Nd (+ 5.0 to + 6.6). In terms of Os and Nd isotopes, the Muli type-2A picrites are similar to the Song Da komatiites of Vietnam and the Gorgona Island picrites, revealing the existence of a depleted mantle component in the Emeishan LIP source. In contrast with the type-2A picrites, type-2B lavas exhibit a negative Nb anomaly and relatively lower initial ɛ Nd and γ Os values (Nb/La > 1.8; ɛ Nd (260 Ma) = - 5.5 to + 6.4; γ Os (260 Ma) = - 4.2 to - 1.9), suggesting that the type-2B lavas have a depleted mantle source, similar to type-2A, but that the type-2B lavas are also influenced by various degrees of mixing of depleted plume-derived melt, sub-continental lithospheric mantle, and/or continental crust. Given that the basalts in the Muli area show similar geochemical features to those of the type-2B picrites, their origins are inferred to be similar.

  14. Concept of Operations for Waste Transport, Emplacement, and Retrieval

    International Nuclear Information System (INIS)

    Raczka, Norman T.

    2001-01-01

    The preparation of this technical report has two objectives. The first objective is to discuss the base case concepts of waste transport, emplacement, and retrieval operations and evaluate these operations relative to a lower-temperature repository design. Aspects of the operations involved in waste transport, emplacement and retrieval may be affected by the lower-temperature operating schemes. This report evaluates the effects the lower-temperature alternatives may have on the operational concepts involved in emplacing and retrieving waste. The second objective is to provide backup material for the design description, in a traceable and defensible format, for Section 2 of the Waste Emplacement/Retrieval System Description Document

  15. Duration of and decoupling between carbon isotope excursions during the end-Triassic mass extinction and Central Atlantic Magmatic Province emplacement

    Science.gov (United States)

    Yager, Joyce A.; West, A. Joshua; Corsetti, Frank A.; Berelson, William M.; Rollins, Nick E.; Rosas, Silvia; Bottjer, David J.

    2017-09-01

    Changes in δ13Ccarb and δ13Corg from marine strata occur globally in association with the end-Triassic mass extinction and the emplacement of the Central Atlantic Magmatic Province (CAMP) during the break up of Pangea. As is typical in deep time, the timing and duration of these isotopic excursions has remained elusive, hampering attempts to link carbon cycle perturbations to specific processes. Here, we report δ13Ccarb and δ13Corg from Late Triassic and Early Jurassic strata near Levanto, Peru, where intercalated dated ash beds permit temporal calibration of the carbon isotope record. Both δ13Ccarb and δ13Corg exhibit a broad positive excursion through the latest Triassic into the earliest Jurassic. The first order positive excursion in δ13Corg is interrupted by a negative shift noted in many sections around the world coincident with the extinction horizon. Our data indicate that the negative excursion lasts 85 ± 25 kyrs, longer than inferred by previous studies based on cyclostratigraphy. A 260 ± 80 kyr positive δ13Corg shift follows, during which the first Jurassic ammonites appear. The overall excursion culminates in a return to pre-perturbation carbon isotopic values over the next 1090 ± 70 kyrs. Via chronologic, isotopic, and biostratigraphic correlation to other successions, we find that δ13Ccarb and δ13Corg return to pre-perturbation values as CAMP volcanism ceases and in association with the recovery of pelagic and benthic biota. However, the initiation of the carbon isotope excursion at Levanto predates the well-dated CAMP sills from North America, indicating that CAMP may have started earlier than thought based on these exposures, or that the onset of carbon cycle perturbations was not related to CAMP.

  16. Geothermobarometry for ultramafic assemblages from the Emeishan Large Igneous Province, Southwest China and the Nikos and Zulu Kimberlites, Nunavut, Canada

    Science.gov (United States)

    Zhao, D.

    2009-05-01

    To understand and contrast the origins of ultramafic assemblages from basaltic and kimberlitic rocks and their associated deposits, such as V-Ti magnetite and Ni-Cu-(PGE) sulfide deposits and diamond, applicable thermobarometers were evaluated and applied to the ultramafic assemblages from the Emeishan Large Igneous Province (ELIP), Southwest China and from the Nikos and Zulu Kimberlites of Nunavut, Canada. The ELIP is located in the Yangtze Block, Southwest China and composed of Permian Emeishan Flood basalt (EFB) and associated layered mafic-ultramafic intrusions. Some of these intrusions host V-Ti magnetite deposits; while others contain Ni-Cu-(PGE) sulfide deposits. It is not clear why some intrusions host magnetite deposits and others contain sulfide deposits. The P-T conditions for the ultramafic assemblages from the mafic-ultramafic intrusions in the ELIP were calculated in order to understand the origins and the associated mineral deposits. The ultramafic assemblages are peridotite, olivine pyroxenite, pyroxenite in the layered intrusions and the common minerals include spinel, olivine, clinopyroxene, orthopyroxene, and minor magnetite and ilmenite. Using a two pyroxene thermometer and a Ca-Mg exchange barometer between olivine and clinopyroxene, a spinel-olivine-clinopyroxene-orthopyroxene assemblage from the Xinjie intrusion yields a T-P of 905°C and 17 kbar; and a similar assemblage from the Jinbaoshan intrusion yields a T-P of 1124°C and 31 kbar. The Nikos kimberlite, near Elwin Bay on Somerset Island, is located at the northeast end of the northeast-southwest kimberlite zone; and the Zulu kimberlite is located on the neighboring Brodeur Peninsula of Baffin Island, Nunavut. The ultramafic assemblages from the Canadian Kimberlites include garnet lherzolite, garnet-spinel lherzolite, spinel lherzolite, dunite, garnet websterite, spinel websterite and garnet clinopyroxenite. The calculated P-T conditions are in the range of 760 to 1180°C and 25 to 60

  17. DURATION OF GRANITOID MAGMATISM IN PERIPHERAL PARTS OF LARGE IGNEOUS PROVINCES (BASED ON 40AR/39AR ISOTOPIC STUDIES OF ALTAI PERMIAN-TRIASSIC GRANITOIDS

    Directory of Open Access Journals (Sweden)

    O. A. Gavryushkina

    2017-01-01

    Full Text Available In large igneous provinces (LIP of fold areas, granitoid rocks are dominant, while mantle-derivated rocks play a subordinate role in rock formation. If magma emissions are impulsive, it may take 25–30 million years for a LIP to form and take shape. In this paper, we present the results of 40Ar/39Ar isotopic studies of Permian-Triassic grani­toids in the Altai region, Russia, and clarify the evolution of this region located at the periphery of the Siberian LIP. These granitoids are very diverse and differ not only in their rock set, but also in the composition features. In the study region, the granodiorite-granite and granite-leucogranite association with the characteristics of I- and S-types as well rare metal ore-bearing leucogranites are observed along with gabbro- and syenite-granite series, including mafic and intermediate rocks with the A2-type geochemical features. The 40Ar/39Ar data obtained in our study suggest that most of the studied granitoids intruded within a short period of time, 254–247 Ma. This timeline is closely related to the formation of granitoids in theKuznetsk basin and dolerite dikes in the Terekta complex (251–248 and 255±5 Ma, respectively, as well as intrusions of lamproite and lamprophyre dikes of the Chuya complex (245–242 and 237–235 Ma. Thus, we conclude that the Altai Permian-Triassic granitoids are varied mainly due to the evolution of mafic magmatism.

  18. Review of potential subsurface permeable barrier emplacement and monitoring technologies

    International Nuclear Information System (INIS)

    Riggsbee, W.H.; Treat, R.L.; Stansfield, H.J.; Schwarz, R.M.; Cantrell, K.J.; Phillips, S.J.

    1994-02-01

    This report focuses on subsurface permeable barrier technologies potentially applicable to existing waste disposal sites. This report describes candidate subsurface permeable barriers, methods for emplacing these barriers, and methods used to monitor the barrier performance. Two types of subsurface barrier systems are described: those that apply to contamination.in the unsaturated zone, and those that apply to groundwater and to mobile contamination near the groundwater table. These barriers may be emplaced either horizontally or vertically depending on waste and site characteristics. Materials for creating permeable subsurface barriers are emplaced using one of three basic methods: injection, in situ mechanical mixing, or excavation-insertion. Injection is the emplacement of dissolved reagents or colloidal suspensions into the soil at elevated pressures. In situ mechanical mixing is the physical blending of the soil and the barrier material underground. Excavation-insertion is the removal of a soil volume and adding barrier materials to the space created. Major vertical barrier emplacement technologies include trenching-backfilling; slurry trenching; and vertical drilling and injection, including boring (earth augering), cable tool drilling, rotary drilling, sonic drilling, jetting methods, injection-mixing in drilled holes, and deep soil mixing. Major horizontal barrier emplacement technologies include horizontal drilling, microtunneling, compaction boring, horizontal emplacement, longwall mining, hydraulic fracturing, and jetting methods

  19. Application of air hammer drilling technology in igneous rocks of Junggar basin

    Science.gov (United States)

    Zhao, Hongshan; Feng, Guangtong; Yu, Haiye

    2018-03-01

    There were many technical problems such as serious well deviation, low penetration rate and long drilling cycle in igneous rocks because of its hardness, strong abrasive and poor drillability, which severely influenced the exploration and development process of Junggar basin. Through analyzing the difficulties of gas drilling with roller bits in Well HS 2, conducting the mechanics experiments about igneous rock, and deeply describing the rock-breaking mechanism of air hammer drilling and its adaptability in igneous rocks, air hammer drilling can realize deviation control and fast drilling in igneous rocks of piedmont zone and avoid the wear and fatigue fracture of drilling strings due to its characteristics of low WOB, low RPM and high frequency impact. Through firstly used in igneous rocks of Well HS 201, compared with gas drilling with cone bit, the average penetration rate and one-trip footage of air hammer drilling respectively increased by more than 2.45 times and 6.42 times while the well deviation was always controlled less than 2 degrees. Two records for Block HS were set up such as the fastest penetration rate of 14.29m/h in Φ444.5mm well hole and the highest one-trip footage of 470.62m in Φ311.2mm well hole. So air hammer drilling was an effective way to realize optimal and fast drilling in the igneous rock formation of Junggar basin.

  20. Peridotites and mafic igneous rocks at the foot of the Galicia Margin: an oceanic or continental lithosphere? A discussion

    Energy Technology Data Exchange (ETDEWEB)

    Korprobst, J.; Chazot, G.

    2016-10-01

    An ultramafic/mafic complex is exposed on the sea floor at the foot of the Galicia Margin (Spain and Portugal). It comprises various types of peridotites and pyroxenites, as well as amphibole-diorites, gabbros, dolerites and basalts. For chronological and structural reasons (gabbros were emplaced within peridotites before the continental break-up) this unit cannot be assigned to the Atlantic oceanic crust. The compilation of all available petrological and geochemical data suggests that peridotites are derived from the sub-continental lithospheric mantle, deeply transformed during Cretaceous rifting. Thus, websterite dykes extracted from the depleted MORB mantle reservoir (DMM), were emplaced early within the lithospheric harzburgites; subsequent boudinage and tectonic dispersion of these dykes in the peridotites, during deformation stages at the beginning of rifting, resulted in the formation of fertile but isotopically depleted lherzolites. Sterile but isotopically enriched websterites, would represent melting residues in the peridotites, after significant partial melting and melt extraction related to the thermal erosion of the lithosphere. The latter melts are probably the source of brown amphibole metasomatic crystallization in some peridotites, as well as of the emplacement of amphibole-diorite dykes. Melts directly extracted from the asthenosphere were emplaced as gabbro within the sub-continental mantle. Mixing these DMM melts together with the enriched melts extracted from the lithosphere, provided the intermediate isotopic melt-compositions - in between the DMM and Oceanic Islands Basalts reservoir - observed for the dolerites and basalts, none of which are characterized by a genuine N-MORB signature. An enriched lithospheric mantle, present prior to rifting of the Galicia margin, is in good agreement with data from the Messejana dyke (Portugal) and more generally, with those of all continental tholeiites of the Central Atlantic Magmatic Province (CAMP

  1. Aspects of igneous activity significant to a repository at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Krier, D.J.; Perry, F.V.

    2004-01-01

    Location, timing, volume, and eruptive style of post-Miocene volcanoes have defined the volcanic hazard significant to a proposed high-level radioactive waste (HLW) and spent nuclear fuel (SNF) repository at Yucca Mountain, Nevada, as a low-probability, high-consequence event. Examination of eruptive centers in the region that may be analogueues to possible future volcanic activity at Yucca Mountain have aided in defining and evaluating the consequence scenarios for intrusion into and eruption above a repository. The probability of a future event intersecting a repository at Yucca Mountain has a mean value of 1.7 x 10 -8 per year. This probability comes from the Probabilistic Volcanic Hazard Assessment (PVHA) completed in 1996 and updated to reflect change in repository layout. Since that time, magnetic anomalies representing potential buried volcanic centers have been identified fiom magnetic surveys; however these potential buried centers only slightly increase the probability of an event intersecting the repository. The proposed repository will be located in its central portion of Yucca Mountain at approximately 300m depth. The process for assessing performance of a repository at Yucca Mountain has identified two scenarios for igneous activity that, although having a very low probability of occurrence, could have a significant consequence should an igneous event occur. Either a dike swarm intersecting repository drifts containing waste packages, or a volcanic eruption through the repository could result in release of radioactive material to the accessible environment. Ongoing investigations are assessing the mechanisms and significance of the consequence scenarios. Lathrop Wells Cone (∼80,000 yrs), a key analogue for estimating potential future volcanic activity, is the youngest surface expression of apparent waning basaltic volcanism in the region. Cone internal structure, lavas, and ash-fall tephra have been examined to estimate eruptive volume, eruption

  2. Supervolcanoes within an ancient volcanic province in Arabia Terra, Mars.

    Science.gov (United States)

    Michalski, Joseph R; Bleacher, Jacob E

    2013-10-03

    Several irregularly shaped craters located within Arabia Terra, Mars, represent a new type of highland volcanic construct and together constitute a previously unrecognized Martian igneous province. Similar to terrestrial supervolcanoes, these low-relief paterae possess a range of geomorphic features related to structural collapse, effusive volcanism and explosive eruptions. Extruded lavas contributed to the formation of enigmatic highland ridged plains in Arabia Terra. Outgassed sulphur and erupted fine-grained pyroclastics from these calderas probably fed the formation of altered, layered sedimentary rocks and fretted terrain found throughout the equatorial region. The discovery of a new type of volcanic construct in the Arabia volcanic province fundamentally changes the picture of ancient volcanism and climate evolution on Mars. Other eroded topographic basins in the ancient Martian highlands that have been dismissed as degraded impact craters should be reconsidered as possible volcanic constructs formed in an early phase of widespread, disseminated magmatism on Mars.

  3. Longevity of Emplacement Drift Ground Support Materials, Rev. 01

    International Nuclear Information System (INIS)

    David H. Tang

    2000-01-01

    The purpose of this analysis is to evaluate the factors affecting the longevity of emplacement drift ground support materials and to develop a basis for the selection of materials for ground support that will function throughout the preclosure period of a potential repository at Yucca Mountain. The Development Plan (DP) for this analysis is given in Longevity of Emplacement Drift Ground Support Materials (CRWMS M and O 1999a). The objective of this analysis is to update the previous analysis (CRWMS M and O 2000a) to account for related changes in the Ground Control System Description Document (CRWMS M and O 2000b), the Monitored Geologic Repository Project Description Document (CRWMS M and O 1999b), and in environmental conditions, and to provide updated information on candidate ground support materials. Candidate materials for ground support are carbon steel and cement grout. Steel is mainly used for steel sets, lagging, channel, rock bolts, and wire mesh. Cement grout is only considered in the case of grouted rock bolts. Candidate materials for the emplacement drift invert are carbon steel and crushed rock ballast. Materials are evaluated for the repository emplacement drift environment based on the updated thermal loading condition and waste package design. The analysis consists of the following tasks: (1) Identify factors affecting the longevity of ground support materials for use in emplacement drifts; (2) Review existing documents concerning the behavior of candidate ground support materials during the preclosure period; (3) Evaluate impacts of temperature and radiation effects on mechanical and thermal properties of steel. Assess corrosion potential of steel at emplacement drift environment; (4) Evaluate factors affecting longevity of cement grouts for fully grouted rock bolt system. Provide updated information on cement grout mix design for fully grouted rock bolt system; and (5) Evaluate longevity of materials for the emplacement drift invert

  4. Rock burst governance of working face under igneous rock

    Science.gov (United States)

    Chang, Zhenxing; Yu, Yue

    2017-01-01

    As a typical failure phenomenon, rock burst occurs in many mines. It can not only cause the working face to cease production, but also cause serious damage to production equipment, and even result in casualties. To explore how to govern rock burst of working face under igneous rock, the 10416 working face in some mine is taken as engineering background. The supports damaged extensively and rock burst took place when the working face advanced. This paper establishes the mechanical model and conducts theoretical analysis and calculation to predict the fracture and migration mechanism and energy release of the thick hard igneous rock above the working face, and to obtain the advancing distance of the working face when the igneous rock fractures and critical value of the energy when rock burst occurs. Based on the specific conditions of the mine, this paper put forward three kinds of governance measures, which are borehole pressure relief, coal seam water injection and blasting pressure relief.

  5. Emplacement of the La Peña alkaline igneous complex, Mendoza, Argentina (33° S): Implications for the early Miocene tectonic regime in the retroarc of the Andes

    Science.gov (United States)

    Pagano, D. S.; Galliski, M. A.; Márquez-Zavalía, M. F.

    2014-03-01

    The La Peña alkaline complex (LPC) of Miocene age (18-19 Ma) lies on the eastern front of the Precordillera (32°41ʹ34ʺS, 68°59ʹ48″W, 1400-2900 m a.s.l.), 30 km northwest of Mendoza city, Argentina. It is a subcircular massif of 19 km2 and 5 km in diameter, intruded in the metasedimentary sequence of the Villavicencio Formation of Silurian-Devonian age. It is the result of integration of multiple pulses derived from one or more deep magma chambers, which form a suite of silicate rocks grouped into: a clinopyroxenite body, a central syenite facies with a large breccia zone at the contact with the clinopyroxenite, bodies of malignite, trachyte and syenite porphyry necks, and a system of radial and annular dikes of different compositions. Its subcircular geometry and dike system distribution are frequent features of intraplate plutons or plutons emplaced in post-orogenic settings. These morphostructural features characterize numerous alkaline complexes worldwide and denote the importance of magmatic pressures that cause doming with radial and annular fracturing, in a brittle country rock. However, in the LPC, the attitude of the internal fabric of plutonic and subvolcanic units and the preferential layout of dikes match the NW-SE extensional fractures widely distributed in the host rock. This feature indicates a strong tectonic control linked to the structure that facilitate space for emplacement, corresponding to the brittle shear zone parallel to the N-S stratigraphy of the country rock. Shearing produced a system of discontinuities, with a K fractal fracture pattern, given by the combination of Riedel (R), anti-Riedel (R‧), (P) and extensional (T) fracture systems, responsible for the control of melt migration by the opening of various fracture branches, but particularly through the NW-SE (T) fractures. Five different pulses would have ascent, (1) an initial one from which cumulate clinopyroxenite was formed, (2) a phase of mafic composition represented by

  6. Thermal effects of the Santa Eulália Plutonic Complex (southern Portugal on the meta-igneous and metasedimentary host rocks

    Directory of Open Access Journals (Sweden)

    Cruz, C.

    2014-12-01

    Full Text Available The Santa Eulália Plutonic Complex (SEPC is a late-Variscan granitic body located in the northern part of the Ossa Morena Zone, a inner zone of the Variscan Iberian Massif. The SEPC host rocks are composed of meta-igneous and metasedimentary units, from Upper Proterozoic to Paleozoic ages, with a NW-SE structure, cross-cut by the SEPC. The SEPC host rocks, with low grade metamorphism show well preserved primary sedimentary or igneous mineralogical, textural and structural features. The thermal effect induced by the SEPC is restricted to the roof pendants. At N and NE of the SEPC, textures and paragenesis resulting from thermal metamorphism, are not related to the SEPC intrusion but to a previous magmatism, controlled by the NW-SE regional anisotropies. The restriction of the thermal effects to the pluton roof may be caused by a combination of several interrelated factors: higher volume of granitic mass, thermal effect by advection of fluids and longer period of prevalence of high thermal conditions. The geochemical study of SEPC host rocks shows the heterogeneous character and diversity of metasedimentary, igneous and meta-igneous rocks. The whole rock geochemical data indicate that all the metasedimentary lithologies derived from an upper continental crustal source and the igneous and meta-igneous rocks show no evidence of metasomatic effects by the SEPC emplacement.El Complejo Plutónico de Santa Eulalia (CPSE es un cuerpo granítico tardi-Varisco situado en la parte norte de la Zona de Ossa Morena, en la zona interior del Macizo Ibérico Varisco. Las rocas encajantes del CPSE están compuestas por unidades meta-ígneas y metasedimentarias, de edades que van desde el Proterozoico Superior hasta el Paleozoico, con una estructura de dirección NW-SE, cortada por el CPSE. Las rocas encanjantes del CPSE, con metamorfismo de bajo grado conservan estructuras, mineralogía y textura primarias. El efecto térmicoinducido por el CPSE se limita a los

  7. Petrogenesis of Igneous-Textured Clasts in Martian Meteorite Northwest Africa 7034

    Science.gov (United States)

    Santos, A. R.; Agee, C. B.; Humayun, M.; McCubbin, F. M.; Shearer, C. K.

    2016-01-01

    The martian meteorite Northwest Africa 7034 (and pairings) is a breccia that samples a variety of materials from the martian crust. Several previous studies have identified multiple types of igneous-textured clasts within the breccia [1-3], and these clasts have the potential to provide insight into the igneous evolution of Mars. One challenge presented by studying these small rock fragments is the lack of field context for this breccia (i.e., where on Mars it formed), so we do not know how many sources these small rock fragments are derived from or the exact formation his-tory of these sources (i.e., are the sources mantle de-rived melt or melts contaminated by a meteorite impactor on Mars). Our goal in this study is to examine specific igneous-textured clast groups to determine if they are petrogenetically related (i.e., from the same igneous source) and determine more information about their formation history, then use them to derive new insights about the igneous history of Mars. We will focus on the basalt clasts, FTP clasts (named due to their high concentration of iron, titanium, and phosphorous), and mineral fragments described by [1] (Fig. 1). We will examine these materials for evidence of impactor contamination (as proposed for some materials by [2]) or mantle melt derivation. We will also test the petrogenetic models proposed in [1], which are igneous processes that could have occurred regardless of where the melt parental to the clasts was formed. These models include 1) derivation of the FTP clasts from a basalt clast melt through silicate liquid immiscibility (SLI), 2) derivation of the FTP clasts from a basalt clast melt through fractional crystallization, and 3) a lack of petrogenetic relationship between these clast groups. The relationship between the clast groups and the mineral fragments will also be explored.

  8. Decoupling of Mg-C and Sr-Nd-O isotopes traces the role of recycled carbon in magnesiocarbonatites from the Tarim Large Igneous Province

    Science.gov (United States)

    Cheng, Zhiguo; Zhang, Zhaochong; Hou, Tong; Santosh, M.; Chen, Lili; Ke, Shan; Xu, Lijuan

    2017-04-01

    The Tarim Large Igneous Province in NW China hosts numerous magmatic carbonatite dikes along its northern margin. The carbonatites are composed mainly of dolomite (90 vol.%) and minor calcite (5 vol.%), with apatite, barite, celestine, aegirine, monazite and bastnaesite as accessory minerals. The rocks correspond to magnesiocarbonatites with a compositional range of 13.73-19.59 wt.% MgO, and 20.03-30.11 wt.% CaO, along with 1.65-3.31 wt.% total Fe2O3, 0.02-2.39 wt.% SiO2 and other minor elements, such as P2O5, Na2O and K2O. These magnesiocarbonatites are characterized by extreme enrichment in incompatible elements with high total rare earth element (REE) contents of 372-36965 ppm. The strontium [(87Sr/86Sr)i = 0.70378-0.70386], neodymium [εNd(t) = +2.51 - +3.59] and oxygen (δ18OV-SMOW = 5.9‰-8.0‰) isotope values of these rocks are consistent with a mantle origin, whereas the magnesium (δ26Mg = -1.09‰ to -0.85‰) and carbon (δ13CV-PDB = -4.1‰ to -5.9‰) isotopes are decoupled from mantle values and reflect signature of recycled sedimentary carbonates. Global plate tectonic models predict that sedimentary carbonates in convergent margins are subducted to deep domains in the mantle, with phase transitions from calcite/dolomite to magnesite, and eventually to periclase/perovskite. The involvement of a mantle plume enhances the normal mantle geotherms and promotes decomposition reactions of magnesite. The decoupling of Mg-C and Sr-Nd-O isotopes in the mangesiocarbonatites provides insights on the origin of carbonatites, and also illustrates a case of interaction between mantle plume and subduction-related components.

  9. Longevity of Emplacement Drift Ground Support Materials

    International Nuclear Information System (INIS)

    D.H.Tang

    2001-01-01

    The purpose of this analysis is to evaluate the factors affecting the longevity of emplacement drift ground support materials and to develop a basis for the selection of materials for ground support that will function throughout the preclosure period of a potential repository at Yucca Mountain. REV 01 ICN 01 of this analysis is developed in accordance with AP-3.10Q, Analyses and Models, Revision 2, ICN 4, and prepared in accordance with the Technical Work Plan for Subsurface Design Section FY 01 Work Activities (CRWMS M and O 2001a). The objective of this analysis is to update the previous analysis (CRWMS M and O 2000a) to account for related changes in the Ground Control System Description Document (CRWMS M and O 2000b), the Monitored Geologic Repository Project Description Document, which is included in the Requirements and Criteria for Implementing a Repository Design that can be Operated Over a Range of Thermal Modes (BSC 2001), input information, and in environmental conditions, and to provide updated information on candidate ground support materials. Candidate materials for ground support are carbon steel and cement grout. Steel is mainly used for steel sets, lagging, channel, rock bolts, and wire mesh. Cement grout is only considered in the case of grouted rock bolts. Candidate materials for the emplacement drift invert are carbon steel and granular natural material. Materials are evaluated for the repository emplacement drift environment based on the updated thermal loading condition and waste package design. The analysis consists of the following tasks: (1) Identify factors affecting the longevity of ground support materials for use in emplacement drifts. (2) Review existing documents concerning the behavior of candidate ground support materials during the preclosure period. (3) Evaluate impacts of temperature and radiation effects on mechanical and thermal properties of steel. Assess corrosion potential of steel at emplacement drift environment. (4

  10. WIPP waste package testing on simulated DHLW: emplacement

    International Nuclear Information System (INIS)

    Molecke, M.A.

    1984-01-01

    Several series of simulated (nonradioactive) defense high-level waste (DHLW) package tests have been emplaced in the WIPP, a research and development facility authorized to demonstrate the safe disposal of defense-related wastes. The primary purpose of these 3-to-7 year duration tests is to evaluate the in situ materials performance of waste package barriers (canisters, overpacks, backfills, and nonradioactive DHLW glass waste form) for possible future application to a licensed waste repository in salt. This paper describes all test materials, instrumentation, and emplacement and testing techniques, and discusses progress of the various tests. These tests are intended to provide information on materials behavior (i.e., corrosion, metallurgical and geochemical alterations, waste form durability, surface interactions, etc.), as well as comparison between several waste package designs, fabrications details, and actual costs. These experiments involve 18 full-size simulated DHLW packages (approximately 3.0 m x 0.6 m diameter) emplaced in vertical boreholes in the salt drift floor. Six of the test packages contain internal electrical heaters (470 W/canister), and were emplace under approximately reference DHLW repository conditions. Twelve other simulated DHLW packages were emplaced under accelerated-aging or overtest conditions, including the artificial introduction of brine, and a thermal loading approximately three to four times higher than reference. Eight of these 12 test packages contain 1500 W/canister electrical heaters; the other four are filled with DHLW glass. 9 refs., 1 fig

  11. Towards a comprehensive classification of igneous rocks and magmas

    Science.gov (United States)

    Middlemost, Eric A. K.

    1991-08-01

    The IUGS Subcommission on the Systematics of Igneous Rocks has recently published an excellent book on the classification of these rocks. This event has shifted the vexed question of classification towards the top of the agenda in igneous petrology. Over the years the Subcommission has used many different criteria to establish the positions of the boundaries between the various common igneous rocks. It now has to adopt a holistic approach and develop a comprehensive, coherent classification that is purged of all the minor anomalies that arise between the various classifications that it has approved. It is appreciated that the Subcommission's classification was never intended to have any genetic implications; however, it is suggested that an ideal classification should he presented in such a way that it is able to group rocks into an order that directs attention to petrogenetic relationships between individual rocks and larger groups of rocks. Unfortunately, many of the Subcommission's definitions are Earth chauvinistic; for example, igneous rocks are defined as being those rocks that solidified from a molten state either within or on the surface of the Earth. Nowhere in the book is it acknowledged that during the past 20 years, while the Subcommission has been framing its many recommendations, a whole new science of planetary petrology has subsumed classical petrology. In any new edition of the book, the Subcommission should acknowledge that rocks are essentially the solid materials of which planets, natural satellites and other broadly similar cosmic bodies are made. The Subcommission should also explicitly recognise that igneous rocks can be divided into either a main sequence of essentially common rocks or a number of supplementary clans of special rocks that evolved outside the main sequence. It is hoped that in the near future the Subcommission will rescind its recommendation that the TAS classification should be regarded as an adjunct to its more traditional

  12. 40Ar/39Ar studies of deep sea igneous rocks

    International Nuclear Information System (INIS)

    Seidemann, D.

    1978-01-01

    An attempt to date deep-sea igneous rocks reliably was made using the 40 Ar/ 39 Ar dating technique. It was determined that the 40 Ar/ 39 Ar incremental release technique could not be used to eliminate the effects of excess radiogenic 40 Ar in deep-sea basalts. Excess 40 Ar is released throughout the extraction temperature range and cannot be distinguished from 40 Ar generated by in situ 40 K decay. The problem of the reduction of K-Ar dates associated with sea water alteration of deep-sea igneous rocks could not be resolved using the 40 Ar/ 39 Ar technique. Irradiation induced 39 Ar loss and/or redistribution in fine-grained and altered igneous rocks results in age spectra that are artifacts of the experimental procedure and only partly reflect the geologic history of the sample. Therefore, caution must be used in attributing significance to age spectra of fine grained and altered deep-sea igneous rocks. Effects of 39 Ar recoil are not important for either medium-grained (or coarser) deep-sea rocks or glasses because only a small fraction of the 39 Ar recoils to channels of easy diffusion, such as intergranular boundaries or cracks, during the irradiation. (author)

  13. 40Ar/39Ar geochronology of hypabyssal igneous rocks in the Maranon Basin of Peru - A record of thermal history, structure, and alteration

    Science.gov (United States)

    Prueher, L.M.; Erlich, R.; Snee, L.W.

    2005-01-01

    Hypabyssal andesites and dacites from the Balsapuerto Dome in the Mara?on Basin of Peru record the thermal, tectonic, and alteration history of the area. The Mara?on Basin is one of 19 sub-Andean foreland basins. The hypabyssal rocks in the Balsapuerto Dome are one of four known occurrences of subvolcanic rocks along the deformation front in Peru. This dome is a potential petroleum structural trap. Petroleum seeps near the dome indicate that a source for the petroleum is present, but the extent and amount of petroleum development is unknown. The Balsapuerto hypabyssal rocks are plagioclase-, hornblende-, pyroxene-phyric andesites to dacites. Some parts of the dome are pervasively altered to a hydrothermal assemblage of quartz-sericite-pyrite. 40Ar/39Ar geochronology shows that thermal activity related to emplacement of these subvolcanic rocks took place between 12-10 Ma, subsequent to the major periods of Andean folding and faulting, previously assumed to have occurred about 9 Ma. Eleven argon mineral age-spectrum analyses were completed. Argon apparent ages on amphibole range from 12.7 to 11.6 Ma, and the age spectra are simple, which indicates that the ages are very close to emplacement ages. Potassium feldspar yields an argon age spectrum ranging in age from 12.5 to 11.4 Ma, reflecting the period during which the potassium feldspar closed to argon diffusion between the temperature range of 350?C to about 150?C; thus the potassium feldspar age spectrum reflects a cooling profile throughout this temperature range. This age range is consistent with ages of emplacement for the entire igneous complex indicating that an increased thermal state existed in the area for at least 1.0 m.y. Combined with the coexisting hornblende age, this rock cooled from ~580?C to ~150?C in ~1.2 m.y. resulting in an average cooling rate of 358?C /m.y. White mica, or sericite, formed as a later alteration phase associated with quartz- sericite- pyrite and propylitic alteration in some

  14. The Sonju Lake layered intrusion, northeast Minnesota: Internal structure and emplacement history inferred from magnetic fabrics

    Science.gov (United States)

    Maes, S.M.; Tikoff, B.; Ferre, E.C.; Brown, P.E.; Miller, J.D.

    2007-01-01

    The Sonju Lake intrusion (SLI), in northeastern Minnesota, is a layered mafic complex of Keweenawan age (1096.1 ?? 0.8 Ma) related to the Midcontinent rift. The cumulate paragenesis of the intrusion is recognized as broadly similar to the Skaergaard intrusion, a classic example of closed-system differentiation of a tholeiitic mafic magma. The SLI represents nearly closed-system differentiation through bottom-up fractional crystallization. Geochemical studies have identified the presence of a stratabound, 50-100 m thick zone anomalously enriched in Au + PGE. Similar to the PGE reefs of the Skaergaard intrusion, this PGE-enriched zone is hosted within oxide gabbro cumulates, about two-third of the way up from the base of the intrusion. We present a petrofabric study using the anisotropy of magnetic susceptibility (AMS) to investigate the emplacement and flow patterns within the Sonju Lake intrusion. Petrographic and electron microprobe studies, combined with AMS and hysteresis measurements indicate the primary source of the magnetic signal is pseudo-single domain (PSD) magnetite or titanomagnetite. Low field AMS was measured at 32 sites within the Sonju Lake intrusion, which provided information about primary igneous fabrics. The magnetic fabrics in the layered series of the Sonju Lake intrusion are consistent with sub-horizontal to inclined emplacement of the intrusion and show evidence that the cumulate layers were deposited in a dynamic environment. Well-aligned magnetic lineations, consistently plunging shallowly toward the southwest, indicate the source of the magma is a vertical sill-like feeder, presumably located beneath the Finland granite. The Finland granite acted as a density trap for the Sonju Lake magmas, forcing lateral flow of magma to the northeast. The strongly oblate magnetic shape fabrics indicate the shallowly dipping planar fabrics were enhanced by compaction of the crystal mush. ?? 2007 Elsevier B.V. All rights reserved.

  15. Permian charnockites in the Pobeda area: Implications for Tarim mantle plume activity and HT metamorphism in the South Tien Shan range

    Science.gov (United States)

    Loury, Chloé; Rolland, Yann; Lanari, Pierre; Guillot, Stéphane; Bosch, Delphine; Ganino, Clément; Jourdon, Anthony; Petit, Carole; Gallet, Sylvain; Monié, Patrick; Riel, Nicolas

    2018-04-01

    The Permian history of the Central Asian Orogenic belt is marked by large-scale strike-slip faults that reactivate former Paleozoic structures, delineated by widespread alkaline magmatism. The genetic link between the syn-kinematic granitoids emplaced in the Tien Shan range and magmas emplaced within the Tarim Large Igneous Province, and the interaction between this plume and transcurrent tectonics, are still unsolved issues. We investigated the Pobeda massif, in the eastern Kyrgyz Tien Shan, located at the boundary between the Tien Shan range and the Tarim Craton, which exhibits a high-temperature unit. In this unit, Permian magmatism resulted in the emplacement of alkaline charnockites at mid-crustal levels. The primary mineralogical assemblage is nominally anhydrous and made of ortho- and clino-pyroxenes, fayalite, K-feldspar, plagioclase and quartz. These charnockites are associated with partially-molten paragneisses and marbles. Thermobarometry on these rocks indicates that the charnockites emplaced following the intrusion of a melt at a temperature > 1000 °C and pressure of around 6 kbar, corresponding to depth of 20 km. The resulting thermal anomaly triggered the partial melting of paragneisses. Bulk geochemistry including Sr, Nd, Pb and Hf isotopes suggests that charnockites fit into the Tarim Large Igneous Province magmatic series, with minor crustal assimilation. U-Pb ages on zircons of charnockites and surrounding paragneisses indicate that charnockites intruded and triggered partial melting of the gneisses at c. 287, 275 and 265 Ma. 40Ar/39Ar dating on amphibole gives a similar age as the U-Pb age at 276.2 ± 2.0 Ma. 40Ar/39Ar dating on biotite from the Charnockite unit marbles gives ages at ca. 256-265 Ma, which shows that exhumation onset directly follows the HT history, and is tentatively correlated to top-to-the-North thrusting of the Charnockite unit in a transpressive context. Additional 40Ar/39Ar dating on syn-kinematic white micas from an

  16. Handling and Emplacement Options for Deep Borehole Disposal Conceptual Design.

    Energy Technology Data Exchange (ETDEWEB)

    Cochran, John R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hardin, Ernest [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-07-01

    This report presents conceptual design information for a system to handle and emplace packages containing radioactive waste, in boreholes 16,400 ft deep or possibly deeper. Its intended use is for a design selection study that compares the costs and risks associated with two emplacement methods: drill-string and wireline emplacement. The deep borehole disposal (DBD) concept calls for siting a borehole (or array of boreholes) that penetrate crystalline basement rock to a depth below surface of about 16,400 ft (5 km). Waste packages would be emplaced in the lower 6,560 ft (2 km) of the borehole, with sealing of appropriate portions of the upper 9,840 ft (3 km). A deep borehole field test (DBFT) is planned to test and refine the DBD concept. The DBFT is a scientific and engineering experiment, conducted at full-scale, in-situ, without radioactive waste. Waste handling operations are conceptualized to begin with the onsite receipt of a purpose-built Type B shipping cask, that contains a waste package. Emplacement operations begin when the cask is upended over the borehole, locked to a receiving flange or collar. The scope of emplacement includes activities to lower waste packages to total depth, and to retrieve them back to the surface when necessary for any reason. This report describes three concepts for the handling and emplacement of the waste packages: 1) a concept proposed by Woodward-Clyde Consultants in 1983; 2) an updated version of the 1983 concept developed for the DBFT; and 3) a new concept in which individual waste packages would be lowered to depth using a wireline. The systems described here could be adapted to different waste forms, but for design of waste packaging, handling, and emplacement systems the reference waste forms are DOE-owned high- level waste including Cs/Sr capsules and bulk granular HLW from fuel processing. Handling and Emplacement Options for Deep Borehole Disposal Conceptual Design July 23, 2015 iv ACKNOWLEDGEMENTS This report has

  17. Intense and widespread seismicity during the end-Triassic mass extinction due to emplacement of a large igneous province

    DEFF Research Database (Denmark)

    Lindström, Sofie; Pedersen, Gunver Krarup; Schootbrugge, Bas van de

    2015-01-01

    Multiple levels of earthquake-induced soft-sediment deformations (seismites) are concentrated in the end-Triassic mass extinction interval across Europe. The repetitive nature of the seismites rules out an origin by an extraterrestrial impact. Instead, this intense seismic activity is linked...

  18. Emplacement and stemming of nuclear explosives for Plowshare applications

    Energy Technology Data Exchange (ETDEWEB)

    Cramer, J L [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

    1970-05-15

    This paper will discuss the various methods used for emplacement and design considerations that must be taken into account when the emplacement and stemming method is selected. The step-by-step field procedure will not be discussed in this paper. The task of emplacing and stemming the nuclear explosive is common to all Plowshare experiments today. All present-day applications of a nuclear explosive for Plowshare experiments require that the detonation take place some distance below the surface of the ground. This is normally done by lowering the explosive into an emplacement hole to a desired depth and then backfilling the hole with a suitable stemming material. At first glance it scenes like a very straightforward, simple task to perform. It would appear to be a task that could become a standard procedure for all experiments; however, this is not the case. In actuality, the emplacement and stemming of a nuclear explosive must almost be a custom design. It varies with the application of the experiment, i.e., cratering or underground engineering. It also varies with the condition of the hole, the available equipment to do the job, the actual purpose of the stemming, possible postshot reentry, hydrology, geology, and future production. A very important item that must always be considered is the protection of the firing and signal cables during the downhole and stemming operation. Each of these things must be considered; ignoring any one of them could jeopardize one of the objectives of the experiment or perhaps even the experiment itself. It should be emphasized that for a multiple-shot program such as would be used to develop a gas field where the geology, depths of burial etc. are the same, the emplacement and stemming operation would be standardized, as would all other parts of the program. However, for individual experiments in totally different areas, complete standardization of the emplacement and stemming is impossible.

  19. Emplacement and stemming of nuclear explosives for Plowshare applications

    International Nuclear Information System (INIS)

    Cramer, J.L.

    1970-01-01

    This paper will discuss the various methods used for emplacement and design considerations that must be taken into account when the emplacement and stemming method is selected. The step-by-step field procedure will not be discussed in this paper. The task of emplacing and stemming the nuclear explosive is common to all Plowshare experiments today. All present-day applications of a nuclear explosive for Plowshare experiments require that the detonation take place some distance below the surface of the ground. This is normally done by lowering the explosive into an emplacement hole to a desired depth and then backfilling the hole with a suitable stemming material. At first glance it scenes like a very straightforward, simple task to perform. It would appear to be a task that could become a standard procedure for all experiments; however, this is not the case. In actuality, the emplacement and stemming of a nuclear explosive must almost be a custom design. It varies with the application of the experiment, i.e., cratering or underground engineering. It also varies with the condition of the hole, the available equipment to do the job, the actual purpose of the stemming, possible postshot reentry, hydrology, geology, and future production. A very important item that must always be considered is the protection of the firing and signal cables during the downhole and stemming operation. Each of these things must be considered; ignoring any one of them could jeopardize one of the objectives of the experiment or perhaps even the experiment itself. It should be emphasized that for a multiple-shot program such as would be used to develop a gas field where the geology, depths of burial etc. are the same, the emplacement and stemming operation would be standardized, as would all other parts of the program. However, for individual experiments in totally different areas, complete standardization of the emplacement and stemming is impossible

  20. Identification of igneous rocks in a superimposed basin through integrated interpretation dominantly based on magnetic data

    Science.gov (United States)

    LI, S.

    2017-12-01

    Identification of igneous rocks in the basin environment is of great significance to the exploration for hydrocarbon reservoirs hosted in igneous rocks. Magnetic methods are often used to alleviate the difficulties faced by seismic imaging in basins with thick cover and complicated superimposed structures. We present a case study on identification of igneous rocks in a superimposed basin through integrated interpretation based on magnetic and other geophysical data sets. The study area is located in the deepest depression with sedimentary cover of 14,000 m in Huanghua basin, which is a Cenozoic basin superimposed on a residual pre-Cenozoic basin above the North China craton. Cenozoic and Mesozoic igneous rocks that are dominantly intermediate-basic volcanic and intrusive rocks are widespread at depth in the basin. Drilling and seismic data reveal some volcanic units and intrusive rocks in Cenozoic stratum at depths of about 4,000 m. The question remains to identify the lateral extent of igneous rocks in large depth and adjacent areas. In order to tackle the difficulties for interpretation of magnetic data arisen from weak magnetic anomaly and remanent magnetization of igneous rocks buried deep in the superimposed basin, we use the preferential continuation approach to extract the anomaly and magnetic amplitude inversion to image the 3D magnetic units. The resultant distribution of effective susceptibility not only correlates well with the locations of Cenozoic igneous rocks known previously through drilling and seismic imaging, but also identifies the larger scale distribution of Mesozoic igneous rocks at greater depth in the west of the basin. The integrated interpretation results dominantly based on magnetic data shows that the above strategy is effective for identification of igneous rocks deep buried in the superimposed basin. Keywords: Identification of igneous rocks; Superimposed basin; Magnetic data

  1. Mechanisms Of Saucer-Shaped Sill Emplacement: Insight From Experimental Modeling

    Science.gov (United States)

    Galland, O.; Planke, S.; Malthe-Sørenssen, A.; Polteau, S.; Svensen, H.; Podladchikov, Y. Y.

    2006-12-01

    It has been recently demonstrated that magma intrusions in sedimentary basins had a strong impact on petroleum systems. Most of these intrusions are sills, and especially saucer-shaped sills. These features can be observed in many sedimentary basins (i.e. the Karoo basin, South Africa; the Norwegian and North Sea; the Tunguska basin, Siberia; the Neuquén basin in Argentina). The occurrence of such features in so various settings suggests that their emplacement results from fundamental processes. However, the mechanisms that govern their formation remain poorly constrained. Experiments were conducted to simulate the emplacement of saucer-shaped magma intrusions in sedimentary basins. The model rock and magma were fine-grained silica flour and molten vegetable oil, respectively. This modeling technique allows simultaneous simulation of magma emplacement and brittle deformation at a basin scale. For our purpose, we performed our experiments without external deformation. During the experiments, the oil was injected horizontally at constant flow rate within the silica flour. Then the oil initially emplaced in a sill, whereas the surface of the model inflated into a smooth dome. Subsequently, the oil propagated upwards along inclined sheets, finally reaching the surface at the edge of the dome. The resulting geometries of the intrusions were saucer-shaped sills. Then the oil solidified, and the model was cut in serial cross-sections through which the structures of the intrusive body and of the overburden can be observed. In order to constraint the processes governing the emplacement of such features, we performed a parametric study based on a set of experiments in which we systematically varied parameters such as the depth of emplacement and the injection flow rate of the oil. Our results showed that saucer diameters are larger at deeper level of emplacement. Opposite trend was obtained with varying injection flow rates. Based on our results, we conducted a detailed

  2. Emplacement of small and large buffer blocks

    International Nuclear Information System (INIS)

    Saari, H.; Nikula, M.; Suikki, M.

    2010-05-01

    The report describes emplacement of a buffer structure encircling a spent fuel canister to be deposited in a vertical hole. The report deals with installability of various size blocks and with an emplacement gear, as well as evaluates the achieved quality of emplacement and the time needed for installing the buffer. Two block assembly of unequal size were chosen for examination. A first option involved small blocks, the use of which resulted in a buffer structure consisting of small sector blocks 200 mm in height. A second option involved large blocks, resulting in a buffer structure which consists of eight blocks. In these tests, the material chosen for both block options was concrete instead of bentonite. The emplacement test was a three-phase process. A first phase included stacking a two meter high buffer structure with small blocks for ensuring the operation of test equipment and blocks. A second phase included installing buffer structures with both block options to a height matching that of a canister-encircling cylindrical component. A third phase included testing also the installability of blocks to be placed above the canister by using small blocks. In emplacement tests, special attention was paid to the installability of blocks as well as to the time required for emplacement. Lifters for both blocks worked well. Due to the mass to be lifted, the lifter for large blocks had a more heavy-duty frame structure (and other lifting gear). The employed lifters were suspended in the tests on a single steel wire rope. Stacking was managed with both block sizes at adequate precision and stacked-up towers were steady. The stacking of large blocks was considerably faster. Therefore it is probably that the overall handling of the large blocks will be more convenient at a final disposal site. From the standpoint of reliability in lifting, the small blocks were safer to install above the canister. In large blocks, there are strict shape-related requirements which are

  3. Radiometric, magnetic, and gravity study of the Quixadá batholith, central Ceará domain (NE Brazil): evidence for Pan-African/Brasiliano extension-controlled emplacement

    Science.gov (United States)

    Lopes de Castro, David; Mariano Gomes Castelo Branco, Raimundo; Martins, Guttenberg; Araújo de Castro, Neivaldo

    2002-10-01

    A geophysical survey was conducted in the central Ceará domain of the Borborema Province (NE Brazil). The aim of this investigation was to find geophysical evidence for the emplacement of the Quixadá batholith, which is a granitic body probably situated in the local extensional site in the oblique collisional regime of the Pan-African/Brasiliano collage. Remote sensing and airborne geophysical data provided information on the regional deformation that affected the intrusion and surrounding country rocks. In addition, a gravity study was used to determine the three-dimensional geometry and constrain the emplacement model of the Quixadá granite at depth. The trajectories of structural and magnetic lineaments suggest that the regional deformation is strongly influenced by dextral transcurrent movements of the major shear zones. The batholith, which shows an unusual positive gravity anomaly and a low U counts, displays a subhorizontal floor with several gently dipping areas, which are interpreted as magma feeder channels. The 2300 m thick root zones are roughly aligned with NE-SW-trending shear zones. Finally, the internal architecture of the pluton suggests that the Quixadá batholith was emplaced in a dilational shear zone tip area at the north end of Quixeramobim shear zone.

  4. Biological energy from the igneous rock enhances cell growth and enzyme activity

    International Nuclear Information System (INIS)

    Lin Y.-L.; Kuo, H.-S; Chen, C.-T.; Kuo, S.-C.

    2000-01-01

    Some effects from natural resources might be ignored and unused by humans. Environmental hormesis could be a phenomena necessary to bio-organism existence on earth. Since 1919, radiation and some heavy metal hormesis from the environment were proved in various reports. In this study, igneous rock with very low radioactivity and high ferrous activity was measured by multichannel analyzer and inductively coupled plasma analyzer. The water treated by igneous rock, both directly soaked or indirectly in contact, induced increased activities of glucose oxidase, catalase, peroxidase, and superoxide dismutase. It also increased cell growth of SC-M1, HCT-15, Raji, and fibroblast cell lines. The water after treatment of igneous rock had no change in pH values, but displayed decreased conductivity values. We assume that the igneous rock could transfer energy to water to change the molecular structure or conformation of water cluster, or by radiation hormesis effect could then induce increased enzyme activity and cell growth. It is also possible that the energy from rock may combine radiation hormesis with other transferable biological energy forms to change water cluster conformation

  5. Influence of crystallised igneous intrusions on fault nucleation and reactivation during continental extension

    Science.gov (United States)

    Magee, Craig; McDermott, Kenneth G.; Stevenson, Carl T. E.; Jackson, Christopher A.-L.

    2014-05-01

    Continental rifting is commonly accommodated by the nucleation of normal faults, slip on pre-existing fault surfaces and/or magmatic intrusion. Because crystallised igneous intrusions are pervasive in many rift basins and are commonly more competent (i.e. higher shear strengths and Young's moduli) than the host rock, it is theoretically plausible that they locally intersect and modify the mechanical properties of pre-existing normal faults. We illustrate the influence that crystallised igneous intrusions may have on fault reactivation using a conceptual model and observations from field and subsurface datasets. Our results show that igneous rocks may initially resist failure, and promote the preferential reactivation of favourably-oriented, pre-existing faults that are not spatially-associated with solidified intrusions. Fault segments situated along strike from laterally restricted fault-intrusion intersections may similarly be reactivated. This spatial and temporal control on strain distribution may generate: (1) supra-intrusion folds in the hanging wall; (2) new dip-slip faults adjacent to the igneous body; or (3) sub-vertical, oblique-slip faults oriented parallel to the extension direction. Importantly, stress accumulation within igneous intrusions may eventually initiate failure and further localise strain. The results of our study have important implications for the structural of sedimentary basins and the subsurface migration of hydrocarbons and mineral-bearing fluids.

  6. The new petrographic data about the Maymecha-Kotuy area of the Siberian flood-basalt province

    Science.gov (United States)

    Latyshev, Anton; Veselovskiy, Roman

    2010-05-01

    The Maymecha-Kotuy area of the Siberian flood-basalt province is of great interest because of its exceptional composition of igneous rocks. Alkaline-ultramafic rocks prevail there over basalts. It seems to be the only such trap province in the world. Investigation of the magma evolution and revealing of sources of magma is the task of an immense importance. Now there is a discussion about possible connections between the mass extinction on the boundary between Paleozoic and Mesozoic and magmatic activity expressed in formation of the largest Siberian flood-basalt province. Absence of the precise correlation of Maymecha-Kotuy area with other areas of the Siberian province does not allow estimating duration and volumes of the eruption of traps. Another question is if eruption of traps was uninterrupted or it had several pulses of magmatic activity. The solution of this problem will let estimate the degree of possible influence of the flood-basalt eruption to the environment. The represented results of investigations comprise all five igneous suites of Maymecha-Kotuy area. Petrographic investigation included research of thin sections and microprobe analyzes. The most entire sequences of Arydzhangsky and Kogotoksky suites and partly sequences of Pravoboyarsky, Delkansky and Maymechinsky suites were studied. This research allowed to reveal that the section of "Truba" on the Kotuy River belongs to Onkuchaksky suite (former lower Kogotoksky subsuite) and to reconsider the petrography of Arydzhangsky suite. Also, the research of geochemistry based on data of Fedorenko et al. (1997, 2000) lets suggest the sources of magma and its evolution. According to the new paleomagnetic data (Pavlov, Veselovskiy, Fetisova, EGU-2010), the new scheme of correlation of Maymecha-Kotuy trap section with Norilsk trap section was worked out and it became possible to estimate character of the magmatic activity in this region. In addition, it makes the contribution into the working out the

  7. Automated emplacement and retrieval of hazardous waste

    International Nuclear Information System (INIS)

    Slocum, A.H.; Hou, W.M.

    1987-01-01

    The design of several dedicated machines to perform simple tasks often results in higher system reliability and efficiency than the design of a single, multifunctional machine. Similarly, a reliable system for emplacement and retrieval of nuclear waste can be realized if emplacement/retrieval operations are decomposed into a well-defined series of independent tasks. The basic methodology is to design a system that eliminates contact between the waste package and the vehicle in the event of machine failure. The disabled vehicle can then be withdrawn to a safe location, repaired, and set back to resume normal operation

  8. Deciphering igneous and metamorphic events in high-grade rocks of the Wilmington complex, Delaware: Morphology, cathodoluminescence and backscattered electron zoning, and SHRIMP U-Pb geochronology of zircon and monazite

    Science.gov (United States)

    Aleinikoff, J.N.; Schenck, W.S.; Plank, M.O.; Srogi, L.A.; Fanning, C.M.; Kamo, S.L.; Bosbyshell, H.

    2006-01-01

    High-grade rocks of the Wilmington Complex, northern Delaware and adjacent Maryland and Pennsylvania, contain morphologically complex zircons that formed through both igneous and metamorphic processes during the development of an island-arc complex and suturing of the arc to Laurentia. The arc complex has been divided into several members, the protoliths of which include both intrusive and extrusive rocks. Metasedimentary rocks are interlayered with the complex and are believed to be the infrastructure upon which the arc was built. In the Wilmingto n Complex rocks, both igneous and metamorphic zircons occur as elongate and equant forms. Chemical zoning, shown by cathodoluminescence (CL), includes both concentric, oscillatory patterns, indicative of igneous origin, and patchwork and sector patterns, suggestive of metamorphic growth. Metamorphic monazites are chemically homogeneous, or show oscillatory or spotted chemical zoning in backscattered electron images. U-Pb geochronology by sensitive high resolution ion microprobe (SHRIMP) was used to date complexly zoned zircon and monazite. All but one member of the Wilmington Complex crystallized in the Ordovician between ca. 475 and 485 Ma; these rocks were intruded by a suite of gabbro-to-granite plutonic rocks at 434 ?? Ma. Detrital zircons in metavolcanic and metasedimentary units were derived predominantly from 0.9 to 1.4 Ga (Grenvillian) basement, presumably of Laurentian origin. Amphibolite to granulite facies metamorphism of the Wilmington Complex, recorded by ages of metamorphic zircon (428 ?? 4 and 432 ?? 6 Ma) and monazite (429 ?? 2 and 426 ?? 3 Ma), occurred contemporaneously with emplacement of the younger plutonic rocks. On the basis of varying CL zoning patterns and external morphologies, metamorphic zircons formed by different processes (presumably controlled by rock chemistry) at slightly different times and temperatures during prograde metamorphism. In addition, at least three other thermal episodes are

  9. Formation of D- and I-shaped geochemical profiles in saucer-shaped sills due to post- emplacement magma flow induced by thermal stresses

    Science.gov (United States)

    Aarnes, I.; Podladchikov, Y. Y.; Neumann, E.

    2007-12-01

    There are still unresolved problems in the processes of emplacement and crystallization of saucer shaped sill intrusions. We use geochemistry and numerical modelling in order to constrain identify processes in mafic sill intrusions. Profiles sampled through through a saucer-shaped sill complex in the Karoo igneous province, South Africa show a variety of geochemical variations. Some variations are observed repeatedly, i.e. the D- and I-shaped profiles. D-shaped profiles are recognized by having the least evolved composition in the center (high Mg#) with more evolved composition at the upper and lower margins (low Mg#), resulting in a D-shaped Mg# profile. I- shaped profiles are recognized by having no variation in the Mg# through the profile. The formation mechanism of D-shaped profiles is enigmatic, as classical fractional crystallization theory predicts C-shapes to occur. The least evolved composition will be at the margins where crystallization initiates, and with continued cooling and crystallization the center will be progressively more evolved. Hence, we need another formation mechanism. The most common explanation for D-shaped profiles is a movement of early formed phenocrysts towards the center due to flow segregation. However, petrographical evidences from a D-shaped profile in this study show no phenocryst assemblage in the center, and the modal composition is homogeneous through the profile. We propose that differentiation is caused by a melt flow from the central parts of the sill towards the margins driven by underpressure anomalies at the margins. The underpressures develop because of strong cooling gradients at the margins, assuming no volume change due to a rigid crystal network. The less compatible elements associated with the melt phase will be transported into the margins by advection, resulting in a more evolved total system composition from a higher total melt percentage. The central parts will progressively be depleted in the less compatible

  10. Potential Future Igneous Activity at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Cline, M.; Perry, F.; Valentine, G.; Smistad, E.

    2005-01-01

    Location, timing, and volumes of post-Miocene volcanic activity, along with expert judgment, provide the basis for assessing the probability of future volcanism intersecting a proposed repository for nuclear waste at Yucca Mountain, Nevada. Analog studies of eruptive centers in the region that may represent the style and extent of possible future igneous activity at Yucca Mountain have aided in defining the consequence scenarios for intrusion into and eruption through a proposed repository. Modeling of magmatic processes related to magma/proposed repository interactions has been used to assess the potential consequences of a future igneous event through a proposed repository at Yucca Mountain. Results of work to date indicate future igneous activity in the Yucca Mountain region has a very low probability of intersecting the proposed repository. Probability of a future event intersecting a proposed repository at Yucca Mountain is approximately 1.7 x 10 -8 per year. Since completion of the Probabilistic Volcanic Hazard Assessment (PVHA) in 1996, anomalies representing potential buried volcanic centers have been identified from aeromagnetic surveys. A re-assessment of the hazard is currently underway to evaluate the probability of intersection in light of new information and to estimate the probability of one or more volcanic conduits located in the proposed repository along a dike that intersects the proposed repository. US Nuclear Regulatory Commission regulations for siting and licensing a proposed repository require that the consequences of a disruptive event (igneous event) with annual probability greater than 1 x 10 -8 be evaluated. Two consequence scenarios are considered: (1) igneous intrusion-poundwater transport case and (2) volcanic eruptive case. These scenarios equate to a dike or dike swarm intersecting repository drifts containing waste packages, formation of a conduit leading to a volcanic eruption through the repository that carries the contents of

  11. Rooted in two Countries? Migrant Heritage, emplacement and the ‘Canon van Nederland’.

    NARCIS (Netherlands)

    van Faassen, M.; Hoekstra, F.G.

    2017-01-01

    Rooted in two Countries? Migrant Heritage, emplacement and the ‘Canon van Nederland’. In the cultural heritage sector theorizing emplacement is considered to be vital for identity: “people need to anchor there identity concretely to a location (emplacement)” (Grever&Van Boxtel, 2014). The question

  12. Results of Paleomagnetic Investigation of Angara - Taseeva Depression and Central Part of Tunguska Syncline (Siberian Trap Province, Russia)

    Science.gov (United States)

    Latyshev, A.; Veselovskiy, R. V.; Pavlov, V.

    2014-12-01

    Results of paleomagnetic investigation of two regions of Siberian Trap province (Angara - Taseeva depression and central part of Tunguska syncline) are performed here. Our work was dedicated to the estimation of dynamics and duration of magmatic activity during Siberian Traps emplacement. The conclusions are based on paleomagnetic study of large dolerite sills in the periphery of Siberian Trap province, tuffaceous deposits, small intrusions and lava flows of Tunguska syncline, and on geochronological data (Ivanov et al., 2013; Reichow et al., 2009). The presented data show that formation of Siberian Traps in these regions took place as several short bursts of magmatic activity led to large sill intrusions and eruptions of tuffs. This data are in agreement with the pulsating character of magmatic activity in the Northern part of Siberian platform (Pavlov et al., 2014). The most powerful burst of magmatic activity in Angara-Taseeva syncline is supposed to be synchronous to the main phase of volcanic eruptions in the Northern part of Siberian platform and emplacement of ore-bearing intrusions in Noril'sk district. This study was funded by grant RFBR # 14-05-31447.

  13. Review of potential host rocks for radioactive waste disposal in the Piedmont Province of South Carolina

    International Nuclear Information System (INIS)

    Secor, D.T. Jr.

    1980-10-01

    This report reviews the geology of the Piedmont Province of South Carolina with the aim of designating rock units favorable for field exploration for a potential underground repository for the storage of radioactive waste. Most of the rocks in the South Carolina Piedmont are metamorphosed sedimentary volcanic or igneous rocks that have experienced at least one episode of strong deformation. As a consequence of this deformation, they have irregular shapes, making it difficult to predict their subsurface extent. In evaluating the suitability of the rock units for radioactive waste storage, certain criteria were found to be particularly useful. The requirements that the storage site be located in a large volume of homogeneous, impermeable, relatively unfractured rock was the most important criteria in eliminating most of the Piedmont rock units for consideration as field study areas. Six large late- to post-tectonic igneous plutons (Winnsboro, Liberty Hill, Ogden, Newberry, Lowrys, and Bald Rock) are recommended as field study areas

  14. On the source material of magmas - with special reference to Nd isotopic ratios of igneous rocks

    International Nuclear Information System (INIS)

    Shuto, Kenji

    1980-01-01

    In 1973, the Sm-Nd method was first used for the measurement of the absolute age of igneous rocks and meteorites. Subsequently in the following years, the research works by means of the Nd isotopic ratio in igneous rocks have been made strenuously in order to reveal the chemistry of the source materials of magma giving rise to the igneous rocks and further the evolution process of mantle and earth's crust. The fundamental items for the Sm-Nd method are explained. Then, the research results more important in the above connection are given. Finally, the ideas by the author concerning the source materials of magma are presented from the data available on the Nd isotopes in meteorites and igneous rocks. The following matters are described: the fundamentals of Sm-Nd method, the Nd content in seawater, the negative correlation between Nd and Sr isotopic ratios in igneous rocks, magma source materials and Nd isotopes, and considerations on magma source materials. (J.P.N.)

  15. Magnetostratigraphy of the Naude's Nek Section (Karoo Traps): News Constraints on the Eruptive Sequence

    Science.gov (United States)

    Moulin, M.; Jay, A. E.; Fluteau, F.; Marsh, J. S.; Courtillot, V.; Gerard, M.; Quidelleur, X.

    2008-12-01

    A causal relationship between large igneous provinces (LIP) and mass extinctions (ME) or oceanic anoxia events (OAE) is supported by an increasing data base of age determinations. Although the impact of recent (much smaller) volcanic eruptions on climate is understood as being largely due to injection of SO2 into the stratosphere, the environmental effects of LIP eruptions remain ill understood. Successful climate modelling requires high-resolution timing of volcanism, i.e. number, volume and duration of peak episodes. Chenet et al (2008, and in revision) have studied the Deccan traps, which correlate with the major KT crisis, combining geochronology (K-Ar), paleomagnetism (secular variation), volcanology (flow types) and analysis of alteration levels between flows (red boles); they have shown that emplacement occurred as a small number of discrete, very large and short-lived pulses (see Courtillot et al, same session). But mass extinctions are not all alike, in pattern or intensity. Some large igneous provinces are correlated with only minor crises, e.g. the Karoo traps formed near the Pliensbachian-Toarcian boundary (~180 Ma). Remnants of these traps outcrop over >2.5×106 km2. Jourdan et al. (2008) find that the Karoo traps were emplaced over some 4 Myr, significantly longer than the Deccan. However, the Karoo province does seem to comprise brief (traps), located in South Africa near the southern border of Lesotho. Our first determinations (40K-40Ar Cassignol-Gillot technique) yield ages of 180±1.8 Ma, in good agreement with previous studies. Detailed flow by flow magnetostratigraphy (site-mean directions based on thermal demagnetization) shows that the eruptive sequence can be divided into several volcanic pulses having likely lasted less than ~100 years. We have obtained a particularly detailed record of the only reversal found in the sequence and identified by van Zijl 50 years ago: 136 m of lava erupted over less than a few thousand years. Although our

  16. Cryovolcanic Emplacement of Domes on Europa

    Science.gov (United States)

    Quick, Lynnae C.; Glaze, Lori S.; Baloga, Stephen M.

    2016-01-01

    Here we explore the hypothesis that certain domes on Europa may have been produced by the extrusion of viscous cryolavas. A new mathematical method for the emplacement and relaxation of viscous lava domes is presented and applied to putative cryovolcanic domes on Europa. A similarity solution approach is applied to the governing equation for fluid flow in a cylindrical geometry, and dome relaxation is explored assuming a volume of cryolava has been rapidly emplaced onto the surface. Nonphysical sin- gularities inherent in previous models for dome relaxation have been eliminated, and cryolava cooling is represented by a time-variable viscosity. We find that at the onset of relaxation, bulk kinematic viscosities may lie in the range between 10(exp 3) and 10(exp 6) sq m/s, while the actual fluid lava viscosity may be much lower. Plausible relaxation times to form the domes, which are linked to bulk cryolava rheology, are found to range from 3.6 days to 7.5 years. We find that cooling of the cryolava, while dominated by conduction through an icy skin, should not prevent fluids from advancing and relaxing to form domes within the timescales considered. Determining the range of emplacement conditions for putative cryolava domes will shed light on Europa's resurfacing history. In addition, the rheologies and compositions of erupted cryolavas have implications for subsurface cryomagma ascent and local surface stress conditions on Europa.

  17. The ammonium content in the Malayer igneous and metamorphic rocks (Sanandaj-Sirjan Zone, Western Iran)

    Science.gov (United States)

    Ahadnejad, Vahid; Hirt, Ann Marie; Valizadeh, Mohammad-Vali; Bokani, Saeed Jabbari

    2011-04-01

    The ammonium (NH4+) contents of the Malayer area (Western Iran) have been determined by using the colorimetric method on 26 samples from igneous and metamorphic rocks. This is the first analysis of the ammonium contents of Iranian metamorphic and igneous rocks. The average ammonium content of metamorphic rocks decreases from low-grade to high-grade metamorphic rocks (in ppm): slate 580, phyllite 515, andalusite schist 242. In the case of igneous rocks, it decreases from felsic to mafic igneous types (in ppm): granites 39, monzonite 20, diorite 17, gabbro 10. Altered granitic rocks show enrichment in NH4+ (mean 61 ppm). The high concentration of ammonium in Malayer granites may indicate metasedimentary rocks as protoliths rather than meta-igneous rocks. These granitic rocks (S-types) have high K-bearing rock-forming minerals such as biotite, muscovite and K-feldspar which their potassium could substitute with ammonium. In addition, the high ammonium content of metasediments is probably due to inheritance of nitrogen from organic matter in the original sediments. The hydrothermally altered samples of granitic rocks show highly enrichment of ammonium suggesting external sources which intruded additional content by either interaction with metasedimentary country rocks or meteoritic solutions.

  18. EMPLACEMENT GANTRY ITS STANDARDS IDENTIFICATION STUDY

    International Nuclear Information System (INIS)

    Voegele, M.

    2005-01-01

    To date, the project has established ITS performance requirements for SSCs based on identification and categorization of event sequences that may result in a radiological release. These performance requirements are defined within the NSDB. Further, SSCs credited with performing safe functions are classified as ITS. In turn, perform confirmation for these SSCs is sought through the use of consensus code and standards. The purpose of this study is to identify applicable codes and standards for the WP Emplacement Gantry ITS SSCs. Further, this study will form the basis for selection and the extent of applicability of each code and standard. This study is based on the design development completed for LA only. Accordingly, identification of ITS SSCs beyond those defined within the NSDB are based on designs that may be subject to further development during detail design. Furthermore, several design alternatives may still be under consideration to satisfy certain safety functions, and that final selection will not be determined until further design development has occurred. Therefore, for completeness, throughout this study alternative designs currently under considered will be discussed. Further, the results of this study will be subject to evaluation as part of a follow-on GAP analysis study. Based on the results of this study the GAP analysis will evaluate each code and standard to ensure each ITS performance requirement is fully satisfied. When a performance requirement is not fully satisfied a ''gap'' is highlighted. Thereafter, the study will identify supplemental requirements to augment the code or standard to meet performance requirements. Further, the GAP analysis will identify non-standard areas of the design that will be subject to a Development Plan. Non-standard components and non-standard design configurations are defined as areas of the design that do not follow standard industry practices or codes and standards. Whereby, performance confirmation cannot be

  19. Origins of igneous microgranular enclaves in granites: the example of Central Victoria, Australia

    Science.gov (United States)

    Clemens, J. D.; Elburg, M. A.; Harris, C.

    2017-10-01

    To investigate their genesis and relations with their host rocks, we study igneous microgranular enclaves (IMEs) in the c. 370 Ma, post-orogenic, high-level, felsic plutons and volcanic rocks of Central Victoria, Australia. The IMEs are thermally quenched magma globules but are not autoliths, and they do not form mixing series with their host magmas. These IMEs generally represent hybrids between mantle-derived magmas and very high- T crust-derived melts, modified by fractionation, ingestion of host-derived crystals and, to a lesser extent, by chemical interactions with their hosts. Isotopic and elemental evidence suggests that their likely mafic progenitors formed by partial melting of subcontinental mantle, but that the IME suites from different felsic host bodies did not share a common initial composition. We infer that melts of heterogeneous mantle underwent high- T hybridisation with melts from a variety of crustal rocks, which led to a high degree of primary variability in the IME magmas. Our model for the formation of the Central Victorian IMEs is likely to be applicable to other occurrences, especially in suites of postorogenic granitic magmas emplaced in the shallow crust. However, there are many different origins for the mingled magma globules that we call IMEs, and different phenomena seem to occur in differing tectonic settings. The complexity of IME formation means that it is difficult to unravel the petrogenesis of these products of chaotic magma processes. Nevertheless, the survival of fine-grained, non-equilibrium mineralogy and texture in the IMEs suggests that their tenure in the host magmas must have been geologically brief.

  20. TBV 361 RESOLUTION ANALYSIS: EMPLACEMENT DRIFT ORIENTATION

    International Nuclear Information System (INIS)

    Lin, M.; Kicker, D.C.; Sellers, M.D.

    1999-01-01

    The purpose of this To Be Verified/To Be Determined (TBX) resolution analysis is to release ''To Be Verified'' (TBV)-361 related to the emplacement drift orientation. The system design criterion in ''Subsurface Facility System Description Document'' (CRWMS M andO 1998a, p.9) specifies that the emplacement drift orientation relative to the dominant joint orientations should be at least 30 degrees. The specific objectives for this analysis include the following: (1) Collect and evaluate key block data developed for the repository host horizon rock mass. (2) Assess the dominant joint orientations based on available fracture data. (3) Document the maximum block size as a function of drift orientation. (4) Assess the applicability of the drift orientation/joint orientation offset criterion in the ''Subsurface Facility System Description Document'' (CRWMS M andO 1998a, p.9). (5) Consider the effects of seepage on drift orientation. (6) Verify that the viability assessment (VA) drift orientation complies with the drift orientation/joint orientation offset criterion, or provide justifications and make recommendations for modifying the VA emplacement drift layout. In addition to providing direct support to the System Description Document (SDD), the release of TBV-361 will provide support to the Repository Subsurface Design Department. The results from this activity may also provide data and information needs to support the MGR Requirements Department, the MGR Safety Assurance Department, and the Performance Assessment Organization

  1. Longevity of Emplacement Drift Ground Support Materials

    International Nuclear Information System (INIS)

    Tang, D.

    2000-01-01

    The purpose of this analysis is to evaluate the factors affecting the longevity of emplacement drift ground support materials and to develop a basis for selection of materials for ground support that will function throughout the preclosure period. The Development Plan (DP) for this analysis is given in CRWMS M and O (Civilian Radioactive Waste Management System Management and Operating Contractor) (1999a). The candidate materials for ground support are steel (carbon steel, ductile cast iron, galvanized steel, and stainless steel, etc.) and cement. Steel will mainly be used for steel sets, lagging, channels, rock bolts, and wire mesh. Cement usage is only considered in the case of grouted rock bolts. The candidate materials for the invert structure are steel and crushed rock ballast. The materials shall be evaluated for the repository emplacement drift environment under a specific thermal loading condition based on the proposed License Application Design Selection (LADS) design. The analysis consists of the following tasks: (1) Identify factors affecting the longevity of ground control materials for use in emplacement drifts. (2) Review existing documents concerning behavior of candidate ground control materials during the preclosure period. The major criteria to be considered for steel are mechanical and thermal properties, and durability, of which corrosion is the most important concern. (3) Evaluate the available results and develop recommendations for material(s) to be used

  2. Sm-Nd study of Precambrian crustal development in the Prieska-Copperton region, Cape Province

    International Nuclear Information System (INIS)

    Cornell, D.H.; Hawkesworth, C.J.; Van Calsteren, P.; Scott, W.D.

    1986-01-01

    Samples representing the major lithological units between Copperton and Prieskapoort in the Cape Province have been analysed for Sm and Nd concentrations and Nd isotopic compositions. The ∼ 3000 Ma Marydale Group is shown to extend without major chronostratigraphic breaks from slightly metamorphosed basalt and arkose west of the Doornberg Fault at Prieskapoort to highly metamorphosed gneisses east of the Brakbos Fault at Copperton. Evidence is found of plutonic alkaline igneous activity, and possibly volcanism, which occurred during the ∼ 1 900 Ma Kheis tectogenesis. Early Proterozoic material apparently dominates the lower crustal region of the eastern Namaqua Province sampled by kimberlites. Sm-Nd data for the Copperton Formation of the Namaqua Province places an upper limit of ∼ 1 514 Ma and lower limit of ∼ 1 350 Ma on its origin. Omission of basaltic samples from the isochron regression yields the younger age, which is more easily reconciled with Pb isotope data. Volcanism is envisaged from a mantle source with a history of light rare-earth depletion relative to the chondritic earth model. By analogy with modern tectonic environments, the Copperton Formation probably formed in an active continental margin or island arc environment

  3. Solar energy emplacement developer

    Science.gov (United States)

    Mortensen, Michael; Sauls, Bob

    1991-01-01

    A preliminary design was developed for a Lunar Power System (LPS) composed of photovoltaic arrays and microwave reflectors fabricated from lunar materials. The LPS will collect solar energy on the surface of the Moon, transform it into microwave energy, and beam it back to Earth where it will be converted into usable energy. The Solar Energy Emplacement Developer (SEED) proposed will use a similar sort of solar energy collection and dispersement to power the systems that will construct the LPS.

  4. The Alto Paraguay Alkaline Province: petrographic, geochemical and geochronological characteristics; Provincia alcalina Alto Paraguai: caracteristicas petrograficas, geoquimicas e geocronologicas

    Energy Technology Data Exchange (ETDEWEB)

    Velazquez Fernandez, Victor

    1996-12-31

    The Alto Paraguay Province is located at the border of the State of Mato Grosso do Sul and Paraguay, between the coordinates 21 deg 10{sup `}to 23 deg 25{sup `}of Southern latitude and 57 deg 10{sup `} to 58 deg 00{sup `}, having the city of Porto Murtinho as the main reference point. The geotectonic domain of the area is governed by the precambric units of the Southern extreme of the Amazonic craton which developed a long and accentuated activity, giving rise to folds and important faults, that in several cases seem to have exerted an effective control of the magmatic manifestations. Radiometric data indicate that the emplacement of the syenitic bodies took place in the Permo-Triassic period, with a major incidence in the interval 260-240 Ma, representing thus, an important phase of alkaline magmatic affinity associated to the Parana Basin which is believed is to be unique, since the other known areas (Central, Amambay and Rio Apa Provinces, Paraguay, Velasco Province, Bolivia) are considerably younger (140-120 Ma). Syenitic rocks from the Alto Paraguay Province show wide variation in the ratio {sup 87} Sr/{sup 86} Sr (0.703361 - 0.707734). Excluding the Cerro Boggiani rocks (0.703837-0.707734), values for the nepheline syenites (0.703361-0.703672) general lower than those of the other syenites types. Alkaline syenites cover the interval 0.703510- 0.703872, while quartz syenites and syenogranites are 0.704562 and 0.707076, respectively. geologic evidence, in addition to petrographic, geochemical and isotopic (Sr) data, suggest that the syenitic rocks have been derived from an unique mantelic parental liquid, by fractional crystallization and assimilation processes, which are assumed to be occurred during the emplacement of the magma in the crust. (author) 124 refs., 52 figs., 7 tabs.

  5. The Alto Paraguay Alkaline Province: petrographic, geochemical and geochronological characteristics; Provincia alcalina Alto Paraguai: caracteristicas petrograficas, geoquimicas e geocronologicas

    Energy Technology Data Exchange (ETDEWEB)

    Velazquez Fernandez, Victor

    1997-12-31

    The Alto Paraguay Province is located at the border of the State of Mato Grosso do Sul and Paraguay, between the coordinates 21 deg 10{sup `}to 23 deg 25{sup `}of Southern latitude and 57 deg 10{sup `} to 58 deg 00{sup `}, having the city of Porto Murtinho as the main reference point. The geotectonic domain of the area is governed by the precambric units of the Southern extreme of the Amazonic craton which developed a long and accentuated activity, giving rise to folds and important faults, that in several cases seem to have exerted an effective control of the magmatic manifestations. Radiometric data indicate that the emplacement of the syenitic bodies took place in the Permo-Triassic period, with a major incidence in the interval 260-240 Ma, representing thus, an important phase of alkaline magmatic affinity associated to the Parana Basin which is believed is to be unique, since the other known areas (Central, Amambay and Rio Apa Provinces, Paraguay, Velasco Province, Bolivia) are considerably younger (140-120 Ma). Syenitic rocks from the Alto Paraguay Province show wide variation in the ratio {sup 87} Sr/{sup 86} Sr (0.703361 - 0.707734). Excluding the Cerro Boggiani rocks (0.703837-0.707734), values for the nepheline syenites (0.703361-0.703672) general lower than those of the other syenites types. Alkaline syenites cover the interval 0.703510- 0.703872, while quartz syenites and syenogranites are 0.704562 and 0.707076, respectively. geologic evidence, in addition to petrographic, geochemical and isotopic (Sr) data, suggest that the syenitic rocks have been derived from an unique mantelic parental liquid, by fractional crystallization and assimilation processes, which are assumed to be occurred during the emplacement of the magma in the crust. (author) 124 refs., 52 figs., 7 tabs.

  6. Salt Repository Project waste emplacement mode decision paper: Revison 1

    International Nuclear Information System (INIS)

    1987-08-01

    This paper provides a recommendation as to the mode of waste emplacement to be used as the current basis for site characterization activity for the Deaf Smith County, Texas, high level nuclear waste repository site. It also presents a plan for implementing the recommendation so as to provide a high level of confidence in the project's success. Since evaluations of high-level waste disposal in geologic repositories began in the 1950s, most studies emplacement in salt formations employed the vertical orientation for emplacing waste packages in boreholes in the floor of the underground facility. This orientation was used in trials at Project Salt Vault in the 1960s. The Waste Isolation Pilot Plant (WIPP) has recently settled on a combination of vertical and horizontal modes for various waste types. This paper analyzes the information available and develops a project position upon which to base current site characterization activities. The position recommended is that the SRP should continue to use the vertical waste emplacement mode as the reference design and to carry the horizontal mode as a ''passive'' alternative. This position was developed based upon the conclusions of a decision analysis, risk assessment, and cost/schedule impact assessment. 52 refs., 6 figs., 1 tab

  7. The Paranagua Batholith: proposition, age, petrogenetic considerations and tectonics implication

    International Nuclear Information System (INIS)

    Basei, M.A.S.; Reis Neto, J.M. dos

    1990-01-01

    The Paranagua Batholith comprises the major portion of the Costeiro Domain which is one of the three internal tectonic unities of the Joinville Massif in the southern Brazil (Mantiqueira Province). U-Pb in zircon (614 ± 10 Ma) and Rb-Sr whole rock isochron (543 ± 21 Ma) data are interpreted respectively as ages of the mineral crystallization and granitoid emplacement for the main igneous phase of the Paranagua Batholith. Sr, Pb and Nd analyses carried on this coarse biotite-microcline granitoid reveals its crustal melt origin with a source in the lower crust. It is here proposed the association of this Costeiro Domain (Parana), the Costeiro Complex (Sao Paulo) and Brusque Belt (or Tijucas Belt, Santa Catarina) as parts of the same collisional structure of the southern region of South America. (author)

  8. Heat transfer effects in vertically emplaced high level nuclear waste container

    International Nuclear Information System (INIS)

    Moujaes, S.F.; Lei, Y.M.

    1994-01-01

    Modeling free convection heat transfer in a cylindrical annular enclosure is still an active area of research and an important problem to be addressed in the high level nuclear waste repository. For the vertically emplaced waste container, the air gap which is between the container shell and the rock borehole, have an important role of dissipating heat to surrounding rock. These waste containers are vertically emplaced in the borehole 300 meters just below ground, and in a horizontal grid of 30 x 8 meters apart. The borehole will be capped after the container emplacement. The expected initial heat generated is between 3-4.74 kW per container depending on the type of waste. The goal of this study is to use a computer simulation model to find the borehole wall, air-gap and the container outer wall temperature distributions. The borehole wall temperature history has been found in the previous study, and was estimated to reach a maximum temperature of about 218 degrees C after 18 years from the emplacement. The temperature history of the rock surface is then used for the air-gap simulation. The problem includes convection and radiation heat transfer in a vertical enclosure. This paper will present the results of the convection in the air-gap over one thousand years after the containers' emplacement. During this long simulation period it was also observed that a multi-cellular air flow pattern can be generated in the air gap

  9. Palaeomagnetism and K-Ar age of Mesozoic and Cenozoic igneous rocks from Antarctica

    International Nuclear Information System (INIS)

    Valencio, D.A.; Mendia, J.E.; Vilas, J.F.

    1979-01-01

    A new analysis of palaeomagnetic data for igneous rocks from Deception Island, 25 de Mayo Island (King George Island) and Cape Spring, are given. K-Ar age determinations indicate that most of the igneous samples from 25 de Mayo Island included in the palaeomagnetic study are of Late Mesozoic/Early Tertiary age. The significance of these palaeomagnetic-radiometric data on the hypothesis of oroclinal bending of the Antarctic Peninsula and on the apparent polar movement of Antarctica is discussed. The positions of palaeomagnetic poles for the Andean igneous complex indicate that there has not been any apparent post-Late Cretaceous/Early Tertiary oroclinal bending in the Antarctic Peninsula from 74 0 S to 62 0 S. A comparison of the positions of palaeomagnetic poles for Antarctica and Australia suggests that the direction of apparent polar movement relative to Antarctica reversed after the Miocene. (Auth.)

  10. Teaching Igneous and Metamorphic Petrology Through Guided Inquiry Projects

    Science.gov (United States)

    McMillan, N. J.

    2003-12-01

    Undergraduate Petrology at New Mexico State University (GEOL 399) has been taught using three, 5-6 week long projects in place of lectures, lab, and exams for the last six years. Reasons for changing from the traditional format include: 1) to move the focus from identification and memorization to petrologic thinking; 2) the need for undergraduate students to apply basic chemical, structural, and field concepts to igneous and metamorphic rocks; 3) student boredom in the traditional mode by the topic that has captivated my professional life, in spite of my best efforts to offer thrilling lectures, problems, and labs. The course has three guided inquiry projects: volcanic, plutonic, and pelitic dynamothermal. Two of the rock suites are investigated during field trips. Each project provides hand samples and thin sections; the igneous projects also include whole-rock major and trace element data. Students write a scientific paper that classifies and describes the rocks, describes the data (mineralogical and geochemical), and uses data to interpret parameters such as tectonic setting, igneous processes, relationship to phase diagrams, geologic history, metamorphic grade, metamorphic facies, and polymetamorphic history. Students use the text as a major resource for self-learning; mini-lectures on pertinent topics are presented when needed by the majority of students. Project scores include evaluation of small parts of the paper due each Friday and participation in peer review as well as the final report. I have found that petrology is much more fun, although more difficult, to teach using this method. It is challenging to be totally prepared for class because students are working at different speeds on different levels on different aspects of the project. Students enjoy the course, especially the opportunity to engage in scientific investigation and debate. A significant flaw in this course is that students see fewer rocks and have less experience in rock classification

  11. Permeability of granular beds emplaced in vertical drill holes

    International Nuclear Information System (INIS)

    Griffiths, S.K.; Morrison, F.A. Jr.

    1979-01-01

    To determine the permeabilities of granular materials emplaced in vertical drill holes used for underground nuclear tests, an experiment at the USDOE Nevada Test Site (NTS) was conducted. As the hole is being filled, falling material increases pressure above and within the granular beds beneath. When the filling operation starts or stops, a transient pressure response occurs within the beds; measurements of this response in beds of various compositions were made. The permeabilities after emplacement were found by matching analytical predictions of the response to these data. This information is useful in assuring the containment of nuclear tests conducted in such drill holes

  12. Conceptual designs of automated systems for underground emplacement and retrieval of nuclear waste

    International Nuclear Information System (INIS)

    Slocum, A.H.; Hou, W.M.; Park, K.; Hochmuth, C.; Thurston, D.C.

    1987-01-01

    Current designs of underground nuclear waste repositories have not adequately addressed the possibility of automated, unmanned emplacement and retrieval. This report will present design methodologies for development of an automated system for underground emplacement of nuclear waste. By scaling generic issues to different repositories, it is shown that a two vehicle automated waste emplacement/retrieval system can be designed to operate in a fail-safe mode. Evaluation of cost at this time is not possible. Significant gains in worker safety, however, can be realized by minimizing the possibility of human exposure

  13. Fracturing of doleritic intrusions and associated contact zones: Implications for fluid flow in volcanic basins

    Science.gov (United States)

    Senger, Kim; Buckley, Simon J.; Chevallier, Luc; Fagereng, Åke; Galland, Olivier; Kurz, Tobias H.; Ogata, Kei; Planke, Sverre; Tveranger, Jan

    2015-02-01

    Igneous intrusions act as both carriers and barriers to subsurface fluid flow and are therefore expected to significantly influence the distribution and migration of groundwater and hydrocarbons in volcanic basins. Given the low matrix permeability of igneous rocks, the effective permeability in- and around intrusions is intimately linked to the characteristics of their associated fracture networks. Natural fracturing is caused by numerous processes including magma cooling, thermal contraction, magma emplacement and mechanical disturbance of the host rock. Fracturing may be locally enhanced along intrusion-host rock interfaces, at dyke-sill junctions, or at the base of curving sills, thereby potentially enhancing permeability associated with these features. In order to improve our understanding of fractures associated with intrusive bodies emplaced in sedimentary host rocks, we have investigated a series of outcrops from the Karoo Basin of the Eastern Cape province of South Africa, where the siliciclastic Burgersdorp Formation has been intruded by various intrusions (thin dykes, mid-sized sheet intrusions and thick sills) belonging to the Karoo dolerite. We present a quantified analysis of fracturing in- and around these igneous intrusions based on five outcrops at three individual study sites, utilizing a combination of field data, high-resolution lidar virtual outcrop models and image processing. Our results show a significant difference between the three sites in terms of fracture orientation. The observed differences can be attributed to contrasting intrusion geometries, outcrop geometry (for lidar data) and tectonic setting. Two main fracture sets were identified in the dolerite at two of the sites, oriented parallel and perpendicular to the contact respectively. Fracture spacing was consistent between the three sites, and exhibits a higher degree of variation in the dolerites compared to the host rock. At one of the study sites, fracture frequency in the

  14. Paleozoic and Paleoproterozoic Zircon in Igneous Xenoliths Assimilated at Redoubt Volcano, Alaska

    Science.gov (United States)

    Bacon, C. R.; Vazquez, J. A.; Wooden, J. L.

    2010-12-01

    Historically active Redoubt Volcano is a basalt-to-dacite cone constructed upon the Jurassic-early Tertiary Alaska-Aleutian Range batholith. New SHRIMP-RG U-Pb age and trace-element concentration results for zircons from gabbroic xenoliths and crystal-rich andesitic mush from a late Pleistocene pyroclastic deposit indicate that ~310 Ma and ~1865 Ma igneous rocks underlie Redoubt at depth. Two gabbros have sharply terminated prismatic zircons that yield ages of ~310 Ma. Zircons from a crystal mush sample are overwhelmingly ~1865 Ma and appear rounded due to incomplete dissolution. Binary plots of element concentrations or ratios show clustering of data for ~310-Ma grains and markedly coherent trends for ~1865-Ma grains; e.g., ~310-Ma grains have higher Eu/Eu* than most of the ~1865-Ma grains, the majority of which form a narrow band of decreasing Eu/Eu* with increasing Hf content which suggests that ~1865-Ma zircons come from igneous source rocks. It is very unlikely that detrital zircons from a metasedimentary rock would have this level of homogeneity in age and composition. One gabbro contains abundant ~1865 Ma igneous zircons, ~300-310 Ma fluid-precipitated zircons characterized by very low U and Th concentrations and Th/U ratios, and uncommon ~100 Ma zircons. We propose that (1) ~310 Ma gabbro xenoliths from Redoubt Volcano belong to the same family of plutons dated by Aleinikoff et al. (USGS Circular 1016, 1988) and Gardner et al. (Geology, 1988) located ≥500 km to the northeast in basement rocks of the Wrangellia and Alexander terranes and (2) ~1865 Ma zircons are inherited from igneous rock, potentially from a continental fragment that possibly correlates with the Fort Simpson terrane or Great Bear magmatic zone of the Wopmay Orogen of northwestern Laurentia. Possibly, elements of these Paleoproterozoic terranes intersected the Paleozoic North American continental margin where they may have formed a component of the basement to the Wrangellia

  15. Heat production rate from radioactive elements in igneous and metamorphic rocks in Eastern Desert, Egypt

    International Nuclear Information System (INIS)

    Abbady, Adel G.E.; El-Arabi, A.M.; Abbady, A.

    2006-01-01

    Radioactive heat-production data of Igneous and Metamorphic outcrops in the Eastern Desert are presented. Samples were analysed using a low level gamma-ray spectrometer (HPGe) in the laboratory. A total of 205 rock samples were investigated, covering all major rock types of the area. The heat-production rate of igneous rocks ranges from 0.11 (basalt) to 9.53 μW m -3 (granite). In metamorphic rocks it varies from 0.28 (serpentinite ) to 0.91 μW m -3 (metagabbro). The contribution due to U is about 51%, as that from Th is 31% and 18% from K. The corresponding values in igneous rocks are 76%, 19% and 5%, respectively. The calculated values showed good agreement with global values except in some areas containing granites

  16. Heat production rate from radioactive elements in igneous and metamorphic rocks in eastern desert, Egypt

    International Nuclear Information System (INIS)

    Abbady, A G.E.; Arabi, A.M.; Abbay, A.

    2005-01-01

    Radioactive heat - production data of igneous and metamorphic rocks cropping out from the eastern desert are presented. Samples were analysed using low level gamma-ray spectrometer (HPGe) in the laboratory. A total of 205 rock samples were investigated, covering all major rock types of the area. The heat-production rate of igneous rocks ranges from 0.11 (basalt) to 9.53 Μ Wm-3 (granite). In metamorphic rocks it varies from 0.28 (serpentinite) to 0.91 (metagabroo) Μ W.m-3. The contribution due to U is about (51%), whereas that of Th (31%) and (18%) by K. The corresponding values in igneous rocks are 76%: 19%: 5%, respectively. The calculated values showed good agreement with global values expect in some areas contained granite rocks

  17. Parameters and criteria influencing the selection of waste emplacement configurations in mined geologic repositories

    International Nuclear Information System (INIS)

    Bechthold, W.; Closs, K.D.; Papp, R.

    1988-01-01

    Reference concepts for repositories in deep geological formations have been developed in several countries. For these concepts, emplacement configurations vary within a wide range that comprises drift emplacement of unshielded or self-shielded packages and horizontal or vertical borehole emplacement. This is caused by different parameters, criteria, and criteria weighting factors. Examples for parameters are the country's nuclear power program and waste management policy, its geological situation, and safety requirements, examples for criteria and repository area requirements, expenditures of mining and drilling, and efforts for emplacement and, if required, retrieval. Due to the variety of these factors and their ranking in different countries, requirements for a safe, dependable and cost-effective disposal of radioactive waste can be met in various ways

  18. The genesis of the newly discovered giant Wuben magmatic Fe-Ti oxide deposit in the Emeishan Large Igneous Province: a product of the late-stage redistribution and sorting of crystal slurries

    Science.gov (United States)

    Bai, Zhong-Jie; Zhong, Hong; Zhu, Wei-Guang; Hu, Wen-Jun; Chen, Cai-Jie

    2018-04-01

    A giant Fe-Ti oxide deposit hosted by the Wuben mafic intrusion has recently been discovered in the Pan-Xi area of the Emeishan Large Igneous Province (ELIP). The evolved compositions of the gangue minerals within the Fe-Ti oxide ores indicate that they formed during later stages of magma differentiation than those within the neighboring Panzhihua intrusion or other ore-bearing intrusions in this area. The rocks from the Wuben intrusion and MZb of the Panzhihua intrusion contain compositionally similar silicate minerals and have similar titanomagnetite/ilmenite ratios, suggesting that the former is related to and probably connected to the latter by subsurface magmatic conduits. This indicates that unconsolidated minerals that formed in the MZb flowed as crystal slurries into the Wuben magma chamber during the later stages of evolution of the parental magma. The later secondary enrichment of Fe-Ti oxides by mechanical redistribution and the sorting of crystals as a result of density and size differences generated the Wuben massive Fe-Ti oxide bodies. The ilmenite was commonly saturated in the magma at late stage of differentiation in the ELIP, thereby the associated deposit contains much higher contents of ilmenite. This indicates that future exploration for Fe-Ti oxide mineralization in the ELIP should not merely focus on the lower parts of large layered intrusions but should also include nearby relatively small intrusions or even the upper parts of large intrusions, especially as ilmenite-enriched Fe-Ti oxide deposits may have greater economic value than ilmenite-poor deposits.

  19. Macrocrystal phlogopite Rb-Sr dates for the Ekati property kimberlites, Slave Province, Canada: evidence for multiple intrusive episodes in the Paleocene and Eocene

    Science.gov (United States)

    Creaser, Robert A.; Grütter, Herman; Carlson, Jon; Crawford, Barbara

    2004-09-01

    New Rb-Sr age determinations using macrocrystal phlogopite are presented for 27 kimberlites from the Ekati property of the Lac de Gras region, Slave Province, Canada. These new data show that kimberlite magmatism at Ekati ranges in age from at least Late Paleocene (∼61 Ma) to Middle Eocene time (∼45 Ma). Older, perovskite-bearing kimberlites from Ekati extend this age range to Late Cretaceous time (∼74 Ma). Within this age range, emplacement episodes at ∼48, 51-53, 55-56 and 59-61 Ma can be recognized. Middle Eocene kimberlite magmatism of the previously dated Mark kimberlite (∼47.5 Ma) is shown to include four other pipes from the east-central Ekati property. A single kimberlite (Aaron) may be younger than the 47.5 Ma Mark kimberlite. The economically important Panda kimberlite is precisely dated in this study to be 53.3±0.6 Ma using the phlogopite isochron method, and up to six additional kimberlites from the central Ekati property have Early Eocene ages indistinguishable from that of Panda, including the Koala and Koala North occurrences. Late Paleocene 55-56 Ma kimberlite magmatism, represented by the Diavik kimberlite pipes adjacent to the southeastern Ekati property, is shown to extend onto the southeastern Ekati property and includes three, and possibly four, kimberlites. A precise eight-point phlogopite isochron for the Cobra South kimberlite yields an emplacement age of 59.7±0.4 Ma; eight other kimberlites from across the Ekati property have similar Late Paleocene Rb-Sr model ages. The addition of 27 new emplacement ages for kimberlites from the Ekati property confirms that kimberlite magmatism from the central Slave Province is geologically young, despite ages ranging back to Cambrian time from elsewhere in the Slave Province. With the available geochronologic database, Lac de Gras kimberlites with the highest diamond potential are currently restricted to the 51-53 and 55-56 Ma periods of kimberlite magmatism.

  20. Emplacement Gantry Gap Analysis Study

    International Nuclear Information System (INIS)

    Thornley, R.

    2005-01-01

    To date, the project has established important to safety (ITS) performance requirements for structures, systems, and components (SSCs) based on the identification and categorization of event sequences that may result in a radiological release. These performance requirements are defined within the ''Nuclear Safety Design Bases for License Application'' (NSDB) (BSC 2005 [DIRS 171512], Table A-11). Further, SSCs credited with performing safety functions are classified as ITS. In turn, assurance that these SSCs will perform as required is sought through the use of consensus codes and standards. This gap analysis is based on the design completed for license application only. Accordingly, identification of ITS SSCs beyond those defined within the NSDB are based on designs that may be subject to further development during detail design. Furthermore, several design alternatives may still be under consideration to satisfy certain safety functions, and final selection will not be determined until further design development has occurred. Therefore, for completeness, alternative designs currently under consideration will be discussed throughout this study. This gap analysis will evaluate each code and standard identified within the ''Emplacement Gantry ITS Standards Identification Study'' (BSC 2005 [DIRS 173586]) to ensure each ITS performance requirement is fully satisfied. When a performance requirement is not fully satisfied, a gap is highlighted. This study will identify requirements to supplement or augment the code or standard to meet performance requirements. Further, this gap analysis will identify nonstandard areas of the design that will be subject to a design development plan. Nonstandard components and nonstandard design configurations are defined as areas of the design that do not follow standard industry practices or codes and standards. Whereby, assurance that an SSC will perform as required may not be readily sought though the use of consensus standards. This

  1. Heat transfer effects in vertically emplaced high level nuclear waste container

    International Nuclear Information System (INIS)

    Moujaes, S.F.; Lei, Y.M.

    1994-01-01

    Modeling free convection heat transfer in an cylindrical annular enclosure is still an active area of research and an important problem to be addressed in the high level nuclear waste repository. For the vertically emplaced waste container, the air gap which is between the container shell and the rock borehole, have an important role of dissipating heat to surrounding rack. These waste containers are vertically emplaced in the borehole 300 meters below ground, and in a horizontal grid of 30 x 8 meters apart. The borehole will be capped after the container emplacement. The expected initial heat generated is between 3--4.74 kW per container depending on the type of waste. The goal of this study is to use a computer simulation model to find the borehole wall, air-gap and the container outer wall temperature distributions

  2. Emplacement and retrieval equipment design considerations for a repository in salt

    International Nuclear Information System (INIS)

    Nair, B.R.; Bahorich, R.J.

    1987-01-01

    The current design concept for the disposal of nuclear high level waste packages in a repository in salt is based on the emplacement of individual packages in vertical boreholes in the underground mine floor. A key requirement is that the waste packages be capable of being retrieved during the last 26 years of the 76-year repository operating period. The unique design considerations relating to the retrieval of waste packages emplaced in bedded salt are presented in this paper. The information is based on the experience developed during the design of vertical emplacement and retrieval equipment in support of the Sandia Defense High Level Waste experiments at the Waste Isolation Pilot Plant. Also included are the impact of retrievability on the design of the equipment, the special salt cutting technology that was developed for this application, and a description of the equipment

  3. Equipment for the emplacement of heat-producing waste in long horizontal boreholes

    International Nuclear Information System (INIS)

    Young, K.D.; Scully, L.W.; Fisk, A.; deBakker, P.; Friant, J.; Anderson, A.

    1983-01-01

    Emplacement of heat-producing waste in long horizontal holes may offer several technical and economic advantages over shallow vertical hole emplacement. Less of the host rock suffers damage as a result of drift construction; the heat from the waste can be isolated from the access drifts for long periods of time; and the amount of rock which must be excavated is much less than in traditional disposal scenarios. One of the major reasons that has been used to reject the long hole concept in the past and adhere to the shallow vertical hole concept is the equipment required to drill the holes and to emplace and retrieve the waste. Such equipment does not currently exist. It clearly is more difficult to drill a 600 to 1000 foot horizontal hole, possibly 3 to 4 feet in diameter, and place a canister of waste at the end of it than to drill a 30 foot vertical hole and lower the waste to the bottom. A liner, for emplacement hole stabilization, appears to be feasible by adapting existing technology for concrete slip forming or jacking in a steel liner. The conceptual design of the equipment to drill long horizontal holes, emplace waste and retrieve waste will be discussed. Various options in concept will be presented as well as their advantages and disadvantages. The operating scenario of the selected concept will be described as well as solutions to potential problems encountered

  4. Equipment for the emplacement of heat-producing waste in long horizontal boreholes

    International Nuclear Information System (INIS)

    Young, K.D.; Fisk, A.; Friant, J.; Scully, L.W.

    1983-01-01

    Emplacement of heat-producing waste in long horizontal holes may offer several technical and economic advantages over shallow vertical hole emplacement. Less of the host rock suffers damage as a resul of drift construction; the heat from the waste can be isolated from the access drifts for long periods of time; and the amount of rock which must be excavated is much less than in traditional disposal scenarios. One of the major reasons that has been used to reject the long hole concept in the past and adhere to the shallow vertical hole concept is the equipment required to drill the holes and to emplace and retrieve the waste. Such equipment does not currently exist. It clearly is more difficult to drill a 600 to 100 foot horizontal hole, possibly 3 to 4 feet in diameter, and place a canister of waste at the end of it than to drill a 30 foot vertical hole and lower the waste to the bottom. A liner, for emplacement hole stabilization, appears to be feasible by adapting existing technology for concrete slip forming or jacking in a steel liner. The conceptual design of the equipment to drill long horizontal holes, emplace waste and retrieve waste is discussed. Various options in concept are presented as well as their advantages and disadvantages. The operating scenario of the selected concept is described as well as solutions to potential problems encountered

  5. Strike-slip pull-apart process and emplacement of Xiangshan uranium-producing volcanic basin

    International Nuclear Information System (INIS)

    Qiu Aijin; Guo Lingzhi; Shu Liangshu

    2001-01-01

    Xiangshan volcanic basin is one of the famous uranium-producing volcanic basins in China. Emplacement mechanism of Xiangshan uranium-producing volcanic basin is discussed on the basis of the latest research achievements of deep geology in Xiangshan area and the theory of continental dynamics. The study shows that volcanic activity in Xiangshan volcanic basin may be divided into two cycles, and its emplacement is controlled by strike-ship pull-apart process originated from the deep regional faults. Volcanic apparatus in the first cycle was emplaced in EW-trending structure activated by clockwise strike-slipping of NE-trending deep fault, forming the EW-trending fissure-type volcanic effusion belt. Volcanic apparatus in the second cycle was emplaced at junction points of SN-trending pull-apart structure activated by sinistral strike-slipping of NE-trending deep faults and EW-trending basement faults causing the center-type volcanic magma effusion and extrusion. Moreover, the formation mechanism of large-rich uranium deposits is discussed as well

  6. Operational considerations in drift emplacement of waste packages

    International Nuclear Information System (INIS)

    Benton, H.A.

    1993-01-01

    This paper discusses the operational considerations as well as the advantages and disadvantages of emplacing waste packages in drifts in a repository. The considerations apply particularly to the potential repository for spent nuclear fuel and high-level waste glass at Yucca Mountain, although most of the considerations and the advantages and disadvantages discussed in this paper do not necessarily represent the official views of the DOE or of the Management and Operations Contractor, since most of these considerations are still under active discussion and the final decisions will not be made for some time - perhaps years. This paper describes the issues, suggests some principles upon which decisions should be based, and states some of the most significant advantages and disadvantages of the emplacement modes, and the associated waste package types and thermal loadings

  7. Effects of igneous intrusions on the petroleum system: a review

    NARCIS (Netherlands)

    Senger, Kim; Millett, John; Planke, Sverre; Ogata, Kei; Eide, Christian Haug; Festøy, Marte; Galland, Olivier; Jerram, Dougal A.

    2017-01-01

    Igneous intrusions feature in many sedimentary basins where hydrocarbon exploration and production is continuing. Owing to distinct geophysical property contrasts with siliciclastic host rocks (e.g., higher Vp, density and resistivity than host rocks), intrusions can be easily delineated within data

  8. Extent and impact of Cretaceous magmatism on the formation and evolution of Jurassic oceanic crust in the western Pacific

    Science.gov (United States)

    Feng, H.; Lizarralde, D.; Tominaga, M.; Hart, L.; Tivey, M.; Swift, S. A.

    2015-12-01

    Multi-channel seismic (MCS) images and wide-angle sonobuoy data acquired during a 2011 cruise on the R/V Thomas G. Thompson (TN272) show widespread emplacement of igneous sills and broadly thickened oceanic Layer 2 through hundreds of kilometers of oceanic crust in one of the oldest ocean basins in the western Pacific, a region known as the Jurassic Quiet Zone (JQZ). Oceanic crust from the JQZ has grown through at least two main magmatic phases: It was formed by mid-ocean ridge processes in the Jurassic (at ~170 Ma), and then it was added to by a substantial Cretaceous magmatic event (at ~75-125 Ma). The scale of Cretaceous magmatism is exemplified by massive seafloor features such as the Ontong Java Plateau, Mid-Pacific Mountains, Marshall-Gilbert Islands, Marcus-Wake Seamount Chain, and numerous guyots, seamounts, and volcaniclastic flows observed throughout the region. We use seismic data to image heavily intruded and modified oceanic crust along an 800-km-long transect through the JQZ in order to examine how processes of secondary crustal growth - including magmatic emplacement, transport, and distribution - are expressed in the structure of modified oceanic crust. We also model gravity anomalies to constrain crustal thickness and depth to the Moho. Our observations suggest that western Pacific crust was modified via the following modes of emplacement: (a) extrusive seafloor flows that may or may not have grown into seamounts, (b) seamounts formed through intrusive diking that pushed older sediments aside during their formation, and (c) igneous sills that intruded sediments at varying depths. Emplacement modes (a) and (b) tend to imply a focused, pipe-like mechanism for melt transport through the lithosphere. Such a mechanism does not explain the observed broadly distributed intrusive emplacement of mode (c) however, which may entail successive sill emplacement between igneous basement and sediments thickening oceanic Layer 2 along ~400 km of our seismic line

  9. Thermal/thermomechanical analyses for the room region with horizontal and vertial modes of emplacement

    International Nuclear Information System (INIS)

    1988-01-01

    Extensive thermal/thermomechanical analyses of the Site Characterization Plan-Conceptual Design at the Deaf Smith county Site, Texas, have been carried out for the room region with horizontal and vertical modes of emplacement. The main purpose of this study is to make a good comparison between these two modes of emplacement in this region. Homogeneous and nonhomogeneous strata under isothermal or transient temperature conditions cases were considered in the analyses. Furthermore, various pillar widths for the vertical mode emplacement were also taken into consideration. Only spent fuel (SF) waste was considered in this study. Finite element method was used throughout the analyses. The thermal responses were evaluated using SPECTROM-41 while the thermomechanical responses were calculated using SPECTROM-32. Thermal and thermomechanical comparisons between the two modes of emplacement for various cases were presented in this paper

  10. Petrology and geochemistry of igneous inclusions in recent Merapi deposits

    DEFF Research Database (Denmark)

    Chadwick, J.P.; Troll, V.R.; Waight, Tod Earle

    2013-01-01

    Recent basaltic-andesite lavas from Merapi volcano contain abundant and varied igneous inclusions suggesting a complex sub-volcanic magmatic system for Merapi volcano. In order to better understand the processes occurring beneath Merapi, we have studied this suite of inclusions by petrography, ge...

  11. Magnetic Susceptibility as a Tool for Investigating Igneous Rocks—Experience from IODP Expedition 304

    Directory of Open Access Journals (Sweden)

    Roger C. Searle

    2008-07-01

    Full Text Available Continuous measurements of magnetic susceptibility have been commonly used on Ocean Drilling Program (ODP and Integrated Ocean Drilling Program (IODPexpeditions to study minor lithological variations (forexample, those related to climatic cycles in sedimentary rocks, but they have been less frequently used on igneous rocks, although important post-cruise studies have utilized them (e.g., Ildefonse and Pezard, 2001. Here I report its use (and that of the closely related electrical conductivity on IODP Expedition 304 to examine igneous crustal rocks. Expedition 304/305 targeted the Atlantis Massif, an oceanic core complex on the Mid-Atlantic Ridge, and recovered a suite of igneous rocks comprising mainly gabbros, troctolites, and some diabases (Blackman et al., 2006; Ildefonse et al., 2006, 2007; IODP Expeditions 304 and 305 Scientists, 2005. Shipboard measurements (on D/V JOIDES Resolution of physical properties were made to characterize lithological units and alteration products, to correlate cored material with down-hole logging data, and to interpret broader-scale geophysical data.

  12. Geochronological and mineralogical constraints on depth of emplacement and ascencion rates of epidote-bearing magmas from northeastern Brazil

    Science.gov (United States)

    Sial, Alcides N.; Vasconcelos, Paulo M.; Ferreira, Valderez P.; Pessoa, Ricardo R.; Brasilino, Roberta G.; Morais Neto, João M.

    2008-10-01

    Calc-alkalic to high-K calc-alkalic granitoid plutons in the Borborema province, northeastern Brazil, have been studied to constrain depth of emplacement by mineralogical and geological methods and to estimate upward magma transport rate based on partial dissolution of magmatic epidote. Laser-probe incremental heating 40Ar/ 39Ar dating of biotite and hornblende single crystals from the Neoproterozoic Tavares and Brejinho high-K calc-alkalic magmatic epidote (mEp)-bearing plutons reveals age differences of around 60 M.y. between these two minerals in each of these two intrusions. These data suggest solidification at relatively great depth followed by prolonged cooling interval between the closure temperatures of biotite and hornblende. Al-in-hornblende barometry indicates that hornblende in several mEp-bearing plutons in the Transversal Domain of the Borborema province solidified at 5 to 7 kbar, whereas in the Seridó and Macururé terranes, solidification pressures range from 3 to 4 kbar. Partial dissolution of epidote indicates very rapid upward transport. Partial corrosion occurred during 15-35 years (Cachoerinha-Salgueiro terrane), 10-30 years (Alto Pajeú), 15 years (Seridó), and 10 years (Macururé) corresponding to upward transport rates of 450-1300, 650-1050, 1200, and 1800 m/year respectively in these four terranes. Rapid upward magma migration in most cases was probably facilitated by diking simultaneous with regional shearing.

  13. Reexamination of the source material of acid igneous rocks, based on the selected Sr isotopic data

    International Nuclear Information System (INIS)

    Kagami, Hiroo; Shuto, Kenji; Gorai, Masao

    1975-01-01

    The relation between the ages and the initial strontium isotopic compositions obtained from acid igneous rocks by the whole-rock isochron method is re-examined, on the basis of the selected data. The points based on the data having high values of standard deviation (on the isochrons) show considerable scattering. This is probably ascribed to admixture of sialic materials, or secondary alteration and other geologic causes. The points based on the data having lower values of standard deviation (sigma value: 0.0001 - 0.0019), on the other hand, are evidently plotted within a narrow region just above the presumed Sr evolutional region of the source material of oceanic tholeiites. It is noteworthy that the former region meets the latter region at an earlier stage of the evolutional history of the earth (about 40 x 10 8 yrs. ago or older). It may be conceivable that the former region is the Sr evolutional region of the source material of acid igneous rocks. Considering from the inclination of the above Sr evolutional region, the source material of most of acid igneous rocks may possibly be a certain basic material, chemically similar to the continental tholeiitic basalts or basaltic andesites. On the other hand, the source material of a few acid igneous rocks with low initial strontium isotopic ratios may be a certain basic material resembling the oceanic tholeiites. Another possibility is that these acid igneous rocks and oceanic tholeiites may have been formed, under different physical conditions, directly from a certain common source material presumably of peridotitic composition. (auth.)

  14. PETROS - Worldwide Databank of Major Element Chemical Analyses of Igneous Rocks

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — PETROS is a worldwide data bank of major element chemical analyses of igneous rocks compiled for research and teaching purposes by Dr. Felix Mutschler and Staff at...

  15. Petrogenesis and metallogenesis of the Wajilitag and Puchang Fe-Ti oxide-rich intrusive complexes, northwestern Tarim Large Igneous Province

    Science.gov (United States)

    Zhang, Dongyang; Zhang, Zhaochong; Huang, He; Cheng, Zhiguo; Charlier, Bernard

    2018-04-01

    The Wajilitag and Puchang intrusive complexes of the Tarim large igneous province (TLIP) are associated with significant resources of Fe-Ti oxide ores. These two mafic-ultramafic intrusions show differences in lithology and mineral chemistry. Clinopyroxenite and melagabbro are the dominant rock types in the Wajilitag complex, whereas the Puchang complex is generally gabbroic and anorthositic in composition with minor plagioclase-bearing clinopyroxenites in the marginal zone. Disseminated Fe-Ti oxide ores are found in the Wajilitag complex and closely associated with clinopyroxenites, whereas the Puchang complex hosts massive to disseminated Fe-Ti oxide ores mainly within its gabbroic rocks. The Wajilitag intrusive rocks are characterized by a restricted range of initial 87Sr/86Sr ratios (0.7038-0.7048) and positive εNd(t) (+0.04 - +3.01), indicating insignificant involvement of continental crustal contamination. The slightly higher initial 87Sr/86Sr ratios (0.7039-0.7059) and lower εNd(t) values (-1.05 - +2.35) of the Puchang intrusive rocks also suggest that the isotopic characteristics was controlled primarily by their mantle source, rather than by crustal contamination. Both complexes have Sr-Nd isotopic compositions close the neighboring kimberlitic rocks and their hosted mantle xenoliths in the TLIP. This indicates that the ferrobasaltic parental magmas were most probably originated from partial melting of a metasomatized subcontinental lithospheric mantle, modified recently with subduction-related materials by the impingement of the ascending mantle plume. The recycled subduction-related materials preserved in the lithospheric mantle could play a key role in the formation of the parental Fe-rich magmas in the context of an overall LIP system. The distinct variations in mineral assemblage for each complex and modeled results indicated that the Wajilitag and Puchang complexes experienced different crystallization path. Fe-Ti oxides in Wajilitag joined the

  16. Thermally-assisted Magma Emplacement Explains Restless Calderas.

    Science.gov (United States)

    Amoruso, Antonella; Crescentini, Luca; D'Antonio, Massimo; Acocella, Valerio

    2017-08-11

    Many calderas show repeated unrest over centuries. Though probably induced by magma, this unique behaviour is not understood and its dynamics remains elusive. To better understand these restless calderas, we interpret deformation data and build thermal models of Campi Flegrei caldera, Italy. Campi Flegrei experienced at least 4 major unrest episodes in the last decades. Our results indicate that the inflation and deflation of magmatic sources at the same location explain most deformation, at least since the build-up of the last 1538 AD eruption. However, such a repeated magma emplacement requires a persistently hot crust. Our thermal models show that this repeated emplacement was assisted by the thermal anomaly created by magma that was intruded at shallow depth ~3 ka before the last eruption. This may explain the persistence of the magmatic sources promoting the restless behaviour of the Campi Flegrei caldera; moreover, it explains the crystallization, re-melting and mixing among compositionally distinct magmas recorded in young volcanic rocks. Our model of thermally-assisted unrest may have a wider applicability, possibly explaining also the dynamics of other restless calderas.

  17. Grenvillian vs Pan-African tectonic evolution in the Gamburtsev Province of East Antarctica

    Science.gov (United States)

    Ferraccioli, F.; Guochao, W.; Finn, C.; Bell, R. E.

    2017-12-01

    The Gamburtsev Subglacial Mountains in interior East Antarctica are underlain by 50-60 km thick crust. In contrast, the Archean to Mesoproterozoic Mawson craton that occupies the Wilkes and Terre Adelie region features only 40-45 km thick crust. The Gamburtsev Province is underlain by 200 km thick lithoshere, as typically observed over Precambrian lithosphere that has not been substantially reworked during Phanerozoic subduction or collision. Ferraccioli et al., (2011) proposed that a segment of a stalled orogen (i.e. an orogen where widespread orogenic collapse and root delamination has not occurred) is preserved in the Gamburtsev Province and hypothesised that its origin relates to accretionary and subsequent collisional events at ca 1 Ga, linked to the assembly of Rodinia. However, passive seismic interpretations indicate that crustal thickening may relate instead to Pan-African age assembly of Gondwana (at ca 550 Ma). Here we interpret a set of enhanced magnetic and gravity images, depth to magnetic and gravity sources and 2D and forward and inverse models to characterise the crustal architecture of the Gamburtsev Province. Enhanced aeromagnetic images reveal a system of subglacial faults that segment the Gamburtsev Province into three distinct geophysical domains, the northern, central and southern domains. Apparent offsets in high-frequency magnetic anomalies within the central domain are interpreted as revealing a transpressional fault system parallel to the previously proposed Gamburtsev Suture. Our magnetic and gravity model, combined with independent constraints from sediment provenance ages, is interpreted as revealing arc and back arc terranes of inferred Grenvillian age in the northern and Central domains of the Gambrurtsev Province. Distinct magnetic anomalies correspond to inferred Paleoproterozoic crust that may have affinities with the Lambert Terrane and the South Pole Province, an inferred Mesoproterozoic (1.6-1.4 Ga?) igneous province. We

  18. Response of zircon to melting and metamorphism in deep arc crust, Fiordland (New Zealand): implications for zircon inheritance in cordilleran granites

    Science.gov (United States)

    Bhattacharya, Shrema; Kemp, A. I. S.; Collins, W. J.

    2018-04-01

    The Cretaceous Mount Daniel Complex (MDC) in northern Fiordland, New Zealand was emplaced as a 50 m-thick dyke and sheet complex into an active shear zone at the base of a Cordilleran magmatic arc. It was emplaced below the 20-25 km-thick, 125.3 ± 1.3 Ma old Western Fiordland Orthogneiss (WFO) and is characterized by metre-scale sheets of sodic, low and high Sr/Y diorites and granites. 119.3 ± 1.2 Ma old, pre-MDC lattice dykes and 117.4 ± 3.1 Ma late-MDC lattice dykes constrain the age of the MDC itself. Most dykes were isoclinally folded as they intruded, but crystallised within this deep-crustal, magma-transfer zone as the terrain cooled and was buried from 25 to 50 km (9-14 kbar), based on published P-T estimated from the surrounding country rocks. Zircon grains formed under these magmatic/granulite facies metamorphic conditions were initially characterized by conservatively assigning zircons with oscillatory zoning as igneous and featureless rims as metamorphic, representing 54% of the analysed grains. Further petrological assignment involved additional parameters such as age, morphology, Th/U ratios, REE patterns and Ti-in-zircon temperature estimates. Using this integrative approach, assignment of analysed grains to metamorphic or igneous groupings improved to 98%. A striking feature of the MDC is that only 2% of all igneous zircon grains reflect emplacement, so that the zircon cargo was almost entirely inherited, even in dioritic magmas. Metamorphic zircons of MDC show a cooler temperature range of 740-640 °C, reflects the moderate ambient temperature of the lower crust during MDC emplacement. The MDC also provides a cautionary tale: in the absence of robust field and microstructural relations, the igneous-zoned zircon population at 122.1 ± 1.3 Ma, derived mostly from inherited zircons of the WFO, would be meaningless in terms of actual magmatic emplacement age of MDC, where the latter is further obscured by younger (ca. 114 Ma) metamorphic overgrowths

  19. A modified time-temperature relationship for titanomagnetite and its application to igneous erratic boulders in Hachijo Island, Japan

    Science.gov (United States)

    Tonosaki, T.; Nakamura, N.; Goto, K.; Sato, T.; Watanabe, M.

    2016-12-01

    On land along shore line in an island all over the world, there are many huge boulders which seem that they had been broken and transported by errastic events (such as extreme waves). The presence of boulders on land provides geological evidence that the region had been suffered by ancient tsunami or storm waves, establishing the evaluation of risk-management policies for future disasters. In volcanic island of Hachijo, Japan, there are huge (>5000 kg) andesitic boulder (20 m altitude high), and basaltic boulders (4 m altitude high) which seem that they had been broken from an outcrop and emplaced from it. Because radiocarbon dating can not be applied to volcanic rocks, a magnetic viscous dating might be powerful tool to determine the rotation history of rocks. Tyson Smith and Vrosub (1994) succeeded in revealing the age of landslide basaltic rocks by geological evidence, using Pullaiah's time-temperature monogram by Neel's relaxation theory of single domain (SD) particles of magnetite (Pullaiah et al. 1975). However, our application of this monogram to igneous boulders fails to determine the age due to a different magnetic mineralogy including titanomagnetite. Therefore, by introducing a modified monogram for single domain particles of titanomagnetite, we tried to reveal a possible reworked age of the boulders. However, our boulders still fail to identify the reworked age. In this presentation, we will present our current situation of the problem and a working hypothesis to solve it.

  20. Emplacement technology for the direct disposal of spent fuel into deep vertical boreholes

    International Nuclear Information System (INIS)

    Bollingerfehr, W.; Filbert, W.; Wehrmann, J.

    2008-01-01

    In the early sixties it was decided to investigate salt formations on its suitability to host heat generating radioactive waste in Germany. In the reference repository concept consequently the emplacement of vitrified waste canisters in deep vertical boreholes inside a salt mine was considered whereas spent fuel should be disposed of in self shielding casks (type POLLUX) in horizontal drifts. The POLLUX casks, 65 t heavy carbon steel casks, will be laid down on the floor of a horizontal drift in one of the disposal zones to be constructed in the salt dome at the 870 m level. The space between casks and drift walls will be backfilled with crushed salt. The transport, the handling und the emplacement of POLLUX casks were subject of successfully performed demonstration and in situ tests in the nineties and resulted in an adjustment of the atomic law. The borehole disposal concept comprises the emplacement of unshielded canisters with vitrified HLW in boreholes with a diameter of 60 cm and a depth of up to 300 m. In order to facilitate the fast encapsulation of the waste canister by the host rock (rock salt), no lining of the boreholes is planned. With regard to harmonize and optimize the emplacement technology for both categories of packages (vitrified waste and spent fuel) alternatives were developed. In this context the borehole emplacement technique for consolidated spent fuel as already foreseen for high-level reprocessing waste was reconsidered. This review resulted in the design of a new disposal package, a fuel rod canister (type 'BSK 3'), and an appropriate modified transport and emplacement technology. This concept (called BSK 3-concept) provides the following optimization possibilities: (i) A new steel canister of the same diameter (43 cm) as the standardized HLW canisters applied for high-level waste and compacted technological waste from reprocessing abroad can be filled with fuel rods of 3 PWR or 9 BWR fuel assemblies. (II) The standardized canister

  1. The Law of Element Abundance Relationships in Igneous Rocks Petrogenetically Associated with Fractional Crystallization

    Institute of Scientific and Technical Information of China (English)

    汪云亮; 王旺章

    1991-01-01

    Reported in this paper are:1)the law of element abundance relationships:element abun-dances are of power function with each other in an igneous rock petrogenetically associated with fractional crystallization,2)deduction of the law and relevant parameters:abundance relationship constant(a°) and phase constant? from Henry's law and the law of mass conservation,3)the data basis and evidence of the law of element abundance relationships,4)establishment of the equa-bions for element abundance relationships in igneous rocks formed from the same parental magma during the same fractional crystallization stage ,and all measurable parameters involved in the equations.

  2. Experimental constraints on partitioning and zoning of phosphorus in igneous olivine

    Science.gov (United States)

    Ersoy, Ö.; Nikogosian, I.; Mason, P. R. D.; Van Westrenen, W.; van Bergen, M.

    2017-12-01

    Fast diffusion and homogenization of divalent cations hamper the preservation of original chemical compositions and zoning patterns of igneous olivine phenocrysts. Sluggish intracrystalline diffusion of phosphorus in igneous olivine on the other hand allows the complex zoning patterns to be retained, making it a crucial element for reconstruction of cooling histories and evolution of the host magma. Crystallization rate variations, diffusion controlled growth or compositional controls on melt-mineral partitioning have been put forward as mechanisms controlling zoning of igneous olivine in phosphorus. Here, we investigate partitioning and zoning of phosphorus in igneous olivines by a comparison of natural and experimentally grown olivines. We explore the importance of variable degrees of undercooling and cooling rates in crystallizing melt (M1) with a starting composition equivalent to that of an Italian high-potassium basalt (Tliq=1274 °C). We examine the extent of compositional control on partitioning by varying the amount of alkali enrichment in starting compositions that are otherwise equivalent to melt M1. Olivine crystallization experiments were conducted in rhenium capsules suspended in a vertical 1-atm gas-mixing furnace at Vrije Universiteit Amsterdam (VUA) with fO2 buffered at 1.4 to 1.7 log units below the Ni-NiO buffer. Sets of dynamic crystallization experiments with various degrees of undercooling and controlled cooling rate experiments with varying cooling rates were performed. We compare the results with our extensive EPMA and LA-ICPMS dataset on olivines from Italian K-rich mafic lavas and olivine hosted primitive melt inclusions (MIs). Phosphorus concentrations in the natural olivines reach 435 ppm P and MIs contain up to 2.2 wt.% P2O5. High resolution (1-4 µm per pixel) element maps show both fine oscillatory, patchy and large scale sector zoning in P, uncorrelated with zoning in any other element. The MIs are almost always found in P-poor zones

  3. Magma emplacement in 3D

    Science.gov (United States)

    Gorczyk, W.; Vogt, K.

    2017-12-01

    Magma intrusion is a major material transfer process in Earth's continental crust. Yet, the mechanical behavior of the intruding magma and its host are a matter of debate. In this study, we present a series of numerical thermo-mechanical experiments on mafic magma emplacement in 3D.In our model, we place the magmatic source region (40 km diameter) at the base of the mantle lithosphere and connect it to the crust by a 3 km wide channel, which may have evolved at early stages of magmatism during rapid ascent of hot magmatic fluids/melts. Our results demonstrate continental crustal response due to magma intrusion. We observe change in intrusion geometries between dikes, cone-sheets, sills, plutons, ponds, funnels, finger-shaped and stock-like intrusions as well as injection time. The rheology and temperature of the host-rock are the main controlling factors in the transition between these different modes of intrusion. Viscous deformation in the warm and deep crust favours host rock displacement and magma pools along the crust-mantle boundary forming deep-seated plutons or magma ponds in the lower to middle-crust. Brittle deformation in the cool and shallow crust induces cone-shaped fractures in the host rock and enables emplacement of finger- or stock-like intrusions at shallow or intermediate depth. A combination of viscous and brittle deformation forms funnel-shaped intrusions in the middle-crust. Low-density source magma results in T-shaped intrusions in cross-section with magma sheets at the surface.

  4. Sediment mechanical response due to emplacement of a waste canister

    International Nuclear Information System (INIS)

    Karnes, C.H.; Dawson, P.R.; Silva, A.J.; Brown, W.T.

    1980-01-01

    Preliminary studies have been conducted to determine the interaction between a waste canister and seabed sediment during and after emplacement. Empirical and approximate methods for determining the depth reached by a freefall penetrator indicate that a boosted penetrator emplacement method may be necessary. Hole closure is necessary, but has not been verified because calculations and laboratory experiments show sensitivity to boundary conditions which control the degree of dynamic hole closure. Laboratory studies show that closure will take place by creep deformation but closure times in seabed environments are uncertain. For assumed thermomechanical properties of sediments, it is shown that a heat generating waste canister will probably not move a significant distancce during the heat generation period

  5. From steep feeders to tabular plutons - Emplacement controls of syntectonic granitoid plutons in the Damara Belt, Namibia

    Science.gov (United States)

    Hall, Duncan; Kisters, Alexander

    2016-01-01

    Granitoid plutons in the deeply eroded south Central Zone of the Damara Belt in Namibia commonly show tabular geometries and pronounced stratigraphic controls on their emplacement. Subhorizontal, sheet-like pluton geometries record emplacement during regional subhorizontal shortening, but the intrusion of spatially and temporally closely-related granitoid plutons at different structural levels and in distinct structural settings suggests independent controls on their levels of emplacement. We describe and evaluate the controls on the loci of the dyke-to-sill transition that initiated the emplacement of three syntectonic (560-530 Ma) plutons in the basement-cover stratigraphy of the Erongo region. Intrusive relationships highlight the significance of (1) rigidity anisotropies associated with competent sedimentary packages or pre-existing subhorizontal granite sheets and (2) rheological anisotropies associated with the presence of thick ductile marble horizons. These mechanical anisotropies may lead to the initial deflection of steep feeder conduits as well as subsequent pluton assembly by the repeated underaccretion of later magma batches. The upward displacement of regional isotherms due to the heat advection associated with granite emplacement is likely to have a profound effect on the mechanical stratification of the upper crust and, consequently, on the level at which granitoid pluton emplacement is initiated. In this way, pluton emplacement at progressively shallower crustal depths may have resulted in the unusually high apparent geothermal gradients recorded in the upper crustal levels of the Damara Belt during its later evolution.

  6. The East Greenland rifted volcanic margin

    Directory of Open Access Journals (Sweden)

    C. Kent Brooks

    2011-12-01

    the emplacement of small volumes of basalts of the Vindtoppen Formation to the south of Scoresby Sund.Although the basalts were extruded close to sea level, this part of East Greenland is a plateau raised to c. 2 km, but the timing of uplift is controversial. Superimposed on the plateau is a major dome at Kangerlussuaq.East Greenland presents a rich interplay between magmatic and tectonic events reflecting the birth of the North Atlantic Ocean. It was active over a much longer period (36 Ma than other parts of the province (5 Ma in the Hebrides, Northern Ireland and the Faroe Islands and contains a wider range of products, including carbonatites, and felsic rocks tend to be granitic rather than syenitic. As expected, there are many similarities with Iceland, the present-day expression of activity in the province. Differences are readily explained by higher production rates and the thicker lithospheric lid during the early stages of development in East Greenland. The igneous and related activity clearly results from plate-tectonic factors, but the relationship is not understood in detail. In particular, the nature of the underlying mantle processes, primarily the presence or absence of a plume, is still not resolved.

  7. Breccia pipes in the Karoo Basin, South Africa, as conduits for metamorphic gases to the Early Jurassic atmosphere

    Science.gov (United States)

    Silkoset, Petter; Svensen, Henrik; Planke, Sverre

    2014-05-01

    The Toarcian (Early Jurassic) event was manifested by globally elevated temperatures and anoxic ocean conditions that particularly affected shallow marine taxa. The event coincided with the emplacement of the vast Karoo-Ferrar Large Igneous Province. Among the suggestions for trigger mechanisms for the climatic perturbation is metamorphic methane generation from black shale around the sills in the Karoo Basin, South Africa. The sill emplacement provides a mechanism for voluminous in-situ production and emission of greenhouse gases, and establishes a distinct link between basin-trapped and atmospheric carbon. In the lower stratigraphic levels of the Karoo Basin, black shales are metamorphosed around sills and the sediments are cut by a large number of pipe structures with metamorphic haloes. The pipes are vertical, cylindrical structures that contain brecciated and baked sediments with variable input of magmatic material. Here, we present borehole, petrographic, geochemical and field data from breccia pipes and contact aureoles based on field campaigns over a number of years (2004-2014). The metamorphism around the pipes show equivalent metamorphic grade as the sediments around nearby sills, suggesting a more prominent phreatomagmatic component than previously thought. The stratigraphic position of pipes and the breccia characteristics strengthens the hypothesis of a key role in the Toarcian carbon isotope excursion.

  8. Geology and U-Pb geochronology of the Kipawa Syenite Complex - a thrust related alkaline pluton - and adjacent rocks in the Grenville Province of western Quebec

    Energy Technology Data Exchange (ETDEWEB)

    Van Breemen, O.; Currie, K.L. [Geological Survey of Canada, Ottawa, Ontario (Canada)]. E-mail: ovanbree@nrcan.gc.ca

    2004-07-01

    The Kipawa Syenite Complex, a thin, folded sheet of amphibole syenite, quartz syenite and minor nepheline syenite, lies along a west-vergent thrust separating a lower slice comprising the Kikwissi granodiorite and biotite tonalite dated at 2717 {sub -11}{sup +15} Ma, and unconformably overlying metasedimentary rocks from an overlying slice containing the Red Pine Chute orthogneiss, an alkali granite gneiss, and the Mattawa Quartzite. The syenite complex, dated at 1033 {+-} 3 Ma, lies within the lower slice but has metasomatically altered the overlying slice. Texturally guided U-Pb spot analyses on partially metasomatised zircons from the alkali granite gneiss yield a cluster of {sup 207}G'Pb/{sup 206}Pb ages at 1389 {+-} 8 Ma, interpreted as the time of igneous crystallization and four ages overlapping the time of syenite emplacement, interpreted as in situ, metasomatic growth. The highest structural slice comprises garnet amphibolite separated from lower slices by the Allochthon Boundary Thrust. Metamorphic grade increases upward from greenschist grade in the biotite tonalite to amphibolite grade (690 {sup o}C, 9 kbar (1 kbar = 100 MPa)) at the lower boundary of the alkali granite. Emplacement of the Kipawa Syenite Complex took place after assembly of the thrust stack had begun and after emplacement of the allochthon or hot slab responsible for the inverted metamorphic gradient. Origin of the syenite is tentatively ascribed to anatexis of material metasomatized by flow of alkaline solutions along a major shear surface. Crystallization of new zircon in the margins of the syenite shows that metasomatism continued from ca. 1035 to 990 Ma, redistributing alkalies, fluorine, rare-earth elements and zirconium. (author)

  9. Palaeomagnetism of the Cappadocian Volcanic Succession, Central Turkey: Major ignimbrite emplacement during two short (Miocene) episodes and Neogene tectonics of the Anatolian collage

    Science.gov (United States)

    Piper, J. D. A.; Koçbulut, F.; Gürsoy, H.; Tatar, O.; Viereck, L.; Lepetit, P.; Roberts, A. P.; Akpınar, Z.

    2013-07-01

    The Central Anatolian Volcanic Province in Cappadocia includes 13 high volume calc-alkaline ignimbrite sheets emplaced by plinian eruptions within a succession (the Ürgüp Formation) after ~ 10 Ma recording the last phase of Neotethyan subduction and accompanying emplacement of the Tauride orogen in southern Turkey. To evaluate magnetostratigraphy in the context of recent revisions of the chronostratigraphy we have extended palaeomagnetic investigation to 32 new sites yielding significant ChRM directions. Integrated rock magnetic and palaeomagnetic investigations identify magnetic remanence residing predominantly in Ti-poor titanomagnetites although secondary processes within the ignimbrite sheets, notably post-emplacement oxidation, have locally produced hematisation expressed by composite IRM spectra and variable reduction in intensity of magnetisation. The ignimbrite sheets possess weak anisotropies of magnetic susceptibility (AMS, mostly < 5%) describing tensors with axial distributions close to bedding and minimum axes predominantly perpendicular to this plane; collectively directions show weak imbrication correlating with palaeoflow during emplacement predominantly towards the north and east away from the Erdas Dağ, an inferred topographic palaeohigh at the southern margin of the basin. The precise control provided by magnetostratigraphy and radiometric age dating now shows that the bulk of Cappadocian ignimbrite magmatism was concentrated into two short episodes. An older Cardak Centre (Kavak Group and Zelve ignimbrites) produced in excess of 200 km3 of pyroclastic deposits during polarity chron C4r.1n between 9.31 and 9.43 Ma. Subsequent activity from the Acıgöl Centre further to the south west (Cemilköy, Gelveri, Gördeles, and Kızılkaya) produced in excess of 620 km3 of pyroclastic deposits during polarity chrons between 5.3 and 7.1 Ma. The younger İncesu ignimbrite was sourced in the Sultansazlığı pull-apart basin to the east during the Gauss

  10. Evaluating the Relationships Between NTNU/SINTEF Drillability Indices with Index Properties and Petrographic Data of Hard Igneous Rocks

    Science.gov (United States)

    Aligholi, Saeed; Lashkaripour, Gholam Reza; Ghafoori, Mohammad; Azali, Sadegh Tarigh

    2017-11-01

    Thorough and realistic performance predictions are among the main requisites for estimating excavation costs and time of the tunneling projects. Also, NTNU/SINTEF rock drillability indices, including the Drilling Rate Index™ (DRI), Bit Wear Index™ (BWI), and Cutter Life Index™ (CLI), are among the most effective indices for determining rock drillability. In this study, brittleness value (S20), Sievers' J-Value (SJ), abrasion value (AV), and Abrasion Value Cutter Steel (AVS) tests are conducted to determine these indices for a wide range of Iranian hard igneous rocks. In addition, relationships between such drillability parameters with petrographic features and index properties of the tested rocks are investigated. The results from multiple regression analysis revealed that the multiple regression models prepared using petrographic features provide a better estimation of drillability compared to those prepared using index properties. Also, it was found that the semiautomatic petrography and multiple regression analyses provide a suitable complement to determine drillability properties of igneous rocks. Based on the results of this study, AV has higher correlations with studied mineralogical indices than AVS. The results imply that, in general, rock surface hardness of hard igneous rocks is very high, and the acidic igneous rocks have a lower strength and density and higher S20 than those of basic rocks. Moreover, DRI is higher, while BWI is lower in acidic igneous rocks, suggesting that drill and blast tunneling is more convenient in these rocks than basic rocks.

  11. Post-igneous redistribution of components in eucrites

    Science.gov (United States)

    Phinney, W. C.; Lindstrom, D. J.; Mittlefehldt, D. W.; Martinez, R. R.

    1993-01-01

    In our analyses, we utilize a microdrilling technique that removes 40 to 100 micron diameter cores from mineral grains in thin sections analyzed by microprobe. The cores are then analyzed by INAA using the technique of Lindstrom. Three eucrites were selected for application of this analytical technique: monomict breccias Pasamonte and Stannern and unbrecciated EET90020. Pasamonte is among the most unequilibrated of the eucrites on the basis of zoning in pyroxenes and is considered to be an igneous rock not significantly affected by metamorphism. Stannern has igneous texture but its pyroxenes indicate some re-equilibration, although little, if any, recrystallization. EET90020 has a granulite texture and has been substantially recrystallized. Our sample of Pasamonte contains several clasts of different grain sizes ranging from glass to fine grained with diabasic texture containing lathy plagioclase, unexsolved pigeonite, and mesostasis. Cores were taken of the glass and from minerals and mesostases in six lithic clasts which normally allowed sampling of more than one phase per clast. Our sample of Stannern is also a breccia but with little difference in grain size between clasts and matrix. The plagioclase and pigeonite are blocky, twinned, and exsolved and coexist with a bit of mesostasis. Cores were taken of plagioclase and pigeonite with no attempt to distinguish separate clasts. EET90020 is a granular mixture of twinned plagioclase and pigeonite having rather uniform size and many triple junctions. Several cores were taken of both phases. Both clear and cloudy grains of plagioclase and pyroxene were sampled in all three eucrites.

  12. Palaeozoic and Mesozoic igneous activity in the Netherlands: a tectonomagmatic review

    NARCIS (Netherlands)

    Sissingh, W.

    To date, igneous rocks, either intrusive or extrusive, have been encountered in the Palaeozoic-Mesozoic sedimentary series of the Netherlands in some 65 exploration and production wells. Following 17 new isotopic K/Ar age determinations of the recovered rock material (amounting to a total of 28

  13. Longevity of Emplacement Drift Ground Support Materials for LA

    Energy Technology Data Exchange (ETDEWEB)

    D. Tang

    2003-09-16

    The purpose of this analysis report is to evaluate and document the inclusion or exclusion of the disruptive events features, events, and processes (FEPs) with respect to modeling used to support the total system performance assessment for license application (TSPA-LA). A screening decision, either ''Included'' or ''Excluded,'' is given for each FEP, along with the technical basis for screening decisions. This information is required by the U.S. Nuclear Regulatory Commission (NRC) at 10 CFR 63.114 (d), (e), and (f) [DIRS 156605]. The FEPs addressed in this report deal with both seismic and igneous disruptive events, such as fault displacements through the repository and an igneous intrusion into the repository. For included FEPs, this analysis summarizes the implementation of the FEP in TSPA-LA (i.e., how the FEP is included). For excluded FEPs, this analysis provides the technical basis for exclusion from TSPA-LA (i.e., why the FEP is excluded). Previous versions of this report were developed to support the total system performance assessments (TSPA) for various prior repository designs. This revision addresses the repository design for the license application (LA).

  14. Waste Handling and Emplacement Options for Disposal of Radioactive Waste in Deep Boreholes.

    Energy Technology Data Exchange (ETDEWEB)

    Cochran, John R.; Hardin, Ernest

    2015-11-01

    Traditional methods cannot be used to handle and emplace radioactive wastes in boreholes up to 16,400 feet (5 km) deep for disposal. This paper describes three systems that can be used for handling and emplacing waste packages in deep borehole: (1) a 2011 reference design that is based on a previous study by Woodward–Clyde in 1983 in which waste packages are assembled into “strings” and lowered using drill pipe; (2) an updated version of the 2011 reference design; and (3) a new concept in which individual waste packages would be lowered to depth using a wireline. Emplacement on coiled tubing was also considered, but not developed in detail. The systems described here are currently designed for U.S. Department of Energy-owned high-level waste (HLW) including the Cesium- 137/Strontium-90 capsules from the Hanford Facility and bulk granular HLW from fuel processing in Idaho.

  15. Origin of elevated water levels encountered in Pahute Mesa emplacement boreholes: Preliminary investigations

    International Nuclear Information System (INIS)

    Brikowski, T.; Chapman, J.; Lyles, B.; Hokett, S.

    1993-11-01

    The presence of standing water well above the predicted water table in emplacement boreholes on Pahute Mesa has been a recurring phenomenon at the Nevada Test Site (NTS). If these levels represent naturally perched aquifers, they may indicate a radionuclide migration hazard. In any case, they can pose engineering problems in the performance of underground nuclear tests. The origin of these elevated waters is uncertain. Large volumes of water are introduced during emplacement drilling, providing ample source for artificially perched water, yet elevated water levels can remain constant for years, suggesting a natural origin instead. In an effort to address the issue of unexpected standing water in emplacement boreholes, three different sites were investigated in Area 19 on Pahute Mesa by Desert Research Institute (DRI) staff from 1990-93. These sites were U-19az, U-19ba, and U-19bh. As of this writing, U-19bh remains available for access; however, nuclear tests were conducted at the former two locations subsequent to this investigations. The experiments are discussed in chronological order. Taken together, the experiments indicate that standing water in Pahute Mesa emplacement holes originates from the drainage of small-volume naturally perched zones. In the final study, the fluids used during drilling of the bottom 100 m of emplacement borehole U-19bh were labeled with a chemical tracer. After hole completion, water level rose in the borehole, while tracer concentration decreased. In fact, total mass of tracer in the borehole remained constant, while water levels rose. After water levels stabilized in this hole, no change in tracer mass was observed over two years, indicating that no movement of water out of the borehole is taking place (as at U- 19ba). Continued labeling tests of standing water are recommended to confirm the conclusions made here, and to establish their validity throughout Pahute Mesa

  16. Eruption and emplacement dynamics of a thick trachytic lava flow of the Sancy volcano (France)

    Science.gov (United States)

    Latutrie, Benjamin; Harris, Andrew; Médard, Etienne; Gurioli, Lucia

    2017-01-01

    A 70-m-thick, 2200-m-long (51 × 106 m3) trachytic lava flow unit underlies the Puy de Cliergue (Mt. Dore, France). Excellent exposure along a 400-m-long and 60- to 85-m-high section allows the flow interior to be accessed on two sides of a glacial valley that cuts through the unit. We completed an integrated morphological, structural, textural, and chemical analysis of the unit to gain insights into eruption and flow processes during emplacement of this thick silicic lava flow, so as to elucidate the chamber and flow dynamic processed that operate during the emplacement of such systems. The unit is characterized by an inverse chemical stratification, where there is primitive lava beneath the evolved lava. The interior is plug dominated with a thin basal shear zone overlying a thick basal breccia, with ramping affecting the entire flow thickness. To understand these characteristics, we propose an eruption model that first involves processes operating in the magma chamber whereby a primitive melt is injected into an evolved magma to create a mixed zone at the chamber base. The eruption triggered by this event first emplaced a trachytic dome, into which banded lava from the chamber base was injected. Subsequent endogenous dome growth led to flow down the shallow slope to the east on which the highly viscous (1012 Pa s) coulée was emplaced. The flow likely moved extremely slowly, being emplaced over a period of 4-10 years in a glacial manner, where a thick (>60-m) plug slid over a thin (5-m-thick) basal shear zone. Excellent exposure means that the Puy de Cliergue complex can be viewed as a case type location for understanding and defining the eruption and emplacement of thick, high-viscosity, silicic lava flow systems.

  17. EMPLACEMENT DRIFT ISOLATION DOOR CONTROL SYSTEM

    International Nuclear Information System (INIS)

    N.T. Raczka

    1998-01-01

    The purpose of this analysis is to review and refine key design concepts related to the control system presently under consideration for remotely operating the emplacement drift isolation doors at the potential subsurface nuclear waste repository at Yucca Mountain. This analysis will discuss the key design concepts of the control system that may be utilized for remotely monitoring, opening, and closing the emplacement drift isolation doors. The scope and primary objectives of this analysis are to: (1) Discuss the purpose and function of the isolation doors (Presented in Section 7.1). (2) Review the construction of the isolation door and other physical characteristics of the doors that the control system will interface with (Presented in Section 7.2). (3) Discuss monitoring and controlling the operation of the isolation doors with a digital control system (either a Programmable Logic Controller (PLC) system or a Distributed Control System (DCS)) (Presented in Section 7.3). (4) Discuss how all isolation doors can be monitored and controlled from a subsurface central control center (Presented in Section 7.4). This analysis will focus on the development of input/output (I/O) counts including the types of I/O, redundancy and fault tolerance considerations, and processor requirements for the isolation door control system. Attention will be placed on operability, maintainability, and reliability issues for the system operating in the subsurface environment with exposure to high temperatures and radiation

  18. Book Review: Potassic igneous rocks and associated gold-copper mineralization, Fourth edition (D. Muller and D.I. Groves)

    Science.gov (United States)

    Kelley, Karen D.

    2016-01-01

    The fourth edition of this comprehensive textbook, which succeeds those published in 1995, 1997, and 2000, very nicely summarizes the geochemical and petrological characteristics of potassic igneous rock complexes and the different tectonic settings in which they occur. The authors provide an overview and a classification of these rocks and they outline the geochemical differences between barren and mineralized potassic igneous complexes. Owing to the common association of potassic igneous rocks with many gold- and copper-rich ore deposits, this book will be of interest not only to research scientists but also to those exploring for major deposits in young and ancient terranes. In fact, there was a clear attempt by the authors to provide a good mix of theoretical discussions based on experimental work, with case studies that illustrate field and applied research.

  19. Evaluation of hydrologic isolation from evidence in mine openings in igneous and metamorphic rocks in the Maritime Provinces of Canada

    International Nuclear Information System (INIS)

    Martinez, J.D.

    1975-09-01

    Conditions in the mines inspected ranged from very wet to very dry. The Heath Steele Mine certainly provided an example of severe leakage through either the country rock, the ore, or both. By way of contrast, the Brunswick Mine is very dry, particularly at the 2800 foot level. A note of caution is raised by this dissimilarity, inasmuch as the local geologic setting for both mines is very much alike. The Buchans Mine also provided evidence of dry conditions at the depth inspected (3215 ft). The Ming Mine at Baie Verte is also nearly dry with a decrease in water leakage with depth. It seems reasonable to tentatively conclude that mined openings in the rock types investigated (volcanics and sediments metamorphosed to a low or subgreen schist facies and intensely deformed) would provide hydraulic isolation at depths on the order of 2800-3200 feet below the surface or greater. It is disturbing to have found one mine that is very wet at shallow depths and to have received reports of some water problems in shaft construction. This report in conjunction with other more comprehensive studies should provide a point of departure for more detailed studies of the nature and causes of hydraulic isolation provided by igneous and metamorphic rocks. 27 figs

  20. Regional Tectonic Control of Tertiary Mineralization and Recent Faulting in the Southern Basin-Range Province, an Application of ERTS-1 Data

    Science.gov (United States)

    Bechtold, I. C.; Liggett, M. A.; Childs, J. F.

    1973-01-01

    Research based on ERTS-1 MSS imagery and field work in the southern Basin-Range Province of California, Nevada and Arizona has shown regional tectonic control of volcanism, plutonism, mineralization and faulting. This paper covers an area centered on the Colorado River between 34 15' N and 36 45' N. During the mid-Tertiary, the area was the site of plutonism and genetically related volcanism fed by fissure systems now exposed as dike swarms. Dikes, elongate plutons, and coeval normal faults trend generally northward and are believed to have resulted from east-west crustal extension. In the extensional province, gold silver mineralization is closely related to Tertiary igneous activity. Similarities in ore, structural setting, and rock types define a metallogenic district of high potential for exploration. The ERTS imagery also provides a basis for regional inventory of small faults which cut alluvium. This capability for efficient regional surveys of Recent faulting should be considered in land use planning, geologic hazards study, civil engineering and hydrology.

  1. Characteristics and mode of emplacement of gneiss domes and plutonic domes in central-eastern Pyrenees

    Science.gov (United States)

    Soula, Jean-Claude

    Gneiss domes and plutonic granitoid domes make up almost 50% of the pre-Hercynian terrains in the Central and Eastern Pyrenees. From a structural study of the shape and internal structure of the domes and of their relationships with the enclosing rocks, it can be shown that both types of domes were emplaced diapirically during the major regional deformation phase and the peak of regional metamorphism. The study also shows that the internal structure, the overall shape and general behaviour relative to the host rocks are similar for plutonic domes and for gneiss domes. This appears to be in good agreement with H. Ramberg's (1967, Gravity Deformation and the Earth's Crust. Academic Press, London; 1970, Model studies in relation to intrusion of plutonic bodies. In: Mechanisms of Igneous Intrusion (edited by Newall, G. & Rast, N.) Geol. J. Spec. Issue2, 261-286.) model studies showing that dome or mushroom-like structures, similar to those observed, develop when there is a small viscosity ratio between the rising body and its enclosing medium. This implies a high crystal content for the granitoid magma. This crystal content has been estimated by (i) calculating the viscosity and density in natural conditions from petrological data for the magma considered as a suspension, using the model and program of J. P. Carron et al. (1978 Bull Soc. géol. Fr.20, 739-744.); (ii) using the recent results of experimental deformation of partially melted granites of I. van der Molen & M. S. Paterson (1979, Contr. Miner. Petrol.70, 299-318.) and (ii) comparing the preceding results with the data obtained by deformation experiments on rocks similar to those enclosing the domes. The minimum crystal content for the development of a dome-like structure has been, thus, estimated to about 70%, i.e. a value very close to that estimated by van der Molen & Paterson (1979) to be the critical value separating the granular framework flow from suspension-like behaviour. The effect of small

  2. Uncertainty and sensitivity results for pre-waste-emplacement groundwater travel time

    International Nuclear Information System (INIS)

    Kaplan, P.G.

    1992-01-01

    In this paper uncertainty and sensitivity analyses for pre-waste-emplacement groundwater travel time conducted. Although preliminary, a numbed of interesting results were obtained. Uncertainty in the ground water travel time statistics, as measured by the coefficient of variation, increases and then decrease as the modeled system transitions from matrix-dominated to fracture-dominated flow. The uncertainty analysis also suggests that the median, as opposed to the mean, may be a better indicator of performance with respect to the regulatory criterion. The sensitivity analysis shows a strong correlation between an effective fracture property, fracture porosity, and failure to meet the regulatory pre-waste-emplacement groundwater travel time criterion of 1,000 years

  3. Waste Handling and Emplacement Options for Disposal of Radioactive Waste in Deep Boreholes

    International Nuclear Information System (INIS)

    Cochran, John R.; Hardin, Ernest

    2015-01-01

    Traditional methods cannot be used to handle and emplace radioactive wastes in boreholes up to 16,400 feet (5 km) deep for disposal. This paper describes three systems that can be used for handling and emplacing waste packages in deep borehole: (1) a 2011 reference design that is based on a previous study by Woodward-Clyde in 1983 in which waste packages are assembled into ''strings'' and lowered using drill pipe; (2) an updated version of the 2011 reference design; and (3) a new concept in which individual waste packages would be lowered to depth using a wireline. Emplacement on coiled tubing was also considered, but not developed in detail. The systems described here are currently designed for U.S. Department of Energy-owned high-level waste (HLW) including the Cesium- 137/Strontium-90 capsules from the Hanford Facility and bulk granular HLW from fuel processing in Idaho.

  4. Improvements relating to apparatus for emplacing or replacing a gaiter

    International Nuclear Information System (INIS)

    Chilvers, D.; Morrison, D.M.

    1982-01-01

    The invention relates to apparatus for emplacing or replacing a gaiter of the type which may be used in sealing the hot side of an isolation enclosure which is associated with a master-slave manipulator. (author)

  5. Architecture and emplacement of flood basalt flow fields: case studies from the Columbia River Basalt Group, NW USA

    Science.gov (United States)

    Vye-Brown, C.; Self, S.; Barry, T. L.

    2013-03-01

    The physical features and morphologies of collections of lava bodies emplaced during single eruptions (known as flow fields) can be used to understand flood basalt emplacement mechanisms. Characteristics and internal features of lava lobes and whole flow field morphologies result from the forward propagation, radial spread, and cooling of individual lobes and are used as a tool to understand the architecture of extensive flood basalt lavas. The features of three flood basalt flow fields from the Columbia River Basalt Group are presented, including the Palouse Falls flow field, a small (8,890 km2, ˜190 km3) unit by common flood basalt proportions, and visualized in three dimensions. The architecture of the Palouse Falls flow field is compared to the complex Ginkgo and more extensive Sand Hollow flow fields to investigate the degree to which simple emplacement models represent the style, as well as the spatial and temporal developments, of flow fields. Evidence from each flow field supports emplacement by inflation as the predominant mechanism producing thick lobes. Inflation enables existing lobes to transmit lava to form new lobes, thus extending the advance and spread of lava flow fields. Minimum emplacement timescales calculated for each flow field are 19.3 years for Palouse Falls, 8.3 years for Ginkgo, and 16.9 years for Sand Hollow. Simple flow fields can be traced from vent to distal areas and an emplacement sequence visualized, but those with multiple-layered lobes present a degree of complexity that make lava pathways and emplacement sequences more difficult to identify.

  6. Sevatian and Norian/Rhaetian boundary: time of environmental, climatic and biotic changes

    Science.gov (United States)

    Rigo, M.; Onoue, T.

    2017-12-01

    Late Triassic is a period characterized by complex and extreme environmental, climatic and biotic changes, such as the break-up of the supercontinent Pangaea; the End-Triassic mass extinction; the emplacement of the Wrangellia and CAMP volcanisms. In particular, uppermost Norian (Sevatian) and Rhaetian seem to record significant δ13Corg excursions associated with an intense warming episodes (δ18O = 1.7‰, Trotter et al., 2015: EPSL, 415, 165-174) and important episodes of faunal turnovers. Three rapid oscillations of δ13Corg have been recognized in the Lagonegro Basin (southern Italy) during Sevatian (Zaffani et al., 2017), paired with a severe conodont turnover towards cavitate forms that are typical of stressing period. The obtained δ13Corg profiles show negative shifts correlatable with those of the North American record, suggesting a widespread occurrence. The last isotopic oscillation is characterized by a negative shift close to the first appearance of the conodont Misikella posthernsteini (=Norian/Rhaetian boundary), culminating with a positive δ13Corg excursion that corresponds to the extinction of the bivalve Monotis (Ward et al., 2004: EPSL, 224, 589-600). This δ13Corg perturbation is also associated with 87Sr/86Sr negative shift (Rigo et al., 2016: Lethaia, 49, 287- 306), indicating a possibly emplacement of a Large Igneous Province (LIP). This Norian magmatic activity may be ascribed to the Angayucham province (Alaska, North America) (Zaffani et al., 2017: Geosphere, 13/4, 1-16), an oceanic plateau active ca. 214±7 Ma, with an estimated volume of ca. 0.5-1x106 km3 (Prokoph et al., 2013: Geoscience Frontiers, 4, 263-276).

  7. The giant Upper Yangtze Pb-Zn province in SW China: Reviews, new advances and a new genetic model

    Science.gov (United States)

    Zhou, Jia-Xi; Xiang, Zhen-Zhong; Zhou, Mei-Fu; Feng, Yue-Xing; Luo, Kai; Huang, Zhi-Long; Wu, Tao

    2018-04-01

    In the western margin of the Yangtze Block, SW China, the Emeishan large igneous province (ELIP) is spatially associated with >400 carbonate-hosted epigenetic Pb-Zn deposits. These deposits form the giant Upper Yangtze Pb-Zn metallogenic province with >20 Mt base metals. In the southeastern part of this province, the important Pb-Zn deposits include those of the Yinchangpo, Yunluhe, Maozhachang, Tianqiao, Banbanqiao, Mangdong, Shaojiwan, Liangyan, Qingshan, Shanshulin, Nayongzhi and Guanziyao deposits. Sulfide ore bodies in these deposits are (i) hosted in late Ediacaran to middle Permian limestone, dolomitic limestone and dolostone; (ii) structurally controlled by reverse fault-anticline tectonic systems; and (iii) spatially associated with the ELIP flood basalts and mafic dikes, and early Permian, early Carboniferous and early Cambrian organic matter-rich black shales. C-O isotopic compositions suggest that dolostone and limestone, mantle-derived rocks of the ELIP, and sedimentary organic matters supplied C-O to the hydrothermal systems through water/rock (W/R) interaction. New and existing S isotopic compositions of sulfides imply multiple sources of S and the reduction of sulfate through both abiotic thermochemical (TSR) and bacterially mediated (BSR) processes. Zn isotopes indicate that the sources of Zn were most likely related to the ELIP with various contributions from sediments and basements locally. Pb isotope signatures are suggestive of derivation of Pb from basements and sedimentary rocks with variable influences from the ELIP. Sr isotopes support that mantle-derived rocks, sediments and basements were involved in Pb-Zn mineralization, and they have various contributions in different deposits. We consider that the Pb-Zn deposits in the Upper Yangtze province are the mixed products of multiple S species-bearing solutions and metal-rich fluids, both of which were derived from, flowed through or interacted with multiple lithostratigraphic units in the

  8. From initiation to termination: a petrostratigraphic tour of the Ethiopian Low-Ti Flood Basalt Province

    Science.gov (United States)

    Krans, S. R.; Rooney, T. O.; Kappelman, J.; Yirgu, G.; Ayalew, D.

    2018-05-01

    Continental flood basalts (CFBs), thought to preserve the magmatic record of an impinging mantle plume head, offer spatial and temporal insights into melt generation processes in large igneous provinces (LIPs). Despite the utility of CFBs in probing mantle plume composition, these basalts typically erupt fractionated compositions, suggestive of significant residence time in the continental lithosphere. The location and duration of residence within the lithosphere provide additional insights into the flux of plume-related magmas. The NW Ethiopian plateau offers a well-preserved stratigraphic sequence from flood basalt initiation to termination, and is thus an important target for study of CFBs. This study examines modal observations within a stratigraphic framework and places these observations within the context of the magmatic evolution of the Ethiopian CFB province. Data demonstrate multiple pulses of magma recharge punctuated by brief shut-down events, with initial flows fed by magmas that experienced deeper fractionation (lower crust). Broad changes in modal mineralogy and flow cyclicity are consistent with fluctuating changes in magmatic flux through a complex plumbing system, indicating pulsed magma flux and an overall shallowing of the magmatic plumbing system over time. The composition of plagioclase megacrysts suggests a constant replenishing of new primitive magma recharging the shallow plumbing system during the main phase of volcanism, reaching an apex prior to flood basalt termination. The petrostratigraphic data sets presented in this paper provide new insight into the evolution of a magma plumbing system in a CFB province.

  9. Geochemical and modal data for igneous rocks associated with epithermal mineral deposits

    Science.gov (United States)

    du Bray, Edward A.

    2014-01-01

    The purposes of this report are to (1) present available geochemical and modal data for igneous rocks associated with epithermal mineral deposits and (2) to make those data widely and readily available for subsequent, more in-depth consideration and interpretation. Epithermal precious and base-metal deposits are commonly associated with subduction-related calc-alkaline to alkaline arc magmatism as well as back-arc continental rift magmatism. These deposits form in association with compositionally diverse extrusive and intrusive igneous rocks. Temperature and depth regimes prevailing during deposit formation are highly variable. The deposits form from hydrothermal fluids that range from acidic to near-neutral pH, and they occur in a variety of structural settings. The disparate temperature, pressure, fluid chemistry, and structural controls have resulted in deposits with wide ranging characteristics. Economic geologists have employed these characteristics to develop classification schemes for epithermal deposits and to constrain the important genetic processes responsible for their formation.

  10. Reassessment of petrogenesis of Carboniferous–Early Permian rift-related volcanic rocks in the Chinese Tianshan and its neighboring areas

    Directory of Open Access Journals (Sweden)

    Linqi Xia

    2012-07-01

    Full Text Available The Carboniferous−Early Permian rift-related volcanic successions, covering large areas in the Chinese Tianshan and its adjacent areas, make up a newly recognized important Phanerozoic large igneous province in the world, which can be further divided into two sub-provinces: Tianshan and Tarim. The regional unconformity of Lower Carboniferous upon basement or pre-Carboniferous rocks, the ages (360–351 Ma of the youngest ophiolite and the peak of subduction metamorphism of high pressure–low temperature metamorphic belt and the occurrence of Ni-Cu-bearing mafic-ultramafic intrusion with age of ∼352 Ma and A-type granite with age of ∼358 Ma reveal that the final closure of the Paleo-Asian Ocean might take place in the Early Mississippian. Our summation shows that at least four criteria, being normally used to identify ancient asthenosphere upwelling (or mantle plumes, are met for this large igneous province: (1 surface uplift prior to magmatism; (2 being associated with continental rifting and breakup events; (3 chemical characteristics of asthenosphere (or plume derived basalts; (4 close links to large-scale mineralization and the uncontaminated basalts, being analogous to those of many “ore-bearing” large igneous provinces, display Sr-Nd isotopic variations between plume and EM1 geochemical signatures. These suggest that a Carboniferous asthenosphere upwelling and an Early Permian plume played the central role in the generation of the Tianshan–Tarim (central Asia large igneous province.

  11. Wireless Sensor Networks for Detection of IED Emplacement

    Science.gov (United States)

    2009-06-01

    unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Abstract We are investigating the use of wireless nonimaging -sensor...networks for the difficult problem of detection of suspicious behavior related to IED emplacement. Hardware for surveillance by nonimaging -sensor networks...with people crossing a live sensor network. We conclude that nonimaging -sensor networks can detect a variety of suspicious behavior, but

  12. Statistical analysis of the sustained lava dome emplacement and destruction processes at Popocatépetl volcano, Central México

    Science.gov (United States)

    Mendoza-Rosas, Ana Teresa; Gómez-Vázquez, Ángel; De la Cruz-Reyna, Servando

    2017-06-01

    Popocatépetl volcano reawakened in 1994 after nearly 70 years of quiescence. Between 1996 and 2015, a succession of at least 38 lava domes have been irregularly emplaced and destroyed, with each dome reaching particular volumes at specific emplacement rates. The complexity of this sequence is analyzed using statistical methods in an attempt to gain insight into the physics and dynamics of the lava dome emplacement and destruction process and to objectively assess the hazards related to that volcano. The time series of emplacements, dome residences, lava effusion lulls, and emplaced dome volumes and thicknesses are modeled using the simple exponential and Weibull distributions, the compound non-homogeneous generalized Pareto-Poisson process (NHPPP), and the mixture of exponentials distribution (MOED). The statistical analysis reveals that the sequence of dome emplacements is a non-stationary, self-regulating process most likely controlled by the balance between buoyancy-driven magma ascent and volatile exsolution crystallization. This balance has supported the sustained effusive activity for decades and may persist for an undetermined amount of time. However, the eruptive history of Popocatépetl includes major Plinian phases that may have resulted from a breach in that balance. Certain criteria to recognize such breaching conditions are inferred from this statistical analysis.

  13. From an ocean floor wrench zone origin to transpressional tectonic emplacement of the Sithonia ophiolite, eastern Vardar Suture Zone, northern Greece

    Science.gov (United States)

    Bonev, Nikolay; Filipov, Petyo

    2017-12-01

    In the Hellenides of northern Greece, the Sithonia back-arc ophiolite constitute an element of the Vardar suture zone against the Chortiatis island arc magmatic suite, the Melissochori Formation and the Serbo-Macedonian Massif further north at the Mesozoic continental margin of Eurasia. A granodiorite from the Chortiatis island arc magmatic suite crystallized at 160 Ma as derived from new U-Pb zircon geochronology and confirms the end of arc magmatic activity that started at around 173 Ma. Located southerly of the Chortiatis island arc magmatic suite, the Sithonia ophiolite had igneous life from 159 to 149 Ma, and the ophiolite interfinger with clastic-carbonate Kimmeridgian sediments. Magmatic structures (i.e., sheeted dykes) in the ophiolite witness for NE-trending rift axis, while the transform faults and fracture zones sketch NW-SE transcurrent transtension-like propagation of the rift-spreading center at Sithonia that is consistent with a dextral wrench corridor already proposed for the ophiolite origin in the eastern Vardar zone. The tectonic emplacement of the Sithonia ophiolite involved dextral ENE to SE strike-slip sense of shear and SW and NE reverse thrust sense of shear on mostly steep foliation S1, subhorizontal lineation L1 and associated variably inclined F1 fold axes. This structural grain and kinematics are shared by adjacent Chortiatis island arc magmatic suite and the Melissochori Formation. The coexistence of strike-parallel and thrust components of displacement along discrete dextral strike-slip shear zones and internal deformation of the mentioned units is interpreted to result from a bulk dextral transpressive deformation regime developed in greenschist-facies metamorphic conditions. The back-arc ocean floor previous structural architecture with faults and fracture zones where Kimmeridgian sediments deposited in troughs was used by discrete strike-slip shear zones in which these sediments involved, and the shear zones become the sites for

  14. Radioactive occurrences in veins and igneous and metamorphic rocks of New Mexico with annotated bibliography

    International Nuclear Information System (INIS)

    McLemore, V.T.

    1982-01-01

    From an extensive literature search and field examination of 96 nonsandstone radioactive occurrences, the author compiled an annotated bibliography of over 600 citations and a list of 327 radioactive occurrences in veins and igneous and metamorphic rocks of New Mexico. The citations are indexed by individual radioactive occurrence, geographic area, county, fluorspar deposits and occurrences, geochemical analyses, and geologic maps. In addition, the geology, mineralization, and uranium and thorium potential of 41 geographic areas in New Mexico containing known radioactive occurrences in veins and igneous and metamorphic rocks or that contain host rocks considered favorable for uranium or thorium mineralization are summarized. A list of aerial-radiometric, magnetic, hydrogeochemical, and stream-sediment survey reports is included

  15. Radioactive occurrences in veins and igneous and metamorphic rocks of New Mexico with annotated bibliography

    International Nuclear Information System (INIS)

    McLemore, V.T.

    1982-02-01

    The primary objectives of this report are to list known radioactive occurrences in veins and igneous and metamorphic rocks in New Mexico, and to provide an annotated bibliography of geologic reports concerning these regions. Only plutonic, metamorphic, vein, and Precambrian quartz-pebble conglomerate uranium deposits are considered in this report; other nonsandstone uranium deposits (such as shale, limestone, phosphorite, coal, evaporative precipitates, and fossil placer deposits) will be considered at a later time. These objectives were achieved through a literature search. Some field examinations of some of the radioactive occurrences have been completed. A table of known radioactive occurrences in veins and igneous and metamorphic rocks was compiled from the literature (Appendix I)

  16. Buffered and unbuffered dike emplacement on Earth and Venus - Implications for magma reservoir size, depth, and rate of magma replenishment

    Science.gov (United States)

    Parfitt, E. A.; Head, J. W., III

    1993-01-01

    Models of the emplacement of lateral dikes from magma chambers under constant (buffered) driving pressure conditions and declining (unbuffered) driving pressure conditions indicate that the two pressure scenarios lead to distinctly different styles of dike emplacement. In the unbuffered case, the lengths and widths of laterally emplaced dikes will be severely limited and the dike lengths will be highly dependent on chamber size; this dependence suggests that average dike length can be used to infer the dimensions of the source magma reservoir. On Earth, the characteristics of many mafic-dike swarms suggest that they were emplaced in buffered conditions (e.g., the Mackenzie dike swarm in Canada and some dikes within the Scottish Tertiary). On Venus, the distinctive radial fractures and graben surrounding circular to oval features and edifices on many size scales and extending for hundreds to over a thousand km are candidates for dike emplacement in buffered conditions.

  17. Logistics Modeling of Emplacement Rate and Duration of Operations for Generic Geologic Repository Concepts

    Energy Technology Data Exchange (ETDEWEB)

    Kalinina, Elena Arkadievna; Hardin, Ernest

    2015-11-01

    This study identified potential geologic repository concepts for disposal of spent nuclear fuel (SNF) and (2) evaluated the achievable repository waste emplacement rate and the time required to complete the disposal for these concepts. Total repository capacity is assumed to be approximately 140,000 MT of spent fuel. The results of this study provide an important input for the rough-order-of-magnitude (ROM) disposal cost analysis. The disposal concepts cover three major categories of host geologic media: crystalline or hard rock, salt, and argillaceous rock. Four waste package sizes are considered: 4PWR/9BWR; 12PWR/21BWR; 21PWR/44BWR, and dual purpose canisters (DPCs). The DPC concepts assume that the existing canisters will be sealed into disposal overpacks for direct disposal. Each concept assumes one of the following emplacement power limits for either emplacement or repository closure: 1.7 kW; 2.2 kW; 5.5 kW; 10 kW; 11.5 kW, and 18 kW.

  18. Logistics Modeling of Emplacement Rate and Duration of Operations for Generic Geologic Repository Concepts

    International Nuclear Information System (INIS)

    Kalinina, Elena Arkadievna; Hardin, Ernest

    2015-01-01

    This study identified potential geologic repository concepts for disposal of spent nuclear fuel (SNF) and (2) evaluated the achievable repository waste emplacement rate and the time required to complete the disposal for these concepts. Total repository capacity is assumed to be approximately 140,000 MT of spent fuel. The results of this study provide an important input for the rough-order-of-magnitude (ROM) disposal cost analysis. The disposal concepts cover three major categories of host geologic media: crystalline or hard rock, salt, and argillaceous rock. Four waste package sizes are considered: 4PWR/9BWR; 12PWR/21BWR; 21PWR/44BWR, and dual purpose canisters (DPCs). The DPC concepts assume that the existing canisters will be sealed into disposal overpacks for direct disposal. Each concept assumes one of the following emplacement power limits for either emplacement or repository closure: 1.7 kW; 2.2 kW; 5.5 kW; 10 kW; 11.5 kW, and 18 kW.

  19. STRUCTURAL CALCULATION OF AN EMPLACEMENT PALLET STATICALLY LOADED BY A WASTE PACKAGE

    International Nuclear Information System (INIS)

    S. Mastilovic

    2000-01-01

    The purpose of this calculation is to determine the structural response of the emplacement pallet (EP) subjected to static load from the mounted waste package (WP). The scope of this document is limited to reporting the calculation results in terms of stress intensity magnitudes. This calculation is associated with the waste emplacement systems design; calculations are performed by the Waste Package Design group. AP-3.12Q, Revision 0, ICN 0, Calculations, is used to perform the calculation and develop the document. The finite element solutions are performed by using the commercially available ANSYS Version (V) 5.4 finite element code. The results of these calculations are provided in terms of maximum stress intensity magnitudes

  20. Petrogenesis of early cretaceous silicic volcanism in SE Uruguay. The role of mantle and crustal sources

    International Nuclear Information System (INIS)

    Lustrino, Michele; Morbidelli, Lucio; Marrazzo, Marianna; Melluso, Leone; Brotzu, Pietro; Tassinari, Colombo C.G.; Gomes, Celso B.; Ruberti, Excelso

    2010-01-01

    Early Cretaceous (∼129 Ma) silicic rocks crop out in SE Uruguay between the Laguna Merin and Santa Lucia basins in the Lascano, Sierra Sao Miguel, Salamanca and Minas areas. They are mostly rhyolites with minor quartz-trachytes and are nearly contemporaneous with the Parana-Etendeka igneous province and with the first stages of South Atlantic Ocean opening. A strong geochemical variability (particularly evident from Rb/Nb, Nb/Y trace element ratios) and a wide range of Sr-Nd isotopic ratios ( 143 Nd/ 144 Nd (129) =0.51178-0.51209; 87 Sr/ 86 Sr (129) =0.70840-0.72417) characterize these rocks. Geochemistry allows to distinguish two compositional groups, corresponding to the north-eastern (Lascano and Sierra Sao Miguel, emplaced on the Neo-Proterozoic southern sector of the Dom Feliciano mobile belt) and south-eastern localities (Salamanca, Minas, emplaced on the much older (Archean) Nico Perez terrane or on the boundary between the Dom Feliciano and Nico Perez terranes). These compositional differences between the two groups are explained by variable mantle source and crust contributions. The origin of the silicic magmas is best explained by complex processes involving assimilation and fractional crystallization and mixing of a basaltic magma with upper crustal lithologies, for Lascano and Sierra Sao Miguel rhyolites. In the Salamanca and Minas rocks genesis, a stronger contribution from lower crust is indicated. (author)

  1. Osmium isotope variations accompanying the eruption of a single lava flow field in the Columbia River Flood Basalt Province

    Science.gov (United States)

    Vye-Brown, C.; Gannoun, A.; Barry, T. L.; Self, S.; Burton, K. W.

    2013-04-01

    Geochemical interpretations of continental flood basalts usually assume that individual lava flows represent compositionally homogenous and rapidly erupted products of large well-mixed magma reservoirs. However, inflated pāhoehoe lavas may develop over considerable periods of time and preserve chemical variations that can be temporally linked through flow formation to eruption sequence thus providing an understanding of magma evolution over the timescale of a single eruption. This study presents comprehensive major, trace element and Re-Os isotope data for a single eruption that formed the 2660 km3 Sand Hollow flow field in the Columbia River Basalt Province, USA. Major and trace element variations accompanying flow emplacement (e.g. MgO 3.09-4.55 wt%, Ni 17.5-25.6 ppm) are consistent with fractional crystallisation, but other petrogenetic processes or variable sources cannot be distinguished. However, there is a systematic shift in the initial 187Os/188Os isotope composition of the magma (age corrected to 15.27 Ma), from 0.174 (lava core) to 1.444 (lava crust) within a single 35 m thick sheet lobe. Lava crust values are more radiogenic than any known mantle source, consistent with previous data indicating that neither an enriched reservoir nor the sub-continental lithospheric mantle are likely to have sourced these basalts. Rather, these data indicate that lavas emplaced during the earliest stages of eruption have higher degrees of crustal contamination. These results highlight the limitations of applying chemostratigraphic correlation across continental flood basalt provinces, the use of single data points to define melt sources and magmatic processes, and the dangers of using conventional isochron techniques in such basalt sequences for absolute chronology.

  2. Study on a transportation and emplacement system of pre-assembled EBS module for HLW geological disposal

    International Nuclear Information System (INIS)

    Awano, Toshihiko; Kanno, Takeshi; Katsumata, Syunsuke; Kosuge, Kazuhiro

    2009-01-01

    HLW disposal is one of the largest issue to utilize Nuclear power safely. In the past study, the concept, which buffer materials and Overpacked waste were transported into underground respectively, have shown. The concept of pre-assembled engineered barrier has advantage to simplify the logistics and emplacement procedure, however there are difficulties to support heavy weight of pre-assembled package by equipment under the condition of little clearance between tunnel and package. In this study, Combination of air bearing and two degree-of-freedom wheels were suggested for transportation, and air jack was suggested for unloading and emplacement system. Also, whole system for transportation and emplacement procedure was designed, and Scale model test was examined to evaluate the feasibility of these concept and functions. (author)

  3. Regional framework and geology of iron oxide-apatite-rare earth element and iron oxide-copper-gold deposits of the Mesoproterozoic St. Francois Mountains Terrane, southeast Missouri

    Science.gov (United States)

    Day, Warren C.; Slack, John F.; Ayuso, Robert A.; Seeger, Cheryl M.

    2016-01-01

    This paper provides an overview on the genesis of Mesoproterozoic igneous rocks and associated iron oxide ± apatite (IOA) ± rare earth element, iron oxide-copper-gold (IOCG), and iron-rich sedimentary deposits in the St. Francois Mountains terrane of southeast Missouri, USA. The St. Francois Mountains terrane lies along the southeastern margin of Laurentia as part of the eastern granite-rhyolite province. The province formed during two major pulses of igneous activity: (1) an older early Mesoproterozoic (ca. 1.50–1.44 Ga) episode of volcanism and granite plutonism, and (2) a younger middle Mesoproterozoic (ca. 1.33–1.30 Ga) episode of bimodal gabbro and granite plutonism. The volcanic rocks are predominantly high-silica rhyolite pyroclastic flows, volcanogenic breccias, and associated volcanogenic sediments with lesser amounts of basaltic to andesitic volcanic and associated subvolcanic intrusive rocks. The iron oxide deposits are all hosted in the early Mesoproterozoic volcanic and volcaniclastic sequences. Previous studies have characterized the St. Francois Mountains terrane as a classic, A-type within-plate granitic terrane. However, our new whole-rock geochemical data indicate that the felsic volcanic rocks are effusive derivatives from multicomponent source types, having compositional similarities to A-type within-plate granites as well as to S- and I-type granites generated in an arc setting. In addition, the volcanic-hosted IOA and IOCG deposits occur within bimodal volcanic sequences, some of which have volcanic arc geochemical affinities, suggesting an extensional tectonic setting during volcanism prior to emplacement of the ore-forming systems.The Missouri iron orebodies are magmatic-related hydrothermal deposits that, when considered in aggregate, display a vertical zonation from high-temperature, magmatic ± hydrothermal IOA deposits emplaced at moderate depths (~1–2 km), to magnetite-dominant IOA veins and IOCG deposits emplaced at shallow

  4. Quarter-scale modeling of room convergence effects on CH [contact-handled] TRU drum waste emplacements using WIPP [Waste Isolation Pilot Plant] reference design geometries

    International Nuclear Information System (INIS)

    VandeKraats, J.

    1987-11-01

    This study investigates the effect of horizontal room convergence on CH waste packages emplaced in the WIPP Reference Design geometry (rooms 13 feet high by 33 feet wide, with minus 3/8 inch screened backfill emplaced over and around the waste packages) as a function of time. Based on two tests, predictions were made with regard to full-scale 6-packs emplaced in the Reference Design geometry. These are that load will be transmitted completely through the stack within the first five years after waste emplacement and all drums in all 6-packs will be affected; that virtually all drums will show some deformation eight years after emplacement; that some drums may breach before the eighth year after emplacement has elapsed; and that based on criteria developed during testing, it is predicted that 1% of the drums emplaced will be breached after 8 years and, after 15 years, approximately 12% of the drums are predicted to be breached. 8 refs., 41 figs., 3 tabs

  5. Classification Scheme for Diverse Sedimentary and Igneous Rocks Encountered by MSL in Gale Crater

    Science.gov (United States)

    Schmidt, M. E.; Mangold, N.; Fisk, M.; Forni, O.; McLennan, S.; Ming, D. W.; Sumner, D.; Sautter, V.; Williams, A. J.; Gellert, R.

    2015-01-01

    The Curiosity Rover landed in a lithologically and geochemically diverse region of Mars. We present a recommended rock classification framework based on terrestrial schemes, and adapted for the imaging and analytical capabilities of MSL as well as for rock types distinctive to Mars (e.g., high Fe sediments). After interpreting rock origin from textures, i.e., sedimentary (clastic, bedded), igneous (porphyritic, glassy), or unknown, the overall classification procedure (Fig 1) involves: (1) the characterization of rock type according to grain size and texture; (2) the assignment of geochemical modifiers according to Figs 3 and 4; and if applicable, in depth study of (3) mineralogy and (4) geologic/stratigraphic context. Sedimentary rock types are assigned by measuring grains in the best available resolution image (Table 1) and classifying according to the coarsest resolvable grains as conglomerate/breccia, (coarse, medium, or fine) sandstone, silt-stone, or mudstone. If grains are not resolvable in MAHLI images, grains in the rock are assumed to be silt sized or smaller than surface dust particles. Rocks with low color contrast contrast between grains (e.g., Dismal Lakes, sol 304) are classified according to minimum size of apparent grains from surface roughness or shadows outlining apparent grains. Igneous rocks are described as intrusive or extrusive depending on crystal size and fabric. Igneous textures may be described as granular, porphyritic, phaneritic, aphyric, or glassy depending on crystal size. Further descriptors may include terms such as vesicular or cumulate textures.

  6. Performance implications of waste package emplacement orientation

    International Nuclear Information System (INIS)

    Wilder, D.G.

    1991-05-01

    Emplacement borehole orientation directly impacts many aspects of the Engineered Barrier System (EBS) and interactions with the near field environment. This paper considers the impacts of orientation on the hydrologic portion of the environment and its interactions with the EBS. The hydrologic environment is considered from a conceptual standpoint, the numerical analyses are left for subsequent work. As reported in this paper, several aspects of the hydrological environment are more favorable for long term performance of vertically oriented rather than horizontally oriented Waste Packages. 19 refs., 15 figs

  7. Smectite clay identification and quantification as an indicator of basic igneous rock durability

    CSIR Research Space (South Africa)

    Leyland, RC

    2014-09-01

    Full Text Available In terms of aerial extent, basic igneous rocks are one of the most used road building materials in South Africa. This is mainly due to the fact that approximately 57% of the surface lithology in South Africa is of poor road construction quality...

  8. Hydrothermal reequilibration of igneous magnetite in altered granitic plutons and its implications for magnetite classification schemes: Insights from the Handan-Xingtai iron district, North China Craton

    Science.gov (United States)

    Wen, Guang; Li, Jian-Wei; Hofstra, Albert H.; Koenig, Alan E.; Lowers, Heather A.; Adams, David

    2017-09-01

    Magnetite is a common mineral in igneous rocks and has been used as an important petrogenetic indicator as its compositions and textures reflect changing physiochemical parameters such as temperature, oxygen fugacity and melt compositions. In upper crustal settings, igneous rocks are often altered by hydrothermal fluids such that the original textures and compositions of igneous magnetite may be partly or completely obliterated, posing interpretive problems in petrological and geochemical studies. In this paper, we present textural and compositional data of magnetite from variably albitized granitoid rocks in the Handan-Xingtai district, North China Craton to characterize the hydrothermal reequilibration of igneous magnetite. Four types of magnetite have been identified in the samples studied: pristine igneous magnetite (type 1), reequilibrated porous magnetite (type 2), reequilibrated nonporous magnetite (type 3), and hydrothermal magnetite (type 4). Pristine igneous magnetite contains abundant well-developed ilmenite exsolution lamellae that are largely replaced by titanite during subsequent hydrothermal alteration. The titanite has a larger molar volume than its precursor ilmenite and thus causes micro-fractures in the host magnetite grains, facilitating dissolution and reprecipitation of magnetite. During sodic alteration, the igneous magnetite is extensively replaced by type 2 and type 3 magnetite via fluid-induced dissolution and reprecipitation. Porous type 2 magnetite is the initial replacement product of igneous magnetite and is subsequently replaced by the nonoporous type 3 variety as its surface area is reduced and compositional equilibrium with the altering fluid is achieved. Hydrothermal type 4 magnetite is generally euhedral and lacks exsolution lamellae and porosity, and is interpreted to precipitate directly from the ore-forming fluids. Hydrothermal reequilibration of igneous magnetite has led to progressive chemical purification, during which trace

  9. Temporal record of osmium concentrations and 187Os/188Os in organic-rich mudrocks: Implications for the osmium geochemical cycle and the use of osmium as a paleoceanographic tracer

    Science.gov (United States)

    Lu, Xinze; Kendall, Brian; Stein, Holly J.; Hannah, Judith L.

    2017-11-01

    We present a compilation of 192Os concentrations (representing non-radiogenic Os) and initial 187Os/188Os isotope ratios from organic-rich mudrocks (ORM) to explore the evolution of the Os geochemical cycle during the past three billion years. The initial 187Os/188Os isotope ratio of a Re-Os isochron regression for ORM constrains the local paleo-seawater 187Os/188Os, which is governed by the relative magnitudes of radiogenic Os (old continental crust) and unradiogenic Os (mantle, extraterrestrial, and juvenile/mafic/ultramafic crust) fluxes to seawater. A first-order increase in seawater 187Os/188Os ratios occurs from the Archean to the Phanerozoic, and may reflect a combination of increasing atmosphere-ocean oxygenation and weathering of progressively more radiogenic continental crust due to in-growth of 187Os from radioactive decay of 187Re. Superimposed on this long-term trend are shorter-term fluctuations in seawater 187Os/188Os ratios as a result of climate change, emplacement of large igneous provinces, bolide impacts, tectonic events, changes in seafloor spreading rates, and lithological changes in crustal terranes proximal to sites of ORM deposition. Ediacaran-Phanerozoic ORM have mildly higher 192Os concentrations overall compared with pre-Ediacaran Proterozoic ORM based on the mean and 95% confidence interval of 10,000 median values derived using a bootstrap analysis for each time bin (insufficient Archean data exist for robust statistical comparisons). However, there are two groups with anomalously high 192Os concentrations that are distinguished by their initial 187Os/188Os isotope ratios. Ediacaran-Cambrian ORM from South China have radiogenic initial 187Os/188Os, suggesting their high 192Os concentrations reflect proximal Os-rich crustal source(s), ultraslow sedimentation rates, and/or other unusual depositional conditions. In contrast, the unradiogenic initial 187Os/188Os and high 192Os concentrations of some Mesozoic ORM can be tied to emplacement

  10. Analogue experiments as benchmarks for models of lava flow emplacement

    Science.gov (United States)

    Garel, F.; Kaminski, E. C.; Tait, S.; Limare, A.

    2013-12-01

    During an effusive volcanic eruption, the crisis management is mainly based on the prediction of lava flow advance and its velocity. The spreading of a lava flow, seen as a gravity current, depends on its "effective rheology" and on the effusion rate. Fast-computing models have arisen in the past decade in order to predict in near real time lava flow path and rate of advance. This type of model, crucial to mitigate volcanic hazards and organize potential evacuation, has been mainly compared a posteriori to real cases of emplaced lava flows. The input parameters of such simulations applied to natural eruptions, especially effusion rate and topography, are often not known precisely, and are difficult to evaluate after the eruption. It is therefore not straightforward to identify the causes of discrepancies between model outputs and observed lava emplacement, whereas the comparison of models with controlled laboratory experiments appears easier. The challenge for numerical simulations of lava flow emplacement is to model the simultaneous advance and thermal structure of viscous lava flows. To provide original constraints later to be used in benchmark numerical simulations, we have performed lab-scale experiments investigating the cooling of isoviscous gravity currents. The simplest experimental set-up is as follows: silicone oil, whose viscosity, around 5 Pa.s, varies less than a factor of 2 in the temperature range studied, is injected from a point source onto a horizontal plate and spreads axisymmetrically. The oil is injected hot, and progressively cools down to ambient temperature away from the source. Once the flow is developed, it presents a stationary radial thermal structure whose characteristics depend on the input flow rate. In addition to the experimental observations, we have developed in Garel et al., JGR, 2012 a theoretical model confirming the relationship between supply rate, flow advance and stationary surface thermal structure. We also provide

  11. Effect of repository underground ventilation on emplacement drift temperature control

    International Nuclear Information System (INIS)

    Yang, H.; Sun, Y.; McKenzie, D.G.; Bhattacharyya, K.K.

    1996-01-01

    The repository advanced conceptual design (ACD) is being conducted by the Civilian Radioactive Waste Management System, Management ampersand Operating Contractor. Underground ventilation analyses during ACD have resulted in preliminary ventilation concepts and design methodologies. This paper discusses one of the recent evaluations -- effects of ventilation on emplacement drift temperature management

  12. The full-scale Emplacement (FE) Experiment at the Mont Terri URL

    International Nuclear Information System (INIS)

    Mueller, H.R.; Weber, H.P.; Koehler, S.; Vogt, T.; Vietor, T.

    2012-01-01

    Document available in extended abstract form only. The Full-Scale Emplacement (FE) Experiment at the Mont Terri underground research laboratory (URL) is a full-scale heater test in a clay-rich formation. It simulates the construction, waste emplacement and backfilling of a spent fuel (SF) / vitrified high-level waste (HLW) repository tunnel as realistically as possible. The entire experiment implementation as well as the post-closure THM(C) evolution will be monitored using several hundred sensors. These are distributed in the host rock in the near- and far-field, the tunnel lining, the engineered barrier system and on the heaters. The aim of this experiment is to investigate HLW repository-induced thermo-hydro-mechanical (THM) coupled effects on the host rock and the validation of existing coupled THM models. A further aim is the verification of the technical feasibility of constructing a 50 m repository section at full scale with all relevant components using standard industrial equipment. Finally, the experiment will demonstrate the canister and buffer emplacement procedures for underground conditions based on the Swiss disposal concept. Experimental layout The FE experiment is based on the Swiss disposal concept for SF / HLW. The 50 m long test gallery, at the end of the former MB test tunnel in the Mont Terri URL, will be realised with a diameter of approx. 3 m. In the experiment gallery, 3 heaters with dimensions similar to those of waste canisters will be emplaced on top of abutments built of bentonite blocks. The remaining space will be backfilled with compacted bentonite pellets. The experiment will be sealed off towards the start niche with a concrete plug holding the buffer in place and reducing air and water fluxes. The first scoping calculations and design modelling for the 'far-field' instrumentation have been completed; these works have been carried out using CodeBRIGHT and the multiphase flow simulator TOUGH2. With an initial heat output of 1500 W

  13. The geology of the area south of Vioolsdrif, Cape Province

    International Nuclear Information System (INIS)

    Ward, J.H.W.

    1977-10-01

    Geological reconnaissance of an area of 1 500 square km to the South of Vioolsdrif in northern Namaqualand has revealed that this region straddles the boundary between the upper crustal Richtersveld domain and the subjacent Namaqualand Metamorphic Complex. The Vioolsdrif batholith, which underlies much of the Richtersveld, is a composite body, essentially granodioritic, which was emplaced in a number of epizonal magmatic pulses into an overlying comagmatic canopy of intermediate to felsic lavas and pyroclastics during Bushveld times. It is unlikely that this volcanic carapace exceeded 9 km in thickness. During or following consolidation at about 1 800 Ma, the southern margin of the batholith was affected by a thermotectonic episode of regional extent during which the rocks of the igneous complex were foliated and lineated in sympathy with the dominant tectonic fabric of the contiguous metamorphic complex. Metamorphic mineral parageneses indicate that during the climax of this dynamothermal episode, rocks along the southern margin of the batholith were subjected to temperatures of 620 - 670 degrees and pressures of 0,4 - 0,5 MPa (4 - 5 kbar). During this deformational episode the batholith acted as a tectonic resister which preserved the overlying volcanics from incorporation into the metamorphic complex. More or less coincident with the boundary between the metamorphic complex and the Vioolsdrif batholith is a zone about 10 km in width which is characterised by the development of abundant pegmatites [af

  14. Salt Repository emplacement mode evaluation and selection: Final report

    International Nuclear Information System (INIS)

    1988-03-01

    This document describes the decision analysis performed to evaluate and compare the emplacement mode for the Salt Repository. The study was commissioned to recommend one emplacement mode to the Salt Repository Project Office using multi-attribute decision analysis. The nature of the decision required analysis of uncertain outcomes and conflicting attributes and offers a high degree of objectivity for these types of decisions since the decision model is structured to allow only the facts to enter into the final decision. The analysis requires an explicit definition of the attributes used to evaluate the alternative (e.g., cost, safety, environmental impact), the definition of a utility function over the attributes which incorporated both risk attitudes and trade-offs between attributes, and the probability distribution over the outcomes that would result from the selection of one alternative over the other. The decision process is described and results are given. A simulation model was developed to evaluate the probability distributions over the attributes. This report documents logic, inputs and results of this model. Final ranking of alternatives is given. Extensive technical backup documentation is included in the appendices to provide the quantitative basis for this decision. 5 refs., 2 figs., 8 tabs

  15. Lithology and temperature: How key mantle variables control rift volcanism

    Science.gov (United States)

    Shorttle, O.; Hoggard, M.; Matthews, S.; Maclennan, J.

    2015-12-01

    Continental rifting is often associated with extensive magmatic activity, emplacing millions of cubic kilometres of basalt and triggering environmental change. The lasting geological record of this volcanic catastrophism are the large igneous provinces found at the margins of many continents and abrupt extinctions in the fossil record, most strikingly that found at the Permo-Triassic boundary. Rather than being considered purely a passive plate tectonic phenomenon, these episodes are frequently explained by the involvement of mantle plumes, upwellings of mantle rock made buoyant by their high temperatures. However, there has been debate over the relative role of the mantle's temperature and composition in generating the large volumes of magma involved in rift and intra-plate volcanism, and even when the mantle is inferred to be hot, this has been variously attributed to mantle plumes or continental insulation effects. To help resolve these uncertainties we have combined geochemical, geophysical and modelling results in a two stage approach: Firstly, we have investigated how mantle composition and temperature contribute to melting beneath Iceland, the present day manifestation of the mantle plume implicated in the 54Ma break up of the North Atlantic. By considering both the igneous crustal production on Iceland and the chemistry of its basalts we have been able to place stringent constraints on the viable temperature and lithology of the Icelandic mantle. Although a >100°C excess temperature is required to generate Iceland's thick igneous crust, geochemistry also indicates that pyroxenite comprises 10% of its source. Therefore, the dynamics of rifting on Iceland are modulated both by thermal and compositional mantle anomalies. Secondly, we have performed a global assessment of the mantle's post break-up thermal history to determine the amplitude and longevity of continental insulation in driving excess volcanism. Using seismically constrained igneous crustal

  16. Petrología y Estructura del Complejo Ígneo-Metamórfico Aluminé, Provincia de Neuquén, Argentina Petrology and Structure of the Aluminé Igneous-Metamorphic Complex, Neuquén province, Argentina

    Directory of Open Access Journals (Sweden)

    Ivana A Urraza

    2011-01-01

    andinas (cretácicas o más modernas y el sector sur donde dominan los granitoides preandinos de edades permotriásicas-jurásicas, emplazados en un basamento paleozoico. Si bien los diagramas geoquímicos permiten diferenciar los diferentes petrotipos definidos petrográficamente y sus tendencias evolutivas podrían indicar procesos de cristalización fraccionada, la distribución areal de los mismos, sus características petrográfico-microestructurales y la geocronología, indican que podrían corresponder a diferentes pulsos-eventos magmáticos separados en el tiempo, aunque desarrollados en un contexto de características tectónicas similares.In the present contribution, the partial results of a detailed study of the magmatic, metamorphic and tectonic events developed in the Aluminé Igneous-Metamorphic Complex (AIMC are given. We define the AIMC as the set of pre-andean and andean intrusive igneous and metamorphic rocks, outcropping in the área located between the Aluminé, Moquehue, Ñorquinco and Pulmarí lakes in the Neuquén province, Argentina. Based on field and petrographic observations and geochemical characteristics, the granitic rocks forming part of the AIMC have been classified as: 1. quartz diorites, 2. tonalites-granodiorites, 3. granodiorites and 4. granites. The geochemical parameters indícate that the defined lithologies derive from calcic to weakly calcalkaline magmas of metaluminous composition, typical of Type I Cordilleran batholiths associated with active continental margins. Intercalated between the magmatic rocks, some outcrops of metamorphic basement composed mainly of schists, gneisses, amphibolites and scarce quartzose sandstones. Andesites, tuffs and basalts cover in part the metamorphites and granitoids are exposed. The structure of the sector is characterized by the presence of three main sets of regional lineaments, with NE-SW, NW-SE and N-S orientations. These directions coincide with the orientations of the three groups of

  17. Retrieval system for emplaced spent unreprocessed fuel (SURF) in salt bed depository. Baseline concept criteria specifications and mechanical failure probabilities

    International Nuclear Information System (INIS)

    Hudson, E.E.; McCleery, J.E.

    1979-05-01

    One of the integral elements of the Nuclear Waste Management Program is the material handling task of retrieving Canisters containing spent unreprocessed fuel from their emplacement in a deep geologic salt bed Depository. A study of the retrieval concept data base predicated this report. In this report, alternative concepts for the tasks are illustrated and critiqued, a baseline concept in scenario form is derived and basic retrieval subsystem specifications are presented with cyclic failure probabilities predicted. The report is based on the following assumptions: (a) during retrieval, a temporary radiation seal is placed over each Canister emplacement; (b) a sleeve, surrounding the Canister, was initially installed during the original emplacement; (c) the emplacement room's physical and environmental conditions established in this report are maintained while the task is performed

  18. Association of igneous phophate and uranium

    International Nuclear Information System (INIS)

    Loureiro, F.E.V.L.

    1980-10-01

    Data from Catalao permit some brief comments about the association of igneous phosphate and uranium, and on the possible economic importance of this type of mineralization in spite of the low grades of metals observed. Chemical and mineralogical analyses of carbonatites, phosphate ore and different phosphate concentrates, reveal the existence of important low-grade reserves of Th, Nb, Zr, U and La, and possibly of other metals such as V and Cu. Uranium is enriched 1.6 and 1.2 times, respectively, in the residual muds and flotation wastes produced at the processing plant of Goiasfertil operating in the area. The uranium is associated with two types of minerals, the first one comprised primarily of phosphates of the gorceixite group and secondarily of apatite and dahllite. THe second association is with pyrochlore, or rather barium-pyrochlore. Further investigations of similar occurences may define more clearly and specifically the various factors controlling the observed enrichment in heavy elements. (Author) [pt

  19. Semi-quantitative spectrographic determination of traces of elements in igneous rocks

    International Nuclear Information System (INIS)

    Costa, M.Q. da; Eichhoff, H.-J.

    1982-01-01

    A semi-quantitative spectrographic technique based on Harveys'method, using background radiation as internal standard is described for the analysis of trace elements in igneous rocks by the total energy method. A certain amount of the sample was completely vapourized in a DC arc with anodic excitation under argon and oxygen atmosphere, using graphite electrodes of standard dimensions. In the processed film, selected lines and adjancent backgrounds were evaluated by densitometry and the corresponding intensity ratios were calculated. Sensitivity factors were determined for the analytical lines of Co, Cu, Ga, Ni, Sc, Sr, V, Y, Zn, and Zr in geological standards (G-2, BCR-1, AGV-1, GSP-1) from the United States Geological Survey. Matrix effects between samples and standards were minimized by using the above mentioned geological standards. An average value of the sensitivity factors was employed for the calculation of the concentration of the elements in the samples. A comparison between the results obtained by this method and those from the analysis of zinc by atomic absorption is presented. This method enabled the analyses of igneous rock samples having SiO2 contents between 40 and 80%, with an error in the determinations of trace elements less than 30%.(Author) [pt

  20. New kind of radioactive inclusions in igneous rocks

    Energy Technology Data Exchange (ETDEWEB)

    Coppens, R

    1949-06-20

    In previous notes (Compt. rend 228, 176 and 1218(1949)) two sorts of radioactive inclusions in igneous rocks, as recorded on photographic plates, were described: (1) very small (several microns) and strongly radioactive inclusions containing U and Th, (2) crystals of undertermined species, about 1 mm large, containing about 1% Th, and no U. The present note is a report on a third kind of inclusions, observed in a sand from Brittany and in a granite: having an area of several hundredths of mm/sup 2/, they are strongly radioactive; they contain Th, but little or no U; the Th content, which is about 76%, corresponds to pure thorite ThO/sub 2/.SiO/sub 2/.

  1. Shapes of Venusian 'pancake' domes imply episodic emplacement and silicic composition

    Science.gov (United States)

    Fink, Jonathan H.; Bridges, Nathan T.; Grimm, Robert E.

    1993-01-01

    The main evidence available for constraining the composition of the large circular 'pancake' domes on Venus is their gross morphology. Laboratory simulations using polyethylene glycol show that the height to diameter (aspect) ratios of domes of a given total volume depend critically on whether their extrusion was continuous or episodic, with more episodes leading to greater cooling and taller domes. Thus without observations of their emplacement, the compositions of Venusian domes cannot be uniquely constrained by their morphology. However, by considering a population of 51 Venusian domes to represent a sampling of many stages during the growth of domes with comparable histories, and by plotting aspect ratio versus total volume, we find that the shapes of the domes are most consistent with episodic emplacement. On Earth this mode of dome growth is found almost exclusively in lavas of dacite to rhyolite composition, strengthening earlier inferences about the presence of evolved magmas on Venus.

  2. Additive Construction with Mobile Emplacement (ACME)

    Science.gov (United States)

    Vickers, John

    2015-01-01

    The Additive Construction with Mobile Emplacement (ACME) project is developing technology to build structures on planetary surfaces using in-situ resources. The project focuses on the construction of both 2D (landing pads, roads, and structure foundations) and 3D (habitats, garages, radiation shelters, and other structures) infrastructure needs for planetary surface missions. The ACME project seeks to raise the Technology Readiness Level (TRL) of two components needed for planetary surface habitation and exploration: 3D additive construction (e.g., contour crafting), and excavation and handling technologies (to effectively and continuously produce in-situ feedstock). Additionally, the ACME project supports the research and development of new materials for planetary surface construction, with the goal of reducing the amount of material to be launched from Earth.

  3. Magma Dynamics at Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    D. Krier

    2005-08-29

    Small-volume basaltic volcanic activity at Yucca Mountain has been identified as one of the potential events that could lead to release of radioactive material from the U.S. Department of Energy (DOE) designated nuclear waste repository at Yucca Mountain. Release of material could occur indirectly as a result of magmatic dike intrusion into the repository (with no associated surface eruption) by changing groundwater flow paths, or as a result of an eruption (dike intrusion of the repository drifts, followed by surface eruption of contaminated ash) or volcanic ejection of material onto the Earth's surface and the redistribution of contaminated volcanic tephra. Either release method includes interaction between emplacement drifts and a magmatic dike or conduit, and natural (geologic) processes that might interrupt or halt igneous activity. This analysis provides summary information on two approaches to evaluate effects of disruption at the repository by basaltic igneous activity: (1) descriptions of the physical geometry of ascending basaltic dikes and their interaction with silicic host rocks similar in composition to the repository host rocks; and (2) a summary of calculations developed to quantify the response of emplacement drifts that have been flooded with magma and repressurized following blockage of an eruptive conduit. The purpose of these analyses is to explore the potential consequences that could occur during the full duration of an igneous event.

  4. Magma Dynamics at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    D. Krier

    2005-01-01

    Small-volume basaltic volcanic activity at Yucca Mountain has been identified as one of the potential events that could lead to release of radioactive material from the U.S. Department of Energy (DOE) designated nuclear waste repository at Yucca Mountain. Release of material could occur indirectly as a result of magmatic dike intrusion into the repository (with no associated surface eruption) by changing groundwater flow paths, or as a result of an eruption (dike intrusion of the repository drifts, followed by surface eruption of contaminated ash) or volcanic ejection of material onto the Earth's surface and the redistribution of contaminated volcanic tephra. Either release method includes interaction between emplacement drifts and a magmatic dike or conduit, and natural (geologic) processes that might interrupt or halt igneous activity. This analysis provides summary information on two approaches to evaluate effects of disruption at the repository by basaltic igneous activity: (1) descriptions of the physical geometry of ascending basaltic dikes and their interaction with silicic host rocks similar in composition to the repository host rocks; and (2) a summary of calculations developed to quantify the response of emplacement drifts that have been flooded with magma and repressurized following blockage of an eruptive conduit. The purpose of these analyses is to explore the potential consequences that could occur during the full duration of an igneous event

  5. High level radioactive waste repositories. Task 3. Review of underground handling and emplacement. 1. Executive summary

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    A review is presented of proposals for transport, handling and emplacement of high-level radioactive waste in an underground repository appropriate to the U.K. context, with particular reference to waste block size and configuration; self-shielded or partially-shielded block; stages of disposal; transport by road/rail to repository site; handling techniques within repository; emplacement in vertical holes or horizontal tunnels; repository access by adit, incline or shaft; conventional and radiological safety; costs; and major areas of uncertainty requiring research or development.

  6. From Embodiment to Emplacement: Re-Thinking Competing Bodies, Senses and Spatialities

    Science.gov (United States)

    Pink, Sarah

    2011-01-01

    In this article I discuss how a shift from theories of embodiment to one of emplacement can inform how we understand the performing body in competitive and pedagogical contexts. I argue that recent theoretical advances concerning the senses, human perception and place offer new analytical possibilities for understanding skilled performances and…

  7. Mapping and characterization from aeromagnetic data of the Foum Zguid dolerite Dyke (Anti-Atlas, Morocco) a member of the Central Atlantic Magmatic Province (CAMP)

    Science.gov (United States)

    Bouiflane, Mustapha; Manar, Ahmed; Medina, Fida; Youbi, Nasrrddine; Rimi, Abdelkrim

    2017-06-01

    A high-resolution aeromagnetic survey was carried out in the Anti- Atlas, Morocco covering the main areas traversed by the Great CAMP Foum Zguid dyke (FZD). This ;doleritic; dyke belongs to the Central Atlantic Magmatic Province (CAMP), a Large Igneous Province which is associated with the fragmentation of the supercontinent Pangaea and the initial stages of rifting of the Central Atlantic Ocean. It also coincides in time with the mass extinction of the Triassic - Jurassic boundary. Based on the study of geological maps and Google Earth satellite images, it appears that the FZD is poorly exposed and, often covered by Quaternary deposits. This work proposes aeromagnetic modelling and interpretation of the FZD in order to better constrain its structural extent. The data have allowed (i) mapping of the dyke over great distances, under the Quaternary deposits and through areas where it was poorly characterized on the geological map; (ii) identifying major tectonic lineaments interpreted as faults; (iii) recognizing magnetic anomalies related to mafic intrusive bodies; and (iv) informing about regional structural context.

  8. The Mesozoic-Cenozoic igneous intrusions and related sediment-dominated hydrothermal activities in the South Yellow Sea Basin, the Western Pacific continental margin

    Science.gov (United States)

    Yumao, Pang; Xunhua, Zhang; Guolin, Xiao; Luning, Shang; Xingwei, Guo; Zhenhe, Wen

    2018-04-01

    Various igneous complexes were identified in multi-channel seismic reflection profiles from the South Yellow Sea Basin. It is not rare that magmatic intrusions in sedimentary basins cause strong thermal perturbations and hydrothermal activities. Some intrusion-related hydrothermal vent complexes have been identified and they are considered to originate from the deep sedimentary contact aureole around igneous intrusions and terminate in upper vents structures, and are linked by a vertical conduit system. The upper vent complexes are usually eye-shaped, dome-shaped, fault-related, crater-shaped or pock-shaped in seismic profiles. A schematic model was proposed to illustrate the structures of different types of hydrothermal vent complexes. A conceptual conduit model composed of an upper pipe-like part and a lower branching part was also derived. Hydrothermal vent complexes mainly developed during the Middle-Late Cretaceous, which is coeval with, or shortly after the intrusion. The back-arc basin evolution of the area which is related to the subduction of the Paleo-Pacific plate during the Mesozoic-Cenozoic may be the principal factor for voluminous igneous complexes and vent complexes in this area. It is significant to study the characteristics of igneous complexes and related hydrothermal vent complexes, which will have implications for the future study of this area.

  9. Composite Sunrise Butte pluton: Insights into Jurassic–Cretaceous collisional tectonics and magmatism in the Blue Mountains Province, northeastern Oregon

    Science.gov (United States)

    Johnson, Kenneth H.; Schwartz, J.J.; Žák, Jiří; Verner, Krystof; Barnes, Calvin G.; Walton, Clay; Wooden, Joseph L.; Wright, James E.; Kistler, Ronald W.

    2015-01-01

    The composite Sunrise Butte pluton, in the central part of the Blue Mountains Province, northeastern Oregon, preserves a record of subduction-related magmatism, arc-arc collision, crustal thickening, and deep-crustal anatexis. The earliest phase of the pluton (Desolation Creek unit) was generated in a subduction zone environment, as the oceanic lithosphere between the Wallowa and Olds Ferry island arcs was consumed. Zircons from this unit yielded a 206Pb/238U age of 160.2 ± 2.1 Ma. A magmatic lull ensued during arc-arc collision, after which partial melting at the base of the thickened Wallowa arc crust produced siliceous magma that was emplaced into metasedimentary rocks and serpentinite of the overthrust forearc complex. This magma crystallized to form the bulk of the Sunrise Butte composite pluton (the Sunrise Butte unit; 145.8 ± 2.2 Ma). The heat necessary for crustal anatexis was supplied by coeval mantle-derived magma (the Onion Gulch unit; 147.9 ± 1.8 Ma).The lull in magmatic activity between 160 and 148 Ma encompasses the timing of arc-arc collision (159–154 Ma), and it is similar to those lulls observed in adjacent areas of the Blue Mountains Province related to the same shortening event. Previous researchers have proposed a tectonic link between the Blue Mountains Province and the Klamath Mountains and northern Sierra Nevada Provinces farther to the south; however, timing of Late Jurassic deformation in the Blue Mountains Province predates the timing of the so-called Nevadan orogeny in the Klamath Mountains. In both the Blue Mountains Province and Klamath Mountains, the onset of deep-crustal partial melting initiated at ca. 148 Ma, suggesting a possible geodynamic link. One possibility is that the Late Jurassic shortening event recorded in the Blue Mountains Province may be a northerly extension of the Nevadan orogeny. Differences in the timing of these events in the Blue Mountains Province and the Klamath–Sierra Nevada Provinces suggest that

  10. Controls on Lava Flow Morphology and Propagation: Using Laboratory Analogue Experiments

    Science.gov (United States)

    Peters, S.; Clarke, A. B.

    2017-12-01

    The morphology of lava flows is controlled by eruption rate, composition, cooling rate, and topography [Fink and Griffiths, 1990; Gregg and Fink, 2000, 2006]. Lava flows are used to understand how volcanoes, volcanic fields, and igneous provinces formed and evolved [Gregg and Fink., 1996; Sheth, 2006]. This is particularly important for other planets where compositional data is limited and historical context is nonexistent. Numerical modeling of lava flows remains challenging, but has been aided by laboratory analog experiments [Gregg and Keszrthelyi, 2004; Soule and Cashman, 2004]. Experiments using polyethylene glycol (PEG) 600 wax have been performed to understand lava flow emplacement [Fink and Griffiths, 1990, 1992; Gregg and Fink, 2000]. These experiments established psi (hereafter denoted by Ψ), a dimensionless parameter that relates crust formation and advection timescales of a viscous gravity current. Four primary flow morphologies corresponding to discreet Ψ ranges were observed. Gregg and Fink [2000] also investigated flows on slopes and found that steeper slopes increase the effective effusion rate producing predicted morphologies at lower Ψ values. Additional work is needed to constrain the Ψ parameter space, evaluate the predictive capability of Ψ, and determine if the preserved flow morphology can be used to indicate the initial flow conditions. We performed 514 experiments to address the following controls on lava flow morphology: slope (n = 282), unsteadiness/pulsations (n = 58), slope & unsteadiness/pulsations (n = 174), distal processes, and emplacement vs. post-emplacement morphologies. Our slope experiments reveal a similar trend to Gregg and Fink [2000] with the caveat that very high and very low local & source eruption rates can reduce the apparent predictive capability of Ψ. Predicted Ψ morphologies were often produced halfway through the eruption. Our pulse experiments are expected to produce morphologies unique to each eruption rate

  11. The correlation between geomagnetic field reversals, Hawaiian volcanism, and the motion of the Pacific plate

    Directory of Open Access Journals (Sweden)

    W. Dong

    1996-06-01

    Full Text Available The correlation between geomagnetic field reversals and volcanism is investigated, according to the speculated consequence on volcanoes of the transient electric currents in the geodynamo, through Joule's heating, before and after every reversal event. We evaluate the temporal variation during the last ~ 70 Ma both of the magma emplacement rate Q(t from the Hawaii hot spot, and of the speed v(t of the Pacific plate, by means of the observed volumes of islands and seamounts along the Hawaii/Emperor Seamounts chain, and their respective radiometric datings. Results confirm expectations. A justification of the volcanic crises that lead to the generation of the large igneous provinces during the last ~ 250 Ma also emerged. We describe in detail the complex pattern of the timings of the different effects. Joule's power is generally responsible for ~ 75-80% of magmatism, and friction power only for ~ 20-25%; but, on some occasions almost ~ 100% is fuelled by friction alone. The visco-elastic coupling between lithosphere and asthenosphere results ~ 96% viscous, and ~ 4% elastic.

  12. Ocean redox change at the Permian-Triassic mass extinction

    DEFF Research Database (Denmark)

    Ruhl, Micha; Bjerrum, Christian J.; Canfield, Donald Eugene

    2013-01-01

    Earth’s history is marked by multiple events of ocean anoxia developing along continental margins and po¬tentially into the open ocean realm. These events of¬ten coincide with the emplacement of large igneous provinces (LIPs) on continents, major perturbations of global geochemical cycles and mar...... these oceanographic changes to similar observations for the Triassic-Jurassic mass extinction and discuss environmental forcing, poten¬tially inherent to major volcanic events and leading to global environmental change and extinction...... ocean redox change over the largest mass extinction event in Earth history, at the Permian-Tri¬assic boundary (at ~252 Ma). This event is marked by a major perturbation in the global exogenic carbon cycle (and associated major negative carbon isotope excursion (CIE)), likely initiated by carbon...... (anoxic but not euxinic) coinciding with the main extinction event. Molybdenum enrichments, often indicative for freely available sulfide in the water-column, only occur dur¬ing the second phase of euxinia. This pattern of ocean redox-change in Svalbard direct¬ly reflects similar trends in Greenland...

  13. Emplacement of rock avalanche material across saturated sediments, Southern Alp, New Zealand

    Science.gov (United States)

    Dufresne, A.; Davies, T. R.; McSaveney, M. J.

    2012-04-01

    The spreading of material from slope failure events is not only influenced by the volume and nature of the source material and the local topography, but also by the materials encountered in the runout path. In this study, evidence of complex interactions between rock avalanche and sedimentary runout path material were investigated at the 45 x 106 m3 long-runout (L: 4.8 km) Round Top rock avalanche deposit, New Zealand. It was sourced within myolinitic schists of the active strike-slip Alpine Fault. The narrow and in-failure-direction elongate source scarp is deep-seated, indicating slope failure was triggered by strong seismic activity. The most striking morphological deposit features are longitudinal ridges aligned radially to source. Trenching and geophysical surveys show bulldozed and sheared substrate material at ridge termini and laterally displaced sedimentary strata. The substrate failed at a minimum depth of 3 m indicating a ploughing motion of the ridges into the saturated material below. Internal avalanche compression features suggest deceleration behind the bulldozed substrate obstacle. Contorted fabric in material ahead of the ridge document substrate disruption by the overriding avalanche material deposited as the next down-motion hummock. Comparison with rock avalanches of similar volume but different emplacement environments places Round Top between longer runout avalanches emplaced over e.g. playa lake sediments and those with shorter travel distances, whose runout was apparently retarded by topographic obstacles or that entrained high-friction debris. These empirical observations indicate the importance of runout path materials on tentative trends in rock avalanche emplacement dynamics and runout behaviour.

  14. Subsurface geology of a potential waste emplacement site, Salt Valley Anticline, Grand County, Utah

    Science.gov (United States)

    Hite, R.J.

    1977-01-01

    The Salt Valley anticline, which is located about 32 km northeast of Moab, Utah, is perhaps one of the most favorable waste emplacement sites in the Paradox basin. The site, which includes about 7.8 km 2, is highly accessible and is adjacent to a railroad. The anticline is one of a series of northwest-trending salt anticlines lying along the northeast edge of the Paradox basin. These anticlines are cored by evaporites of the Paradox Member of the Hermosa Formation of Middle Pennsylvanian age. The central core of the Salt Valley anticline forms a ridgelike mass of evaporites that has an estimated amplitude of 3,600 m. The evaporite core consists of about 87 percent halite rock, which includes some potash deposits; the remainder is black shale, silty dolomite, and anhydrite. The latter three lithologies are referred to as 'marker beds.' Using geophysical logs from drill holes on the anticline, it is possible to demonstrate that the marker beds are complexly folded and faulted. Available data concerning the geothermal gradient and heatflow at the site indicate that heat from emplaced wastes should be rapidly dissipated. Potentially exploitable resources of potash and petroleum are present at Salt Valley. Development of these resources may conflict with use of the site for waste emplacement.

  15. Subsurface geology of a potential waste emplacement site, Salt Valley Anticline, Grand County, Utah

    International Nuclear Information System (INIS)

    Hite, R.J.

    1977-01-01

    The Salt Valley anticline, which is located about 32 km northeast of Moab, Utah, is perhaps one of the most favorable waste emplacement sites in the Paradox basin. The site, which includes about 7.8 km 2 , is highly accessible and is adjacent to a railroad. The anticline is one of a series of northwest-trending salt antilcines lying along the northeast edge of the Paradox basin. These anticlines are cored by evaporites of the Paradox Member of the Hermosa Formation of Middle Pennsylvanian age. The central core of the Salt Valley anticline forms a ridgelike mass of evaporites that has an estimated amplitude of 3,600 m. The evaporite core consists of about 87 percent halite rock, which includes some potash deposits; the remainder is black shale, silty dolomite, and anhydrite. The latter three lithologies are referred to as ''marker beds.'' Using geophysical logs from drill holes on the anticline, it is possible to demonstrate that the marker beds are complexly folded and faulted. Available data concerning the geothermal gradient and heatflow at the site indicate that heat from emplaced wastes should be rapidly dissipated. Potentially exploitable resources of potash and petroleum are present at Salt Valley. Development of these resources may conflict with use of the site for waste emplacement

  16. Ordovician A-type granitoid magmatism on the Ceará Central Domain, Borborema Province, NE-Brazil

    Science.gov (United States)

    Castro, Neivaldo A.; Ganade de Araujo, Carlos E.; Basei, Miguel A. S.; Osako, Liliane S.; Nutman, Alan A.; Liu, Dunyi

    2012-07-01

    We present field relationships, major and trace element geochemistry and U-Pb SHRIMP and ID-TIMS geochronology of the A-type Ordovician Quintas pluton located in the Ceará Central Domain of the Borborema Province, in northeastern Brazil. This pluton presents a concentric geometry and is composed mainly of syenogranite, monzogranite, quartz syenite to quartz monzodiorite, monzogabbro and diorite. Its geochemical characteristics [SiO2 (52-70%), Na2O/K2O (1.55-0.65), Fe2O3/MgO (2.2-7.3), metaluminous to sligthly alkaline affinity, post-collisional type in (Y + Nb) × Rb diagram, and A-type affinity (Ga > 22 ppm, Nb > 20 ppm, Zn > 60 ppm), REE fractioned pattern with negative Eu anomaly] are coherent with post-collisional A2-type granitoids. However, the emplacement of this pluton is to some extent temporally associated with the deposition of the first strata of the Parnaíba intracratonic basin, attesting also to a purely anorogenic character (A1-type granitoid). The emplacement of this pluton is preceded by one of the largest known orogenesis of the planet (Neoproterozoic Pan-African/Brasiliano) and, if it is classified as an A2-type granitoid, it provides interesting constraints about how long can last A2-type magmatic activity after a major collisional episode, arguably triggered by disturbance of the underlying mantle, a topic extensively debated in the geoscience community.

  17. Engineering for a disposal facility using the in-room emplacement method

    Energy Technology Data Exchange (ETDEWEB)

    Baumgartner, P; Bilinsky, D M; Ates, Y; Read, R S; Crosthwaite, J L; Dixon, D A

    1996-06-01

    This report describes three nuclear fuel waste disposal vaults using the in-room emplacement method. First, a generic disposal vault design is provided which is suitable for a depth range of 500 m to 1000 m in highly stressed, sparsely fractured rock. The design process is described for all components of the system. The generic design is then applied to two different disposal vaults, one at a depth of 750 m in a low hydraulically conductive, sparsely fractured rock mass and another at a depth of 500 m in a higher conductivity, moderately fractured rock mass. In the in-room emplacement method, the disposal containers with used-fuel bundles are emplaced within the confines of the excavated rooms of a disposal vault. The discussion of the disposal-facility design process begins with a detailed description of a copper-shell, packed-particulate disposal container and the factors that influenced its design. The disposal-room generic design is presented including the detailed specifications, the scoping and numerical thermal and thermal mechanical analyses, the backfilling and sealing materials, and the operational processes. One room design is provided that meets all the requirements for a vault depth range of 500 to 1000 m. A disposal-vault layout and the factors that influenced its design are also presented, including materials handling, general logistics, and separation of radiological and nonradiological operations. Modifications to the used-fuel packaging plant for the filling and sealing of the copper-shell, packed-particulate disposal containers and a brief description of the common surface facilities needed by the disposal vault and the packaging plant are provided. The implementation of the disposal facility is outlined, describing the project stages and activities and itemizing a specific plan for each of the project stages: siting, construction, operation; decommissioning; and closure. (author). 72 refs., 15 tabs., 63 figs.

  18. Engineering for a disposal facility using the in-room emplacement method

    International Nuclear Information System (INIS)

    Baumgartner, P.; Bilinsky, D.M.; Ates, Y.; Read, R.S.; Crosthwaite, J.L.; Dixon, D.A.

    1996-06-01

    This report describes three nuclear fuel waste disposal vaults using the in-room emplacement method. First, a generic disposal vault design is provided which is suitable for a depth range of 500 m to 1000 m in highly stressed, sparsely fractured rock. The design process is described for all components of the system. The generic design is then applied to two different disposal vaults, one at a depth of 750 m in a low hydraulically conductive, sparsely fractured rock mass and another at a depth of 500 m in a higher conductivity, moderately fractured rock mass. In the in-room emplacement method, the disposal containers with used-fuel bundles are emplaced within the confines of the excavated rooms of a disposal vault. The discussion of the disposal-facility design process begins with a detailed description of a copper-shell, packed-particulate disposal container and the factors that influenced its design. The disposal-room generic design is presented including the detailed specifications, the scoping and numerical thermal and thermal mechanical analyses, the backfilling and sealing materials, and the operational processes. One room design is provided that meets all the requirements for a vault depth range of 500 to 1000 m. A disposal-vault layout and the factors that influenced its design are also presented, including materials handling, general logistics, and separation of radiological and nonradiological operations. Modifications to the used-fuel packaging plant for the filling and sealing of the copper-shell, packed-particulate disposal containers and a brief description of the common surface facilities needed by the disposal vault and the packaging plant are provided. The implementation of the disposal facility is outlined, describing the project stages and activities and itemizing a specific plan for each of the project stages: siting, construction, operation; decommissioning; and closure. (author)

  19. Radiometric ages of some igneous rocks from the southern and southwestern coalfields of New South Wales

    International Nuclear Information System (INIS)

    Carr, P.F.; Facer, R.A.

    1980-01-01

    Samples from six igneous rock units of the Southern and Southwestern Coalfields (Sydney Basin) of New South Wales have been dated using the K-Ar radiometric technique. The following ages were determined: a dolerite from Towradgi, 243 +- 10 MY; a dolerite from a diamond-drill hole at Sutton Forest, 202 +- 8 MY; the Bong Bong Basalt, 190 +- 8 MY; the Good Dog Lamprophyre, 101 +- 4 MY; a teschenite from South Bulli coal mine 74.0 +- 3.6 MY; and a dolerite from Robertson, 63.8 +- 3.2 MY. Combination of these new ages wth previously-published ages indicates that igneous activity in the Southern and Southwestern Coalfields occurred during four discrete periods of time - Middle-to-Late Permian; Late Triassic to Early Jurassic; mid-Cretaceous (only the Good Dog Lamprophyre has yielded such an age); and latest Cretaceous to Late Oligocene

  20. K-U-Th systematics of terrestrial igneous rocks for planetological comparisons: volcanic rocks of the Earth oceanic island arc and Venus surface material

    International Nuclear Information System (INIS)

    Nikolaeva, O.V.

    1997-01-01

    Principles of the formation o data base for 339 samples of oceanic island arc (OIA) igneous rocks of the Earth available in literature are described as well as of the formation of fresh rock sample, characteristics of this sample, and K-U-Th-systematics of the fresh igneous rocks of Earth OIA. Results of comparison of the Venus measured rocks and Earth OIA rocks by K, U, Th

  1. Supplemental Performance Analyses for Igneous Activity and Human Intrusion at the Potential High-Level Nuclear Waste Repository at Yucca Mountain

    International Nuclear Information System (INIS)

    Swift, P.; Gaither, K.; Freeze, G.; McCord, J.; Kalinich, D.; Saulnier, G.; Statham, W.

    2002-01-01

    The U.S. Department of Energy (DOE) is considering the possible recommendation of a site at Yucca Mountain, Nevada, for the potential development of a geologic repository for the disposal of high-level radioactive waste and spent nuclear fuel. Consequences of hypothetical disruption of the Yucca Mountain site by igneous activity or human intrusion have been evaluated in the Yucca Mountain Science and Engineering Report (S and ER) (1), which presents technical information supporting the consideration of the possible site recommendation. Since completion of the S and ER, supplemental analyses have examined possible impacts of new information and alternative assumptions on the estimates of the consequences of these events. Specifically, analyses of the consequences of igneous disruption address uncertainty regarding: (1) the impacts of changes in the repository footprint and waste package spacing on the probability of disruption; (2) impacts of alternative assumptions about the appropriate distribution of future wind speeds to use in the analysis; (3) effects of alternative assumptions about waste particle sizes; and (4) alternative assumptions about the number of waste packages damaged by igneous intrusion; and (5) alternative assumptions about the exposure pathways and the biosphere dose conversion factors used in the analysis. Additional supplemental analyses, supporting the Final Environmental Impact Statement (FEIS), have examined the results for both igneous disruption and human intrusion, recalculated for a receptor group located 18 kilometers (km) from the repository (the location specified in 40 CFR 197), rather than at the 20 km distance used in the S and ER analyses

  2. Magnetic fabrics in characterization of magma emplacement and tectonic evolution of the Moyar Shear Zone, South India

    Directory of Open Access Journals (Sweden)

    P. Pratheesh

    2013-01-01

    Full Text Available The Moyar Shear Zone (MSZ of the South Indian granulite terrain hosts a prominent syenite pluton (∼560 Ma and associated NW-SE to NE-SW trending mafic dyke swarm (∼65 Ma and 95 Ma. Preliminary magnetic fabric studies in the mafic dykes, using Anisotropy of Magnetic Susceptibly (AMS studies at low-field, indicate successive emplacement and variable magma flow direction. Magnetic lineation and foliation in these dykes are identical to the mesoscopic fabrics in MSZ mylonites, indicating shear zone guided emplacement. Spatial distribution of magnetic lineation in the dykes suggests a common conduit from which the source magma has been migrated. The magnetic foliation trajectories have a sigmoidal shape to the north of the pluton and curve into the MSZ suggesting dextral sense of shear. Identical fabric conditions for magnetic fabrics in the syenite pluton and measured field fabrics in mylonite indicate syntectonic emplacement along the Proterozoic crustal scale dextral shear zone with repeated reactivation history.

  3. Hanford 100-N Area In Situ Apatite and Phosphate Emplacement by Groundwater and Jet Injection: Geochemical and Physical Core Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Szecsody, James E.; Vermeul, Vincent R.; Fruchter, Jonathan S.; Williams, Mark D.; Rockhold, Mark L.; Qafoku, Nikolla; Phillips, Jerry L.

    2010-07-01

    The purpose of this study is to evaluate emplacement of phosphate into subsurface sediments in the Hanford Site 100-N Area by two different technologies: groundwater injection of a Ca-citrate-PO4 solution and water-jet injection of sodium phosphate and/or fish-bone apatite. In situ emplacement of phosphate and apatite adsorbs, then incorporates Sr-90 into the apatite structure by substitution for calcium. Overall, both technologies (groundwater injection of Ca-citrate-PO4) and water-jet injection of sodium phosphate/fish-bone apatite) delivered sufficient phosphate to subsur¬face sediments in the 100-N Area. Over years to decades, additional Sr-90 will incorporate into the apatite precipitate. Therefore, high pressure water jetting is a viable technology to emplace phosphate or apatite in shallow subsurface sediments difficult to emplace by Ca-citrate-PO4 groundwater injections, but further analysis is needed to quantify the relevant areal extent of phosphate deposition (in the 5- to 15-ft distance from injection points) and cause of the high deposition in finer grained sediments.

  4. A Change in Igneous Activity of the Jack Hills Zircon Sources ca. 3.9 Ga

    Science.gov (United States)

    Bell, E. A.; Harrison, T. M.

    2010-12-01

    New Ti-in-zircon crystallization temperature (Txlln) data for Jack Hills zircons reveal that the tight clustering of Hadean grains around a Txlln of 680°C, possibly indicative of felsic-to-intermediate minimum melting conditions, continues to ~3.92 Ga. Between 3.92-3.82 Ga the 680°C clustering ceases and most concordant grains cluster around an apparent Txlln of 610°C. A small group of zircons with higher Txlln (~750°C), present during the Hadean, is also observed during this period. After 3.82 Ga a Hadean-like distribution resumes for ~100 Ma. This large, concordant, low-Ti group at ~3.9 Ga is statistically distinct from the Hadean distribution and appears to be unique in the Jack Hills zircon record. The existence of coeval high- and low-Ti groups suggests that two distinct zircon-forming processes are distinguishable ~3.9 Ga, unlike during the Hadean. The significant numbers of zircons with apparent Txlln below 600°C may be suggestive of subsolidus formation, since igneous units with solidii below 600°C are relatively rare. The higher-Ti group is more consistent with an intermediate to mafic igneous origin but metamorphic overprinting or subsolidus formation at granulite grade cannot be ruled out by Txlln alone. A substantial proportion of the high-Ti group display oscillatory and disrupted oscillatory zoning in cathodoluminescence images, usually indicative of igneous origins and later metamorphism, respectively; most low-Ti grains are homogeneous. Several of each group display patchy zonation indicative of metamorphic overprinting. Although several grains with apparent Txlln >600°C display oscillatory zonation, the majority of the low-Ti group do not show textural evidence for igneous origins. We interpret these results to indicate the transition from a mechanism(s) that produced dominantly 680°C apparent zircon temperatures at ca. 3.9 Ga to include a new zircon-forming process in the sediment source(s), likely a protracted period of metamorphism

  5. State of the art for fabricating and emplacing concrete containers into large horizontal disposal caverns in the french geological repository - 59267

    International Nuclear Information System (INIS)

    Bosgiraud, Jean-Michel; Guariso, Maurice; Pineau, Francois

    2012-01-01

    The research and development work presented in this paper was initialized by Andra in 2007. The work necessary for manufacturing and testing a full scale demonstrator is presently implemented. The case story is twofold. The first part is related to the initial development of a high performance concrete formulation used for fabricating concrete storage containers (containing Intermediate Level and Long Lived Waste primary canisters) to be stacked and emplaced into 400-m long concrete lined horizontal disposal vaults (also called cavern), excavated in the Callovo-Oxfordian clay host formation at a 550 to 600-m depth, with an inside diameter of approximately 8-m. The fabrication of the concrete boxes is illustrated. The second part presents the outcome at the end of the detailed design phase, for a system which is now being manufactured (for further test and assembly), for the emplacement of the concrete containers inside the vault. The application was engineered for remote emplacing a pile of 2 concrete containers (the containers are preliminarily stacked in a pile of 2, inside a hot cell, thanks to a ground travelling gantry crane). The emplacement process is justified and the related emplacement synoptic is illustrated. The test campaign is scheduled in 2011-2012. The successful completion of the technical trials is mandatory to confirm the mechanical feasibility of remotely emplacing concrete containers into large horizontal disposal caverns over long distances. The later display of the machinery at work in Andra's showroom will be instrumental for the confidence building process involving the various stakeholders concerned by the public enquiry period (mid-2013) preceding the deep geological repository license application (2014-2015). (authors)

  6. Geology and porphyry copper-type alteration-mineralization of igneous rocks at the Christmas Mine, Gila County, Arizona

    Science.gov (United States)

    Koski, Randolph A.

    1979-01-01

    The Christmas copper deposit, located in southern Gila County, Arizona, is part of the major porphyry copper province of southwestern North America. Although Christmas is known for skarn deposits in Paleozoic carbonate rocks, ore-grade porphyry-type copper mineralization also occurs in a composite granodioritic intrusive complex and adjacent mafic volcanic country rocks. This study considers the nature, distribution, and genesis of alteration-mineralization in the igneous rock environment at Christmas. At the southeast end of the Dripping Spring Mountains, the Pennsylvanian Naco Limestone is unconformably overlain by the Cretaceous Williamson Canyon Volcanics, a westward-thinning sequence of basaltic volcanic breccia and lava flows, and subordinate clastic sedimentary rocks. Paleozoic and Mesozoic strata are intruded by Laramide-age dikes, sills, and small stocks of hornblende andesite porphyry and hornblende rhyodacite porphyry, and the mineralized Christmas intrusive complex. Rocks of the elongate Christmas stock, intruded along an east-northeast-trending fracture zone, are grouped into early, veined quartz diorite (Dark Phase), biotite granodiorite porphyry (Light Phase), and granodiorite; and late, unveined dacite porphyry and granodiorite porphyry. Biotite rhyodacite porphyry dikes extending east and west from the vicinity of the stock are probably coeval with biotite granodiorite porphyry. Accumulated normal displacement of approximately 1 km along the northwest-trending Christmas-Joker fault system has juxtaposed contrasting levels (lower, intrusive-carbonate rock environment and upper, intrusive-volcanic rock environment) within the porphyry copper system. K-Ar age determinations and whole-rock chemical analyses of the major intrusive rock types indicate that Laramide calc-alkaline magmatism and ore deposition at Christmas evolved over an extended period from within the Late Cretaceous (~75-80 m.y. ago) to early Paleocene (~63-61 m.y. ago). The sequence of

  7. WP EMPLACEMENT CONTROL AND COMMUNICATION EQUIPMENT DESCRIPTIONS

    International Nuclear Information System (INIS)

    Raczka, N.T.

    1997-01-01

    The objective and scope of this document are to list and briefly describe the major control and communication equipment necessary for waste package emplacement at the proposed nuclear waste repository at Yucca Mountain. Primary performance characteristics and some specialized design features of the required equipment are explained and summarized in the individual subsections of this document. This task was evaluated in accordance with QAP-2-0 and found not to be quality affecting. Therefore, this document was prepared in accordance with NAP-MG-012. The following control and communication equipment are addressed in this document: (1) Programmable Logic Controllers (PLC's); (2) Leaky Feeder Radio Frequency Communication Equipment; (3) Slotted Microwave guide Communication Equipment; (4) Vision Systems; (5) Radio Control Equipment; and (6) Enclosure Cooling Systems

  8. Petrography, geochemistry, and geochronology of the Cenozoic Cape Crossfire, Cape King, and No Ridge igneous complexes (northern Victoria Land, Antarctica)

    International Nuclear Information System (INIS)

    Rocchi, S.; Fioretti, A.M.; Cavazzini, G.

    2002-01-01

    The Meander Intrusive Group is the plutonic-subvolcanic counterpart of the McMurdo Volcanic Group, and extends along 200 km of the Ross Sea coast of Northern Victoria Land. The three largest occurrences of the Meander Intrusive Group between the Icebreaker and Borchgrevink glaciers are the Cape Crossfire, the No Ridge, and the Cape King igneous complexes. These have an area of 40-80 square km and are composed of dominant monzogabbros and monzodiorites along with minor syenites and alkali feldspar microgranites. A significant compositional gap exists between mafic and felsic facies, which show geometrical relationships varying from subhorizontal alternating layers to complex pillowing and fragmentation of the mafic into the felsic facies. Two whole rock biotite Rb-Sr internal isochrons constrain the cooling age of Cape Crossfire Igneous Complex at 31 Ma, a few million years older than No Ridge and Cape King igneous complexes. Thus, the ages of these complexes (≤ 31 Ma) are younger than the plutons and dikes (≥ 35 Ma) cropping out in the southernmost area between the Campbell and Icebreaker glaciers. (author). 28 refs., 8 figs., 3 tabs

  9. Vent Complexes above Dolerite Sills in Phanerozoic LIPs: Implications for Proterozoic LIPs and IOCG Deposits

    Science.gov (United States)

    Ernst, R. E.; Bleeker, W.; Svensen, H.; Planke, S.; Polozov, A. G.

    2009-05-01

    New insights into the origin of IOCG (iron oxide copper gold) deposits [e.g., 1, 2, 3] follow from recent studies of Phanerozoic Large Igneous Provinces (LIPs). Detailed seismic studies of the 62-55 Ma North Atlantic Igneous Province and complementary studies in the 183 Ma Karoo and 250 Ma Siberian LIPs reveal thousands of hydrothermal vent complexes (HVCs). Up to 5-10 km across at the paleosurface, these vents connect to underlying dolerite sills at paleodepths of up to 8 km [4, 5, 6, 7]. They originate from explosive release of gases generated when thick sills (>50 m) are emplaced into volatile-rich but low-permeability sedimentary strata. HVCs are phreatomagmatic in origin. Their architecture, economic potential for IOCG-type deposits, and effects on climate strongly depend on the type of host rocks (black shales at Karoo and evaporites at Siberian LIPs) and its fluid (brines) saturation at the time of emplacement. About 250 HVCs associated with the Siberian LIP are mineralized having magnetite in the matrix. Some are being mined for Fe (Korshunovskoe and Rudnogorskoe), but their economic potential for copper and gold mineralization is understudied. These observations from the Phanerozoic LIP record suggest that HVCs should also be an essential component of sill provinces associated with Proterozoic LIPs, with a potential for causing major climatic shifts and IOCG-type deposits, particularly if the host sediments include substantial evaporites. Two examples are discussed here. The 725 Ma Franklin LIP covers 1.1 Mkm2 in northern Canada [8]; in the Minto Inlier of Victoria Island, this event comprises volcanics, sills, and breccia pipes [9, 10]. The breccia pipes appear identical to HVCs and, furthermore, the presence of evaporites in the host sediments of the Shaler Supergroup suggests (based on the Siberian trap example) the potential for IOCG-type mineralization. Could 1.59 Ga sills, as exemplified by the exposed Western Channel Diabase sills on the eastern

  10. Physical Volcanological and Petrogenetic Implications of Intra-lava Flow Geochemical Heterogeneity in the Columbia River Flood Basalt Province, USA.

    Science.gov (United States)

    Vye, C. L.; Barry, T. L.; Self, S.; Gannoun, A.; Burton, K. W.

    2007-12-01

    Continental flood basalt lava flows are widely assumed to represent compositionally uniform and rapidly erupted products of large well-mixed magma reservoirs. However, this study presents new data to illustrate systematic element and isotope variations within the flow field formed by an individual flood basalt eruption, both vertically within each sheet lobe and laterally between the constituent lobes. Such variation is significant in chemostratigraphic correlation of flood basalt lava units, in identifying source variability during one eruption, and in petrogenetic modeling. We investigate the extent and cause of compositional variation through tracing lava sheet lobes in a 2,660 cubic kilometer pahoehoe flow field formed during a single eruption in the Columbia River Basalt Province, USA. This is based on features related to emplacement by the inflation mechanism. This method of emplacement is supported by small but statistically significant and systematic major and trace element variation e.g. MgO 3.09- 4.55 wt%, Ni 17.5-25.6 ppm, indicative of fractional crystallisation. Re-Os isotopes indicate progressive crustal contamination of the magma over the timescale of a single flood basalt eruption. By establishing this physical volcanological framework, we determine a temporal link with the supply of lava from the vent(s) and apply it to investigate sequential magmatic evolution during the timescale of one eruption.

  11. Determination of emplacement mechanism of Zafarghand granitoid Pluton (Southeast of Ardestan by using anisotropy of magnetic susceptibility method (AMS

    Directory of Open Access Journals (Sweden)

    Mahmoud Sadeghian

    2017-03-01

    Full Text Available Zafarghand granitoid pluton with compositional range from gabbro to granite and early to middle Miocene age cropped out about 35 km of SE Ardestan. This pluton intrudedthe Eocene volcanic and volcanosedimentary rocks of the Urumieh - Dokhtar structuralzone. In this research, for the first time, the emplacement mechanism of Zafarghandgranitoidic pluton method has been investigated using of anisotropy of magneticsusceptibility (AMS. Based on field observations, as well as petrography andinterpretations of magnetic parameters, Zafarghand pluton divided into 5 domains (1A,1B, 2, 3, 4 and 5. Domain 1, in turn, is divided into 1A and 1B. Domains 2 and 4 arelithologically, gabbro to quartzdiorite and have been emplaced first. They have playedas feeder zones. Domains 1A, 1B, 3, and 5 are dominantly granodioritic to graniticcomposition and have been emplaced as a big and low dip magmatic flow (or possibly as a sill. The occurrence of gabbro to quartzdiorite as well as grandiorite, granite andtonalite in the margin borders of the body, are all indication of magma mixing. It isshould be noted that during emplacement of the pluton studied, fractionalcrystallization, magma mixing and crustal contamination contributed to its generationand the evolution as well.

  12. Evaluation of the post-emplacement environment of high level radioactive waste packages at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Glassley, W.

    1989-01-01

    Evaluation of the post-emplacement environment around high-level radioactive waste containers is required by federal regulations. The information derived from this evaluation will be used to determine the service performance of the waste containers, the chemical and hydrological conditions that may influence radionuclide release and transport if containers are breached, and retrievability of the waste containers prior to closure of the repository. Laboratory studies, numerical simulations, and field experiments and tests are used to provide data necessary for this evaluation. Results obtained to date demonstrate that the post-emplacement environment in the welded tuff at Yucca Mountain, Nevada maintains relatively benign chemical features (i.e., near neutral pH, low concentrations of dissolved species) for most scenarios. The hydrological environment appears to be one of low flow volume and rates for the expected condition of an unsaturated medium. Emplacement borehole stability will be a function of fracture density and orientation, which may be influenced by microcrack development. Field studies and numerical simulations are in progress that will extend the results of laboratory studies to long time periods. The extent to which chemical, hydrological and mechanical processes can be adequately coupled through numerical simulations remains a matter of concern

  13. Characterisation and genesis of the Singhbhum uranium province, India

    International Nuclear Information System (INIS)

    Mahadevan, T.M.

    1988-01-01

    The Singhbhum Uranium province is characterised by the late Archaean predominantly granitic Singhbhum Craton and the associated Proterozoic mobile belts, the boundaries of which are marked by major crustal dislocations. The Singhbhum craton had two-phase evolution during the time range 4000-2900 million years and its stabilisation around 2900 million years was marked by the emplacement of K-rich granitoids and the early crustal enrichment of uranium. Two distinctive types of uranium mineralisation occur in the Province - (i) the early Quartz Pebble Conglomerate (QPC) type and (ii) the later economically most significant shear-controlled hydrothermal type. The QPC type is confined to the cratonic volcano-sedimentary basins, characterised by basal fluvial high-energy deposits, near-continental volcanics and banded iron formations spanning the time band of 2900-2500 million years. The shear controlled hydrothermal mineralisation is predominantly developed in a 200 km-long arcuate zone of intense and deep tectonisation, acid-(?) alkaline-basic magmatism, hydrothermal activity and metallogenesis. This shear zone represents a belt of intense crust-mantle interaction. Uranium mineralisation is polyphasic, polymetallic. The mineralogy is complex and the chemistry of the ores is greatly influenced by the lithology of the host rocks involved in the shear. Part of the shear zone grazing the Dhanjori, predominantly volcanic supra-crustals is richer in U, Cu, Ni, Mo and also contains minor Bi, Au, Ag, Te and Se, while the western trans-Dhanjori sector of the shear zone characterised by schists and quartzites with lesser volcanic component is relatively poorer in these metals. The ore bodies in the trans-Dhanjori sector are more peneconcordant, gradational, stratabound and have spherical variograms, while those in the Dhanjori sector are transgressive, sharp, highly mobilised, vein type with Dewijsian variograms. A synthesis leads to the conclusion that uranium mineralisation is

  14. Petrografic description of some igneous rocks from the Cordillera of South Mendoza, in the Argentine

    NARCIS (Netherlands)

    Kuenen, Ph.H.

    1926-01-01

    Comparatively little is yet known of the intricate igneous history of the Cordillera of South Mendoza. Almost all the knowledge we have is due to the field- and stratigraphical work of Dr. H. Gerth of Leiden (bibl. 1 and 2), and the petrographic studies of Dr. H. G. Backlund (bibl. 3 and 4) on the

  15. Fore arc tectonothermal evolution of the El Oro metamorphic province (Ecuador) during the Mesozoic

    Science.gov (United States)

    Riel, Nicolas; Martelat, Jean-Emmanuel; Guillot, Stéphane; Jaillard, Etienne; Monié, Patrick; Yuquilema, Jonatan; Duclaux, Guillaume; Mercier, Jonathan

    2014-10-01

    The El Oro metamorphic province of SW Ecuador is a composite massif made of juxtaposed terranes of both continental and oceanic affinity that has been located in a fore-arc position since Late Paleozoic times. Various geochemical, geochronological, and metamorphic studies have been undertaken on the El Oro metamorphic province, providing an understanding of the origin and age of the distinct units. However, the internal structures and geodynamic evolution of this area remain poorly understood. Our structural analysis and thermal modeling in the El Oro metamorphic province show that this fore-arc zone underwent four main geological events. (1) During Triassic times (230-225 Ma), the emplacement of the Piedras gabbroic unit at crustal-root level ( 9 kbar) triggered partial melting of the metasedimentary sequence under an E-W extensional regime at pressure-temperature conditions ranging from 4.5 to 8.5 kbar and from 650 to 900°C for the migmatitic unit. (2) At 226 Ma, the tectonic underplating of the Arenillas-Panupalí oceanic unit (9 kbar and 300°C) thermally sealed the fore-arc region. (3) Around the Jurassic-Cretaceous boundary, the shift from trench-normal to trench-parallel subduction triggered the exhumation and underplating of the high-pressure, oceanic Raspas Ophiolitic Complex (18 kbar and 600°C) beneath the El Oro Group (130-120 Ma). This was followed by the opening of a NE-SW pull-apart basin, which tilted the massif along an E-W subhorizontal axis (110 Ma). (4) In Late Cretaceous times, an N-S compressional event generated heterogeneous deformation due to the presence of the Cretaceous Celica volcanic arc, which acted as a buttress and predominantly affected the central and eastern part of the massif.

  16. Far-field thermomechanical response of argillaceous rock to emplacement of a nuclear-waste repository

    International Nuclear Information System (INIS)

    McVey, D.F.; Thomas, R.K.; Lappin, A.R.

    1980-08-01

    Before heat-producing wastes can be emplaced safely in any argillaceous rock, it will be necessary to understand the far-field thermal and thermomechanical response of this rock to waste emplacement. This report presents the results of a first series of calculations aimed at estimating the far-field response of argillite to waste emplacement. Because the thermal and mechanical properties of argillite are affected by its content of expandable clay, its behavior is briefly compared and contrasted with that of a shale having the same matrix thermal properties, but containing no expandable clay. Under this assumption, modeled temperatures are the same for the two rock types at equivalent power densities and reflect the large dependence of in-situ temperatures on both initial power density and waste type. Thermomechanical calculations indicate that inclusion of contraction behavior of expandable clays in the assumed argillite thermal expansion behavior results, in some cases, in generation of a large zone in and near the repository that has undergone volumetric contraction but is surrounded by uniformly compressive stresses. Information available to date indicates that this contraction would likely result in locally increased fluid permeability and decreased in-situ thermal conductivity, but might well be advantageous as regards radionuclide retention, because of the increased surface area within the contracted zone. Assumption of continuous and positive expansion behavior for the shale eliminates the near-repository contraction and tensional zones, but results in near-surface tensional zones directly above the repository

  17. Natural radioactivity and radon exhalation rate in Brazilian igneous rocks

    Energy Technology Data Exchange (ETDEWEB)

    Moura, C.L.; Artur, A.C. [Departamento de Petrologia e Metalogenia, Instituto de Geociencias e Ciencias Exatas, Universidade Estadual Paulista (UNESP), Av. 24-A No. 1515, C.P. 178, CEP 13506-900, Rio Claro, Sao Paulo (Brazil); Bonotto, D.M., E-mail: danielbonotto@yahoo.com.b [Departamento de Petrologia e Metalogenia, Instituto de Geociencias e Ciencias Exatas, Universidade Estadual Paulista (UNESP), Av. 24-A No. 1515, C.P. 178, CEP 13506-900, Rio Claro, Sao Paulo (Brazil); Guedes, S. [Departamento de Cronologia e Raios Cosmicos, Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas (UNICAMP), Rua Sergio Buarque de Holanda No. 777, CEP 13083-859, Campinas, Sao Paulo (Brazil); Martinelli, C.D. [Departamento de Petrologia e Metalogenia, Instituto de Geociencias e Ciencias Exatas, Universidade Estadual Paulista (UNESP), Av. 24-A No. 1515, C.P. 178, CEP 13506-900, Rio Claro, Sao Paulo (Brazil)

    2011-07-15

    This paper reports the natural radioactivity of Brazilian igneous rocks that are used as dimension stones, following the trend of other studies on the evaluation of the risks to the human health caused by the rocks radioactivity as a consequence of their use as cover indoors. Gamma-ray spectrometry has been utilized to determine the {sup 40}K, {sup 226}Ra and {sup 232}Th activity concentrations in 14 rock types collected at different quarries. The following activity concentration range was found: 12.18-251.90 Bq/kg for {sup 226}Ra, 9.55-347.47 Bq/kg for {sup 232}Th and 407.5-1615.0 Bq/kg for {sup 40}K. Such data were used to estimate Ra{sub eq}, H{sub ex} and I{sub {gamma}}, which were compared with the threshold limit values recommended in literature. They have been exceeded for Ra{sub eq} and H{sub ex} in five samples, where the highest indices corresponded to a rock that suffered a process of ductile-brittle deformation that caused it a microbrecciated shape. The exhalation rate of Rn and daughters has also been determined in slabs consisting of rock pieces {approx}10 cm-long, 5 cm-wide and 3 cm-thick. It ranged from 0.24 to 3.93 Bq/m{sup 2}/h and exhibited significant correlation with eU (={sup 226}Ra), as expected. The results indicated that most of the studied rocks did not present risk to human health and may be used indoors, even with low ventilation. On the other hand, igneous rocks that yielded indices above the threshold limit values recommended in literature may be used outdoors without any restriction or indoors with ample ventilation.

  18. Using a Differential Scanning Calorimeter to Teach Phase Equilibria to Students of Igneous and Metamorphic Petrology

    Science.gov (United States)

    Maria, Anton H.; Millam, Evan L.; Wright, Carrie L.

    2011-01-01

    As an aid for teaching phase equilibria to undergraduate students of igneous and metamorphic petrology, we have designed a laboratory exercise that allows them to create a phase diagram from data produced by differential scanning calorimetry. By preparing and analyzing samples of naphthalene and phenanthrene, students acquire hands-on insight into…

  19. Scales of columnar jointing in igneous rocks: field measurements and controlling factors

    Science.gov (United States)

    Hetényi, György; Taisne, Benoît; Garel, Fanny; Médard, Étienne; Bosshard, Sonja; Mattsson, Hannes B.

    2012-03-01

    Columnar jointing is a common feature of solidified lavas, sills and dikes, but the factors controlling the characteristic stoutness of columns remain debated, and quantitative field observations are few in number. In this paper, we provide quantitative measurements on sizing of columnar joint sets and our assessment of the principal factors controlling it. We focus on (1) chemistry, as it is the major determinant of the physical (mechanical and thermal) properties of the lava, and (2) geology, as it influences the style of emplacement and lava geometry, setting boundary conditions for the cooling process and the rate of heat loss. In our analysis, we cover lavas with a broad range of chemical compositions (from basanite to phonolite, for six of which we provide new geochemical analyses) and of geological settings. Our field measurements cover 50 columnar jointing sites in three countries. We provide reliable, manually digitized data on the size of individual columns and focus the mathematical analysis on their geometry (23,889 data on side length, of which 17,312 are from full column sections and 3,033 data on cross-sectional area and order of polygonality). The geometrical observations show that the variation in characteristic size of columns between different sites exceeds one order of magnitude (side length ranging from 8 to 338 cm) and that the column-bounding polygons' average order is less than 6. The network of fractures is found to be longer than required by a minimum-energy hexagonal configuration, indicating a non-equilibrium, geologically quick process. In terms of the development and characteristic sizing of columnar joint sets, our observations suggest that columns are the result of an interplay between the geological setting of emplacement and magma chemistry. When the geological setting constrains the geometry of the emplaced body, it exerts a stronger control on characteristic column stoutness. At unconstrained geometries (e.g. unconfined lava

  20. Grains of Nonferrous and Noble Metals in Iron-Manganese Formations and Igneous Rocks of Submarine Elevations of the Sea of Japan

    Science.gov (United States)

    Kolesnik, O. N.; Astakhova, N. V.

    2018-01-01

    Iron-manganese formations and igneous rocks of submarine elevations in the Sea of Japan contain overlapping mineral phases (grains) with quite identical morphology, localization, and chemical composition. Most of the grains conform to oxides, intermetallic compounds, native elements, sulfides, and sulfates in terms of the set of nonferrous, noble, and certain other metals (Cu, Zn, Sn, Pb, Ni, Mo, Ag, Pd, and Pt). The main conclusion that postvolcanic hydrothermal fluids are the key sources of metals is based upon a comparison of the data of electron microprobe analysis of iron-manganese formations and igneous rocks dredged at the same submarine elevations in the Sea of Japan.

  1. Determination of fluorine by proton induced gamma ray emission (PIGE) spectrometry in igneous and metamorphic charnockitic rocks from Rogaland (S.W. Norway)

    International Nuclear Information System (INIS)

    Roelandts, I.; Robaye, G.; Weber, G.; Delbrouck, J.M.; Duchesne, J.C.

    1986-01-01

    More than 200 specimens from different occurrences of the Rogaland igneous complex and surrounding granulite facies metamorphic rocks (S.W. Norway) have been analysed by a direct non-destructive proton induced gamma ray emission (PIGE) technique. The fluorine contents vary from < 25 ppm to 3500 ppm. There is a good correlation between the concentration of fluorine and that of phosphorus for igneous rocks, suggesting a control of apatite on the F content. In metamorphic rocks, amphibole and biotite besides apatite are the principal concentrations of fluorine indicating that fluorine in the system is controlled by granulite facies metamorphism conditions. (author)

  2. The role of the geothermal gradient in the emplacement and replenishment of ground ice on Mars

    Science.gov (United States)

    Clifford, Stephen M.

    1993-01-01

    Knowledge of the mechanisms by which ground ice is emplaced, removed, and potentially replenished, are critical to understanding the climatic and hydrologic behavior of water on Mars, as well as the morphologic evolution of its surface. Because of the strong temperature dependence of the saturated vapor pressure of H2O, the atmospheric emplacement or replenishment of ground ice is prohibited below the depth at which crustal temperatures begin to monotonically increase due to geothermal heating. In contrast, the emplacement and replenishment of ground ice from reservoirs of H2O residing deep within the crust can occur by at least three different thermally-driven processes, involving all three phases of water. In this regard, Clifford has discussed how the presence of a geothermal gradient as small as 15 K/km can give rise to a corresponding vapor pressure gradient sufficient to drive the vertical transport of 1 km of water from a reservoir of ground water at depth to the base of the cryosphere every 10(exp 6) - 10(exp 7) years. This abstract expands on this earlier treatment by considering the influence of thermal gradients on the transport of H2O at temperatures below the freezing point.

  3. Postclosure performance assessment of the SCP [Site Characterization Plan] conceptual design for horizontal emplacement: Revision 1

    International Nuclear Information System (INIS)

    1987-08-01

    This report is a preliminary postclosure performance assessment of the repository design specified in the Site Characterization Plan Conceptual Design Report (SCP-CDR) for horizontal emplacement of high-level nuclear waste. At the time that these analyses were done, horizontal emplacement was the preferred orientation for the waste packages but vertical emplacement is now the reference design. This assessment consists of (1) a review of the regulatory requirements and strategy to demonstrate compliance with these requirements, (2) an analysis of the performance of the total repository system, (3) an analysis of the thermomechanical behavior of the repository, (4) an analysis of brine mobility in the repository, (5) an analysis of the waste package performance, (6) an analysis of the performance of seals, and (7) comments on the sensitivity of the various performance measures to uncertainties in the data and models. These are preliminary analyses and, in most cases, involve bounding calculations of the repository behavior. They have several purposes including (1) assessing how well this conceptual design ''measures up'' against requirements, (2) gaining experience in implementing the performance assessment strategy and tools and thereby learning where improvements are needed, (3) helping to identify needed data, and (4) helping to indicate required design modifications. 26 refs., 40 figs., 20 tabs

  4. La province des complexes annulaires alcalins sursaturés de l'adrar des Iforas, Mali

    Science.gov (United States)

    Ba, H.; Black, R.; Benziane, B.; Diombana, D.; Hascoet-Fender, J.; Bonin, B.; Fabre, J.; Liégeois, J. P.

    The Cambrian silica-saturated alkaline province of the Iforas is composed of about 15 massifs including typical large size ring complexes (20-30 km in diameter). Its originality is that it follows closely a regime of subduction blocked by the Pan-African collision (600 Ma) and that each stage of the transition from calcalkaline to alkaline can be related to structural elements in a geodynamic setting. Several complexes are described in some detail. The Kidal-Tibeljeljeline complex starts with the intrusion of syenite porphyries forming external ring dykes, often polygonal in outline, which are truncated by a central massif 30 km in diameter which is composed of a dozen major phases. It complexity is due to the individualization of several intrusive centres and to the fact that the erosional level coincides with that of the flat roof structures. Djounhane, Takellout and Timedjelalen (20-30 km in diameter) are simpler and composed of concentric intrusions youing inwards. Other occurrences are described briefly. The emplacement of all these intrusions at shallow depth in a rigid environment under a thick rhyolitic cover of fissural origin is contemporary to movement along a tear fault system with intermittent periods of distension as shown by spectacular associated dyke swarms. The study shows the presence of both peralkaline and aluminous trends, an evolution of the minerals (pyroxenes, amphiboles and micas), and geochemical characteristics that are quite comparable to those of anorogenic provinces such as Niger and Nigeria. It is important to note, however, the absence of cassiterite and the predominance of subsovus granites in the aluminous trend of the Iforas. The striking similarity between the provinces leads the authors to envisage a common mantle origin, the difference being due rather to the influence of the country rock.

  5. Using restored cross sections to evaluate magma emplacement, White Horse Mountains, Eastern Nevada, U.S.A.

    Science.gov (United States)

    Marko, Wayne T.; Yoshinobu, Aaron S.

    2011-03-01

    New field observations and cross section restoration from the Jurassic White Horse pluton-host rock system, Goshute Range, eastern Nevada, USA, indicate a sequential variation of host rock rheology attending magma emplacement. The pluton intruded weakly to nondeformed Devonian-Mississippian limestone, argillite and quartzite at shallow crustal levels (ca. 7 km). The contact aureole is well exposed along the southern, eastern and northern margin of the intrusive body and is less than 1 km wide. Rocks outside of the aureole are sub-horizontal and do not contain a penetrative fabric or are gently folded (interlimb angles > 120°) about sub-vertical axial planes. Within the contact aureole, continuous and discontinuous spaced, axial planar foliations and harmonic to disharmonic, tight to isoclinal folds wrap around the eastern margin of the pluton. Folds verge toward and away from the pluton and rim anticlines, synclines, and monoclines with wavelength in excess of 250 m are preserved along the pluton margin. The spatial proximity of these ductile structures to the pluton and the apparent increase in intensity of structure development approaching the pluton is compatible with contraction within the aureole attending pluton emplacement. However, all of the above structures are truncated by the intrusive contact at various scales. Granodioritic dikes ranging in thickness from 1 m up to ˜ 10 m emanate from the intrusion and cut host rock structure at high angles and turn to propagate towards one another, parallel to the pluton margin and host rock anisotropy. Such features are interpreted to reflect the last stages of diking and brittle deformation that modified the pluton contact after emplacement-related folding of the carbonate rocks, but before final solidification of the pluton. Eight serial geologic cross sections were constructed and evaluated to place geometric constraints on the shape and growth of the White Horse intrusion. Based on line-length restoration of

  6. Lithological suitability for HLW repository in Korea

    International Nuclear Information System (INIS)

    Kim, C.S.; Bae, D.S.; Kim, K.S.; Koh, Y.K.

    2001-01-01

    Regional geologic conditions of Korea were summarized with emphasis on rock mass and fracture system as a part of the research program for high level radioactive wastes disposal. The eastern margin of the Korea-China platform has been regarded as stable crotonic nature. The Mesozoic tectonic activities followed by igneous intrusion were the most vigorous crustal movement in the entire Korean peninsula. During the Jurassic-Cretaceous orogeny (180-130 Ma Bp), igneous activity resulted in forming a large batholith of Dab granitic rock (Jurassic granite). Rejuvenized igneous activities during the Cretaceous period formed the Bulguksa granite which are associated with felsic volcanic rocks and NE-SW/NNE-SSW geologic structures. The primary host rock is considered to be Daebo granite batholiths intruded in the geologic age of late Triassic to early Jurassic (205±15 Ma). The emplacement depths are in the range of 10-20 km and the crystallization occurs under the geopressure of 3∼7 kb. (author)

  7. Recurrent Early Cretaceous, Indo-Madagascar (89-86 Ma) and Deccan (66 Ma) alkaline magmatism in the Sarnu-Dandali complex, Rajasthan: 40Ar/39Ar age evidence and geodynamic significance

    Science.gov (United States)

    Sheth, Hetu; Pande, Kanchan; Vijayan, Anjali; Sharma, Kamal Kant; Cucciniello, Ciro

    2017-07-01

    The Sarnu-Dandali alkaline complex in Rajasthan, northwestern India, is considered to represent early, pre-flood basalt magmatism in the Deccan Traps province, based on a single 40Ar/39Ar age of 68.57 Ma. Rhyolites found in the complex are considered to be 750 Ma Malani basement. Our new 40Ar/39Ar ages of 88.9-86.8 Ma (for syenites, nephelinite, phonolite and rhyolite) and 66.3 ± 0.4 Ma (2σ, melanephelinite) provide clear evidence that whereas the complex has Deccan-age (66 Ma) components, it is dominantly an older (by 20 million years) alkaline complex, with rhyolites included. Basalt is also known to underlie the Early Cretaceous Sarnu Sandstone. Sarnu-Dandali is thus a periodically rejuvenated alkaline igneous centre, active twice in the Late Cretaceous and also earlier. Many such centres with recurrent continental alkaline magmatism (sometimes over hundreds of millions of years) are known worldwide. The 88.9-86.8 Ma 40Ar/39Ar ages for Sarnu-Dandali rocks fully overlap with those for the Indo-Madagascar flood basalt province formed during continental breakup between India (plus Seychelles) and Madagascar. Recent 40Ar/39Ar work on the Mundwara alkaline complex in Rajasthan, 120 km southeast of Sarnu-Dandali, has also shown polychronous emplacement (over ≥ 45 million years), and 84-80 Ma ages obtained from Mundwara also arguably represent post-breakup stages of the Indo-Madagascar flood basalt volcanism. Remnants of the Indo-Madagascar province are known from several localities in southern India but hitherto unknown from northwestern India 2000 km away. Additional equivalents buried under the vast Deccan Traps are highly likely.

  8. Preliminary uncertainty analysis of pre-waste-emplacement groundwater travel times for a proposed repository in basalt

    International Nuclear Information System (INIS)

    Clifton, P.M.; Arnett, R.C.

    1984-01-01

    Preliminary uncertainty analyses of pre-waste-emplacement groundwater travel times are presented for a potential high-level nuclear waste repository in the deep basalts beneath the Hanford Site, Washington State. The uncertainty analyses are carried out by means of a Monte Carlo technique, which requires the uncertain inputs to be described as either random variables or spatial stochastic processes. Pre-waste-emplacement groundwater travel times are modeled in a continuous, flat-lying basalt flow top that is assumed to overlie the repository horizon. Two-dimensional, steady state groundwater flow is assumed, and transmissivity, effective thickness, and regional hydraulic gradient are considered as uncertain inputs. Groundwater travel time distributions corresponding to three groundwater models are presented and compared. Limitations of these preliminary simulation results are discussed in detail

  9. High water content in primitive continental flood basalts.

    Science.gov (United States)

    Xia, Qun-Ke; Bi, Yao; Li, Pei; Tian, Wei; Wei, Xun; Chen, Han-Lin

    2016-05-04

    As the main constituent of large igneous provinces, the generation of continental flood basalts (CFB) that are characterized by huge eruption volume (>10(5) km(3)) within short time span (primitive CFB in the early Permian Tarim large igneous province (NW China), using the H2O content of ten early-formed clinopyroxene (cpx) crystals that recorded the composition of the primitive Tarim basaltic melts and the partition coefficient of H2O between cpx and basaltic melt. The arc-like H2O content (4.82 ± 1.00 wt.%) provides the first clear evidence that H2O plays an important role in the generation of CFB.

  10. Novel Emplacement Device for a Very Deep Borehole Disposal

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Min Soo; Choi, Heui-joo; Lee, Jong Yul [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    There is a worldwide attempt of HLW disposal into a very deep borehole of around 3-5 km depth with the advancement of an underground excavation technology recently. As it goes into deeper underground, the rock becomes more uniform and flawless. And then the underground water circulation system at 3-5 km depth is almost disconnected with near groundwater circulation system. The canister integrity is less important in this very deep borehole disposal system unlike a general geologic disposal system at 500 m. In the deep borehole disposal procedures, one SNF (Spent Nuclear Fuel) assembly is stored in one disposal canister (D30-40cm, H4.7-5.0m), and approximately 10-40 disposal canisters are connected axially, which parade length can leach to around 200m in maximum. The connected canister parade is lowered through a very deep borehole (D40-50cm) by emplacement devices. Therefore the connections between canisters and canister to lowering joint are very important for the safe operation of it. The well-known connection method between canisters is Threaded Coupled Connection method, in which releasing of the connection is almost impossible after thread fastening in the borehole. The novel joint device suggested in this paper can accommodate a canister emplacement and retrieval in the borehole disposal process. The joint can be lowered by bound to a drilling pipe, or high tension cable along 3-5 km distance. This novel device can cope with an accidental event easily without any joint head change. When canisters are damaged or stuck on the borehole wall during their descending, the canisters in trouble can be retrieved simply by the control of a lifting speed.

  11. Petrologic Modeling of Magmatic Evolution in The Elysium Volcanic Province

    Science.gov (United States)

    Susko, D.; Karunatillake, S.; Hood, D.

    2017-12-01

    The Elysium Volcanic Province (EVP) on Mars is a massive expanse of land made up of many hundreds of lava flows of various ages1. The variable surface ages within this volcanic province have distinct elemental compositions based on the derived values from the Gamma Ray Spectrometer (GRS) suite2. Without seismic data or ophiolite sequences on Mars, the compositions of lavas on the surface provide some of the only information to study the properties of the interior of the planet. The Amazonian surface age and isolated nature of the EVP in the northern lowlands of Mars make it ideal for analyzing the mantle beneath Elysium during the most recent geologic era on Mars. The MELTS algorithm is one of the most commonly used programs for simulating compositions and mineral phases of basaltic melt crystallization3. It has been used extensively for both terrestrial applications4 and for other planetary bodies3,5. The pMELTS calibration of the algorithm allows for higher pressure (10-30 kbars) regimes, and is more appropriate for modeling melt compositions and equilibrium conditions for a source within the martian mantle. We use the pMELTS program to model how partial melting of the martian mantle could evolve magmas into the surface compositions derived from the GRS instrument, and how the mantle beneath Elysium has changed over time. We attribute changes to lithospheric loading by long term, episodic volcanism within the EVP throughout its history. 1. Vaucher, J. et al. The volcanic history of central Elysium Planitia: Implications for martian magmatism. Icarus 204, 418-442 (2009). 2. Susko, D. et al. A record of igneous evolution in Elysium, a major martian volcanic province. Scientific Reports 7, 43177 (2017). 3. El Maarry, M. R. et al. Gamma-ray constraints on the chemical composition of the martian surface in the Tharsis region: A signature of partial melting of the mantle? Journal of Volcanology and Geothermal Research 185, 116-122 (2009). 4. Ding, S. & Dasgupta, R. The

  12. Age of origin of the polymetamorphosed Copperton Formation, Namaqua-Natal Province, determined by single grain zircon Pb-Pb dating

    International Nuclear Information System (INIS)

    Cornell, D.H.; Griffin, G.; Kroener, A.; Humphreys, H.

    1990-01-01

    The Copperton Formation of the Areachap Group in the Northern Cape Province is a strongly metamorphosed, predominantly metavolcanic unit which contains several massive sulphide deposits. Previous work on this unit has established a complex metamorphic history, the four main phases of which are fairly well dated by a combination of methods; however, the age of origin is still poorly constrained. Zircons extracted from the Smouspan Gneiss Member of the Copperton formation are euhedral and show a crystal habit which indicates an igneous and probably volcanic origin, with no discernable metamorphic component. Whole-grain thermal evaporation on four such zircon grains yielded a precise set of 207 Pb/ 206 Pb data which establishes a 1 285 ± 14 Ma age for the origin of the Smouspan Gneiss and Copperton Formation. Indications of a ∼1 600 Ma age from other parts of the Areachap Group should be treated with caution until more reliable data are obtained. 9 figs., 2 tabs., 29 refs

  13. Compilation of new and previously published geochemical and modal data for Mesoproterozoic igneous rocks of the St. Francois Mountains, southeast Missouri

    Science.gov (United States)

    du Bray, Edward A.; Day, Warren C.; Meighan, Corey J.

    2018-04-16

    The purpose of this report is to present recently acquired as well as previously published geochemical and modal petrographic data for igneous rocks in the St. Francois Mountains, southeast Missouri, as part of an ongoing effort to understand the regional geology and ore deposits of the Mesoproterozoic basement rocks of southeast Missouri, USA. The report includes geochemical data that is (1) newly acquired by the U.S. Geological Survey and (2) compiled from numerous sources published during the last fifty-five years. These data are required for ongoing petrogenetic investigations of these rocks. Voluminous Mesoproterozoic igneous rocks in the St. Francois Mountains of southeast Missouri constitute the basement buried beneath Paleozoic sedimentary rock that is over 600 meters thick in places. The Mesoproterozoic rocks of southeast Missouri represent a significant component of approximately 1.4 billion-year-old (Ga) igneous rocks that crop out extensively in North America along the southeast margin of Laurentia and subsequent researchers suggested that iron oxide-copper deposits in the St. Francois Mountains are genetically associated with ca. 1.4 Ga magmatism in this region. The geochemical and modal data sets described herein were compiled to support investigations concerning the tectonic setting and petrologic processes responsible for the associated magmatism.

  14. Anoxia, toxic metals and acidification: volcanically-driven causes of the Middle Permian (Capitanian) mass extinction in NW Pangaea?

    Science.gov (United States)

    Bond, David; Grasby, Stephen; Wignall, Paul

    2017-04-01

    The controversial Capitanian (Middle Permian, 262 Ma) mass extinction, mostly known from equatorial latitudes, has recently been identified in a Boreal setting in Spitsbergen. We now document this extinction in the record of brachiopods from the Sverdrup Basin in NW Pangaea (Ellesmere Island, Canada), confirming Middle Permian losses as a global crisis on par with the "Big Five". Redox proxies (pyrite framboids and trace metals) show that the high latitude crisis coincided with an intensification of oxygen-poor conditions - a potent killer that is not clearly developed in lower latitude sections. Mercury becomes briefly enriched in strata at the level of the Middle Permian extinction level in Spitsbergen and Ellesmere Island, indicating voluminous but short-lived volcanism that is likely to have been the emplacement of the Emeishan large igneous province (LIP) in SW China. A potent cocktail of poisons appears to have impacted across the Boreal Realm, whilst the near-total loss of carbonates near the extinction level is also consistent with reduced pH across the region. Multiple stresses, possibly with origins in low-latitude LIP volcanism, are therefore implicated in the Middle Permian extinction and there was no respite even in the far-distant Boreal Realm.

  15. Did mantle plume magmatism help trigger the Great Oxidation Event?

    Science.gov (United States)

    Ciborowski, T. Jake. R.; Kerr, Andrew C.

    2016-03-01

    The Great Oxidation Event (GOE) represents the first sustained appearance of free oxygen in Earth's atmosphere. This fundamental event in Earth's history has been dated to approximately 2450 million years ago (Ma), that is, hundreds of millions of years after the appearance of photosynthetic cyanobacteria in the fossil record. A variety of mechanisms have been suggested to explain this time lag between the onset of photosynthesis and atmospheric oxygenation, including orogenesis, changes in the areal extent and distribution of continental shelves, the secular release of hydrogen to space, and methanogenic bacterial stress. Recently, it has been proposed that subaerial volcanism during the early Proterozoic could have provided a large pulse of sulphate to the ancient oceans, the reduction of which liberated the oxygen to drive the GOE. Here we show that the Matachewan Large Igneous Province (LIP), which is partially preserved in Scandinavia and North America, is both exactly coincident with the onset of the GOE, and of sufficient magnitude to be the source of this sulphate release. We therefore propose that the volcanism associated with the emplacement of the Matachewan LIP was a principal driver of the oxygenation of our planet.

  16. Unravelling the Volcanological Complexities of a Flood Basalt Province: Volcanology, Paleomagnetism and Geochemistry, From the Deccan Volcanic Province

    Science.gov (United States)

    Jay, A. E.; Widdowson, M.; Self, S.; Mac Niocaill, C.

    2006-12-01

    The lavas of the Deccan Volcanic Province (DVP), India, were erupted across the Cretaceous-Tertiary boundary (KTB) and, as such, have been suggested as a candidate for causing the KTB mass extinction event. Understanding the development of such large outpourings of lava is essential to deducing their environmental impact. Detailed flow-by-flow logging was undertaken along four roads up the Mahabaleshwar Plateau, and a further three road sections to the north and south were investigated in order to study the volcanological style of this area of the DVP. Logging along the four roads which ascend the Mahabaleshwar Plateau was combined with detailed geochemical and paleomagnetic sampling and provides the first integrated study of its kind in the DVP. The logging demonstrated that almost all the lavas encountered were inflated pahoehoe sheet lobes. No `a'a flows were encountered and one rubbly pahoehoe flow may have been observed. Statistical analyses of XRF trace element data, and the occurrence of differing thicknesses and numbers of lava units between the paleomagnetic reversal horizon (Chron 29r/29n) and the top of the Ambenali Formation, suggest that individual sheet lobes are not greater than the width of the Plateau c. 20 km. This provides an explanation for the topography, up to 95 m in our study area, on the surface of the DVP at the time when the lavas were being erupted. As the sheet lobes were emplaced and inflated they left areas uncovered by lava, the topographic difference between these two areas could be many 10s of metres, and as this process occurred over the whole DVP the topographic differences could increase. As well as topography, this leads to other complexities. When later lavas in-fill these depressions it causes them to occur physically lower in the sequence than older lavas. This demonstrates that the previously held concept of large, flat-lying sheets lobes covering vast tracts of the province is not probable, as on the local scale tracing

  17. Characterize Framework for Igneous Activity at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Perry, F.; Youngs, B.

    2000-01-01

    The purpose of this Analysis/Model (AMR) report is twofold. (1) The first is to present a conceptual framework of igneous activity in the Yucca Mountain region (YMR) consistent with the volcanic and tectonic history of this region and the assessment of this history by experts who participated in the Probabilistic Volcanic Hazard Analysis (PVHA) (CRWMS M and O 1996). Conceptual models presented in the PVHA are summarized and extended in areas in which new information has been presented. Alternative conceptual models are discussed as well as their impact on probability models. The relationship between volcanic source zones defined in the PVHA and structural features of the YMR are described based on discussions in the PVHA and studies presented since the PVHA. (2) The second purpose of the AMR is to present probability calculations based on PVHA outputs. Probability distributions are presented for the length and orientation of volcanic dikes within the repository footprint and for the number of eruptive centers located within the repository footprint (conditional on the dike intersecting the repository). The probability of intersection of a basaltic dike within the repository footprint was calculated in the AMR ''Characterize Framework for Igneous Activity at Yucca Mountain, Nevada'' (CRWMS M and O 2000g) based on the repository footprint known as the Enhanced Design Alternative [EDA II, Design B (CRWMS M and O 1999a; Wilkins and Heath 1999)]. Then, the ''Site Recommendation Design Baseline'' (CRWMS M and O 2000a) initiated a change in the repository design, which is described in the ''Site Recommendation Subsurface Layout'' (CRWMS M and O 2000b). Consequently, the probability of intersection of a basaltic dike within the repository footprint has also been calculated for the current repository footprint, which is called the 70,000 Metric Tons of Uranium (MTU) No-Backfill Layout (CRWMS M and O 2000b). The calculations for both footprints are presented in this AMR. In

  18. Characterize Framework for Igneous Activity at Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    F. Perry; B. Youngs

    2000-11-06

    The purpose of this Analysis/Model (AMR) report is twofold. (1) The first is to present a conceptual framework of igneous activity in the Yucca Mountain region (YMR) consistent with the volcanic and tectonic history of this region and the assessment of this history by experts who participated in the Probabilistic Volcanic Hazard Analysis (PVHA) (CRWMS M&O 1996). Conceptual models presented in the PVHA are summarized and extended in areas in which new information has been presented. Alternative conceptual models are discussed as well as their impact on probability models. The relationship between volcanic source zones defined in the PVHA and structural features of the YMR are described based on discussions in the PVHA and studies presented since the PVHA. (2) The second purpose of the AMR is to present probability calculations based on PVHA outputs. Probability distributions are presented for the length and orientation of volcanic dikes within the repository footprint and for the number of eruptive centers located within the repository footprint (conditional on the dike intersecting the repository). The probability of intersection of a basaltic dike within the repository footprint was calculated in the AMR ''Characterize Framework for Igneous Activity at Yucca Mountain, Nevada'' (CRWMS M&O 2000g) based on the repository footprint known as the Enhanced Design Alternative [EDA II, Design B (CRWMS M&O 1999a; Wilkins and Heath 1999)]. Then, the ''Site Recommendation Design Baseline'' (CRWMS M&O 2000a) initiated a change in the repository design, which is described in the ''Site Recommendation Subsurface Layout'' (CRWMS M&O 2000b). Consequently, the probability of intersection of a basaltic dike within the repository footprint has also been calculated for the current repository footprint, which is called the 70,000 Metric Tons of Uranium (MTU) No-Backfill Layout (CRWMS M&O 2000b). The calculations for both

  19. Ferroan Dolomitization by Seawater Interaction with Mafic Igneous Dikes and Carbonate Host Rock at the Latemar Platform, Dolomites, Italy: Numerical Modeling of Spatial, Temporal, and Temperature Data

    Directory of Open Access Journals (Sweden)

    K. Blomme

    2017-01-01

    Full Text Available Numerous publications address the petrogenesis of the partially dolomitized Latemar carbonate platform, Italy. A common factor is interpretation of geochemical data in terms of heating via regional igneous activity that provided kinetically favorable conditions for replacement dolomitization. New field, petrographic, XRD, and geochemical data demonstrate a spatial, temporal, and geochemical link between replacement dolomite and local mafic igneous dikes that pervasively intrude the platform. Dikes are dominated by strongly altered plagioclase and clinopyroxene. Significantly, where ferroan dolomite is present, it borders dikes. We hypothesize that seawater interacted with mafic minerals, causing Fe enrichment in the fluid that subsequently participated in dolomitization. This hypothesis was tested numerically through thermodynamic (MELTS, Arxim-GEM and reactive flow (Arxim-LMA simulations. Results confirm that seawater becomes Fe-enriched during interaction with clinopyroxene (diopside-hedenbergite and plagioclase (anorthite-albite-orthoclase solid solutions. Reaction of modified seawater with limestone causes ferroan and nonferroan replacement dolomitization. Dolomite quantities are strongly influenced by temperature. At 40 to 80°C, ferroan dolomite proportions decrease with increasing temperature, indicating that Latemar dolomitization likely occurred at lower temperatures. This relationship between igneous dikes and dolomitization may have general significance due to the widespread association of carbonates with rifting-related igneous environments.

  20. Thermal impact of waste emplacement and surface cooling associated with geologic disposal of nuclear waste

    International Nuclear Information System (INIS)

    Wang, J.S.Y.; Mangold, D.C.; Spencer, R.K.; Tsang, C.F.

    1982-01-01

    The age of nuclear waste - the length of time between its removal from the reactor cores and its emplacement in a repository - is a significant factor in determining the thermal loading of a repository. The surface cooling period as well as the density and sequence of waste emplacement affects both the near-field repository structure and the far-field geologic environment. To investigate these issues, a comprehensive review was made of the available literature pertaining to thermal effects and thermal properties of mined geologic repositories. This included a careful evaluation of the effects of different surface cooling periods of the wastes, which is important for understanding the optimal thermal loading of a repository. The results led to a clearer understanding of the importance of surface cooling in evaluating the overall thermal effects of a radioactive waste repository. The principal findings from these investigations are summarized in this paper

  1. Understanding the mechanical coupling between magma emplacement and the resulting deformation: the example of saucer-shaped sills

    Science.gov (United States)

    Galland, O.; Neumann, E. R.; Planke, S.

    2009-12-01

    The mechanical coupling between magma intrusions and the surrounding rocks plays a major role in the emplacement of volcanic plumbing systems. The deformation associated with magma emplacement has been widely studied, such as caldera inflation/deflation, volcano deformation during dike intrusion, and doming above laccoliths. However, the feedback processes, i.e. the effect of deformation resulting from intruding magma on the propagation of the intrusion itself, have rarely been studied. Saucer-shaped sills are adequate geological objects to understand such processes. Indeed, observation show that saucer-shaped sills are often associated with dome-like structures affecting the overlying sediments. In addition, there is a clear geometrical relation between the sills and the domes: the dome diameters are almost identical to those of saucers, and the tips of the inclined sheets of saucers are superimposed on the edges of the domes. In this presentation, we report on experimental investigations of the emplacement mechanisms of saucer-shaped sills and associated deformation. The model materials were (1) cohesive fine-grained silica flour, representing brittle crust, and (2) molten low-viscosity oil, representing magma. A weak layer located at the top of the injection inlet simulates strata. The main variable parameter is injection depth. During experiments, the surface of the model is digitalized through a structured light technique based on the moiré projection principle. Such a tool provides topographic maps of the surface of the model and allows a periodic (every 1.5 s) monitoring of the model topography. When the model magma starts intruding, a symmetrical dome rises above the inlet. Subsequently, the dome inflates and widens, and then evolves to a plateau-like feature, with nearly flat upper surface and steep sides. At the end of the experiments, the intruding liquid erupts at the edge of the plateau. The intrusions formed in the experiments are saucer-shaped sills

  2. Conceptual designs for waste packages for horizontal or vertical emplacement in a repository in salt for reference in the site characterization plan

    International Nuclear Information System (INIS)

    1987-06-01

    This report includes the options of horizontal and vertical emplacement, the addition of a phased repository, an additional waste form (intact spent fuel), revised geotechnical data appropriate for the Deaf Smith County site, new corrosion data for the container, and new repository design data. The waste package consists of waste form and canister within a thick-walled, low-carbon steel container surrounded by packing. The container is a hollow cylinder with a flat head welded to each end. The design concepts for the waste container or vertical and horizontal emplacement are identical. This report discusses the results of analyses of aspects of the reference waste package concept needing changes because of new data and information believed applicable to the Deaf Smith County site. Included are waste package conceptual designs or (1) the reference defense high-level waste form from the Savannah River Plant; (2) intact spent fuel with our pressurized-water-reactor or nine boiling-water-reactor assemblies per package for emplacement during Phase 1 of repository operation; and (3) spent fuel which has been disassembled and consolidated into a segmented cylindrical canister with rods from either 12 pressurized-water-reactor or 30 boiling-water-reactor assemblies per package for emplacement during Phase 2. 30 refs., 61 figs., 30 tabs

  3. Mechanical degradation of Emplacement Drifts at Yucca Mountain - A Modeling Case Study. Part I: Nonlithophysal Rock

    International Nuclear Information System (INIS)

    M. Lin; D. Kicker; B. Damjanac; M. Board; M. Karakouzian

    2006-01-01

    This paper outlines rock mechanics investigations associated with mechanical degradation of planned emplacement drifts at Yucca Mountain, which is the designated site for the proposed U.S. high-level nuclear waste repository. The factors leading to drift degradation include stresses from the overburden, stresses induced by the heat released from the emplaced waste, stresses due to seismically related ground motions, and time-dependent strength degradation. The welded tuff emplacement horizon consists of two groups of rock with distinct engineering properties: nonlithophysal units and lithophysal units, based on the relative proportion of lithophysal cavities. The term 'lithophysal' refers to hollow, bubble like cavities in volcanic rock that are surrounded by a porous rim formed by fine-grained alkali feldspar, quartz, and other minerals. Lithophysae are typically a few centimeters to a few decimeters in diameter. Part I of the paper concentrates on the generally hard, strong, and fractured nonlithophysal rock. The degradation behavior of the tunnels in the nonlithophysal rock is controlled by the occurrence of keyblocks. A statistically equivalent fracture model was generated based on extensive underground fracture mapping data from the Exploratory Studies Facility at Yucca Mountain. Three-dimensional distinct block analyses, generated with the fracture patterns randomly selected from the fracture model, were developed with the consideration of in situ, thermal, and seismic loads. In this study, field data, laboratory data, and numerical analyses are well integrated to provide a solution for the unique problem of modeling drift degradation

  4. Thermal simulation of drift emplacement. Geotechnical and geophysical investigations in and around backfilled galleries

    International Nuclear Information System (INIS)

    Schneefub, J.U.; Gommlich, G.E.

    1988-01-01

    The concept for the direct disposal of spent fuel in rock salt foresees the emplacement of large waste canisters on the floor of a disposal gallery. Subsequent to emplacement the drift is backfilled with salt grit. In a demonstration test six cylindrical containments are to be emplaced within distances of 3 m from each other in two parallel galleries of 14 m 2 , separated by a pillar of 10 m thickness. They will be heated up by a power output of approx. 1 kW/m to 200 degree C surface temperature by electrical heaters. The thermal and mechanical response of the salt rock and the backfilling to the artificial heating is to be investigated as follows: (1) measurement of the temperature field at the contained surface, in the backfill and in the rock salt; (2) deformation measurements of the salt rock around the heated drifts; (3) measurements of tunnel convergence in heated and unheated sections; (4) compaction measurements of the backfilling in heated and unheated areas; (5) measurement of rock stresses in areas very close to the galleries; and (6) pressure measurements in the backfilling, between backfilling and rock, and between backfilling and containers. The rock burst monitoring system of the Asse salt mine will be expanded to this special field of the mine to detect seismic events due to thermomechanical effects. Another seismoacoustic system will be installed to observe the compaction of the backfilling. This system must be calibrated for the relation between the density and velocities of seismic waves. It is planned to monitor the density by gamma-gamma log measurements. The changes in overall density during the entire experiment will be observed by gravimeter measurements of high precision

  5. Implementation of the full-scale emplacement (FE) experiment at the Mont Terri rock laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Müller, H.R.; Garitte, B.; Vogt, T.; and others

    2017-04-15

    Opalinus Clay is currently being assessed as the host rock for a deep geological repository for high-level and low- and intermediate-level radioactive wastes in Switzerland. Within this framework, the 'Full-Scale Emplacement' (FE) experiment was initiated at the Mont Terri rock laboratory close to the small town of St-Ursanne in Switzerland. The FE experiment simulates, as realistically as possible, the construction, waste emplacement, backfilling and early post-closure evolution of a spent fuel/vitrified high-level waste disposal tunnel according to the Swiss repository concept. The main aim of this multiple heater test is the investigation of repository-induced thermo-hydro-mechanical (THM) coupled effects on the host rock at this scale and the validation of existing coupled THM models. For this, several hundred sensors were installed in the rock, the tunnel lining, the bentonite buffer, the heaters and the plug. This paper is structured according to the implementation timeline of the FE experiment. It documents relevant details about the instrumentation, the tunnel construction, the production of the bentonite blocks and the highly compacted 'granulated bentonite mixture' (GBM), the development and construction of the prototype 'backfilling machine' (BFM) and its testing for horizontal GBM emplacement. Finally, the plug construction and the start of all 3 heaters (with a thermal output of 1350 Watt each) in February 2015 are briefly described. In this paper, measurement results representative of the different experimental steps are also presented. Tunnel construction aspects are discussed on the basis of tunnel wall displacements, permeability testing and relative humidity measurements around the tunnel. GBM densities achieved with the BFM in the different off-site mock-up tests and, finally, in the FE tunnel are presented. Finally, in situ thermal conductivity and temperature measurements recorded during the first heating months

  6. Effects of the deviation characteristics of nuclear waste emplacement boreholes on borehole liner stresses

    International Nuclear Information System (INIS)

    Glowka, D.A.

    1990-09-01

    This report investigates the effects of borehole deviation on the useability of lined boreholes for the disposal of high-level nuclear waste at the proposed Yucca Mountain Repository in Nevada. Items that lead to constraints on borehole deviation include excessive stresses that could cause liner failure and possible binding of a waste container inside the liner during waste emplacement and retrieval operations. Liner stress models are developed for two general borehole configurations, one for boreholes drilled with a steerable bit and one for boreholes drilled with a non-steerable bit. Procedures are developed for calculating liner stresses that arise both during insertion of the liner into a borehole and during the thermal expansion process that follows waste emplacement. The effects of borehole curvature on the ability of the waste container to pass freely inside the liner without binding are also examined. Based on the results, specifications on borehole deviation allowances are developed for specific vertical and horizontal borehole configurations of current interest. 11 refs., 22 figs., 4 tabs

  7. Emplacement mechanisms and structural influences of a younger granite intrusion into older wall rocks - a principal study with application to the Goetemar and Uthammar granites. Site-descriptive modelling SDM-Site Laxemar

    International Nuclear Information System (INIS)

    Cruden, Alexander R.

    2008-12-01

    The c. 1.80 Ga old bedrock in the Laxemar-Simpevarp area, which is the focus of the site investigation at Oskarshamn, is dominated by intrusive rocks belonging to the c. 1.86-1.65 Ga Transscandinavian Igneous Belt (TIB). However, the site investigation area is situated in between two c. 1.45 Ga old anorogenic granites, the Goetemar granite in the north and the Uthammar granite in the south. This study evaluates the emplacement mechanism of these intrusions and their structural influence on the older bedrock. Field observations and structural measurements indicate that both the Goetemar and the Uthammar granites are discordant and have not imposed any significant ductile deformation on their wall-rocks. The apparent conformity of geological contacts and fabrics in the wall rocks and the southern margin of the Goetemar granite is coincidental and inherited from the pattern of Svecokarelian deformation of the TIB. However, interpretation of regional aeromagnetic data suggests that the granites occur within a broad, NNE-SSW trending linear belt, pointing to deep seated tectonic control on their generation, ascent and emplacement. Thermochronology indicates that the granites were emplaced at depths between 4 and 8 km into brittle wall rocks. The 3-D shape of the Goetemar and Uthammar plutons has been investigated by 2.75D forward modelling of the residual gravity anomalies due to both granites. Both granites are associated with strong residual gravity anomalies of up to -10 mgal. Constraints on the geometry of the plutons at the surface are provided from surface geology maps and several deep boreholes located on or close to the model profiles. A further variable in the gravity modelling is introduced by either allowing the upper contact of the plutons to assume the most suitable orientation to produce the best fit between the modelled and observed gravity ('unconstrained models') or by forcing the near surface orientation of the contacts to be vertical ('constrained

  8. Emplacement mechanisms and structural influences of a younger granite intrusion into older wall rocks - a principal study with application to the Goetemar and Uthammar granites. Site-descriptive modelling SDM-Site Laxemar

    Energy Technology Data Exchange (ETDEWEB)

    Cruden, Alexander R. (Dept. of Geology, Univ. of Toronto (Canada))

    2008-12-15

    The c. 1.80 Ga old bedrock in the Laxemar-Simpevarp area, which is the focus of the site investigation at Oskarshamn, is dominated by intrusive rocks belonging to the c. 1.86-1.65 Ga Transscandinavian Igneous Belt (TIB). However, the site investigation area is situated in between two c. 1.45 Ga old anorogenic granites, the Goetemar granite in the north and the Uthammar granite in the south. This study evaluates the emplacement mechanism of these intrusions and their structural influence on the older bedrock. Field observations and structural measurements indicate that both the Goetemar and the Uthammar granites are discordant and have not imposed any significant ductile deformation on their wall-rocks. The apparent conformity of geological contacts and fabrics in the wall rocks and the southern margin of the Goetemar granite is coincidental and inherited from the pattern of Svecokarelian deformation of the TIB. However, interpretation of regional aeromagnetic data suggests that the granites occur within a broad, NNE-SSW trending linear belt, pointing to deep seated tectonic control on their generation, ascent and emplacement. Thermochronology indicates that the granites were emplaced at depths between 4 and 8 km into brittle wall rocks. The 3-D shape of the Goetemar and Uthammar plutons has been investigated by 2.75D forward modelling of the residual gravity anomalies due to both granites. Both granites are associated with strong residual gravity anomalies of up to -10 mgal. Constraints on the geometry of the plutons at the surface are provided from surface geology maps and several deep boreholes located on or close to the model profiles. A further variable in the gravity modelling is introduced by either allowing the upper contact of the plutons to assume the most suitable orientation to produce the best fit between the modelled and observed gravity ('unconstrained models') or by forcing the near surface orientation of the contacts to be vertical (&apos

  9. Transpressional granite-emplacement model: Structural and magnetic study of the Pan-African Bandja granitic pluton (West Cameroon)

    Science.gov (United States)

    Sandjo, A. F. Yakeu; Njanko, T.; Njonfang, E.; Errami, E.; Rochette, P.; Fozing, E.

    2016-02-01

    The Pan-African NE-SW elongated Bandja granitic pluton, located at the western part of the Pan-African belt in Cameroon, is a K-feldspar megacryst granite. It is emplaced in banded gneiss and its NW border underwent mylonitization. The magmatic foliation shows NE-SW and NNE-SSW strike directions with moderate to strong dip respectively in its northern and central parts. This mostly, ferromagnetic granite displays magnetic fabrics carried by magnetite and characterized by (i) magnetic foliation with best poles at 295/34, 283/33 and 35/59 respectively in its northern, central and southern parts and (ii) a subhorizontal magnetic lineation with best line at 37/8, 191/9 and 267/22 respectively in the northern, central and southern parts. Magnetic lineation shows an `S' shape trend that allows to (1) consider the complete emplacement and deformation of the pluton during the Pan-African D 2 and D 3 events which occurred in the Pan-African belt in Cameroon and (2) reorganize Pan-African ages from Nguiessi Tchakam et al. (1997) compared with those of the other granitic plutons in the belt as: 686 ±17 Ma (Rb/Sr) for D 1 age of metamorphism recorded in gneiss; and the period between 604-557 Ma for D 2-D 3 emplacement and deformation age of the granitic pluton in a dextral ENE-WSW shear movement.

  10. Activity of radioactive inclusions in igneous rocks

    Energy Technology Data Exchange (ETDEWEB)

    Coppens, R

    1949-01-10

    It has been shown by Hee (Compt. rend. 227, 356(1948)) that the radioactivity of igneous rocks is traceable to radioactive inclusions. The present author used the photoemulsion method for the determination of U and Th content of rocks, by counting ..cap alpha.. tracks produced by such inclusions, per cm/sup 2/ and per sec. Rock powder was placed upon Ilford C/sub 2/ emulsions, the exposition time varying between 7 and 18 days. In most cases, prolonged trajectories meet upon a well delineated small surface corresponding to the inclusions. The formula used is that given by I. Curie (J. Phys., (1946) Nov) which, after substitution of constants, has the form N = 8.4KC(U) + 2.5KC(Th); here N is the number of trajectories, C(U) and C(Th) are the concentrations of U and Th, and K is a coefficient varying between 14 for granite and 31 for uranium oxide and thorite. Using as a second equation C(Th) = 2.5C(U), the concentrations C(Th) and C(U) can be determined. The method was tested on seven samples of granitic sand and micaschist from Brittany. Their average contents was found to be about 10% U and 22% Th, with approximations of about 20%.

  11. The Influence of Topography on the Emplacement Dynamics of Martian Lava flows

    Science.gov (United States)

    Tremblay, J.; Fitch, E. P.; Fagents, S. A.

    2017-12-01

    Lava flows on the Martian surface exhibit a diverse array of complex morphologies. Previous emplacement models, based on terrestrial flows, do not fully account for these observed complex morphologies. We assert that the topography encountered by the flow can exert substantial control over the thermal, rheological, and morphological evolution of the flow, and that these effects can be better incorporated into flow models to predict Martian flow morphologies. Our development of an updated model can be used to account for these topographical effects and better constrain flow parameters. The model predicts that a slope break or flow meander induces eddy currents within the flow, resulting in the disruption of the flow surface crust. The exposure of the flow core results in accelerated cooling of the flow and a resultant increase in viscosity, leading to slowing of the flow. A constant source lava flux and a stagnated flow channel would then result in observable morphological changes, such as overflowing of channel levees. We have identified five morphological types of Martian flows, representing a range of effusion rates, eruption durations and topographic settings, which are suitable for application of our model. To characterize flow morphology, we used imaging and topographic data sets to collect data on flow dimensions. For eight large (50 to hundreds of km long) channelized flows in the Tharsis region, we used the MOLA 128 ppd DEM and/or individual MOLA shot points to derive flow cross-sectional thickness profiles, from which we calculated the cross-sectional area of the flow margins adjacent to the main channel. We found that the largest flow margin cross sectional areas (excluding the channel) occur in association with a channel bend, typically near the bend apex. Analysis of high-resolution images indicates that these widened flow margins are the result of repeated overflows of the channel levees and emplacement of short flow lobes adjacent to the main flow. In

  12. Beating the Heat: Magmatism in the Low-Temperature Thermochronologic Record

    Science.gov (United States)

    Murray, K. E.; Reiners, P. W.; Braun, J.; Karlstrom, L.; Morriss, M. C.

    2017-12-01

    of resetting around dikes compliments higher-temperature constraints on the longevity of magma flow from phase equilibria in partially melted wall rocks. In principal, this technique should also resolve along-strike variability in flow localization, providing novel constraints on eruptive flux in large igneous provinces.

  13. CLASSIFICATION OF THE MGR WASTE EMPLACEMENT/RETRIEVAL SYSTEM

    International Nuclear Information System (INIS)

    J.A. Ziegler

    2000-01-01

    The purpose of this analysis is to document the Quality Assurance (QA) classification of the Monitored Geologic Repository (MGR) waste emplacement/retrieved system structures, systems and components (SSCs) performed by the MGR Preclosure Safety and Systems Engineering Section. This analysis also provides the basis for revision of YMP/90-55Q, Q-List (YMP 2000). The Q-List identifies those MGR SSCs subject to the requirements of DOE/RW-0333P, Quality Assurance Requirements and Description (QARD) (DOE 2000). This QA classification incorporates the current MGR design and the results of the ''Design Basis Event Frequency and Dose Calculation for Site Recommendation'' (CRWMS M andO 2000a). The content and technical approach of this analysis is in accordance with the development plan ''QA Classification of MGR Structures, Systems, and Components'' (CRWMS M andO 1999b)

  14. Remote excavation using the telerobotic small emplacement excavator

    International Nuclear Information System (INIS)

    Thompson, D.H.; Burks, B.L.; Killough, S.M.

    1993-01-01

    Oak Ridge National Laboratory is developing remote excavation technologies for the Office of Technology Development, Robotics Technology Development Program. This work is being done to meet the need for remote excavation and removal of radioactive and contaminated buried waste at several DOE sites. System requirements are based on the need to uncover and remove waste from burial sites in a way that does not cause unnecessary personnel exposure or additional environmental contamination. Goals for the current project are to demonstrate dexterous control of a backhoe with force feedback and to implement robotic operations that will improve productivity. The Telerobotic Small Emplacement Excavator is a prototype system that incorporates the needed robotic and telerobotic capabilities on a commercially available platform. The ability to add remote dexterous teleoperation and robotic operating modes is intended to be adaptable to other commercially available excavator systems

  15. Relating rock avalanche morphology to emplacement processes

    Science.gov (United States)

    Dufresne, Anja; Prager, Christoph; Bösmeier, Annette

    2015-04-01

    The morphology, structure and sedimentological characteristics of rock avalanche deposits reflect both internal emplacement processes and external influences, such as runout path characteristics. The latter is mainly predisposed by topography, substrate types, and hydrogeological conditions. Additionally, the geological setting at the source slope controls, e.g. the spatial distribution of accumulated lithologies and hence material property-related changes in morphology, or the maximum clast size and amount of fines of different lithological units. The Holocene Tschirgant rock avalanche (Tyrol, Austria) resulted from failure of an intensely deformed carbonate rock mass on the southeast face of a 2,370-m-high mountain ridge. The initially sliding rock mass rapidly fragmented as it moved towards the floor of the Inn River valley. Part of the 200-250 x 106 m3 (Patzelt 2012) rock avalanche debris collided with and moved around an opposing bedrock ridge and flowed into the Ötz valley, reaching up to 6.3 km from source. Where the Tschirgant rock avalanche spread freely it formed longitudinal ridges aligned along motion direction as well as smaller hummocks. Encountering high topography, it left runup ridges, fallback patterns (i.e. secondary collapse), and compressional morphology (successively elevated, transverse ridges). Further evidence for the mechanical landslide behaviour is given by large volumes of mobilized valley-fill sediments (polymict gravels and sands). These sediments indicate both shearing and compressional faulting within the rock avalanche mass (forming their own morphological units through, e.g. in situ bulldozing or as distinctly different hummocky terrain), but also indicate extension of the spreading landslide mass (i.e. intercalated/injected gravels encountered mainly in morphological depressions between hummocks). Further influences on its morphology are given by the different lithological units. E.g. the transition from massive dolomite

  16. Geochronological Constraints on the Exhumation and Emplacement of Subcontinental Lithospheric Mantle Peridotites in the Westernmost Mediterranean

    Science.gov (United States)

    Garrido, Carlos J.; Hidas, Károly; Marchesi, Claudio; Varas-Reus, María Isabel; Booth-Rea, Guillermo

    2017-04-01

    Exhumation of subcontinental mantle peridotite in the Western Mediterranean has been attributed to different tectonic processes including pure extension, transpression, or alternating contractive and extensional processes related with continental subduction followed by extension, before final their contractive intracrustal emplacement. Any model trying to explain the exhumation and emplacement of subcontinental lithospheric mantle peridotites in the westernmost Mediterranean should take into account the available geochronological constraints, as well as the petrological and geochemical processes that lead to internal tectono-magmatic zoning so characteristic of the Betic and Rif orogenic peridotites. Different studies have suggested a Hercynian, Cenozoic-Mesozoic or an Alpine age for the late tectono-magmatic evolution and intra-crustal emplacement of Betic-Rif peridotites. The pervasive presence of Mesozoic U-Pb zircon ages in Ronda UHP and HP garnet pyroxenites does not support a Hercynian age for the intracrustal emplacement of the peridotite. A hyper-extended margin setting for is in good agreement with the Jurassic extensional event that pervasively affected ALKAPECA terrains (i.e. the Alboran, Kabylides, Peloritani, and Calabria domains) in the western Mediterranean due to the opening of the Piemonte-Ligurian Ocean. However, a Jurassic age and a passive margin tectonic setting do not account, among other observations, for the late Miocene thermochronological ages recorded in zircons rims (U-Pb) and garnets (Lu-Hf) in garnet pyroxenites from the Betic-Rif peridotites, the pervasive Miocene resetting of U-Pb zircon and monazite ages in the overlying Jubrique crustal section, the supra-subduction radiogenic signature of late pyroxenite intrusive dikes in the Ronda peridotite, and the arc tholeiitic affinity of late mantle-derived, gabbroic dykes intruding in the Ronda and Ojen plagioclase lherzolites. These data are more consistent with a supra

  17. Geology and tectonic magmatic of emplacement of a longitudinal dyke swarm of Nico Perez(Minas) URUGUAY

    International Nuclear Information System (INIS)

    Gonzalez, P.; Poire, D.; Canalicchio, J.; Garcia Repetto, F.

    2004-01-01

    The Mina Verdun Group (Precambrian) was deposited prior to the subvolcanic emplacement of a longitudinal dyke swarm of basaltic to andesitic composition (Minas Subvolcanic Swarm of the Mina Verdun quarry - Nico Perez Terrane, Minas, Uruguay). The swarm and its country rocks predated a tectono-metamorphic event that produced fragileductile shear zones associated with very low- to low-grade dislocation metamorphism. We interpreted a K-Ar whole rock datum of 485,2 ± 12,5 Ma (andesitic dyke) as a minimum cooling age in relation with late- to post-swarm emplacement deuteric alteration stage. Another K-Ar whole rock datum of 108,5 ± 2,9 Ma on a basaltic dyke was assumed here as a degasification stage, while its geological meaning is still matter of debate. The Minas Subvolcanic Dyke Swarm was intruded at high crustal levels, suggesting that the Minas region was affected by a period of extensional tectonics [es

  18. Electrical structure of the lithosphere across the Western Paraná suture zone: the role of a Neoproterozoic-Cambrian subduction in generating the Paraná Magmatic Province

    Science.gov (United States)

    Dragone, G. N.; Bologna, M.; Gimenez, M. E.; Alvarez, O.; Lince Klinger, F. G.; Correa-Otto, S.; Ussami, N.

    2017-12-01

    The Paraná Magmatic Province (PMP) together with the Etendeka Province (EP) in Africa is one of the Earth's largest igneous provinces originated prior to the Western Gondwanaland break-up and the inception of the South Atlantic Ocean in the Lower Cretaceous. Geochemical data of PMP-EP basalts collected since late 1980's indicate the origin of PMP-EP by melting of a heterogeneous and enriched subcontinental lithospheric mantle with fast rate of eruption (borders of the PMP, the Western Paraná suture zone (WPS in Fig. 1). We discuss the electrical properties of the lithosphere along three MT profiles across the WPS. MT-A profile (Padilha et al., 2015, JGR) extends from Rio Apa craton towards the center of PMP (high-TiO2 basalts). Profile MT-B extends from Tebicuary craton towards the center of PMP (low-TiO2) and profile MT-C extends from Rio de la Plata craton towards the southern PMP (low- and high-TiO2). All profiles show a resistive ( 104 ohm m) and thick (> 150 km) lithosphere in the cratonic areas whereas the electrical lithosphere is thinner (<100 km) with alternating high and low resistivities within PMP. Vertically elongated and high electrical conductivity anomalies ( 10 ohm m) centered at 40 km depth occur along the -30 mGal contour line in the three profiles, and are interpreted as the location of the suture and former subduction zone. We will discuss the correlation between geochemical and petrological characteristics of basalts and the electrical properties of the lithospheric mantle underneath.

  19. Paleomagnetism of Siberian Trap Intrusions: Implications for the Timing and Intensity of the Magmatic Activity

    Science.gov (United States)

    Latyshev, Anton; Veselovskiy, Roman; Mirsayanova, Elina; Ulyahina, Polina

    2016-04-01

    Large Igneous Provinces (LIPs) are the areas of the exceptional interest due to associated Cu-Ni-Pt deposits, problems of the causal link between volcanic hazards and mass extinctions, and questions about mantle plume dynamics. High-precise U-Pb and 40Ar/39Ar dating determined the duration of the main phase of the most voluminous Siberian Trap province formation as 1-2 Ma (Kamo et al., 2003; Reichow et al., 2008). Recent paleomagnetic investigations demonstrated the predominance of pulsating volcanic activity during LIPs formation (Chenet et al., 2009; Pavlov et al., 2015). We perform the results of detailed paleomagnetic study of intrusive complexes from Tunguska syncline and Angara-Taseeva depression (Siberian Trap province). Our data taken together with the previous paleomagnetic results from trap intrusions revealed two different styles of magmatic activity. In the central part of Tunguska syncline emplacement of was rather even without sharp bursts. Local intrusive events coeval to volcanic eruptions took place within spatially limited areas. In contrast, in the periphery of Tunguska syncline several short and powerful peaks of magmatic activity happened on the background of weak prolonged magmatism. These events resulted in huge Padunsky, Tulunsky and some other sills in the southern part of the Siberian platform. According to our paleomagnetic data, the duration of such pulses did not exceed 10-100 thousand years. Taking into account our paleomagnetic data and recent U-Pb ages for Siberian trap intrusions from (Burgess, Bowring, 2015), it is possible to correlate intrusive complexes with the volcanic section. In particular, formation the largest Tulunsky and Padunsky sills happened right after the termination of the main phase of Permian-Triassic volcanic activity on the Siberian platform. This work was supported by grants RFBR # 16-35-60114 and 15-35-20599 and Ministry of Education and Science of the Russian Federation (grant 14.Z50.31.0017).

  20. Geology, petrography and geochemistry of the A-type granites from the Morro Redondo Complex (PR-SC, southern Brazil, Graciosa Province

    Directory of Open Access Journals (Sweden)

    FREDERICO C.J. VILALVA

    2014-03-01

    Full Text Available The Morro Redondo Complex is one of the most important occurrences of the Graciosa A-type Province, southern Brazil. It consists of the Papanduva and Quiriri granitic plutons and a contemporaneous bimodal volcanic association. The Papanduva Pluton includes massive and deformed peralkaline alkali-feldspar granites with Na-Ca and Na-amphiboles and clinopyroxenes. The deformed types are the most evolved rocks in the province and carry rare ‘agpaitic’ minerals, some being described for the first time in granites from Brazil. The larger Quiriri Pluton comprises massive, slightly peraluminous, biotite syeno- and monzogranites with rare Ca-amphibole. Biotite compositions are relatively homogeneous, whereas sodic amphiboles and clinopyroxenes show increasing Na and Fe3+ evolving paths. The Morro Redondo granites are ferroan, with high SiO2, alkalis and HFSE contents; the peralkaline types registering the highest fe#. LILE and HFSE abundances increase with the agpaitic index and the most evolved are HHP granites, with radiogenic heat production up to 5.7 µWm–3. Geothermobarometric estimates indicate emplacement under low pressures (∼100 MPa, at temperatures up to 850-800 °C, and relatively reduced (QFM and oxidized (+1 REPLACE_LT ΔQFM REPLACE_LT +3 environments for the Papanduva and Quiriri Plutons, respectively. In both cases, melts evolved to relatively high oxidation states upon crystallization progress.

  1. Granitoid emplacement during syn-convergent transtension: An example from the Huamenlou pluton in North Qinling, central China

    Directory of Open Access Journals (Sweden)

    Yang Li

    2018-01-01

    Full Text Available The Huamenlou pluton, is an elongated granite intrusion with high aspect ratio, emplaced within the southern margin of the North Qinling (central China. Here we investigate this pluton through multiple techniques including the fabric study, microstructural observation and zircon geochronology. Our zircon U–Pb data confirm that the granite crystallized at ca. 462 Ma which is consistent with the ages of other linear plutons in North Qinling. Microstructural observations of the Huamenlou granites illustrate that the pluton has undergone superimposed deformation during its emplacement, from magmatic to high-temperature solid state conditions. The internal fabric obtained by anisotropy of magnetic susceptibility (AMS and shape preferred orientation (SPO show similar results. The fabrics are relatively concordant and generally vary from NE–SW to NEE–SWW which are roughly oblique to the trend of the pluton elongation and the regional structures. Meanwhile, scalar parameters reflect two completely different strain regimes for the pluton and its host rocks, i.e., the fabrics within host rocks are mainly oblate while the central part of the intrusion displays mainly prolate fabrics. It is inferred that the structural pattern recorded in this pluton was caused by local dextral transtension in consequence of oblique convergence between the South and North China Blocks. We propose that the local transtension in convergence setting probably evolved from vertical extrusion tectonics that provided room for the magma emplacement and imparted prolate fabrics in the Huamenlou pluton.

  2. Journal of Earth System Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Low-Ti melts from the southeastern Siberian Traps Large Igneous Province: ... ash in the Quaternary alluvial deposits, lower Narmada basin, western India .... Impact of aerosols from the Asian Continent on the adjoining oceanic environments.

  3. Using Tellus data to enhance targeting of volcanogenic massive sulphide mineralisation in the Tyrone Igneous Complex

    OpenAIRE

    Hollis, Steven; Cooper, Mark; Earls, Garth; Roberts, Stephen; Herrington, Richard; Piercey, Stephen

    2016-01-01

    The Tyrone Igneous Complex of Northern Ireland has been a target for base and precious metal exploration since the 1970s. Historic exploration was hampered by poor exposure and consequently a limited understanding of the local geology. Extensive new field mapping, utilising the high-resolution Tellus geophysical survey, coupled with U-Pb zircon geochronology and whole-rock geochemistry, has greatly improved our understanding of the complex and its potential to host volcanogenic massive sulphi...

  4. Fluid-present melting of meta-igneous rocks and the generation of leucogranites – Constraints from garnet major and trace element data, Lu-Hf whole rock-garnet ages and whole rock Nd-Sr-Hf-O isotope data

    NARCIS (Netherlands)

    Jung, C.; Jung, S.; Nebel, O.; Hellebrand, E.; Masberg, P.; Hoffer, E.

    2009-01-01

    Pan-African high-grade metamorphism in the Proterozoic Damara orogen (Namibia) led to formation of garnet-bearing leucosomes in potassic meta-igneous gneisses producing a meta-igneous migmatite. In addition, the migmatite (gneiss (mesosome) plus leucosome) was intruded by small-scale leucogranitic

  5. Lithofacies of deep marine basalts emplaced on a Jurassic backarc apron, Baja California (Mexico)

    Energy Technology Data Exchange (ETDEWEB)

    Busby-Spera, C.J.

    1987-09-01

    Basalts of the mid-Jurassic Gran Canon Formation, Cedros Island, Mexico, were emplaced on a volcaniclastic apron in a deep marine backarc basin. Elongate pillows and lava tubes, as well as paleocurrent data from the volcaniclastic apron, indicate a southward regional paleoslope away from the island arc source. Basalts emplaced on relatively proximal parts of the apron are nearly entirely pillowed and have thick flow units with mega-pillows. Basalts on distal parts of the apron (about 15 to 20 km down paleo-current) are dominated by pillow fragment breccias (flow foot rubble), and individual lava flows are generally thin, with small pillows, suggesting that the distal ends of lava flows, erupted upslope, are represented. These distal flow fronts, however, are interstratified with features that typically form close to a vent, including thick massive to mega-pillowed lavas and lava tubes up to 8 m in diameter. It is inferred that a fissure (or system of fissures) extended from the arc into the backarc basin, erupting basalt lavas onto both proximal and distal parts of the volcaniclastic apron. Such intraplate volcanism may be common on the hot frontal arc side of backarc basins. 26 references.

  6. Granitic magma emplacement and deformation during early-orogenic syn-convergent transtension: The Stare Sedlo complex, Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Tomek, Filip; Žák, J.; Chadima, Martin

    2015-01-01

    Roč. 87, JUL (2015), s. 50-66 ISSN 0264-3707 Institutional support: RVO:67985831 Keywords : anisotropy of magnetic susceptibility (AMS) * Bohemian Massif * pluton emplacement * granite * transtension * Variscan orogeny Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.926, year: 2015

  7. U-Pb ages and geochemistry of zircon from Proterozoic plutons of the Sawatch and Mosquito ranges, Colorado, U.S.A.: Implications for crustal growth of the central Colorado province

    Science.gov (United States)

    Moscati, Richard J.; Premo, Wayne R.; Dewitt, Ed; Wooden, Joseph L.

    2017-01-01

    A broad study of zircons from plutonic rocks of the Sawatch and Mosquito ranges of west-central Colorado (U.S.A.) was undertaken to significantly refine the magmatic chronology and chemistry of this under-studied region of the Colorado province. This region was chosen because it lies just to the north of the suspected arc-related Gunnison-Salida volcano-plutonic terrane, which has been the subject of many recent investigations—and whose origin is still debated. Our new results provide important insights into the processes active during Proterozoic crustal evolution in this region, and they have important ramifications for broader-scope crustal evolution models for southwestern North America.Twenty-four new U-Pb ages and sequentially acquired rare-earth element (REE), U, Th, and Hf contents of zircon have been determined using the sensitive high-resolution ion microprobe-reverse geometry (SHRIMP-RG). These zircon geochemistry data, in conjunction with whole-rock major- and trace-element data, provide important insights into zircon crystallization and melt fractionation, and they help to further constrain the tectonic environment of magma generation.Our detailed zircon and whole-rock data support the following three interpretations:(1) The Roosevelt Granite in the southern Sawatch Range was the oldest rock dated at 1,766 ± 7 Ma, and it intruded various metavolcanic and metasedimentary rocks. Geochemistry of both whole-rock and zircon supports the contention that this granite was produced in a magmatic arc environment and, therefore, is likely an extension of the older Dubois Greenstone Belt of the Gunnison Igneous Complex (GIC) and the Needle Mountains (1,770–1,755 Ma). Rocks of the younger Cochetopa succession of the GIC, the Salida Greenstone Belt, and the Sangre de Cristo Mountains (1,740–1,725 Ma) were not found in the Sawatch and Mosquito ranges. This observation strongly suggests that the northern edge of the Gunnison-Salida arc terrane underlies the

  8. Thermal modeling of pluton emplacement and associated contact metamorphism:Parashi stock emplacement in the Serranía de Jarara (Alta Guajira, Colombia

    Directory of Open Access Journals (Sweden)

    Zuluaga C. Carlos A.

    2010-12-01

    Full Text Available

    In the northernmost portion of the Serrania de Jarara (Alta Guajira, Colombia, low - medium grade metamorphic rocks from the Etpana Metamorphic Suite were thermally affected by emplacement of a small calc-alkaline intrusion (Parashi Stock. Detailed petrographic analysis in collected rock samples across the NE and NW plutonic contacts show occurrences of textural and mineralogical changes in the country rock fabric that evidence contact metamorphism overprinting regional metamorphism of the Etpana Suite. These changes include growth of andalusite (chiastolite, calcic clinopyroxeneand amphibole porphyroblast crosscutting Sn+1 metamorphicfoliation. Hornblende-plagioclase barometry (ca. 3.1 kbar and cooling models for the stock show maximum time temperature evolution in the country rock at the interpreted depth of intrusion (ca. 11 km and help to evaluate the behavior of the country rock with the changing local geotherm.

  9. Monte-Carlo based comparison of the personal dose for emplacement scenarios of spent nuclear fuel casks in generic deep geological repositories

    Energy Technology Data Exchange (ETDEWEB)

    Suarez, Hector Sauri; Becker, Franz; Metz, Volker [Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen (Germany). Inst. for Nuclear Waste Disposal (INE); Pang, Bo [Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen (Germany). Inst. for Nuclear Waste Disposal (INE); Shenzhen Univ. (China). College of Physics and Energy

    2017-06-15

    In the operational phase of a deep geological disposal facility for high-level nuclear waste, the radiation field in the vicinity of a waste cask is influenced by the backscattered radiation of the surrounding walls of the emplacement drift. For a comparison of disposal of spent nuclear fuel in various host rocks, it is of interest to investigate the influence of the surrounding materials on the radiation field and the personal radiation exposure. In this generic study individual dosimetry of personnel involved in emplacement of casks with spent nuclear fuel in drifts in rock salt and in a clay formation was modelled.

  10. U-Pb baddeleyite ages and geochemistry of dolerite dykes in the Bas Drâa Inlier of the Anti-Atlas of Morocco: Newly identified 1380 Ma event in the West African Craton

    Science.gov (United States)

    El Bahat, Abdelhakim; Ikenne, Moha; Söderlund, Ulf; Cousens, Brian; Youbi, Nasrrddine; Ernst, Richard; Soulaimani, Abderrahmane; El Janati, M'hamed; Hafid, Ahmid

    2013-08-01

    In the Bas-Drâa Inlier (Anti-Atlas, Morocco), the Paleoproterozoic basement which is cut by the Ediacaran Taourgha granite is also crosscut by numerous dykes of a variety of trends, mostly of uncertain age. Two doleritic dykes are dated by the ID-TIMS U-Pb method on baddeleyite and yield emplacement ages of 1381 ± 8 Ma (MSWD = 0.84) and 1384 ± 6 Ma (MSWD = 1.4) determined for a N135°E and a N40°E trending dyke, respectively. These dates represent the first geochronological evidence of a Mesoproterozoic magmatic event in the Anti-Atlas. This magmatic event falls in the previously considered ca 1.7-1.0 Ga (Mesoproterozoic) gap in geological activity in the Anti-Atlas. The poorly dated Taghdout and Taarotihate sequences could represent remnants of the ca. 1380 Ma magmatism and rift-related sedimentation. The Mesoproterozoic sedimentary succession of the Atar Group in the Taoudeni basin (Mauritania) could also represent a good candidate for rift-related sedimentation but it postdates the 1380 Ma magmatic event by 270 Ma. The dated 1380 Ma dykes are transitional to mildly alkaline basalts, not unlike some Hawaiian lavas. However, these dykes have a distinct negative Nb anomaly (a common features in many Large Igneous Provinces, LIPs), and this requires interaction with the lithosphere. This interaction may have occurred at the level of the lithospheric mantle or the crust. These newly dated 1380 Ma dykes may converge to the north, speculatively suggesting a magmatic center (associated with a 1380 Ma mantle plume?) along the northern margin, and possibly linked to rifting and possible breakup on that margin, and also to a regional uplift that largely removed the evidence of a 1380 Ma cover sequence. Contemporaneous 1380-1390 Ma magmatism is reported elsewhere on other crustal blocks, and that in northeastern Laurentia (northern Greenland), northern Siberia (Anabar shield), and Baltica (southern Urals) can be reconstructed with that of the Bas Drâa Inlier (Anti

  11. Subduction initiation, recycling of Alboran lower crust, and intracrustal emplacement of subcontinental lithospheric mantle in the Westernmost Mediterranean

    Science.gov (United States)

    Varas-Reus, María Isabel; Garrido, Carlos J.; Bosch, Delphine; Marchesi, Claudio; Hidas, Károly; Booth-Rea, Guillermo; Acosta-Vigil, Antonio

    2015-04-01

    Unraveling the tectonic settings and processes involved in the annihilation of subcontinental mantle lithosphere is of paramount importance for our understanding of the endurance of continents through Earth history. Unlike ophiolites -- their oceanic mantle lithosphere counterparts -- the mechanisms of emplacement of the subcontinental mantle lithosphere in orogens is still poorly known. The emplacement of subcontinental lithospheric mantle peridotites is often attributed to extension in rifted passive margins or continental backarc basins, accretionary processes in subduction zones, or some combination of these processes. One of the most prominent features of the westernmost Mediterranean Alpine orogenic arcs is the presence of the largest outcrops worldwide of diamond facies, subcontinental mantle peridotite massifs; unveiling the mechanisms of emplacement of these massifs may provide important clues on processes involved in the destruction of continents. The western Mediterranean underwent a complex Alpine evolution of subduction initiation, slab fragmentation, and rollback within a context of slow convergence of Africa and Europe In the westernmost Mediterranean, the alpine orogeny ends in the Gibraltar tight arc, which is bounded by the Betic, Rif and Tell belts that surround the Alboran and Algero-Balearic basins. The internal units of these belts are mostly constituted of an allochthonous lithospheric domain that collided and overthrusted Mesozoic and Tertiary sedimentary rocks of the Mesozoic-Paleogene, South Iberian and Maghrebian rifted continental paleomargins. Subcontinental lithospheric peridotite massifs are intercalated between polymetamorphic internal units of the Betic (Ronda, Ojen and Carratraca massifs), Rif (Beni Bousera), and Tell belts. In the Betic chain, the internal zones of the allochthonous Alboran domain include, from bottom to top, polymetamorphic rock of the Alpujarride and Malaguide complexes. The Ronda peridotite massif -- the

  12. Simultaneous measurement of thermal conductivity, thermal diffusivity and prediction of effective thermal conductivity of porous consolidated igneous rocks at room temperature

    International Nuclear Information System (INIS)

    Aurangzeb; Ali, Zulqurnain; Gurmani, Samia Faiz; Maqsood, Asghari

    2006-01-01

    Thermal conductivity, thermal diffusivity and heat capacity per unit volume of porous consolidated igneous rocks have been measured, simultaneously by Gustafsson's probe at room temperature and normal pressure using air as saturant. Data are presented for eleven samples of dunite, ranging in porosity from 0.130 to 0.665% by volume, taken from Chillas near Gilgit, Pakistan. The porosity and density parameters have been measured using American Society of Testing and Materials (ASTM) standards at ambient conditions. The mineral composition of samples has been analysed from their thin sections (petrography). An empirical model to predict the thermal conductivity of porous consolidated igneous rocks is also proposed. The thermal conductivities are predicted by some of the existing models along with the proposed one. It is observed that the values of effective thermal conductivity predicted by the proposed model are in agreement with the experimental thermal conductivity data within 6%

  13. Pluton emplacement in a releasing bend in a transpressive regime: the arrozal granite in the Paraíba do Sul shear belt, Rio de Janeiro.

    Science.gov (United States)

    Nummer, Alexis R; Machado, Rômulo; Dehler, Nolan M

    2007-06-01

    The Arrozal Granite, situated in the southwestern region of the State of Rio de Janeiro, has a granitic to granodioritic composition. It contains a strong mylonitic foliation along its border, passing gradually to a well-developed magmatic foliation towards its center. Structural analysis indicates that the Arrozal Granite was emplaced along the Além-Paraíba Shear Zone in a dextral transpressive tectonic regime. A regional shift of the trend along this shear zone from NE-SW to E-W, observed in the area, is interpreted to be casually related to the creation of space for the emplacement of the granite. Our data indicate that releasing bends may have played an important role for space generation during the emplacement of the Arrozal Granite and other plutons.

  14. The Summer 1997 Eruption at Pillan Patera on Io: Implications for Ultrabasic Lava Flow Emplacement

    Science.gov (United States)

    Williams, David A.; Davies, Ashley G.; Keszthelyi, Laszlo P.; Greeley, Ronald

    2001-01-01

    Galileo data and numerical modeling were used to investigate the summer 1977 eruption at Pillan Patera on Io. This event, now defined as "Pillanian" eruption style, included a high-temperature (greater than 1600 C), possible ultrabasic , 140-km-high plume eruption that deposited dark, orthopyroxene-rich pyroclastic material over greater than 125,000 sq km, followed by emplacement of dark flow-like material over greater than 3100 sq km to the north of the caldera. We estimate that the high-temperature, energetic episode of this eruption had a duration of 52 - 167 days between May and September 1997, with peak eruption temperatures around June 28, 1997. Galileo 20 m/pixel images of part of the Pillan flow field show a wide-spread, rough, pitted surface that is unlike any flow surface we have seen before. We suggest that this surface may have resulted from: 1. A fractured lava crust formed during rapid, low-viscosity lava surging, perhaps including turbulent flow emplacement. 2. Disruption of the lava flow by explosive interaction with a volatile-rich substrate. or 3. A combination of 1 and 2 with or without accumulation of pyroclastic material on the surface. Well-developed flow lobes are observed, suggesting that this is a relatively distant part of the flow field.Shadow measurements at flow margins indicate a thickness of-8 - 10 m. We have modeled the emplacement of putative ultrabasic flow from the summer 1997 Pillan eruption using constraints from new Galileo data. Results suggest that either laminar sheet flows or turbulent channelized flows could have traveled 50 - 150 km on a flat, unobstructed surface, which is consistent with the estimated length of the Pillan flow field (approx. 60 km). Our modeling suggests low thermal erosion rates (less than 4.1 m/d), and that the formation of deep (greater than 20 m) erosion channels was unlikely, especially distal to the source. We calculate a volumetric flow rate of approx. 2 - 7 x 10(exp 3)cu m/s, which is greater

  15. Wind potential assessment of Quebec Province

    International Nuclear Information System (INIS)

    Ilinca, A.; Chaumel, J.-L.; Retiveau, J.-L.

    2003-01-01

    The paper presents the development of a comprehensive wind atlas of the Province of Quebec. This study differs from previous studies by 1) use of a standard classification index to categorize the wind resource, 2) extensive review of surface and upper air data available for the Province to define the wind resource, and 3) integration of available wind data with the topography of the Province. The wind resource in the Province of Quebec is classified using the scheme proposed by Battelle-Pacific Northwest Laboratory (PNL). The Battelle-PNL classification is a numerical one which includes rankings from Wind Power Class 1 (lowest) to Wind Power Class 7 (highest). Associated with each numerical classification is a range of wind power and associated mean wind speed at 10 m and 50 m above ground level. For this study, a classification for 30 m above ground level was interpolated and used. A significant amount of wind data was gathered for the Province. These data were obtained from Atmospheric Environment Service (AES), Canada, from wind project developers, and from climatological summaries of surface and upper air data. A total of 35 primary data sites were selected in the Province. Although a number of wind data sites in the Province were identified and used in the analysis, large areas of the Province lacked any specific wind information. The Province was divided into grid blocks having dimensions of 1/4 o latitude by 1/3 o longitude. Each grid block is assigned a numerical Wind Power Class value ranging from 1 to 7. This value is based on the integration of the available wind data and the topography within the square. The majority of the Province was classified as 1 or 2. Coastal locations and topographic features in the interior of the Province typically have Wind Power Class 3 or higher. (author)

  16. The Triassic-Liassic volcanic sequence and rift evolution in the Saharan Atlas basins (Algeria). Eastward vanishing of the Central Atlantic magmatic province

    Energy Technology Data Exchange (ETDEWEB)

    Meddah, A.; Bertrand, H.; Seddiki, A.; Tabeliouna, M.

    2017-11-01

    We investigate the Triassic-Liassic sequence in ten diapirs from the Saharan Atlas (Algeria). Based on detailed mapping, two episodes are identified. The first one consists of a volcano-sedimentary sequence in which three volcanic units were identified (lower, intermediate and upper units). They are interlayered and sometimes imbricated with siliciclastic to evaporitic levels which record syn-sedimentary tectonics. This sequence was deposited in a lagoonal-continental environment and is assigned to the Triassic magmatic rifting stage. The second episode, lacking lava flows (post magmatic rifting stage), consists of carbonate levels deposited in a lagoonal to marine environment during the Rhaetian-Hettangian. The volcanic units consist of several thin basaltic flows, each 0.5 to 1m thick, with a total thickness of 10–15m. The basalts are low-Ti continental tholeiites, displaying enrichment in large ion lithophile elements and light rare earth elements [(La/Yb)n= 2.5-6] with a negative Nb anomaly. Upwards decrease of light-rare-earth-elements enrichment (e.g. La/Yb) is modelled through increasing melting rate of a spinel-bearing lherzolite source from the lower (6–10wt.%) to the upper (15–20wt.%) unit. The lava flows from the Saharan Atlas share the same geochemical characteristics and evolution as those from the Moroccan Atlas assigned to the Central Atlantic magmatic province. They represent the easternmost witness of this large igneous province so far known.

  17. The Triassic-Liassic volcanic sequence and rift evolution in the Saharan Atlas basins (Algeria). Eastward vanishing of the Central Atlantic magmatic province

    International Nuclear Information System (INIS)

    Meddah, A.; Bertrand, H.; Seddiki, A.; Tabeliouna, M.

    2017-01-01

    We investigate the Triassic-Liassic sequence in ten diapirs from the Saharan Atlas (Algeria). Based on detailed mapping, two episodes are identified. The first one consists of a volcano-sedimentary sequence in which three volcanic units were identified (lower, intermediate and upper units). They are interlayered and sometimes imbricated with siliciclastic to evaporitic levels which record syn-sedimentary tectonics. This sequence was deposited in a lagoonal-continental environment and is assigned to the Triassic magmatic rifting stage. The second episode, lacking lava flows (post magmatic rifting stage), consists of carbonate levels deposited in a lagoonal to marine environment during the Rhaetian-Hettangian. The volcanic units consist of several thin basaltic flows, each 0.5 to 1m thick, with a total thickness of 10–15m. The basalts are low-Ti continental tholeiites, displaying enrichment in large ion lithophile elements and light rare earth elements [(La/Yb)n= 2.5-6] with a negative Nb anomaly. Upwards decrease of light-rare-earth-elements enrichment (e.g. La/Yb) is modelled through increasing melting rate of a spinel-bearing lherzolite source from the lower (6–10wt.%) to the upper (15–20wt.%) unit. The lava flows from the Saharan Atlas share the same geochemical characteristics and evolution as those from the Moroccan Atlas assigned to the Central Atlantic magmatic province. They represent the easternmost witness of this large igneous province so far known.

  18. Waste package transfer, emplacement and retrievability in the French deep geological repository

    Energy Technology Data Exchange (ETDEWEB)

    Roulet, Alain; Delort, Daniel; Herve, Jean Francois; Bosgiraud, Jean Michel; Guenin, Jean Jacques [Technical Department ANDRA (France)

    2009-06-15

    Safe, reliable and reversible handling of waste is a significant issue related to the design and safety assessment of deep geological repository in France. The first step taken was to study various waste handling solutions. ANDRA also decided to fabricate and demonstrate industrial scale handling equipment for HLW (since 2003) and for ILW-LL wastes (since 2008). We will review the main equipment developed for the transfer process in the repository, for both types of waste, and underline the benefits of developing industrial demonstrators within the framework of international cooperation agreements. Waste retrieval capability will be simultaneously examined. Two types of waste have to be handled underground in Andra's repository. The HLW disposal package for vitrified waste is a 2 ton carbon steel cylindrical canister with a diameter of 600 mm. The weight of ILW-LL concrete disposal packages range from a minimum of 6 tonnes to over 20 tonnes, and their volume from approximately 5 to 10 m3. The underground transfer to the disposal drift requires moving the disposal package within a shielded transfer cask placed on a trailer. Transfer cask design has evolved since 2005, due to optimisation studies and as a result of industrial feedback from SKB. For HLW handling equipment two design options have been studied. In the first solution (Andra's Dossier 2005), the waste package are emplaced, one at a time, in the disposal drift by a pushing robot. Successive steps in design and proto-typing have lead to improve the design of the equipment and to gain confidence. Recently a fully integrated process has been successfully demonstrated, at full scale, (in a 100 m long mock up drift) as part of the EC funded ESDRED Project. This demonstrator is now on display in Andra's Technology Centre at Saudron, near the Bure Underground Laboratory. The second disposal option which has been investigated is based on a concept of utilising an external apparatus to push a row of

  19. Hazard and consequence analysis for waste emplacement at the Waste Isolation Pilot Plant

    International Nuclear Information System (INIS)

    Gerstner, D.M.; Clayton, S.G.; Farrell, R.F.; McCormick, J.A.; Ortiz, C.; Standiford, D.L.

    1996-01-01

    The Carlsbad Area Office established and analyzed the safety bases for the design and operations as documented in the WIPP Safety Analysis Report (SAR). Additional independent efforts are currently underway to assess the hazards associated with the long-term (10,000 year) isolation period as required by 40 CFR 191. The structure of the WIPP SAR is unique due to the hazards involved, and the agreement between the State of New Mexico and the DOE regarding SAR content and format. However, the hazards and accident analysis philosophy as contained in DOE-STD-3009-94 was followed as closely as possible, while adhering to state agreements. Hazards associated with WIPP waste receipt, emplacement, and disposal operations were systematically identified using a modified Hazard and Operability Study (HAZOP) technique. The WIPP HAZOP assessed the potential internal, external, and natural phenomena events that can cause the identified hazards to develop into accidents. The hazard assessment identified deviations from the intended design and operation of the waste handling system, analyzed potential accident consequences to the public and workers, estimated likelihood of occurrence, and evaluated associated preventative and mitigative features. It was concluded from the assessment that the proposed WIPP waste emplacement operations and design are sufficient to ensure safety of the public, workers, and environment, over the 35 year disposal phase

  20. Emplacement dynamics and lava field evolution of the flood basalt eruption at Holuhraun, Iceland: Observations from field and remote sensing data

    Science.gov (United States)

    Pedersen, Gro; Höskuldsson, Armann; Riishuus, Morten S.; Jónsdóttir, Ingibjörg; Thórdarson, Thorvaldur; Dürig, Tobias; Gudmundsson, Magnus T.; Durmont, Stephanie

    2016-04-01

    The Holuhraun eruption (Aug 2014- Feb 2015) is the largest effusive eruption in Iceland since the Laki eruption in 1783-84, with an estimated lava volume of ~1.6 km3 covering an area of ~83 km2. The eruption provides an unprecedented opportunity to study i) lava morphologies and their emplacement styles, ii) Morphological transitions iii) the transition from open to closed lava pathways and iv) the implication of lava pond formation. This study is based on three different categories of data; field data, airborne data and satellite data. The field data include tracking of the lava advancement by Global Positioning System (GPS) measurements and georeferenced GoPro cameras allowing classification of the lava margin morphology. Furthermore, video footage on-site documented lava emplacement. Complimentary observations have been provided from aircraft platforms and by satellite data. Of particular importance for lava morphology observations are 1-12 m/pixel airborne Synthetic Aperture Radar (SAR) images (x-band), as well as SAR data from TerraSAR-X and COSMO-SkyMed satellites. The Holuhraun lava field comprises a continuum of morphologies from pāhoehoe to 'a'ā, which have varied temporally and spatially. Shelly pāhoehoe lava was the first morphology to be observed (08-29). Spatially, this lava type was not widely distributed, but was emplaced throughout the eruption close to the vent area and the lava channels. Slabby pāhoehoe lava was initially observed the 08-31 and was observed throughout most of the eruption during the high-lava-flux phase of new lava lobe emplacement. 'A'ā lavas were the dominating morphology the first three months of the eruption and was first observed 09-01 like Rubbly pāhoehoe lava. Finally, Spiny pāhoehoe lava was first observed the 09-05 as a few marginal outbreaks along the fairly inactive parts of the 'a'ā lava lobe. However, throughout the eruption this morphology became more important and from mid-November/beginning of December the

  1. Genesis of Soils Formed from Mafic Igneous Rock in the Atlantic Forest Environment

    Directory of Open Access Journals (Sweden)

    Adailde do Carmo Santos

    2016-01-01

    Full Text Available ABSTRACT Different parent materials participate in the formation of soils in the hilly landscape of “Mar de Morros” in the Atlantic Forest environment. Those derived from mafic igneous rock (gabbro frequently show erosion problems because of land use, which is aggravated by the mountainous relief and soil attributes. This study evaluated the main pedogenic processes of soils formed from mafic igneous rock (gabbro in a toposequence in Pinheiral (RJ by characterizing physical, chemical, mineralogical and micromorphological attributes. The profiles are located at different sections in the toposequence: summit (P1, shoulder (P2, backslope (P3 and footslope (P4.They were classified according to the Brazilian System of Soil Classification (SiBCS and correlated to Soil Taxonomy. The soil morphology of profiles P2, P3 and P4 is expressed by a brownish-red color, blocky structure with high to moderate development, clay films and clay loam to clay texture, with a textural B horizon. P1 shows less development, with a shallow profile and the sequence of horizons A-C-Cr. The soils have a slightly low degree of weathering, identified by the presence of pyroxenes and feldspars in the sand fraction and montorillonite in the clay fraction; the sum of bases is from 15 to 24 cmolc kg-1; and cation exchange capacity (CEC is from 12 to 22 cmolc kg-1. A significant presence of clay skins was observed in the field and was confirmed by thin section analysis, which showed features such as argillans, ferriargillans and iron nodules. The soil profile at the summit (P1 was classified as Neossolo Regolítico Órtico (Typic Udorthents, and the other profiles as Chernossolo Argilúvicos Órticos (Typic Argiudolls.

  2. Geochemistry of Late Mesozoic mafic dykes in western Fujian Province of China:Sr-Nd isotope and trace element constraints

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Bancun diabase dyke and the Bali hornblende gabbro dyke in western Fuiian Province were emplaced in the Early and Late Cretaceous periods,respectively;the former is designated to calc-alkaline series and the latter to K-high-calc-alkaline rock series.Both the dykes are characterized by such geochemical characteristics as high Al and Na2O>K2O.As for the Bancun dyke,A12O3=16.32%-17.54%and K2O/Na2O=0.65-0.77;as for the Bali dyke,A12O3=16.89%-17.81%and K2O,Na2O=O.93-O.99.Both the Bancun and Bali mafic dykes are relatively endched in LILE and LREE,but depleted in HSFE, displaying the geochemical characteristics of continental marginal arc,with high initial Sr isotopic ratios and low εNd values,The (87Sr/86Sr)i ratios of the Bancun diabase dyke are within the range of 0.708556-0.70903 and their εNd(t)values vary between-6.8 and-6.3;those of the Bali hornblende dyke are within the range of 0.708556-0.710746 and their εNd(t) values are -4.7--4.7,showing the characteristics of enriched mantle EM Ⅱ.The isotope and trace element data showed that the mafic dykes have not experienced obvious crustal contamination,and metasomatism caused by subduction fluids is the main factor leading to LILE and UREE enrichments.The enriched mantle is the source region for the mafic dykes,and mixing of subduction fluid metasomatized enriched mantle and EM Ⅱ-type mantle constituted the mantle source region of both the Bancun and Bali mafic dykes.Upwelling of the asthenosphere mantle provided sufficient heat energy for the generation of magmas.In accordance with the discrimination diagram of their tectonic settings as well as their trace element geochemical characteristics,it is considered that the dykes both at Bancun and Bali possess the characteristics of continental marginal arc,revealing the tectonic environment of formation of the mafic dykes,the continental dynamic background as an intraplate tensional belt in which the mafic dykes were emplaced.Meanwhile,it is also indicated

  3. A review of the ascent and emplacement of granitoid bodies into the crust

    Directory of Open Access Journals (Sweden)

    Katarína Bónová

    2005-03-01

    Full Text Available This paper relates to basic information (i.e. mechanical aspects of ascent, indicators faciliting the discriminability of various ascent styles about the models of ascent and emplacement of granitoid bodies, since the purely mechanical aspect of intrusion of magmas is a fascinating subject and it has generated a considerable controversy over many years. Individual models are demonstrated by world-known occurrences and examples from Western Carpathian’s region. The conditions of magma migration are demonstrated as well.

  4. Cripple Creek and other alkaline-related gold deposits in the Southern Rocky Mountains, USA: Influence of regional tectonics

    Science.gov (United States)

    Kelley, K.D.; Ludington, S.

    2002-01-01

    Alkaline-related epithermal vein, breccia, disseminated, skarn, and porphyry gold deposits form a belt in the southern Rocky Mountains along the eastern edge of the North American Cordillera. Alkaline igneous rocks and associated hydrothermal deposits formed at two times. The first was during the Laramide orogeny (about 70-40 Ma), with deposits restricted spatially to the Colorado mineral belt (CMB). Other alkaline igneous rocks and associated gold deposits formed later, during the transition from a compressional to an extensional regime (about 35-27 Ma). These younger rocks and associated deposits are more widespread, following the Rocky Mountain front southward, from Cripple Creek in Colorado through New Mexico. All of these deposits are on the eastern margin of the Cordillera, with voluminous calc-alkaline rocks to the west. The largest deposits in the belt include Cripple Creek and those in the CMB. The most important factor in the formation of all of the gold deposits was the near-surface emplacement of relatively oxidized volatile-rich alkaline magmas. Strontium and lead isotope compositions suggest that the source of the magmas was subduction-modified subcontinental lithosphere. However, Cripple Creek alkaline rocks and older Laramide alkaline rocks in the CMB that were emplaced through hydrously altered LREE-enriched rocks of the Colorado (Yavapai) province have 208Pb/204Pb ratios that suggest these magmas assimilated and mixed with significant amounts of lower crust. The anomalously hot, thick, and light crust beneath Colorado may have been a catalyst for large-scale transfer of volatiles and crustal melting. Increased dissolved H2O (and CO2, F, Cl) of these magmas may have resulted in more productive gold deposits due to more efficient magmatic-hydrothermal systems. High volatile contents may also have promoted Te and V enrichment, explaining the presence of fluorite, roscoelite (vanadium-rich mica) and tellurides in the CMB deposits and Cripple Creek as

  5. Volcanic Flooding Experiments in Impact Basins and Heavily Cratered Terrain Using LOLA Data: Patterns of Resurfacing and Crater Loss

    Science.gov (United States)

    Whitten, Jennifer L.; Head, James W.; Neumann, Gregory A.; Zuber, Maria T.; Smith, David E.

    2012-01-01

    Terrestrial planetary bodies are characterized by extensive, largely volcanic deposits covering their surfaces. On Earth large igneous provinces (LIPs) abound, maria cover the nearside of the Moon, and volcanic plains cover large portions of Venus, Mars and Mercury.

  6. EVALUATION OF RISKS AND WASTE CHARACTERIZATION REQUIREMENTS FOR THE TRANSURANIC WASTE EMPLACED IN WIPP DURING 1999

    International Nuclear Information System (INIS)

    Channell, J.K.; Walker, B.A.

    2000-01-01

    Specifically this report: 1. Compares requirements of the WAP that are pertinent from a technical viewpoint with the WIPP pre-Permit waste characterization program, 2. Presents the results of a risk analysis of the currently emplaced wastes. Expected and bounding risks from routine operations and possible accidents are evaluated; and 3. Provides conclusions and recommendations

  7. Origin of the mafic microgranular enclaves (MMEs) and their host granitoids from the Tagong pluton in Songpan-Ganze terrane: An igneous response to the closure of the Paleo-Tethys ocean

    Science.gov (United States)

    Chen, Qiong; Sun, Min; Zhao, Guochun; Yang, Fengli; Long, Xiaoping; Li, Jianhua; Wang, Jun; Yu, Yang

    2017-10-01

    The Songpan-Ganze terrane is mainly composed of a Triassic sedimentary sequence and late Triassic-Jurassic igneous rocks. A large number of plutons were emplaced as a result of tectono-magmatic activity related to the late stages of Paleo-Tethys ocean closure and ensuing collision. Granitoids and their hosted mafic enclaves can provide important constraints on the crust-mantle interaction and continental crustal growth. Mesozoic magmatism of Songpan-Ganze remains enigmatic with regard to their magma generation and geodynamic evolution. The Tagong pluton (209 Ma), in the eastern part of the Songpan-Ganze terrane, consists mainly of monzogranite and granodiorite with abundant coeval mafic microgranular enclaves (MMEs) (ca. 208-209 Ma). The pluton comprises I-type granitoid that possesses intermediate to acidic compositions (SiO2 = 61.6-65.8 wt.%), high potassium (K2O = 3.2-4.1 wt.%), and high Mg# (51-54). They are also characterized by arc-type enrichment of LREEs and LILEs, depletion of HFSEs (e.g. Nb, Ta, Ti) and moderate Eu depletions (Eu/Eu* = 0.46-0.63). Their evolved zircon Hf and whole-rock Nd isotopic compositions indicate that their precursor magmas were likely generated by melting of old lower continental crust. Comparatively, the MMEs have lower SiO2 (53.4-58.2 wt.%), higher Mg# (54-67) and show covariation of major and trace elements, coupled with field and petrographic observations, such as the disequilibrium textures of plagioclase and amphibole, indicating that the MMEs and host granitoids were originated from different magma sources but underwent mafic-felsic magma mixing process. Geochemical and isotopic data further suggest that the precursor magma of the MMEs was formed in the continental arc setting, mainly derived from an ancient metasomatized lithospheric mantle wedge. The Triassic granitoids from the Songpan-Ganze terrane show remarkable temporal-spatial-petrogenetic affinities to the counterparts of subduction zones in the Yidun and Kunlun arc

  8. The Lagoa Real uranium province, Bahia state, Brazil: some petrographic aspects and fluid inclusion studies

    International Nuclear Information System (INIS)

    Fuzikawa, K.; Alves, J.V.; Cuney, M.; Kostolanyl, C.; Poti, B.

    1988-01-01

    The Lagoa Real Uranium Province in the central-southern Bahia State, consisting of six deposits and several prospects, has a reserve of near one hundred tons of U 3 O 8 . The main lithological unit in the area is the Lagoa Real Complex which is formed by granites and gneisses derived from them. The unit overthrusts the Espinhaco metasediments the west. The Complex is the host of albities which may contain uraninite. The mineralization is manly associated with pyroxene and garnet. Petrographic and field relations indicate the overthrusting as the latest event, having left implants in the orebodies and their hosts. Fluid inclusion studies indicated fluids of different characteristics in the Espinhaco and the Lagoa Real Complex although they were similar in composition (carbonic and aqueous). The types inclusions detected are in agreement with the geologic processes suggested for the area: emplacement of the Sao Timoteo granite at 1.72 Ga; albitization and uranium mineralization at ∼ 1.4 Ga; and metamorphism at ∼ 0.49 Ga. The study is an example of fluid inclusion behaviour in a metamorphic process with very limited amount of fluids. (author) [pt

  9. Evolution of KREEP - Further petrologic evidence. [igneous rocks from Apollo 15 site

    Science.gov (United States)

    Crawford, M. L.; Hollister, L. S.

    1977-01-01

    It is hypothesized that KREEP samples from the Apollo 15 site are igneous. To support the hypothesis, comparisons are made with other crystalline KREEP samples, especially 14310. It is noted that the low siderophile element content and lack of high pressure phenocrysts in the Apollo 15 KREEP may be indications of a slower rise of KREEP melt to the surface, when contrasted with sample 14310. Gravitational separation of Fe-Ni metal is proposed as a mechanism to account for the depletion of siderophile elements relative to the Si-rich component. It is further suggested that KREEP may be the parent of Apollo 12 and 15 basalts, as well as of granitic rocks, due to the liquid immiscibility occurring during the KREEP melt crystallization, and the subsequent independent evolution of the components.

  10. 1.8 billion years of fluid-crust interaction: A zircon oxygen isotope record for the lower crust, western Churchill Province, Canadian Shield

    Science.gov (United States)

    Petts, Duane C.; Moser, Desmond E.; Longstaffe, Frederick J.; Davis, William J.; Stern, Richard A.

    2014-04-01

    The western Churchill Province of the Canadian Shield experienced a prolonged and complex formation history (ca. 4.04 to 1.70 Ga), with evidence for multiple episodes of orogenesis and regional magmatic activity. Here we report on the oxygen isotopic compositions of garnet and zircon recovered from lower crustal xenoliths, which have U-Pb ages between ca. 3.5 and 1.7 Ga. Overall, zircon from four metabasite xenoliths from the Rankin Inlet sample suite have δ18O values ranging from + 5.5 to + 8.6‰. Zircon from three metatonalite/anorthosite xenoliths and five metabasite xenoliths from the Repulse Bay sample suite have δ18O values of + 5.6 to + 8.3‰. High δ18O values (> + 6.0‰) for the oldest igneous zircon cores (ca. 3.5 Ga and 3.0-2.6 Ga) indicate that their metatonalite/anorthosite protolith magmas were generated from, or had assimilated, supracrustal rocks that interacted previously with surface-derived fluids. Igneous zircon cores (ca. 2.9-2.6 Ga) from one metabasite xenolith have δ18O values of + 5.6 to + 6.4‰, which suggests a formation from a mantle-derived basaltic/gabbroic magma. Metamorphic zircon cores (ca. 2.0-1.9 Ga) from one metabasite xenolith commonly have δ18O values between + 6.0 and + 6.3‰, which is indicative of a basalt/gabbro protolith and localized reworking of the lower crust caused by regional-scale plate convergence. The wide range of δ18O values (+ 5.5 to + 8.3‰) for ca. 1.75-1.70 Ga metamorphic zircon rims (identified in all xenoliths) indicates regional transient heating and reworking of mantle- and supracrustal-derived crust, induced by magmatic underplating along the crust-mantle boundary.

  11. Emplacement of zero-valent metal for remediation of deep contaminant plumes

    International Nuclear Information System (INIS)

    Hubble, D.W.; Gillham, R.W.; Cherry, J.A.

    1997-01-01

    Some groundwater plumes containing chlorinated solvent contaminants are found to be so deep that current in situ remediation technologies cannot be economically applied. Also, source zones are often found to be too deep for removal or inaccessible due to surface features. Plumes emanating from these sources require containment or treatment. Containment technologies are available for shallow sites (< 15 m) and are being developed for greater depths. However, it is important to advance the science of reactive treatment - both for cut off of plumes and to contain and treat source zones. Zero-valent metal technology has been used for remediation of solvent plumes at sites in Canada, the UK and at several industrial and military sites in the USA. To date, all of the plumes treated with zero-valent metal (granular iron) have been at depths less than 15 m. This paper gives preliminary results of research into methods to emplace granular iron at depths in the range of 15 to 60 m. The study included review of available and emerging methods of installing barrier or reactive material and the selection, preliminary design and costing of several methods. The design of a treatment system for a 122 m wide PCE plume that, immediately down gradient from its source, extends from a depth of 24 to 37 m below the ground surface is used as a demonstration site. Both Permeable Reactive Wall and Funnel-and-Gate trademark systems were considered. The emplacement methods selected for preliminary design and costing were slurry wall, driven/vibrated beam, deep soil mixing and hydrofracturing injection. For each of these methods, the iron must be slurried for ease of pumping and placement using biodegradable polymer viscosifiers that leave the iron reactive

  12. Effects of irregular basement structure on the geometry and emplacement of frontal thrusts and duplexes in the Quebec Appalachians: Interpretations from well and seismic reflection data

    Science.gov (United States)

    Konstantinovskaya, E.; Malo, M.; Badina, F.

    2014-12-01

    Irregular basement geometry may affect thrust propagation in foreland fold-thrust belts creating a perturbation in structural continuity of hydrocarbon fields. Here we investigate how the irregular pattern of normal faults, along with the presence of uplifts and transverse faults in the Grenvillian basement has influenced the geometry and emplacement of frontal thrusts and duplexes in the parautochthonous domain of the southern Quebec Appalachians during the middle-late Ordovician Taconian orogeny. Integration of data from surface geology, wells, and 2D and 3D seismic reflection surveys into a regional-scale structural model is used to reconstruct the 3D geometry and emplacement history of one- and two-horse duplexes in the Joly-Saint-Flavien gas storage area. The normal hinterland to foreland sequence of thrusting in this area is complicated by the differential emplacement of tectonic slices along strike of the orogenic front, starting in the SW and developing subsequently to the NE within each structural level. The shortening related to duplex emplacement decreases laterally over the distance of 20 km from - 49% in the SW (Joly area) to - 31% in the NE (Saint-Flavien area). Duplex emplacement resulted from the differential forward propagation, deflexion and vertical-axis rotation of the roof thrust (Logan's Line), which, in turn, has been induced by the presence of frontal uplift and transverse faults in the basement. The structural-lithological analysis of tectonic slices and restoration of their initial location allows us to consider the lower slice of the Joly duplex as a structural trap comparable to the fractured reservoir in lower Ordovician dolomites of the Saint-Flavien duplex.

  13. Emplaced writing figuring as a manifestation of an ecocentric mindset in the narrative art of Petra Müller

    Directory of Open Access Journals (Sweden)

    Susan Meyer

    2014-06-01

    Full Text Available The human-earth connection is a sustained theme in Petra Müller’s oeuvre. The article focuses on this connection as reflected in her narrative art, specifically in accounts that have an autobiographical proclivity. The aim of this article is to outline the nature-centred disposition of Müller’s narrative art in a more definite sense. This is achieved by paying attention to the manner in which the author (the ‘I’ in accounts where the narrator can be identified as the author herself becomes part of the natural environment – whether on a sensory, an emotive, or an intellectual level – where she finds herself and the way she responds to it. At the core of the investigation are the ways in which this reactive engagement is manifested in Müller’s prose work by the implied author and the technique ofemplaced writing. Emplaced writing, a concept created by Linda Russo, was integrated by Susan Smith with Lawrence Buell’s concept of emplacement. This term refers to the technique allowing an active awareness of self and the place physically occupied by the author, as well as how that body fits into this place, to find expression. A broader perspective and greater appreciation of Müller’s work are drawn from the insight into how her close coexistence with the earth is reflected in her narrative art by means of the technique of emplaced writing which is explored in this article as it gives voice to a strong ecocentric disposition.

  14. The Wall-Rock Record of Incremental Emplacement in the Little Cottonwood-Alta Magmatic and Hydrothermal System, Wasatch Mountains, Utah, U.S.A.

    Science.gov (United States)

    Stearns, M.; Callis, S.; Beno, C.; Bowman, J. R.; Bartley, J. M.

    2017-12-01

    Contact aureoles record the cumulative effects on wall rocks of magma emplacement. Like the plutons they surround, contact aureoles have long been regarded to form geologically instantaneously. Protracted incremental emplacement of plutons must be reconciled with the wall-rock record of heat and mass transfer. Fundamental questions include how heat and material move from intrusions into their aureoles and how long that process takes. The Little Cottonwood stock is surrounded by a 2 km-wide contact aureole that contains prograde AFM mineral assemblages in the pelitic layers of the Proterozoic Big Cottonwood Formation. The Alta stock is surrounded by a well characterized 1 km-wide contact aureole containing both prograde AFM and CMS mineral assemblages in Ophir Shale and Mississippian dolostones, respectively. Understanding the petrogenesis of these aureoles requires the timing of magmatism and wall-rock metamorphism to be independently determined. Preliminary petrochronology (U/Th-Pb dates and trace element concentrations collected by LASS-ICP-MS) from the inner aureoles of both intrusions establishes a protracted history of monazite (re)crystallization from 35-25 Ma in the Little Cottonwood aureole and 35 Ma in the Alta aureole. Little Cottonwood aureole monazites are characterized by a positive age correlation with heavy rare earth elements (HREE) and a negative correlation with Eu/Eu*. Alta aureole monazites have a similar range of the HREE concentrations and Eu/Eu* variation. Zircon growth interpreted to record emplacement-level magmatic crystallization of the western Little Cottonwood stock ranges from 33-28 Ma near the contact. Multi-grain U-Pb zircon TIMS dates from the Alta stock range from 35-33 Ma and are interpreted to suggest the full range of emplacement-level magmatism in the Alta stock. Additionally, in situ U-Pb titanite dates from the Alta stock record intermittent high temperature hydrothermal activity in the stock margin from 35-24 Ma. These new

  15. The Jeffers Brook diorite-granodiorite pluton: style of emplacement and role of volatiles at various crustal levels in Avalonian appinites, Canadian Appalachians

    Science.gov (United States)

    Pe-Piper, Georgia; Piper, David J. W.

    2018-04-01

    Small appinite plutons ca. 610 Ma outcrop in the peri-Gondwanan Avalon terrane of northern Nova Scotia, with different structural levels exposed. Field mapping shows that the Jeffers Brook pluton is a laccolith emplaced along an upper crustal thrust zone, likely in a dilational jog in a regional dextral strike-slip system. The oldest rocks are probably mafic sills, which heated the area facilitating emplacement of intermediate magmas. Cross-cutting relationships show that both mafic and intermediate magmas were supplied throughout the history of pluton emplacement. The modal composition, mineral chemistry, and bulk chemistry of gabbro, diorite, tonalite, granodiorite, and granite have been studied in the main plutonic phases, dykes, and sills, and mafic microgranular enclaves. As with the type appinites in the Scottish Caledonides, the pluton shows evidence of high water content: the dominance of hornblende, locally within pegmatitic texture; vesicles and irregular felsic patches in enclaves; and late aplite dykes. Analyzed mafic microgranular enclaves are geochemically similar to larger diorite bodies in the pluton. Tonalite-granodiorite is distinct from the diorite in trace-element geochemistry and radiogenic isotopes. Elsewhere to the east, similar rocks of the same age form vertically sheeted complexes in major shear zones; hornblende chemistry shows that they were emplaced at a deeper upper crustal level. This implies that little of the observed geochemical variability in the Jeffers Brook pluton was developed within the pluton. The general requirements to form appinites are proposed to be small magma volumes of subduction-related magmas that reach the upper crust because of continual heating by mafic magmas moving through strike-slip fault pathways and trapping of aqueous fluids rather than venting through volcanic activity.

  16. Dike/Drift Interactions

    Energy Technology Data Exchange (ETDEWEB)

    E. Gaffiney

    2004-11-23

    This report presents and documents the model components and analyses that represent potential processes associated with propagation of a magma-filled crack (dike) migrating upward toward the surface, intersection of the dike with repository drifts, flow of magma in the drifts, and post-magma emplacement effects on repository performance. The processes that describe upward migration of a dike and magma flow down the drift are referred to as the dike intrusion submodel. The post-magma emplacement processes are referred to as the post-intrusion submodel. Collectively, these submodels are referred to as a conceptual model for dike/drift interaction. The model components and analyses of the dike/drift interaction conceptual model provide the technical basis for assessing the potential impacts of an igneous intrusion on repository performance, including those features, events, and processes (FEPs) related to dike/drift interaction (Section 6.1).

  17. Dike/Drift Interactions

    International Nuclear Information System (INIS)

    Gaffiney, E.

    2004-01-01

    This report presents and documents the model components and analyses that represent potential processes associated with propagation of a magma-filled crack (dike) migrating upward toward the surface, intersection of the dike with repository drifts, flow of magma in the drifts, and post-magma emplacement effects on repository performance. The processes that describe upward migration of a dike and magma flow down the drift are referred to as the dike intrusion submodel. The post-magma emplacement processes are referred to as the post-intrusion submodel. Collectively, these submodels are referred to as a conceptual model for dike/drift interaction. The model components and analyses of the dike/drift interaction conceptual model provide the technical basis for assessing the potential impacts of an igneous intrusion on repository performance, including those features, events, and processes (FEPs) related to dike/drift interaction (Section 6.1)

  18. Correlation between parent and daughter element concentrations as a means of valuing isochrons of igneous rocks

    International Nuclear Information System (INIS)

    Wetzel, K.

    1989-01-01

    The question whether a series of samples from an igneous rock can be attributed to an isochron for radiogeochronological dating or for determining the initial isotope ratio of the daughter element of the radioactive decay can be valued by investigating the correlation between the concentrations 1 c and 2 c of mother ( 1 c) and daughter element ( 2 c). The slope of the regression line in a lg 1 c to lg 2 c diagram is given by 1 D - 1/ 2 D - 1 or 1 D - 1/ 2 D - 1 · 2 D/ 1 D, where 1 D and 2 D are the solid-liquid distribution coefficients of parent and daughter element, if the concentration patterns are ruled by fractional crystallization or by partial melting, respectively. The agreement between experimentally found slopes and those calculated from distribution coefficients thus gives additional evidence whether or not the isochron reflects a magma solidification or magma generation age, respectively. The method is discussed for the Rb-Sr-, Sm-Nd-, La-Ce-, La-Ba- and K-Ca-geochronometers, using distribution coefficients calculated on the basis of a global model of the generation of the most abundant continental igneous rocks. The application on Rb-Sr-isochrons of a series of various granites of the Erzgebirge and the Saxonian Granulite Massif in the Southern Part of the GDR reveals new evidence of postmagmatic autosomatosis having altered the chemical composition of the Younger granites of the Western Ore Mountains (Erzgebirge). (author)

  19. Paleomagnetism in the Determination of the Emplacement Temperature of Cerro Colorado Tuff Cone, El Pinacate Volcanic Field, Sonora, Mexico.

    Science.gov (United States)

    Rodriguez Trejo, A.; Alva-Valdivia, L. M.; Vidal Solano, J. R.; Garcia Amador, B.; Gonzalez-Rangel, J. A.

    2014-12-01

    Cerro Colorado Maar is located at the World Heritage Site, biosphere reserve El Pinacate and Gran Desierto del Altar, at the NNW region of Sonora, Mexico (in El Pinacate Volcanic Field). It is a tuff cone, about 1 km diameter, result of several phreatomagmatic episodes during the late Quaternary. We report paleomagnetic and rock magnetic properties from fusiform volcanic bombs obtained from the borders of Cerro Colorado. This study is based in the thermoremanent magnetization TRM normally acquired by volcanic rocks, which can be used to estimate the emplacement temperature range. We performed the experiments on 20 lithic fragments (10 cm to 20 cm approximately), taking 6-8 paleomagnetic cores from each. Rock magnetic experiments (magnetic susceptibility vs. temperature (k-T), hysteresis curves and FORC analysis, shows that the main magnetic mineral carriers of magnetization are titanomagnetite and titanohematite in different levels of intergrowth. The k-T curves suggest in many cases, only one magnetic phase, but also in other cases a second magnetic phase. Thermal demagnetization was used to demagnetize the specimens in detailed short steps and make a well-defined emplacement temperature determination ranges. We found that temperature emplacement determination range for these two magnetic phases is between 350-450 °C, and 550-580 °C, respectively. These results are consistent with those expected in an eruption of Surtsey type, showing a distinct volcanic activity compared to the other craters from El Pinacate volcanic field.

  20. Tracking lava flow emplacement on the east rift zone of Kīlauea, Hawai‘i, with synthetic aperture radar coherence

    Science.gov (United States)

    Dietterich, Hannah R.; Poland, Michael P.; Schmidt, David A.; Cashman, Katharine V.; Sherrod, David R.; Espinosa, Arkin Tapia

    2012-05-01

    Lava flow mapping is both an essential component of volcano monitoring and a valuable tool for investigating lava flow behavior. Although maps are traditionally created through field surveys, remote sensing allows an extraordinary view of active lava flows while avoiding the difficulties of mapping on location. Synthetic aperture radar (SAR) imagery, in particular, can detect changes in a flow field by comparing two images collected at different times with SAR coherence. New lava flows radically alter the scattering properties of the surface, making the radar signal decorrelated in SAR coherence images. We describe a new technique, SAR Coherence Mapping (SCM), to map lava flows automatically from coherence images independent of look angle or satellite path. We use this approach to map lava flow emplacement during the Pu`u `Ō`ō-Kupaianaha eruption at Kīlauea, Hawai`i. The resulting flow maps correspond well with field mapping and better resolve the internal structure of surface flows, as well as the locations of active flow paths. However, the SCM technique is only moderately successful at mapping flows that enter vegetation, which is also often decorrelated between successive SAR images. Along with measurements of planform morphology, we are able to show that the length of time a flow stays decorrelated after initial emplacement is linearly related to the flow thickness. Finally, we use interferograms obtained after flow surfaces become correlated to show that persistent decorrelation is caused by post-emplacement flow subsidence.

  1. Tracking lava flow emplacement on the east rift zone of Kilauea, Hawai’i with synthetic aperture radar (SAR) coherence

    Science.gov (United States)

    Dietterich, Hannah R.; Poland, Michael P.; Schmidt, David; Cashman, Katharine V.; Sherrod, David R.; Espinosa, Arkin Tapia

    2012-01-01

    Lava flow mapping is both an essential component of volcano monitoring and a valuable tool for investigating lava flow behavior. Although maps are traditionally created through field surveys, remote sensing allows an extraordinary view of active lava flows while avoiding the difficulties of mapping on location. Synthetic aperture radar (SAR) imagery, in particular, can detect changes in a flow field by comparing two images collected at different times with SAR coherence. New lava flows radically alter the scattering properties of the surface, making the radar signal decorrelated in SAR coherence images. We describe a new technique, SAR Coherence Mapping (SCM), to map lava flows automatically from coherence images independent of look angle or satellite path. We use this approach to map lava flow emplacement during the Pu‘u ‘Ō‘ō-Kupaianaha eruption at Kīlauea, Hawai‘i. The resulting flow maps correspond well with field mapping and better resolve the internal structure of surface flows, as well as the locations of active flow paths. However, the SCM technique is only moderately successful at mapping flows that enter vegetation, which is also often decorrelated between successive SAR images. Along with measurements of planform morphology, we are able to show that the length of time a flow stays decorrelated after initial emplacement is linearly related to the flow thickness. Finally, we use interferograms obtained after flow surfaces become correlated to show that persistent decorrelation is caused by post-emplacement flow subsidence.

  2. Solar PV Industry in Jiangsu Province [China

    International Nuclear Information System (INIS)

    2010-03-01

    Jiangsu Province is a leading province in China both in terms of Solar PV application as well as its implementation. The Netherlands Business Support Office in Nanjing reports on the photovoltaic solar cell industry in Jiangsu Province with details on opportunities for foreign investors; applications of solar energy in the province; Chinese government; relevant organizations; and key Chinese players in this sector.

  3. Lead-isotope inhomogeneity in Precambrian igneous K-feldspars

    International Nuclear Information System (INIS)

    Ludwig, K.R.; Silver, L.T.

    1977-01-01

    Stepwise PB-removal experiments, using both vacuum volatilization and HF-leaching techniques, on acid-washed K-feldspar concentrates from Precambrian igneous rocks show that all contain some unsupported radiogenic Pb. Two types of radiogenic Pb were recognised. One has a 'normal' isotopic composition, with relative abundances of 206 Pb, 207 Pb and 208 Pb consistent with the age and U-Th contents of the rocks. The other type of unsupported radiogenic lead in the feldspars is apparently pure 206 Pb, derived from long-term migration and accumulation of radioactive daughter(s) of 238 U. This 'pure' 206 Pb lead occupies different sites from the 'normal' radiogenic lead, and tends to show a release maximum during vacuum volatilization at about 1150 0 C. The usefulness of stepwise vacuum volatilization may be limited by the tendency of a small amount of radiogenic lead to concentrate in the least volatile fraction. Stepwise partial HF attacks appear to give at least as good separation of radiogenic from original feldspar lead, and are recommended as a routine procedure for isotopic analyses of Precambrian feldspars. The fact that most of the five K-feldspars examined contained unsupported radiogenic lead implies that caution must be used in applying total-sample lead analyses of Precambrian feldspars to problems of lead-isotope evolution in crustal rocks. (author)

  4. Ages, geochemistry and tectonic implications of the Cambrian igneous rocks in the northern Great Xing'an Range, NE China

    Science.gov (United States)

    Feng, Zhiqiang; Liu, Yongjiang; Li, Yanrong; Li, Weimin; Wen, Quanbo; Liu, Binqiang; Zhou, Jianping; Zhao, Yingli

    2017-08-01

    The Xinlin-Xiguitu suture zone, located in the Great Xing'an Range, NE China, in the eastern segment of the Central Asian Orogenic Belt (CAOB), represents the boundary between the Erguna and Xing'an micro-continental blocks. The exact location of the Xinlin-Xiguitu suture zone has been debated, especially, the location of the northern extension of the suture zone. In this study, based on a detailed field, geochemical, geochronological and Sr-Nd-Hf isotope study, we focus our work on the Cambrian igneous rocks in the Erguna-Xing'an block. The Xinglong granitoids, mainly include ∼520 Ma diorite, ∼470 Ma monzogranite and ∼480 Ma pyroxene diorite. The granitoids show medium to high-K calc-alkaline series characteristics with post-collision granite affinity. The circa 500 Ma granitoids have low εHf (t) values (-16.6 to +2.2) and ancient two-stage model (TDM2) ages between 1317 Ma and 2528 Ma. These results indicate the primary magmas of the Xinglong granitoids were probably derived from the partial melting of a dominantly Paleo-Mesoproterozoic ;old; crustal source with possible different degrees of addition of juvenile materials, and formed in a post-collision tectonic setting after the amalgamation of the Erguna and Xing'an blocks. Compared with the Xinglong granitoids, the Duobaoshan igneous rocks are consisted of the approximately coeval rhyolitic tuffs (491 ± 5 Ma) and ultramafic intrusions (497 ± 5 Ma) within the Duobaoshan Formation. They are generally enriched in large ion lithophile elements (LILEs) and depleted in high field strength elements (HFSEs; e.g., Nb, Ta, and Ti), consistent with the geochemistry of igneous rocks from island arcs or active continental margins. The ultramafic rocks have high positive εHf (t) values (+1.3 to +15) and εNd (t) (+1.86 to +2.28), and relatively young two-stage model (TDM2) ages and low initial 87Sr/86Sr ratios (0.70628-0.70853), indicating the partial melting of a depleted mantle source from a subducted slab in

  5. Engineering studies: high-level radioactive waste repositories task 3 - review of underground handling and emplacement. 1. Executive summary

    Energy Technology Data Exchange (ETDEWEB)

    1981-02-01

    The report reviews proposals for transport, handling and emplacement of high-level radioactive waste in an underground repository with particular reference to: waste block size and configuration; self-shielded or partially-shielded block; stages of disposal; transport by road/rail to repository site; handling techniques within repository; emplacement in vertical holes or horizontal tunnels; repository access by adit, incline or shaft; conventional and radiological safety; costs; and major areas of uncertainty requiring research or development. In carrying out this programme due attention was given to work already carried out both in the U.K. and overseas and where appropriate comparisons with this work have been made to substantiate and explain the observations made in this report. The examination and use of this previous work however has been confined to those proposals which were considered capable of meeting the basic design criterion for a U.K. based repository, that the maximum temperature achieved by the host rock should not exceed 100/sup 0/C.

  6. Site characterization plan conceptual design report for a high-level nuclear waste repository in salt, vertical emplacement mode: Volume 1

    International Nuclear Information System (INIS)

    1987-12-01

    This Conceptual Design Report describes the conceptual design of a high-level nuclear waste repository in salt at a proposed site in Deaf Smith County, Texas. Waste receipt, processing, packing, and other surface facility operations are described. Operations in the shafts underground are described, including waste hoisting, transfer, and vertical emplacement. This report specifically addresses the vertical emplacement mode, the reference design for the repository. Waste retrieval capability is described. The report includes a description of the layout of the surface, shafts, and underground. Major equipment items are identified. The report includes plans for decommissioning and sealing of the facility. The report discusses how the repository will satisfy performance objectives. Chapters are included on basis for design, design analyses, and data requirements for completion of future design efforts. 105 figs., 52 tabs

  7. Site characterization plan conceptual design report for a high-level nuclear waste repository in salt, vertical emplacement mode: Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    1987-12-01

    This Conceptual Design Report describes the conceptual design of a high-level nuclear waste repository in salt at a proposed site in Deaf Smith County, Texas. Waste receipt, processing, packing, and other surface facility operations are described. Operations in the shafts underground are described, including waste hoisting, transfer, and vertical emplacement. This report specifically addresses the vertical emplacement mode, the reference design for the repository. Waste retrieval capability is described. The report includes a description of the layout of the surface, shafts, and underground. Major equipment items are identified. The report includes plans for decommissioning and sealing of the facility. The report discusses how the repository will satisfy performance objectives. Chapters are included on basis for design, design analyses, and data requirements for completion of future design efforts. 105 figs., 52 tabs.

  8. Site characterization plan conceptual design report for a high-level nuclear waste repository in salt, horizontal emplacment mode: Volume 1

    International Nuclear Information System (INIS)

    1987-12-01

    This Conceptual Design Report describes the conceptual design of a high-level nuclear waste repository in salt at a proposed site in Deaf Smith County, Texas. Waste receipt, processing, packaging, and other surface facility operations are described. Operations in the shafts and underground are described, including waste hoisting, transfer, and horizontal emplacement. This report specifically addresses the horizontal emplacement mode, the passive alternate design for the repository. Waste retrieval capability is described. The report includes a description of the layout of the surface, shafts, and underground. Major equipment items are identified. The report includes plans for decommissioning and sealing of the facility. The report discusses how the repository will satisfy performance objectives. Chapters are included on basis for design, design analyses, and data requirements for completion of future design efforts. 105 figs., 52 tabs

  9. Effects of the deviation characteristics of nuclear waste emplacement boreholes on borehole liner stresses; Yucca Mountain Project

    Energy Technology Data Exchange (ETDEWEB)

    Glowka, D.A.

    1990-09-01

    This report investigates the effects of borehole deviation on the useability of lined boreholes for the disposal of high-level nuclear waste at the proposed Yucca Mountain Repository in Nevada. Items that lead to constraints on borehole deviation include excessive stresses that could cause liner failure and possible binding of a waste container inside the liner during waste emplacement and retrieval operations. Liner stress models are developed for two general borehole configurations, one for boreholes drilled with a steerable bit and one for boreholes drilled with a non-steerable bit. Procedures are developed for calculating liner stresses that arise both during insertion of the liner into a borehole and during the thermal expansion process that follows waste emplacement. The effects of borehole curvature on the ability of the waste container to pass freely inside the liner without binding are also examined. Based on the results, specifications on borehole deviation allowances are developed for specific vertical and horizontal borehole configurations of current interest. 11 refs., 22 figs., 4 tabs.

  10. Ca. 890 Ma magmatism in the northwest Yangtze block, South China: SIMS U-Pb dating, in-situ Hf-O isotopes, and tectonic implications

    Science.gov (United States)

    Zhou, Jiu-Long; Li, Xian-Hua; Tang, Guo-Qiang; Gao, Bing-Yu; Bao, Zhi-An; Ling, Xiao-Xiao; Wu, Li-Guang; Lu, Kai; Zhu, Yu-Sheng; Liao, Xin

    2018-01-01

    Early Neoproterozoic tectonics of the Yangtze block remains poorly understood because very limited igneous records are available from the time interval of ∼1000-870 Ma. In this paper, our new SIMS U-Pb dating results demonstrate that the Liushudian mafic intrusion and Pinghe alkaline complex in the northwest Yangtze block were emplaced at 888 ± 6 Ma and 891 ± 7 Ma, respectively, representing the products of a ∼890 Ma igneous event. Gabbros from the Liushudian intrusion have rather depleted zircon ɛHf(t) (mean = 10.4) and normal mantle-like zircon δ18O (mean = 5.97‰). Their parental magma was thus probably derived from asthenospheric mantle. Geochemically, these mafic rocks have an affinity to continental flood tholeiitic basalts rather than ocean island basalts, as previously thought. In contrast, an ijolite sample from the Pinghe complex has less depleted zircon ɛHf(t) (mean = 5.7) and anomalously high zircon and apatite δ18O (mean = 13.76‰ and 13.80‰, respectively). Such a characteristic δ18O signal, among the highest yet known for igneous zircons, could be either inherited from a magma source in metasomatized lithospheric mantle or acquired by assimilation of high-δ18O supracrustal materials (e.g., limestone, chert) during magma evolution. An intra-plate extensional environment is suggested for the ∼890 Ma igneous event in the northwest Yangtze block, although it is as yet unclear whether this igneous event is related to a mantle plume or not. It could be concluded that magmatism on the western periphery of the Yangtze block was not shut down between ∼1000 and ∼870 Ma, and the ∼890 Ma intra-plate igneous event may mark either the onset of Neoproterozoic continental rifting or the ending of Late Mesoproterozoic to Early Neoproterozoic lithospheric extension.

  11. Root zone of a continental rift

    DEFF Research Database (Denmark)

    Kirsch, Moritz; Svenningsen, Olaf

    2016-01-01

    melt are considered to account for the compositional range exhibited by the KIC igneous rocks. U/Pb SIMS geochronological data from zircon rims yield an emplacement age of 578 ± 9 Ma. The KIC is thus younger and more depleted than coeval mafic rocks found in the Seve Nappe, and is interpreted...... to represent a high-level magma plumbing system in a late-stage continental rift. The composition and volume of rift-related igneous rocks in the Seve Nappes are inconsistent with a mantle plume origin, but are thought to record progressive lithospheric thinning and increasing involvement of an asthenospheric......Mafic magmatic rocks formed between ca. 615 and 560 Ma along the Neoproterozoic margins of Baltica and Laurentia are classically attributed to continental rifting heralding the opening of the Iapetus Ocean. We report new data for the Kebnekaise Intrusive Complex (KIC) exposed in the Seve Nappes...

  12. Lower Crstal Reflectity bands and Magma Emplacement in Norweigian sea, NE Atlantic

    Science.gov (United States)

    Rai, A.; Breivik, A. J.; Mjelde, R.

    2013-12-01

    In this study we present the OBS data collected along seismic profiles in the norweigian sea. The traveltime modelling of the OBS data provides first-hand information about seismic structure of the subsurface. However, waveform modelling is used to further constrain the fine scale structure, velocity constrast and velocity gradients. By forward modelling and inversion of the seismic waveforms, we show that the multiple bands of reflectivity could be due to multiple episodes of magma emplacements that might have frozen in the form of sills. These mafic intrusions probably intruded into the ductile lower crust during the main rifting phase of Europe and Greenland.

  13. Lack of inhibiting effect of oil emplacement on quartz cementation: Evidence from Cambrian reservoir sandstones, Paleozoic Baltic Basin

    DEFF Research Database (Denmark)

    Molenaar, Nicolaas; Cyziene, Jolanta; Sliaupa, Saulius

    2008-01-01

    Currently, the question of whether or not the presence of oil in sandstone inhibits quartz cementation and preserves porosity is still debated. Data from a number of Cambrian sandstone oil fields and dry fields have been studied to determine the effects of oil emplacement on quartz cementation. T...

  14. Geochronology, geochemistry and tectonic evolution of the Western and Central cordilleras of Colombia

    Science.gov (United States)

    Villagómez, Diego; Spikings, Richard; Magna, Tomas; Kammer, Andreas; Winkler, Wilfried; Beltrán, Alejandro

    2011-08-01

    Autochthonous rocks of the pre-Cretaceous continental margin of NW South America (the Tahami Terrane) are juxtaposed against a series of para-autochthonous rock units that assembled during the Early Cretaceous. Allochthonous, oceanic crust of the Caribbean Large Igneous Province collided with and accreted onto the margin during the Late Cretaceous. We present the first regional-scale dataset of zircon U-Pb LA-ICP-MS ages for intrusive and metamorphic rocks of the autochthonous Tahami Terrane, Early Cretaceous igneous para-autochthonous rocks and accreted oceanic crust. The U-Pb zircon data are complemented by multiphase 40Ar/ 39Ar crystallization and cooling ages. The geochronological data are combined with whole rock major oxide, trace element and REE data acquired from the same units to constrain the tectonic origin of the rock units and terranes exposed in the Western Cordillera, Cauca-Patía Valley and the Central Cordillera of Colombia. The Tahami Terrane includes lower Paleozoic orthogneisses (~ 440 Ma) that may have erupted during the active margin stage of the Rheic Ocean. Basement gneisses were intruded by Permian, continental arc granites during the final assembly of Pangea. Triassic sedimentary rocks were subsequently deposited in rift basins and partially melted during high-T metamorphism associated with rifting of western Pangea during 240-220 Ma. Continental arc magmatism during 180-145 Ma is preserved along the whole length of the Central Cordillera and was followed by an Early Cretaceous out-board step of the arc axis and the inception of the Quebradagrande Arc that fringed the continental margin. Back-stepping of the arc axis may have been caused by the collision of buoyant seamounts, which were coeval with plateau rocks exposed in the Nicoya Peninsular of Costa Rica. Rapid westward drift of South America closed the Quebradagrande basin in the late Aptian and caused medium-high P-T metamorphic rocks of the Arquía Complex to exhume and obduct onto

  15. 3D inversion and modeling of magnetic and gravimetric data characterizing the geophysical anomaly source in Pratinha I in the southeast of Brazil

    Science.gov (United States)

    Louro, Vinicius Hector Abud; Mantovani, Marta Silvia Maria

    2012-05-01

    The Alto do Paranaíba Igneous Province (APIP) is known for its great mineral exploratory interest in phosphates, niobium, titanium, and diamonds, among others. In the years of 2005 and 2006, the Economic Development Company of Minas Gerais (CODEMIG — http://www.comig.com.br/) performed an airborne magnetic survey over the portion of this igneous province which belongs to Minas Gerais state, denominated Area 7. This survey revealed at the coordinates (19°45'S, 46°10'W) a tripolar anomaly here referred as Pratinha I. This anomaly does not present evidences of outcropping or topographic remodeling. So, boreholes or studies over its sources make the geophysical methods the best and less expensive solution for studying the body in its subsurface. Besides, two gravimetric ground surveys were performed in 2009 and 2010, confirming the existence of a density contrast over the region of the magnetic anomaly. Therefore, through the magnetometry and gravimetry processing, 3D modeling and inversions, it was possible to estimate the geometry, density and magnetic susceptibility, which when analyzed with the regional geology, enabled the proposition of an igneous intrusion of probable alkaline or kamafugitic composition to justify the gravimetric and magnetic response in the region.

  16. Landsat investigations of the northern Paradox basin, Utah and Colorado: implications for radioactive waste emplacement

    Science.gov (United States)

    Friedman, Jules D.; Simpson, Shirley L.

    1978-01-01

    The first stages of a remote-sensing project on the Paradox basin, part of the USGS (U.S. Geological Survey) radioactive waste-emplacement program, consisted of a review and selection of the best available satellite scanner images to use in geomorphologic and tectonic investigations of the region. High-quality Landsat images in several spectral bands (E-2260-17124 and E-5165-17030), taken under low sun angle October 9 and 10, 1975, were processed via computer for planimetric rectification, histogram analysis, linear transformation of radiance values, and edge enhancement. A lineament map of the northern Paradox basin was subsequently compiled at 1:400,000 using the enhanced Landsat base. Numerous previously unmapped northeast-trending lineaments between the Green River and Yellowcat dome; confirmatory detail on the structural control of major segments of the Colorado, Gunnison, and Dolores Rivers; and new evidence for late Phanerozoic reactivation of Precambrian basement structures are among the new contributions to the tectonics of the region. Lineament trends appear to be compatible with the postulated Colorado lineament zone, with geophysical potential-field anomalies, and with a northeast-trending basement fault pattern. Combined Landsat, geologic, and geophysical field evidence for this interpretation includes the sinuousity of the composite Salt Valley anticline, the transection of the Moab-Spanish Valley anticline on its southeastern end by northeast-striking faults, and possible transection (?) of the Moab diapir. Similarly, northeast-trending lineaments in Cottonwood Canyon and elsewhere are interpreted as manifestations of structures associated with northeasterly trends in the magnetic and gravity fields of the La Sal Mountains region. Other long northwesterly lineaments near the western termination of the Ryan Creek fault zone. may be associated with the fault zone separating the Uncompahgre horst uplift from the Paradox basin. Implications of the

  17. A new chronology for the late Triassic to early Jurassic. Geologica Ultraiectina (323)

    NARCIS (Netherlands)

    Deenen, M.H.L.

    2010-01-01

    Throughout geological history of life, a small number of mass extinctions have forever changed the path of evolution. The two main mechanisms that account for these dramatic events are asteroid impacts and massive volcanic eruptions of Large Igneous Provinces (LIP’s). The interplay between

  18. U–Pb geochronology of the Eocene Kærven intrusive complex, East Greenland

    DEFF Research Database (Denmark)

    Þórarinsson, Sigurjón Böðvar; Holm, Paul Martin; Tappe, Sebatstian

    2016-01-01

    Several major tholeiitic (e.g. the Skaergaard intrusion) and alkaline (e.g. the Kangerlussuaq Syenite) intrusive complexes of the North Atlantic Large Igneous Province are exposed along the Kangerlussuaq Fjord in East Greenland. The Kærven Complex forms a satellite intrusion to the Kangerlussuaq ...

  19. Correlation of the Deccan and Rajahmundry Trap lavas: Are these the longest and largest lava flows on Earth?

    Science.gov (United States)

    Self, S.; Jay, A. E.; Widdowson, M.; Keszthelyi, L. P.

    2008-05-01

    We propose that the Rajahmundry Trap lavas, found near the east coast of peninsular India , are remnants of the longest lava flows yet recognized on Earth (˜ 1000 km long). These outlying Deccan-like lavas are shown to belong to the main Deccan Traps. Several previous studies have already suggested this correlation, but have not demonstrated it categorically. The exposed Rajahmundry lavas are interpreted to be the distal parts of two very-large-volume pāhoehoe flow fields, one each from the Ambenali and Mahabaleshwar Formations of the Wai Sub-group in the Deccan Basalt Group. Eruptive conditions required to emplace such long flows are met by plausible values for cooling and eruption rates, and this is shown by applying a model for the formation of inflated pāhoehoe sheet flow lobes. The model predicts flow lobe thicknesses similar to those observed in the Rajahmundry lavas. For the last 400 km of flow, the lava flows were confined to the pre-existing Krishna valley drainage system that existed in the basement beyond the edge of the gradually expanding Deccan lava field, allowing the flows to extend across the subcontinent to the eastern margin where they were emplaced into a littoral and/or shallow marine environment. These lavas and other individual flow fields in the Wai Sub-group may exceed eruptive volumes of 5000 km 3, which would place them amongst the largest magnitude effusive eruptive units yet known. We suggest that the length of flood basalt lava flows on Earth is restricted mainly by the size of land masses and topography. In the case of the Rajahmundry lavas, the flows reached estuaries and the sea, where their advance was perhaps effectively terminated by cooling and/or disruption. However, it is only during large igneous province basaltic volcanism that such huge volumes of lava are erupted in single events, and when the magma supply rate is sufficiently high and maintained to allow the formation of very long lava flows. The Rajahmundry lava

  20. Tumuli and associated features from the western Deccan Volcanic Province, India

    Science.gov (United States)

    Duraiswami, Raymond; Bondre, Ninad; Dole, Gauri; Phadnis, Vinit; Kale, Vivek

    2001-08-01

    Whale-back-shaped uplifts called "tumuli" are common in the pahoehoe flows of the western Deccan Volcanic Province (DVP). Although they usually occur in hummocky flows, they are also associated with thicker sheet lobes. They have been subjected to a detailed morphometric and petrographic study for the first time. The tumuli are characterised by positive relief and "lava-inflation clefts" occupied by squeeze-ups. They display elongate as well as equant forms; some are constituted of a single flow lobe, whereas others display multiple flow lobes. Some tumuli appear to have developed along anastomosing tube systems. The detailed study of one of the tumuli reveals considerable petrographic and textural variations among the constituent flow units. Some of these, such as the enrichment of phenocrysts in squeeze-ups and breakouts, could be related to the emplacement dynamics of the tumulus. All the observed tumuli display much evidence of inflation or endogenous growth. Field observations and measurements reveal that the tumuli and associated pahoehoe features display a close similarity with their Hawaiian counterparts. This is a very significant observation since it points out to a similarity in nature and style of eruptions in Hawaii and at least in the western part of the DVP. This has an important bearing on determining the short, medium and long-term effusion rates in the Deccan; however, any concrete inference will have to await systematic volcanological studies of the lava features in the DVP.

  1. Radioactive waste isolation in salt: Peer review of the Fluor Technology, Inc., report and position paper concerning waste emplacement mode and its effect on repository conceptual design

    International Nuclear Information System (INIS)

    Hambley, D.F.; Russell, J.E.; Whitfield, R.G.

    1987-02-01

    Recommendations for revising the Fluor Technology, Inc., draft position paper entitled Evaluation of Waste Emplacement Mode and the final report entitled Waste Package/Repository Impact Study include: reevaluate the relative rankings for the various emplacement modes; delete the following want objectives: maximize ability to locate the package horizon because sufficient flexibility exists to locate rooms in the relatively clean San Andres Unit 4 Salt and maximize far-field geologic integrity during retrieval because by definition the far field will be unaffected by thermal and stress perturbations caused by remining; give greater emphasis to want objectives regarding cost and use of present technology; delete the following statements from pages 1-1 and 1-2 of the draft position paper: ''No thought or study was given to the impacts of this configuration [vertical emplacement] on repository construction or short and long-term performance of the site'' and ''Subsequent salt repository designs adopted the vertical emplacement configuration as the accepted method without further evaluation.''; delete App. E and lines 8-17 of page 1-4 of the draft position paper because they are inappropriate; adopt a formal decision-analysis procedure for the 17 identified emplacement modes; revise App. F of the impact study to more accurately reflect current technology; consider designing the underground layout to take advantage of stress-relief techniques; consider eliminating reference to fuel assemblies <10 yr ''out-of-reactor''; model the temperature distribution, assuming that the repository is constructed in an infinitely large salt body; state that the results of creep analyses must be considered tentative until they can be validated by in situ measurements; and reevaluate the peak radial stresses on the waste package so that the calculated stress conditions more closely approximate expected in situ conditions

  2. Extra-terrestrial igneous granites and related rocks: A review of their occurrence and petrogenesis

    Science.gov (United States)

    Bonin, Bernard

    2012-11-01

    The telluric planets and the asteroid belt display the same internal structure with a metallic inner core and a silicate outer shell. Experimental data and petrological evidence in silicate systems show that granite can be produced by extreme igneous differentiation through various types of igneous processes. On Moon, 4.4-3.9 Ga granite clasts display dry mineral assemblages. They correspond to at least 8 discrete intrusive events. Large K/Ca enrichment and low REE abundances in granite relative to KREEP are consistent with silicate liquid immiscibility, a process observed in melt inclusions within olivine of lunar basalts and in lunar meteorites. Steep-sided domes identified by remote sensing can represent intrusive or extrusive felsic formations. On Mars, black-and-white rhythmic layers observed on the Tharsis rise along the flanks of the peripheral scarps of the Tharsis Montes giant volcanoes suggest the possible eruption of felsic pyroclastites. Though no true granites were found so far in the Martian SNC meteorites, felsic glasses and mesostases were identified and a component close to terrestrial continental (granitic) crust is inferred from trace element and isotope systematics. Venus has suffered extensive volcanic resurfacing, whereas folded and faulted areas resemble terrestrial continents. Near large shield volcanoes, with dominant basaltic compositions, steep-sided domes have been interpreted as non-degassed silicic extrusions. The hypothesis of a granitic component is "tantalising". Extra-terrestrial granite is frequently found as clasts and mesostases in asteroidal meteorites. Porphyritic textures, with alkali feldspar crystals up to several centimetres in size, were observed in silicate enclaves within iron meteorites. In the chondrite clan, polymict breccias can contain granitic clasts, whose provenance is debated. One clast from the Adzhi-Bogdo meteorite yields a 4.53 ± 0.03 Ga Pb-Pb age, making it the oldest known granite in the solar system. The

  3. Retrieval system for emplaced spent unreprocessed fuel (SURF) in salt bed depository: accident event analysis and mechanical failure probabilities. Final report

    International Nuclear Information System (INIS)

    Bhaskaran, G.; McCleery, J.E.

    1979-10-01

    This report provides support in developing an accident prediction event tree diagram, with an analysis of the baseline design concept for the retrieval of emplaced spent unreprocessed fuel (SURF) contained in a degraded Canister. The report contains an evaluation check list, accident logic diagrams, accident event tables, fault trees/event trees and discussions of failure probabilities for the following subsystems as potential contributors to a failure: (a) Canister extraction, including the core and ram units; (b) Canister transfer at the hoist area; and (c) Canister hoisting. This report is the second volume of a series. It continues and expands upon the report Retrieval System for Emplaced Spent Unreprocessed Fuel (SURF) in Salt Bed Depository: Baseline Concept Criteria Specifications and Mechanical Failure Probabilities. This report draws upon the baseline conceptual specifications contained in the first report

  4. Granite ascent and emplacement during contractional deformation in convergent orogens

    Science.gov (United States)

    Brown, Michael; Solar, Gary S.

    1998-09-01

    Based on a case study in the Central Maine Belt of west-central Maine, U.S.A., it is proposed that crustal-scale shear zone systems provide an effective focussing mechanism for transfer of granite melt through the crust in convergent orogens. During contractional deformation, flow of melt in crustal materials at depths below the brittle-plastic transition is coupled with plastic deformation of these materials. The flow is driven by pressure gradients generated by buoyancy forces and tectonic stresses. Within the oblique-reverse Central Maine Belt shear zone system, stromatic migmatite and concordant to weakly discordant irregular granite sheets occur in zones of higher strain, which suggests percolative flow of melt to form the migmatite leucosomes and viscous flow of melt channelized in sheet-like bodies, possibly along fractures. Cyclic fluctuations of melt pressure may cause instantaneous changes in the effective permeability of the flow network if self-propagating melt-filled tensile and/or dilatant shear fractures are produced due to melt-enhanced embrittlement. Inhomogeneous migmatite and schlieric granite occur in zones of lower strain, which suggests migration of partially-molten material through these zones en masse by granular flow, and channelized flow of melt carrying entrained residue. Founded on the Central Maine Belt case study, we develop a model of melt extraction and ascent using the driving forces, stress conditions and crustal rheologies in convergent, especially transpressive orogens. Ascent of melt becomes inhibited with decreasing depth as the solidus is approached. For intermediate a(H 2O) muscovite-dehydration melting, the water-saturated solidus occurs between 400 and 200 MPa, near the brittle-plastic transition during high- T-low- P metamorphism, where the balance of forces favors (sub-) horizontal fracture propagation. Emplacement of melt may be accommodated by ductile flow and/or stoping of wall rock, and inflation may be accommodated

  5. Ardnamurchan 3D cone-sheet architecture explained by a single elongate magma chamber.

    Science.gov (United States)

    Burchardt, Steffi; Troll, Valentin R; Mathieu, Lucie; Emeleus, Henry C; Donaldson, Colin H

    2013-10-08

    The Palaeogene Ardnamurchan central igneous complex, NW Scotland, was a defining place for the development of the classic concepts of cone-sheet and ring-dyke emplacement and has thus fundamentally influenced our thinking on subvolcanic structures. We have used the available structural information on Ardnamurchan to project the underlying three-dimensional (3D) cone-sheet structure. Here we show that a single elongate magma chamber likely acted as the source of the cone-sheet swarm(s) instead of the traditionally accepted model of three successive centres. This proposal is supported by the ridge-like morphology of the Ardnamurchan volcano and is consistent with the depth and elongation of the gravity anomaly underlying the peninsula. Our model challenges the traditional model of cone-sheet emplacement at Ardnamurchan that involves successive but independent centres in favour of a more dynamical one that involves a single, but elongate and progressively evolving magma chamber system.

  6. Age of Tertiary volcanic rocks on the West Greenland continental margin

    DEFF Research Database (Denmark)

    Larsen, Lotte M.; Pedersen, Asger Ken; Tegner, Christian

    2016-01-01

    across the entire North Atlantic Igneous Province. A quiescent 58–56 Ma period correlates with similar periods in East Greenland and the Faroes, and the Naqerloq Formation is coeval with the Eocene basalts in East Greenland. The Paleocene and Eocene tholeiitic basalts are distinguishable chemically...

  7. Age of the youngest Palaeogene flood basalts in East Greenland

    DEFF Research Database (Denmark)

    Heilmann-Clausen, C.; Piasecki, Stefan; Abrahamsen, Niels

    2008-01-01

    results, this constrains the termination of the East Greenland Paleogene Igneous Province to the Early-Middle Eocene transition (nannoplankton chronozones NP13-NP14/earliest NP15). This is 6-8 Ma younger than according to previous biostratigraphic age assignments. The new data show that flood basalt...

  8. ERG [Engineering Review Group] and GRG [Geologic Review Group] review of the horizontal versus vertical modes of waste emplacement at the Deaf Smith County site, Texas

    International Nuclear Information System (INIS)

    Chytrowski, B.R.

    1988-01-01

    The Engineering Review Group (ERG) and Geologic Review Group (GRG) were established by the Office of Nuclear Waste Isolation (ONWI) to help evaluate specific issues in the US Department of Energy's nuclear waste repository program. The December 1985 meeting and the February 1986 meeting dealt with the evaluation of the Fluor Technology, Inc., architect-engineer recommendation of the horizontal mode of waste package emplacement for the Site Characterization Plan Conceptual Design Report (SCP-CDR). The ONWI recommendation regarding horizontal and vertical modes of waste package emplacement and associated studies was reviewed. This report documents the ERG and GRG's comments and recommendations on this subject and ONWI responses to the specific points raised by these groups. The ERG and GRG joint review groups concurred with ONWI recommendations that additional studies are required in order to reach a decision on the method of emplacement to be used. In the opinion of these groups, both methods can be implemented; however, should the decision be reached today the vertical mode would be preferred

  9. Political rotations and cross-province acquisitions in China

    DEFF Research Database (Denmark)

    Muratova, Yulia; Arnoldi, Jakob; Chen, Xin

    2018-01-01

    The underdeveloped institutional framework and trade barriers between China’s provinces make cross-province acquisitions challenging. We explore how Chinese firms can mitigate this problem. Drawing on social network theory we propose that cross-province rotation of political leaders—a key element...... of the promotion system of political cadres in China—is a mechanism enabling growth through cross-province acquisitions. We conceptualize rotated leaders as brokers between two geographically dispersed networks. We contribute to the literature on the characteristics of Chinese social networks, the effect...... of political connections on firm strategy, and the impact of political rotations on firm growth in China’s provinces....

  10. Melilitites and associated alkaline silica-undersaturated rocks of the Vogtland/W-Bohemia (Germany/Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Abratis, M.; Viereck-Goette, L.; Ulrych, Jaromír; Munsel, D.

    2008-01-01

    Roč. 34, 4/6 (2008), s. 1325145-1325145 ISSN 0161-6951. [International Geological Congress /33./. 06.08.2008-14.08.2008, Oslo ] Institutional research plan: CEZ:AV0Z30130516 Keywords : melilitic rock, * Bohemian Massif, * Central European Cenozoic Igneous Province * W Bohemia * Vogtland Subject RIV: DB - Geology ; Mineralogy

  11. Rootless tephra stratigraphy and emplacement processes

    Science.gov (United States)

    Hamilton, Christopher W.; Fitch, Erin P.; Fagents, Sarah A.; Thordarson, Thorvaldur

    2017-01-01

    Volcanic rootless cones are the products of thermohydraulic explosions involving rapid heat transfer from active lava (fuel) to external sources of water (coolant). Rootless eruptions are attributed to molten fuel-coolant interactions (MFCIs), but previous studies have not performed systematic investigations of rootless tephrostratigraphy and grain-size distributions to establish a baseline for evaluating relationships between environmental factors, MFCI efficiency, fragmentation, and patterns of tephra dispersal. This study examines a 13.55-m-thick vertical section through an archetypal rootless tephra sequence, which includes a rhythmic succession of 28 bed pairs. Each bed pair is interpreted to be the result of a discrete explosion cycle, with fine-grained basal material emplaced dominantly as tephra fall during an energetic opening phase, followed by the deposition of coarser-grained material mainly as ballistic ejecta during a weaker coda phase. Nine additional layers are interleaved throughout the stratigraphy and are interpreted to be dilute pyroclastic density current (PDC) deposits. Overall, the stratigraphy divides into four units: unit 1 contains the largest number of sediment-rich PDC deposits, units 2 and 3 are dominated by a rhythmic succession of bed pairs, and unit 4 includes welded layers. This pattern is consistent with a general decrease in MFCI efficiency due to the depletion of locally available coolant (i.e., groundwater or wet sediments). Changing conduit/vent geometries, mixing conditions, coolant and melt temperatures, and/or coolant impurities may also have affected MFCI efficiency, but the rhythmic nature of the bed pairs implies a periodic explosion process, which can be explained by temporary increases in the water-to-lava mass ratio during cycles of groundwater recharge.

  12. Thallium isotope variations in an ore-bearing continental igneous setting: Collahuasi Formation, northern Chile

    Science.gov (United States)

    Baker, R. G. A.; Rehkämper, M.; Ihlenfeld, C.; Oates, C. J.; Coggon, R.

    2010-08-01

    Thallium is a highly incompatible element and a large fraction of the bulk silicate Earth Tl budget is, therefore, expected to reside in the continental crust. Nonetheless, the Tl isotope systematics of continental rocks are essentially unexplored at present. Here, we present new Tl isotope composition and concentration data for a suite of 36 intrusive and extrusive igneous rocks from the vicinity of porphyry Cu deposits in the Collahuasi Formation of the Central Andes in northern Chile. The igneous lithologies of the rocks are variably affected by the hydrothermal alteration that accompanied the formation of the Cu deposits. The samples display Tl concentrations that vary by more than an order of magnitude, from 0.1 to 3.2 μg/g, whilst ɛ 205Tl ranges between -5.1 and +0.1 (ɛ 205Tl is the deviation of the 205Tl/ 203Tl isotope ratio of a sample from a standard in parts per 10 4). These variations are primarily thought to be a consequence of hydrothermal alteration processes, including metasomatic transport of Tl, and formation/breakdown of Tl-bearing minerals, which are associated with small but significant Tl isotope effects. The Tl abundances show excellent correlations with both K and Rb concentrations but no co-variation with Cu. This demonstrates that Tl displays only limited chalcophile affinity in the continental crust of the Collahuasi Formation, but behaves as a lithophile element with a distribution that is primarily governed by partitioning of Tl + into K +-bearing phases. Collahuasi samples with propylitic alteration features, which are derived from the marginal parts of the hydrothermal systems, have, on average, slightly lighter Tl isotope compositions than rocks from the more central sericitic and argillic alteration zones. This small but statistically significant difference most likely reflects preferential retention of isotopically heavy Tl in alteration phases, such as white micas and clays, which formed during sericitic and argillic alteration.

  13. Plate tectonic influences on Earth's baseline climate: a 2 billion-year record

    Science.gov (United States)

    McKenzie, R.; Evans, D. A.; Eglington, B. M.; Planavsky, N.

    2017-12-01

    Plate tectonic processes present strong influences on the long-term carbon cycle, and thus global climate. Here we utilize multiple aspects of the geologic record to assess the role plate tectonics has played in driving major icehouse­-greenhouse transitions for the past 2 billion years. Refined paleogeographic reconstructions allow us to quantitatively assess the area of continents in various latitudinal belts throughout this interval. From these data we are able to test the hypothesis that concentrating continental masses in low-latitudes will drive cooler climates due to increased silicate weathering. We further superimpose records of events that are believed to increase the `weatherability' of the crust, such as large igneous province emplacement, island-arc accretion, and continental collisional belts. Climatic records are then compared with global detrital zircon U-Pb age data as a proxy for continental magmatism. Our results show a consistent relationship between zircon-generating magmatism and icehouse-greenhouse transitions for > 2 billion years, whereas paleogeographic records show no clear consistent relationship between continental configurations and prominent climate transitions. Volcanic outgassing appears to exert a first-order control on major baseline climatic shifts; however, paleogeography likely plays an important role in the magnitude of this change. Notably, climatic extremes, such as the Cryogenian icehouse, occur during a combination of reduce volcanism and end-member concentrations of low-latitudinal continents.

  14. Ring complexes and related rocks in Africa

    Science.gov (United States)

    Vail, J. R.

    Over 625 igneous complexes throughout Africa and Arabia have been selected and classified on the basis of petrographic association and chronology into six broad age groups forming 29 provinces. The groups range from Mid-Proterozoic to Tertiary and include gabbro, granite, syenite, foid syenite and carbonatite plutonic rocks, the majority in the form of ring-dykes, cone-sheets, plugs, circular intrusions, and their associated extrusive phases. Pan-African late or post-orogenic complexes (720-490 Ma) are common in the Arabian-Nubian and Tuareg shields of north Africa originating from subduction zone derived magmatism. Anorogenic complexes in Egypt, NE and central Sudan, Niger, Nigeria, Cameroon, Zaïre-Burundi, Malawi, Mozambique, Zimbabwe, Namibia and Angola span 550 to 50 Ma and are dominantly alkali granites and foid syenites. Many groups occur as en-echelon bands within linear arrays, and show migrating centres of intrusion in variable directions. In W. Africa there was a progressive shift of emplacement southwards during early Ordovician to Mid-Cretaceous times. Distribution patterns suggest thatdeep seated features, such as shear zones associated with lithospheric plate movements,controlled melting, and the resultant location of the complexes. Economic mineralization is not widespread in the rocks of the African ring complexes and is mainly restricted to small deposits of Sn, W, F, U and Nb.

  15. The offshore disposal of radioactive waste by drilled emplacement: A feasibility study

    International Nuclear Information System (INIS)

    Bury, M.R.C.

    1985-01-01

    This book is a report, based on a study by Taylor Woodrow Construction Limited, on the overall feasibility of the disposal of high-level radioactive waste in boreholes drilled deep into the ocean bed. The work comprises an engineering appraisal of the disposal process with a view to establishing technical and operational feasibility and providing overall cost information to enable an economic assessment to be made. Contents: Summary report; Reference criteria; Drilling operation; Transfer of radioactive waste, personnel and other supplies; Handling of radioactive waste on board; Lowering strings of canisters; Emplacement and backfilling of canisters; Preliminary design of marine platform; Retrieval of flasks or canisters lost or misplaced; Variations to the features of the lowering system; Logistics of the operation; Construction cost estimate; Operational costs; Appendix

  16. Endeavor research into evolving paradigms around ophiolites: the case of the oceanic igneous complexes of Costa Rica

    International Nuclear Information System (INIS)

    Alvarado, Guillermo E.; Denyer, Perci; Gazel, Esteban

    2009-01-01

    Studies on the radiolarite igneous (ophiolitic) complexes were done for more than one century in Costa Rica that range from Jurassic to Eocene. These studies can be grouped in four stages of knowledge: 1) from 1904 to 1957 were recognized the cherts, and the mafic and ultramafic igneous complexes, the first regional maps were done, and the first time were recognized ellipsoidal basalts, now widely known as pillow lavas. 2) From 1958 to 1978 the complexes were seen under the concept of the association of ophiolites (serpentine, gabbro, diabase, basalts, and related rocks) and interpreted the radiolarites as deep-sea sediments. The stage is characterized by the seminal work of Gabriel Dengo and by the first geochemical analyses in the framework of the plate tectonics. 3) A huge amount of geochemical data, paleontological and K/Ar ages were published from 1979 to 1994 and it was the stage of more controversial papers, their interpretation varied for the same locality (i.e. (Nicoya Peninsula) from relative simple stratigraphic model to a very complex nappe slices, and from a simple tectonic evolution (in situ and formed by a mid oceanic ridge volcanism) to a multistage evolution (terrains, and mid oceanic ridge, aseismic ridge, intraplate and island arc volcanism). The situation was similar in the other Costa Rican oceanic complexes. 4) The outlook for 1995 to the present it has been clarified and mutual agreement between the different groups. The stage is characterized by joint collaboration, the use of modern laboratory techniques as Sr, Nd, and Pb isotopes, major, trace and complete rare earth elements. 40A r/ 39 Ar dating, and volcanological criteria, together with detailed field mapping. The main new result of these studies was that the radiolarites (164-84 Ma) in the Nicoya Peninsula were significatively older than the basic igneous rocks (140-84 Ma), indicating a complex magmatic event intruding and erupting into the thick sedimentary sequence. For other areas

  17. An Attempt to Construction of Seismotectonic Province Map

    International Nuclear Information System (INIS)

    Noh, Myung Hyun; Shim, Taek Mo

    2010-01-01

    A seismotectonic province is a kind of seismic source where, in general, seismic characteristics are assumed to be uniform. It is different from earthquake-generating geological structures such as faults or folds. It is an area or a zone where earthquakes diffusely occur but no specific geological structure is identified to be responsible for those earthquakes. The terminology, a seismotectonic province is originated from a tectonic province of U.S. federal code, with emphasis on earthquakes. The seismotectonic province is called the seismogenic source in the regulatory guides of U.S. Nuclear Regulatory Commission (NRC), and the zone of diffuse seismicity in a guide of International Atomic Energy Agency (IAEA). In Korea, existing seismotectonic province maps were constructed based on the geological information due to insufficient earthquake data. As understood in its name, however, a seismotectonic province map should be based on the seismic information. Moreover, it should be noted that the Korean (geologic) tectonic structures cannot correctly represent the current tectonic regime because they were formed before the Cenozoic. In this context, we attempted to construct a seismotectonic province map by using seismic and geophysical information as well as geologic information

  18. Conditions for the test emplacement of intermediate-level radioactive wastes in chamber 8a of the 511 m level of the Asse Salt Mine

    International Nuclear Information System (INIS)

    1984-01-01

    The Gesellschaft fuer Strahlen- und Umweltforschung mbH (GSF) emplaces intermediate-level radioactive wastes which accumulate in an activity involving the use of radioactive materials that is licensed or reported in the Federal Republic of Germany or which are stored on an interim basis by the appropriate licensing or inspection agencies in chamber 8a of the 511 m level of the Asse Salt Mine in Remlingen near Wolfenbuettel in conjunction with an engineering test program. The type and form of the intermediate-level wastes must conform to certain conditions so that there are no hazards to personnel and the repository during transfer and subsequent storage. It is therefore necessary for the radioactive wastes to be treated and packaged before delivery in such a way that they satisfy the conditions presented in this document. The GSF shall inform the companies and organizations delivering wastes about its experiences with emplacement operations. The Conditions for the Test Emplacement of Intermediate-Level Radioactive Wastes in Chamber 8a of the 511 m Level of the Asse Salt Mine must be adapted to conform to the latest state of science and the art. The GSF must therefore reserve the right to modify the conditions, allowing for an appropriate transition period

  19. Detrital zircon and igneous protolith ages of high-grade metamorphic rocks in the Highland and Wanni Complexes, Sri Lanka: Their geochronological correlation with southern India and East Antarctica

    Science.gov (United States)

    Kitano, Ippei; Osanai, Yasuhito; Nakano, Nobuhiko; Adachi, Tatsuro; Fitzsimons, Ian C. W.

    2018-05-01

    The high-grade metamorphic rocks of Sri Lanka place valuable constraints on the assembly of central parts of the Gondwana supercontinent. They are subdivided into the Wanni Complex (WC), Highland Complex (HC) and Vijayan Complex (VC), but their correlation with neighbouring Gondwana terranes is hindered by a poor understanding of the contact between the HC and WC. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb dating of remnant zircon cores from 45 high-grade metamorphic rocks in Sri Lanka reveals two domains with different age characteristics that correlate with the HC and WC and which help constrain the location of the boundary between them. The HC is dominated by detrital zircon ages of ca. 3500-1500 Ma from garnet-biotite gneiss, garnet-cordierite-biotite gneiss, some samples of garnet-orthopyroxene-biotite gneiss and siliceous gneiss (interpreted as paragneisses) and igneous protolith ages of ca. 2000-1800 Ma from garnet-hornblende-biotite gneiss, other samples of garnet-orthopyroxene-biotite gneiss, garnet-two-pyroxene granulite, two-pyroxene granulite and charnockite (interpreted as orthogneisses). In contrast, the WC is dominated by detrital zircon ages of ca. 1100-700 Ma from paragneisses and igneous protolith ages of ca. 1100-800 Ma from orthogneisses. This clearly suggests the HC and WC have different origins, but some of our results and previous data indicate their spatial distribution does not correspond exactly to the unit boundary proposed in earlier studies using Nd model ages. Detrital zircon and igneous protolith ages in the HC suggest that sedimentary protoliths were eroded from local 2000-1800 Ma igneous rocks and an older Paleoproterozoic to Archean craton. In contrast, the WC sedimentary protoliths were mainly eroded from local late Mesoproterozoic to Neoproterozoic igneous rocks with very minor components from an older 2500-1500 Ma craton, and in the case of the WC precursor sediments there was possibly

  20. Uranium provinces and the exploration industry

    International Nuclear Information System (INIS)

    Hunter, J.; Michie, U.McL.

    1988-01-01

    There is little doubt that exploration by mining companies in established districts or 'provinces' has led to the discovery of substantial additional ore reserves. However, the competition for, and expenses of, land acquisitions in these known districts often prompts companies to search further afield. In some cases, new discoveries can merely be regarded as extensions of known provinces while others are located in completely new areas. Whether the explorers utilized concepts of metallogenic provinces in the course of such discoveries is questionable; rather, they would have sought the particular combinations of geological circumstances required by the model. Once a new deposit is found, however, the concept of a province, whether correct in that situation or not, is usually responsible for stimulating further activity. Recent examples of such behaviour are the Arizona Strip and NE Nebraska (USA) in provincial extensions and Roxby Downs, Lone Gull (NW Territories, Australia) and Lagoa Real (Brazil) in new areas. More routine and scientific application of metallogenic province theory by the uranium exploration industry would require evidence that not only the bulk of the world's uranium reserves but also the majority of the individual world-class deposits fall into geologically definable provinces. Such evidence should include the demonstration that particular areas of the Earth's crust had been enriched in uranium (with or without related elements) and that this enrichment had persisted through periods of crustal reworking and been responsible for concentrations of the metal ore deposits. The evidence described in the volume is critically reviewed in this context. (author). Refs, 4 figs

  1. Emplacement of pillow lavas from the ~ 2.8 Ga Chitradurga Greenstone Belt, South India: A physical volcanological, morphometric and geochemical perspective

    Science.gov (United States)

    Duraiswami, Raymond A.; Inamdar, Mustaqueem M.; Shaikh, Tahira N.

    2013-08-01

    The physical volcanology and morphometric analyses of pillowed lava flows from the Chitradurga basin of Chitradurga Greenstone Belt, South India have been undertaken. In the Chitradurga hills individual pillowed flows alternate with massive submarine sheet flows. The pillows from such flows are separated by chert and occur as spheroidal, elongated or reniform units that are devoid of vesicles, vesicle bands or pipe vesicles. The Mardihalli flow is exposed as a small elongated mound in the basin and consists of a massive core that is draped by pillows along the flow crest and flanks. The pillows from Mardihalli occur as spheroidal to elongate units with smooth, spalled or wrinkled surfaces with vesicular interiors. Repeated budding of larger pillows have produced a series of interconnected pillow units indicating fluid lava that was emplaced on steeply dipping flanks. Based on the morphological features the pillowed flows from the Chitradurga basin were emplaced at low effusion rates (≤ 5 m3/s). Pillows in these flows formed from low viscosity lavas that underwent negligible to moderate inflation due to rapid chilling. Sporadic occurrences of pillow breccias, hyaloclastite and chert breccias in the pillowed flow fields indicate disruption of pillows due to lava surges and slumping. It is envisaged that the Chitradurga basin witnessed distinct episodes of submarine tholeiite eruptions that produced pillowed lavas that variably interacted with sea water to produce geochemistries. The field and stratigraphic relationships of the volcanics and associated clastic sediments suggest that the pillow lavas were emplaced in a shallow marine marginal inter/back arc basin.

  2. Nd isotopes, U-Pb single grain and SHRIMP zircon ages from basement rocks of the Tocantin Province

    International Nuclear Information System (INIS)

    Fuck, R.A.; Dantas, E.L.; Pimentel, M.M.; Junges, S.L.; Moraes, R

    2001-01-01

    , which were interpreted as minimum ages of the igneous protoliths. Here we present a preliminary Nd isotope survey on basement gneiss and associated rocks sampled along a transect from Arraias to Porto Nacional, Tocantins. Single zircon U-Pb determinations and two SHRIMP U-Pb zircon ages are also presented. This study aims to assess the ages of rocks and sources involved in the continental crust generation of the northern segment of the Tocantins Province. The main goal is to identify different geochronologic provinces or crustal blocks and provide age constraints on the timing of crustal evolution recorded in the basement gneiss. U-Pb single crystal zircon and Sm-Nd whole rock isotopic analyses were carried out at the geochronology laboratory, Universidade de Brasilia. SHRIMP analyses were performed at Australian National University, Canberra (au)

  3. Journal of Earth System Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Volcanism; lava; Kilauea; Hawaii; Deccan; flood basalt. ... emplacement of the modern and active lava flows of Kilauea volcano in Hawaii, and based ... Bulk eruption rates for the Deccan province are unknown, and were probably high, but the ...

  4. Nornahraun lava morphology and mode of emplacement

    Science.gov (United States)

    Pedersen, Gro B. M.; Höskuldsson, Armann; Riishuus, Morten S.; Jónsdóttir, Ingibjörg; Gudmundsson, Magnús T.; Sigmundsson, Freysteinn; Óskarsson, Birgir V.; Drouin, Vincent; Gallagher, Catherine; Askew, Rob; Moreland, William M.; Dürig, Tobias; Dumont, Stephanie; Þórdarson, Þór

    2015-04-01

    The ongoing Nornahraun eruption is the largest effusive eruption in Iceland since the Laki eruption in 1783-84, with an estimated lava volume of ~1.15 km3 covering an area of ~83.4 km2 (as of 5 JAN 2015). The eruption provides an unprecedented opportunity to study i) lava morphologies and their emplacement styles, ii) the transition from from open to closed lava pathways and iii) lava pond formation. Tracking of the lava advancement and morphology has been performed by GPS and GoPro cameras installed in 4×4 vehicles as well as video footage. Complimentary observations have been provided from aircraft platforms and by satellite data. Of particular importance for lava morphology observations are 1-12 m/pixel airborne SAR images (x-band). The Nornahraun flow field comprises a continuum of morphologies from pāhoehoe to 'a'ā, which have varied tem-porally and spatially. At the onset of the eruption 31 AUG, lava flows advanced rapidly (400-800 m/hr) from the 1.5 km long fissure as large slabby pāhoehoe [1-3] sheet lobes, 100-500 m wide and 0.3-1 m thick at the flow fronts. By 1 SEPT, the flows began channeling towards the NE constrained by the older Holuhraun I lava field and the to-pography of flood plain itself. A central open channel developed, feeding a 1-2 km wide active 'a'ā frontal lobe that advanced 1-2 km/day. In addition to its own caterpillar motion, the frontal lobe advanced in a series of 30-50 m long breakouts, predominantly slabby and rubbly pāhoehoe [4,5]. These breakouts had initial velocities of 10-30 m/hr and reached their full length within tens of minutes and subsequently inflated over hours. With the continuous advancement of the 'a'ā flow front, the breakouts were incorporated into the 'a'ā flow fronts and seldom preserved. At the margins of the frontal lava lobe, the breakouts were more sporadic, but predominantly rubbly pāhoehoe and slabby pāhoehoe, as at the flow front. The lava flow advanced ENE into Jökulsá á Fjöllum on 7 SEPT

  5. Emplacement dynamics of phonolite magma into maar-diatreme structures - Correlation of field, thermal modeling and AMS analogue modeling data

    Czech Academy of Sciences Publication Activity Database

    Závada, Prokop; Dědeček, Petr; Mach, K.; Lexa, O.; Potužák, M.

    2011-01-01

    Roč. 201, č. 1-4 (2011), s. 210-226 ISSN 0377-0273 R&D Projects: GA MŠk ME09011; GA AV ČR KJB301110703 Institutional research plan: CEZ:AV0Z30120515 Keywords : phonolite * maar-diatreme * magma emplacement dynamics * thermal modeling * AMS analogue modeling * cavitation Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.978, year: 2011

  6. Structural Analysis of Silicic Lavas Reveals the Importance of Endogenous Flow During Emplacement

    Science.gov (United States)

    Andrews, G. D.; Martens, A.; Isom, S.; Maxwell, A.; Brown, S. R.

    2017-12-01

    Recent observations of silicic lava flows in Chile strongly suggest sustained, endogeneous flow beneath an insulating carapace, where the flow advances through breakouts at the flow margin. New mapping of vertical exposures around the margin of Obsidian Dome, California, has identified discreet lobe structures in cross-section, suggesting that flow-front breakouts occured there during emplacement. The flow lobes are identified through structural measurements of flow-banding orientation and the stretching directions of vesicles. Newly acquired lidar of the Inyo Domes, including Obsidian Dome, is being analyzed to better understand the patterns of folding on the upper surface of the lavas, and to test for fold vergence patterns that may distinguish between endogenous and exogenous flow.

  7. Constraining Controls on the Emplacement of Long Lava Flows on Earth and Mars Through Modeling in ArcGIS

    Science.gov (United States)

    Golder, K.; Burr, D. M.; Tran, L.

    2017-12-01

    Regional volcanic processes shaped many planetary surfaces in the Solar System, often through the emplacement of long, voluminous lava flows. Terrestrial examples of this type of lava flow have been used as analogues for extensive martian flows, including those within the circum-Cerberus outflow channels. This analogy is based on similarities in morphology, extent, and inferred eruptive style between terrestrial and martian flows, which raises the question of how these lava flows appear comparable in size and morphology on different planets. The parameters that influence the areal extent of silicate lavas during emplacement may be categorized as either inherent or external to the lava. The inherent parameters include the lava yield strength, density, composition, water content, crystallinity, exsolved gas content, pressure, and temperature. Each inherent parameter affects the overall viscosity of the lava, and for this work can be considered a subset of the viscosity parameter. External parameters include the effusion rate, total erupted volume, regional slope, and gravity. To investigate which parameter(s) may control(s) the development of long lava flows on Mars, we are applying a computational numerical-modelling to reproduce the observed lava flow morphologies. Using a matrix of boundary conditions in the model enables us to investigate the possible range of emplacement conditions that can yield the observed morphologies. We have constructed the basic model framework in Model Builder within ArcMap, including all governing equations and parameters that we seek to test, and initial implementation and calibration has been performed. The base model is currently capable of generating a lava flow that propagates along a pathway governed by the local topography. At AGU, the results of model calibration using the Eldgá and Laki lava flows in Iceland will be presented, along with the application of the model to lava flows within the Cerberus plains on Mars. We then

  8. Distribución óptima de carga en emplazamientos de generadores; Optimal charging distribution in emplacements of generators

    Directory of Open Access Journals (Sweden)

    Sergio de la Fé Dotres

    2014-04-01

    Full Text Available Incorporados al Sistema Eletroenergético Nacional funcionan emplazamientos de generación distribuida que representan más del 40 por ciento de la capacidad generadora instalada. Estos grupo utilizan fuel oil o diesel como combustibles por lo que lograr su explotación eficiente constituye una necesidad económica de primer orden. Se propone un instrumento computacional para lograr la mayor eficiencia en el uso del combustible mediante la distribución económica de las cargas y se desarrolla un método de optimización basado en el criterio del costo incremental del combustible para determinar el costo total de la generación del emplazamiento. Empleando un algoritmo genético simple se minimiza la función del costo mediante la asignación de las potencias a generar por cada máquina. Se comprueba la aplicabilidad del método mediante su aplicación a un emplazamiento específico. Por su rapidez y calidad de los resultados el instrumento computacional se recomienda para su explotación en emplazamientos y el despacho.  The emplacements of distributed generation that represent over the 40 percent of the generating installed capability work to the electric national system incorporated. These group Fuel Oil or diesel utilize like fuels for that achieving his efficient exploitation constitutes a need cheap to run first-rate. Distribution cheap to run of loads proposes a computational instrument to achieve the bigger efficiency in the use of intervening fuel itself and a method of optimization based in the opinion of the incremental cost of fuel to determine the total cost of the generation of the emplacement develops. Using a genetic algorithm the assignment of potencies minimizes the show of the intervening cost itself to generate for each machine. His application finds to a specific summons the applicability of the intervening method. For his rapidity and quality of results the computational instrument is recommended to exploitation in

  9. Erratum: Correction to: Emplacement controls for the basaltic-andesitic radial dikes of Summer Coon volcano and implications for flank vents at stratovolcanoes

    Science.gov (United States)

    Harp, A. G.; Valentine, G. A.

    2018-06-01

    In the article "Emplacement controls for the basaltic-andesitic radial dikes of Summer Coon volcano and implications for flank vents at stratovolcanoes", the vertical axis for Fig. 8 a was incorrectly labeled (i.e., the value for dikes per km2).

  10. In-situ detection of microbial life in the deep biosphere in igneous ocean crust

    Directory of Open Access Journals (Sweden)

    Everett Cosio Salas

    2015-11-01

    Full Text Available The deep biosphere is a major frontier to science. Recent studies have shown the presence and activity of cells in deep marine sediments and in the continental deep biosphere. Volcanic lavas in the deep ocean subsurface, through which substantial fluid flow occurs, present another potentially massive deep biosphere. We present results from the deployment of a novel in-situ logging tool designed to detect microbial life harbored in a deep, native, borehole environment within igneous oceanic crust, using deep ultraviolet native fluorescence spectroscopy. Results demonstrate the predominance of microbial-like signatures within the borehole environment, with densities in the range of 105 cells/mL. Based on transport and flux models, we estimate that such a concentration of microbial cells could not be supported by transport through the crust, suggesting in situ growth of these communities.

  11. In situ Detection of Microbial Life in the Deep Biosphere in Igneous Ocean Crust.

    Science.gov (United States)

    Salas, Everett C; Bhartia, Rohit; Anderson, Louise; Hug, William F; Reid, Ray D; Iturrino, Gerardo; Edwards, Katrina J

    2015-01-01

    The deep biosphere is a major frontier to science. Recent studies have shown the presence and activity of cells in deep marine sediments and in the continental deep biosphere. Volcanic lavas in the deep ocean subsurface, through which substantial fluid flow occurs, present another potentially massive deep biosphere. We present results from the deployment of a novel in situ logging tool designed to detect microbial life harbored in a deep, native, borehole environment within igneous oceanic crust, using deep ultraviolet native fluorescence spectroscopy. Results demonstrate the predominance of microbial-like signatures within the borehole environment, with densities in the range of 10(5) cells/mL. Based on transport and flux models, we estimate that such a concentration of microbial cells could not be supported by transport through the crust, suggesting in situ growth of these communities.

  12. Geologic-geochemical characteristics of Guidong granitic massif and recognition of geo-tectonic environment at the time of its emplacement

    Energy Technology Data Exchange (ETDEWEB)

    Jianhong, Li; Shanyuan, Wei; Mingyue, Feng [Beijing Research Inst. of Uranium Geology, Beijing (China); Liang, Liang [East China Inst. of Technology, Fuzhou (China)

    2004-11-01

    Based on the study of geologic characteristics, such as mineralogic assemblage, structural and textural features of granite of Guidong granitic massif, and by using petrochemical, trace-element and isotopic data, and some petrochemical, trace-element and isotopic diagrams widely applied to the identification of geo-tectonic environments, authors recognize that Guidong granitic massif was emplaced in post-orogenic collision environment. (authors)

  13. Petrology of the Miocene igneous rocks in the Altar region, main Cordillera of San Juan, Argentina. A geodynamic model within the context of the Andean flat-slab segment and metallogenesis

    Science.gov (United States)

    Maydagán, Laura; Franchini, Marta; Chiaradia, Massimo; Pons, Josefina; Impiccini, Agnes; Toohey, Jeff; Rey, Roger

    2011-07-01

    The Altar porphyry Cu-(Au-Mo) deposit (31° 29' S, 70° 28' W) is located in the Andean Main Cordillera of San Juan Province (Argentina), in the southern portion of the flat-slab segment (28-33°S), 25 km north of the world-class porphyry Cu-Mo deposits of Los Pelambres and El Pachón. Igneous rocks in the area have been grouped into the Early Miocene Lower Volcanic Complex -composed of intercalations of lava flows and thin volcaniclastic units that grade upwards to a thick massive tuff- and the Middle-Late Miocene Upper Subvolcanic Suite that consists of a series of porphyritic stocks and dikes and magmatic and hydrothermal breccias. The Lower Volcanic Complex represents an Early Miocene arc (20.8 Ma ± 0.3 Ma; U-Pb age) erupted over a steep subduction zone. Their magmas equilibrated with an assemblage consisting of plagioclase- and pyroxene-dominated mineral residues, and experienced fractional crystallization and crustal contamination procesess. Their radiogenic signatures are interpreted to indicate conditions of relatively thickened continental crust in Altar during the Early Miocene, compared to the south and west. The Upper Subvolcanic Suite represents the development of a Middle-Late Miocene arc (11.75 ± 0.24 Ma, 10.35 ± 0.32 Ma; U-Pb ages) emplaced over a shallow subduction zone. A magmatic gap in Altar area betwen the Lower Volcanic Complex and Upper Subvolcanic Suite correlates with documented higher rates of compression in this period, that may have favored the storage of the USS magmas in cameras within the crust. Magmas of the Upper Subvolcanic Suite require a hornblende-bearing residual mineral assemblage that is interpreted to reflect their higher water contents. The relatively uniform radiogenic isotope compositions of the Upper Subvolcanic Suite magmas suggest a homogeneously mixed crust-mantle contribution in the source region. They have similar REE signatures as other fertile intrusives of the flat-slab. The differences observed in their

  14. Magmatic and Crustal Differentiation History of Granitic Rocks from Hf-O Isotopes in Zircon

    Science.gov (United States)

    Kemp, , A. I. S.; Hawkesworth, , C. J.; Foster, , G. L.; Paterson, , B. A.; Woodhead, , J. D.; Hergt, , J. M.; Gray, , C. M.; Whitehouse, M. J.

    2007-02-01

    Granitic plutonism is the principal agent of crustal differentiation, but linking granite emplacement to crust formation requires knowledge of the magmatic evolution, which is notoriously difficult to reconstruct from bulk rock compositions. We unlocked the plutonic archive through hafnium (Hf) and oxygen (O) isotope analysis of zoned zircon crystals from the classic hornblende-bearing (I-type) granites of eastern Australia. This granite type forms by the reworking of sedimentary materials by mantle-like magmas instead of by remelting ancient metamorphosed igneous rocks as widely believed. I-type magmatism thus drives the coupled growth and differentiation of continental crust.

  15. Long-term, deep-mantle support of the Ethiopia-Yemen Plateau

    Science.gov (United States)

    Sembroni, Andrea; Faccenna, Claudio; Becker, Thorsten W.; Molin, Paola; Abebe, Bekele

    2016-04-01

    Ethiopia is a key site to investigate the interactions between mantle dynamics and surface processes because of the presence of the Main Ethiopian Rift (MER), Cenozoic continental flood basalt volcanism, and plateau uplift. The role of mantle plumes in causing Ethiopia's flood basalts and tectonics has been commonly accepted. However, the location and number of plumes and their impact on surface uplift are still uncertain. Here, we present new constraints on the geological and topographic evolution of the Ethiopian Plateau (NW Ethiopia) prior to and after the emplacement of the large flood basalts (40-20 Ma). Using geological information and topographic reconstructions, we show that the large topographic dome that we see today is a long-term feature, already present prior the emplacement of the flood basalts. We also infer that large-scale doming operated even after the emplacement of the flood basalts. Using a comparison with the present-day topographic setting we show that an important component of the topography has been and is presently represented by a residual, non-isostatic, dynamic contribution. We conclude that the growth of the Ethiopian Plateau is a long-term, probably still active, dynamically supported process. Our arguments provide constraints on the processes leading to the formation of one of the largest igneous plateaus on Earth.

  16. Potential uranium provinces in some arabian countries

    Energy Technology Data Exchange (ETDEWEB)

    Salman, A A [Nuclear materials authority, El Maadi, Cairo, (Egypt)

    1995-10-01

    This work represents an attempt to delineate potential uranium provinces in some Arabian countries using various related recognition criteria. Definition of these provinces is based on the available geologic and tectonic setting beside geochronological sequence and some geochemical characteristics. This trial would be of a great help for interchanging the ideas and necessary data for the development in the fields of uranium exploration and production. As a result of this study, a number of promising potential uranium provinces are recommended in some arabian countries. 5 figs.

  17. Potential uranium provinces in some arabian countries

    International Nuclear Information System (INIS)

    Salman, A.A.

    1995-01-01

    This work represents an attempt to delineate potential uranium provinces in some Arabian countries using various related recognition criteria. Definition of these provinces is based on the available geologic and tectonic setting beside geochronological sequence and some geochemical characteristics. This trial would be of a great help for interchanging the ideas and necessary data for the development in the fields of uranium exploration and production. As a result of this study, a number of promising potential uranium provinces are recommended in some arabian countries. 5 figs

  18. Evaluation of geothermal potential of Rio Grande rift and Basin and Range province, New Mexico. Final technical report, January 1, 1977-May 31, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Callender, J.F.

    1985-04-01

    A study was made of the geological, geochemical and geophysical characteristics of potential geothermal areas in the Rio Grande rift and Basin and Range province of New Mexico. Both regional and site-specific information is presented. Data was collected by: (1) reconnaissance and detailed geologic mapping, emphasizing Neogene stratigraphy and structure; (2) petrologic studies of Neogene igneous rocks; (3) radiometric age-dating; (4) geochemical surveying, including regional and site-specific water chemistry, stable isotopic analyses of thermal waters, whole-rock and mineral isotopic studies, and whole-rock chemical analyses; and (5) detailed geophysical surveys, using electrical, gravity and magnetic techniques, with electrical resistivity playing a major role. Regional geochemical water studies were conducted for the whole state. Integrated site-specific studies included the Animas Valley, Las Cruces area (Radium Springs and Las Alturas Estates), Truth or Consequences region, the Albuquerque basin, the San Ysidro area, and the Abiquiu-Ojo Caliente region. The Animas Valley and Las Cruces areas have the most significant geothermal potential of the areas studied. The Truth or Consequences and Albuquerque areas need further study. The San Ysidro and Abiquiu-Ojo Caliente regions have less significant geothermal potential. 78 figs., 16 tabs.

  19. The effects of weathering on the physical and mechanical properties of igneous and metamorphic saprolites

    DEFF Research Database (Denmark)

    Rocchi, Irene; Coop, M. R.; Maccarini, M.

    2017-01-01

    The present paper presents three extensive datasets of laboratory testing on weathered geomaterials, which are emblematic of soil types widely found worldwide. The overall dataset includes soils originating from igneous and metamorphic rocks, either coarse or fine grained and having either felsic...... or mafic minerals. In particular, the data are interpreted to highlight the effects that weathering has on the physical and mechanical properties of these natural geomaterials comparing them with published data with the aim to provide a general framework of interpretation that takes into account...... this geological process and links soil mechanics to engineering geology. Generally, weathering induces a reduction in the grain size, both due to physical actions (e.g. opening of grain contacts) and to the chemical decomposition of minerals resulting in the formation of clay minerals. As weathering proceeds...

  20. Pre-waste-emplacement ground-water travel time sensitivity and uncertainty analyses for Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Kaplan, P.G.

    1993-01-01

    Yucca Mountain, Nevada is a potential site for a high-level radioactive-waste repository. Uncertainty and sensitivity analyses were performed to estimate critical factors in the performance of the site with respect to a criterion in terms of pre-waste-emplacement ground-water travel time. The degree of failure in the analytical model to meet the criterion is sensitive to the estimate of fracture porosity in the upper welded unit of the problem domain. Fracture porosity is derived from a number of more fundamental measurements including fracture frequency, fracture orientation, and the moisture-retention characteristic inferred for the fracture domain

  1. An ethnobotanical survey on hormozgan province, Iran

    Directory of Open Access Journals (Sweden)

    Omid Safa

    2012-12-01

    Full Text Available Objective: The present study is based on an ethnobotanical research project conducted in Hormozgan province that is located in south of Iran, bordering waters of the Persian Gulf and Oman Sea. This survey was carried out in order to recover the ethnobotanical and ethnomedicinal knowledge of the residents of this province. They are using medicinal and functional plants for treating or preventing several diseases. Materials and Methods: Ethnobotanical data sheets were run with the native inhabitants and people of the province by arranging frequent field trips to different parts of the province and direct interviews with them especially those who were more familiar with the plants and their usage.Results: A total of 150 plant species belonging to 53 families were recorded for their ethnobotanical and ethnomedicinal uses among the people of province. The records were developed by scientific names, family names, local names, medicinal parts used, different ways of their application, and traditional uses of the plants. There was high compliance in the use of plants in painful disorders, gastrointestinal, and dermatological diseases.Conclusion: This study revealed that the people of Hormozgan province have a rich knowledge of natural resources. The use and consumption of medicinal plants are still important parts of their life. Rational use of native medicinal plants may benefit and improve their living standards and quality of life. The results of this study can be used as a basis for selecting herbs for further pharmacological, phytochemical, and pharmacognostical studies.

  2. A brief comparison of lava flows from the Deccan Volcanic Province ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    In this paper, we first present a short overview of important studies pertaining to the emplacement ... activity on the surface of the earth. They cover ... Of primary importance is the amount of .... recent developments in physical volcanology. Com-.

  3. Geochemical significance of neoproterozoic rasimalai alkali syenite emplaced along Dharmapuri shear zone in the Northern part of Tamil Nadu

    International Nuclear Information System (INIS)

    Thangavel, S.; Balasubramani, S.; Nagaraju, M.; Bhattacharya, D.; Zakaulla, Syed; Rai, A.K.

    2015-01-01

    The Rasimalai alkali syenite complex is emplaced within Peninsular Gneissic complex and spatially associated with NE-SW trending major Dharmapuri shear zone (DSZ) in the northern part of Tamil Nadu. It is surrounded by epidote hornblend egneiss, which is the fenetised product of Charnockite and occurs about 20 km NE of Alangayam in Vellore district. It is mainly comprised of medium to coarse grained grey syenite (albite and orthoclase) and medium to micro grained pink syenite (orthoclase, microcline and perthite) at places porphyritic in nature with hornblende, riebeckitc, aegirine and acmite as accessory minerals. Grey syenite is non radioactive and uranium mineralisation is associated with pink syenite (syngenetic and disseminated type) and quartz-barite veins (hydrothermal type). Hydrothermal activity is manifested in the form of pyrite, chalcopyrite, galena, barite, calcite and calcian-strontianite which occur in the form of disseminations, stringers, lumps, aggregates, veinlets and veins. Presence of high silica (63.14-75.43%) with high field strength elements (U, Th, Nb and Pb) and large ion lithophile elements (Rb, Sr, K, Ba) possibly indicates that Rasimalai alkali syenite is the product of crustal communication and partial melting of protracted emplacement of parental alkali basaltic magma

  4. Geomorphology of crater and basin deposits - Emplacement of the Fra Mauro formation

    Science.gov (United States)

    Morrison, R. H.; Oberbeck, V. R.

    1975-01-01

    Characteristics of continuous deposits near lunar craters larger than about 1 km wide are considered, and it is concluded that (1) concentric dunes, radial ridges, and braided lineations result from deposition of the collision products of ejecta from adjacent pairs of similarly oriented secondary-crater chains and are, therefore, concentrations of secondary-crater ejecta; (2) intracrater ridges are produced within preexisting craters surrounding a fresh primary crater by ricocheting and focusing of secondary-crater ejecta from the preexisting craters' walls; and (3) secondary cratering has produced many of the structures of the continuous deposits of relatively small lunar craters and is the dominant process for emplacement of most of the radial facies of the continuous deposits of large lunar craters and basins. The percentages of Imbrium ejecta in deposits and the nature of Imbrium sculpturing are investigated.

  5. Feasibility studies of air placed techniques as emplacement means of different backfilling materials in underground radioactive waste disposal

    International Nuclear Information System (INIS)

    Atabek, R.; Conche, P.; Lajudie, A.; Revertegat, E.

    1992-01-01

    Air placed techniques are likely to be used as emplacement means of different backfilling materials in underground waste repositories. A literature survey of the air placed techniques and equipments leads to the choice of the dry process taking into account the emplacement constraints (distance: 300 m, flow: 10 m 3 /h) and the large variety of materials to be placed. Tests performed in the case of cement-based materials (with and without addition of silica fumes), for different types of cement and as a function of the incidence of the jet, show that it is possible to put in place mortars of good quality. However heterogeneity in the material composition is found when the jet is stopped. This problem may be partly solved by a better automation of the process. Complementary tests, carried out with the preselected clay of Fourges Cahaignes, clearly demonstrate the ability of the air placed technique to put in place pure clay: a dry density of 1.50kg/m 3 is reached in the case of coarse material and for a final water content of 30% (in weight). Feasibility tests performed on clay-sand mixtures are not conclusive due to an unappropriate granulometry distribution of the sand. 11 figs., 9 tabs

  6. Growth of plutons by incremental emplacement of sheets in crystal-rich host: Evidence from Miocene intrusions of the Colorado River region, Nevada, USA

    Science.gov (United States)

    Miller, C.F.; Furbish, D.J.; Walker, B.A.; Claiborne, L.L.; Koteas, G.C.; Bleick, H.A.; Miller, J.S.

    2011-01-01

    Growing evidence supports the notion that plutons are constructed incrementally, commonly over long periods of time, yet field evidence for the multiple injections that seem to be required is commonly sparse or absent. Timescales of up to several million years, among other arguments, indicate that the dominant volume does not remain largely molten, yet if growing plutons are constructed from rapidly solidifying increments it is unlikely that intrusive contacts would escape notice. A model wherein magma increments are emplaced into melt-bearing but crystal-rich host, rather than either solid or crystal-poor material, provides a plausible explanation for this apparent conundrum. A partially solidified intrusion undoubtedly comprises zones with contrasting melt fraction and therefore strength. Depending on whether these zones behave elastically or ductilely in response to dike emplacement, intruding magma may spread to form sheets by either of two mechanisms. If the melt-bearing host is elastic on the relevant timescale, magma spreads rather than continuing to propagate upward, where it encounters a zone of higher rigidity (higher crystal fraction). Similarly, if the dike at first ascends through rigid, melt-poor material and then encounters a zone that is weak enough (poor enough in crystals) to respond ductilely, the ascending material will also spread because the dike tip ceases to propagate as in rigid material. We propose that ascending magma is thus in essence trapped, by either mechanism, within relatively crystal-poor zones. Contacts will commonly be obscure from the start because the contrast between intruding material (crystal-poorer magma) and host (crystal-richer material) is subtle, and they may be obscured even further by subsequent destabilization of the crystal-melt framework. Field evidence and zircon zoning stratigraphy in plutons of the Colorado River region of southern Nevada support the hypothesis that emplacement of magma replenishments into a

  7. The Manihiki Plateau—a key to missing hotspot tracks?

    Science.gov (United States)

    Pietsch, R.; Uenzelmann-Neben, G.

    2016-08-01

    A Neogene magmatic reactivation of the Manihiki Plateau, a large igneous province (LIP) in the central Pacific, is studied using seismic reflection data. Igneous diapirs have been identified exclusively within a narrow WNW-ESE striking corridor in the southern High Plateau (HP), which is parallel to the Neogene Pacific Plate motion and overlaps with an extrapolation of the Society Islands Hotspot (SIH) path. The igneous diapirs are characterized by a narrow width (>5 km), penetration of the Neogene sediments, and they become progressively younger towards the East (23-10 Ma). The magmatic source appears to be of small lateral extent, which leads to the conclusion that the diapirs represent Neogene hotspot volcanism within a LIP, and thus may be an older, previously unknown extension of the SIH track (>4.5 Ma). Comparing hotspot volcanism within oceanic and continental lithosphere, we further conclude that hotspot volcanism within LIP crust has similarities to tectonically faulted continental crust.

  8. Terrestrial acidification during the end-Permian biosphere crisis?

    NARCIS (Netherlands)

    Sephton, Mark A.; Jiao, Dan; Engel, Michael H.; Looy, Cindy V.; Visscher, Henk

    Excessive acid rainfall associated with emplacement of the Siberian Traps magmatic province is increasingly accepted as a major contributing factor to the end-Permian biosphere crisis. However, direct proxy evidence of terrestrial acidification is so far not available. In this paper, we seek to

  9. Review of and contribution to the Stratigraphy of the Cenozoic Igneous Rocks in the Republic of Yemen

    International Nuclear Information System (INIS)

    El-Nakhal, H.A.

    2002-01-01

    In Yemen the Cenozoic igneous rocks consists of intrusive and extrusive rocks with interlayered sediments, all of which are included within the Manakha Group (latest Cretaceous-Holocene). This group is subdivided into the Haraz Formation which includes the latest Cretaceous-Tertiary volcanics and the interlayered sediments, the Aden Formation which includes the Late Tertiary-Holocene volcanics, and the Bura Formations are introduced here as new units. The Haraz Formation replaces the informal names: Trap Series, Yemen Volcanics and Aden Trap Series, Yemen Volcanics and Adan Trap Series.The Adan Formation are a readaptation of the term Aden Vocanic Series. A startotype for the Aden Formation is designated in the Shuqra-Ahwar area. (author)

  10. Cogeneration opportunities in the maritime provinces

    International Nuclear Information System (INIS)

    MacPherson, S.W.

    1999-01-01

    With the arrival of natural gas in New Brunswick in November 1999, the province will be faced with new power generation development opportunities in four different categories of power projects. These include industrial self generation (including cogeneration), merchant power plants, power projects to replace aging facilities, and power projects to help meet future environmental needs. New Brunswick's competitive advantage in harnessing the power generation development opportunities lies in the fact that it is close to major electricity markets in Quebec and New England. It also has many available generation sites. The province's many pulp and paper plants with large process steam needs are also ideal candidates for cogeneration. Some of the major competitive advantages of natural gas over coal are its lower operation and maintenance costs, it is thermally more efficient, produces lower emissions to the environment and prices are competitive. One of the suggestions in New Brunswick Power's new restructuring proposal is to unbundle electricity service in the province into generation and transmission and distribution services. Three gas-fired projects have already been proposed for the province. The 284 MW Bayside Power Project at the Courtenay Bay Generating Station is the most advanced

  11. Early Jurassic clay authigenesis in the Central Appalachian Valley and Ridge province; infiltration of surface-derived fluids during Pangean rifting

    Science.gov (United States)

    Lynch, E. A.; van der Pluijm, B.; Vennemann, T. W.

    2017-12-01

    The eastern margin of North America has a protracted and intricate tectonic history. The terminal collision of Gondwana and Laurentia in the late Paleozoic formed the Appalachian mountain belt, a trans-continental orogen that persisted for almost 100 million years until Mesozoic break-up of the supercontinent Pangea. A host of studies have targeted the evolution and migration of fluids through Appalachian crust in an effort to understand how fluid promotes mass and heat redistribution, and mediates crustal deformation, particularly during the assembly of Pangea. Folded clay units from the Central Appalachian Valley and Ridge province were sampled for stable and radiogenic isotope analysis. Separation of samples into different grain-size fractions characterizes detrital (host) and authigenic (neomineralized) clays. Stable H-isotope compositions reveal a systematic pattern with varying proportions of illite polytypes—the finer, younger fraction is D-depleted compared to the coarser, primarily detrital fraction. For each individual location, the H-isotopic composition of the fluid from which the authigenic population was grown is calculated. δDVSMOW of these fluids has a range from -77 to -52 ± 2 ‰, consistent with a surface-derived fluid source. The notably negative values for several samples indicates a meteoric composition of moderate to high elevation origin, suggesting that they are not connate waters, but instead preserve infiltration of fluids due to fracture-induced permeability. Key to this interpretation is 40Ar/39Ar-dating of a subset of these samples that reveals a post-orogenic age for authigenic clay mineralization in the Early Jurassic ( 180 Ma). These ages are evidence that surface fluid infiltration was unrelated to the Appalachian orogeny, but coeval with (upper) crustal extension from the initial break-up of Pangea and the emplacement of the Central Atlantic Magmatic Province.

  12. Geothermal constraints on Emeishan mantle plume magmatism: paleotemperature reconstruction of the Sichuan Basin, SW China

    Science.gov (United States)

    Zhu, Chuanqing; Hu, Shengbiao; Qiu, Nansheng; Jiang, Qiang; Rao, Song; Liu, Shuai

    2018-01-01

    The Middle-Late Permian Emeishan Large Igneous Province (ELIP) in southwestern China represents a classic example of a mantle plume origin. To constrain the thermal regime of the ELIP and contemporaneous magmatic activity in the northeastern Sichuan Basin, maximum paleotemperature profiles of deep boreholes were reconstructed using vitrinite reflectance (Ro) and apatite fission track data. Two heating patterns were identified: (1) heating of the overlying lithosphere by magma storage regions and/or magmatic activity related to the mantle plume, which resulted in a relatively strong geothermal field and (2) direct heating of country rock by stock or basalt. Borehole Ro data and reconstructed maximum paleotemperature profiles near the ELIP exhibit abrupt tectonothermal unconformities between the Middle and Late Permian. The profiles in the lower subsections (i.e., pre-Middle Permian) exhibited significantly higher gradients than those in the upper subsections. Distal to the basalt province, high paleo-geotemperatures (hereafter, paleotemperatures) were inferred, despite deformation of the paleogeothermal curve due to deep faults and igneous rocks within the boreholes. In contrast, Ro profiles from boreholes without igneous rocks (i.e., Late Permian) contained no break at the unconformity. Paleotemperature gradients of the upper and the lower subsections and erosion at the Middle/Late Permian unconformity revealed variations in the thermal regime. The inferred spatial distribution of the paleothermal regime and the erosion magnitudes record the magmatic and tectonic-thermal response to the Emeishan mantle plume.

  13. A preserved early Ediacaran magmatic arc at the northernmost portion of the Transversal Zone central subprovince of the Borborema Province, Northeastern South America

    Directory of Open Access Journals (Sweden)

    Benjamim Bley de Brito Neves

    Full Text Available ABSTRACT: Magmatic arcs are an essential part of crust-forming events in planet Earth evolution. The aim of this work was to describe an early Ediacaran magmatic arc (ca. 635-580 Ma exposed in the northernmost portion of the Transversal Zone, central subprovince of Borborema Province, northeast Brazil. Our research took advantage of several syntheses by different authors, including theses and dissertations, carried out on magmatic rocks of the study area for the last 30 years. The ca. 750 km long and up to 140 km wide arc, trending ENE-WSW, is preserved to the south of the Patos Lineament, between 35º15' and 42º30'W and 7º15' and 8ºS. About 90 different stocks and batholiths of I-type granitic rocks were mapped along this orogenic zone, preferentially intruding low-grade schists of the Cryogenian-Ediacaran Piancó-Alto Brígida (SPAB belt. Three igneous supersuites are recognized: a epidote-bearing granodiorites and tonalites ("Conceição" type; b high-K calc-alkaline granites ("Itaporanga" type; c biotite granodiorites of trondhjemite affinity ("Serrita" type. A fourth group of peralkalic and shoshonitic rocks occurs to the south of the previous ones, reflecting special tectonic conditions. NNE-SSW trending Paleoproterozoic fold belts, surrounding Archean nuclei, characterize the continental part of the northern lower plate. The oceanic fraction of this lower plate was recycled by subduction and scarce remnants of which may be seen either within the enclosing low-grade schists or as xenoliths within the arc intrusions. The upper continental plate presents WSW-ENE structural trends and is composed of Neoproterozoic fold belts and Paleoproterozoic reworked basement inliers. Available data bear clear evidence of an Ediacaran magmatic arc built at the northern portion of the Transversal Zone in the Borborema Province, northeast Brazil.

  14. Field test demonstration of emplacement feasibility of precompacted clay buffer materials in a granitic medium

    International Nuclear Information System (INIS)

    Jorda, M.; Lajudie, A.; Gatabin, C.; Atabek, R.

    1992-01-01

    Field test demonstration of emplacement feasibility of precompacted clay buffer materials in a granitic medium has been successfully carried out in February 1990 at the mining centre of FANAY. SILORD site was selected allowing the drilling through the 'Raise Boring' technique of pits of 30 m depth minimum between two pre-existent galleries. Two pits of 37 m depth were drilled and characterized in detail: mean diameter and vertical deviation measurements, valuation of the surface condition (rugosity) and cracking. The pit which was the most regular was selected for the feasibility test it-self. In parallel, manufacturing and handling techniques for the engineered barrier were improved. The bricks were made from a powdered mixture of clay and 10% sand and formed the barrier which was installed in the pit using iron baskets. The technique used was compacting by uniaxial pressing at 64 MPa. Twenty eight baskets containing the engineered barrier were fabricated at LIBOS (refractory manufactory of CTE Group) and taken to FANAY-SILORD. A maximal diameter of 96.03 cm was determined for the basket passing through (basket height = 1.335 m) and verified by the lowering of basket gauges in the pit. The baskets were stacked up in the pit, without any difficulty, with a mean radial gap of 1.6 cm (for a pit mean diameter of 99.3 cm). Three simulated COGEMA waste containers were then satisfactorily installed. The real volume to be sealed, including residual voids, was estimated at 21.47 m 3 . The engineered barrier weight after emplacement came to 36280 kg leading to a dry density in service, i.e. after the engineered barrier swelling, of 1.69. 30 figs

  15. Magnetotelluric Investigations of the Yellowstone Caldera: Understanding the Emplacement of Crustal Magma Bodies

    Science.gov (United States)

    Gurrola, R. M.; Neal, B. A.; Bennington, N. L.; Cronin, R.; Fry, B.; Hart, L.; Imamura, N.; Kelbert, A.; Bowles-martinez, E.; Miller, D. J.; Scholz, K. J.; Schultz, A.

    2017-12-01

    Wideband magnetotellurics (MT) presents an ideal method for imaging conductive shallow magma bodies associated with contemporary Yellowstone-Snake River Plain (YSRP) magmatism. Particularly, how do these magma bodies accumulate in the mid to upper crust underlying the Yellowstone Caldera, and furthermore, what role do hydrothermal fluids play in their ascent? During the summer 2017 field season, two field teams from Oregon State University and the University of Wisconsin-Madison installed forty-four wideband MT stations within and around the caldera, and using data slated for joint 3-D inversion with existing seismic data, two 2-D vertical conductivity sections of the crust and upper mantle were constructed. These models, in turn, provide preliminary insight into the emplacement of crustal magma bodies and hydrothermal processes in the YSRP region.

  16. Emplacement, petrological and magnetic susceptibility characteristics of diverse magmatic epidote-bearing granitoid rocks in Brazil, Argentina and Chile

    Science.gov (United States)

    Sial, A. N.; Toselli, A. J.; Saavedra, J.; Parada, M. A.; Ferreira, V. P.

    1999-03-01

    Magmatic epidote (mEp)-bearing granitoids from five Neoproterozoic tectonostratigraphic terranes in Northeastern (NE) Brazil, Early Palaeozoic calc-alkalic granitoids in Northwestern (NW) Argentina and from three batholiths in Chile have been studied. The elongated shape of some of these plutons suggests that magmas filled fractures and that dyking was probably the major mechanism of emplacement. Textures reveal that, in many cases, epidote underwent partial dissolution by host magma and, in these cases, may have survived dissolution by relatively rapid upward transport by the host magma. In plutons where such a mechanism is not evident, unevenly distributed epidote at outcrop scale is armoured by biotite or near-solidus K-feldspar aggregates, which probably grew much faster than epidote dissolution, preventing complete resorption of epidote by the melt. Al-in-hornblende barometry indicates that, in most cases, amphibole crystallized at P≥5 kbar. Kyanite-bearing thermal aureoles surrounding plutons that intruded low-grade metamorphic rocks in NE Brazil support pluton emplacement at intermediate to high pressure. mEp show overall chemical variation from 20 to 30 mol% (mole percent) pistacite (Ps) and can be grouped into two compositional ranges: Ps 20-24 and Ps 27-30. The highest Ps contents are in epidotes of plutons in which hornblende solidified under Pcorrosion of individual epidote crystals included in plagioclase in high-K calc-alkalic granitoids in NE Brazil, emplaced at 5-7 kbar pressure, yielded estimates of magma transport rate from 70 to 350 m year -1. Most of these plutons lack Fe-Ti oxide minerals and Fe +3 is mostly associated with the epidote structure. Consequently, magnetic susceptibility (MS) in the Neoproterozoic granitoids in NE Brazil, as well as Early Palaeozoic plutons in Argentina and Late Palaeozoic plutons in Chile, is usually low (3.0×10 -3 SI, typical of magnetite-series granitoids crystallized under higher oxygen fugacity. In NE

  17. Subduction history of the Paleo-Pacific plate beneath the Eurasian continent: Evidence from Mesozoic igneous rocks and accretionary complex in NE Asia

    Science.gov (United States)

    Xu, W.

    2015-12-01

    Mesozoic magmatisms in NE China can be subdivided into seven stages, i.e., Late Triassic, Early Jurassic, Middle Jurassic, Late Jurassic, early Early Cretaceous, late Early Cretaceous, and Late Cretaceous. Late Triassic magmatisms consist of calc-alkaline igneous rocks in the Erguna Massif, and bimodal igneous rocks in eastern margin of Eurasian continent. The former reveals southward subduction of the Mongol-Okhotsk oceanic plate, the latter reveals an extensional environment (Xu et al., 2013). Early Jurassic magmatisms are composed of calc-alkaline igneous rocks in the eastern margin of the Eurasian continent and the Erguna Massif, revealing westward subduction of the Paleo-pacific plate and southward subduction of the Mongol-Okhotsk oceanic plate (Tang et al., 2015), respectively. Middle Jurassic magmatism only occur in the Great Xing'an Range and the northern margin of the NCC, and consists of adakitic rocks that formed in crustal thickening, reflecting the closure of the Mongol-Okhotsk ocean (Li et al., 2015). Late Jurassic and early Early Cretaceous magmatisms only occur to the west of the Songliao Basin, and consist of trackyandesite and A-type of rhyolites, revealing an extensional environment related to delamination of thickened crust. The late Early Cretaceous magmatisms are widespread in NE China, and consist of calc-alkaline volcanics in eastern margin and bimodal volcanics in intracontinent, revealing westward subduction of the Paleo-pacific plate. Late Cretaceous magmatisms mainly occur to the east of the Songliao Basin, and consist of calc-alkaline volcanics in eastern margin and alkaline basalts in intracontinent (Xu et al., 2013), revealing westward subduction of the Paleo-pacific plate. The Heilongjiang complex with Early Jurassic deformation, together with Jurassic Khabarovsk complex in Russia Far East and Mino-Tamba complex in Japan, reveal Early Jurassic accretionary history. Additionally, the Raohe complex with the age of ca. 169 Ma was

  18. Operational procedures for receiving, packaging, emplacing, and retrieving high-level and transuranic waste in a geologic repository in TUFF

    International Nuclear Information System (INIS)

    Dennis, A.W.; Mulkin, R.

    1984-01-01

    The Nevada Nuclear Waste Storage Investigations Project, directed by the Nevada Operations Office of the Department of Energy, is currently developing conceptual designs for a commercial nuclear waste repository. In this paper, the preliminary repository operating plans are identified and the proposed repository waste inventory is discussed. The receipt rates for truck and rail car shipments of waste are determined as are the required repository waste emplacement rates

  19. The Brazil-Angola alkaline - carbonatite province and its main economic aspects

    International Nuclear Information System (INIS)

    Loureiro, F.E.V.L.; Di Valderano, M.H.W.

    1982-01-01

    The principal characteristics of the Brazil-Angola Alkaline Carbonatite Province are defined and described with specific reference to tectonic setting and economic aspects. The economic aspects of the Brazilian uranium deposits are emphasised. The Brazil-Angola Alkaline-Carbonatite Province can be divided into six Brazilian sub-provinces and two Angolan sub-provinces. Correlation between the sub-provinces of Brazil and Angola remains speculative due to the lack of detailed information, especially age determinations on the Angolan rocks. However, an analysis of the tectonic and petrochemical aspects suggests that the two Brazilian sub-provinces situated along the littoral of Rio de Janeiro/ Sao Paulo and around the periphery of the Parana Basin may be more easily comparable to the two Angolan sub-provinces than the remaining four. (Author) [pt

  20. LLNL Input to SNL L2 MS: Report on the Basis for Selection of Disposal Options

    International Nuclear Information System (INIS)

    Sutton, M.; Blink, J.A.; Halsey, W.G.

    2011-01-01

    This mid-year deliverable has two parts. The first part is a synopsis of J. Blink's interview of the former Nevada Attorney General, Frankie Sue Del Papa, which was done in preparation for the May 18-19, 2010 Legal and Regulatory Framework Workshop held in Albuquerque. The second part is a series of sections written as input for the SNL L2 Milestone M21UF033701, due March 31, 2011. Disposal of high-level radioactive waste is categorized in this review into several categories. Section II discusses alternatives to geologic disposal: space, ice-sheets, and an engineered mountain or mausoleum. Section III discusses alternative locations for mined geologic disposal: islands, coastlines, mid-continent, and saturated versus unsaturated zone. Section IV discusses geologic disposal alternatives other than emplacement in a mine: well injection, rock melt, sub-seabed, and deep boreholes in igneous or metamorphic basement rock. Finally, Secton V discusses alternative media for mined geologic disposal: basalt, tuff, granite and other igneous/metamorphic rock, alluvium, sandstone, carbonates and chalk, shale and clay, and salt.

  1. 1.60 Ga felsic volcanic blocks in the moraines of the Terre Adelie Craton, Antarctica: comparisons with the Gawler Range Volcanics, South Australia

    International Nuclear Information System (INIS)

    Peucat, J.J.; Capdevila, R.; Pecora, L.; Fanning, C.M.; Testut, L.

    2002-01-01

    Rhyodacite and rhyolite blocks found in numerous moraines on the Terre Adelie Craton in Antarctica are samples of a high-temperature high-K calc-alkaline to alkali-calcic igneous suite emplaced at ca 1.60Ga. They comprise lavas and pyroclastic rocks, including ignimbritic varieties, chemically representative of anorogenic and post-orogenic igneous suites. The eruptive centres are probably close to the coast according to radar satellite images that show the trace of the ice streams. The volcanic suite is similar in age, petrography and chemical composition (major and trace elements as well as Nd isotopes) to the Gawler Range Volcanics from the Gawler Craton of South Australia. These similarities strengthen correlations previously established between the Gawler Craton and the Terre Adelie Craton (Mawson Continent). Moreover, the present petrological, geochemical and geochronological data give a new insight into the last major thermal event affecting the Mawson Continent. The results also highlight the useful contribution of moraines to our knowledge of Antarctic geology. Copyright (2002) Geological Society of Australia

  2. LLNL Input to SNL L2 MS: Report on the Basis for Selection of Disposal Options

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, M; Blink, J A; Halsey, W G

    2011-03-02

    This mid-year deliverable has two parts. The first part is a synopsis of J. Blink's interview of the former Nevada Attorney General, Frankie Sue Del Papa, which was done in preparation for the May 18-19, 2010 Legal and Regulatory Framework Workshop held in Albuquerque. The second part is a series of sections written as input for the SNL L2 Milestone M21UF033701, due March 31, 2011. Disposal of high-level radioactive waste is categorized in this review into several categories. Section II discusses alternatives to geologic disposal: space, ice-sheets, and an engineered mountain or mausoleum. Section III discusses alternative locations for mined geologic disposal: islands, coastlines, mid-continent, and saturated versus unsaturated zone. Section IV discusses geologic disposal alternatives other than emplacement in a mine: well injection, rock melt, sub-seabed, and deep boreholes in igneous or metamorphic basement rock. Finally, Secton V discusses alternative media for mined geologic disposal: basalt, tuff, granite and other igneous/metamorphic rock, alluvium, sandstone, carbonates and chalk, shale and clay, and salt.

  3. Analysis on the inbound tourist source market in Fujian Province

    Science.gov (United States)

    YU, Tong

    2017-06-01

    The paper analyzes the development and structure of inbound tourism in Fujian Province by Excel software and conducts the cluster analysis on the inbound tourism market by SPSS 23.0 software based on the inbound tourism data of Fujian Province from 2006 to 2015. The results show: the rapid development of inbound tourism in Fujian Province and the diversified inbound tourist source countries indicate the stability of inbound tourism market; the inbound tourist source market in Fujian Province can be divided into four categories according to the cluster analysis, and tourists from the United States, Japan, Malaysia, and Singapore are the key of inbound tourism in Fujian Province.

  4. Municipal solid waste management in Kurdistan Province, Iran.

    Science.gov (United States)

    Abduli, Mohammad Ali; Nasrabadi, Touraj

    2007-03-01

    Kurdistan Province, with an area of 28,203 square kilometers, is located in a mountainous area in the western part of Iran. From 1967 to 1997, the urban population in the major eight cities of the Kurdistan Province-namely, Baneh, Bijar, Divan Darreh, Saghez, Sanandaj, Ghorveh, Kamyaran, and Marivan-increased from 102,250 to 705,715. The proportion of the population residing in urban areas increased 90 percent during this period. In most of the cities, solid waste handling remains primitive, and well-organized procedures for it have not been established. Traditional methods of disposal, with marginal inclusion of modern conveniences, appear to be the common practice. In general, the shortcomings of the prevailing practices can be summarized as follows: The municipal solid waste management systems (MSWMSs) in this province include unsegregated collection and open dumping of municipal solid wastes. Separation of municipal solid waste in this province is in the hands of scavengers. The MSWMSs in this province lack essential infrastructure. Thus, design and implementation of modern MSWMSs in this province are essential. Principal criteria for and methods of implementing these systems are as follows: (1) rationally evaluating all functional elements so that they operate in a steady-state or equilibrium manner; (2) creating all support elements for the MSWMS in each city; (3) introducing gradual privatization of MSWMS activities; (4) creating guidelines, regulations, and instructions for all elements of MSWMSs; and (5) giving priorities to source separation and recycling programs. This paper reviews the present status of MSWMSs in eight major cities of Kurdistan Province and outlines the principle guidelines and alternatives for MSWMSs.

  5. Zircon U-Pb geochronology and emplacement history of intrusive rocks in the Ardestan section, central Iran

    Energy Technology Data Exchange (ETDEWEB)

    Sarjoughian, F.; Kananian, A.

    2017-11-01

    The Urumieh-Dokhtar Magmatic Arc (UDMA) is part of the Alpine–Himalayan orogenic belt and interpreted to be a subduction-related Andean-type magmatic arc. Along this belt, Eocene volcanics and some gabbroic to granitic bodies crop out. The main rock types of the studied intrusion are granite, granodiorite, and diorite. They have geochemical features typical of magnesian, calc-alkaline, metaluminous to slightly peraluminous granites and I-type intrusive rock that have a strong enrichment in Large-Ion Lithophile (LIL) elements (e.g. Rb, Ba, Sr), and a depletion in High Field Strength (HFS) elements (e.g. Nb, Ti, P), typical of subduction-related magmas. Zircon U-Pb dating was applied to determine the emplacement ages of the different intrusions in the Ardestan area. Among them the Kuh-e Dom diorite is 53.9±0.4Ma old; the Kuh-e Dom granodiorite is 51.10±0.4Ma old; the Mehrabad granodiorite is 36.8±0.5Ma old, the Nasrand granodiorite is 36.5±0.5Ma old, the Zafarghand granodiorite is 24.6±1.0Ma old, and the Feshark granodiorite is 20.5±0.8Ma old. These results delineate more accurately the magmatic evolution related to the Neotethyan subduction from the Lower Eocene to Lower Miocene, and the subsequent Zagros orogeny that resulted from the Arabia-Eurasia collision. The emplacement of these intrusive rocks inside the UDMA, which has a close relationship with the collisional orogeny, is transitional from a subduction-related setting to post-collisional setting in the Ardestan area.

  6. Zircon U-Pb geochronology and emplacement history of intrusive rocks in the Ardestan section, central Iran

    International Nuclear Information System (INIS)

    Sarjoughian, F.; Kananian, A.

    2017-01-01

    The Urumieh-Dokhtar Magmatic Arc (UDMA) is part of the Alpine–Himalayan orogenic belt and interpreted to be a subduction-related Andean-type magmatic arc. Along this belt, Eocene volcanics and some gabbroic to granitic bodies crop out. The main rock types of the studied intrusion are granite, granodiorite, and diorite. They have geochemical features typical of magnesian, calc-alkaline, metaluminous to slightly peraluminous granites and I-type intrusive rock that have a strong enrichment in Large-Ion Lithophile (LIL) elements (e.g. Rb, Ba, Sr), and a depletion in High Field Strength (HFS) elements (e.g. Nb, Ti, P), typical of subduction-related magmas. Zircon U-Pb dating was applied to determine the emplacement ages of the different intrusions in the Ardestan area. Among them the Kuh-e Dom diorite is 53.9±0.4Ma old; the Kuh-e Dom granodiorite is 51.10±0.4Ma old; the Mehrabad granodiorite is 36.8±0.5Ma old, the Nasrand granodiorite is 36.5±0.5Ma old, the Zafarghand granodiorite is 24.6±1.0Ma old, and the Feshark granodiorite is 20.5±0.8Ma old. These results delineate more accurately the magmatic evolution related to the Neotethyan subduction from the Lower Eocene to Lower Miocene, and the subsequent Zagros orogeny that resulted from the Arabia-Eurasia collision. The emplacement of these intrusive rocks inside the UDMA, which has a close relationship with the collisional orogeny, is transitional from a subduction-related setting to post-collisional setting in the Ardestan area.

  7. Isostatic model for the Tharsis province, Mars

    International Nuclear Information System (INIS)

    Sleep, N.H.; Phillips, R.J.

    1979-01-01

    A crust-upper mantle configuration is proposed for the Tharsis province of Mars which is isostatic and satisfies the observed gravity data. The model is that of a low density upper mantle compensating loads at both the surface and crust-mantle boundary. Solutions are found for lithospheric thickness greater than about 300 km, for which the stress differences are less than 750 bars. This model for Tharsis is similar to the compensation mechanism under the Basin and Range province of the western United States. These provinces also compare favorably in the sense that they are both elevated regions of extensional tectonics and extensive volcanism

  8. Primary vesicles, vesicle-rich segregation structures and recognition of primary and secondary porosities in lava flows from the Paraná igneous province, southern Brazil

    Science.gov (United States)

    Barreto, Carla Joana S.; de Lima, Evandro F.; Goldberg, Karin

    2017-04-01

    This study focuses on a volcanic succession of pāhoehoe to rubbly lavas of the Paraná-Etendeka Province exposed in a single road profile in southernmost Brazil. This work provides an integrated approach for examining primary vesicles and vesicle-rich segregation structures at the mesoscopic scale. In addition, this study provides a quantitative analysis of pore types in thin section. We documented distinct distribution patterns of vesicle and vesicle-rich segregation structures according to lava thickness. In compound pāhoehoe lavas, the cooling allows only vesicles (pipe vesicles to be frozen into place. In inflated pāhoehoe lavas, vesicles of different sizes are common, including pipe vesicles, and also segregation structures such as proto-cylinders, cylinders, cylinder sheets, vesicle sheets, and pods. In rubbly lavas, only vesicles of varying sizes occur. Gas release from melt caused the formation of primary porosity, while hydrothermal alteration and tectonic fracturing are the main processes that generated secondary porosity. Although several forms of porosity were created in the basaltic lava flows, the precipitation of secondary minerals within the pores has tended to reduce the original porosities. Late-stage fractures could create efficient channel networks for possible hydrocarbon/groundwater migration and entrapment owing to their ability to connect single pores. Quantitative permeability data should be gathered in future studies to confirm the potential of these lavas for store hydrocarbons or groundwater.

  9. Basalt-trachybasalt samples in Gale Crater, Mars

    International Nuclear Information System (INIS)

    Edwards, Peter H.; Anderson, Ryan B.; Dyar, Darby

    2017-01-01

    The ChemCam instrument on the Mars Science Laboratory (MSL) rover, Curiosity, observed numerous igneous float rocks and conglomerate clasts, reported previously. A new statistical analysis of single-laser-shot spectra of igneous targets observed by ChemCam shows a strong peak at ~55 wt% SiO 2 and 6 wt% total alkalis, with a minor secondary maximum at 47–51 wt% SiO 2 and lower alkali content. The centers of these distributions, together with the rock textures, indicate that many of the ChemCam igneous targets are trachybasalts, Mg# = 27 but with a secondary concentration of basaltic material, with a focus of compositions around Mg# = 54. We suggest that all of these igneous rocks resulted from low-pressure, olivine-dominated fractionation of Adirondack (MER) class-type basalt compositions. This magmatism has subalkaline, tholeiitic affinities. The similarity of the basalt endmember to much of the Gale sediment compositions in the first 1000 sols of the MSL mission suggests that this type of Fe-rich, relatively low-Mg#, olivine tholeiite is the dominant constituent of the Gale catchment that is the source material for the fine-grained sediments in Gale. The similarity to many Gusev igneous compositions suggests that it is a major constituent of ancient Martian magmas, and distinct from the shergottite parental melts thought to be associated with Tharsis and the Northern Lowlands. Finally, the Gale Crater catchment sampled a mixture of this tholeiitic basalt along with alkaline igneous material, together giving some analogies to terrestrial intraplate magmatic provinces.

  10. Triassic tholeiitic dolerites («ophites» of the El Grado diapir (Pyrenees, Huesca, Spain: emplacement and composition

    Directory of Open Access Journals (Sweden)

    Lago San José, M.

    2000-04-01

    Full Text Available Mesozoic dolerites in the south Pyrenean sector of El Grado (Huesca, Spain preserve emplacement structures (fluidity structures at the top and load structures at the base developed during their intrusion into unconsolidated marly-evaporitic Triassic sediments (Keuper facies. By analogy with other dolerites in the south Pyrenean domain, their emplacement age is equivalent to the uppermost Keuper facies terms, but prior to the final Triassic-early Liassic carbonated sediments. Radiometric ages (187-197±7 Ma show that the emplacement occurred during the lower Liassic. The petralogical differentiation from the chilled margin facies to the central facies, and also to the late pegmatitoids, is consistent with that obtained from major elements, trace elements and REE. Their tholeiitic affinity, as defined by their geochemical composition, is equivalent to that of similar racks in the Pyrenean domain. However, the rocks analyzed here, which are located at the external sector of this domain, display a greater petralogical and geochemical differentiation as compared to similar rocks in the central sectors of the Pyrenean domain.Las doleritas mesozoicas del sector surpirenaico de El Grado (Huesca conservan estructuras de emplazamiento (con desarrollo del movimiento de lava fluida al techo y de carga en su base desarrolladas al instruir en los sedimentos margo-evaporíticos en facies Keuper, todavía inconsolidados. Por similitud con otras doleritas del dominio surpirenaico, la edad del emplazamiento es equivalente a la de los términos superiores de la facies Keuper y previa a la sedimentación carbonatada del Trías terminal-Lías inferior. Las determinaciones de edades radiométricas (187-197±7 Ma indican que el emplazamiento debió tener lugar durante el Lías inferior. La diferenciación petralógica, desde la facies del borde enfriado a la central y, también, al posterior diferenciado pegmatoide concuerda con la obtenida con elementos mayores

  11. Metabauxite horizons containing remobilized-origin gem diaspore and related mineralization, Milas-Muğla province, SW Turkey

    Science.gov (United States)

    Hatipoğlu, Murat; Türk, Necdet; Chamberlain, Steven C.; Murat Akgün, A.

    2010-10-01

    Remobilized-origin gem diaspore and related minerals occur as infill within structurally controlled voids that developed in the upper of two distinct karst unconformity-type metabauxite (diasporite) horizons in the İlbir Mountains area of the Milas-Muğla province, SW Turkey. Colour-change diaspore (trademarked as zultanite) and associated mineral specimens (greenish muscovite, chloritoid, donbassite, specular hematite, ilmenite, goethite, and younger calcite) occur in fracture zones (veins and open structures) that cross-cut the metabauxite horizons. The mineralized fracture zones do not extend into the enclosing marbles, probably because of the ductility contrast between the brittle bauxite and relatively plastic carbonate beds. Thick, white to light gray and dark gray limestone beds were deposited in the İlbir Mountains area during the Cretaceous (146-65 Ma), and contain two stratigraphically distinct karst-fill bauxite horizons. Al-, Fe-, Si- and Ti-rich solutions that infiltrated the karstified limestone probably originated from altered schist and gneiss that surround the basin. The limestone beds (>2000 m thick) were subjected to burial metamorphism, forming marble. Subsequently, the marble block was folded during nappe emplacement toward the SSW as part of late Alpine contractional deformation during the Paleogene (65-23.8 Ma). The upper bauxite horizons within the folded block were cross-cut by fracture zones because of their relatively brittle rheology. At this time, increased pressure and temperature in the bauxite horizons resulted in remobilization of the primary constituents of the bauxite within an aqueous complex, resulting in the crystallization of coarse-grained assemblages in the cross-cutting structures. Ultimately, erosion and mineral exploration revealed the steeply dipping bauxite outcrops and mine workings evident today. This paper focuses on the mine geology of surface outcrops of diasporic bauxite, the upper bauxite horizon within

  12. In Situ Dating Experiments of Igneous Rocks Using the KArLE Instrument: A Case Study for Approximately 380 Ma Basaltic Rocks

    Science.gov (United States)

    Cho, Yuichiro; Cohen, Barbara A.

    2018-01-01

    We report new K-Ar isochron data for two approximately 380 Ma basaltic rocks, using an updated version of the Potassium-Argon Laser Experiment (KArLE). These basalts have K contents comparable to lunar KREEP basalts or igneous lithologies found by Mars rovers, whereas previous proof-of-concept studies focused primarily on more K-rich rocks. We continue to measure these analogue samples to show the advancing capability of in situ K-Ar geochronology. KArLE is applicable to other bodies including the Moon or asteroids.

  13. A feasibility study of the disposal of radioactive waste in deep ocean sediments by drilled emplacement

    International Nuclear Information System (INIS)

    Bury, M.R.C.

    1983-08-01

    This report describes the second phase of a study of the feasibility of disposal and isolation of high level radioactive waste in holes drilled deep into the sediments of the ocean. In this phase, work has concentrated on establishing the state of the art of the various operations and developing the design, in particular the drilling operation, the loading of flasks containing waste canisters from supply vessels onto the platform, the handling of radioactive waste on board, and its emplacement into predrilled holes. In addition, an outline design of the offshore platform has been prepared. (author)

  14. The controlling role of positive structures over the metallogenesis and emplacement of inter layer oxidation sandstone type uranium deposits

    International Nuclear Information System (INIS)

    Gu Kangheng; Chen Zuyi

    2010-01-01

    The positive structures in this paper mean the geological structures related to the occurrence of U-metallogenic zones or U-deposit such as anticlines, uplifts and uplifted fault-blocks. Occurrence features of interlayer oxidation sandstone type deposit at the southern margin of Yili basin and southwestern margin of Turpan-Hami basin, the northeastern margin of Jiudong basin illustrate that the sandstone-hosted uranium deposits, the U-mineralized sections and the uranium occurrences are always selectively emplaced on/in positive structures. The reasons for this lie in the formation mechanism of sandstone-hosted U-deposits. The positive structures raised the elevation of ore-hosting sandstone horizon and make it close to ground surface or exposed at the ground surface, which result in the infiltration of uranium and oxygen bearing groundwater from recharge area into host sandstone horizon, and the interlayer oxidation of host sandstone, as well as the dissolution and the migration of uranium in host sandstone, and the reduction mineralization at the oxidation-reduction interface. Sufficient attention should be paid to the controlling role of positive structures over the metallogenesis and emplacement of sandstone-hosted uranium deposits. They could act as an important criterion for recognizing and prognosticating potential uranium mineralized areas in uranium metallogenic zones or uranium-productive sedimentary basins. (authors)

  15. Bedrock geology and mineral resources of the Knoxville 1° x 2° quadrangle, Tennessee, North Carolina, and South Carolina

    Science.gov (United States)

    Robinson, Gilpin R.; Lesure, Frank G.; Marlowe, J. I.; Foley, Nora K.; Clark, S.H.

    2004-01-01

    The Knoxville 1°x 2° quadrangle spans the Southern Blue Ridge physiographic province at its widest point from eastern Tennessee across western North Carolina to the northwest corner of South Carolina. The quadrangle also contains small parts of the Valley and Ridge province in Tennessee and the Piedmont province in North and South Carolina. Bedrock in the Valley and Ridge consists of unmetamorphosed, folded and thrust-faulted Paleozoic miogeoclinal sedimentary rocks ranging in age from Cambrian to Mississippian. The Blue Ridge is a complex of stacked thrust sheets divided into three parts: (1) a west flank underlain by rocks of the Late Proterozoic and Early Cambrian Chilhowee Group and slightly metamorphosed Late Proterozoic Ocoee Supergroup west of the Greenbrier fault; (2) a central part containing crystalline basement of Middle Proterozoic age (Grenville), Ocoee Supergroup rocks east of the Greenbrier fault, and rocks of the Murphy belt; and (3) an east flank containing the Helen, Tallulah Falls, and Richard Russell thrust sheets and the amphibolitic basement complex. All of the east flank thrust sheets contain polydeformed and metamorphosed sedimentary and igneous rocks of mostly Proterozoic age. The Blue Ridge is separated by the Brevard fault zone from a large area of rocks of the Inner Piedmont to the east, which contains the Six Mile thrust sheet and the ChaugaWalhalla thrust complex. All of these rocks are also polydeformed and metamorphosed sedimentary and igneous rocks. The Inner Piedmont rocks in this area occupy both the Piedmont and part of the Blue Ridge physiographic provinces.

  16. Contrasting magmatic structures between small plutons and batholiths emplaced at shallow crustal level (Sierras de Córdoba, Argentina)

    Science.gov (United States)

    Pinotti, Lucio P.; D'Eramo, Fernando J.; Weinberg, Roberto F.; Demartis, Manuel; Tubía, José María; Coniglio, Jorge E.; Radice, Stefania; Maffini, M. Natalia; Aragón, Eugenio

    2016-11-01

    Processes like injection, magma flow and differentiation and influence of the regional strain field are here described and contrasted to shed light on their role in the formation of small plutons and large batholiths their magmatic structures. The final geometric and compositional arrangement of magma bodies are a complex record of their construction and internal flow history. Magma injection, flow and differentiation, as well as regional stresses, all control the internal nature of magma bodies. Large magma bodies emplaced at shallow crustal levels result from the intrusion of multiple magma batches that interact in a variety of ways, depending on internal and external dynamics, and where the early magmatic, growth-related structures are commonly overprinted by subsequent history. In contrast, small plutons emplaced in the brittle-ductile transition more likely preserve growth-related structures, having a relatively simple cooling history and limited internal magma flow. Outcrop-scale magmatic structures in both cases record a rich set of complementary information that can help elucidate their evolution. Large and small granitic bodies of the Sierra Pampeanas preserve excellent exposures of magmatic structures that formed as magmas stepped through different rheological states during pluton growth and solidification. These structures reveal not only the flow pattern inside magma chambers, but also the rheological evolution of magmas in response to temperature evolution.

  17. Control of Precambrian basement deformation zones on emplacement of the Laramide Boulder batholith and Butte mining district, Montana, United States

    Science.gov (United States)

    Berger, Byron R.; Hildenbrand, Thomas G.; O'Neill, J. Michael

    2011-01-01

    What are the roles of deep Precambrian basement deformation zones in the localization of subsequent shallow-crustal deformation zones and magmas? The Paleoproterozoic Great Falls tectonic zone and its included Boulder batholith (Montana, United States) provide an opportunity to examine the importance of inherited deformation fabrics in batholith emplacement and the localization of magmatic-hydrothermal mineral deposits. Northeast-trending deformation fabrics predominate in the Great Falls tectonic zone, which formed during the suturing of Paleoproterozoic and Archean cratonic masses approximately 1,800 mega-annum (Ma). Subsequent Mesoproterozoic to Neoproterozoic deformation fabrics trend northwest. Following Paleozoic through Early Cretaceous sedimentation, a Late Cretaceous fold-and-thrust belt with associated strike-slip faulting developed across the region, wherein some Proterozoic faults localized thrust faulting, while others were reactivated as strike-slip faults. The 81- to 76-Ma Boulder batholith was emplaced along the reactivated central Paleoproterozoic suture in the Great Falls tectonic zone. Early-stage Boulder batholith plutons were emplaced concurrent with east-directed thrust faulting and localized primarily by northwest-trending strike-slip and related faults. The late-stage Butte Quartz Monzonite pluton was localized in a northeast-trending pull-apart structure that formed behind the active thrust front and is axially symmetric across the underlying northeast-striking Paleoproterozoic fault zone, interpreted as a crustal suture. The modeling of potential-field geophysical data indicates that pull-apart?stage magmas fed into the structure through two funnel-shaped zones beneath the batholith. Renewed magmatic activity in the southern feeder from 66 to 64 Ma led to the formation of two small porphyry-style copper-molybdenum deposits and ensuing world-class polymetallic copper- and silver-bearing veins in the Butte mining district. Vein orientations

  18. Coal comprehensive utilization is the gateway for Shanxi Province

    International Nuclear Information System (INIS)

    Ma, L.; Gui, G.

    1997-01-01

    Shanxi Province is abundant in coal reserve. Taiyuan Coal Gasification Corporation is a large sized union enterprise engaged in comprehensive use of coal in Shanxi province, and significant economic, social, environmental benefits have been brought forth with it. This leads people to believe that coal comprehensive utilization is the gateway for Shanxi Province in the fields of improvement of environment and development of economy

  19. Alteration, age, and emplacement of the Tangihua Complex ophiolite, New Zealand

    International Nuclear Information System (INIS)

    Nicholson, K.N.; Black, P.M.; Picard, C.; Cooper, P.; Hall, C.M.; Itaya, T.

    2007-01-01

    The Tangihua Complex, New Zealand, represents an upper sequence of Late Cretaceous oceanic crustal material: massive basalt flows, pillow lavas, and dolerites. Three phases of alteration are preserved within the complex, each characterised by zeolite precipitation, which correlate to stratigraphic position. The mylonitised sole contains greenschist assemblages (c. 325 degrees C) grading upwards into the initial phase of alteration (250-300 degrees C), and is characterised by actinolite, epidote, albite, and Na-rich zeolites. This phase is cut by lower temperature veins of chlorite-smectite and Ca-rich zeolites. The final alteration phase ( + and Ca 2+ rich minerals, including apophyllite and calcite. Disruption of Ar/Ar spectra around 50 Ma correlate with rifting in the Loyalty Basin and initiation of obduction along the Loyalty-Three Kings Ridge system. We suggest that these events resulted in initial dismemberment, alteration, and movement of the ophiolite, whereas Ar/Ar plateaux at 25-35 Ma correspond to ophiolite emplacement and the last phases of alteration. (author). 49 refs., 5 figs., 3 tabs

  20. DEMAND FOR BEEF IN THE PROVINCE OF YOGYAKARTA

    Directory of Open Access Journals (Sweden)

    Sulistiya

    2014-07-01

    Full Text Available RACT Protein consumption level of society in Yogyakarta Province has yet to meet the target, but the beef is a source of animal protein that is easily obtainable. Therefore, research on the analysis of demand for beef in this province needs to be done. Objective: (1 Determine the factors that affect the demand for beef in Yogyakarta. (2 Determine the own price elasticity and income elasticity of demand for beef in this province, and to know the cross-price elasticity of demand for beef to changes in the price of mutton, chicken, rice, and cooking oil. Metode: descriptive statistics, followed by inductive statistics , and hypothesis testing. The data used are primary and secondary data. Data were analyzed by multiple linear regression with the value of t and F tests, and analysis of the coefficient of determination. Results: Taken together, the factors that affect the demand for beef in the province is the price of beef, mutton, chicken, rice, cooking oil, income, number of inhabitants. Individually, beef demand is influenced by the price of beef and income residents. Beef inelastic demand means that beef is the daily necessities that are affordable and easy to obtain population of Yogyakarta Province. The increase in income population does not add to demand for beef. Substitutes of beef in the province is goat and chicken, while the complementary goods are rice and cooking oil.

  1. Emplacement feasibility of a multi-tier, expanded capacity repository at Yucca Mountain, Nevada USA

    International Nuclear Information System (INIS)

    Apted, Michael; Kessler, John; Fairhurst, Charles

    2008-01-01

    A geological repository at Yucca Mountain has been proposed for the disposal of spent fuel from the US commercial reactors and other radioactive waste. A legislative capacity of 70,000 MTHM has been set by the Nuclear Waste Policy Act of 1982, including 63,000 MTHM of commercial spent nuclear fuel (CSNF), the projected amount of CSNF that will be produced by about 2014. Policy issues remain as to how to handle waste that is generated beyond 2014 from a growing nuclear industry in the US. The Electric Power Research Institute (EPRI) is independently evaluating the technical, rather than legislative, limit of CSNF that could be safely disposed at Yucca Mountain. Geological, thermal management, safety and cost factors have been recently evaluated by EPRI (2006; 2007) for grouped emplacement drifts and/or a multi-tier repository. EPRI's evaluation of emplacement feasibility for a multi-tier concept is described here. Expanded capacity concepts as envisioned for Yucca Mountain (EPRI, 2006; 2007) assume excavation of one or two additional levels of drifts parallel to or above and/or below the original drift excavations. For the latter multi-tier concept each 'tier' or 'level' would essentially replicate the original layer with a 30-m separation between tiers. This arrangement essentially doubles or triples the capacity of the repository for a two- or three-tier design, respectively. The main issues that affect the feasibility of expanded capacity design are; (i) ventilation requirements; (ii) radiation hazards; (iii) thermal and thermo-mechanical constraints. (i)Ventilation: The repository design involves waste packages mounted in close proximity to each other in 600-m long drifts that remain open and actively ventilated for at least 50-100 years. Analyses,conservatively assuming that all three repository levels operate simultaneously, indicate no technological obstacles in meeting ventilation requirements for sustained simultaneous operation ba sed on current industrial

  2. High radioactive heat-producing, economically potential granites around Jodhpur city, Malani Igneous Suite, Northwestern India

    International Nuclear Information System (INIS)

    Shrivastava, K.L.; Prajapat, Tina; Mathur, Anju; Gaur, Virendra; Dadhich; Mamta Chauhan, C.P.; Tripathi, Beena

    2013-01-01

    In the south and southeast periphery of the desert city of Jodhpur, there are pink and grey granite islands in the desert sand at Fitkasni-Rasida and Salawas-Nandanvan areas of Malani Igneous Suite (Neoproterozoic). We are reporting the average heat generation value of 15.33 HGU for first and 8.83 HGU for the second area that is much higher than the average (3.8 HGU) known for the continental crust. The concentration of uranium determined is two to four times higher than the average continental crust and thorium is still higher than U and K. The radioelement concentration (Ur) varies from 25.06 to 27 in the Salawas-Nandanvan granites and 43.73 to 75.81 in Fitkasni-Rasida granites. It clearly indicates a 'hot crust', hence favourable for the formation of mineralization of HFS elements, Nb, Ce, REE, U and Th, which need yet to be explored. (author)

  3. Proterozoic kimberlites and lamproites and a preliminary age for the Argyle lamproite pipe, Western Australia

    International Nuclear Information System (INIS)

    Skinner, E.M.W.; Bristow, J.W.; Smith, C.B.; Scott Smith, B.H.; Dawson, J.B.

    1985-01-01

    The Argyle pipe occurring in the East Kimberley Province of Western Australia is a unique, highly-diamondiferous lamproite. Although it resembles other lamproites located in the West Kimberley Province with respect to its setting, structure, petrography and geochemistry, it is probably Proterozoic in age and hence substantially older than Tertiary occurrences of the West Kimberley Province. Rb-Sr measurements on whole rock and phlogopite samples from magmatic olivine-phlogopite lamproite, reveals a two point model age of 1126 +- 9 Ma for the Argyle pipe. This age is consistent with ages of other, similar volcanic igneous rocks occurring in several localities worldwide. The widespread occurrence of Proterozoic kimberlites and lamproites suggests that this was an important period of worldwide alkalic intrusive activity

  4. Analysis of thermal-hydrologic-mechanical behavior near an emplacement drift at Yucca Mountain

    International Nuclear Information System (INIS)

    Rutqvist, Jonny; Tsang, Chin-Fu

    2002-01-01

    A coupled thermal, hydrologic and mechanical (THM) analysis is conducted to evaluate the impact of coupled THM processes on the performance of a potential nuclear waste repository at Yucca Mountain, Nevada. The analysis considers changes in rock mass porosity, permeability, and capillary pressure caused by rock deformations during drift excavation, as well as those caused by thermo-mechanically induced rock deformations after emplacement of the heat-generating waste. The analysis consists of a detailed calibration of coupled hydraulic-mechanical rock mass properties against field experiments, followed by a prediction of the coupled thermal, hydrologic, and mechanical behavior around a potential repository drift. For the particular problem studied and parameters used, the analysis indicates that the stress-induced permeability changes will be within one order of magnitude and that these permeability changes do not significantly impact the overall flow pattern around the repository drift

  5. Design of the human computer interface on the telerobotic small emplacement excavator

    International Nuclear Information System (INIS)

    Thompson, D.H.; Killough, S.M.; Burks, B.L.; Draper, J.V.

    1995-01-01

    The small emplacement excavator (SEE) is a ruggedized military vehicle with backhoe and front loader used by the U.S. Army for explosive ordinance disposal (EOD) and general utility excavation activities. This project resulted from a joint need in the U.S. Department of Energy (DOE) for a remote controlled excavator for buried waste operations and the U.S. Department of Defense for remote EOD operations. To evaluate the feasibility of removing personnel from the SEE vehicle during high-risk excavation tasks, a development and demonstration project was initiated. Development of a telerobotic SEE (TSEE) was performed by the Oak Ridge National Laboratory in a project funded jointly by the U.S. Army and the DOE. The TSEE features teleoperated driving, a telerobotic backhoe with four degrees of freedom, and a teleoperated front loader with two degrees of freedom on the bucket. Remote capabilities include driving (forward, reverse, brake, steering), power takeoff shifting to enable digging modes, deploying stabilizers, excavation, and computer system booting

  6. Pre-Alleghenian (Pennsylvanian-Permian) hydrocarbon emplacement along Ordovician Knox unconformity, eastern Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    Haynes, F.M.; Kesler, S.E.

    1989-03-01

    Cores taken during exploration for Mississippi Valley-type lead and zinc ores in the Mascot-Jefferson City zinc district of eastern Tennessee commonly contain hydrocarbon residues in carbonate rocks of the Knox Group immediately below the Lower Ordovician Knox unconformity. The location and number of these residue-bearing strata reveal information about the Paleozoic history of hydrocarbon emplacement in the region. Contour maps, generated from nearly 800 holes covering more than 20 km/sup 2/, indicate that zones with elevated organic content in the uppermost 30 m of the Lower Ordovician Mascot Dolomite show a strong spatial correlation with Middle Ordovician paleotopographic highs. These same zones show no spatial association with present-day structural highs, which were formed during Pennsylvanian-Permian Alleghenian tectonism. This suggests that the physical entrapment of hydrocarbons migrating through the upper permeable units of the Mascot must have occurred prior to the principal tectonism of the Alleghenian orogeny. 7 figures, 1 table.

  7. Emplacement of Xenolith Nodules in the Kaupulehu Lava Flow, Hualalai Volcano, Hawaii

    Science.gov (United States)

    Guest, J. E.; Spudis, P. D.; Greeley, R.; Taylor, G. J.; Baloga, S. M.

    1995-01-01

    The basaltic Kaupulehu 1800-1801 lava flow of Hualalai Volcano, Hawaii contains abundant ultramafic xenoliths. Many of these xenoliths occur as bedded layers of semi-rounded nodules, each thinly coated with a veneer (typically 1 mm thick) of lava. The nodule beds are analogous to cobble deposits of fluvial sedimentary systems. Although several mechanisms have been proposed for the formation of the nodule beds, it was found that, at more than one locality, the nodule beds are overbank levee deposits. The geological occurrence of the nodules, certain diagnostic aspects of the flow morphology and consideration of the inferred emplacement process indicate that the Kaupulehu flow had an exceptionally low viscosity on eruption and that the flow of the lava stream was extremely rapid, with flow velocities of at least 10 m/s (more than 40 km/h. This flow is the youngest on Hualalai Volcano and future eruptions of a similar type would pose considerable hazard to life as well as property.

  8. Homeless Blogs as Travelogues. Travel as a Struggle for Recognition and Emplacement

    Directory of Open Access Journals (Sweden)

    Halina Gąsiorowska

    2017-07-01

    Full Text Available Applying Clifford’s broad concept of travel, I discuss American homeless blogs as autobiographical travel writing serving the struggle for recognition of the street people. The analysed travelogues are hitchhiker Ruth Rader’s Ruthie in the Sky blog and self-made woman Brianna Karp’s Girl’s Guide to Homelessness – a memoir published on the basis of the blog bearing the same title. In the travelogues I analyse the characteristic features of a personal travel writing: travel of the self, advice for future travelers, geographic information and portrayal of society in which the travel is undertaken. I claim that homeless bloggers recounting their stories of otherness and displacement in the US contribute to (reconstructing American cultural identity their personal Self, just like many other American travelers before. Additionally, homeless blogging about homelessness is shown as the process of emplacement (Casey – the bloggers’ attempt of making themselves at home in the world.

  9. Regression-Correlation of Petrophysical Inter-Parameter of Igneous Rocks and Limestone from Kulonprogo Mountain Region, Yogyakarta Special Region

    Directory of Open Access Journals (Sweden)

    Sigit Maryanto

    2014-06-01

    Full Text Available DOI: 10.17014/ijog.v6i4.127Laboratory test of complete petrophysic parameters encompasing water absorption, compressive strength, Los Angeles abrasive strength, Rudellof abrasive strength, and wear resistance with Na2SO4 has been carried out for igneous and carbonate rocks taken from Kulonprogo Mountains region. Statistical verification of the data exhibits variation of correlation coefficients among parameters ranging from medium to very high value. The values of petrophysic test results are determined by the rock types. The result of this study is useful to estimate the accuracy of values of each parameter test result in Geological Survey Institute Laboratory using regression formula representing each relationship.

  10. Late Cretaceous porphyry copper mineralization in Sonora, Mexico: Implications for the evolution of the Southwest North America porphyry copper province

    Science.gov (United States)

    Barra, Fernando; Valencia, Victor A.

    2014-10-01

    Two porphyry Cu-Mo prospects in northern Sonora, Mexico (Fortuna del Cobre and Los Humos) located within the southwestern North American porphyry province have been dated in order to constrain the timing of crystallization and mineralization of these ore deposits. In Fortuna del Cobre, the pre-mineralization granodiorite porphyry yielded an U-Pb zircon age of 76.5 ± 2.3 Ma, whereas two samples from the ore-bearing quartz feldespathic porphyry were dated at 74.6 ± 1.3 and 75.0 ± 1.4 Ma. Four molybdenite samples from Los Humos porphyry Cu prospect yielded a weighted average Re-Os age of 73.5 ± 0.2 Ma, whereas two samples from the ore-bearing quartz monzonite porphyry gave U-Pb zircon ages of 74.4 ± 1.1 and 74.5 ± 1.3 Ma, showing a Late Cretaceous age for the emplacement of this ore deposit. The results indicate that Laramide porphyry Cu mineralization of Late Cretaceous age is not restricted to northern Arizona as previously thought and provide evidence for the definition of NS trending metallogenic belts that are parallel to the paleo-trench. Porphyry copper mineralization follows the inland migration trend of the magmatic arc as a result of the Farallon slab flattening during the Laramide orogeny.

  11. Calculation of drift seepage for alternative emplacement designs

    International Nuclear Information System (INIS)

    Li, Guomin; Tsang, Chin-Fu; Birkholzer, Jens

    1999-01-01

    The calculations presented in this report are performed to obtain seepage rates into drift and boreholes for two alternative designs of drift and waste emplacement at Yucca Mountain. The two designs are defined according to the Scope of Work 14012021M1, activity 399621, drafted October 6, 1998, and further refined in a conference telephone call on October 13, 1998, between Mark Balady, Jim Blink, Rob Howard and Chin-Fu Tsang. The 2 designs considered are: (1) Design A--Horizontal boreholes 1.0 m in diameter on both sides of the drift, with each borehole 8 m long and inclined to the drift axis by 30 degrees. The pillar between boreholes, measured parallel to the drift axis, is 3.3 m. In the current calculations, a simplified model of an isolated horizontal borehole 8 m long will be simulated. The horizontal borehole will be located in a heterogeneous fracture continuum representing the repository layer. Three different realizations will be taken from the heterogeneous field, representing three different locations in the rock. Seepage for each realization is calculated as a function of the percolation flux. Design B--Vertical boreholes, 1.0 m in diameter and 8.0 m deep, drilled from the bottom of an excavated 8.0 m diameter drift. Again, the drift with the vertical borehole will be assumed to be located in a heterogeneous fracture continuum, representing the rock at the repository horizon. Two realizations are considered, and seepage is calculated for the 8-m drift with and without the vertical 1-m borehole at its bottom

  12. Emplacement controls for the basaltic-andesitic radial dikes of Summer Coon volcano and implications for flank vents at stratovolcanoes

    Science.gov (United States)

    Harp, A. G.; Valentine, G. A.

    2018-02-01

    Mafic flank eruptions are common events that pose a serious hazard to the communities and infrastructure often encroaching on the slopes of stratovolcanoes. Flank vent locations are dictated by the propagation path of their feeder dikes. The dikes are commonly thought to propagate either laterally from the central conduit or vertically from a deeper source. However, these interpretations are often based on indirect measurements, such as surface deformation and seismicity at active systems, and several studies at eroded volcanoes indicate the propagation paths may be more complex. We investigated the Oligocene age Summer Coon volcano (Colorado, USA), where erosion has exposed over 700 basaltic-andesitic radial dikes, to constrain the propagation directions, geometries, and spatial distributions of mafic dikes within a stratovolcano. The mean fabric angle of aligned plagioclase crystals was measured in oriented samples from the margins of 77 dikes. Of the 41 dikes with statistically significant flow fabrics, 85% had fabric angles that were inclined—plunging both inward and outward relative to the center of the volcano. After comparing fabric angles to those reported in other studies, we infer that, while most of the dikes with outward-plunging fabrics descended toward the flanks from a source within the edifice and near its axis, dikes with inward-plunging fabrics ascended through the edifice and toward the flanks from a deeper source. A possible control for the inclination of ascending dikes was the ratio between magma overpressure and the normal stress in the host rock. While higher ratios led to high-angle propagation, lower ratios resulted in inclined emplacement. Dikes crop out in higher frequencies within a zone surrounding the volcano axis at 2500 m radial distance from the center and may be the result of ascending dikes, emplaced at similar propagation angles, intersecting the current level of exposure at common distances from the volcano axis. The process

  13. Timing of multiple hydrothermal events in the iron oxide-copper-gold deposits of the Southern Copper Belt, Carajás Province, Brazil

    Science.gov (United States)

    Moreto, Carolina P. N.; Monteiro, Lena V. S.; Xavier, Roberto P.; Creaser, Robert A.; DuFrane, S. Andrew; Melo, Gustavo H. C.; Delinardo da Silva, Marco A.; Tassinari, Colombo C. G.; Sato, Kei

    2015-06-01

    The Southern Copper Belt, Carajás Province, Brazil, hosts several iron oxide-copper-gold (IOCG) deposits, including Sossego, Cristalino, Alvo 118, Bacuri, Bacaba, Castanha, and Visconde. Mapping and U-Pb sensitive high-resolution ion microprobe (SHRIMP) IIe zircon geochronology allowed the characterization of the host rocks, situated within regional WNW-ESE shear zones. They encompass Mesoarchean (3.08-2.85 Ga) TTG orthogneiss, granites, and remains of greenstone belts, Neoarchean (ca. 2.74 Ga) granite, shallow-emplaced porphyries, and granophyric granite coeval with gabbro, and Paleoproterozoic (1.88 Ga) porphyry dykes. Extensive hydrothermal zones include albite-scapolite, biotite-scapolite-tourmaline-magnetite alteration, and proximal potassium feldspar, chlorite-epidote and chalcopyrite formation. U-Pb laser ablation multicollector inductively coupled mass spectrometry (LA-MC-ICP-MS) analysis of ore-related monazite and Re-Os NTIMS analysis of molybdenite suggest multiple Neoarchean (2.76 and 2.72-2.68 Ga) and Paleoproterozoic (2.06 Ga) hydrothermal events at the Bacaba and Bacuri deposits. These results, combined with available geochronological data from the literature, indicate recurrence of hydrothermal systems in the Southern Copper Belt, including 1.90-1.88-Ga ore formation in the Sossego-Curral ore bodies and the Alvo 118 deposit. Although early hydrothermal evolution at 2.76 Ga points to fluid migration coeval with the Carajás Basin formation, the main episode of IOCG genesis (2.72-2.68 Ga) is related to basin inversion coupled with Neoarchean (ca. 2.7 Ga) felsic magmatism. The data suggest that the IOCG deposits in the Southern Copper Belt and those in the Northern Copper Belt (2.57-Ga Salobo and Igarapé Bahia-Alemão deposits) do not share a common metallogenic evolution. Therefore, the association of all IOCG deposits of the Carajás Province with a single extensive hydrothermal system is precluded.

  14. Linking Volcanism and Gas Release from the North East Atlantic Volcanic Province to the PETM: Challenges and Updates

    Science.gov (United States)

    Svensen, H.; Jones, M. T.; Jerram, D. A.; Planke, S.; Kjoberg, S.; Schmid, D. W.; Iyer, K.; Tegner, C.

    2016-12-01

    The main phase of the development of the North East Atlantic Volcanic Province took place about 56 Ma and coincides with the Paleocene Eocene Thermal Maximum (PETM). The volcanic activity was characterized by voluminous flood basalts, large plutonic complexes, sub-marine eruptions, widespread tephra deposition, and emplacement of sills and dikes along the continental margins of Norway, Greenland, Ireland, and the UK. Here we review the style and tempo of volcanism during this important period of Earth's history and discuss the sources and volumes of the carbon gases emitted to the ocean and atmosphere. Moreover, we present new data and models from 1) West Greenland showing the impact on sill intrusions on gas generation from heated Cretaceous mudstones, 2) a 3D seismic survey of gas release structures offshore Norway, and 3) Paleocene-Eocene tephra layers from Svalbard and Denmark. Gas migrated out of the contact aureoles by either explosive venting or by slower seepage towards the seafloor as demonstrated by 3D seismic data. Some of the gas was permanently trapped (dry gas and CO2-rich gas) in the source rocks and aureoles. Combined with high-precision zircon ages and a time model for the PETM, our approach may give robust fluxes that can explain both the onset and the body of the PETM.

  15. First description of Trypanosoma cruzi human infection in Esmeraldas province, Ecuador.

    Science.gov (United States)

    Guevara, Ángel; Moreira, Juan; Criollo, Hipatia; Vivero, Sandra; Racines, Marcia; Cevallos, Varsovia; Prandi, Rosanna; Caicedo, Cynthia; Robinzon, Francisco; Anselmi, Mariella

    2014-08-06

    Chagas disease was described in Ecuador in 1930 in the province of Guayas and thereafter in various provinces. Triatomine were reported in the province of Esmeraldas but no human infection has been described. Here we report the first evidence that the disease does exist in the province of Esmeraldas. In indigenous Awá communities located in the northwest jungle of the Esmeraldas province, 144 individuals were tested using ELISA and PCR for T.cruzi of which 5 (3.47%) were positive. Twenty eight triatomine were collected, 27 were Triatoma dispar and 1 Pastrongylus rufotuberculatus, T.cruzi was detected in 11 (42.3%) of 26 insects.

  16. Challenges for emerging livestock farmers in Limpopo province ...

    African Journals Online (AJOL)

    Challenges for emerging livestock farmers in Limpopo province, South Africa. ND MacLeod, CK McDonald, FP van Oudtshoorn. Abstract. Land redistribution schemes (e.g. Settlement Land Acquisition Grant and Land Redistribution for Agricultural Development) initiated since the mid-1990s in Limpopo province under ...

  17. Technical operations procedure for assembly and emplacement of the soil temperature test--test assembly

    International Nuclear Information System (INIS)

    Weber, A.P.

    1978-01-01

    A description is given of the plan for assembly, instrumentation, emplacement, and operational checkout of the soil temperature test assembly and dry well liner. The activities described cover all operations necessary to accomplish the receiving inspection, instrumentation and pre-construction handling of the dry well liner, plus all operations performed with the test article. Actual details of construction work are not covered by this procedure. Each part and/or section of this procedure is a separate function to be accomplished as required by the nature of the operation. The organization of the procedure is not intended to imply a special operational sequence or schedular requirement. Specific procedure operational sections include: receiving inspection; liner assembly operations; construction operations (by others); prepare shield plug; test article assembly and installation; and operational checkout

  18. Recurrent uranium relocations in distal turbidites emplaced in pelagic conditions

    International Nuclear Information System (INIS)

    Colley, S.; Thomson, J.

    1985-01-01

    The sediments of the Madeira Abyssal Plain, east of Great Meteor Seamount, are dominated by distal turbidite deposition. While the turbidites exhibit a wide compositional range, individual examples can be correlated over a wide area and are relatively homogeneous. Organic C oxidation, by bottom water oxygen, proceeds from the turbidite tops downwards after emplacement in pelagic conditions, and the progress of this oxidation front is marked by a sharp colour contrast in the sediments. In turbidites with Csub(org) > 0.5%, redistribution of authigenic U occurs to form a concentration peak (4 to 9 ppm U), just below the oxidation front or colour change. Several tens μg U/cm 2 may be mobilised, and in all examples studied > 60% of the remobilised U is relocated into the peak. Following burial by subsequent turbidites, such U concentration peaks are persistent as relict indicators of their extinct oxidation fronts for at least 2 x 10 5 years. In the case of thin turbidites where labile Csub(org) is almost exhausted, the U peaks may be located in underlying sedimentary units because of their relationship to the oxidation front. A redox mechanism for U peak formation is suggested from these data rather than a complexation with organic matter. (author)

  19. Ted Irving and the Precambrian continental drift of (within?) the Canadian Shield

    Science.gov (United States)

    Hoffman, P. F.

    2014-12-01

    Ted Irving was no stranger to the Precambrian when he began paleomagnetic studies in the Canadian Shield (CS) that would dominate his research in the early and mid-1970's. Twenty years before, his graduate work on billion-year-old strata in Scotland established paleomagnetic methodologies applicable to sedimentary rocks generally. In 1958, he and Ronald Green presented an 'Upper Proterozoic' APW path from Australia as evidence for pre-Carboniferous drift relative to Europe and North America (the poles actually range in age from 1.2 to 2.7 Ga). His first published CS poles were obtained from the Franklin LIP of the Arctic platform and demonstrate igneous emplacement across the paleoequator. Characteristically, his 1971 poles are statistically indistinguishable from the most recent grand mean paleopole of 2009. His main focus, however, was on the question of Precambrian continental drift. He compared APW paths with respect to Laurentia with those obtained from other Precambrian shields, and he compared APW paths from different tectonic provinces within the CS. He was consistently antagonistic to the concept of a single long-lived Proterozoic supercontinent, but he was on less certain ground regarding motions within the CS due to inadequate geochronology. With Ron Emslie, he boldly proposed rapid convergence between parts of the Grenville Province and Interior Laurentia (IL) ~1.0 Ga. This was controversial given the uncertain ages of multiple magnetic components in high-grade metamorphic rocks. With John McGlynn and John Park, he developed a Paleoproterozoic APW path for the Slave Province from mafic dikes and red clastics, encompassing the time of consolidation of IL during 2.0-1.8 Ga orogenesis. Before 1980, he constructed Paleoproterozoic APW paths for IL as a whole, finding little evidence for significant internal displacement. He recognized that the Laurentian APW path describes a series of straight tracks linked by hairpins, the latter corresponding in age to

  20. Characterize Framework for Igneous Activity at Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    F. Perry; R. Youngs

    2004-10-14

    The purpose of this scientific analysis report is threefold: (1) Present a conceptual framework of igneous activity in the Yucca Mountain region (YMR) consistent with the volcanic and tectonic history of this region and the assessment of this history by experts who participated in the probabilistic volcanic hazard analysis (PVHA) (CRWMS M&O 1996 [DIRS 100116]). Conceptual models presented in the PVHA are summarized and applied in areas in which new information has been presented. Alternative conceptual models are discussed, as well as their impact on probability models. The relationship between volcanic source zones defined in the PVHA and structural features of the YMR are described based on discussions in the PVHA and studies presented since the PVHA. (2) Present revised probability calculations based on PVHA outputs for a repository footprint proposed in 2003 (BSC 2003 [DIRS 162289]), rather than the footprint used at the time of the PVHA. This analysis report also calculates the probability of an eruptive center(s) forming within the repository footprint using information developed in the PVHA. Probability distributions are presented for the length and orientation of volcanic dikes located within the repository footprint and for the number of eruptive centers (conditional on a dike intersecting the repository) located within the repository footprint. (3) Document sensitivity studies that analyze how the presence of potentially buried basaltic volcanoes may affect the computed frequency of intersection of the repository footprint by a basaltic dike. These sensitivity studies are prompted by aeromagnetic data collected in 1999, indicating the possible presence of previously unrecognized buried volcanoes in the YMR (Blakely et al. 2000 [DIRS 151881]; O'Leary et al. 2002 [DIRS 158468]). The results of the sensitivity studies are for informational purposes only and are not to be used for purposes of assessing repository performance.