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Sample records for east formation petrology

  1. Coal geology of the Paleocene-Eocene Calvert Bluff Formation (Wilcox Group) and the Eocene Manning Formation (Jackson Group) in east-central Texas; field trip guidebook for the Society for Organic Petrology, Twelfth Annual Meeting, The Woodlands, Texas, August 30, 1995

    Science.gov (United States)

    Warwick, Peter D.; Crowley, Sharon S.

    1995-01-01

    The Jackson and Wilcox Groups of eastern Texas (fig. 1) are the major lignite producing intervals in the Gulf Region. Within these groups, the major lignite-producing formations are the Paleocene-Eocene Calvert Bluff Formation (Wilcox) and the Eocene Manning Formation (Jackson). According to the Keystone Coal Industry Manual (Maclean Hunter Publishing Company, 1994), the Gulf Coast basin produces about 57 million short tons of lignite annually. The state of Texas ranks number 6 in coal production in the United States. Most of the lignite is used for electric power generation in mine-mouth power plant facilities. In recent years, particular interest has been given to lignite quality and the distribution and concentration of about a dozen trace elements that have been identified as potential hazardous air pollutants (HAPs) by the 1990 Clean Air Act Amendments. As pointed out by Oman and Finkelman (1994), Gulf Coast lignite deposits have elevated concentrations of many of the HAPs elements (Be, Cd, Co, Cr, Hg, Mn, Se, U) on a as-received gm/mmBtu basis when compared to other United States coal deposits used for fuel in thermo-electric power plants. Although regulations have not yet been established for acceptable emissions of the HAPs elements during coal burning, considerable research effort has been given to the characterization of these elements in coal feed stocks. The general purpose of the present field trip and of the accompanying collection of papers is to investigate how various aspects of east Texas lignite geology might collectively influence the quality of the lignite fuel. We hope that this collection of papers will help future researchers understand the complex, multifaceted interrelations of coal geology, petrology, palynology and coal quality, and that this introduction to the geology of the lignite deposits of east Texas might serve as a stimulus for new ideas to be applied to other coal basins in the U.S. and abroad.

  2. Formation of cratonic lithosphere: An integrated thermal and petrological model

    Science.gov (United States)

    Herzberg, Claude; Rudnick, Roberta

    2012-09-01

    The formation of cratonic mantle peridotite of Archean age is examined within the time frame of Earth's thermal history, and how it was expressed by temporal variations in magma and residue petrology. Peridotite residues that occupy the lithospheric mantle are rare owing to the effects of melt-rock reaction, metasomatism, and refertilization. Where they are identified, they are very similar to the predicted harzburgite residues of primary magmas of the dominant basalts in greenstone belts, which formed in a non-arc setting (referred to here as "non-arc basalts"). The compositions of these basalts indicate high temperatures of formation that are well-described by the thermal history model of Korenaga. In this model, peridotite residues of extensive ambient mantle melting had the highest Mg-numbers, lowest FeO contents, and lowest densities at ~ 2.5-3.5 Ga. These results are in good agreement with Re-Os ages of kimberlite-hosted cratonic mantle xenoliths and enclosed sulfides, and provide support for the hypothesis of Jordan that low densities of cratonic mantle are a measure of their high preservation potential. Cratonization of the Earth reached its zenith at ~ 2.5-3.5 Ga when ambient mantle was hot and extensive melting produced oceanic crust 30-45 km thick. However, there is a mass imbalance exhibited by the craton-wide distribution of harzburgite residues and the paucity of their complementary magmas that had compositions like the non-arc basalts. We suggest that the problem of the missing basaltic oceanic crust can be resolved by its hydration, cooling and partial transformation to eclogite, which caused foundering of the entire lithosphere. Some of the oceanic crust partially melted during foundering to produce continental crust composed of tonalite-trondhjemite-granodiorite (TTG). The remaining lithosphere gravitationally separated into 1) residual eclogite that continued its descent, and 2) buoyant harzburgite diapirs that rose to underplate cratonic nuclei

  3. MESOZOIC MAGMATISM IN EAST URUGUAY: PETROLOGICAL CONSTRAINTS RELATED TO THE SIERRA SAN MIGUEL REGION

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    Conti Bruno

    2009-07-01

    Full Text Available This work presents new results of a detailed geological and structural investigation focusing the easternmost Uruguayan Mesozoic magmatic occurrences related to the south Atlantic opening. Lithological descriptions, their stratigraphic relationships and complimentary lithochemical characterizations carried out in the San Miguel region (East Uruguay are presented. Three volcanic/sub-volcanic units have been recognized. The felsic volcanic association is composed by rhyolitic - dacitic flows, mainly with porphyritic textures and sub-alkalinenature and related pyroclastic rocks. The felsic sub-volcanic association is characterized by granophyres of about 25 km2 of exposed area, cross- cut by mafic and felsic dykes. Finally, a mafic association has been identified characterized by dykes and a small intrusion of gabbroic composition.All these units are Mesozoic in age (130 - 127 Ma and according to their chemical nature they correspond tosub-alkaline to weak peralkaline magmas.

  4. Petrography and petrology of the Ayghalesi granite, east of Takab area (northwest of Iran

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    Saeed Kamran

    2017-03-01

    Full Text Available The investigated granite intrusion is located at the north of Ayghalesi village, east of Takab The Ayghalesi granite has been intruded the Eocene sandstone and conglomerate rocks and low grade metamorphic hornfels have been metamorphosed host rocks. The main constituent minerals are K-feldspar, plagioclase, quartz and muscovite.and minor garnet. The main texture is granular but pegmatitic, myrmektitic, graphic and perthitic occur as minor textures. Chemically, the rocks are granite on the various classification diagrams. The Ayghalesi intrusion body is classified as S-type, peraluminous composition, calc-alkaline nature and is calcic-alkali to alkali-calcic on the base of modified alkali lime index (MALI. The investigated body, on the tectonic discrimination diagrams, fall on syn-collisional tectonic setting domain, suggesting that it was originated during collision of Central Iranian and Arabian plates Key words: granite,

  5. Petrology and geochemistry of REE-rich Mafé banded iron formations (Bafia group, Cameroon)

    Science.gov (United States)

    Nkoumbou, Charles; Gentry, Fuh Calistus; Tchakounte Numbem, Jacqueline; Belle Ekwe Lobé, Yolande Vanessa; Nwagoum Keyamfé, Christin Steve

    2017-07-01

    Archaean-Paleoproterozoic foliated amphibole-gneisses and migmatites interstratified with amphibolites, pyroxeno-amphibolites and REE-rich banded-iron formations outcrop at Mafé, Ndikinimeki area. The foliation is nearly vertical due to tight folds. Flat-lying quartz-rich mica schists and quartzites, likely of Pan-African age, partly cover the formations. Among the Mafé BIFs, the oxide BIF facies shows white layers of quartz and black layers of magnetite and accessory hematite, whereas the silicate BIF facies is made up of thin discontinuous quartz layers alternating with larger garnet (almandine-spessartine) + chamosite + ilmenite ± Fe-talc layers. REE-rich oxide BIFs compositions are close to the East Pacific Rise (EPR) hydrothermal deposit; silicate BIFs plot midway between EPR and the associated amphibolite, accounting for a contamination by volcanic materials, in addition to the hydrothermal influence during their oceanic deposition. The association of an oceanic setting with alkaline and tholeiitic magmatism is typical of the Algoma-type BIF deposit. The REE-rich BIFs indices recorded at Mafé are interpreted as resulting from an Archaean-Paleoproterozoic mineralization.

  6. PETROLOGIC CONSTRAINTS ON AMORPHOUS AND CRYSTALLINE MAGNESIUM SILICATES: DUST FORMATION AND EVOLUTION IN SELECTED HERBIG Ae/Be SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Rietmeijer, Frans J. M. [Department of Earth and Planetary Sciences, MSC 03 2040, 1-University of New Mexico, Albuquerque, NM 87131-001 (United States); Nuth, Joseph A., E-mail: fransjmr@unm.edu [Astrochemistry Laboratory, Solar System Exploration Division, Code 691, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2013-07-01

    The Infrared Space Observatory, Spitzer Space Telescope, and Herschel Space Observatory surveys provided a wealth of data on the Mg-silicate minerals (forsterite, enstatite), silica, and ''amorphous silicates with olivine and pyroxene stoichiometry'' around Herbig Ae/Be stars. These incredible findings do not resonate with the mainstream Earth Sciences because of (1) disconnecting ''astronomical nomenclature'' and the long existing mineralogical and petrologic terminology of minerals and amorphous materials, and (2) the fact that Earth scientists (formerly geologists) are bound by the ''Principle of Actualism'' that was put forward by James Hutton (1726-1797). This principle takes a process-oriented approach to understanding mineral and rock formation and evolution. This paper will (1) review and summarize the results of laboratory-based vapor phase condensation and thermal annealing experiments, (2) present the pathways of magnesiosilica condensates to Mg-silicate mineral (forsterite, enstatite) formation and processing, and (3) present mineralogical and petrologic implications of the properties and compositions of the infrared-observed crystalline and amorphous dust for the state of circumstellar disk evolution. That is, the IR-observation of smectite layer silicates in HD142527 suggests the break-up of asteroid-like parent bodies that had experienced aqueous alteration. We discuss the persistence of amorphous dust around some young stars and an ultrafast amorphous to crystalline dust transition in HD 163296 that leads to forsterite grains with numerous silica inclusions. These dust evolution processes to form forsterite, enstatite {+-} tridymite could occur due to amorphous magnesiosilica dust precursors with a serpentine- or smectite-dehydroxylate composition.

  7. PETROLOGIC CONSTRAINTS ON AMORPHOUS AND CRYSTALLINE MAGNESIUM SILICATES: DUST FORMATION AND EVOLUTION IN SELECTED HERBIG Ae/Be SYSTEMS

    International Nuclear Information System (INIS)

    Rietmeijer, Frans J. M.; Nuth, Joseph A.

    2013-01-01

    The Infrared Space Observatory, Spitzer Space Telescope, and Herschel Space Observatory surveys provided a wealth of data on the Mg-silicate minerals (forsterite, enstatite), silica, and ''amorphous silicates with olivine and pyroxene stoichiometry'' around Herbig Ae/Be stars. These incredible findings do not resonate with the mainstream Earth Sciences because of (1) disconnecting ''astronomical nomenclature'' and the long existing mineralogical and petrologic terminology of minerals and amorphous materials, and (2) the fact that Earth scientists (formerly geologists) are bound by the ''Principle of Actualism'' that was put forward by James Hutton (1726-1797). This principle takes a process-oriented approach to understanding mineral and rock formation and evolution. This paper will (1) review and summarize the results of laboratory-based vapor phase condensation and thermal annealing experiments, (2) present the pathways of magnesiosilica condensates to Mg-silicate mineral (forsterite, enstatite) formation and processing, and (3) present mineralogical and petrologic implications of the properties and compositions of the infrared-observed crystalline and amorphous dust for the state of circumstellar disk evolution. That is, the IR-observation of smectite layer silicates in HD142527 suggests the break-up of asteroid-like parent bodies that had experienced aqueous alteration. We discuss the persistence of amorphous dust around some young stars and an ultrafast amorphous to crystalline dust transition in HD 163296 that leads to forsterite grains with numerous silica inclusions. These dust evolution processes to form forsterite, enstatite ± tridymite could occur due to amorphous magnesiosilica dust precursors with a serpentine- or smectite-dehydroxylate composition.

  8. The depositional environment and petrology of the White Rim Sandstone Member of the Permian Cutler Formation, Canyonlands National Park, Utah

    Science.gov (United States)

    Steele-Mallory, B. A.

    1982-01-01

    The White Rim Sandstone Member of the Cutler Formation of Permian age in Canyonlands National Park, Utah, was deposited in coastal eolian and associated interdune environments. This conclusion is based on stratigraphic relationships primary sedimentary structures, and petrologic features. The White Rim consists of two major genetic units. The first represents a coastal dune field and the second represents related interdune ponds. Distinctive sedimentary structures of the coastal dune unit include large- to medium-scale, unidirectional, tabular-planar cross-bedding; high-index ripples oriented parallel to dip direction of the foresets; coarse-grained lag layers; avalanche or slump marks; and raindrop impressions. Cross-bedding measurements suggest the dunes were deposited as transverse ridges by a dominantly northwest to southeast wind. Distinctive sedimentary structures of the interdune pond unit include wavy, horizontally laminated bedding, adhesion ripples, and desiccation polygons. These features may have been produced by alternate wetting and drying of sediment during water-table fluctuations. Evidence of bioturbation is also present in this unit. Petrologic characteristics of the White Rim helped to define the depositional environment as coastal. A crinoid fragment was identified at one location; both units are enriched in heavy minerals, and small amounts of well rounded, reworked glauconite were found in the White Rim throughout the study area. Earlier work indicates that the White Rim sandstone is late Wolfcampian to early Leonardian in age. During this time, the Canyonlands area was located in a depositional area alternately dominated by marine and nonmarine environments. Results of this study suggest the White Rim represents a coastal dune field that was deposited by predominantly on-shore winds during a period of marine transgression.

  9. Petrology, magnetostratigraphy and geochronology of the Miocene volcaniclastic Tepoztlán Formation: implications for the initiation of the Transmexican Volcanic Belt (Central Mexico)

    OpenAIRE

    Lenhardt, Nils; Böhnel, Harald; Wemmer, Klaus; Torres-Alvarado, Ignacio; Hornung, Jens; Hinderer, Matthias

    2010-01-01

    The volcaniclastic Tepoztlán Formation (TF) represents an important rock record to unravel the early evolution of the Transmexican Volcanic Belt (TMVB). Here, a depositional model together with a chronostratigraphy of this Formation is presented, based on detailed field observations together with new geochronological, paleomagnetic, and petrological data. The TF consists predominantly of deposits from pyroclastic density currents and extensive epiclastic products such as tuffaceous sandstones...

  10. Mineralogy and organic petrology of oil shales in the Sangkarewang Formation, Ombilin Basin, West Sumatra, Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Fatimah [School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney 2052 (Australia)]|[Centre for Geological Resources, Department of Mines and Energy, Jalan Soekarno Hatta No. 444, Bandung 40254 (Indonesia); Ward, Colin R. [School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney 2052 (Australia)

    2009-01-31

    The Ombilin Basin is filled by late Eocene to early Oligocene marginal fan deposits (Brani Formation) and lacustrine shales (Sangkarewang Formation), unconformably overlain by a late Oligocene to early Miocene fluvial sequence (Sawahlunto and Sawahtambang Formations) and capped by an early to mid-Miocene marine sequence (Ombilin Formation). Significant oil shale deposits occur in the Sangkarewang Formation, intercalated with thin laminated greenish-grey calcareous sandstones. X-ray diffraction shows that the sediments consist mainly of quartz, feldspar, carbonates and a range of clay minerals, together in some cases with minor proportions of sulphides, evaporites and zeolites. Feldspar and non-kaolinite clay minerals decrease up the sequence, relative to kaolinite, suggesting a changing sediment source as the basin was filled. Calcite, thought to be mainly of authigenic origin, is also more abundant in the middle and upper parts of the sequence. The organic matter in the oil shales of the sequence is dominated by liptinite macerals, particularly alginite (mainly lamalginite) and sporinite. Cutinite also occurs in some samples, along with resinite and traces of bituminite. The dominance of lamalginite in the liptinite components suggests that the material can be described as a lamosite. Samples from the Sangkarewang Formation have vitrinite reflectance values ranging between 0.37% and 0.55%. These are markedly lower than the vitrinite reflectance for coal from the overlying Sawahlunto Formation (0.68%), possibly due to suppression associated with the abundant liptinite in the oil shales. Fischer assay data on outcrop samples indicate that the oil yield is related to the organic carbon content. Correlations with XRD data show that, with one exception, the oil yield and organic carbon can also be correlated directly to the abundance of carbonate (calcite) and inversely to the abundance of quartz plus feldspar. This suggests that the abundance of algal material in the

  11. Organic petrology and Rock-Eval characteristics in selected surficial samples of the Tertiary Formation, South Sumatra Basin

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    M. H. Hermiyanto

    2014-06-01

    Full Text Available http://dx.doi.org/10.17014/ijog.vol4no3.20096Organic petrologic data of the DOM of Talangakar and Muaraenim Formations show that the organic matter consisting mainly of vitrinite group is essentially composed of telocollinite (1.0 – 70.8 % and desmocollinite (0.8 – 66.6 % with minor telinite (0.6 – 9.4 %, detrovitrinite (0.6 – 6.0 %, and cor- pocollinite (0.6 – 2.0 %. Minor exinite (0.4 – 7.8 % and inertinite (0.4 – 8.0 % are also determined. However, mineral matter varies from 0.6 – 99.44 %. Downwards, the increase in vitrinite reflectance (0.33 – 0.48 % is concomitant with the depth of each formation. Furthermore, based on Rock-eval pyrolysis, TOC value of the Talangakar Formation ranges from 0.09 – 15.38 %, Gumai 0.34 – 0.39 %, Airbenakat 0.32 – 4.82 %, and Muaraenim between 0.08 – 15.22 %. Moreover the PY (Potential Yield value variation of the Talangakar, Gumai, Airbenakat, and Muaraenim Formations are between 0.04 – 36.61 mg HC/g rock, 0.53 – 0.81 mg HC/g rock, 0.1 – 4.37 mg HC/g rock, and 0.07 – 129.8 mg HC/g rock respectively. Therefore, on the basis of those two parameters, the four formations are included into a gas - oil prone source rock potential. However, the Talangakar and Muaraenim Formations are poor to excellent category, whereas the Air Benakat tends to indicate a poor – fair category and Gumai Formation are only within a poor category. Tmax value of the Talangakar ranges from 237 – 4380 C, Gumai 316 – 3590 C, Airbenakat 398 – 4340 C with exceptions of 4970 C and 5180 C, and Muaraenim Forma- tions 264 – 4250 C. The Talangakar Formation contains kerogen Type II dan III, with the HI (Hydrogen Index value varies from 45.16 – 365.43. However two samples show value of 0. The organic content of the Gumai and Air Benakat Formations are included into kerogen type III, with HI value ranges from11.87 – 40.82, and 19 – 114 respectively. Moreover the Muaraenim Formation has two category of

  12. Petrology and geochemistry of Granitoids at Khanchay-Aliabad region, Tarom sub-zone, East of Zanjan

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    Arefeh Saiedi

    2018-03-01

    Full Text Available Khanchay-Aliabad area as a part of Tarom magmatic belt contains some shallow depth intrusions which are intruded the Eocene volcanic- sedimentary rocks and have very close association with Cu mineralization. The Eocene volcanic- sedimentary rocks include alternation of basalt, basaltic andesite and andesite, various kinds of tuff, tuffaceous sandstone, sandstone, siltstone and occasionally shale. Petrographical studies demonstrate that intrusions are pyroxene quartz monzonite and olivine gabbro in composition. The Khanchay pyroxene quartz monzonite have porphyritic to porphyroidic, hetero-granular to sereitic, ophitic and sub- ophitic textures and composed of plagioclase, clinopyroxene, hornblende, quartz, K-feldspar and biotite. The Aliabad pyroxene quartz monzonite shows porphyritic to porphyroidic textures composing of plagioclase, clinopyroxene and hornblende in the quartz- feldspatic matrix. The Khanchay olivine gabbro is characterized by the presence of coarse grained granular, ophitic and sub- ophitic textures as well as the occurrence of plagioclase, clinopyroxene and olivine. Geochemical studies indicate that the Khanchay- Aliabad pyroxene quartz monzonitic intrusions have SiO2 content varying from 59.58 to 61.34 %. These intrusions have high- K calc- alkaline nature and are classified as I-type metaluminous granitoids. Their similar patterns on spider diagrams are indication of genetic relation of these intrusions. On these diagrams LILEs (Ba, K, Th and Pb enrichment along with negative anomalies of HFSEs (Nb and Ti are observed. Moreover, the Chondrite normalized REE patterns demonstrate LREE enrichment with high ratio of LREE/HREE and Lan/Ybn ratio ranging from 3.08 to 3.72. The overall  field investigation, petrological and geochemical studies as well as  tectonic setting discrimination diagrams confirm that the Khanchay- Aliabad high-K intrusions were formed from a subduction related metasomatized lithospheric mantle in a post

  13. Petrology and tectonics of Phanerozoic continent formation: From island arcs to accretion and continental arc magmatism

    Science.gov (United States)

    Lee, C.-T.A.; Morton, D.M.; Kistler, R.W.; Baird, A.K.

    2007-01-01

    Mesozoic continental arcs in the North American Cordillera were examined here to establish a baseline model for Phanerozoic continent formation. We combine new trace-element data on lower crustal xenoliths from the Mesozoic Sierra Nevada Batholith with an extensive grid-based geochemical map of the Peninsular Ranges Batholith, the southern equivalent of the Sierras. Collectively, these observations give a three-dimensional view of the crust, which permits the petrogenesis and tectonics of Phanerozoic crust formation to be linked in space and time. Subduction of the Farallon plate beneath North America during the Triassic to early Cretaceous was characterized by trench retreat and slab rollback because old and cold oceanic lithosphere was being subducted. This generated an extensional subduction zone, which created fringing island arcs just off the Paleozoic continental margin. However, as the age of the Farallon plate at the time of subduction decreased, the extensional environment waned, allowing the fringing island arc to accrete onto the continental margin. With continued subduction, a continental arc was born and a progressively more compressional environment developed as the age of subducting slab continued to young. Refinement into a felsic crust occurred after accretion, that is, during the continental arc stage, wherein a thickened crustal and lithospheric column permitted a longer differentiation column. New basaltic arc magmas underplate and intrude the accreted terrane, suture, and former continental margin. Interaction of these basaltic magmas with pre-existing crust and lithospheric mantle created garnet pyroxenitic mafic cumulates by fractional crystallization at depth as well as gabbroic and garnet pyroxenitic restites at shallower levels by melting of pre-existing lower crust. The complementary felsic plutons formed by these deep-seated differentiation processes rose into the upper crust, stitching together the accreted terrane, suture and former

  14. Petrological-geochemical characteristics of coarse-grained clastic sedimentary rocks of Quantou Formation, Cretaceous in Songliao basin and their geological significance

    International Nuclear Information System (INIS)

    Wang Gan; Zhang Bangtong

    2005-01-01

    Clastic sedimentary rocks of Quantou Formation, Cretaceous in Qing-an area, Songliao basin are mainly composed of sandstone, mudstone and siltstone. The petrological-chemical analysis of clastic sedimentary rocks from Quantou Formation, Cretaceous indicates that their lithology mainly consists of arkose, shale and minor rock debris sandstone and greywacke by chemical classification of bulk elements. REE distribution pattern displays the apparent enrichment of LREE and negative anomaly of Eu and is similar to that of NASC and PAAS. The ratio of trace-element in sedimentary rocks to that of upper crust shows gentle character. All the above features indicate that these sedimentary rocks were slowly deposited under weakly active tectonic setting. They are sediments typical for passive continental margin and active continental margin. It is suggested that material source of clastic sediments of Quantou Formation, Cretaceous in Qing-an area, Songliao basin was originated from Hercynian granite of Zhangguangchai Mountain, and the granite was originated from upper crust. (authors)

  15. The formation of FeO-rich pyroxene and enstatite in unequilibrated enstatite chondrites: A petrologic-trace element (SIMS) study

    Science.gov (United States)

    Weisberg, M. K.; Prinz, M.; Fogel, R. A.; Shimizu, N.

    1993-01-01

    Enstatite (En) chondrites record the most reducing conditions known in the early solar system. Their oxidation state may be the result of condensation in a nebular region having an enhanced C/O ratio, reduction of more oxidized materials in a reducing nebula, reduction during metamorphic reheating in a parent body, or a combination of these events. The presence of more oxidized Fe-rich silicates, two types of En (distinguished by red and blue CL), and the juxtaposition of FeO-rich pyroxenes (Fe-pyx) surrounded by blue En (enstatite) in the UEC's (unequilibrated enstatite chondrites) is intriguing and led to the examination of the question of enstatite chondrite formation. Previously, data was presented on the petrologic-geochemical characteristics of the Fe-pyx and coexisting red and blue En. Here minor and trace element abundances (determined by ion probe-SIMS) on these three types of pyroxenes are reported on in the following meteorites: Kota Kota and LEW87223 (EH3), MAC88136 (EL3), St. Marks (EH4), and Hvittis (EL6). More data are currently being collected.

  16. Towards modern petrological collections

    NARCIS (Netherlands)

    Kriegsman, L.M.

    2004-01-01

    Petrological collections result from sampling for academic research, for aesthetic or commercial reasons, and to document natural diversity. Selection criteria for reducing and enhancing collections include adequate documentation, potential for future use, information density, time and money

  17. Rapid formation of a sea ice barrier east of Svalbard

    Science.gov (United States)

    Nghiem, S. V.; van Woert, M. L.; Neumann, G.

    2005-11-01

    Daily SeaWinds scatterometer images acquired by the QuikSCAT satellite show an elongated sea ice feature that formed very rapidly (˜1-2 days) in November 2001 east of Svalbard over the Barents Sea. This sea ice structure, called "the Svalbard sea ice barrier," spanning approximately 10° in longitude and 2° in latitude, restricts the sea route and poses a significant navigation hazard. The secret of its formation appears to lie in the bottom of the sea: A comparison between bathymetry from the International Bathymetric Chart of the Arctic Ocean data and the pattern of sea ice formation from scatterometer data reveals that the sea ice barrier conforms well with and stretches above a deep elongated channel connecting the Franz Josef-Victoria Trough to the Hinlopen Basin between Svalbard and Franz Josef Land. Historic hydrographic data from this area indicate that this sea channel contains cold Arctic water less than 50 m below the surface. Strong and persistent cold northerly winds force strong heat loss from this shallow surface layer, leading to the rapid formation of the sea ice barrier. Heat transfer rates estimated from European Centre for Medium-Range Weather Forecasts temperature and wind data over this region suggest that the surface water along the deep channel can be rapidly cooled to the freezing point. Scatterometer results in 1999-2003 show that sea ice forms in this area between October and December. Understanding the ice formation mechanisms helps to select appropriate locations for deployment of buoys measuring wind and air-sea temperature profile and to facilitate ice monitoring, modeling, and forecasting.

  18. Logbooks from the English East India Company voyages digitized in keyed format from 1789 to 1834

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This collection of keyed Logbooks from the East India Company voyages are formatted in a common digitized format. Data include daily instrumental measurements and...

  19. Petrologic significance of Fe-rich staurolite in pelitic schists of the Silgará Formation, Santander Massif

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Ríos

    2016-01-01

    Full Text Available Medium grade metapelites of the Silgará Formation at the Santander Massif (Colombian Andes have been affected by a medium-pressure/high-temperature Barrovian type of metamorphism, developing a sequence of metamorphic zones (biotite, garnet, staurolite and sillimanite. These rocks record a complex tectonometamorphic evolution and reaction history. Metapelitic rocks from the staurolite zone are typically foliated, medium- to coarse-grained, pelitic to semipelitic schists that contain the mineral assemblage biotite + garnet + staurolite ± kyanite; all contain muscovite + quartz + plagioclase with minor K-feldspar, tourmaline, apatite, zircon, epidote, calcite, and Fe–Ti oxides. Field and microscopic evidences reveal that Fe-rich staurolite in pelitic schists is involved in several chemical reactions, which explains its formation and transformation to other minerals, which are very important to elucidate the reaction history of the Silgará Formation metapelites.   Significado Petrológico de Estaurolita Rica en Fe en Esquistos Pelíticos de la Formación Silgará, Macizo de Santander   Resumen Medium grade metapelites of the Silgará Formation en el Macizo de Santander (Andes Colombianos han sido afectadas por un metamorfismo de tipo Barroviense, el cual se ha producido en condiciones de media presión y alta temperatura, desarrollando una secuencia de zonas metamórficas (biotita, granate, estaurolita y silimanita. Estas rocas registran una evolución tectono-metamórfico e historia reacción compleja. Las metapelitas de la zona de la estaurolita están representadas por esquistos pelíticos a semipelíticos de grano medio a grueso típicamente foliados que contienen la paragénesis mineral biotita + granate + estaurolita ± cianita; todos contienen moscovita + cuarzo + plagioclasa con menor feldespato potásico, turmalina, apatito, zircón, epidota, calcita, y óxidos de Fe-Ti. Evidencias de campo y microscópicas revelan que la estaurolita

  20. Organic petrology and geochemistry of mudrocks from the lacustrine Lucaogou Formation, Santanghu Basin, northwest China: Application to lake basin evolution

    Science.gov (United States)

    Hackley, Paul C.; Fishman, Neil; Wu, Tao; Baugher, Gregory

    2016-01-01

    Exploration for tight oil in the frontier Santanghu Basin of northwest China has resulted in recent commercial discoveries sourced from the lacustrine Upper Permian Lucaogou Formation, already considered a “world class source rock” in the Junggar Basin to the west. Here we apply an integrated analytical program to carbonate-dominated mudrocks from the Lucaogou Formation in Santanghu Basin to document the nature of organic matter (OM) in the context of an evolving lake system. The organic-rich samples (TOC 2.8–11.4 wt%; n = 10) were widely spaced from an ~ 200 m cored section, interpreted from textural and mineralogical evidence to document transition from a lower under-filled to an overlying balanced-filled lake. Organic matter is dominated by moderate to strongly fluorescent amorphous material with Type I geochemical signature (HI values 510–755; n = 10) occurring in a continuum from lamellar stringers, 10–20 μm thick, some ≥ 1 mm in length (possible microbial mat; preserved only in lower under-filled section) to finely-disseminated amorphous groundmass intimately intermixed with mineral matrix. Biomarkers for methanotrophs and photosynthetic cyanobacteria indicate a complex microbial consortium. A unicellular prasinophyte green alga(?), similar to Tasmanites in marine rocks, is present as discrete flattened discs 50–100 μm in diameter. Type III OM including vitrinite (some fluorescent) and inertinite also is abundant. Solid bitumen, indicating local kerogen conversion, fills voids and occurs throughout the cored section. Vitrinite reflectance values are 0.47–0.58%, consistent with strong OM fluorescence but may be “suppressed”. Other proxies, e.g., biomarker parameters, indicate the Lucaogou Formation is in the early oil window at this location. On average, slightly more amorphous OM and telalginite are present in the lower section, consistent with a shallow, stratified, saline environment with low sediment dilution. More

  1. Petrologic Characteristics of the Lunar Surface.

    Science.gov (United States)

    Wang, Xianmin; Pedrycz, Witold

    2015-11-27

    Petrologic analysis of the lunar surface is critical for determining lunar formation and evolution. Here, we report the first global petrologic map that includes the five most important lunar lithological units: the Ferroan Anorthositic (FAN) Unit, the Magnesian Suite (MS) Unit, the Alkali Suite (AS) Unit, the KREEP Basalt (KB) Unit and the Mare Basalt (MB) Unit. Based on the petrologic map and focusing on four long-debated and important issues related to lunar formation and evolution, we draw the following conclusions from the new insights into the global distribution of the five petrologic units: (1) there may be no petrogenetic relationship between MS rocks and KB; (2) there may be no petrogenetic link between MS and AS rocks; (3) the exposure of the KREEP component on the lunar surface is likely not a result of MB volcanism but is instead mainly associated with the combined action of plutonic intrusion, KREEP volcanism and celestial collision; (4) the impact size of the South Pole-Aitken basin is constrained, i.e., the basin has been excavated through the whole crust to exhume a vast majority of lower-crustal material and a very limited mantle components to the lunar surface.

  2. Petrology of arkosic sandstones, Pennsylvanian Minturn Formation and Pennsylvanian and Permian Sangre de Cristo Formation, Sangre de Cristo Range, Colorado - data and preliminary interpretations

    Science.gov (United States)

    Lindsey, D.A.

    2000-01-01

    This report describes the mineral and chemical composition of immature, arkosic sandstones of the Pennsylvanian Minturn and Pennsylvanian and Permian Sangre de Cristo Formations, which were derived from the Ancestral Rocky Mountains. Located in the Sangre de Cristo Range of southern Colorado, the Minturn and Sangre de Cristo Formations contain some of the most immature, sodic arkoses shed from the Ancestral Rocky Mountains. The Minturn Formation was deposited as fan deltas in marine and alluvial environments; the Sangre de Cristo Formation was deposited as alluvial fans. Arkoses of the Minturn and Sangre de Cristo Formations are matrix-rich and thus may be properly considered arkosic wackes in the terminology of Gilbert (Williams and others, 1954). In general, potassium feldspar and plagioclase are subequal in abundance. Arkose of the Sangre de Cristo Formation is consistently plagioclase-rich; arkose from the Minturn Formation is more variable. Quartz and feldspar grains are accompanied by a few percent rock fragments, consisting mostly of intermediate to granitic plutonic rocks, gneiss, and schist. All of the rock fragments seen in sandstone are present in interbedded conglomerate, consistent with derivation from a Precambrian terrane of gneiss and plutonic rocks much like that exposed in the present Sangre de Cristo Range. Comparison of mineral and major oxide abundances reveals a strong association of detrital quartz with SiO2, all other detrital minerals (totaled) with Al2O3, potassium feldspar plus mica with K2O, and plagioclase with Na2O. Thus, major oxide content is a good predictor of detrital mineralogy, although contributions from matrix and cement make these relationships less than perfect. Detrital minerals and major oxides tend to form inverse relationships that reflect mixtures of varying quantities of minerals; when one mineral is abundant, the abundance of others declines by dilution. In arkose of the Minturn and Sangre de Cristo Formations, the

  3. Regional conflict formations: is the Middle East next?

    NARCIS (Netherlands)

    Leenders, R.

    2007-01-01

    As Iraq is plunging into civil war, politics and violence in the Middle East are increasingly perceived to be highly interconnected and entwined. This article offers an attempt to understand the nature and scope of this regional interconnectedness involving three of the region's states—Iraq, Syria

  4. Catahoula Formation as uranium source rock in East Texas

    International Nuclear Information System (INIS)

    Ledger, E.B.; Tieh, T.T.; Rowe, N.W.

    1984-01-01

    The Oligocene-Miocene Catahoula Formation of the Texas Gulf coastal plain is a fluvial and lacustrine volcaniclastic unit composed of normal fluvial material mixed with distal rhyolitic air-fall ash. In the lower Texas Gulf coastal plain, it consists of stream-transported detritus from the volcanic source area in Trans-Pecos Texas and adjacent Mexico. This volcaniclastic component has altered to release uranium to mineralization processes in the lower Gulf Coast, but there has not been uranium production in the middle and upper Gulf Coast. To evaluate the potential of the upper Texas Gulf coastal plain for uranium ore deposits, a geochemical study was undertaken. The Catahoula Formation was analyzed for U, Th, K, Rb, Sr, Zr, and Ti to estimate the nature of volcanic glass and its abundance and alteration. Concentrations from three key outcrops were compared. They were also compared to samples from a volcanic area in Trans-Pecos Texas, which is chemically appropriate as a source for the volcanic material in the Catahoula Formation. In the lower Texas Gulf coastal plain, where uranium is produced, the glassy volcanic material has been pervasively altered, but in the upper coastal plain much glass remains. Because glass alteration is necessary for uranium release and concentration, the potential is low for large, shallow uranium ore bodies in the upper Texas Gulf coastal plain

  5. Journal of Mineralogical and Petrological Sciences

    Science.gov (United States)

    Official journal of Japan Association of Mineralogical Sciences (JAMS), focusing on mineralogical and petrological sciences and their related fields. Journal of Mineralogical and Petrological Sciences (JMPS) is the successor journal to both “Journal of Mineralogy, Petrology and Economic Geology” and “Mineralogical Journal”. Journal of Mineralogical and Petrological Sciences (JMPS) is indexed in the ISI database (Thomson Reuters), the Science Citation Index-Expanded, Current Contents/Physical, Chemical & Earth Sciences, and ISI Alerting Services.

  6. The role of territorial marketing in the formation of Russian Far East social and economic development complex

    Directory of Open Access Journals (Sweden)

    Bacherikova M. L.

    2016-11-01

    Full Text Available the article describes those areas of marketing tools which used in the complex of measures on Far East development. The role of territory marketing in formation of conditions for social and economic development of Far East macroregion is determinated; proposals on marketing approach to territory management in order to increase its competitiveness and attractiveness are formulated.

  7. Catahoula formation as a source of sedimentary uranium deposits in east Texas

    International Nuclear Information System (INIS)

    Ledger, E.B.; Tieh, T.T.

    1983-01-01

    Volcanic glass-rich mudstone and siltstone samples from the Oligocene/Miocene Catahoula formation of Jasper County, Texas, and coeval volcaniclastic rock samples from Trans-Pecos, Texas, have been compared as to U, Th, Zr, Ti, K, Rb, and Sr contents. Uranium is slightly greater in the distal ash (5.85 ppM U) compared to the Trans-Pecos samples (average 5.41 ppM U). Diagenetic and pedogenetic alteration of Catahoula volcanic glass releases uranium to solution and, under favorable conditions, this uranium may accumulate to form ore bodies. Uranium has been produced from such ore bodies in south Texas, but economic deposits are not known in east Texas. Significant differences between south and east Texas include: (1) a greater amount of volcanic debris delivered to south Texas, both as air-fall ash and stream-transported material, (2) delivery of only air-fill ash to east Texas, (3) the possibility of more petroleum-related reductants such as H 2 S in south Texas, and (4) pervasive glass alteration with subsequent uranium release in south Texas due to late calichification. These differences argue against economic deposits of the south Texas type being found in east Texas. If economic deposits occur they are likely to be far downdip making exploration difficult and expensive

  8. Environmental Sensitivity Index (ESI) Atlas: East Florida, maps in portable document format, Volume 1, Volume 2 (NODC Accession 0004150)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set comprises the Environmental Sensitivity Index (ESI) maps in Portable Document Format (.PDF) for the shoreline of East Florida (to encompass the coastal...

  9. Petrology and geochemistry of the orbicular granitoid of Caldera, northern Chile. Models and hypotheses on the formation of radial orbicular textures

    Science.gov (United States)

    Díaz-Alvarado, Juan; Rodríguez, Natalia; Rodríguez, Carmen; Fernández, Carlos; Constanzo, Ítalo

    2017-07-01

    The orbicular granitoid of Caldera, located at the northern part of the Chilean Coastal Range, is a spectacular example of radial textures in orbicular structures. The orbicular body crops out as a 375 m2 tabular to lensoidal intrusive sheet emplaced in the Lower Jurassic Relincho pluton. The orbicular structures are 3-7 cm in diameter ellipsoids hosted in a porphyritic matrix. The orbicules are comprised by a Qtz-dioritic core (3-5 cm in diameter) composed by Pl + Hbl + Qtz + Bt ± Kfs with equiaxial textures and a gabbroic shell (2-3 cm in diameter) characterized by feathery and radiate textures with a plagioclase + hornblende paragenesis. The radial shell crystals are rooted and orthogonally disposed in the irregular contact with the core. The radial shell, called here inner shell, is in contact with the granodioritic equiaxial interorbicular matrix through a 2-3 mm wide poikilitic band around the orbicule (outer shell). The outer shell and the matrix surrounding the orbicules are characterized by the presence of large hornblende and biotite oikocrystals that include fine-grained rounded plagioclase and magnetite. The oikocrystals of both the outer shell and the matrix have a circumferential arrangement around the orbicule, i.e. orthogonal to the radial inner shell. The coarse-grained granodioritic interorbicular matrix present pegmatitic domains with large acicular hornblende and K-feldspar megacrysts. This work presents a review of the textural characteristics of the orbicules and a complete new mineral and whole-rock geochemical study of the different parts of the orbicular granitoid, together with thermobarometric and crystallographic data, and theoretical modeling of the crystallization and element partitioning processes. We propose a model for the formation of the orbicular radial textures consisting of several processes that are suggested to occur fast and consecutively: superheating, volatile exsolution, undercooling, geochemical fractionation and

  10. The formation of a cold-core eddy in the East Australian Current

    Science.gov (United States)

    Macdonald, H. S.; Roughan, M.; Baird, M. E.; Wilkin, J.

    2016-02-01

    Cold-core eddies (CCEs) frequently form in western boundary currents and can affect continental shelf processes. It is not always clear, however, if baroclinic or barotropic instabilities contribute more to their formation. The Regional Ocean Modelling System (ROMS) is used to investigate the ocean state during the formation of a CCE in the East Australian Current (EAC) during October 2009. The observed eddy initially appeared as a small billow (approx. 50 km in length) that perturbed the landward edge of the EAC. The billow grew into a mesoscale CCE (approx. 100 km in diameter), diverting the EAC around it. A ROMS simulation with a realistic wind field reproduced a similar eddy. This eddy formed from negative vorticity waters found on the continental shelf south of the EAC separation point. A sensitivity analysis is performed whereby the impact of 3 different wind forcing scenarios, upwelling, downwelling, and no winds, are investigated. A CCE formed in all wind scenarios despite the wind induced changes in hydrographic conditions in the continental shelf and slope waters. As such, the source of energy for eddy formation did not come from the interactions of wind with the continental shelf waters. Analysis of strain and energy transformation confirms this by showing that the prevailing source of CCE energy was kinetic energy of the offshore EAC. These results clearly link the formation of the CCE to the swift flowing EAC and barotropic instabilities.

  11. Electrical Resistivity Models in Geological Formations in the Southern Area of the East of Cuba

    Directory of Open Access Journals (Sweden)

    José Antonio García-Gutiérrez

    2017-04-01

    Full Text Available The purpose of this study is to develop electrical resistivity models in geological formations of greater interest for geological engineering in the southern area of the East of Cuba. A procedure for the generalization of the geo-electrical database was prepared to generate the referred geo-electrical models. A total of 38 works with 895 vertical electrical surveys, of which 317 (35.4% located near (parametrical drills. Three models for the Paso Real formation and one for the Capdevila, the most distributed in the region under investigation were defined. The surface quartz sands from the municipality of Sandino were identified to have higher electrical resistivity averages (1241 Ω•m, while they do not exceed 86 Ω•m in the lower horizons to resolve basic tasks of the geological engineering investigations. The assessment of the cover clayey sandy soils was satisfactory in both geological formations while the determination of the water table depth was unfavorable. The remaining tasks varied between relatively favorable to unfavorable according to the geological formations.

  12. Stratigraphy, provenance, and diagenesis of the Cretaceous Horse Range Formation, east Otago, New Zealand

    International Nuclear Information System (INIS)

    Mitchell, M.; Craw, D.; Landis, C.A.; Frew, R.

    2009-01-01

    The Horse Range Formation is a structurally controlled late Early Cretaceous to early Late Cretaceous nonmarine unit in east Otago, South Island, New Zealand, containing immature lithic debris. Clasts are generally rounded, with only minor subangular material. The formation contains clasts derived from two principal basement sources: schist and greywacke. Schist debris is most abundant at the base of the described section, and this material is dominated (>60%) by quartz from the greenschist facies core of the Otago Schist belt. Conglomerates with >70% greywacke clasts constitute most of the upper part of the Horse Range Formation. These greywacke conglomerates have a matrix of sand derived mainly from schist. A 60 m thick wedge of quartz-rich, locally carbonaceous sand occurs interlayered with greywacke conglomerates. The Horse Range Formation rests on sub-greenschist facies semischist, which forms only a small proportion ( 18 O SMOW near +24 permil and δ 13 C PDB near -2 permil, and was partly dissolved and redeposited from the immature basement debris (metamorphic calcite) and partly introduced from overlying Late Cretaceous and Teriary marine sediments by groundwater. (author). 43 refs., 11 figs., 1 tab.

  13. Petrography and petrology of the Hamadan pegmatites

    International Nuclear Information System (INIS)

    Valizadeh, M.V.; Torkian, A.

    2000-01-01

    Petrological investigation on the pegmatites of Hamadan area was carried out for their abundance, mineralogical variations and their distribution. They reveal the genesis of Granitoid of Alvand in western parts of Iran in Sanandaj - Sirjan metamorphic belt. Field investigations show that pegmatites are mainly dispersed both on north and south of Alvand mass. They mainly consist of Graphic - pegmatites, Tourmaline Pegmatites, Aluminosilicate - pegmatites and Quartz veins. Muscovite - Aluminosilicate pegmatites are located only in south and outside of granitoid mass, for example near Dehnow Asad - Ol - llah - Khan and Manga villages. Regarding to field investigation, mineralogical characteristics and based on radiometric dating the age of biotites of granitoid is a bout 70-80 M.Y. and the age of Muscovite - pegmatites is about 100 M.Y. Therefore, pegmatites are prior to Alvand emplacement. This is in accordance with pegmatites genesis idea proposed by Winkler and von Platen. So, we suppose that pegmatites of Alvand are metamorphic and their formation do not follow normal magmatic trends. Our petrologic investigation shows that as a result of movement of Arabic plate towards Iranian pa lte (SW - NE), sedimentary rocks composing of metamorphed clays (meta-sediments) in 680-800 d eg C and 2-5 kbar was melted resulting in aplitic melt to come upwards. With the present of thermal dome, transportation of water and mineralizing gas large crystals of Muscovite and Tourmaline were formed slowly and gradually pegmatites were formed. In this condition a melt from sandstone-shale source began to move upward and in different T-P condition it formed aluminosilicate pegmatites. Each of these assemblages present specific conditions of formation

  14. Mobility, Formation and Development of the Academic Profession in Science, Technology, Engineering and Mathematics in East and South East Asia

    Science.gov (United States)

    Yonezawa, Akiyoshi; Horta, Hugo; Osawa, Aki

    2016-01-01

    The academic profession contributes to shaping the capacity and identity of higher education systems. In East and Southeast Asia, there is a need for further discussion on the regional identity characteristics of the academic profession to account for its multiple origins and national and international dimensions. Data from two large-scale…

  15. Petrologic Applications of Tourmaline

    Science.gov (United States)

    London, D.; Morgan, G. B., VI; Wolf, M. B.; Guttery, B. M.

    2011-12-01

    Compositions of tourmaline reflect its chemical environment of formation. Schorl-dravite is an accessory in metapelites and persists up to the onset of anatexis. Amphibolites and marbles contain uvite, and magnesiofoitite-povandraite is distinctive of base-metal porphyries. In granitic pegmatites, schorl-dravite at the contacts evolves toward foitite and olenite (aluminous) components as Fe is depleted from the melt. Fractionation may bring residual melts to saturation in elbaite, an Li-rich component of tourmaline. Common tourmaline (schorl-dravite-olenite-foitite solid solution) possesses a wide P-T field of stability. Synthesis experiments put the upper thermal limit of common tourmaline at ~ 750°-850°C from 50 MPa to 10 GPa, and dravite has been synthesized as low as 350°C. The boron content of granitic melt or aqueous fluid in equilibrium with common tourmaline alone and with equivalent silicate mineral assemblages varies sharply with temperature according to a relationship of CB2O3melt,vapor ~ 0.0032e0.0087T(C). Common tourmaline is stable over an aSiO2 at and below saturation in Qtz; besides FeMg, its stability hinges principally on the solubility product [aAl2O3]3*[aB2O3]1.5 in vapor or melt. Surprisingly, increasing activities of H2O or fluoride components (both are present in tourmaline) destabilize common tourmaline in granitic melt, as both components form complexes with Al that reduce aAl2O3 in the melt. As a result, common tourmaline may survive anatexis when the aH2O attending melting is low. In contrast to common tourmaline, most attempts to synthesize elbaite have failed. Aluminous tourmaline containing 37 mol% Elb component has been synthesized recently, which is significant for understanding occurrences in pegmatites as well as for the potential appearance of synthetic elbaite on the gem market. Experimental calibration of δ11B between aqueous fluid and dravite at 50-500 MPa and 350°-750°C varies by only 6.1 % over this range of conditions

  16. A preliminary report on coprolites from the Late Triassic part of the Kap Stewart Formation, Jameson Land, East Greenland

    DEFF Research Database (Denmark)

    Milàn, Jesper; Clemmensen, Lars B; Adolphsen, Jan Schulz

    2012-01-01

    The basal part of the Triassic-Jurassic (Rhaetian-Sinemurian) Kap Stewart Formation, exposed at Jameson Land, East Greenland, yields an extensive coprolite collection from black, parallel-laminated mudstone (“paper shale”), representing an open lacustrine system. Preliminary investigations show t...

  17. Boundary layer new particle formation over East Antarctic sea ice – possible Hg-driven nucleation?

    Directory of Open Access Journals (Sweden)

    R. S. Humphries

    2015-12-01

    Full Text Available Aerosol observations above the Southern Ocean and Antarctic sea ice are scarce. Measurements of aerosols and atmospheric composition were made in East Antarctic pack ice on board the Australian icebreaker Aurora Australis during the spring of 2012. One particle formation event was observed during the 32 days of observations. This event occurred on the only day to exhibit extended periods of global irradiance in excess of 600 W m−2. Within the single air mass influencing the measurements, number concentrations of particles larger than 3 nm (CN3 reached almost 7700 cm−3 within a few hours of clouds clearing, and grew at rates of 5.6 nm h−1. Formation rates of 3 nm particles were in the range of those measured at other Antarctic locations at 0.2–1.1 ± 0.1 cm−3 s−1. Our investigations into the nucleation chemistry found that there were insufficient precursor concentrations for known halogen or organic chemistry to explain the nucleation event. Modelling studies utilising known sulfuric acid nucleation schemes could not simultaneously reproduce both particle formation or growth rates. Surprising correlations with total gaseous mercury (TGM were found that, together with other data, suggest a mercury-driven photochemical nucleation mechanism may be responsible for aerosol nucleation. Given the very low vapour pressures of the mercury species involved, this nucleation chemistry is likely only possible where pre-existing aerosol concentrations are low and both TGM concentrations and solar radiation levels are relatively high (∼ 1.5 ng m−3 and ≥ 600 W m−2, respectively, such as those observed in the Antarctic sea ice boundary layer in this study or in the global free troposphere, particularly in the Northern Hemisphere.

  18. Multiscalar approach to archaeological site formation at GaJj17, East Turkana, Kenya

    Science.gov (United States)

    Murray, B. M.; Ranhorn, K. L.; Colarossi, D.; Mavuso, S. S.; Dogandžić, T.; Ziegler, M. J.; Warren, S. L.; Braun, D. R.; Harris, J. W. K.

    2017-12-01

    Kenya's East Turkana region hosts a rich Plio­Pleistocene record of fossils, archaeological artifacts, and sedimentary features whose chronostratigraphic histories are often obscured by landscape changes from erosional events and tectonic activity. The Middle Stone Age (MSA) record of the Koobi Fora Formation (KF Fm.) has particularly been subjected to this complex depositional history, making it a sparse unit and, consequently, widely understudied. Stratigraphically located in between the maximum capping unconformity of the KF Fm.'s Chari tuff ( 1.39 Ma) and that of the Galana Boi Fm. ( 10 ka), the unit provides a unique window into understanding the Late Pleistocene of the region. The MSA surface scatters at archaeological site GaJj17 prompted further study into the site's age and depositional chronology. The GaJj17 ridge is locally distinguished by its cap of Late Pleistocene sands overlying strata containing tuffs likely of the Upper Burgi (2.0­-1.87 Ma) or KBS (1.87­-1.56 Ma) members. To investigate whether GaJj17's preservation is due to tectonic deformation, a broader scale examination of the structural geology was conducted through surveys and aerial imagery. Regions of deformation were identified and mapped to establish the geological history of the locality. Resultant observations and elevation data offer insight into regional faults at the root of prolonged structural alterations which have facilitated the unique preservation of MSA materials. Through a multiscalar approach it is possible to understand both the formation of GaJj17 and the underlying processes behind preservation and destruction in the changing landscape of the Turkana basin, enabling future identification of archaeological sites through proxies of elevation, regional stratigraphy, and fault mapping. This research was supported by IRES grants 1358178 and 1358200 from the U.S. National Science Foundation.

  19. Recent rift formation and impact on the structural integrity of the Brunt Ice Shelf, East Antarctica

    Directory of Open Access Journals (Sweden)

    J. De Rydt

    2018-02-01

    Full Text Available We report on the recent reactivation of a large rift in the Brunt Ice Shelf, East Antarctica, in December 2012 and the formation of a 50 km long new rift in October 2016. Observations from a suite of ground-based and remote sensing instruments between January 2000 and July 2017 were used to track progress of both rifts in unprecedented detail. Results reveal a steady accelerating trend in their width, in combination with alternating episodes of fast ( > 600 m day−1 and slow propagation of the rift tip, controlled by the heterogeneous structure of the ice shelf. A numerical ice flow model and a simple propagation algorithm based on the stress distribution in the ice shelf were successfully used to hindcast the observed trajectories and to simulate future rift progression under different assumptions. Results show a high likelihood of ice loss at the McDonald Ice Rumples, the only pinning point of the ice shelf. The nascent iceberg calving and associated reduction in pinning of the Brunt Ice Shelf may provide a uniquely monitored natural experiment of ice shelf variability and provoke a deeper understanding of similar processes elsewhere in Antarctica.

  20. Recent rift formation and impact on the structural integrity of the Brunt Ice Shelf, East Antarctica

    Science.gov (United States)

    De Rydt, Jan; Hilmar Gudmundsson, G.; Nagler, Thomas; Wuite, Jan; King, Edward C.

    2018-02-01

    We report on the recent reactivation of a large rift in the Brunt Ice Shelf, East Antarctica, in December 2012 and the formation of a 50 km long new rift in October 2016. Observations from a suite of ground-based and remote sensing instruments between January 2000 and July 2017 were used to track progress of both rifts in unprecedented detail. Results reveal a steady accelerating trend in their width, in combination with alternating episodes of fast ( > 600 m day-1) and slow propagation of the rift tip, controlled by the heterogeneous structure of the ice shelf. A numerical ice flow model and a simple propagation algorithm based on the stress distribution in the ice shelf were successfully used to hindcast the observed trajectories and to simulate future rift progression under different assumptions. Results show a high likelihood of ice loss at the McDonald Ice Rumples, the only pinning point of the ice shelf. The nascent iceberg calving and associated reduction in pinning of the Brunt Ice Shelf may provide a uniquely monitored natural experiment of ice shelf variability and provoke a deeper understanding of similar processes elsewhere in Antarctica.

  1. The Formative Years of the Modern Corporation: The Dutch East India Company VOC, 1602-1623

    NARCIS (Netherlands)

    O. Gelderblom (Oscar); A. de Jong (Abe); J. Jonker (Joost)

    2012-01-01

    textabstractWith their legal personhood, permanent capital with transferable shares, separation of ownership and management, and limited liability for both shareholders and managers, the Dutch East India Company (VOC) and subsequently the English East India Company (EIC) are generally considered a

  2. INTERACTIONS BETWEEN GABBROID AND GRANITOID MAGMAS DURING FORMATION OF THE PREOBRAZHENSKY INTRUSION, EAST KAZAKHSTAN

    Directory of Open Access Journals (Sweden)

    S. V. Khromykh

    2017-01-01

    upper rock levels. Examples of the magma interaction causing the formation of mingling structures at the middle and upper crust levels can be viewed as indicative of ‘fast’, active processes of the mantle‐crust interaction, when the mantle magmas actively drain the lithosphere and melt the substance of the lower‐middle crust. An important role is played by the temperature gradient in the sublithospheric mantle. It directly affects the degree of its melting and the volumes of basite magmas. Nonetheless, the permeability of the lithosphere is also important – the above‐described scenario is possible if the lithosphere is either thin or easily permeable due to the development of strike‐slip and extension fractures. In the Late Paleozoic, the territory of East Kazakhstan was part of the Altai collision system of hercinides. The late stages of its evolution (300–280 Ma were accompanied by large‐scale mantle and crustal magma‐ tism corresponding to the formation of the Late Palaeozoic large igneous province related to the activity of the Tarim mantle plume. The influence of the mantle plume on the lithospheric mantle led to an increase in the temperature gradient, and the lithosphere weakened by shear movements of the collapsing orogenic structure was permeable to mantle magmas, which caused the processes of mantle‐crustal interaction.

  3. Palynology and paleoecology of Sarcheshmeh and Sanganeh formations at Baghak section (east of Kopeh-Dagh

    Directory of Open Access Journals (Sweden)

    Mahjooneh Keshmiri

    2014-11-01

    Full Text Available 1-Introduction The Kopeh-Dagh as an inverted basin (Allen et al. 2003 is extended from the east of the Caspian Sea to NE Iran, north Afghanistan and Turkmenistan. Following the closure of palaeo-Tethys in the Middle Triassic and the opening of Neo-Tethys during the early to middle Jurassic, the Kopeh-Dagh basin formed during the early to middle Jurasic. Sedimentation took place continuously from the Jurassic through the Neogene time in the Kopeh-Dagh basin (Afshar-Harb 1979. The first geological study on these strata was done by Amiranian oil company from 1937 to 1938. Many biological and stratigraphical studies had been carried on later on this basin. Kalantari (1969, Seyed-Emami (1980, Seyed-Emami and Aryai (1981, Seyed-Emami et al. (1984, 1994, 1996, Immel et al (1997, Raisossadat and Mousavi-Harami (2000, Raisossadat (2004, 2006 and Mahanipour et al. (2011 are among those who studied the biostratigraphy and sedimentology of the Cretaceous strata of this basin. In this paper we report on palynological and paleoecological data from two mid-Cretaceous formations (Sarcheshmeh and Sanganeh in Baghak section situated in eastern part of Kopeh-Dagh basin. 2-Materials and Methods Fifteen samples from the Sarcheshmeh and thirty five samples from Sanganeh formation were processed palynologically. The preparation method of Traverse, 2007 was used. Cold hydrochloric (20% and hydrofluoric (50% acids were used to dissolve carbonates and silicates. The residue was neutralized and centrifuged in ZnCl2 (specific gravity 1.9, then sieved at 15 um using a nylon mesh, and mounted on microscope slides using liquid Canada balsam. Three slides were made from each sample. The microscope slides were examined under a light microscope and the index dinocysts were photographed and presented in two plates. In order to study palynofacies, in each slide numbers of organic materials including phytoclasts, marine palynomorphs and non-structural organic materials were

  4. Re-initiation of bottom water formation in the East Sea (Japan Sea) in a warming world.

    Science.gov (United States)

    Yoon, Seung-Tae; Chang, Kyung-Il; Nam, SungHyun; Rho, TaeKeun; Kang, Dong-Jin; Lee, Tongsup; Park, Kyung-Ae; Lobanov, Vyacheslav; Kaplunenko, Dmitry; Tishchenko, Pavel; Kim, Kyung-Ryul

    2018-01-25

    The East Sea (Japan Sea), a small marginal sea in the northwestern Pacific, is ventilated deeply down to the bottom and sensitive to changing surface conditions. Addressing the response of this marginal sea to the hydrological cycle and atmospheric forcing would be helpful for better understanding present and future environmental changes in oceans at the global and regional scales. Here, we present an analysis of observations revealing a slowdown of the long-term deepening in water boundaries associated with changes of water formation rate. Our results indicate that bottom (central) water formation has been enhanced (reduced) with more (less) oxygen supply to the bottom (central) layer since the 2000s. This paper presents a new projection that allows a three-layered deep structure, which retains bottom water, at least until 2040, contrasting previous results. This projection considers recent increase of slope convections mainly due to the salt supply via air-sea freshwater exchange and sea ice formation and decrease of open-ocean convections evidenced by reduced mixed layer depth in the northern East Sea, resulting in more bottom water and less central water formations. Such vigorous changes in water formation and ventilation provide certain implications on future climate changes.

  5. Petrological significance of REE in uraninite

    International Nuclear Information System (INIS)

    Feng Mingyue; Li Yuexiang; Xu Zhan.

    1992-01-01

    According to the petrological study of Zhuguangshan and Huanglongmiao granites and REE in uraninite from these granites, it can be concluded that REE contents in uraninite and granites are positively correlative; the partition characteristics of REE in uraninite are related to the acidity of initial rocks; and the fractionation degree of REE in uraninite reflects the differentiation degree of initial rocks

  6. Petrological significance of REE in uraninite

    Energy Technology Data Exchange (ETDEWEB)

    Mingyue, Feng; Yuexiang, Li; Zhan, Xu

    1992-09-01

    According to the petrological study of Zhuguangshan and Huanglongmiao granites and REE in uraninite from these granites, it can be concluded that REE contents in uraninite and granites are positively correlative; the partition characteristics of REE in uraninite are related to the acidity of initial rocks; and the fractionation degree of REE in uraninite reflects the differentiation degree of initial rocks.

  7. Petrology of the Sutherland commanage melilite intrusives

    International Nuclear Information System (INIS)

    Viljoen, K.S.

    1990-01-01

    The petrology of the Sutherland Commonage olivine melilitite intrusives have been investigated using petrographic and chemical methods. The results of the geochemical study suggest that the Commonage melilites were derived by the melting of a recently metasomatised region of the asthenosphere, probably under the influence of an ocean-island-type hotspot situated in the lower mantle

  8. Stratigraphy on Oxygen and Carbon Isotope of Paciran Formation East Java

    International Nuclear Information System (INIS)

    Premonowati; R P Koesoemadinata; Harsono-Pringgoprawiro; Wahyoe-S-Hantoro

    2004-01-01

    Paleotemperature fluctuation in tropical zone (centennial and decad al scale) has been known. It's based on stable isotopic analysis from each of unconformity zones. Those boundaries have derived on reef units of shallows marine reef complex of Paciran Formation, Tuban area in Northeast Java Basin. From 25 samples have been choosen on undeformed calcite and analyzed by oxygen and carbon stable isotope. It used to validizing a sea level changes during the formation to Reef 1 to Reef 17 from Paciran formation with sea surface temperature (SST) since 4 Ma until now. On early forming of Reef 1 to Reef 3 (since 4 Ma - 2,88 Ma), sea level occurred marine flooding surface. Since the formation of reef 4 (2,59 Ma) to Reef 8 (1,4 Ma) occurred stagnant temperature and almost to warmer condition. Then, δ 18 O have arise up drastically to 5 0/00 and shows warmer condition to Reef 8 formation, in contrary, the sea level have been arised to Reef 10 formation (0,7 Ma). The temperature have been fluctuated between 0,5 o and 1 o C until the formation of Reef 17 (Early Holocene) and continued to Reef 17 formation at 2 o C based on the rapidity sampling of Po rites sp. Wholly, in centennial scale, since the formation of Reef 4 (2,59 Ma) to Reef 17 (1 Ma), the curve of oxygen stable isotope shows decrease or cooler condition. Those condition have conducted to sea level drop since the formation to Reef 7 and Reef 8. There are 4 periods of interglacial since the formation of Reef 4. The warmer condition indicated since the formation of Reef 9, Reef 11 and Reef 17. Recently, a curve of oxygen isotopes reveals warmer drastically or sea level have been arisen. (author)

  9. Petrological cycles and caldera-forming events

    Science.gov (United States)

    Bachmann, O.; Deering, C. D.

    2012-12-01

    Many caldera-forming events can be framed within broad petrological cycles; volcanic stratigraphy typically defines a trend from mafic to more silicic magmas with time, culminating in the catastrophic evacuation of an upper crustal reservoir filled with the silicic magma, followed by a return to the eruption of more mafic magmas shortly after caldera collapse. Understanding how such cycles develop has clear implications for characterizing the current state of an active system. Here, we focus on a detailed examination of the well-exposed Quaternary Kos-Nisyros eruptive sequence (eastern Aegean arc) to frame a potential model for such cycles. On the basis of zircon U/Th/Pb ages, building the upper crustal magma chamber large enough to induce caldera collapse required at least a few hundred thousand years. This timeframe is necessary not only for the accumulation of large amounts of viscous, gas-rich silicic magma, but also to heat the upper crust sufficiently to allow the developing reservoir to be maintained above the solidus. In the Kos-Nisyros volcanic center, small eruptions precede the caldera-forming event and mark this period of thermal maturation as the system transitions from intermediate to silicic magma, reaching the most-evolved state only shortly prior to the caldera-forming event, the Kos Plateau Tuff (> 60 km3 of volatile-rich, high-silica rhyolite). The Kos Plateau Tuff was then followed by small-volume eruptions of more mafic magma (basaltic andesite, andesite, and dacites) that are characterized by a drier mineral assemblage. With time, the system transitioned back to cold, wet, high-SiO2 rhyolite. We suggest that the changes in magma composition and mineralogy following the caldera-forming event are due to a near-complete crystallization of the non-erupted mush in the upper crustal reservoir as it is abruptly decompressed during eruption. This rapid crystallization (1) leads to the formation of a porphyritic texture in the crystalline residual - a

  10. A petrological view of early Earth geodynamics

    Science.gov (United States)

    Herzberg, C.

    2003-04-01

    Xenoliths of low T Archean cratonic mantle consist mostly of harzburgite and lherzolite with geochemical depletions that are characterisitc of igneous residues. Many authors have identified the complementary magmas as komatiites. This model is re-examined in light of work presented in Herzberg & O'Hara (2002) and found to be problematic. Munro-type alumina-undepleted komatiites from Alexo, Pyke Hill, and other locations often contain olivine phenocrysts with maximum Mg# \\cong 94. Residues of fractional melting would consist of pure dunite having Mg# = 97-98, but these are not observed. Residues of equilibrium melting would also be pure dunite with Mg# = 94, but these are also not observed. Olivines with Mg# = 94 are found in rare harzburgites, indicating that residues of alumina-undepleted komatiite have either been overprinted by subsequent magmatism or they have been geodynamically eroded. Alumina-undepleted komatiites can be successfully modeled with a primary magma containing 30% MgO produced by 0.5 mass fractions of equilibrium melting of depleted peridotite. A hot plume interpretation is consistent with both the petrology and helium isotopic compositions of alumina-undepleted komatiites. But what about cratonic mantle? The FeO and MgO contents of residues of fertile mantle peridotite formed by both equilibrium and fractional melting can be predicted and applied to xenoliths of cratonic mantle in most cases. Application to xenoliths from the Kaapvaal and Slave cratons is not possible owing to a second stage of Opx enrichment, but results can be applied to most xenoliths from Siberia, Tanzania, Somerset Island, and east Greenland as they contain less than 45% SiO_2. These xenoliths are very similar to residues produced by fractional melting. Pressures of initial melting were mostly 3 to 5 GPa, but can be as high 7 GPa. Pressures of final melting were highly variable and can be as low as 1 GPa. Potential temperatures (T_P) were typically 1450 to 1600oC and

  11. Cyclic platform dolomites and platform-to-basin transition of Jefferson Formation (Frasnian), southwest Montana and east-central Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Dorobek, S.L.

    1987-08-01

    The Jefferson Formation (Frasnian) in southwestern Montana consists of cyclic sequences of shallow marine platformal dolomites that grade westward into slope/basinal facies in east-central Idaho. Regional sedimentologic characteristics of slope facies in Idaho indicate that the Jefferson platform resembled a distally steepened ramp. Slope facies consist of slope laminites with local small scale slumps and slope breccias. Shallow water platform-derived clasts are lacking in the slope breccias. Individual shallowing upward platform cycles are 25 m to < 1 m thick and consists of, in descending order: local solution-collapse breccia caps; cryptalgal dolomudstone; rare ooid dolograinstone; thin-bedded Amphipora dolowackestone; coarsely crystalline dolostones with abundant lenticular to domal stromatoporoids; and basal thin-bedded, fine-grained, shale dolostones with closely spaced hard-grounds that grade upward into burrow-homogenized, irregularly bedded dolostones.

  12. Evolution of the East Philippine Arc: experimental constraints on magmatic phase relations and adakitic melt formation

    Science.gov (United States)

    Coldwell, B.; Adam, J.; Rushmer, T.; MacPherson, C. G.

    2011-10-01

    Piston-cylinder experiments on a Pleistocene adakite from Mindanao in the Philippines have been used to establish near-liquidus and sub-liquidus phase relationships relevant to conditions in the East Philippines subduction zone. The experimental starting material belongs to a consanguineous suite of adakitic andesites. Experiments were conducted at pressures from 0.5 to 2 GPa and temperatures from 950 to 1,150°C. With 5 wt. % of dissolved H2O in the starting mix, garnet, clinopyroxene and orthopyroxene are liquidus phases at pressures above 1.5 GPa, whereas clinopyroxene and orthopyroxene are liquidus (or near-liquidus) phases at pressures 1.5 GPa) and subsequently involved the lower pressure fractionation of amphibole, plagioclase and subordinate clinopyroxene. Thus, the distinctive Y and HREE depletions of the andesitic adakites (which distinguish them from associated non-adakitic andesites) must be established relatively early in the fractionation process. Our experiments show that this early fractionation must have occurred at pressures >1.5 GPa and, thus, deeper than the Mindanao Moho. Published thermal models of the Philippine Sea Plate preclude a direct origin by melting of the subducting ocean crust. Thus, our results favour a model whereby basaltic arc melt underwent high-pressure crystal fractionation while stalled beneath immature arc lithosphere. This produced residual magma of adakitic character which underwent further fractionation at relatively low (i.e. crustal) pressures before being erupted.

  13. Wind Forced Variability in Eddy Formation, Eddy Shedding, and the Separation of the East Australian Current

    Science.gov (United States)

    Bull, Christopher Y. S.; Kiss, Andrew E.; Jourdain, Nicolas C.; England, Matthew H.; van Sebille, Erik

    2017-12-01

    The East Australian Current (EAC), like many other subtropical western boundary currents, is believed to be penetrating further poleward in recent decades. Previous observational and model studies have used steady state dynamics to relate changes in the westerly winds to changes in the separation behavior of the EAC. As yet, little work has been undertaken on the impact of forcing variability on the EAC and Tasman Sea circulation. Here using an eddy-permitting regional ocean model, we present a suite of simulations forced by the same time-mean fields, but with different atmospheric and remote ocean variability. These eddy-permitting results demonstrate the nonlinear response of the EAC to variable, nonstationary inhomogeneous forcing. These simulations show an EAC with high intrinsic variability and stochastic eddy shedding. We show that wind stress variability on time scales shorter than 56 days leads to increases in eddy shedding rates and southward eddy propagation, producing an increased transport and southward reach of the mean EAC extension. We adopt an energetics framework that shows the EAC extension changes to be coincident with an increase in offshore, upstream eddy variance (via increased barotropic instability) and increase in subsurface mean kinetic energy along the length of the EAC. The response of EAC separation to regional variable wind stress has important implications for both past and future climate change studies.

  14. Uranium mineralisation in Barapani formation of Mawbeh Area, East Khasi Hills District, Meghalaya

    International Nuclear Information System (INIS)

    Gupta, C.S.; Nagendra Kumar, M.; Majumdar, Amit; Umamaheshwar, K.

    2008-01-01

    Proterozoic Shillong Basin of Meghalaya comprises metapelites of Paleoproterozoic Tyrsad and arenaceous siliciclastics of Mesoproterozoic Barapani formations. Two major igneous activities, in the form of basic dykes/sills and younger granites of Neoproterozoic age, intruding Proterozoic sediments, are reported from Shillong Basin. Significant uranium mineralisation, with values up to 0.1% U 3 O 8 , associated with NE-SW trending shear zone in Barapani Formation is discovered at Mawbeh area, Pynursla Plateau. The mineralised Barapani has undergone hydrothermal alterations in the form of sericitisation, chloritisation, illitisation and kaolinisation. Petrographic studies reveal that the host rocks are ortho-quartzite, subfeldspathic arenites, quartz wacke, sericite phyllite, quartz-sericite-chlorite rock and quartz wacke. X-ray diffraction (XRD) studies of radioactive Barapani quartzite revealed the presence of uraninite. (author)

  15. The Jurassic of Denmark and Greenland: Shallow marine syn-rift sedimentation: Middle Jurassic Pelion Formation, Jameson Land, East Greenland

    Directory of Open Access Journals (Sweden)

    Engkilde, Michael

    2003-10-01

    Full Text Available The Middle Jurassic Pelion Formation – Fossilbjerget Formation couplet of Jameson Land, East Greenland, is a well-exposed example of the Middle Jurassic inshore–offshore successions characteristicof the rifted seaways in the Northwest European – North Atlantic region. Early Jurassic deposition took place under relatively quiet tectonic conditions following Late Permian – earliest Triassic and Early Triassic rift phases and the Lower Jurassic stratal package shows an overall layer-cake geometry. A long-term extensional phase was initiated in Middle Jurassic (Late Bajocian time, culminated in the Late Jurassic (Kimmeridgian–Volgian, and petered out in the earliest Cretaceous (Valanginian. The Upper Bajocian – Middle Callovian early-rift succession comprises shallow marine sandstones of the Pelion Formation and correlative offshore siltstones of theFossilbjerget Formation. Deposition was initiated by southwards progradation of shallow marine sands of the Pelion Formation in the Late Bajocian followed by major backstepping in Bathonian–Callovian times and drowning of the sandy depositional system in the Middle–Late Callovian. Six facies associations are recognised in the Pelion–Fossilbjerget couplet, representing estuarine, shoreface, offshore transition zone and offshore environments. The north–southtrendingaxis of the Jameson Land Basin had a low inclination, and deposition was sensitive to even small changes in relative sea level which caused the shorelines to advance or retreat over tens to several hundreds of kilometres. Eight composite sequences, termed P1–P8, are recognised and are subdivided into a total of 28 depositional sequences. The duration of the two orders of sequences was about 1–2 Ma and 360,000 years, respectively. The Upper Bajocian P1–2 sequencesinclude the most basinally positioned shallow marine sandstones, deposited during major sealevel lowstands. The lowstands were terminated by significant marine

  16. 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

  17. Christ's thorn formation (Paliureta spina-christi in the Tbilisi environs (East Georgia, South Caucasus

    Directory of Open Access Journals (Sweden)

    N.J. Lachashvili

    2018-06-01

    Full Text Available Christ's thorn formation (Paliureta spina-christi of Tbilisi environs is studied. This formation is one of the typical representatives of hemixerophilous shrubberies of shibliak type in the Caucasus region and one of the characteristic for vegetation cover of Tbilisi surroundings. Plant communities of Christ's thorn formation with different plots area are fragmentary spread almost all over the territory of Tbilisi environs from 400 to 800 (900 m above s.l.. Plant communities are developed on slopes and plane place with various exposure and inclination, mainly on the grey-cinnamonic and cinnamonic soils. The most xerophilous variants are developed on the erosive bare mother rocks as well. In Tbilisi environs the Christ-thorn's plant communities are either primary or secondary origin. Formation is characterized by rich typological and floristic composition. We identified 6 plant communities: (1 Paliureto-mixtofruticetum gramino-mixtoherbosum, (2 Paliureto-Rhmanetum gramino-mixtoherbosum, (3 Paliureto gramino-mixtoherbosum, (4 Paliureto bothriochlooso gramino-mixtoherbosum, (5 Paliuretum festuceto-bothriochloosum, (6 Paliureto-Astragaleto-Rhamnetum. For each separated plant communities the basic structural characteristics (general projective coverage, projective coverage, distribution and height of layers, sodding degree, dominant-edificator plants, characteristic species, number of species, moss cover, litter, species richness, spectrum of life forms, distribution area in the Tbilisi environs and main physical-geographical conditions (topography, altitude, exposure, inclination, soil type are given. 190 species of vascular plants, which belong to 40 families and 132 genera, were recorded. In the floristic spectrum leading families are: 1. Poaceae – 27 species (14,2%, 2. Asteraceae – 25 species (13,2%, 3. Fabaceae – 17 species (8,9%, 4-5. Lamiaceae and Rosaceae – 15-15 species (7,9-7,9%, 6-8. Apiaceae, Caryophyllaceae and Rubiaceae – 8

  18. The Jurassic of Denmark and Greenland: Palynostratigraphy and palaeoenvironment of the Middle Jurassic Sortehat Formation (Neill Klinter Group, Jameson Land, East Greenland

    Directory of Open Access Journals (Sweden)

    Koppelhus, Eva B.

    2003-10-01

    Full Text Available The grey–black mudstones of the Sortehat Formation form part of the Middle Jurassic fill of the Jameson Land Basin in East Greenland. The formation is exposed in the southernmost part of the north–south-trending, Mesozoic rift system in East Greenland that was part of the epeiric seaway between East Greenland and Norway. Sedimentological observations of the Sortehat Formation indicate deposition in an offshore marine setting that was typically low energy and periodically oxygen-deficient but was influenced by storm currents on occasion. Detailed palynological studies of the Sortehat Formation have resulted in the definition of three palynological assemblage zones recognised at four localities, namely Enhjørningen Dal and Pelion (north Jameson Land, the type section at Sortehat (central Jameson Land and Albuen at Neill Klinter along Hurry Inlet(south-east Jameson Land. In stratigraphic order, these zones are termed the Botryococcus Assemblage Zone, the Nannoceratopsis gracilis – Nannoceratopsis senex Assemblage Zone, and the Sentusidinium pelionense Assemblage Zone. They are recognised on the basis of the identification of approximately 110 species of palynomorphs, including 45 species of spores, 30 of pollen, 22 of dinoflagellate cysts, 10 acritarch species, two species of algae, and some fungal spores. An Aalenian – ?Early Bajocian age is suggested for the Sortehat Formation on the basis of thepalynoflora.Interpretation of the palynomorph assemblages suggests that the formation accumulated in a shallow, brackish marine environment. A significant terrestrial input, including the freshwater greenalga Botryococcus, is recorded in the lower part of the formation and interpreted as an allochthonous accumulation in an offshore marine environment related to transgression of a low-lyingcoastal plain. A marked shift in the palynomorph assemblage seen by diversification of marine microplankton above the base of the formation, indicates an

  19. Regions of open water and melting sea ice drive new particle formation in North East Greenland.

    Science.gov (United States)

    Dall Osto, M; Geels, C; Beddows, D C S; Boertmann, D; Lange, R; Nøjgaard, J K; Harrison, Roy M; Simo, R; Skov, H; Massling, A

    2018-04-17

    Atmospheric new particle formation (NPF) and growth significantly influences the indirect aerosol-cloud effect within the polar climate system. In this work, the aerosol population is categorised via cluster analysis of aerosol number size distributions (9-915 nm, 65 bins) taken at Villum Research Station, Station Nord (VRS) in North Greenland during a 7 year record (2010-2016). Data are clustered at daily averaged resolution; in total, we classified six categories, five of which clearly describe the ultrafine aerosol population, one of which is linked to nucleation events (up to 39% during summer). Air mass trajectory analyses tie these frequent nucleation events to biogenic precursors released by open water and melting sea ice regions. NPF events in the studied regions seem not to be related to bird colonies from coastal zones. Our results show a negative correlation (r = -0.89) between NPF events and sea ice extent, suggesting the impact of ultrafine Arctic aerosols is likely to increase in the future, given the likely increased sea ice melting. Understanding the composition and the sources of Arctic aerosols requires further integrated studies with joint multi-component ocean-atmosphere observation and modelling.

  20. Education and Training for Development in East Asia: The Political Economy of Skill Formation in East Asian Newly Industrialised Economies. ESRC Pacific Asia Programme [Series].

    Science.gov (United States)

    Ashton, David; Green, Francis; James, Donna; Sung, Johnny

    This book provides a detailed analysis of the development of education and training systems in Asia and the relationship with the process of economic growth. Focus is on four impoverished agrarian economies--Hong Kong, Singapore, South Korea, and Taiwan--that were transformed in little more than a generation into East Asian "tigers":…

  1. The Silurian Hoedongri Formation in the Taebaeksan Basin of Korea Revisited: its Significance in the Tectonic Reconstruction of East Asia

    Science.gov (United States)

    Chae, S.; Hong, J.; Jung, S.; Ree, J.

    2011-12-01

    The Silurian Hoedongri Formation of the Taebaeksan Basin of South Korea has been used as a key unit to the correlation of tectonic provinces of East Asia since the South China craton (or Yangtz block) contains Silurian-Devonian sequences as well as Cambrian-Ordovician ones in the Paleozoic basins while the North China craton (or Sino-Korea block) is devoid of Silurian-Devonian sequences. In the Biryongdong area near the type locality of the Hoedongri Formation, it has been reported that the gray limestone of the Hoedongri Formation unconformably overlies brownish gray limestone of the Ordovician Haengmae Formation. However, our detailed examination on the Biryongdong section reveals that both of the brownish gray and gray limestones are mylonitic marbles with the boundary between the two units being a healed fault breccia zone (~ 12 m thick). The main difference of the two units is that repeated cycles of plastic deformation and fracturing occurred in the underlying brownish gray marble ('Haengmae') while the gray marble ('Hoedongri') deformed mainly by intracrystalline plasticity. The mylonitic foliation strikes NW with a low to moderate dip angle (20-60°) to NE. The ridge-in-groove type lineation on foliation surface trends NNW. The shape-preferred foliation of elongated calcite grains are oblique to the mylonitic foliation defined by layers with a grain-size variation, indicating a top-to-the-SSE shear sense. The mylonitic marble consists of elongated remnant grains (80-120 μm) with deformation twins and dynamically recrystallized matrix grains (10-40 μm). Grain boundaries and twin boundaries are lobate or wavy, indicating dynamic boundary migration. Some layers of the gray mylonitic marble are composed entirely of larger (80-120 μm) elongated calcite grains. In the brownish gray mylonitic marble unit, layers of brittle fracturing overprinting mylonitic foliation occur. In some of these layers, fragments (several cm - tens of cm) of the mylonitic marble are

  2. Disentangling Diagenesis From the Rock Record: An Example From the Permo-Triassic Wordie Creek Formation, East Greenland

    Science.gov (United States)

    Roberts, J.; Turchyn, A. V.; Wignall, P. B.; Newton, R. J.; Vane, C. H.

    2018-01-01

    The measurement of isotope ratios in sedimentary rocks deposited over geological time can provide key insights to past environmental change over important intervals in the past. However, it is important to be aware that secondary alteration can overprint the original isotopic records. We demonstrate this principle using high-resolution carbon, sulfur, and oxygen isotope measurements in organic carbon, pyrite, and carbonate minerals (δ13Corg, δ34Spyr, δ34SCAS, δ13Ccarb, and δ18Ocarb) and kerogen analyses (HI and OI) from the Wordie Creek Formation, East Greenland. These sediments were initially deposited across the Permo-Triassic transition, but as we will show, the carbonate record has been altered by interaction with meteoric water significantly after initial deposition. Comparison of the better preserved organic carbon and pyrite records with a proximal Permo-Triassic sequence reveals significant pyrite-sulfur isotope variability across the Permo-Triassic transition. This regional heterogeneity argues against basin-wide euxinia and instead suggests localized changes in sulfur fractionation in response to variations in organic carbon flux. This hypothesis can be used to explain seemingly inconsistent regional trends in other sulfur isotopes across the Permo-Triassic transition.

  3. Rare Earths in fluorite deposits of Elika Formation (East of Mazandaran Province

    Directory of Open Access Journals (Sweden)

    Zahra Mehraban

    2016-07-01

    Full Text Available Introduction The Central Alborz in eastern Mazandaran province is host to the most important carbonate-hosted fluorite deposits in Iran, such as Pachi-Miana, Sheshroodbar, Era and Kamarposht. In these deposits, mineralization occurs in the upper parts of the middle Triassic Elika formation (Vahabzadeh et al., 2009 and references therein. These deposits have long been studied, and various models are presented for ore genesis. Nevertheless, ore genesis in these deposits is still unclear. The present study of the geochemistry of the REEs of these deposits is intended to improve genetic models. Materials and methods Three hundred samples were taken from above mentioned deposits. Samples were categorized into 5 groups: (1 fluorite ore types, (2 ore-stage calcite, (3 carbonate host rocks, (4 basaltic rock around the deposits, and (5 shale of the Shemshak formation. Fourteen pure fluorite samples, 4 samples of pure calcite, 4 samples of carbonate host rock, 1 sample of basalt and 1 sample of shale were analyzed for REEs by ICP-MS at West Lab in Australia. Results Analytical data on fluorite from the Elika deposits show very low REE concentrations (0.5-18ppm, in calcite(0.5-3ppm in carbonate host rocks – limestone (1.8-7ppm, and in dolomitic limestone 6.5ppm, compared with upper Triassic basalt (43ppm and shale (261ppm. REE in fluorite of these deposits are strongly enriched (10 3 to 10 6 times relative to normal sea water, ore stage calcite and carbonate host rocks, especially for mid-REEs (Eu, Gd and heavy REEs (Lu, Yb, La/Yb=~0.05. Also, LREEs depletion (La/Sm= 2-10 and HREEs (La/Yb=0.01-0.08 relatively enrichment of fluorites compared with limestone (La/Sm=2.5-4, La/Yb=0.1-1.5 and dolomitic limestone (La/Sm=4.28, La/Yb=0.07-0.4 host rocks as well as positive Eu anomaly are the most important REEs signatures in fluorites. Fluorite elsewhere in the world with low total REE conten thas been interpreted to have a sedimentary origin (Ronchi et al

  4. New Prespective Paleogeography of East Java Basin; Implicationrespond to Oil and Gas Eksploration at Kujung Formation Carbonate Reservoar

    Science.gov (United States)

    Aprilana, C.; Premonowati; S, Hanif I.; Choirotunnisa; Shirly, A.; Utama, M. K.; Sinulingga, Y. R.; Syafitra, F.

    2018-03-01

    Paleogeography is one of critical points that always less considered by explorationist in the world. Almost all of the consideration is focused on trapping mechanism. Paleogeography is guidance in understanding both of physical and chemical of rock characteristic which will correlate with its depositional environment. Integration of various geological and geophysical data such as; tectonic, structural geology, stratigraphy, lithology, and biostratigraphy will lead us to a better understanding of rock characteristics. Six paleogeographic interpretations was made consist of; Early Tertiary (P5-56-55 ma), Middle Eocene (P14-41 ma), Late Oiligocene (P22-25.5 ma), Early Miocene (N7-16.5 ma), Middle Miocene (N9-14.5 ma), and Pleistocene (NN19-1.5 ma). That six paleogeographic interpretations are assumed represent the paleogeographic evolution of East Java Basin time after time. In Middle Eocene time, it would be more than hundred possibilities regarding the location where the formation deposited. This would be controlled by the existence of some local structural paleohighs and horsts which oriented NW-SE followed by their own sedimentary transportation path. With assumption that hydrocarbon generation was occurred in 15 Ma and the depth of maturation window lies on about 2,500 m depth. Therefore, the possibility of source rock maturation is high, due to almost of the clastics sediment of Ngimbang deposited into the series of grabens. The Kujung reef types simplified defines and categorize into; 1) Patch Reef 2) Berrier Reef 3) Pinnacle Reef Over Isolated Reef. Kujung Carbonates were deposited in Early Miocene when regional transgression occurred. The depositional environments were dominated by shallow marine littoral-sublittoral. Generally, the reservoir quality of this Kujung Carbonate shows fair to good quality, in range7-32% porosity, and 1-1400 mD permeability (internal SKK Migas data).

  5. Erratum to ``Eruption style and petrology of a new carbonatitic suite from the Mt. Vulture (Southern Italy): The Monticchio Lakes Formation'' [Journal of Volcanology and Geothermal Research 78 (1997) 251 265

    Science.gov (United States)

    Stoppa, Francesco; Principe, Claudia

    1998-01-01

    The Monticchio Lakes Formation (MLF) is a newly identified carbonatite-melilitite tuff sequence which is exposed in the southwestern sector of the Vulture volcano. It is the youngest example (ca. 0.13 m.y.) of this type of volcanism in Italy, although other carbonatites of smaller volume, but with similar characteristics, have been discovered recently. This volcanic event occurred in isolation after a 0.35 m.y. period of inactivity at Vulture. The eruption produced two maar-type vents and formed tuff aprons mainly composed of dune beds of lapilli. Depositional features suggest that a dry surge mechanism, possibly triggered by CO 2 expansion, was dominant during tuff emplacement. The MLF event involved a mixture of carbonatite and melilitite liquids which were physically separated before the eruption. Abundant mantle xenoliths are direct evidence of the deep-seated origin of the parental magma and its high velocity of propagation towards the surface. Often, these nodules form the core of lapilli composed of concentric shells of melilitite and/or porphyritic carbonatite. Coarse-ash beds alternate with lapilli beds and consist of abundant lumps and spherulae of very fine-grained calcite immersed in a welded, highly compacted carbonatite matrix. Porphyritic carbonatite shells of the lapilli and fine-grained spherulae of calcite in the tuff matrix suggest incipient crystallisation of a carbonatite liquid in subvolcanic conditions and eruption of carbonatite-spray droplets. Dark coloured juvenile fragments mainly consist of melilite, phlogopite, calcite, apatite, perovskite, and häuyne crystals in a carbonatite or melilitite matrix. The rocks have an extremely primitive, ultramafic composition with very high Mg# (> 85) and Cr and Ni content (1500 ppm). The calcite contains high SrO, BaO and REE of up to 1.5 wt.%. Similar compositions are typical of primary, magmatic carbonates which are found in both intrusive and extrusive carbonatites. The high modal Sr

  6. Chapter 5. Assessment of undiscovered conventional oil and gas resources-Lower Cretaceous Travis Peak and Hosston formations, Jurassic Smackover interior salt basins total petroleum system, in the East Texas basin and Louisiana-Mississippi salt basins provinces.

    Science.gov (United States)

    Dyman, T.S.; Condon, S.M.

    2006-01-01

    The Lower Cretaceous Travis Peak Formation of east Texas and southern Arkansas (and the correlative Hosston Formation of Louisiana and Mississippi) is a basinward-thickening wedge of terrigenous clastic sedimentary rocks that underlies the northern Gulf of Mexico Basin from east Texas across northern Louisiana to southern Mississippi. Clastic detritus was derived from two main fluvial-deltaic depocenters, one in northeastern Texas and the other extending from southeastern Mississippi northwestward into northeastern Louisiana. Across the main hydrocarbon-productive trend in east Texas and northern Louisiana, the Travis Peak and Hosston Formations are about 2,000 ft thick.

  7. A Virtual Petrological Microscope for All Apollo 11 Lunar Samples

    Science.gov (United States)

    Pillnger, C. T.; Tindle, A. G.; Kelley, S. P.; Quick, K.; Scott, P.; Gibson, E. K.; Zeigler, R. A.

    2014-01-01

    A means of viewing, over the Internet, polished thin sections of every rock in the Apollo lunar sample collections via software, duplicaing many of the functions of a petrological microscope, is described.

  8. The Lower Triassic Sorkh Shale Formation of the Tabas Block, east central Iran: Succesion of a failed-rift basin at the Paleotethys margin

    Science.gov (United States)

    Lasemi, Y.; Ghomashi, M.; Amin-Rasouli, H.; Kheradmand, A.

    2008-01-01

    The Lower Triassic Sorkh Shale Formation is a dominantly red colored marginal marine succession deposited in the north-south trending Tabas Basin of east central Iran. It is correlated with the unconformity-bounded lower limestone member of the Elika Formation of the Alborz Mountains of northern Iran. The Sorkh Shale is bounded by the pre-Triassic and post-Lower Triassic interregional unconformities and consists mainly of carbonates, sandstones, and evaporites with shale being a minor constituent. Detailed facies analysis of the Sorkh Shale Formation resulted in recognition of several genetically linked peritidal facies that are grouped into restricted subtidal, carbonate tidal flat, siliciclastic tidal flat, coastal plain and continental evaporite facies associations. These were deposited in a low energy, storm-dominated inner-ramp setting with a very gentle slope that fringed the Tabas Block of east central Iran and passed northward (present-day coordinates) into deeper water facies of the Paleotethys passive margin of northern Cimmerian Continent. Numerous carbonate storm beds containing well-rounded intraclasts, ooids and bioclasts of mixed fauna are present in the Sorkh Shale Formation of the northern Tabas Basin. The constituents of the storm beds are absent in the fair weather peritidal facies of the Sorkh Shale Formation, but are present throughout the lower limestone member of the Elika Formation. The Tabas Block, a part of the Cimmerian continent in east central Iran, is a rift basin that developed during Early Ordovician-Silurian Paleotethys rifting. Facies and sequence stratigraphic analyses of the Sorkh Shale Formation has revealed additional evidence supporting the Tabas Block as a failed rift basin related to the Paleotethys passive margin. Absence of constituents of the storm beds in the fair weather peritidal facies of the Sorkh Shale Formation, presence of the constituents of the storm beds in the fair weather facies of the Elika Formation (the

  9. Petrology and radiogeology of the Stripa pluton

    International Nuclear Information System (INIS)

    Wollenberg, Harold; Flexser, Steve; Andersson, Lennart

    1980-01-01

    To better define the character of the rock encompassing the thermomechanical and hydrological experiments at the Stripa mine in central Sweden, and to help determine the size of the Stripa pluton, detailed studies were conducted of the petrology and radiogeology of the quartz monzonite and adjacent rocks. Petrologic studies emphasized optical petrography, with supplementary X-ray diffraction, X-ray fluorescence and microprobe analyses. Radiogeologic investigations were based primarily on surface and underground gamma-ray spectrometric measurements of uranium, thorium and potassium, supplemented by laboratory gamma spectrometric analyses and fission-track radiographic determinations of the locations and abundance of uranium in the rock matrix. Both the quartz monzonite and the metavolcanic leptite which it intruded are strongly fractured. Two stages of fracture filling are evident; an earlier stage encompassing quartz, sericite, feldspar, epidote, and chlorite, and a later stage dominated by carbonate minerals. The Stripa quartz monzonite is chemically and mineralogically distinct from other plutons in the region. Muscovite is the predominant mica in the quartz monzonite; biotite has been altered to chlorite, hornblende is absent, and accessory minerals are scarce. In contrast, in other plutons in the Stripa region biotite and hornblende are prominent mafic minerals and accessory minerals are abundant. The Stripa quartz monzonite is also considerably more radioactive than the leptite and other plutons in the region. Uranium and thorium abundances are both- 30 ppm, considerably higher than in 'normal' granitic rocks where the thorium-to-uranium ratio generally exceeds 2. Potassium-argon dating of muscovite from the Stripa quartz monzonite indicates that this rock may be older, at 1691 million years than granitic rock of the neighboring Gusselby and Kloten massifs, whose ages, based on K-Ar dating of biotite, are respectively 1604 and 1640 m.y. Heat flow and heat

  10. Petrology and radiogeology of the Stripa pluton

    Energy Technology Data Exchange (ETDEWEB)

    Wollenberg, Harold; Flexser, Steve; Andersson, Lennart

    1980-12-01

    To better define the character of the rock encompassing the thermomechanical and hydrological experiments at the Stripa mine in central Sweden, and to help determine the size of the Stripa pluton, detailed studies were conducted of the petrology and radiogeology of the quartz monzonite and adjacent rocks. Petrologic studies emphasized optical petrography, with supplementary X-ray diffraction, X-ray fluorescence and microprobe analyses. Radiogeologic investigations were based primarily on surface and underground gamma-ray spectrometric measurements of uranium, thorium and potassium, supplemented by laboratory gamma spectrometric analyses and fission-track radiographic determinations of the locations and abundance of uranium in the rock matrix. Both the quartz monzonite and the metavolcanic leptite which it intruded are strongly fractured. Two stages of fracture filling are evident; an earlier stage encompassing quartz, sericite, feldspar, epidote, and chlorite, and a later stage dominated by carbonate minerals. The Stripa quartz monzonite is chemically and mineralogically distinct from other plutons in the region. Muscovite is the predominant mica in the quartz monzonite; biotite has been altered to chlorite, hornblende is absent, and accessory minerals are scarce. In contrast, in other plutons in the Stripa region biotite and hornblende are prominent mafic minerals and accessory minerals are abundant. The Stripa quartz monzonite is also considerably more radioactive than the leptite and other plutons in the region. Uranium and thorium abundances are both- 30 ppm, considerably higher than in "normal" granitic rocks where the thorium-to-uranium ratio generally exceeds 2. Potassium-argon dating of muscovite from the Stripa quartz monzonite indicates that this rock may be older, at 1691 million years than granitic rock of the neighboring Gusselby and Kloten massifs, whose ages, based on K-Ar dating of biotite, are respectively 1604 and 1640 m.y. Heat flow and heat

  11. Sedimentology of the Teekloof formation to the east of Aberdeen (C.P.) with reference to uranium mineralization

    International Nuclear Information System (INIS)

    Simmonds, A.L.E.

    1982-01-01

    An area to the immediate east of Aberdeen (C.P.), banded in the north by the Rooiberge and to the east by the Sundays River, has been sedimentologically studied. A notable feature of the sediments investigated, is the presence of linear zones of increased sandstone. Some of the sediments also showed an exessive volume of argillaceous rocks. The sandstones cropping out in the Aberdeen District may be classified as lithic arkoses. Due to the manner in which the detrital grains appear to 'float' in calcite, an expansive growth mechanism is envisaged. This implies early crystallization of calcite, and emplacement of uranium

  12. Petrology and Geochemistry of Unbrecciated Harzburgitic Diogenite MIL 07001: A Window Into Vestan Geological Evolution

    Science.gov (United States)

    Mittlefehldt, D. W.; Peng, Z. X.; Mertzman, S. A.; Mertzman, K. R.

    2014-01-01

    There is a strong case that asteroid 4 Vesta is the parent of the howardite, eucrite and diogenite (HED) meteorites. Models developed for the geological evolution of Vesta can satisfy the compositions of basaltic eucrites that dominate in the upper crust. The bulk compositional characteristics of diogenites - cumulate harzburgites and orthopyroxenites from the lower crust - do not fit into global magma ocean models that can describe the compositions of basaltic and cumulate eucrites. Recent more detailed formation models do make provision for a more complicated origin for diogenites, but this model has yet to be completely vetted. Compositional studies of bulk samples has led to the hypothesis that many diogenites were formed late by interaction of their parent melts with a eucritic crust, but those observations may alternatively be explained by subsolidus equilibration of trace elements between orthopyroxene and plagioclase and Ca-phosphate in the rocks. Differences in radiogenic Mg-26 content between diogenites and eucrites favors early formation of the former, not later formation. Understanding the origin of diogenites is crucial for understanding the petrologic evolution of Vesta. We have been doing coordinated studies of a suite of diogenites including petrologic investigations, bulk rock major and trace element studies, and in situ trace element analyses of orthopyroxene. Here we will focus on an especially unusual, and potentially key, diogenite, MIL 07001.

  13. Petrology and geochemistry of the Miocene-Pliocene fluvial succession, Katawaz Basin, Western Pakistan: Implications on provenance and source area weathering

    DEFF Research Database (Denmark)

    Kasi, Aimal K.; Kassi, Aktar Muhammad; Friis, Henrik

    Petrology and geochemistry of sandstones and mudstones of the Miocene Dasht Murgha Group (DMG) and Pliocene Malthanai Formation (MF) of the Pishin Belt (Katawaz Basin), northwestern Pakistan have been carried out to find out their provenance and source area weathering. Sandstones of the Dasht...

  14. Policy in the Area of Wages and Its Implementation in the Far East in the 1930s as a Mechanism for the Formation of Social Hierarchy

    Directory of Open Access Journals (Sweden)

    Olga I. Shestak

    2015-06-01

    Full Text Available This article, based on documents from state archives, examines Soviet policy in the area of wages through the example of the Far East. The author comes to the conclusion that the wages policy implemented in the USSR in the 1930s was a key mechanism in the formation of a hierarchical social production-type establishment. It would determine the prestige of professions and the functionality of spheres of work activity and underscored the commanding positioning of social groups, thereby setting and ensuring all key criteria for constructing a system of social inequality, on the one hand, and fixing the population to remote and scarcely populated territories, on the other.

  15. Additional results on palaeomagnetic stratigraphy of the Koobi Fora Formation, east of Lake Turkana (Lake Rudolf), Kenya

    Science.gov (United States)

    Hillhouse, J.W.; Ndombi, J.W.M.; Cox, A.; Brock, A.

    1977-01-01

    The magnetostratigraphy of the hominid-bearing sediments exposed east of Lake Turkana has been strengthened by new palaeomagnetic results. Ages obtained from several tuffs by the 40Ar/39Ar method suggest an approxmate match between the observed magnetozones and the geomagnetic polarity time scale; however, the palaeomagnetic results are also compatible with a younger chronology suggested by conventional K-Ar dating of the KBS Tuff. ?? 1977 Nature Publishing Group.

  16. Petrology of basalts from Loihi Seamount, Hawaii

    Science.gov (United States)

    Hawkins, James; Melchior, John

    1983-12-01

    Loihi Seamount is the southeasternmost active volcano of the Emperor-Hawaii linear volcanic chain. It comprises a spectrum of basalt compositional varieties including basanite, alkali basalt, transitional basalt and tholeiite. Samples from four dredge collections made on Scripps Institution of Oceanography Benthic Expedition in October 1982 are tholeiite. The samples include highly vesicular, olivine-rich basalt and dense glass-rich pillow fragments containing olivine and augite phenocrysts. Both quartz-normative and olivine-normative tholeiites are present. Minor and trace element data indicate relatively high abundances of low partition coefficient elements (e.g., Ti, K, P. Rb, Ba, Zr) and suggest that the samples were derived by relatively small to moderate extent of partial melting, of an undepleted mantle source. Olivine composition, MgO, Cr and Ni abundances, and Mg/(Mg+Fe), are typical of moderately fractionated to relatively unfractionated "primary" magmas. The variations in chemistry between samples cannot be adequately explained by low-pressure fractional crystallization but can be satisfied by minor variations in extent of melting if a homogeneous source is postulated. Alternatively, a heterogeneous source with variable abundances of certain trace elements, or mixing of liquids, may have been involved. Data for 3He/ 4He, presented in a separate paper, implies a mantle plume origin for the helium composition of the Loihi samples. There is little variation in the helium isotope ratio for samples having different compositions and textures. The helium data are not distinctive enough to unequivocally separate the magma sources for the tholeiitic rocks from the other rock types such as Loihi alkalic basalts and the whole source region for Loihi may have a nearly uniform helium compositions even though other element abundances may be variable. Complex petrologic processes including variable melting, fractional crystallization and magma mixing may have blurred

  17. Organic petrology in the service of archaeology

    Energy Technology Data Exchange (ETDEWEB)

    Teichmueller, M.

    1992-02-01

    The techniques of organic petrology have been used to study the nature and provenance of 81 ornaments ranging in age from the Celtic (dated as late Hallstatt-early La Tene times, 500-300 B.C.) to Roman (1st-4th Century A.D.) periods, which have been recovered from graves and settlements in Germany and Switzerland. The ornaments were mainly black or dark brown armlets but also included beads, buttons and medallions. The most commonly used source material was jet (22 objects) which is derived from bituminized drift woods found in Liassic oil shale, probably mainly of English provenance. Eleven objects were made from Carboniferous cannel coal and four from boghead coal, both of unknown geographic provenance. Only one object proved to be made from {ital Posidonia} shale, a liassic oil shale from southern Germany. The identification of two distinctive sapropelites, used mainly for the production of armlets, is of particular interest. These sapropelites are the 'Schwarte' from the top of the Kounova Seam (Stephanian) of northern Bohemia (15 objects) and the Kimmeridge 'coal' of Dorset, England (19 objects). The recognition of these organic materials was made possible by the study of fresh rock samples. All the armlets made from 'Schwarte' were excavated in the Celtic oppidum at Manching in southern Germany; the armlets made from Kimmeridge 'coal' were found in Celtic and Roman graves. These discoveries suggest the existence of early trade routes crossing the English Channel and passing south to Switzerland, probably along the River Rhine. A very few armlets were made from dark tuff (probably of Bohemian origin), black glass or dark brown bone. These materials were probably all used as substitutes for jet and/or sapropelites. It is interesting to note that all these dark armlets were thought to possess magic properties, which may explain their frequency. 26 refs., 4 figs., 4 tabs.

  18. A new tephrochronology for early diverse stone tool technologies and long-distance raw material transport in the Middle to Late Pleistocene Kapthurin Formation, East Africa.

    Science.gov (United States)

    Blegen, Nick; Jicha, Brian R; McBrearty, Sally

    2018-05-09

    The Middle to Late Pleistocene (780-10 ka) of East Africa records evidence of significant behavioral change, early fossils of Homo sapiens, and the dispersals of our species across and out of Africa. Studying human evolution in this time period thus requires an extensive and precise chronology relating behavioral evidence from archaeological sequences to aspects of hominin biology and evidence of past environments from fossils and geological sequences. Tephrochronology provides the chronostratigraphic resolution to achieve this through correlation and dating of volcanic ashes. The tephrochronology of the Kapthurin Formation presented here, based on tephra correlations and 40 Ar/ 39 Ar dates, provides new ages between 395.6 ± 3.5 ka and 465.3 ± 1.0 ka for nine sites showing diverse blade and Levallois methods of core reduction. These are >110 kyr older than previously known in East Africa. New 40 Ar/ 39 Ar dates provide a refined age of 222.5 ± 0.6 ka for early evidence of long-distance (166 km) obsidian transport at the Sibilo School Road Site. A tephra correlation between the Baringo and Victoria basins also provides a new date of ∼100 ka for the Middle Stone Age site of Keraswanin. By providing new and older dates for 11 sites containing several important aspects of hominin behavior and extending the chronology of the Kapthurin Formation forward by ∼130,000 years, the tephrochronology presented here contributes one of the longest and most refined chronostratigraphic frameworks of Middle through Late Pleistocene East Africa. This tephrochronology thus provides the foundation to understand the process of modern human behavioral evolution as it relates to biological and paleoenvironmental circumstances. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. A New Tephrochronology for Early Diverse Stone Tool Technologies and Long-Distance Raw Material Transport in the Middle-Late Pleistocene Kapthurin Formation, East Africa.

    Science.gov (United States)

    Blegen, N.; Jicha, B.

    2017-12-01

    The Middle to Late Pleistocene (780-10 ka) of East Africa records significant behavioral change, the earliest fossils of Homo sapiens and the dispersals of our species across and out of Africa. Studying human evolution in the Middle to Late Pleistocene thus requires an extensive and precise chronology relating the appearances of various behaviors preserved in archaeological sequences to aspects of hominin biology and evidence of past environments preserved in the fossils and geological sequences. Tephrochronology provides the chronostratigraphic resolution to achieve this through correlation and dating of volcanic ashes. The tephrochronology of the Kapthurin Formation presented here, based on tephra correlations and 40Ar/ 39Ar dates, provides new ages between 396.3 ± 3.4 ka and 465.3 ± 1.0 ka for nine sites showing some of the earliest evidence of diverse blade and Levallois methods of core reduction. These are >110 kyr older than previously known in East Africa. New 40Ar/ 39Ar dates provide a refined age of 222.5 ± 0.6 ka for early evidence of long-distance obsidian transport at the Sibilo School Road Site. Long-distance tephra correlation between the Baringo and Lake Victoria basins also provides a new date of 100 ka for the Middle Stone Age site of Keraswanin. By providing new or older dates for 11 sites containing several important aspects of hominin behavior and extending the chronology of the Kapthurin Formation forward by 130,000 years, the tephrochronology presented here contributes one of the longest and most refined chronostratigraphic frameworks relevant to modern human evolution. In conjunction with recent archaeological and paleoenvironmental data, this tephrochronology provides the foundation to understand the process of modern human behavioral evolution through the East African Middle and Late Pleistocene as it relates to biological and paleoenvironmental circumstances.

  20. Review of the petrology of the Auckland Volcanic Field

    International Nuclear Information System (INIS)

    Smith, I.E.M.; McGee, L.E.; Lindsay, J.M.

    2009-01-01

    Research has long shown that the petrology of suites of volcanic rock can be used to define and understand the fundamental parameters of the magmatic systems that feed volcanoes. The geochemistry of volcanic rocks provides information about the nature of the source rocks, depths and amounts of melting, the processes that act on magmas as they rise to the surface and, most importantly, the rates of these processes. In turn, the answers to fundamental petrological questions can provide input to important questions concerning volcano hazard scenarios and hazard mitigation challenges. The multi-disciplinary DEVORA research programme, launched in 2008, is a GNS Science-University of Auckland collaboration with the aim of DEtermining VOlcanic Risk in Auckland. One of its main themes is the development of an integrated geological model for the Auckland Volcanic Field (AVF) by investigating the physical controls on magma generation, ascent and eruption though detailed structural and petrological investigations. A key data set underpinning this theme is a comprehensive geochemical database for the rocks of the AVF. This report, Review of the Petrology of the Auckland Volcanic Field, is a synthesis and commentary of all petrological and geochemical data currently available for the AVF. It represents one of several reports carried out as part of the 'synthesis' phase of DEVORA, whereby existing data from previous work is collated and summarised, so that gaps in current knowledge can be appropriately addressed. In this report we utilise published and unpublished sources to summarise the petrological data available up to May 2009, and identify where new data and approaches will improve our understanding of the magmatic system which feeds the field. (author). 53 refs., 7 figs., 2 tabs.

  1. The use of petrology in Philippine geothermal system

    International Nuclear Information System (INIS)

    Reyes, A.G.

    1992-01-01

    Petrology is used in the various stages of exploration, development and exploitation of a geothermal area, often in conjunction with other fields of study. It is an effective operations tool for predicting syn- and post-drilling conditions in a well, for field and well maintenance, and to a small extent for monitoring fluids passing through the pipelines and steam turbines. Petrological data and interpretations are important in assessing an exploration area, and in formulating and developing strategy of a geothermal field. (auth.). 11 figs

  2. Meeting of Commission of International Committee on Petrology of Coals

    Energy Technology Data Exchange (ETDEWEB)

    Timofeev, P P; Bogolyubova, L I

    1982-03-01

    In Urbana, Illinois from 18-20 May 1979 the XXXII session of the International Committee on Petrology met. Reports were made on standards for the study of bituminous and anthracite coals. Use of reflective capacity of vitrain to determine coalification of coals was discussed along with a proposition to establish numerical boundaries between brown, bituminous and anthracite coals. The re-editing of the International Dictionary on Petrology of Coals was agreed upon in view of new facts on microcomponents of coal and methods of studying them. The next meeting of the Commission took place at Ostrav, Czechoslovakia from 14-26 April 1980. At the plenary session, new officials were elected and agreement to re-edit the Dictionary on Petrology of Coals was confirmed. At the meeting of the Commission on Coal Petrography the question of the determination of components of coal by quantitative diagnosis, and results of determining components of vitrain by measuring its reflective capacity were reported on. At the meeting of the Committee on Applying Facts of Petrology in Geology, the classification of solid oil bitumen and organic substance of sediments was discussed. At the meeting of the Committee on the Application of the Petrology of Coals in Industry, attention was given to discussing basic parameters for the international classification of coals to be presented at the meeting of the Economic Commission of Europe in Geneva. In the final plenary session of the commission, results of discussions were summarized. The next session was to be held in France in 1981. (In Russian)

  3. Weathering of Igneous, Metamorphic, and Sedimentary Rocks in a Semi-arid Climate - An Engineering Application of Petrology

    Science.gov (United States)

    Harrison, W. J.; Wendlandt, R. F.

    2003-12-01

    Over the last 10 years, analytical methods have been introduced to students in CSM's undergraduate geological engineering program through a multi-year and multi-course approach. Beginning with principles and simple applications of XRD and SEM in sophomore Mineralogy and building on these skills in subsequent junior and senior year courses, geological engineers acquire proficiency in analytical methods. Essential workplace skills are thus acquired without adding an extra course in the undergraduate program. The following exercise is completed by juniors in an integrated Ig.-Met.-Sed. petrology course. The identification of clay mineral assemblages in soils provides a unique opportunity to demonstrate how basic principles of petrology and geochemistry are applied to engineering design criteria in construction site preparation. Specifically, the problem investigates the conditions leading to the formation of smectite in soils and the resulting construction risk due to soil expansion. Students examine soils developed on igneous, metamorphic, and sedimentary rocks near Denver, Colorado. The field locations are areas of suburban growth and several have expansive soil problems. The 2-week exercise includes sample collection, description, and preparation, determining clay mineralogy by XRD, and measurement of Atterberg Plasticity Indices. Teaching materials may be found at: http://serc.carleton.edu/NAGTWorkshops/petrology03/. This exercise accomplishes three objectives: First, skills in XRD analysis are developed by introducing students to concepts of particle size separation, particle orientation, and sequential analysis steps which are standard practices in clay characterization. Second, lecture material on the geochemistry of weathering of different rock types is reinforced. Students interpret the origin of clay mineral assemblages developed in soils derived from Precambrian gneisses, lower Paleozoic feldspathic sandstones, upper Paleozoic marine shales, and Tertiary

  4. Organophosphate esters in East Greenland polar bears and ringed seals: Adipose tissue concentrations and in vitro depletion and metabolite formation.

    Science.gov (United States)

    Strobel, Adelle; Willmore, William G; Sonne, Christian; Dietz, Rune; Letcher, Robert J

    2018-04-01

    East Greenland is a contamination "hot spot" for long-range transported anthropogenic chemicals, including organophosphate esters (OPEs). High concentrations of OPEs have been reported in arctic air while very little is known for wildlife where OPE tissue residues levels appear to be strongly influenced by biotransformation. In the present study, the hepatic in vitro metabolism of six environmentally relevant organophosphate (OP) triesters and corresponding OP diester formation were investigated in East Greenland polar bears (PBs) and ringed seals (RSs). The in vitro metabolism assay results were compared to adipose levels in field samples from the same individuals. In vitro OP triester metabolism was generally rapid and structure-dependent, where PBs metabolized OPEs more rapidly than RSs. Exceptions were the lack of triethyl phosphate (TEP) metabolism and slow metabolism of tris(2-ethylhexyl) phosphate (TEHP) in both species. OP diester metabolites were also formed with the exception of TEP which was not metabolized at all. Tris(1,3-dichloro-2-propyl) phosphate was completely converted to its corresponding diester. However, the mass balances showed that OP diester formation corresponding to TEHP, tri(n-butyl) phosphate, and tris(2-butyoxyethyl) phosphate did not account for 100% of the OP triester depletion, which indicated alternate pathways of OP triester metabolism had occurred. Triphenyl phosphate was completely converted to its OP diester metabolite in PBs but not in RSs suggesting species-specific differences. The results demonstrated that OP triester bioaccumulation and fate in PBs versus their RS prey is substantially influenced by biotransformation. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Magmatic plumbing system of Kilauea Volcano: Insights from Petrologic and Geochemical Monitoring

    Science.gov (United States)

    Garcia, M. O.; Pietruszka, A. J.; Marske, J.; Greene, A.; Lynn, K. J.

    2016-12-01

    Monitoring the petrology and geochemistry of lavas from active volcanoes in near realtime affords the opportunity to formulate and evaluate models for magma transport, mixing, and storage to help predict eruption scenarios with greater confidence and better understand magmatic plumbing systems (e.g., Poland et al. 2012, Nat. Geosci. 5, 295-300). Continous petrologic and geochemical monitoring of two ongoing eruptions at the summit and east rift zone of Kilauea Volcano on the Island of Hawaii have revealed much about the dynamics of magmatic processes. When the composition of lava shifted to a more MgO-rich composition in April 1983, we predicted that the Puu Oo eruption would not be short-lived. We had no idea it would continue for over 33 years. Subsequent changes in lava composition have highlighted the interplay between mixing pockets of rift-zone stored magma with new mantle-derived magma and the cooling-induced crystal fractionation during brief (usually days) eruption hiatuses. Surprisingly, the mantle derived magma has continued to change in composition including several 10-year cycles in Pb isotope ratios superimposed on a progressive depletion in highly incompatible elements (Greene et al. 2013, G3, doi: 10.1002/ggge.20285). These compositional trends are contrary to those observed for sustained basaltic eruptions on continents and argue for melt extraction from a multi-component source with 1-3 km wide heterogeneities. Compositional zoning within olivine phenocrysts, created by diffusive re-equilibration, also provide insights into magma mixing, storage, and transport at Kilauea. Timescales modeling of Fe-Mg and Ni concentration gradients within Puu Oo olivine indicate that crystals can be stored at magmatic temperatures for months to a few years before eruption (Shea et al. 2015, Geology 43, 935-938). Kilauea's ongoing eruptions continue to provide a dynamic laboratory for positing and testing models for the generation and evolution of basaltic magma.

  6. Depositional History and Sequence Stratigraphy of the Middle Ordovician Yeongheung Formation (Yeongweol Group), Taebaeksan Basin, mid-east Korea

    Science.gov (United States)

    Kwon, Yoo Jin; Kwon, Yi Kyun

    2017-04-01

    The Middle Ordovician Yeongheung Formation consists of numerous meter-scale, shallowing-upward cycles which were deposited on a shallow-marine carbonate platform. Many diagnostic sedimentary textures and structures such as supratidal laminite, tepee structure, and solution-collapsed breccia are observed, which enable to infer the dry climate and high salinity conditions during deposition of the formation. In order to understand its depositional history, this study focuses on vertical and spatial stacking patterns of the second- to third-order sequences through the detailed outcrop description and geologic mapping. A total 19 lithofacies have been recognized, which can be grouped into 5 facies associations (FAs): FA1 (Supratidal flat), FA2 (Supratidal or dolomitization of peritidal facies), FA3 (Intertidal flat), FA4 (Shallow subtidal to peritidal platform), FA5 (Shallow subtidal shoal). Global mega-sequence boundary (Sauk-Tippecanoe) occurs in solution-collapsed breccia zone in the lower part of the formation. Correlation of the shallowing-upward cycle stacking pattern across the study area defines 6 transgressive-regressive depositional sequences. Each depositional sequences comprises a package of vertical and spatial staking of shallow subtidal cycles in the lower part and peritidal cycles in the upper part of the formation. According to sequence stratigraphic interpretation, the reconstructed relative sea-level curve of the Yeongweol platform is very similar to that of the Taebaek platform. Based on the absence of siliciclastic sequence such as the Jigunsan Formation and the lithologic & stratigraphic differences, however, the Yeongweol and Taebaek groups might not belong to a single depositional system within the North China platform. The Yeongweol Group can be divided by the four subunits into their unique lithologic successions and geographic distributions. The Eastern subunit of the Yeongweol Group is composed dominantly of carbonate rocks with a high

  7. Source rock formation evaluation using TOC & Ro log model based on well-log data procesing: study case of Ngimbang formation, North East Java basin

    Directory of Open Access Journals (Sweden)

    Fatahillah Yosar

    2017-01-01

    Full Text Available Ngimbang Formation is known as one major source of hydrocarbon supply in the North Eastern Java Basin. Aged Mid-Eocene, Ngimbang is dominated by sedimentary clastic rocks mostly shale, shaly sandstone, and thick layers of limestone (CD Limestone, with thin layers of coal. Although, laboratory analyses show the Ngimbang Formation to be a relatively rich source-rocks, such data are typically too limited to regionally quantify the distribution of organic matter. To adequately sample the formation both horizontally and vertically on a basin–wide scale, large number of costly and time consuming laboratory analyses would be required. Such analyses are prone to errors from a number of sources, and core data are frequently not available at key locations. In this paper, the authors established four TOC (Total Organic Carbon Content logging calculation models; Passey, Schmoker-Hester, Meyer-Nederloff, and Decker/Density Model by considering the geology of Ngimbang. Well data along with its available core data was used to determine the most suitable model to be applied in the well AFA-1, as well as to compare the accuracy of these TOC model values. The result shows good correlation using Decker (TOC Model and Mallick-Raju (Ro- Vitrinite Reflectance Model. Two source rocks potential zones were detected by these log models.

  8. The Tunas Formation (Permian) in the Sierras Australes foldbelt, east central Argentina: evidence for syntectonic sedimentation in a foreland basin

    Science.gov (United States)

    Lopez-Gamundi, O. R.; Conaghan, P. J.; Rossello, E. A.; Cobbold, P. R.

    1995-04-01

    The Tunas Formation, extensively exposed in the Sierras Australes foldbelt of eastern central Argentina, completes the sedimentation of the Gondwanan (Late Carboniferous-Permian) sequence, locally known as the Pillahuincó Group. The underlying units of the Group show an integrated depositional history which can be explained in terms of glaciomarine sedimentation (Sauce Grande Formation) and postglacial transgression (Piedra Azul and Bonete Formations). This succession also has a rather uniform quartz-rich, sand-sized composition indicative of a cratonic provenance from the Tandilia Massif to the northeast. Early to Late Permian deformation folded and thrusted the southwestern basin margin (Sierras Australes) and triggered the deposition of a 1,500 m — thick, synorogenic prograding wedge, the Tunas Formation, in the adjacent foreland basin (Sauce Grande or Claromecó Basin). Sandstone detrital modes for the Tunas deposits show moderate to low contents of quartz and abundant lithics, mostly of volcanic and metasedimentary origin. Paleocurrents are consistently from the SW. Tuffs interbedded with sandstones in the upper half of Tunas Formation (Early — early Late? Permian) are interpreted as being derived from volcanic glass-rich tuffs settled in a body of water. Extensive rhyolitic ignimbrites and consanguineous airborne tuffaceous material erupted in the northern Patagonian region during that period. The age constraints and similarities in composition between these volcanics and the tuffaceous horizons present in the Sauce Grande, Parana and Karoo Basins suggest a genetic linkage between these two episodes. The intimate relationship between volcanic activity inboard of the paleo-Pacific margin, deformation in the adjacent orogenic belt and subsidence and sedimentation in the contiguous foreland basin constitutes a common motif in the Sauce Grande and Karoo Basins of southwestern Gondwana.

  9. Formation of fine crystalline dolomites in lacustrine carbonates of the Eocene Sikou Depression, Bohai Bay Basin, East China

    Directory of Open Access Journals (Sweden)

    Yong-Qiang Yang

    2016-11-01

    Full Text Available Abstract The genesis of the fine crystalline dolomites that exhibit good to excellent reservoir properties in the upper fourth member of the Eocene Shahejie Formation (Es 4 s around the Sikou Sag, Bohai Bay Basin, is uncertain. This paper investigates the formation mechanisms of this fine crystalline dolomite using XRD, SEM, thin section analysis and geochemical data. The stratigraphy of the Sikou lacustrine carbonate is dominated by the repetition of metre-scale, high-frequency deposition cycles, and the amount of dolomite within a cycle increases upward from the cycle bottom. These dolomite crystals are 2–30 μm in length, subhedral to anhedral in shape and typically replace both grains and matrix. They also occur as rim cement and have thin lamellae within ooid cortices. Textural relations indicate that the dolomite predates equant sparry calcite cement and coarse calcite cement. The Sr concentrations of dolomites range from 900 to 1200 ppm. Dolomite δ18O values (−11.3 to −8.2 ‰ PDB are depleted relative to calcite mudstone (−8.3 to −5.4 ‰ PDB that precipitated from lake water, while δ13C values (0.06–1.74 ‰ PDB are within the normal range of calcite mudstone values (−2.13 to 1.99 ‰ PDB. High 87Sr/86Sr values (0.710210–0.710844 indicate that amounts of Ca2+ and Mg2+ have been derived from the chemical weathering of Palaeozoic carbonate bedrocks. The high strontium concentration indicates that hypersaline conditions were maintained during the formation of the dolomites and that the dolomites were formed by the replacement of precursor calcite or by direct precipitation.

  10. Petrologic comparisons of Cayley and Descartes on the basis of Apollo 16 soils from stations 4 and 11

    Science.gov (United States)

    Basu, A.; Mckay, D. S.

    1984-01-01

    Petrologic aspects of the Cayley and Descartes formations are reviewed in the light of new data on Apollo 16 soils. Specific comparison of the modal abundances of lithic fragments in drive tube sample 64001/2 from the slopes of Stone Mountain (station 4) and in soil 67941 from the North Ray Crater rim (station 11) shows that melt rocks, especially poikilitic rocks, are more abundant at station 4 than at station 11; the reverse is true for fragmental breccias. Such lithologic differences suggest that stations 4 and 11 do not belong to the same geologic formation. Metamorphosed breccias are pervasive in both the formations and may represent a local component that has been reworked and diluted as fresh materials were added. Lithologic compositions inferred from the study of soil samples are different from lithologic compositions inferred from the study of rake samples or breccia clasts. This difference may be related to a mixing of material of different grain size distributions. The petrology of soils at the Apollo 16 site may not accurately reflect original material associated with either the Descartes or the Cayley formation because of extensive mixing with local material.

  11. Fission-track ages of the Tokai Group and associate formations in the east coast areas of Ise Bay and their significance in geohistory

    International Nuclear Information System (INIS)

    Makinouchi, Takeshi; Danhara, Toru; Isoda, Kunitoshi.

    1983-01-01

    Fission-track ages of volcanic ash layers within the Tokai Group and associate formations in the east coast areas of Ise Bay are obtained by grain-by-grain method with which individual ages for the respective zircon grains are measured. They are as follows; 1) a volcanic ash layer in the Karayama Formation (tentative age: 1.9 +- 0.4 Ma). Among the zircon grains in this layer, essential ones occupy only 1 per cent, and the others are accidental. 2) Ohtani volcanic ash layer (4.3 +- 0.6 Ma). 3) Kosugaya volcanic ash layer (4.0 +- 0.5 Ma). 4) Kaminoma volcanic ash layer (5.3 +- 0.4 Ma). 5) A volcanic ash layer in the Toyoura Formation seems to be older than 10 Ma. 6) Zircon grains in the Kofu volcanic ash layer (Tokai Group) include two types of spontaneous namely track, clear and vague ones. The latter vague tracks are shorter and thiner, and seem to suffer thermal annealing. The ages obtained have clarified the following Points; a) The tentative age, 1.9 Ma, of the ''Karayama'' volcanic ash layer suggests the existence of unknown Plio-Pleistocene sediment in the Nagoya area. b) The sedimentary basin of Lake Tokai was formed in the latest Miocene, about 6.5 Ma. Generation of the basin coincides approximately with the stage of synchronous and abrupt change in sedimentation rate in sedimentary basins on the Pacific side of central and southern Japan. c) The Tokai Group in Chita (Tokoname Group) intercalates the Gilbert/Epoch 5 boundary in the paleomagnetic chronology in the middle horizon of the group. d) Average rate of sedimentation is about 1 m/10 4 yrs in the marginal areas of the basin, and 3-5 m/10 4 yrs in the central areas. (author)

  12. Fifteenth annual meeting of the Society for Organic Petrology. Abstracts and program. Volume 15

    Energy Technology Data Exchange (ETDEWEB)

    Mukhopadhyay, P.K.; Avery, M.P.; Calder, J.H.; Goodarzi, F. (eds.)

    1998-01-01

    The theme of the conference was 'Sailing into the new millennium'. Abstracts of the papers are included in this volume. Topics covered included: environmental implications of fossil fuel use - geochemical and petrological perspectives; environment, coal structure, and applied coal petrology; new innovations in coal microscopy and petrology/geochemistry of coal and coke; Eastern Canadian basins with implications for hydrocarbon resources; and organic petrology/geochemistry and petroleum system - world basin perspectives. Abstracts of the poster presentations are also included. Papers will be published in an issue of the International Journal of Coal Geology.

  13. Shale gas characterization of the Dinder and Blue Nile Formations in the Blue Nile Basin, East Sudan

    Science.gov (United States)

    Shoieb, Monera Adam; Sum, Chow Weng; Bhattachary, Swapan Kumar; Abidin, Nor Syazwani Zainal; Abdelrahim, Omer Babiker

    2016-11-01

    The development of gas and oil in unconventional plays in United State and Northern Europe has affected the finances and the energy security. Geochanical properties of shale rocks can have a major impact on the efficiency of shale gas exploration. The goal of this study is to evaluate shale gas potentiality in the Blue Nile Basin, using samples from existing drilled wells. All the samples were analyzed in detail with the following organic geochemical techniques: total organic carbon (TOC), Rock-eval pyrolysis, to determine the quality and quantity of the organic matter. The total organic carbon (TOC) values for the shale intervals vary from 0.6 to 4.5weight% in FARASHA-1 Well, while in TAWAKUL-1 Well range from 0.4 to 2.4weight%, suggesting that fair to good source generative potential, as revealed by the S2 v's TOC plot. Hydrogen index (HI) values range from 12 to 182 mg HC/g TOC in the two wells, indicating type III and IV derived-input in the samples and their potential to generate gas. However, the Blue Nile and Dinder Formation have Tmax values in the range of 437 to 456°C, indicating early maturity in the oil window. Thus, higher maturity levels have affected the hydrocarbon generation potential and HI of the samples.

  14. Basic feature of host rock and its relation to the formation of leachable sandstone type uranium deposit in Shihongtan

    International Nuclear Information System (INIS)

    Quan Zhigao; Zhang Jiamin; Ji Haijun; Sun Yanhuan; Zhang Fa

    2012-01-01

    Basic feature of sedimentology and petrology and lithogeochemistry of middle Jurassic Xishanyao formation were discussed for Shihongtan uranium deposit in the paper. The relation between host rock and ore formation was analysed. It is indicated that the formation of Shihongtan uranium deposit de-ponds on the following host features in sedimentology, petrology, lithogeochemistry and the intense oxidized epigenetic alteration under hot dry climate condition during the formation of peneplain caused by the slow tilting uplift. (authors)

  15. Beaufort Formation, eastern Axel Heiberg Island, Canadian Arctic Archipelago

    Energy Technology Data Exchange (ETDEWEB)

    Bustin, R.M.

    1982-07-01

    On eastern Axel Heiberg Island erosional outliers of the Miocene-early Pliocene Beaufort Formation overlie with angular unconformity, or are faulted against, Mesozoic and early Tertiary strata East of Princess Margaret Arch the Beaufort Formation is divisible into three lithofacies: a conglomerate lithofacies interpreted as alluvial-plain deposits, a sandstone conglomerate lithofacies interpreted as distal alluvial-fan deposits and a sandstone-mudstone-siltstone lithofacies interpreted as alluvial-plain deposits. The floodplain was vegetated by a coniferous forest which was characterized by Picea banksii, Larix, Metasequoia and Alnus. Paleocurrent analysis, facies relationships and petrology of the conglomerates and sandstones indicate the provenance of the Beaufort Formation wa Mesozoic strata to the west. Deposition of the Beaufort Formation on eastern Axel Heiberg Island clearly postdates folding of mid-Eocene and older strata and thus provides a minimum age for orogenesis in this part of the Arctic. The occurrence of faulted massiv conglomerates of the Beaufort Formation provides evidence for Miocene-early Pliocene or earlier uplift of ancestral Princess Margaret Arch and a still-later phase of extension.

  16. Evaluation of the Catahoula Formation as a source rock for uranium mineralization, with emphasis on East Texas

    International Nuclear Information System (INIS)

    Ledger, E.B. Jr.

    1981-01-01

    The Oligocene/Miocene Catahoula Formation of the Texas coastal plain is a fluvial and lacustrine volcaniclastic unit composed of normal fluvial material mixed with distal rhyolitic air-fall ash and, in the lower coastal plain, also stream-transported erosion detritus from the volcanic source area in Trans-Pecos Texas and adjacent northern Mexico, the nearest source of appropriate age and chemical affinity. Pedogenic and shallow-burial alteration of the labile volcanic glass component of the sediment resulted in ubiquitous secondary montmorillonite and solubilization of elements which are mobile in a HCO 3 -rich, near-surface environment. Primary uranium present in the glass at 5 to 6 ppMU was similarly mobilized and, under favorable conditions, accumulated by precipitation of tetravalent uranium phases at sites of lower Eh. Known economic deposits are restricted to the lower coastal plain where there has been uranium production for more than twenty years. Although there are differences between the productive lower coastal plain and the middle and upper as to stratigraphy, mineralogical composition, and weathering history, labile volcaniclastic material and its alteration products are abundant throughout the Catahoula outcrop and shallow subsurface in Texas. To provide a geochemical basis of comparison, samples from the upper, middle, and lower Texas coastal plain and the Trans-Pecos source area were analyzed for uranium, thorium, potassium, rubidium, strontium, zirconium, and titanium. These include both labile and immobile elements. Typical levels of these elements in the source material and relatively unaltered Catahoula volcanic glass allows estimation of uranium loss from highly altered sections based on their immobile element content

  17. Investigation into the Formation, Structure, and Evolution of an EF4 Tornado in East China Using a High-Resolution Numerical Simulation

    Science.gov (United States)

    Yao, Dan; Xue, Haile; Yin, Jinfang; Sun, Jisong; Liang, Xudong; Guo, Jianping

    2018-04-01

    Devastating tornadoes in China have received growing attention in recent years, but little is known about their formation, structure, and evolution on the tornadic scale. Most of these tornadoes develop within the East Asian monsoon regime, in an environment quite different from tornadoes in the U.S. In this study, we used an idealized, highresolution (25-m grid spacing) numerical simulation to investigate the deadly EF4 (Enhanced Fujita scale category 4) tornado that occurred on 23 June 2016 and claimed 99 lives in Yancheng, Jiangsu Province. A tornadic supercell developed in the simulation that had striking similarities to radar observations. The violent tornado in Funing County was reproduced, exceeding EF4 (74 m s-1), consistent with the on-site damage survey. It was accompanied by a funnel cloud that extended to the surface, and exhibited a double-helix vorticity structure. The signal of tornado genesis was found first at the cloud base in the pressure perturbation field, and then developed both upward and downward in terms of maximum vertical velocity overlapping with the intense vertical vorticity centers. The tornado's demise was found to accompany strong downdrafts overlapping with the intense vorticity centers. One of the interesting findings of this work is that a violent surface vortex was able to be generated and maintained, even though the simulation employed a free-slip lower boundary condition. The success of this simulation, despite using an idealized numerical approach, provides a means to investigate more historical tornadoes in China.

  18. Granites petrology, structure, geological setting, and metallogeny

    CERN Document Server

    Nédélec, Anne; Bowden, Peter

    2015-01-01

    Granites are emblematic rocks developed from a magma that crystallized in the Earth’s crust. They ultimately outcrop at the surface worldwide. This book, translated and updated from the original French edition Pétrologie des Granites (2011) is a modern presentation of granitic rocks from magma genesis to their crystallization at a higher level into the crust. Segregation from the source, magma ascent and shapes of granitic intrusions are also discussed, as well as the eventual formation of hybrid rocks by mingling/mixing processes and the thermomechanical aspects in country rocks around granite plutons. Modern techniques for structural studies of granites are detailed extensively. Granites are considered in their geological spatial and temporal frame, in relation with plate tectonics and Earth history from the Archaean eon. A chapter on granite metallogeny explains how elements of economic interest are concentrated during magma crystallization, and examples of Sn, Cu, F and U ore deposits are presented. Mi...

  19. South-Tibetan partially molten batholiths: geophysical characterization and petrological assessment of their origin

    Science.gov (United States)

    Hetényi, G.; Pistone, M.; Nabelek, P. I.; Baumgartner, L. P.

    2017-12-01

    Zones of partial melt in the middle crust of Lhasa Block, Southern Tibet, have been geophysically observed as seismically reflective "bright spots" in the past 20 years. These batholiths bear important relevance for geodynamics as they serve as the principal observation at depth supporting channel-flow models in the Himalaya-Tibet orogen. Here we assess the spatial abundance of and partial melt volume fraction within these crustal batholiths, and establish lower and upper estimate bounds using a joint geophysical-petrological approach.Geophysical imaging constrains the abundance of partial melt zones to 5.6 km3 per surface-km2 on average (minimum: 3.1 km3/km2, maximum: 7.6 km3/km2 over the mapped area). Physical properties detected by field geophysics and interpreted by laboratory measurements constrain the amount of partial melt to be between 5 and 26 percent.We evaluate the compatibility of these estimates with petrological modeling based on geotherms, crustal bulk rock compositions and water contents consistent with the Lhasa Block. These simulations determine: (a) the physico-chemical conditions of melt generation at the base of the Tibetan crust and its transport and emplacement in the middle crust; (b) the melt percentage produced at the source, transported and emplaced to form the observed "bright spots". Two main mechanisms are considered: (1) melting induced by fluids produced during mineral dehydration reactions in the underthrusting Indian lower crust; (2) dehydration-melting reactions caused by heating within the Tibetan crust. We find that both mechanisms demonstrate first-order match in explaining the formation of the partially molten "bright spots". Thermal modelling shows that the Lhasa Block batholiths have only small amounts of melt and only for geologically short times (features of the geodynamic evolution. Their transience excludes both long-distance and long-lasting channel flow transport in Tibet.

  20. Air oxidation of samples from different clay formations of East Paris basin: quantitative and qualitative consequences on the dissolved organic matter

    International Nuclear Information System (INIS)

    Blanchart, Pascale; Faure, Pierre; Michels, Raymond; Parant, Stephane

    2012-01-01

    Document available in extended abstract form only. During the excavation and the building of an underground research laboratory in clay geological formations, exposure to air is one of the most important parameters affecting the composition of fossil organic matter. Indeed the net effect of air oxidation of the organic matter is enrichment in oxygen and carbon combined with a loss of hydrogen. Effluents formed are CO 2 and water as well as the liberation of hydrocarbons. This process may have an impact on water chemistry of the clay, especially on the quantity and composition of Dissolved Organic Matter (DOM). The clays studied were the following and may be distinguished on the basis of their organic matter content: - The Callovo-Oxfordian argillite, collected in the Bure Underground Research Laboratory (Meuse, France), which contains a mixture of type II and III kerogen; - The Toarcian shales of East Paris Basin collected from drilling EST 204 (Meuse, France) contains type II kerogen; - The Kimmeridgian shales of East Paris Basin collected from drilling HTM 102 (Meuse, France) also contains type II kerogen. The powdered clay samples were oxidized in a ventilated oven at 100 C under air flow during 2, 256, 512 and 1088 hours for Callovo-Oxfordian samples and during 512 and 2048 hours for Toarcian and Kimmeridgian samples. The DOM of each sample was extracted by soxhlet using pure water. Different analyses were carried out: - Quantitative evolution of DOM with the oxidation process; - Evolution of several chemical parameters of DOM with oxidation using molecular analyses (PyGC-MS) molecular weight distribution (GPC-HPLC) as well as spectroscopic measurements (3D-Fluorescence). Increasing oxidation induces an increase of DOC values for all samples. Also, Changes in the chemical composition of the DOM are observed: decrease in the molecular weight range; enrichment in acidic functional groups (alkane-dioic acids, alkanoic acids, aromatics poly acids). Moreover the

  1. Petrology of lunar rocks and implication to lunar evolution

    Science.gov (United States)

    Ridley, W. I.

    1976-01-01

    Recent advances in lunar petrology, based on studies of lunar rock samples available through the Apollo program, are reviewed. Samples of bedrock from both maria and terra have been collected where micrometeorite impact penetrated the regolith and brought bedrock to the surface, but no in situ cores have been taken. Lunar petrogenesis and lunar thermal history supported by studies of the rock sample are discussed and a tentative evolutionary scenario is constructed. Mare basalts, terra assemblages of breccias, soils, rocks, and regolith are subjected to elemental analysis, mineralogical analysis, trace content analysis, with studies of texture, ages and isotopic composition. Probable sources of mare basalts are indicated.

  2. Petrology, mineralogy and geochemistry of surficial uranium deposits

    International Nuclear Information System (INIS)

    Pagel, M.

    1984-01-01

    A comprehensive understanding of the petrology, mineralogy, and geochemistry of surficial uranium ore deposits is important for developing prospecting and evaluation strategies. Carnotite is the main uranium mineral and is found in those deposits that have the greatest potential uranium resources. The following uranium-bearing minerals have been reported to occur in surficial deposits: carnotite, tyuyamunite, soddyite, weeksite, haiweeite, uranophane, betauranophane, metaankoleite, torbernite, autunite, phosphuranylite, schroeckingerite, Pb-V-U hydroxide (unnamed mineral), uraninite and organourano complexes. The interrelationships between some of the minerals of the host rocks (especially the clays) are not well understood. (author)

  3. INAA and petrological study of sandstones from the Angkor monuments

    International Nuclear Information System (INIS)

    Kucera, J.; Kranda, K.; Soukal, L.; Novak, J.K.; Lang, M.; Poncar, J.; Krausova, I.; Cunin, O.

    2008-01-01

    We determined 35 major, minor and trace elements in sandstone samples taken from building blocks of 19 Angkor temples and from an old and a new quarry using INAA. We also characterized the sandstone samples with conventional microscopy and electron microprobe analysis. Using cluster analysis, we found no straightforward correlation between the chemical/petrological properties of the sandstones and a presumed period of individual temples construction. The poor correlation may result either from the inherent inhomogeneity of sandstone or just reflect the diversity of quarries that supplied building blocks for the construction of any particular temple. (author)

  4. Facies analysis of the Balta Formation: Evidence for a large late Miocene fluvio-deltaic system in the East Carpathian Foreland

    Science.gov (United States)

    Matoshko, Anton; Matoshko, Andrei; de Leeuw, Arjan; Stoica, Marius

    2016-08-01

    Deposits of the Balta Fm are preserved in a large arcuate sediment body that covers about 60,000 km2 and is up to 350 m thick. The Balta Fm spans ca. 5 Ma as constrained by underlying Tortonian (Bessarabian) and overlying Messinian (early Pontian) Paratethys strata. It contains frequent terrestrial mammal fossils and fresh- as well as brackish-water (Paratethys) molluscs and ostracods. Over the past 140 years our understanding of the sedimentary architecture of the formation and its origins has remained in its infancy, which has limited insight into the evolution of the East Carpathian Foreland. Here, we provide the first modern sedimentary facies analysis of the Balta Fm, which is integrated with an extensive review of previously published local literature. It is supported with micropalaeontological results and a wealth of historical borehole information. We show that the Balta Fm has a tripartite vertical division. Its lowermost part is clay dominated and consists of subordinate delta front sand bodies interspersed between muds. The middle unit contains separate delta plain channels or channel belts encased in thick muds. These are overlain by a unit with amalgamated delta plain channel deposits with only minor amounts of associated mud. The abundance of upper flow regime sedimentary structures in channel sands, the absence of peats (or coals) and the presence of calcareous nodules suggest a strongly seasonal and relatively dry climate with a flashy discharge regime. Deposition of the Balta Fm in an area previously characterized by distal shelf and prodelta environments indicates large-scale progradation triggered by high sediment volume from the uplifting Carpathian Orogen and enhanced by a general lowering of Paratethys sea-level. The tripartite internal architecture of the Balta Fm indicates that progradation continued during deposition. Its wedge-shaped geometry suggests that tectonic activity in the Carpathians generated a 300 km wide foreland basin that

  5. Formation of Si-Al-Mg-Ca-rich zoned magnetite in an end-Permian phreatomagmatic pipe in the Tunguska Basin, East Siberia

    Science.gov (United States)

    Neumann, Else-Ragnhild; Svensen, Henrik H.; Polozov, Alexander G.; Hammer, Øyvind

    2017-12-01

    Magma-sediment interactions in the evaporite-rich Tunguska Basin resulted in the formation of numerous phreatomagmatic pipes during emplacement of the Siberian Traps. The pipes contain magnetite-apatite deposits with copper and celestine mineralization. We have performed a detailed petrographic and geochemical study of magnetite from long cores drilled through three pipe breccia structures near Bratsk, East Siberia. The magnetite samples are zoned and rich in Si (≤5.3 wt% SiO2), Ca, Al, and Mg. They exhibit four textural types: (1) massive ore in veins, (2) coating on breccia clasts, (3) replacement ore, and (4) reworked ore at the crater base. The textural types have different chemical characteristics. "Breccia coating" magnetite has relatively low Mg content relative to Si, as compared to the other groups, and appears to have formed at lower oxygen fugacity. Time series analyses of MgO variations in microprobe transects across Si-bearing magnetite in massive ore indicate that oscillatory zoning in the massive ore was controlled by an internal self-organized process. We suggest that hydrothermal Fe-rich brines were supplied from basalt-sediment interaction zones in the evaporite-rich sedimentary basin, leading to magnetite ore deposition in the pipes. Hydrothermal fluid composition appears to be controlled by proximity to dolerite fragments, temperature, and oxygen fugacity. Magnetite from the pipes has attributes of iron oxide-apatite deposits (e.g., textures, oscillatory zoning, association with apatite, and high Si content) but has higher Mg and Ca content and different mineral assemblages. These features are similar to magnetite found in skarn deposits. We conclude that the Siberian Traps-related pipe magnetite deposit gives insight into the metamorphic and hydrothermal effects following magma emplacement in a sedimentary basin.

  6. Sedimentary Petrology: from Sorby to the globalization of Sedimentary Geology

    International Nuclear Information System (INIS)

    Alonso-Zarza, A. M.

    2013-01-01

    We describe here the most important milestones and contributions to Sedimentary Petrology compared to other geological disciplines. We define the main aim of our study and the scientific and economic interests involved in Sedimentary Petrology. The body of the paper focuses upon the historical development of this discipline from Henry Sorby's initial work until the present day. The major milestones in its history include: 1) initial descriptive works; 2) experimental studies; 3) the establishment of the different classifications of sedimentary rocks; 4) studies into facies and sedimentary environments; 5) advances in the study of diagenetic processes and their role in hydrocarbon prospection; and 6) the development of Sedimentary Geochemistry. Relationships and coincidences with Sedimentology are discussed. We go on to look at the advances that have taken place over the last 30 years, in which the study of sedimentary rocks is necessarily included in the wider field of Sedimentary Geology as a logical result of the proposal of global models of a changing Earth in which Sedimentary Geology plays a significant part. Finally we mention the notable contributions of Spanish sedimentary petrologists to this whole field of science. (Author) 120 refs.

  7. Weathering process in Sør Rondane Mountains, East Antarctica

    Science.gov (United States)

    Kanamaru, T.; Suganuma, Y.; Oiwane, H.; Miura, M.; Okuno, J.; Hayakawa, H.

    2016-12-01

    Weathering process under the hyper-arid and hypothermal environment is a key to understand the geomorphogic process and landscape evolution in Antarctica and on Mars. A nunber of studies have focused on weathering process of basaltic rocks in Antarctica, however, the nature of the weathering process of plutonic type rock, a common rock type on the Earth, have been less focused and remain unclear. Here, we report the physical/chemical weathering process of the granitic rocks obtained from Dronning Maud Land in East Antarctica based on a multiplicity of petrological approaches. Loss on Ignition (LOI) and major element composition of the crust and core of the rock samples indicate that chemical weathering process in this area seems to be very limited. The microscopic observations and laser-Raman micro spectroscopy for thin sections from the crust and core indicate that goethite grains are formed mainly in the vein around the crust, which is consistent with the higher Fe3+/Fe2+ contrast from the core to crust. A negative correlation between the rock hardness and color strength index (CSI) values also indicate that crust of rock samples tend to less hard than core due to cracking of the rock samples and following goethite formation. On the other hand, EPMA analysis indicates that original Fe-Ti oxide grains in the core of rock samples are damaged by weathering, and altered to hematite, and to non-stoichiometric Fe-Ti compound associated with ilmenite grans in case of the higher relative height samples. These reveal that the weathering process of the plutonic rocks under the hyper-cold and hypothermal environment are mainly controlled by oxidation, including iron hydroxide formation in the veins formed by mechanical distraction, and Fe-Ti oxide alteration in rock interior.

  8. The petrology and petrogenesis of the Swaldale region, Motzfeldt Center, South Greenland

    Science.gov (United States)

    Reekie, Callum; Finch, Adrian

    2016-04-01

    Motzfeldt is one of several high-level alkaline plutonic centers that collectively define the mid-Proterozoic Gardar Province of South Greenland. Despite pyrochlore-hosted Ta-enrichment (± Nb-Zr-REE), the petrology, geochemistry and petrogenesis across the center remain to be fully constrained. We present petrological and geochemical data for the Swaldale region, an arcuate band of nepheline syenite and associated intrusives on Motzfeldt's NW margin. Work for this present study was undertaken in collaboration with the license holder, Regency Mines plc. Swaldale comprises two geochemically distinct magmatic members. The largest, the Motzfeldt Sø Formation (MSF; EuN/Eu*N = 0.35), is a suite of diverse syenite variants that show significant petrological and geochemical heterogeneity. These rocks have a relatively restricted SiO2 range (57.4-62.9 wt.%) with concurrent variation in (Na+K)/Al (0.75-0.95), Mg/(Mg+Fe) (2.18-19.82) and ΣREE (595.0-3095.9 ppm), emphasizing their evolved but not peralkaline nature. Fractionation is mirrored by pyroxene geochemistry with evolution from aegirine-augite, aegirine-hedenbergite, to aegirine. Accessory pyrochlore, titanite, and zircon are rare; however, anomalous facies of zircon-rich (~2 wt.%) syenite are observed. Intercumulus fluorite is a common accessory within MSF rocks. Hydrothermal alteration, marked by hematized alkali-feldspar, is pervasive and ubiquitous. Further peraluminous syenite of the Geologfjeld Formation ((Na+K)/Al = 0.74; EuN/Eu*N = 1.60) marks the truncated remnant of an early syenite stock to the north of the MSF. These rocks contain salite, which, in addition to a lower ΣREE and higher Mg/(Mg+Fe) (18.01), demonstrates the less-fractionated nature of this stock in comparison with the MSF. Sheeted intrusions of peralkaline syenite ((Na+K)/Al = 1.1; Ta = 32.4 ppm) truncate the MSF across central Swaldale. On a mineralogical basis, it is hypothesized that such intrusions reflect outward sheeting of the

  9. Geological and petrological considerations relevant to the disposal of radioactive wastes by hydraulic fracturing: an example at the US Department of Energy's Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Haase, C.S.

    1982-01-01

    At Oak Ridge National Laboratory the Pumpkin Valley Shale is used as a host formation for hydraulic-fracturing waste disposal. Determination of the relationships between the distribution of different lithologies and porosity-permeability trends within this host formation allows these properties, important to hydraulic-fracturing operations, to be related to measurable and mappable geological and petrological parameters. It also permits extrapolation of such patterns to little-studied portions of the Pumpkin Valley Shale. Such knowledge better allows for the satisfactory operation and assessment of the hydraulic fracturing at Oak Ridge National Laboratory

  10. Geological and petrological considerations relevant to the disposal of radioactive wastes by hydraulic fracturing: an example at the US Department of Energy's Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Haase, C.S.

    1983-01-01

    At Oak Ridge National Laboratory the Pumpkin Valley Shale is used as a host formation for hydraulic fracturing waste disposal. Determination of the relationships between the distribution of different lithologies and porosity-permeability trends within this host formation allows these properties, important to hydraulic fracturing operations, to be related to measurable and mappable geological and petrological parameters. It also permits extrapolation of such patterns to little-studied portions of the Pumpkin Valley Shale. Such knowledge better allows for the satisfactory operation and assessment of the hydraulic fracturing at Oak Ridge National Laboratory

  11. A Magnetic Petrology Database for Satellite Magnetic Anomaly Interpretations

    Science.gov (United States)

    Nazarova, K.; Wasilewski, P.; Didenko, A.; Genshaft, Y.; Pashkevich, I.

    2002-05-01

    A Magnetic Petrology Database (MPDB) is now being compiled at NASA/Goddard Space Flight Center in cooperation with Russian and Ukrainian Institutions. The purpose of this database is to provide the geomagnetic community with a comprehensive and user-friendly method of accessing magnetic petrology data via Internet for more realistic interpretation of satellite magnetic anomalies. Magnetic Petrology Data had been accumulated in NASA/Goddard Space Flight Center, United Institute of Physics of the Earth (Russia) and Institute of Geophysics (Ukraine) over several decades and now consists of many thousands of records of data in our archives. The MPDB was, and continues to be in big demand especially since recent launching in near Earth orbit of the mini-constellation of three satellites - Oersted (in 1999), Champ (in 2000), and SAC-C (in 2000) which will provide lithospheric magnetic maps with better spatial and amplitude resolution (about 1 nT). The MPDB is focused on lower crustal and upper mantle rocks and will include data on mantle xenoliths, serpentinized ultramafic rocks, granulites, iron quartzites and rocks from Archean-Proterozoic metamorphic sequences from all around the world. A substantial amount of data is coming from the area of unique Kursk Magnetic Anomaly and Kola Deep Borehole (which recovered 12 km of continental crust). A prototype MPDB can be found on the Geodynamics Branch web server of Goddard Space Flight Center at http://core2.gsfc.nasa.gov/terr_mag/magnpetr.html. The MPDB employs a searchable relational design and consists of 7 interrelated tables. The schema of database is shown at http://core2.gsfc.nasa.gov/terr_mag/doc.html. MySQL database server was utilized to implement MPDB. The SQL (Structured Query Language) is used to query the database. To present the results of queries on WEB and for WEB programming we utilized PHP scripting language and CGI scripts. The prototype MPDB is designed to search database by major satellite magnetic

  12. Semantically Enabling Knowledge Representation of Metamorphic Petrology Data

    Science.gov (United States)

    West, P.; Fox, P. A.; Spear, F. S.; Adali, S.; Nguyen, C.; Hallett, B. W.; Horkley, L. K.

    2012-12-01

    More and more metamorphic petrology data is being collected around the world, and is now being organized together into different virtual data portals by means of virtual organizations. For example, there is the virtual data portal Petrological Database (PetDB, http://www.petdb.org) of the Ocean Floor that is organizing scientific information about geochemical data of ocean floor igneous and metamorphic rocks; and also The Metamorphic Petrology Database (MetPetDB, http://metpetdb.rpi.edu) that is being created by a global community of metamorphic petrologists in collaboration with software engineers and data managers at Rensselaer Polytechnic Institute. The current focus is to provide the ability for scientists and researchers to register their data and search the databases for information regarding sample collections. What we present here is the next step in evolution of the MetPetDB portal, utilizing semantically enabled features such as discovery, data casting, faceted search, knowledge representation, and linked data as well as organizing information about the community and collaboration within the virtual community itself. We take the information that is currently represented in a relational database and make it available through web services, SPARQL endpoints, semantic and triple-stores where inferencing is enabled. We will be leveraging research that has taken place in virtual observatories, such as the Virtual Solar Terrestrial Observatory (VSTO) and the Biological and Chemical Oceanography Data Management Office (BCO-DMO); vocabulary work done in various communities such as Observations and Measurements (ISO 19156), FOAF (Friend of a Friend), Bibo (Bibliography Ontology), and domain specific ontologies; enabling provenance traces of samples and subsamples using the different provenance ontologies; and providing the much needed linking of data from the various research organizations into a common, collaborative virtual observatory. In addition to better

  13. Study of petrological characteristics of uranium-bearing sandstone in the south of ordos basin, China

    International Nuclear Information System (INIS)

    Tian Cheng; Jia Licheng; Li Song; Zhang Zimin

    2007-01-01

    This paper discusses the relation between uranium-bearing abundance and texture constituent of sedimentary rock, on the basis of the research of petrological characteristic of sandstone in the south of Ordos basin. The influence of infiltration of sandstone and uranium migration and accumulation by the major diagenesis of compaction and cementation, clay minerals evolution, corrosion and forming of secondary porosity are discussed. Uranium-bearing sandstones are divided into four types and their petrological characteristics are discussed. After mineralization conditions being summed up, the uranium-mineralization model of sandstone-type is built. Reliable petrological evidences for evaluating favourable uranium mineralization rich areas are furnished. (authors)

  14. Petrography and geochemistry of selected lignite beds in the Gibbons Creek mine (Manning Formation, Jackson Group, Paleocene) of east-central Texas

    Science.gov (United States)

    Warwick, Peter D.; Crowley, Sharon S.; Ruppert, Leslie F.; Pontolillo, James

    1997-01-01

    This study examined the petrographic and geochemical characteristics of two lignite beds (3500 and 4500 beds, Manning Formation, Jackson Group, Eocene) that are mined at the Gibbons Creek mine in east-central Texas. The purpose of the study was to identify the relations among sample ash yield, coal petrography, and trace-element concentrations in lignite and adjoining rock layers of the Gibbons Creek mine. Particular interest was given to the distribution of 12 environmentally sensitive trace elements (As, Be, Cd, Cr, Co, Hg, Mn, Ni, Pb, Sb, Se, and U) that have been identified as potentially hazardous air pollutants (HAPs) in the United States Clean Air Act Amendments of 1990. Eleven lignite, floor, and rock parting samples were collected from incremental channel samples of the 3500 and 4500 beds that were exposed in a highwall of pit A3 at the Gibbons Creek mine. Short proximate and ultimate and forms of sulfur analyses were performed on all lignite samples, and lignite and rock samples were analyzed for 60 major, minor and trace elements. Representative splits of all lignite samples were ground and cast into pellets, and polished for petrographic analyses in blue-light fluorescence and reflected white light to determine liptinite, inertinite, and huminite maceral group percentages. The following observations summarize our results and conclusions about the geochemistry, petrography, and sedimentology of the 3500 and 4500 beds of the Gibbons Creek lignite deposit: (1) Weighted average dry (db) ash yield for the two beds is 29.7%, average total sulfur content is 2.6%, and average calorific value is 7832 Btu (18.22 MJ/kg). Ash yields are greatest in the lower bench (59.33% db) of the 3500 bed and in the upper bench of the 4500 bed (74.61% db). (2) For lignite samples (on a whole-coal basis), the distributions of two of the HAPs (Pb and Sb) are positively related to ash yield, probably indicating an inorganic affinity for these elements. By using cluster analysis we

  15. Petrology of seamounts in the Central Indian Ocean Basin: Evidence for near-axis origin

    Digital Repository Service at National Institute of Oceanography (India)

    Mukhopadhyay, R.; Batiza, R.; Iyer, S.D.

    Previous studies on the distribution and morphology of ancient seamount chains (>50 Ma) in the Central Indian Ocean basin (CIOB) indicated their generation from the fast spreading Southeast Indian Ridge. The petrology of some of these seamounts...

  16. Origins of cratonic mantle discontinuities: A view from petrology, geochemistry and thermodynamic models

    Science.gov (United States)

    Aulbach, Sonja; Massuyeau, Malcolm; Gaillard, Fabrice

    2017-01-01

    Geophysically detectible mid-lithospheric discontinuities (MLD) and lithosphere-asthenosphere boundaries (LAB) beneath cratons have received much attention over recent years, but a consensus on their origin has not yet emerged. Cratonic lithosphere composition and origin is peculiar due to its ultra-depletion during plume or accretionary tectonics, cool present-day geothermal gradients, compositional and rheological stratification and multiple metasomatic overprints. Bearing this in mind, we integrate current knowledge on the physical properties, chemical composition, mineralogy and fabric of cratonic mantle with experimental and thermodynamic constraints on the formation and migration of melts, both below and within cratonic lithosphere, in order to find petrologically viable explanations for cratonic mantle discontinuities. LABs characterised by strong seismic velocity gradients and increased conductivity require the presence of melts, which can form beneath intact cratonic roots reaching to 200-250 km depth only in exceptionally warm and/or volatile-rich mantle, thus explaining the paucity of seismical LAB observations beneath cratons. When present, pervasive interaction of these - typically carbonated - melts with the deep lithosphere leads to densification and thermochemical erosion, which generates topography at the LAB and results in intermittent seismic LAB signals or conflicting seismic, petrologic and thermal LAB depths. In rare cases (e.g. Tanzanian craton), the tops of live melt percolation fronts may appear as MLDs and, after complete lithosphere rejuvenation, may be sites of future, shallower LABs (e.g. North China craton). Since intact cratons are presently tectonomagmatically quiescent, and since MLDs produce both positive and negative velocity gradients, in some cases with anisotropy, most MLDs may be best explained by accumulations (metasomes) of seismically slow minerals (pyroxenes, phlogopite, amphibole, carbonates) deposited during past

  17. A New Approach to Teaching Petrology: Active Learning in a Studio Classroom

    Science.gov (United States)

    Perkins, D.

    2003-12-01

    During the past 15 years it has become clear that the traditional lecture and lab approach to college science teaching leaves much to be desired. The traditional approach is instructor oriented and based on passive learning. In contrast, current studies show that most students learn best when actively engaged in the learning process. Inquiry based learning and open ended projects have been shown to especially enhance learning by promoting higher order thinking. Recognizing the need for change, however, does not mean the changes are simple. The task of overhauling a course, replacing traditional approaches with more student oriented activities, requires a great deal of time and effort. It also involves much uncertainty and risk. At UND we have been experimenting with alternative pedagogies for a number of years. Change has been incremental, but this year we made wholesale changes in our petrology class. We converted it from the standard three lecture and one lab format to two 3-hour studio sessions per week. The distinction between lab and lecture is gone. In fact, there really are no lectures. The instructor talks for no more than 15 or 20 minutes at a time. Students spend most of their time doing, not listening. We emphasize collaborative active learning projects, some quite short and others lengthy and involved, and use a wide variety of activities. To assess the class, we have an outside consultant and we carry out weekly assessments to measure (1) how students are reacting to the various pedagogical approaches, and (2) how much student learning is actually occurring. This allows us to make adjustments and fine tune as necessary. We could not have made such changes a few years ago, simply because of the amount of work involved to create and test the necessary classroom materials. Today, however, there are many resources available to the reform minded teacher, and the resource base continues to grow. We borrowed heavily from other instructors at other

  18. Field occurrences and petrology of eclogites from the Dabie Mountains, Anhui, central China

    Science.gov (United States)

    Wang, X.; Jing, Y.; Liou, J. G.; Pan, G.; Liang, W.; Xia, M.; Maruyama, S.

    1990-11-01

    Four distinct types of eclogites are recognized according to their field occurrences and mineral parageneses in a gneiss terrane of the Dabie Mountains, a collision zone between the Sino-Korean and Yangtze cratons in central China. Some eclogites contain coesite and its quartz pseudomorphs enclosed in garnet and omphacite. Type I eclogites occur as layers in serpentinites and contain garnet, clinopyroxene, orthopyroxene, phengite, rutile, and coesite pseudomorph. Type II eclogites occur as lenticular bodies inside serpentinites and contain garnet, clinopyroxene, quartz, rutile, and edenitic hornblende. Type III eclogites occur as blocks of 2 cm to 20 m in size in a matrix of hornblende gneiss and biotite gneiss, and Type IV eclogites occur as thin layers interbedded with amphibolites. P- T estimates for these different eclogites indicate that they were formed under different physical conditions. All the eclogites were affected by later regional metamorphism for which the P- T conditions are estimated. This paper provides an introduction to the abundant eclogites from central China which have not been reported previously in Western literature. Specifically, the mode of field occurrence, petrography, mineral chemistry and formation conditions of the four types of eclogites are described. The paper is thus designed to establish a petrological framework for future detailed studies of the eclogites and their country rocks in an ancient zone of collision.

  19. Stratigraphy and Petrology of the Grande Soufriere Hills Volcano, Dominica, Lesser Antilles

    Science.gov (United States)

    Daly, G.; Smith, A. L.; Garcia, R.; Killingsworth, N.

    2007-12-01

    The Grande Soufriere Hills volcanic center is located on the south east coast of the island of Dominica in the Lesser Antilles. Although the volcano is deeply dissected, a distinct circular crater that opens to the east can be observed. Within the crater is a lava dome and unconsolidated pyroclastic deposits mantle the southeast flanks of the volcano. These pyroclastic deposits are almost entirely matrix-supported block and ash flows and surges suggesting that Pelean-style eruptions have dominated its most recent activity. Within this sequence is a relatively thin (30-50 cm) clast-supported deposit that has been interpreted as a possible blast deposit. Two age dates from these younger deposits suggest that much of this activity occurred between l0,000 and 12,000 years ago. On the southeastern coast at Pointe Mulâtre and extending approximately 4 km north and at a maximum 2 km west, is a megabreccia of large (up to 3 m) flow-banded andesite clasts set in a semi-lithified medium grained ash matrix. At Pointe Mulâtre this megabreccia is overlain by unconsolidated block and ash flow deposits. To the north of the megabreccia, exposures in the sea cliffs reveal a consolidated sequence of well-bedded alternating coarse and fine deposits suggesting deltaic foreset beds; which in turn appears to be overlain by a yellow- colored relatively coarse flow deposit with an irregular upper surface. The uppermost deposits in the sea cliffs are a sequence of unconsolidated block and ash flow deposits and interbedded fluviatile conglomerates equivalent to the younger flow deposits logged inland. Volcanic rocks from the Grande Soufriere Hills are all porphyritic andesites often containing hypabyssal inclusions. Dominant phenocrysts are plagioclase often with inclusion-rich cores and well developed zoning. Mafic phenocrysts include hornblende, augite and hypersthene. Geochemically these andesites range from 58- 63% SiO2 and show trends of decreasing values for Al2O3, FeO, MgO, CaO, Ti

  20. Exploring Chondrule and CAI Rims Using Micro- and Nano-Scale Petrological and Compositional Analysis

    Science.gov (United States)

    Cartwright, J. A.; Perez-Huerta, A.; Leitner, J.; Vollmer, C.

    2017-12-01

    As the major components within chondrites, chondrules (mm-sized droplets of quenched silicate melt) and calcium-aluminum-rich inclusions (CAI, refractory) represent the most abundant and the earliest materials that solidified from the solar nebula. However, the exact formation mechanisms of these clasts, and whether these processes are related, remains unconstrained, despite extensive petrological and compositional study. By taking advantage of recent advances in nano-scale tomographical techniques, we have undertaken a combined micro- and nano-scale study of CAI and chondrule rim morphologies, to investigate their formation mechanisms. The target lithologies for this research are Wark-Lovering rims (WLR), and fine-grained rims (FGR) around CAIs and chondrules respectively, present within many chondrites. The FGRs, which are up to 100 µm thick, are of particular interest as recent studies have identified presolar grains within them. These grains predate the formation of our Solar System, suggesting FGR formation under nebular conditions. By contrast, WLRs are 10-20 µm thick, made of different compositional layers, and likely formed by flash-heating shortly after CAI formation, thus recording nebular conditions. A detailed multi-scale study of these respective rims will enable us to better understand their formation histories and determine the potential for commonality between these two phases, despite reports of an observed formation age difference of up to 2-3 Myr. We are using a combination of complimentary techniques on our selected target areas: 1) Micro-scale characterization using standard microscopic and compositional techniques (SEM-EBSD, EMPA); 2) Nano-scale characterization of structures using transmission electron microscopy (TEM) and elemental, isotopic and tomographic analysis with NanoSIMS and atom probe tomography (APT). Preliminary nano-scale APT analysis of FGR morphologies within the Allende carbonaceous chondrite has successfully discerned

  1. Pathways to an East Asian Higher Education Area: A Comparative Analysis of East Asian and European Regionalization Processes

    Science.gov (United States)

    Chao, Roger Y., Jr.

    2014-01-01

    The Author argues that historical regional developments in Europe and East Asia greatly influence the formation of an East Asian Higher Education Area. As such, this article compares European and East Asian regionalization and higher education regionalization processes to show this path dependency in East Asian regionalization of higher education…

  2. Petrology of Oligocene Ghaleh Yaghmesh granitoids in the west of Yazd province

    Directory of Open Access Journals (Sweden)

    Bahareh Fazeli

    2017-02-01

    that magma mixing process was likely responsible for the formation of the rocks being studied. Acknowledgements The authors would like to thank the University of Isfahan for the financial support. We also thank the Southern Methodist University (SMU (Dallas - USA for the XRF chemical analysis undertaken for this project. References Alavi, M., 1994. Tectonics of Zagros orogenic belt of Iran, new data and interpretation. Tectonophysics, 229(3: 211–238. Chappell, B.W. and White, A.J., 1974. Two contrasting granite types. Pacific Geology, 8: 173-174. Clemens, J.D., Stevens G., and Farina, F., 2011. The enigmatic sources of I-type granites: The peritectic conexión. Lithos, 126(3: 174–181. Didier, J., 1991. The main types of enclaves in the Hercynian granitoids of the Massif Central, France. In: J. Didier and B. Barbarin (Editors, Enclaves and Granite Petrology. Developments in Petrology, V. 13. Elsevier, Amsterdam, pp. 47–61. Didier, J. and Barbarin, B., 1991. Enclaves and granite petrology.Developments in Petrology, V. 13. Elsevier, Amsterdam, 625 pp. Ellis, D.J. and Thompson, A.B., 1986. Subsolidus and partial melting reactions in the quartz-excess and water deficient conditions of peraluminous melts from mafic rocks. Journal of Petrology, 27(1: 91-121. Honarmand, M., Rashidnejad-Omran, N., Corfu , F., Emami, M. H. and Nabatian, G., 2013. Geochronology and magmatic history of a calc-alkaline plutonic complex in the Urumieh-Dokhtar Magmatic Belt, Central Iran: Zircon ages as evidence for two major plutonic episodes. Neues Jahrbuch fur Mineralogie, Abhandlungen, 190(1: 67–77. Kananian, A., Sarjoughian, F., Nadimi A., Ahmadian, J. and Ling, W., 2014. Geochemical characteristics of the Kuh-e Dom intrusion, Urumieh–Dokhtar Magmatic Arc (Iran: Implications for source regions and magmatic evolution. Journal of Asian Earth Sciences, 90: 137-148. Sepahi, A.A. and Malvandi, F., 2008. Petrology of the Bouein Zahra-Naein Plutonic Complexes, Urumieh-Dokhtar Belt, Iran: With

  3. Hydrocarbon Prospectivity of Nigeria's Inland Basins: From the View Point of Organic Geochemistry and Organic Petrology

    International Nuclear Information System (INIS)

    Obaje, N. G.; Abubakar, M. B.; Jauro, A.; Tukur, A.; Wehner, H.

    2003-01-01

    The inland basins of Nigeria comprise the Anambra basin, the lower, middle and upper Benue trough, the southeastern sector of the Chad basin, the Mid-Niger (Bida) basin, and the Sokoto basin. Organic geochemical and organic petrologic studies indicate that coal beds constitute major potential source rocks in the whole of the Benue trough (Anambra basin inclusive). The generation and production of liquid and i gaseous hydrocarbons from coal beds presently is world-wide indisputable. In the Anambra basin, the coal beds in the Mamu Formation have TOC contents of up to 60.8wt%, mean Hydrogen Index (HI) of 364mgHC/gTOC, vitrinite reflectivity (Ro) of 0.54 to 0.56% and Tmax 430 to 433degrees C. Biomarker data indicate a dominance of high molecular weight : n-alkanes, very high pristane/phytane ratios, pronounced odd-over-even predominance (OEP), preponderance of C29 regular steranes but with also relatively high contents of C28. In the middle Benue trough, the coal beds of the Awgu Formation have TOC contents of up to 79.1 Owt%, Ro of 0.83 to 1.07%, and mean HI of 281 mgHC/gTOC; unimodal distributions of both low and high molecular weight n-alkanes with no obvious OEP, and a predominance of C29 steranes but also with relatively high contents of C27 and C28. Coal beds from the Lamja Formation in the upper Benue trough yielded TOC contents of up to 50.7wt% with HI of 184mgHC/gTOC, Ro of 0.70 to 0.73%, low and high molecular weights n- alkane dominance with an unpronounced OEP, high pristane/phytane ratios, and very high contents of C29 regular steranes. On a basinal evaluation level, incorporating source rock data from the other formations in the respective sectors, plots on the modified Van Krevelen diagram alongside biomarker and maceral data indicate good i to fair source rock qualities (oil and gas) in the Anambra basin and middle Benue trough; and fair to poor (gaseous to dry) in the upper Benue trough and the Chad basin, with sporadic good to fair source rock

  4. Mineralogy, petrology and geochemistry of the Pocos de Caldas analogue study sites, Minas Gerais, Brazil

    International Nuclear Information System (INIS)

    Waber, M.

    1991-01-01

    The thorium-rare-earth element deposit at Morro do Ferro is of supergene origin and was formed under lateritic weathering conditions. The ore body forms shallow NW-SE elongated argillaceous lenses that extend from the top of the hill downwards along its south-eastern slope. The deposit is capped by a stockwork of magnetite veins which have protected the underlying, highly argillaceous host rock from excessive erosion. The surrounding country rocks comprise a sequence of subvolcanic phonolite intrusions that have been strongly altered by hydrothermal and supergene processes. From petrological, mineralogical and geochemical studies and mass balance calculations, it is inferred that the highly weathered host rock was originally carbonatic in composition and was initially enhanced in thorium and rare-earth elements compared to the surrounding silicate rocks. Intrusion of the carbonatite produced fenitic alteration of the surrounding phonolites, consisting of an early potassic alteration followed by a vein-type Th-REE mineralization with associated fluorite, carbonate, pyrite and zircon. Subsequent lateritic weathering has completely destroyed the carbonatite, forming a residual supergene enrichment of Th and REEs. Initial weathering of the carbonatite leading to solutions enriched in carbonate and phosphate may have appreciably restricted the dissolution of the primary Th-REE phases. Strongly oxidic weathering has resulted in a fractionation between cerium and the other light rare-earth elements. Ce 3+ is oxidized to Ce 4+ and retained together with thorium by secondary mineral formation and adsorption on poorly crystalline iron- and aluminium-hydroxides. In contrast, the trivalent LREEs are retained to a lesser degree and are thus more available for secondary mineral formation and adsorption at greater depths down the weathering column. (author) figs., tabs., 60 refs

  5. The 2003 phreatomagmatic eruptions of Anatahan volcano - Textural and petrologic features of deposits at an emergent island volcano

    Science.gov (United States)

    Pallister, J.S.; Trusdell, F.A.; Brownfield, I.K.; Siems, D.F.; Budahn, J.R.; Sutley, S.F.

    2005-01-01

    Stratigraphic and field data are used in conjunction with textural and chemical evidence (including data from scanning electron microscope, electron microprobe, X-ray fluorescence, X-ray diffraction, and instrumental neutron activation analysis) to establish that the 2003 eruption of Anatahan volcano was mainly phreatomagmatic, dominated by explosive interaction of homogeneous composition low-viscosity crystal-poor andesite magma with water. The hydromagmatic mode of eruption contributed to the significant height of initial eruptive columns and to the excavation and eruption of altered rock debris from the sub-volcanic hydrothermal system. Volatile contents of glass inclusions in equilibrium phenocrysts less abundances of these constituents in matrix glass times the estimated mass of juvenile magma indicate minimum emissions of 19 kt SO2 and 13 kt Cl. This petrologic estimate of SO2 emission is an order-of-magnitude less than an estimate from TOMS. Similarly, inferred magma volumes from the petrologic data are an order of magnitude greater than those modeled from deformation data. Both discrepancies indicate additional sources of volatiles, likely derived from a separate fluid phase in the magma. The paucity of near-source volcanic-tectonic earthquakes preceding the eruption, and the dominance of sustained long-period tremor are attributed to the ease of ascent of the hot low-viscosity andesite, followed by a shallow phreatomagmatic mode of eruption. Phreatomagmatic eruptions are probably more common at emergent tropical island volcanoes, where shallow fresh-water lenses occur at near-sea-level vents. These relations suggest that phreatomagmatic explosions contributed to the formation of many of the near-sea-level craters and possibly even to the small calderas at the other Mariana islands.

  6. Estratigrafía, petrografía sedimentaria y procedencia de las formaciones Sobral y Cross Valley (Paleoceno, isla Marambio (Seymour, Antártica Stratigraphy, sedimentary petrology and provenance of the Sobral and Cross Valley formations (Paleocene, Marambio (Seymour Island, Antarctica

    Directory of Open Access Journals (Sweden)

    Sergio Marenssi

    2012-01-01

    órficos con porcentajes variables de cuarzo y feldespatos. La representación de estas rocas en los diagramas de procedencia indican orógenos reciclados (y mezcla durante los períodos de mayor denudación y arcos disectados a no disectados luego de episodios de vulcanismo activo. El alto porcentaje de cuarzo en algunas secciones señala el enriquecimiento en fragmentos resistentes a partir del retrabajo de las sedimentitas subyacente favorecido por el carácter friable de las mismas y/o el desarrollo de ambientes de sedimentación de alta energía y/o baja velocidad de soterramiento.The unconformity bounded Paleocene Sobral and Cross Valley formations represent part of the uppermost infill of the James Ross Basin of northeastern Antarctic Peninsula. Both units have been subdivided into allomembers since they also present internal unconformities. The Sobral Formation represents silicoclastic sedimentation on a marine shelf during at least two transgressive-regressive cycles. The Cross Valley Formation fills in a narrow valley with volcaniclastic deposits representing an incised valley system with estuarine and subsequent deltaic facies. Sandstones of the Sobral Formation are feldspathic litharenites and lithic arkoses while those of the Cross Valley Formation are feldspathic litharenites to litharenites (volcanic. The sandstone composition (petrofacies of the Sobral and Cross Valley formation suggest provenance from a dissected volcanic arc that increased its activity during the Danian but decline again towards the late Thanetian. A detailed analysis of the sandstone compositional trends allowed to differentiate two petrofacies (S and CV and two sub-petrofacies (S I, S II, CV I and CV II respectively. The sub-petrofacies suggest a control from the sedimentary environments upon the detrital modes and their interference with the true provenance signal. The increase in quartz and glauconite in some units may be related to the unconformities and reworking of the underlying

  7. Petrology of Terra Nova pluton, Brazil, and associated ultrapotassic dykes

    International Nuclear Information System (INIS)

    Silva Filho, A.F. da; Thompson, R.N.; Leat, P.T.

    1987-01-01

    The Upper Precambrian Terra Nova Pluton, situated 550 Km inland from Recife, Brazil, is 220 Km 2 in area and intrudes deformed metasedimentary rocks of the Pianco-Alto Brigida Mobile Belt. The Pluton shows complex petrological relationships. It consists of subalkaline quartz-monzonites and quartz-syenites, and the major minerals are K-feldspars, albite, hornblende, and quartz. The pluton is intermediate in composition (SiO 2 = 58.9-65.6 wt%, MgO=0.9-3.7 wt%) and is dominantly potassic (K 2 O=3.3-5.6 wt %; K 2 O/Na 2 O=0.9-1.8). Ba (up to 2.300 ppm) and Sr (up to 1,100 ppm) are abundant in the rocks, and LREE are enriched relative to HREE (La N /Lu N = 25.6-43.2). There is no significant Eu Anomaly. Rounded autoliths within the pluton are similar, but more mafic in composition (SiO 2 =54.6-57.5 wt %; MgO=4.9-6.4 wt %). A suite of dykes cut pluton and the surrounding country rocks. These dykes are varied in composition, encompassing most of the chemical range shown by the pluton and associated autoliths. The dykes are holocrystalline, peralkaline, and strongly enriched in both K 2 O(K 2 O=5.3-11.4 wt %) and Ba (Ba=2,400 ppm-10,500 ppm), which are considered to be magmatic abundances. The dykes have similar REE and other trace elements and ratios to the autoliths and plutonic rocks, and the dykes and the pluton are thought to be chemically related. The Terra Nova Pluton records the fractionation of mantle-derived ultrapotassic magma from mafic to intermediate compositions. (author) [pt

  8. Geochemistry and petrology of basaltic rocks from the Marshall Islands

    Science.gov (United States)

    Davis, Alice S.; Schwab, William C.; Haggerty, Janet A.

    1986-01-01

    A variety of volcanic rock was recovered from the flanks of seamounts, guyots, atolls, and islands in the Ratak chain of the Marshall Islands on the U.S. Geological Survey cruise L9-84-CP. The main objective of this cruise was to study the distribution and composition of ferromanganese oxide crusts. Preliminary results of managanese crust composition are reported by Schwab et al. (1985) and detailed studies are in preparation (Schwab et al., 1986). A total of seven seafloor edifices were studied using 12 khz, 3.5 khz and air gun seismic reflection, chain dredge and box corer. Bathymetry and ship track lines are presented by Schwab and Bailey (1985). Of the seven edifices surveyed two support atolls (Majuro and Taongi) and one is a tiny island (Jemo). Dredge locations and water depths are given in Table 1 and dredge locations are shown in Figure 1. Due to equipment failures depths of dredge hauls were limited to shallow depth for all except the first two sites occupied. Recovery consisted mostly of young, poorly-consolidated limestone of fore-reef slope deposit and minor volcanogenic breccia and loose talus. The breccia and pieces of talus are thickly encrusted with ferromanganese oxide, whereas the young limestone is only coated by a thin layer. Four of the seven sites surveyed yielded volcanic rock. The volcanic rock, volumetrically a minor part of each dredge haul, consists mostly of lapilli and cobble-size clasts in a calcareous matrix or as loose talus. Most clasts show evidence of reworking, being sub- to well rounded, sometimes with a thin ferromanganese crust of their own. This paper reports preliminary findings on the petrology and geochemistry of volcanic rock recovered.

  9. Geophysical, petrological and mineral physics constraints on Earth's surface topography

    Science.gov (United States)

    Guerri, Mattia; Cammarano, Fabio; Tackley, Paul J.

    2015-04-01

    Earth's surface topography is controlled by isostatically compensated density variations within the lithosphere, but dynamic topography - i.e. the topography due to adjustment of surface to mantle convection - is an important component, specially at a global scale. In order to separate these two components it is fundamental to estimate crustal and mantle density structure and rheological properties. Usually, crustal density is constrained from interpretation of available seismic data (mostly VP profiles) based on empirical relationships such those in Brocher [2005]. Mantle density structure is inferred from seismic tomography models. Constant coefficients are used to interpret seismic velocity anomalies in density anomalies. These simplified methods are unable to model the effects that pressure and temperature variations have on mineralogical assemblage and physical properties. Our approach is based on a multidisciplinary method that involves geophysical observables, mineral physics constraints, and petrological data. Mantle density is based on the thermal interpretation of global seismic tomography models assuming various compositional structures, as in Cammarano et al. [2011]. We further constrain the top 150 km by including heat-flow data and considering the thermal evolution of the oceanic lithosphere. Crustal density is calculated as in Guerri and Cammarano [2015] performing thermodynamic modeling of various average chemical compositions proposed for the crust. The modeling, performed with the code PerpleX [Connolly, 2005], relies on the thermodynamic dataset from Holland and Powell [1998]. Compressional waves velocity and crustal layers thickness from the model CRUST 1.0 [Laske et al., 2013] offer additional constrains. The resulting lithospheric density models are tested against gravity (GOCE) data. Various crustal and mantle density models have been tested in order to ascertain the effects that uncertainties in the estimate of those features have on the

  10. The petrology of the Saaiplaas kimberlite dyke swarm

    International Nuclear Information System (INIS)

    Allan, P.G.

    1990-01-01

    The Saaiplaas 'kimberlite' dykes are part of an east-west trending, roughly vertically dipping dyke swarm that has been intersected at various depths throughout the Orange Free State goldfields. It is shown that the Saaiplaas dykes closely resemble kimberlites in terms of their petrography and geochemistry even though certain features are more characteristic of olivine melilitites or alnoites. 5 refs

  11. Review and update of the applications of organic petrology: Part 2, geological and multidisciplinary applications

    Science.gov (United States)

    Suarez-Ruiz, Isabel; Flores, Deolinda; Mendonça Filho, João Graciano; Hackley, Paul C.

    2012-01-01

    The present paper is focused on organic petrology applied to unconventional and multidisciplinary investigations and is the second part of a two part review that describes the geological applications and uses of this branch of earth sciences. Therefore, this paper reviews the use of organic petrology in investigations of: (i) ore genesis when organic matter occurs associated with mineralization; (ii) the behavior of organic matter in coal fires (self-heating and self-combustion); (iii) environmental and anthropogenic impacts associated with the management and industrial utilization of coal; (iv) archeology and the nature and geographical provenance of objects of organic nature such as jet, amber, other artifacts and coal from archeological sites; and (v) forensic science connected with criminal behavior or disasters. This second part of the review outlines the most recent research and applications of organic petrology in those fields.

  12. Petrologic evolution of CM chondrites: The difficulty of discriminating between nebular and parent-body effects

    Science.gov (United States)

    Kerridge, J. F.; McSween, H. Y., Jr.; Bunch, T. E.

    1994-07-01

    We wish to draw attention to a major controversy that has arisen in the area of CM-chondrite petrology. The problem is important because its resolution will have profound implications for ideas concerning nebular dynamics, gas-solid interactions in the nebula, and accretionary processes in the nebula, among other issues. On the one hand, cogent arguments have been presented that 'accretionary dust mantles,' were formed in the solar nebula prior to accretion of the CM parent asteroid(s). On the other hand, no-less-powerful arguments have been advanced that a significant fraction of the CM lithology is secondary, produced by aqueous alteration in the near-surface regions of an asteroid-sized object. Because most, if not all, CM chondrites are breccias, these two views could coexist harmoniously, were it not for the fact that some of the coarse-grained lithologies surrounded by 'accretion dust mantles' are themselves of apparently secondary origin. Such an observation must clearly force a reassessment of one or both of the present schools of thought. Our objective here is to stimulate such a reassessment. Four possible resolutions of this conflict may be postulated. First, perhaps nature found a way of permitting such secondary alteration to take place in the nebula. Second, maybe dust mantles could form in a regolith, rather than a nebular, environment. Third, it is possible that dust mantles around secondary lithologies are different from those around primary lithologies. Finally, perhaps formation of CM chondrites involved a more complex sequence of events than visualized so far, so that some apparently 'primary' processes postdated certain 'secondary' processes.

  13. The Jurassic of Denmark and Greenland: Palynostratigraphy and palaeoenvironments of the Rævekløft, Gule Horn and Ostreaelv Formations (Lower–Middle Jurassic, Neill Klinter Group, Jameson Land, East Greenland

    Directory of Open Access Journals (Sweden)

    Koppelhus, Eva B.

    2003-10-01

    Full Text Available The Neill Klinter Group of Jameson Land, East Greenland contains rich and diverse palynomorph assemblages. Spores, pollen and freshwater algae dominate most of the samples, but dinoflagellatecysts and acritarchs also form important components. The ages suggested by the palynomorphs from the Rævekløft, Gule Horn and Ostreaelv Formations span the period from the Early Pliensbachian to the early Aalenian. The number of palynomorphs identified totals 136,including 83 miospore and 53 microplankton species; they are grouped into seven palynological assemblage zones.In general, there is good agreement between the palynological and sedimentological data, and the palynological data has refined the understanding of the depositional palaeoenvironments ofthe Neill Klinter Group. In some cases, the boundaries of the palynological assemblage zones are congruent with major sequence stratigraphic surfaces and the palynological data thus supportthe sequence stratigraphic interpretation. In other cases, however, regional correlation indicates that the zone boundaries cross important sequence stratigraphic surfaces, such as sequenceboundaries; such behaviour is thought to reflect the facies-dependent nature of certain of the palynological assemblage zones. The pattern of palynological events in East Greenland has alsobeen recognised on the mid-Norwegian shelf.

  14. Petroleum systems and geologic assessment of undiscovered oil and gas, Cotton Valley group and Travis Peak-Hosston formations, East Texas basin and Louisiana-Mississippi salt basins provinces of the northern Gulf Coast region. Chapters 1-7.

    Science.gov (United States)

    ,

    2006-01-01

    The purpose of the U.S. Geological Survey's (USGS) National Oil and Gas Assessment is to develop geologically based hypotheses regarding the potential for additions to oil and gas reserves in priority areas of the United States. The USGS recently completed an assessment of undiscovered oil and gas potential of the Cotton Valley Group and Travis Peak and Hosston Formations in the East Texas Basin and Louisiana-Mississippi Salt Basins Provinces in the Gulf Coast Region (USGS Provinces 5048 and 5049). The Cotton Valley Group and Travis Peak and Hosston Formations are important because of their potential for natural gas resources. This assessment is based on geologic principles and uses the total petroleum system concept. The geologic elements of a total petroleum system include hydrocarbon source rocks (source rock maturation, hydrocarbon generation and migration), reservoir rocks (sequence stratigraphy and petrophysical properties), and hydrocarbon traps (trap formation and timing). The USGS used this geologic framework to define one total petroleum system and eight assessment units. Seven assessment units were quantitatively assessed for undiscovered oil and gas resources.

  15. Geochemical studies, magmatic evolution, microstructures and replacement mechanisms in Jebale-Barez granitoid Complex (East and Southeast Jiroft)

    OpenAIRE

    Jamal Rasouli; Mansour Ghorbani; Vahid Ahadnejad

    2017-01-01

    Introduction The Jebale-Barez Plutonic Complex (JBPC) is composed of many intrusive bodies and is located in the southeastern province of Kerman on the longitude of the 57◦ 45 ' east to 58◦ 00' and Northern latitudes 28◦ 30' to 29◦ 00'. The petrologic composition is composed of granodiorite, quartzdiorite, granite, alkali-granite, and trace amounts of tonalite with dominant granodiorite composition. Previously, the JBPC was separated into three plutonic phases by Ghorbani (2014). The fi...

  16. On the Grand Challenges in Physical Petrology: the Multiphase Crossroads

    Science.gov (United States)

    Bergantz, G. W.

    2014-12-01

    Rapid progress in experimental, micro-analytical and textural analysis at the crystal scale has produced an unprecedented record of magmatic processes. However an obstacle to further progress is the lack of understanding of how mass, energy and momentum flux associated with crystal-rich, open-system events produces identifiable outcomes. Hence developing a physically-based understanding of magmatic systems linking micro-scale petrological observations with a physical template operating at the macro-scale presents a so-called "Grand Challenge." The essence of this challenge is that magmatic systems have characteristic length and feedback scales between those accessible by classical continuum and discrete methods. It has become increasingly obvious that the old-school continuum methods have limited resolution and power of explanation for multiphase (real) magma dynamics. This is, in part, because in crystal-rich systems the deformation is non-affine, and so the concept of constitutive behavior is less applicable and likely not even relevant, especially if one is interested in the emergent character of micro-scale processes. One expression of this is the cottage industry of proposing viscosity laws for magmas, which serves as "blunt force" de facto corrections for what is intrinsically multiphase behavior. Even in more fluid-rich systems many of these laws are not suitable for use in the very transport theories they aim to support. The alternative approach is the discrete method, where multiphase interactions are explicitly resolved. This is a daunting prospect given the numbers of crystals in magmas. But perhaps all crystals don't need to be modeled. I will demonstrate how discrete methods can recover critical state behavior, resolve crystal migration, the onset of visco-elastic behavior such as melt-present shear bands which sets the large-scale mixing volumes, some of the general morpho-dynamics that underlies purported rheological models, and transient controls on

  17. Insights into the dolomitization process and porosity modification in sucrosic dolostones, Avon Park Formation (Middle Eocene), East-Central Florida, U.S.A.

    KAUST Repository

    Maliva,, Robert G.

    2011-03-01

    The Avon Park Formation (middle Eocene) in central Florida, U.S.A., contains shallow-water carbonates that have been replaced by dolomite to varying degrees, ranging from partially replaced limestones, to highly porous sucrosic dolostones, to, less commonly, low-porosity dense dolostones. The relationships between dolomitization and porosity and permeability were studied focusing on three 305-m-long cores taken in the City of Daytona Beach. Stable-isotope data from pure dolostones (mean δ 18O = +3.91% V-PDB) indicate dolomite precipitation in Eocene penesaline pore waters, which would be expected to have been at or above saturation with respect to calcite. Nuclear magnetic log-derived porosity and permeability data indicate that dolomitization did not materially change total porosity values at the bed and formation scale, but did result in a general increase in pore size and an associated substantial increase in permeability compared to limestone precursors. Dolomitization differentially affects the porosity and permeability of carbonate strata on the scale of individual crystals, beds, and formations. At the crystal scale, dolomitization occurs in a volume-for-volume manner in which the space occupied by the former porous calcium carbonate is replaced by a solid dolomite crystal with an associated reduction in porosity. Dolomite crystal precipitation was principally responsible for calcite dissolution both at the actual site of dolomite crystal growth and in the adjoining rock mass. Carbonate is passively scavenged from the formation, which results in no significant porosity change at the formation scale. Moldic pores after allochems formed mainly in beds that experienced high degrees of dolomitization, which demonstrates the intimate association of the dolomitization process with carbonate dissolution. The model of force of crystallization-controlled replacement provides a plausible explanation for key observations concerning the dolomitization process in the

  18. Insights into the dolomitization process and porosity modification in sucrosic dolostones, Avon Park Formation (Middle Eocene), East-Central Florida, U.S.A.

    KAUST Repository

    Maliva,, Robert G.; Budd, David A.; Clayton, Edward A.; Missimer, Thomas M.; Dickson, John Anthony D

    2011-01-01

    The Avon Park Formation (middle Eocene) in central Florida, U.S.A., contains shallow-water carbonates that have been replaced by dolomite to varying degrees, ranging from partially replaced limestones, to highly porous sucrosic dolostones, to, less commonly, low-porosity dense dolostones. The relationships between dolomitization and porosity and permeability were studied focusing on three 305-m-long cores taken in the City of Daytona Beach. Stable-isotope data from pure dolostones (mean δ 18O = +3.91% V-PDB) indicate dolomite precipitation in Eocene penesaline pore waters, which would be expected to have been at or above saturation with respect to calcite. Nuclear magnetic log-derived porosity and permeability data indicate that dolomitization did not materially change total porosity values at the bed and formation scale, but did result in a general increase in pore size and an associated substantial increase in permeability compared to limestone precursors. Dolomitization differentially affects the porosity and permeability of carbonate strata on the scale of individual crystals, beds, and formations. At the crystal scale, dolomitization occurs in a volume-for-volume manner in which the space occupied by the former porous calcium carbonate is replaced by a solid dolomite crystal with an associated reduction in porosity. Dolomite crystal precipitation was principally responsible for calcite dissolution both at the actual site of dolomite crystal growth and in the adjoining rock mass. Carbonate is passively scavenged from the formation, which results in no significant porosity change at the formation scale. Moldic pores after allochems formed mainly in beds that experienced high degrees of dolomitization, which demonstrates the intimate association of the dolomitization process with carbonate dissolution. The model of force of crystallization-controlled replacement provides a plausible explanation for key observations concerning the dolomitization process in the

  19. Petrologic testament to changes in shallow magma storage and transport during 30+ years of recharge and eruption at Kīlauea Volcano, Hawai‘i: Chapter 8

    Science.gov (United States)

    Thornber, Carl R.; Orr, Tim R.; Heliker, Christina; Hoblitt, Richard P.; Carey, Rebecca; Cayol, Valérie; Poland, Michael P.; Weis, Dominique

    2015-01-01

    Petrologic monitoring of Kīlauea Volcano from January 1983 to October 2013 has yielded an extensive record of glass, phenocryst, melt inclusion, and bulk-lava chemistry from well-quenched lava. When correlated with 30+ years of geophysical and geologic monitoring, petrologic details testify to physical maturation of summit-to-rift magma plumbing associated with sporadic intrusion and prolonged magmatic overpressurization. Changes through time in bulk-lava major- and trace-element compositions, along with glass thermometry, record shifts in the dynamic balance of fractionation, mixing, and assimilation processes inherent to magma storage and transport during near-continuous recharge and eruption. Phenocryst composition, morphology, and texture, along with the sulfur content of melt inclusions, constrain coupled changes in eruption behavior and geochemistry to processes occurring in the shallow magmatic system. For the first 17 years of eruption, magma was steadily tapped from a summit reservoir at 1–4 km depth and circulating between 1180 and 1200°C. Furthermore, magma cooled another 30°C while flowing through the 18 km long rift conduit, before erupting olivine-spinel-phyric lava at temperatures of 1150–1170°C in a pattern linked with edifice deformation, vent formation, eruptive vigor, and presumably the flux of magma into and out of the summit reservoir. During 2000–2001, a fundamental change in steady state eruption petrology to that of relatively low-temperature, low-MgO, olivine(-spinel)-clinopyroxene-plagioclase-phryic lava points to a physical transformation of the shallow volcano plumbing uprift of the vent. Preeruptive comagmatic mixing between hotter and cooler magma is documented by resorption, overgrowth, and compositional zonation in a mixed population of phenocrysts grown at higher and lower temperatures. Large variations of sulfur (50 to >1000 ppm) in melt inclusions within individual phenocrysts and among phenocrysts in most samples

  20. Petrography and petrology of Quaternary volcanic rocks from Ghezel Ghaleh, northwest Qorveh

    Directory of Open Access Journals (Sweden)

    Alireza Bajelan

    2014-10-01

    Full Text Available Introduction In the east and northeast of Sanandaj in the Qorveh-Bijar-Takab axis, there are series of basaltic composition volcanoes with Quaternary age. The study area is part of the Sanandaj-Sirjan zone and is located between 47°52' and 47°57' E longitudes and 35°26 and '35°30' N latitudes. Due to the location of the volcanic cone on Pliocene clastic sediments and Quaternary travertine, the age of these volcanoes is considered to be Quaternary. The cones mostly consist of low scoria, ash, volcanic bombs, lapilli deposits and basaltic lava (Moein Vaziri and Aminsobhani, 1985. Petrological and geochemical studies have been carried out to evaluate Quaternary magmatism in the area and to determine the nature of the lithological characteristics, such as the evaluation of source rocks and magma type, degree of partial melting and the tectonic setting of Ghezel Ghaleh rocks (Moein Vaziri, 1997. Simplified geological map of the study area is characterized by ER-Mapper software. Materials and methods In the course of field studies in the region, 40 samples were taken, 30 thin sections were prepared and polished. XRD analyses were performed on some whole rock samples. All major, minor and trace elements were assessed by ICP-MS at Lab Weft Laboratory in Australia. Results Based on the classification of structural zones, the area is located in the Sanandaj-Sirjan zone, hundred kilometers away from the main Zagros thrust along the NW-SE direction. After early Cimmerian orogeny, andesitic volcanic activity took place (Moein Vaziri and Aminsobhani, 1985. A major secondary mineral in these rocks is iddingsite, formed by hydration and oxidation of the olivine (Shelley, 1993. According to SiO2 against Na2O + K2O (TAS diagram (Irvine and Baragar , 1971 and cationic R1 and R2 diagram (De La Roche et el., 1980, volcanic rocks of the area indicate alkaline series. Discussion To obtain more information on the tectonic setting of these rocks, the Zr/Y-Zr diagram

  1. Detailed cross sections of the Eocene Green River Formation along the north and east margins of the Piceance Basin, western Colorado, using measured sections and drill hole information

    Science.gov (United States)

    Johnson, Ronald C.

    2014-01-01

    This report presents two detailed cross sections of the Eocene Green River Formation in the Piceance Basin, northwestern Colorado, constructed from eight detailed measured sections, fourteen core holes, and two rotary holes. The Eocene Green River Formation in the Piceance Basin contains the world’s largest known oil shale deposit with more than 1.5 billion barrels of oil in place. It was deposited in Lake Uinta, a long-lived saline lake that once covered much of the Piceance Basin and the Uinta Basin to the west. The cross sections extend across the northern and eastern margins of the Piceance Basin and are intended to aid in correlating between surface sections and the subsurface in the basin.

  2. East African Orthopaedic Journal: Submissions

    African Journals Online (AJOL)

    Author Guidelines. The East African Orthopaedic Journal is published biannually by the Kenya Orthopaedics Association. Its primary objective is to give researchers in orthopaedics and ... Format should be as follows; Details of authors as for original articles, summary of not more than 200 words, introduction, case report,

  3. An integrated study of geochemistry and mineralogy of the Upper Tukau Formation, Borneo Island (East Malaysia): Sediment provenance, depositional setting and tectonic implications

    Science.gov (United States)

    Nagarajan, Ramasamy; Roy, Priyadarsi D.; Kessler, Franz L.; Jong, John; Dayong, Vivian; Jonathan, M. P.

    2017-08-01

    An integrated study using bulk chemical composition, mineralogy and mineral chemistry of sedimentary rocks from the Tukau Formation of Borneo Island (Sarawak, Malaysia) is presented in order to understand the depositional and tectonic settings during the Neogene. Sedimentary rocks are chemically classified as shale, wacke, arkose, litharenite and quartz arenite and consist of quartz, illite, feldspar, rutile and anatase, zircon, tourmaline, chromite and monazite. All of them are highly matured and were derived from a moderate to intensively weathered source. Bulk and mineral chemistries suggest that these rocks were recycled from sedimentary to metasedimentary source regions with some input from granitoids and mafic-ultramafic rocks. The chondrite normalized REE signature indicates the presence of felsic rocks in the source region. Zircon geochronology shows that the samples were of Cretaceous and Triassic age. Comparable ages of zircon from the Tukau Formation sedimentary rocks, granitoids of the Schwaner Mountains (southern Borneo) and Tin Belt of the Malaysia Peninsular suggest that the principal provenance for the Rajang Group were further uplifted and eroded during the Neogene. Additionally, presence of chromian spinels and their chemistry indicate a minor influence of mafic and ultramafic rocks present in the Rajang Group. From a tectonic standpoint, the Tukau Formation sedimentary rocks were deposited in a passive margin with passive collisional and rift settings. Our key geochemical observation on tectonic setting is comparable to the regional geological setting of northwestern Borneo as described in the literature.

  4. Influence of a major exposure surface on the development of microporous micritic limestones - Example of the Upper Mishrif Formation (Cenomanian) of the Middle East

    Science.gov (United States)

    Deville de Periere, M.; Durlet, C.; Vennin, E.; Caline, B.; Boichard, R.; Meyer, A.

    2017-05-01

    Microporous platform top limestones of the Cenomanian Mishrif Formation (offshore Qatar) were studied in order to investigate the diagenetic processes associated with the top-Mishrif subaerial unconformity and its influence on the development of microporosity in underlying carbonates. Petrographical and stable isotope results indicate that complex diagenetic changes occurred during subaerial exposure of the Mishrif Formation, including pervasive dissolution and meteoric cementation, as well as neomorphism of the micritic matrix. Micrites at the top of the Mishrif Formation are coarse (i.e. > 2 μm), sub-rounded and very dull luminescent under cathodoluminescence. In this uppermost part of the studied interval, the limestone matrix first underwent dissolution of unstable grains in the vadose zone, with subsequent precipitation of low-magnesium calcite (LMC) overgrowths within an oxidising phreatic setting. This process explains the poor luminescence of the micrite crystals and their relatively coarse crystallometry which results in the present day in relatively good reservoir properties. δ13C ratios within the microporous limestones are negative (up to - 4‰ V-PDB) due to the incorporation of isotopically light carbon derived from palaeosols which developed during exposure. By contrast, fine (i.e. aquifer associated with the Top-Mishrif Unconformity, and were precipitated from meteoric or mixed dysoxic waters which were slightly supersaturated with respect to calcite.

  5. Petrological and geochemical studies of mantle xenoliths from La Palma, Canary Islands

    Science.gov (United States)

    Janisch, Astrid; Ntaflos, Theodoros

    2015-04-01

    La Palma is the second youngest island, after El Hierro, of the Canary archipelago. The archipelago consists of seven large islands, forming an east-west-trending island chain, and several seamounts. All together they form a volcanic belt of around 800 km length and 450 km width, which presumably comprises roughly the Canary hotspot. The islands are located off the western coast of Morocco, Africa. The distance ranges from 100 km to 500 km. Concurrently with the distance, subaerial volcanism age progresses from the oldest lava in the east to the youngest in the west of the archipelago. Presently, La Palma is in the shield building stage of growth (alongside with El Hierro and Tenerife) and is furthermore the fastest growing island of the Canary archipelago. Historical volcanic eruptions are restricted on the younger islands, La Palma and El Hierro, with the last eruption at the south end of La Palma in 1971. Mantle xenoliths described in this work were collected at the slopes of San Antonio Volcano, Fuencaliente, brought to the surface during the 1677/1678 eruption. The mantle xenolith collection comprises sp-lherzolites, sp-harzburgites and pyroxenites. The texture can be distinguished between coarse-grained matrix and fine-grained veins in various thicknesses, mostly with olivine and pyroxene but also with amphibole, phlogopite as well as apatite. Mineral analyses reveal the existence of primary and secondary ol, cpx and opx. Primary ol has Fo contents of 89.2 to 91.7 and NiO ranging from 0.3 to 0.45 wt.%, whereas secondary ol show Fo values of 78.4 to 91.9 but with NiO below 0.3 wt.%. Primary cpx are predominantly Cr-Diopsides with En48.7-51.9-Wo43.5-44.3-Fs4.1-4.9 and Mg# of 91.5 to 92.4. Secondary cpx, primarily Ti-Augit, display En36.7-44.4-Wo47.7-49.6-Fs6.7-13.0 and Mg# of 75.3 to 90.8. Primary opx compositions are in range of En89.3-90.6-Wo1.3-1.5-Fs8.1-9.3 with Mg# between 90.7 and 92.0. Secondary opx exhibit En88.7-89.2-Wo1.7-1.9-Fs9.1-9.5 and Mg# of 90

  6. 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…

  7. Upper Cretaceous to Pleistocene melilitic volcanic rocks of the Bohemian Massif: Petrology and mineral chemistry

    Czech Academy of Sciences Publication Activity Database

    Skála, Roman; Ulrych, Jaromír; Krmíček, Lukáš; Fediuk, F.; Balogh, K.; Hegner, E.

    2015-01-01

    Roč. 66, č. 3 (2015), s. 197-216 ISSN 1335-0552 Institutional support: RVO:67985831 Keywords : Bohemian Massif * Cenozoic volcanism * isotope geochemistry * melilitic rock * mineralogy * petrology Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.523, year: 2015

  8. Assessment of fire-damaged concrete. Combining metamorphic petrology and concrete petrography

    NARCIS (Netherlands)

    Larbi, J.A.; Nijland, T.G.

    2001-01-01

    Metamorphic petrology is a branch of geology that deals with the study of changes in rocks due changing physio-chemical conditions. As conditions shift in or out of the thermodynamic stability field of phases, new phases may appear whereas others disappear. A basic approach is mapping of so-called

  9. Geochemistry and petrology of mafic Proterozoic and Permian dykes on Bornholm, Denmark:

    DEFF Research Database (Denmark)

    Holm, Paul Martin; Pedersen, Lise E.; Højsteeen, Birte

    2010-01-01

    More than 250 dykes cut the mid Proterozoic basement gneisses and granites of Bornholm. Most trend between NNW and NNE, whereas a few trend NE and NW. Field, geochemical and petrological evidence suggest that the dyke intrusions occurred as four distinct events at around 1326 Ma (Kelseaa dyke...

  10. Multi-year application of WRF-CAM5 over East Asia-Part I: Comprehensive evaluation and formation regimes of O 3 and PM 2.5

    Energy Technology Data Exchange (ETDEWEB)

    He, Jian; Zhang, Yang; Wang, Kai; Chen, Ying; Leung, L. Ruby; Fan, Jiwen; Li, Meng; Zheng, Bo; Zhang, Qiang; Duan, Fengkui; He, Kebin

    2017-09-01

    Accurate simulations of air quality and climate require robust model parameterizations on regional and global scales. The Weather Research and Forecasting model with Chemistry version 3.4.1 has been coupled with physics packages from the Community Atmosphere Model version 5 (CAM5) (WRF-CAM5) to assess the robustness of the CAM5 physics package for regional modeling at higher grid resolutions than typical grid resolutions used in global modeling. In this two-part study, Part I describes the application and evaluation of WRF-CAM5 over East Asia at a horizontal resolution of 36-km for six years: 2001, 2005, 2006, 2008, 2010, and 2011. The simulations are evaluated comprehensively with a variety of datasets from surface networks, satellites, and aircraft. The results show that meteorology is relatively well simulated by WRF-CAM5. However, cloud variables are largely or moderately underpredicted, indicating uncertainties in the model treatments of dynamics, thermodynamics, and microphysics of clouds/ices as well as aerosol-cloud interactions. For chemical predictions, the tropospheric column abundances of CO, NO2, and O3 are well simulated, but those of SO2 and HCHO are moderately overpredicted, and the column HCHO/NO2 indicator is underpredicted. Large biases exist in the surface concentrations of CO, NO2, and PM10 due to uncertainties in the emissions as well as vertical mixing. The underpredictions of NO lead to insufficient O3 titration, thus O3 overpredictions. The model can generally reproduce the observed O3 and PM indicators. These indicators suggest to control NOx emissions throughout the year, and VOCs emissions in summer in big cities and in winter over North China Plain, North/South Korea, and Japan to reduce surface O3, and to control SO2, NH3, and NOx throughout the year to reduce inorganic surface PM.

  11. Heat and mass transportation as factor of formation abnormally high stratum pressure (on the example of the east part of Dniper-Donets cavity

    Directory of Open Access Journals (Sweden)

    Vasily Suyarko

    2016-06-01

    Full Text Available On the example of the eastern part of the Dnieper-Donets cavity (DDC considered the role of the heat and mass transportation in the Earth's crust as a factor of the formation of abnormally high stratum pressure (AHPS. Investigated the regularity of the spatial distribution geochemical and positive anomalies of thermal field as indicators of AHPS zones.Established restriction sites abnormally-high reservoir pressure to areas of deep faults activated and drawn schematic map of the distribution of abnormally high reservoir-ticks 

  12. Accuracy assessment of digital surface models based on a small format action camera in a North-East Hungarian sample area

    Directory of Open Access Journals (Sweden)

    Barkóczi Norbert

    2017-01-01

    Full Text Available The use of the small format digital action cameras has been increased in the past few years in various applications, due to their low budget cost, flexibility and reliability. We can mount these small cameras on several devices, like unmanned air vehicles (UAV and create 3D models with photogrammetric technique. Either creating or receiving these kind of databases, one of the most important questions will always be that how accurate these systems are, what the accuracy that can be achieved is. We gathered the overlapping images, created point clouds, and then we generated 21 different digital surface models (DSM. The differences based on the number of images we used in each model, and on the flight height. We repeated the flights three times, to compare the same models with each other. Besides, we measured 129 reference points with RTK-GPS, to compare the height differences with the extracted cell values from each DSM. The results showed that higher flight height has lower errors, and the optimal air base distance is one fourth of the flying height in both cases. The lowest median was 0.08 meter, at the 180 meter flight, 50 meter air base distance model. Raising the number of images does not increase the overall accuracy. The connection between the amount of error and distance from the nearest GCP is not linear in every case.

  13. Petrology of forearc basalt-related isotropic gabbros from the Bonin Ridge, Izu-Bonin forearc

    Science.gov (United States)

    Garcia, S. E.; Loocke, M. P.; Snow, J. E.

    2017-12-01

    The early arc volcanic rocks exposed on the Bonin Ridge (BR), a large forearc massif in the Izu-Bonin arc, have provided us with a natural laboratory for the study of subduction initiation and early arc development. The BR has been the subject of focused sampling by way of dredging, diving, and drilling (IODP EXP352) expeditions which have revealed a composite stratigraphy consisting, from bottom to top, of intercalated peridotites and gabbros, isotropic gabbros, sheeted dykes, and a lava sequence which transitions from forearc basalt (FAB) to more arc-like volcanics up section. Although little has been published regarding the moho-transition zone rocks of the BR in comparison to the volcanic rocks, even less work has been published regarding the isotropic gabbros recovered in close association with FABs. Ishizuka et al. (2011) determined that the isotropic gabbros are compositionally and temporally related to the FABs. We provide the first petrologic characterization, including petrography and electron probe microanalysis, of a suite of FAB-related gabbros recovered by dredge D42 of the 2007 R/V Hakuho Maru KH07-02 dredging cruise. Preliminary petrographic observations of the fourteen thin sections reveal that all of the samples contain variable amounts of relict orthopyroxene and consist of five disseminated oxide gabbros, 5 oxide gabbros, and 2 gabbros. We note that all of the D42 gabbros exhibit strong textural variability akin to the varitextured gabbros described in the dyke-gabbro transition of ophiolites (e.g., MacLeod and Yaouancq, 2000). Geochemical data from this critically understudied horizon have the potential to inform regarding the nature of crustal accretion during subduction initiation and the formation, migration, and evolution of FABs. Further, with many authors comparing the volcanic record and crustal stratigraphy of the BR to ophiolites (e.g., Ishizuka et al., 2014), these data would provide another in situ analogue for comparison with the

  14. A coupled petrological-geodynamical model to investigate the evolution of crustal magmatic systems

    Science.gov (United States)

    Kaus, B. J. P.; Rummel, L.; White, R. W.

    2017-12-01

    The evolution of crustal magmatic systems can be analyzed from different physical and chemical perspectives. Most previous work focus either on the petrological side (considering thermal effects and ignoring mechanics), or on the mechanical evolution (assuming a fixed melt chemistry). Here, we consider both by combining a 2D finite element code, MVEP2, with a thermodynamic modelling approach (Perple_X). Density, melt fraction and the chemical composition of the liquid and solid phase are computed for different starting rock compositions and the evolving chemistry is tracked on markers via 10 main oxides (SiO2-TiO2-Al2O3-Cr2O3-MgO-FeO-CaO-Na2O-K2O-H2O). As soon as the local chemistry changes due to melt extraction, new phase diagrams are computed based on the residual solid chemistry for the deflated magma chamber or on the liquid chemistry for newly generated magma filled fractures. To investigate the chemical evolution in magma chambers and magma filled fractures, we inject mafic sills periodically at varying depth levels into the continental crust. The initial sill injections are focused in either one or two main zones in the crust and may interact with each other. The formation of magma filled fractures from this partially molten zone is tracked with a semi analytical dike initiation algorithm that forms new dikes as a function of the local stress field above the partially molten region and subsequently depletes and compacts the magma source region. Dike generation is thus affected by the background strain rate, amount and depth of melt accumulations as well as parameters that control the plastic and viscous behaviour of the crust (e.g. cohesion, viscous creep flow low etc.). Results show that magma filled fractures triggered by sill injections preferentially form under extensional conditions, particularly within the middle crust (in ca. 25 km depth). Magma chambers in the lower continental crust, on the other hand, are stable over a longer period of time due a

  15. Comparative study of hydrographic conditions for algal bloom formation in the coastal waters of east and west of Hong Kong during 1998

    Science.gov (United States)

    Fang, Hongda; Tang, Senming

    2009-02-01

    Phytoplankton abundance was found to be positively correlated with seasonal changes of seawater temperature in Port Shelter and Lamma Channel, Hong Kong in 1998. Rising water temperature from around 20°C to 25°C coincided with an increase in phytoplankton abundance at both locations. Heavy rains from June to September reduced salinity from 30 to 20, but the decrease in salinity was not correlated with a decline in phytoplankton abundance. In spring 1998, over 0.6×106 cells dm-3 and 0.1×106 cells dm-3 of the dinoflagellate, Gymnodinium mikimotoi Miyake et Kominami ex Oda occurred in the coastal waters of Port Shelter and Lamma Channel, respectively. High abundance of the dinoflagellate Ceratium furca (Ehr.) Claparede et Lachmann (>1×106 cells dm-3) produced long-lasting blooms in the waters of Port Shelter from September to October in 1998. The abundances of both diatoms and dinoflagellates were significantly lower in the waters of Lamma Channel than those in Port Shelter due to the less frequent blooms in 1998. Hydrographic conditions such as stable water masses and water column stratification were the main reasons for the differences in the algal abundance and bloom frequency found between the two locations since neither of the two areas appeared to be nutrient-limited. This type water condition for the formation of algal bloom in Port Shelter has not been reported previously and it is not a general case for many bays along China’s coast where algal bloom occurs as well.

  16. Petrologic perspectives on tectonic evolution of a nascent basin (Okinawa Trough) behind Ryukyu Arc:A review

    Institute of Scientific and Technical Information of China (English)

    YAN Quanshu; SHI Xuefa

    2014-01-01

    Okinawa Trough is a back-arc, initial marginal sea basin, located behind the Ryukyu Arc-Trench System. The formation and evolution of the Okinawa Trough is intimately related to the subduction process of the Philippine Sea Plate beneath the Eurasian Plate since the late Miocene. The tectonic evolution of the trough is similar to other active back-arcs, such as the Mariana Trough and southern Lau Basin, all of which are experiencing the initial rifting and subsequent spreading process. This study reviews all petrologic and geochemical data of mafic volcanic lavas from the Okinawa Trough, Ryukyu Arc, and Philippine Sea Plate, combined with geophysical data to indicate the relationship between the subduction sources (input) and arc or back-arc magmas (output) in the Philippine Sea Plate-Ryukyu Arc-Okinawa Trough system (PROS). The results obtained showed that several components were variably involved in the petrogenesis of the Oki-nawa Trough lavas:sub-continental lithospheric mantle underlying the Eurasian Plate, Indian mid-oceanic ridge basalt (MORB)-type mantle, and Pacific MORB-type mantle. The addition of shallow aqueous fluids and deep hydrous melts from subducted components with the characteristics of Indian MORB-type mantle into the mantle source of lavas variably modifies the primitive mantle wedge beneath the Ryukyu and sub-continental lithospheric mantle (SCLM) beneath the Okinawa Trough. In the northeastern end of the trough and arc, instead of Indian MORB-type mantle, Pacific MORB-type mantle dominates the magma source. Along the strike of the Ryukyu Arc and Okinawa Trough, the systematic variations in trace element ratios and isotopic compositions reflect the first-order effect of variable subduction input on the magma source. In general, petrologic data, combined with geophysical data, imply that the Okinawa Trough is experiencing the“seafloor spreading”process in the southwest segment,“rift propagation”process in the middle seg-ment, and

  17. New Petrology, Mineral Chemistry and Stable MG Isotope Compositions of an Allende CAI: EK-459-7-2

    Science.gov (United States)

    Jeffcoat, C. R.; Kerekgyarto, A. G.; Lapen, T. J.; Righter, M.; Simon, J. I.; Ross, D. K.

    2016-01-01

    Calcium-aluminum-rich inclusions (CAIs) are the key to understanding physical and chemical conditions in the nascent solar nebula. These inclusions have the oldest radiometric ages of solar system materials and are composed of phases that are predicted to condense early from a gas of solar composition. Thus, their chemistry and textures record conditions and processes in the earliest stages of development of the solar nebula. Type B inclusions are typically larger and more coarse grained than other types with substantial evidence that many of them were at least partially molten. Type B inclusions are further subdivided into Type B1 (possess thick melilite mantle) and Type B2 (lack melilite mantle). Despite being extensively studied, the origin of the melilite mantles of Type B1 inclusions remains uncertain. We present petrologic and chemical data for a Type B inclusion, EK-459-7-2, that bears features found in both Type B1 and B2 inclusions and likely represents an intermediate between the two types. Detailed studies of more of these intermediate objects may help to constrain models for Type B1 rim formation.

  18. The role of amphibole in Merapi arc magma petrogenesis: insights from petrology and geochemistry of lava hosted xenoliths and xenocrysts

    Science.gov (United States)

    Chadwick, J. P.; Troll, V. R.; Schulz, B.; Dallai, L.; Freda, C.; Schwarzkopf, L. M.; Annersten, H.; Skogby, H.

    2010-05-01

    Recently, increasing attention has been paid to the role of amphibole in the differentiation of arc magmas. The geochemical composition of these magmas suggests that deep to mid crustal fractionation of amphibole has occurred. However, this phase is typically an infrequent modal phenocryst phase in subduction zone eruptive deposits(1). Nevertheless, erupted material only represents a portion of the magmatism produced in subduction zone settings, with many opportunities for melts to stall on route to the surface. This discrepancy between whole rock geochemistry and petrological interpretation of arc magmas has lead many scientists to postulate that, at mid to deep crustal levels, there may be significant volumes of amphibole bearing lithologies. Amphibole instability at shallow levels can also contribute to its scarcity in eruptive deposits. This argument is strengthened by field and petrological evidence, including the widespread occurrence of amphibole-rich intrusive rocks in exhumed orogenicbelts formed during subduction zone activity, e.g. the Adamello batholith (2),as well as the presence of amphibole-rich xenoliths and xenocrysts preserved in arc lavas worldwide, e.g. in Indonesia, Antilles, and Central America. Thus, amphibole appears to play an integral role in subduction zone magmatism and identifying and constraining this role is central to understanding arc magma petrogenisis. Amphibole-rich melts or bodies in the deep to mid crust could be a significant hydrous reservoir for intra-crustal melts and fluids (1). In this preliminary study, we have carried out petrological and geochemical analyses of recent basaltic andesite and amphibole bearing crystalline igneous inclusions and xenocrysts from Merapi volcano in Java, Indonesia. The basaltic andesite geochemistry is consistent with amphibole fractionation and the crystalline inclusions are cogenetic to the Merapi magmatic system. These inclusions are likely to represent fractionation residues reflecting

  19. Petrologic Aspects of Seamount and Guyot Volcanism on the Ancestral Mesozoic Pacific Plate: a Review

    Science.gov (United States)

    Natland, J. H.

    2007-12-01

    Hundreds of large seamounts and guyots are widely scattered almost in a "shotgun-blast" arrangement in an area about the size of the United States west of the Mississippi River on the Mesozoic Pacific plate between the Mariana Trench and the Gilbert Islands. Most of these formed between ~160-100 Ma while the Pacific plate was surrounded by spreading ridges and growing outward in all directions. There is little to no indication that the seamounts and guyots formed along linear seamount chains; existing radiometric-age data show no age progressions. The volcanoes appear to have formed in response to a uniform stress configuration across the plate, which was either not moving or moving very slowly at the time (1, 2), much like the modern Antarctic plate. When the growing plate started to encounter subduction systems in the western Pacific at ~90 Ma, consistent stress patterns began to develop, and the broad linear Gilbert and Line volcanic ridge systems began to form. Even then, however, considerable overlapping of volcanism occurred, and only the most general age progressions are evident in existing data. Petrologic data from samples obtained from dozens of volcanic summits by dredging and beneath several carbonate platforms by drilling reveal considerable diversity in development of differentiated alkalic magmatic lineages rooted in diverse parental basaltic rocks. These include transitional, alkalic and basanitic compositions, with differentiates of hawaiite, mugearite, trachyte and one phonolite. Many of the basaltic rocks are partly to significantly transformed by alteration under oxidative conditions (dredged rocks) and both oxidative and non-oxidative conditions (drilled rocks). This can make estimations of mantle geochemical provenance difficult. Nevertheless, the province has been linked by backtracking techniques to the modern SOPITA region of the South Pacific (3), and its rocks show enrichments in trace elements and isotopic characteristics similar to

  20. Petrology and Wavespeeds in Central Tibet Indicate a Partially Melted Mica-Bearing Crust

    Science.gov (United States)

    Hacker, B. R.; Ritzwoller, M. H.; Xie, J.

    2013-12-01

    S-wave speeds and Vp/Vs ratios in the middle to deep crust of Tibet are best explained by a partially melted, mica-bearing middle to lower crust with a subhorizontal to gently dipping foliation. Surface-wave tomography [e.g., Yang et al., 2012; Xie et al., 2013] shows that the central Tibetan Plateau (the Qiangtang block) is characterized by i) slow S-wave speeds of 3.3-3.5 km/s at depths from 20-25 km to 45-50 km, ii) S-wave radial anisotropy of at least 4% (Vsh > Vsv) with stronger anisotropy in the west than the east [Duret et al., 2010], and iii) whole-crust Vp/Vs ratios in the range of 1.73-1.78 [Xu et al., 2013]. The depth of the Curie temperature for magnetite inferred from satellite magnetic measurements [Alsdorf and Nelson, 1999], the depth of the α-β quartz transition inferred from Vp/Vs ratios [Mechie et al., 2004], and the equilibration pressures and temperatures of xenoliths erupted from the mid-deep crust [Hacker et al., 2000] indicate that the thermal gradient in Qiangtang is steep, reaching 1000°C at 30-40 km depth. This thermal gradient crosses the dehydration-melting solidi for crustal rocks at 20-30 km depth, implying the presence or former presence of melt in the mid-deep crust. These temperatures do not require the wholesale breakdown of mica at these depths, because F and Ti can stabilize mica to at least 1300°C [Dooley and Patino Douce, 1996]. Petrology suggests, then, that the Qiangtang middle to deep crust consists of a mica-bearing residue from which melt has been extracted or is being extracted. Wavespeeds calculated for mica-bearing rocks with a subhorizontal to gently dipping foliation and minor silicate melt are the best match to the wavespeeds and anisotropy observed by seismology. Alsdorf, D., and D. Nelson, The Tibetan satellite magnetic low: Evidence for widespread melt in the Tibetan crust?, Geology, 27, 943-946, 1999. Dooley, D.F., and A.F. Patino Douce, Fluid-absent melting of F-rich phlogopite + rutile +quartz, American

  1. Chapter 7. The GIS project for the geologic assessment of undiscovered oil and gas in the Cotton Valley group and Travis Peak and Hosston formations, East Texas basin and Louisiana-Mississippi salt basins provinces.

    Science.gov (United States)

    Biewick, Laura

    2006-01-01

    A geographic information system (GIS) focusing on the Upper Jurassic-Lower Cretaceous Cotton Valley Group and the Lower Cretaceous Travis Peak and Hosston Formations in the northern Gulf Coast region was developed as a visual-analysis tool for the U.S. Geological Survey's 2002 assessment of undiscovered, technically recoverable oil and natural gas resources in the East Texas Basin and Louisiana-Mississippi Salt Basins Provinces. The Central Energy Resources Team of the U.S. Geological Survey has also developed an Internet Map Service to deliver the GIS data to the public. This mapping tool utilizes information from a database about the oil and natural gas endowment of the United States-including physical locations of geologic and geographic data-and converts the data into visual layers. Portrayal and analysis of geologic features on an interactive map provide an excellent tool for understanding domestic oil and gas resources for strategic planning, formulating economic and energy policies, evaluating lands under the purview of the Federal Government, and developing sound environmental policies. Assessment results can be viewed and analyzed or downloaded from the internet web site, http://energy.cr.usgs.gov/oilgas/noga/ .

  2. Mineralogy, petrology and whole-rock chemistry data compilation for selected samples of Yucca Mountain tuffs

    International Nuclear Information System (INIS)

    Connolly, J.R.

    1991-12-01

    Petrologic, bulk chemical, and mineralogic data are presented for 49 samples of tuffaceous rocks from core holes USW G-1 and UE-25a number-sign 1 at Yucca Mountain, Nevada. Included, in descending stratigraphic order, are 11 samples from the Topopah Spring Member of the Paintbrush Tuff, 12 samples from the Tuffaceous Beds of Calico Hills, 3 samples from the Prow Pass Member of the Crater Flat Tuff, 20 samples from the Bullfrog Member of the Crater Flat Tuff and 3 samples from the Tram Member of the Crater Flat Tuff. The suite of samples contains a wide variety of petrologic types, including zeolitized, glassy, and devitrified tuffs. Data vary considerably between groups of samples, and include thin section descriptions (some with modal analyses for which uncertainties are estimated), electron microprobe analyses of mineral phases and matrix, mineral identifications by X-ray diffraction, and major element analyses with uncertainty estimates

  3. Investigating combined influence of petrology and technological parameters on strength of porous coke body

    Energy Technology Data Exchange (ETDEWEB)

    Dinel' t, V.M.; Shkoller, M.B.; Stankevich, A.S.; Korchuganova, G.S.

    1983-09-01

    The VUKhIN branch in Kuznetsk investigated effects of coal petrology and coking conditions on structural strength of coke in blast furnaces. Structural strength of coke produced from black coal from the Kuzbass as well as structural strength of coke partially gasified by carbon dioxide under conditions similar to those in blast furnaces was investigated. Fourteen samples of coal mixtures from the Kuzbass were used. Regression analysis was applied. Equations for forecasting coke properties on the basis of coal petrology and selected parameters characterizing coking were derived. Analyses showed that coke structural strength was decisively influenced by coefficients which characterized the average reflectivity of vitrinite in a coal mixture and its average density. After partial coke gasification by carbon dioxide effects of coefficients which characterized coal mixture nonhomogeneity (fluctuations of vitrinite reflectivity) and coal mixture density increased. Increasing coal density partially compensated negative effects of fluctuations of vitrinite reflectivity on coke structural strength. (10 refs.) (In Russian)

  4. Mineralogy, petrology and geochemistry of carbonaceous chondritic clasts in the LEW 85300 polymict eucrite

    Science.gov (United States)

    Zolensky, M. E.; Hewins, R. H.; Mittlefehldt, D. W.; Lindstrom, M. M.; Xiao, X.; Lipschutz, M. E.

    1992-01-01

    We have performed a detailed petrologic and mineralogic study of two chondritic clasts from the polymict eucrite Lewis Cliff (LEW) 85300, and performed chemical analyses by INAA and RNAA on one of these. Petrologically, the clasts are identified and are composed of dispersed aggregates, chondrules, and chondrule fragments supported by matrix. The aggregates and chondrules are composed of olivine, orthopyroxene, plus some diopside. The matrix consists of fine-grained olivine, and lesser orthopyroxene and augite. Fine-grained saponite is common in the matrix. The bulk major composition of the clast studied by INAA and RNAA shows unusual abundance patterns for lithophile, siderophile and chalcophile elements but is basically chondritic. The INAA/RNAA data preclude assignment of the LEW 85300,15 clast to any commonly accepted group of carbonaceous chondrite.

  5. PETRO.CALC.PLOT, Microsoft Excel macros to aid petrologic interpretation

    Science.gov (United States)

    Sidder, G.B.

    1994-01-01

    PETRO.CALC.PLOT is a package of macros which normalizes whole-rock oxide data to 100%, calculates the cation percentages and molecular proportions used for normative mineral calculations, computes the apices for ternary diagrams, determines sums and ratios of specific elements of petrologic interest, and plots 33 X-Y graphs and five ternary diagrams. PETRO.CALC.PLOT also may be used to create other diagrams as desired by the user. The macros run in Microsoft Excel 3.0 and 4.0 for Macintosh computers and in Microsoft Excel 3.0 and 4.0 for Windows. Macros provided in PETRO.CALC.PLOT minimize repetition and time required to recalculate and plot whole-rock oxide data for petrologic analysis. ?? 1994.

  6. Geology and petrology of alkaline Massif from Ilha de Vitoria, Sao Paulo State

    International Nuclear Information System (INIS)

    Motoki, A.

    1986-01-01

    Geological and petrological studies of the Vitoria Island Alkaline Complex, State of Sao Paulo, have been carried out by means of photo interpretation; field work, thin section studies, whole-rock chemical analysis, x-ray diffractometry, EPMA mineral analysis, and K-Ar and Rb-Sr dating. Radiometric dating indicates a late Cretaceous age for the Vitoria Island Alkaline Complex, which is concordant with the ages of other neighbouring alkaline bodies. (author)

  7. The Run-up to Volcanic Eruption Unveiled by Forensic Petrology and Geophysical Observations

    Science.gov (United States)

    Rasmussen, D. J.; Plank, T. A.; Roman, D. C.

    2017-12-01

    Volcanoes often warn of impending eruptions. However, one of the greatest challenges in volcano research is translating precursory geophysical signals into physical magmatic processes. Petrology offers powerful tools to study eruption run-up that benefit from direct response to magmatic forcings. Developing these tools, and tying them to geophysical observations, will help us identify eruption triggers (e.g., magmatic recharge, gas build-up, tectonic events) and understand the significance of monitored signals of unrest. We present an overview of petrologic tools used for studying eruption run-up, highlighting results from our study of the 1999 eruption of Shishaldin volcano. Olivine crystals contain chemical gradients, the consequence of diffusion following magma mixing events, which is modeled to determine mixing timescales. Modeled timescales provide strong evidence for at least three mixing events, which were triggered by magmatic recharge. Petrologic barometers indicate these events occurred at very shallow depths (within the volcanic edifice). The first mixing event occurred nine months before eruption, which was signaled by a swarm of deep-long period earthquake. Minor recharge events followed over two months, which are indicated by a second deep-long period earthquake swarm and a change in the local stress orientation measured by shear-wave splitting. Following these events, the system was relatively quiet until a large mixing event occurred 45 days prior to eruption, which was heralded by a large earthquake (M5.2). Following this event, geophysical signals of unrest intensified and became continuous. The final mixing event, beginning roughly a week before eruption, represents the final perturbation to the system before eruption. Our findings point to a relatively long run-up, which was subtle at first and intensified several weeks before eruption. This study highlights the strong link between geophysical signals of volcanic unrest and magmatic events, and

  8. Mineralogy, Petrology, Chronology, and Exposure History of the Chelyabinsk Meteorite and Parent Body

    Science.gov (United States)

    Righter, K.; Abell, P.; Agresti, D.; Berger, E. L.; Burton, A. S.; Delaney, J. S.; Fries, M. D.; Gibson, E. K.; Harrington, R.; Herzog, G. F.; hide

    2015-01-01

    The Chelyabinsk meteorite fall on February 15, 2013 attracted much more attention worldwide than do most falls. A consortium led by JSC received 3 masses of Chelyabinsk (Chel-101, -102, -103) that were collected shortly after the fall and handled with care to minimize contamination. Initial studies were reported in 2013; we have studied these samples with a wide range of analytical techniques to better understand the mineralogy, petrology, chronology and exposure history of the Chelyabinsk parent body.

  9. Petrology and organic geochemistry of the lower Miocene lacustrine sediments (Most Basin, Eger Graben, Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Havelcová, Martina; Sýkorová, Ivana; Mach, K.; Trejtnarová, Hana; Blažek, Jaroslav

    2015-01-01

    Roč. 139, Special issue (2015), s. 26-39 ISSN 0166-5162 R&D Projects: GA ČR(CZ) GA13-18482S Institutional support: RVO:67985891 Keywords : Most Basin * Miocene * coal facies indices * coal petrology * organic geochemistry Subject RIV: DD - Geochemistry Impact factor: 3.294, year: 2015 http://www.sciencedirect.com/science/article/pii/S0166516214001529#

  10. Microchemistry, geochemistry and geochronology of the Lagoa Real Uranium Province (BA) magmatic association: petrological and evolutionary significance

    International Nuclear Information System (INIS)

    Amorim, Lucas Eustaquio Dias

    2016-01-01

    The Lagoa Real Uranium Province (PULR) is located in the center-south of the Bahia State, in the central part of Sao Francisco Craton and consists of an association of Paleoproterozoic meta-granites, alkali-gneiss, albitites, meta-leucodiorite and charnockites. This work has as objective the studies of the magmatic association, trying to understand its petrological and evolutionary meaning. For this purpose, representative bodies were sampled in order to develop unpublished studies of litogeochemistry, isotopes, geochronology and mineral chemistry. These analyzes were performed in: different preserved granitoid facies (Lagoa do Barro, Sao Timoteo, Juazeirinho and late pegmatitic phases), the meta-leucodiorites and charnockite. The data obtained using several modern methodologies, such as geochronology and mineral chemistry by LA-ICP-MS, provided results that allowed the characterization of two magmatic lithologies not described in the literature (Juazeirinho granite e late pegmatitic phases), and also a lithology preliminarily described (Lagoa do Barro granite). Moreover, these data contributed to elucidate the origin and meaning of the leucodiorite and charnoquito varieties, and made it possible to verify new compositional and mineral chemistry tendencies of Sao Timoteo granite. The data presented show that the studied granites were affected by albititization events (tardi or post-magmatic), which have different micro-chemical characteristics from the processes of albite formation related to the non-mineralized albitites bodies. Three albititization events were identified: a) An event that affected the granites characterized by the formation of albite with Rb and U, (b) Another event related to fluids associated with late pegmatitic bodies that formed albite with high levels of U, Rb and Ba, and partially affected the granites of the next pegmatoids portions; and (c) a final albititization event that caused the formation of the albite gneiss bodies, with albite

  11. Apollo 12 feldspathic basalts 12031, 12038, and 12072; petrology, comparison and interpretations

    International Nuclear Information System (INIS)

    Beaty, E.W.; Hill, S.M.R.; Albee, A.L.; Baldridge, W.S.

    1979-01-01

    Modal and chemical data indicate that 12072, 12038, and 12031, the Apollo 12 feldspathic basalts, form a well-defined group which cannot be related to the other Apollo 12 rock types. 12072 contains phenocrysts of olivine and pigeonite and microphenocrysts of Cr-spinel set in a fine-grained, variolitic groundmass. 12038 is a medium-grained, equigranular basalt with a texture indicating it was multiply saturated. 12031 is a coarse-grained rock with granular to graphic intergrowths of pyroxene and plagioclase; it was also multiply saturated. Petrologic observations, as well as the bulk chemistry, are consistent with the interpretation that 12031 could be derived from 12072 through fractionation of Cr-spinel, olivine, and pigeonite, the observed phenocryst assemblage. 12038, however, contains more pigeonite, less olivine, three times as much Ca-phosphate minerals, one-fifth as much troilite, and much more sodic plagioclase than 12072. These differences indicate that 12038 must have come from a separate igneous body. Consideration of the bulk compositions indicates that neither 12072 and 12031 nor 12038 could have been derived from the Apollo 12 olivine, pigeonite, or ilmenite basalts by crystal--liquid fractionation. The general petrologic similarities between 12072, 12031, and the other Apollo 12 basalts suggests that they were produced in either the same or similar source regions. 12038, however, is petrologically and chemically unique, and is probably exotic to the Apollo 12 landing site

  12. Petrological and geochemical characteristics of Shuixigou group in Yili basin

    International Nuclear Information System (INIS)

    Wang Jinping; Min Maozhong

    2003-01-01

    The Shuixigou Group, Lower-Middle Jurassic is the uranium-hosting formation of in-situ leachable sandstone-type uranium deposits in Yili basin. Rocks of the Shuixigou Group were extensively corroded during the diagenesis by the CO 2 -and organic acid-rich water derived from the organic matter existing in the strata. As a result, sandstones became loose and porous. Data of geochemical background such as uranium, organic carbon and major element contents in this paper are the achievement of authors. The results indicate that the distribution of uranium, organic matter and major elements is closely associated with the formation of epigenetic interlayer oxidation zone sandstone-type uranium deposits, and with the discrimination of ore-hosting and barren interlayer oxidation zones

  13. PROBLEMS AND METHODOLOGY OF THE PETROLOGIC ANALYSIS OF COAL FACIES.

    Science.gov (United States)

    Chao, Edward C.T.

    1983-01-01

    This condensed synthesis gives a broad outline of the methodology of coal facies analysis, procedures for constructing sedimentation and geochemical formation curves, and micro- and macrostratigraphic analysis. The hypothetical coal bed profile has a 3-fold cycle of material characteristics. Based on studies of other similar profiles of the same coal bed, and on field studies of the sedimentary rock types and their facies interpretation, one can assume that the 3-fold subdivision is of regional significance.

  14. New isotopic and field evidence for the ages and distribution of Archaean rocks in east Antarctica

    International Nuclear Information System (INIS)

    Kinny, P.D.; Delor, C.P.

    1990-01-01

    The Precambrian shield of East Antarctica is composed of a number of recognised Archaean cratonic nuclei surrounded by Proterozoic metamorphic complexes. Poor exposure, inaccessibility and the effects of multiple tectonothermal overprints combine to confound the knowledge of the early history of these terranes. Against this, it is shown how recent advances in zircon geochronology allied with new petrological, geochemical and field observations have resulted in major revisions to the chronostratigraphy of several key areas, including Napier Complex of Enderby Land, Vestfold Hills and Rauer Group. 11 refs

  15. Petrological, magnetic and chemical properties of basalt dredged from an abyssal hill in the North-east pacific

    Science.gov (United States)

    Luyendyk, B.P.; Engel, C.G.

    1969-01-01

    OVER the years, samples of basalt from the oceanic crust have been taken mainly from seamounts, fracture zones and ridge and rise crests1-6, and rarely from the vast fields of abyssal hills which cover a large part of the deep-sea floor. The basalt sampled from the deeper regions of the oceanic crust (for example, on fault scarps) is a distinct variety of tholeiitic basalt, while alkali basalt is restricted to the volcanic edifices4. Oceanic tholeiitic basalt differs from alkali basalt and continental tholeiite chiefly in having a relatively low percentage of K2O (0.2 weight per cent)4. Some authors have speculated that this type of tholeiitic basalt is the major extrusion from the upper mantle and constitutes the predominant rock type in the upper oceanic crust. ?? 1969 Nature Publishing Group.

  16. Petrology of blueschist facies metamorphic rocks of the Meliata Unit

    Directory of Open Access Journals (Sweden)

    Faryad Shah Wali

    1997-06-01

    Full Text Available Meliata blueschists originated from basalts, limestones, pelites, psammitic and amphibolite facies basement rocks. Compositionally, the metabasalts have a geochemical signature mostly indicative of a transitional arc-MORB origin, but some mafic rocks having affinity with within plate basalts also present. The mafic blueschists consist of blue amphibole, epidote and albite, rarely also garnet, Na-pyroxene and chloritoid. Apart from phengite and quartz the metapelites and metapsammites contain one or more of the minerals: chloritoid, paragonite, glaucophane, albite, chlorite, occasionally also Na-pyroxene and garnet. Amphibolite facies rocks contain relic garnet, plagioclase and hornblende, the latter two replaced by albite and blue amphibole, respectively. The zoning patterns of blue amphibole, garnet and chloritoid suggest their formation during prograde stage of metamorphism. P-T conditions of meta-morphism are estimated to be about 350-460 oC and 10-12 kbar.

  17. The origin and distribution of HAPs elements in relation to maceral composition of the A1 lignite bed (Paleocene, Calvert Bluff Formation, Wilcox Group), Calvert mine area, east-central Texas

    Science.gov (United States)

    Crowley, Sharon S.; Warwick, Peter D.; Ruppert, Leslie F.; Pontolillo, James

    1997-01-01

    The origin and distribution of twelve potentially Hazardous Air Pollutants (HAPs; As, Be, Cd, Cr, Co, Hg, Mn, Ni, Pb, Sb, Se, and U) identified in the 1990 Clean Air Act Amendments were examined in relation to the maceral composition of the A1 bed (Paleocene, Calvert Bluff Formation, Wilcox Group) of the Calvert mine in east-central Texas. The 3.2 m-thick A1 bed was divided into nine incremental channel samples (7 lignite samples and 2 shaley coal samples) on the basis of megascopic characteristics. Results indicate that As, Cd, Cr, Ni, Pb, Sb, and U are strongly correlated with ash yield and are enriched in the shaley coal samples. We infer that these elements are associated with inorganic constituents in the coal bed and may be derived from a penecontemporaneous stream channel located several kilometers southeast of the mining block. Of the HAPs elements studied, Mn and Hg are the most poorly correlated to ash yield. We infer an organic association for Mn; Hg may be associated with pyrite. The rest of the trace elements (Be, Co, and Se) are weakly correlated with ash yield. Further analytical work is necessary to determine the mode of occurrence for these elements. Overall, concentrations of the HAPs elements are generally similar to or less than those reported in previous studies of lignites of the Wilcox Group, east-central region, Texas. Petrographic analysis indicates the following ranges in composition for the seven lignite samples: liptinites (5–8%), huminites (88–95%), and inertinites (trace amounts to 7%). Samples from the middle portion of the A1 bed contain abundant crypto-eugelinite compared to the rest of the samples; this relationship suggests that the degradation of plant material was an important process during the development of the peat mire. With the exception of Hg and Mn, relatively low levels of the HAPs elements studied are found in the samples containing abundant crypto-eugelinite. We infer that the peat-forming environment for this

  18. Seismic, petrological and geodynamical constraints on thermal and compositional structure of the upper mantle: global thermochemical models

    DEFF Research Database (Denmark)

    Cammarano, Fabio; Tackley, Paul J.; Boschi, Lapo

    2011-01-01

    Mapping the thermal and compositional structure of the upper mantle requires a combined interpretation of geophysical and petrological observations. Based on current knowledge of material properties, we interpret available global seismic models for temperature assuming end-member compositional...... structures. In particular, we test the effects of modelling a depleted lithosphere, which accounts for petrological constraints on continents. Differences between seismicmodels translate into large temperature and density variations, respectively, up to 400K and 0.06 g cm-3 at 150 km depth. Introducing...... lateral compositional variations does not change significantly the thermal interpretation of seismic models, but gives a more realistic density structure. Modelling a petrological lithosphere gives cratonic temperatures at 150 km depth that are only 100 K hotter than those obtained assuming pyrolite...

  19. Research on petrologic, geochemical characteristics and genesis of volcanic rocks in Dachangsha basin

    International Nuclear Information System (INIS)

    Wei Sanyuan

    1999-01-01

    On the basis of research on petrologic, geochemical characteristics and isotope composition of volcanic rocks in Dachangsha basin, the author concludes that the volcanic rocks formed from magma of different genesis and depth are double-cycle effusive. It is proposed that the magma forming the intermediate-basic volcanics of the first cycle comes from the mixing of the partial melting of the deep crust and mantle, and the intermediate-acidic volcanics of the secondary cycle are derived from the remelting of the upper crust

  20. A-type granites from the Guéra Massif, Central Chad: Petrology, geochemistry, geochronology, and petrogenesis.

    Science.gov (United States)

    Pham, Ngoc Ha T.; Shellnutt, J. Gregory; Yeh, Meng-Wan; Lee, Tung-Yi

    2017-04-01

    The poorly studied Saharan Metacraton of North-Central Africa is located between the Arabian-Nubian Shield in the east, the Tuareg Shield in the west and the Central African Orogenic Belt in the south. The Saharan Metacraton is composed of Neoproterozoic juvenile crust and the relics of pre-Neoproterozoic components reactivated during the Pan-African Orogeny. The Republic of Chad, constrained within the Saharan Metacraton, comprises a Phanerozoic cover overlying Precambrian basement outcroppings in four distinct massifs: the Mayo Kebbi, Tibesti, Ouaddaï, and the Guéra. The Guéra massif is the least studied of the four massifs but it likely preserves structures that were formed during the collision between Congo Craton and Saharan Metacraton. The Guéra Massif is composed of mostly granitic rocks. The granitoids have petrologic features that are consistent with A-type granite, such as micrographic intergrowth of sodic and potassic feldspar, the presence of sodic- and iron-rich amphibole, and iron-rich biotite. Compositionally, the granitic rocks of the Guéra Massif have high silica (SiO2 ≥ 68.9 wt.%) content and are metaluminous to marginally peraluminous. The rocks are classified as ferroan calc-alkalic to alkali-calcic with moderately high to very high Fe* ratios. The first zircon U/Pb geochronology of the silicic rocks from the Guéra Massif yielded three main age groups: 590 Ma, 570 Ma, 560 Ma, while a single gabbro yielded an intermediate age ( 580 Ma). A weakly foliated biotite granite yielded two populations, in which the emplacement age is interpreted to be 590 ± 10 Ma, whereas the younger age (550 ± 11 Ma) is considered to be a deformation age. Furthermore, inherited Meso- to Paleoproterozoic zircons are found in this sample. The geochemical and geochronology data indicate that there is a temporal evolution in the composition of rocks with the old, high Mg# granitoids shifting to young, low Mg# granitoids. This reveals that the A-type granites in

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

    Science.gov (United States)

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

    2017-12-01

    fate of sulfide during decompression melting of peridotite - implications for sulfur inventory of the MORB-source depleted upper mantle. Earth and Planetary Science Letters 459, 183-195 (2017). 5. Sakaia, R., Nagaharaa, H., Ozawaa, K. & Tachibanab, S. Composition of the lunar magma ocean constrained by the conditions for the crust formation. Icarus 229, 45-56 (2014).

  2. The Private Lives of Minerals: Social Network Analysis Applied to Mineralogy and Petrology

    Science.gov (United States)

    Hazen, R. M.; Morrison, S. M.; Fox, P. A.; Golden, J. J.; Downs, R. T.; Eleish, A.; Prabhu, A.; Li, C.; Liu, C.

    2016-12-01

    Comprehensive databases of mineral species (rruff.info/ima) and their geographic localities and co-existing mineral assemblages (mindat.org) reveal patterns of mineral association and distribution that mimic social networks, as commonly applied to such varied topics as social media interactions, the spread of disease, terrorism networks, and research collaborations. Applying social network analysis (SNA) to common assemblages of rock-forming igneous and regional metamorphic mineral species, we find patterns of cohesion, segregation, density, and cliques that are similar to those of human social networks. These patterns highlight classic trends in lithologic evolution and are illustrated with sociograms, in which mineral species are the "nodes" and co-existing species form "links." Filters based on chemistry, age, structural group, and other parameters highlight visually both familiar and new aspects of mineralogy and petrology. We quantify sociograms with SNA metrics, including connectivity (based on the frequency of co-occurrence of mineral pairs), homophily (the extent to which co-existing mineral species share compositional and other characteristics), network closure (based on the degree of network interconnectivity), and segmentation (as revealed by isolated "cliques" of mineral species). Exploitation of large and growing mineral data resources with SNA offers promising avenues for discovering previously hidden trends in mineral diversity-distribution systematics, as well as providing new pedagogical approaches to teaching mineralogy and petrology.

  3. Petrological Geodynamics of Mantle Melting I. AlphaMELTS + Multiphase Flow: Dynamic Equilibrium Melting, Method and Results

    Directory of Open Access Journals (Sweden)

    Massimiliano Tirone

    2017-10-01

    with time, the melt and solid composition approach the composition that is found from a dynamic batch melting model which assumes the velocities of melt and residual solid to be the same. Time dependent melt fluctuations can be observed under certain conditions. In this case the composition of the melt that reaches the top side of the model (exit point may vary to some extent. A consistent result of the model under various conditions is that the volume of the first melt that arrives at the exit point is substantially larger than any later melt output. The analogy with large magma emplacements associated to continental break-up or formation of oceanic plateaus seems to suggest that these events are the direct consequence of a dynamic two-phase flow process. Even though chemical equilibrium between melt and the residual solid is imposed locally in space, bulk composition of the whole system (solid+melt varies with depth and may also vary with time, mainly as the result of the changes of the melt abundance. Potential factors that can influence the melting process such as bulk composition, temperature and mantle upwelling velocity at the top boundary (passive flow or bottom boundary (active flow should be addressed more systematically before the DEM model in this study and the dynamic fractional melting (DFM model that will be introduced in the second installment can be applied to interpret real petrological data. Complete data files of most of the simulations and four animations are available following the data repository link provided in the Supplementary Material.

  4. West and East

    Directory of Open Access Journals (Sweden)

    Alexander Rappaport

    2017-12-01

    Full Text Available The topic “West-East” has a clear cultural and historical meaning. Orthodox temples face East. The way from West to East and from East to West is tens of thousands of kilometers long and has a special meaning. It differs from the way from North to South: the horizontal axes connect regions, while the vertical axis (Earth-Sky connects the worlds. The expansion of Eurasian tribes occurred along the East-West axis – the world horizontal way. Today the cultural memory of people in the East and West finds itself in the theatre of new dramas of existence and new forces. With the advances in electronic technologies, the world movements seem to have sunk in the depth of the chthonian past to come up anew to the surface of fantastic speeds and momentary connections. A new type of planetary landscape-space relation appears, giving no place for West and East.

  5. Petrology, isotopic and fluid inclusion studies of eclogites from Sujiahe, NW Dabie Shan (China), July 1 2002

    NARCIS (Netherlands)

    Fu, B.; Zheng, Y.-F.; Touret, J.L.R.

    2002-01-01

    In addition to the Triassic Hong'an low-T-high-P eclogite and the Xinxian coesite-bearing kyanite-glaucophane eclogite, Silurian coesite-free amphibole eclogites occur in the Sujiahe region, NW Dabie Shan of central China. A comprehensive study of petrology, Nd-Sr, O-H isotopes and fluid inclusions

  6. JPRS Report, East Europe

    National Research Council Canada - National Science Library

    1988-01-01

    Partial Contents: East Europe, Party Activities, Socialist Party, Freedom Fighters, Education, Youth Training, Historian, Death Penalty, Peace Making Duties, Socialism, Communism, Economics, Restructuring...

  7. Teaching Mineralogy, Petrology and Geochemistry in the 21st Century: Instructional Resources for Geoscience Faculty

    Science.gov (United States)

    Mogk, D. W.; Beane, R. J.; Whitney, D. L.; Nicolaysen, K. E.; Panero, W. R.; Peck, W. H.

    2011-12-01

    Mineralogy, petrology and geochemistry (MPG) are pillars of the geoscience curriculum because of their relevance in interpreting Earth history and processes, application to geo-hazards, resources, and environmental issues, and contributions to emerging fields such as geology and human health. To keep faculty current in scientific advances in these fields, and in modern instructional methods, the On the Cutting Edge program convened a workshop at the University of Minnesota in August, 2011. This workshop builds on the previous 15 year's work that has been focused on identifying, aggregating, and developing high-quality collections of teaching activities and related resources, and in building a community of scholars in support of excellence in instruction in MPG courses. The goals of the workshop were to: a) develop an integrated, comprehensive and reviewed curriculum for MPG courses, and to seek ways to make connections with the larger geoscience curriculum; b) to explore emerging topics in MPG such as geobiology and climate change; c) demonstrate effective methods in teaching MPG in the context of Earth system science; d) share effective teaching activities and strategies for the classroom, laboratory and field including advances in pedagogy, assessments and research on learning; e) keep faculty current on recent advances in mineralogy, petrology and geochemistry research and to apply these findings to our teaching; f) explore and utilize current societal and global issues that intersect mineralogy, petrology and geochemistry to heighten the relevancy of course content for students; and h) meet colleagues and foster future teaching and research collaborations. A significant outcome of this workshop is a peer reviewed of collection of 300+ existing teaching activities, and a gap analysis to identify teaching activities needed to make these collections comprehensive and coherent. In addition, a series of thematic collections were developed to assist high priority

  8. Geology, Alteration, Mineralization, Geochemistry and Petrology of intrusive units in the Shah Soltan Ali prospect area (Southwest of Birjand, South Khorasan province

    Directory of Open Access Journals (Sweden)

    Samaneh Nadermezerji

    2017-07-01

    Full Text Available Introduction The Shah Soltan Ali area is located 85 km southwest of Birjand in the South Khorasan province. This area is part of the Tertiary volcanic-plutonic rocks in the east of the Lut block. The Lut block is bounded to the east by the Nehbandan and associated faults, to the north by the Doruneh and related faults (Sabzevar zone, to the south by the Makran arc and Bazman volcanic complex and to the west by the Nayband Fault. The Lut block is the main metallogenic province in the east of Iran (Karimpour et al., 2012, that comprises of numerous porphyry Cu and Cu–Au deposits, low and high sulfidation epithermal Au deposits, iron oxide deposits, base-metal deposits and Cu–Pb–Zn vein-type deposits. The geology of Shah Soltan Ali area is dominated by volcanic rocks, comprised of andesite and basalt, which are intruded by subvolanic units such as monzonite porphyry, monzodiorite porphyry and diorite porphyry. Materials and methods 1. 170 thin sections of the rock samples as well as 25 polished and thin polished sections were prepared for petrography, alteration and mineralization. 2. Twenty five samples were analyzed for Cu, Pb, Zn, Sb, Mo and As elements by the Aqua regia method in the Zarazama laboratory in Tehran, Iran. 3. Nine samples were analyzed for trace elements [including rare earth elements (REEs]. As a result of these analyses, trace elements and REE were determined by inductively coupled plasma mass spectrometry (ICP-MS in the ACME Analytical Laboratories (Vancouver Ltd., Canada. 4. Ten samples were analyzed for major elements by wavelength dispersive X-ray fluorescence spectrometry in the East Amethyst laboratory in Mashhad, Iran. 5. Five samples were analyzed for Firre Assay analysis in the Zarazma Laboratory in Tehran, Iran. 6. The results of XRD analysis were used for 4 samples. Discussion and results Petrographic studies indicate that subvolcanic rocks consist of diorite porphyry, monzonite porphyry and monzodiorite

  9. East African Medical Journal

    African Journals Online (AJOL)

    The East African Medical Journal is intended for publication of papers on ... research on problems relevant to East Africa and other African countries will receive special ... Analysis of survival patterns of TB‐HIV co‐infected patients in relation to ...

  10. Middle East Respiratory Syndrome

    Centers for Disease Control (CDC) Podcasts

    2014-07-07

    This podcast discusses Middle East Respiratory Syndrome, or MERS, a viral respiratory illness caused by Middle East Respiratory Syndrome Coronavirus—MERS-CoV.  Created: 7/7/2014 by National Center for Immunization and Respiratory Diseases (NCIRD).   Date Released: 7/7/2014.

  11. Middle East - future perspectives

    International Nuclear Information System (INIS)

    Lior, Y.

    1997-01-01

    Facts concerning the basic features of Tlatelolco Treaty are discussed in comparison with the Middle East situation which is described as a special case. Countries in the Middle East should attain political, social and ideological maturity necessary for the adoption of negotiating strategies suitable for this particular region

  12. Petrology and geochemistry of greywackes of Middle Aravalli supergroup, NW India: evidence for active margin processes

    International Nuclear Information System (INIS)

    Absar, Nurul; Sreenivas, B.

    2013-01-01

    Aravalli Mountain Belt (AMB) of Northwestern, India represents one of the major Proterozoic accretionary orogens of the world, preserving two Wilson cycles; viz. Paleoproterozoic Aravalli Supergroup and Mesoproterozoic Delhi Supergroup. Although two gross Wilson cycles involving opening and closing of Paleoproterozoic Aravalli ocean and Mesoproterozoic Delhi ocean are recognized, the finer details of the evolution of the orogen are still poorly understood. We have carried out geochemical and petrological study of the well-preserved greywacke horizon of the 'Middle Aravalli Supergroup' in order to place constraints on early evolution of the Aravalli basin. These greywackes are enriched in Fe, Mg and K; and depleted in Na in comparison to normal greywackes and can be classified as ferroan potassic sandstone. Petrographic examination indicate that the greywacke samples contain about 30 to 50% matrix that is mainly composed of biotite/chlorite and interspersed with fine Fe-Ti rich opaque mineral phases

  13. Musa massif: mapping, petrology and petrochemical, Rio Maria, SE from Para State

    International Nuclear Information System (INIS)

    Gastal, M.C.P.

    1987-01-01

    The petrological, geochemical and geochronological studies allow some insight on the genesis and evolution of the Musa Massif. The different facies of the granitic body are cogenetic, although each of these facies presents some peculiarities in its genesis and evolution. These data suggests that the granite magma evolution was complex or, alternatively, that the facies were generated by liquids derived from different sources. A model of magmatic emplacement, genesis and differentiation is proposed and discussed. The granitic facies show a calc-alkaline compositions, exhibiting strong analogies with cordilleran granites or magnetite granites. An age of 1692 +- 11 Ma (Rb/Sr) with IR of 0,70777 +- 0,00023 was obtained for different facies of Massif. A preliminary attempt to individualize geochronology the principal facies was done and showed that there is a coincidence between the ages and the emplacement sequence of these facies of the pluton. (author)

  14. Petrology and geochemistry of Late Proterozoic hornblende gabbros from southeast of Fariman, Khorasan Razavi province, Iran

    Directory of Open Access Journals (Sweden)

    Seyed Masoud Homam

    2015-04-01

    Full Text Available Introduction Hornblende-bearing gabbroic rocks are quite common in subduction-related magmatic suites and considered to represent magmatic differentiation process in arc magmas (Heliker, 1995; Hickey-Vargas et al., 1995; Mandal and Ray, 2012. The presence of hornblende as an important mineral phase in gabbroic rocks of subduction zone has been considered either as an early crystallizing mineral from water-bearing mafic magmas (Beard and Borgia 1989; Mandal and Ray, 2012 or as a product of reaction of early crystallized minerals (olivine, pyroxene and plagioclase and water-rich evolved melt/aqueous fluid (Costa et al., 2002; Mandal and Ray, 2012. The careful study of petrology and geochemistry of hornblende-bearing gabbroic rocks from Chahak area, of Neoproterozoic age, can provide important information about their petrogenesis. Because of the special characteristics of Chahak hornblende gabbros according to their age and their situation in the main structural units of Iran, their study can present critical keys for the knowledge of geological history of Iran specially central Iran zone. Material and Methods This study carried out in two parts including field and laboratory works. Sampling and structural studies were carried out during field work. Geological map for the study area was also prepared. 65 thin and polished thin sections for petrographical purpose were studied. Major oxides, rare earth elements and trace elements were analyzed for 4 samples (92P-1, 92P-3, B1and B6 from hornblende gabbros on the basis of 4AB1 method using ICP-MS of ACME Laboratory from Canada. In addition, major oxides of three hornblende gabbro samples (89P-62, 89P-59 and 89P-46 were used from Partovifar (Partovifar, 2012. Results and discussion Fariman metamorphic terrains, of Proterozoic age, consist of metamorphosed sedimentary and igneous (plutonic and volcanic rocks. Hornblende gabbros of the study area include plagioclase, hornblende, biotite pyroxene and

  15. A re-evaluation of palaeoclimatic conditions during the Pleistocene and Holocene from the western continental shelf of India - Evidences from the petrology of the limestones

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.; Nair, R.R.

    and 150 m water depth were studied for their petrology and to evaluate the palaeoclimatic conditions during Quaternary. The limestones characteristic of abundant microspar and pseudospar are found at water depths 65 and 95 m, respectively...

  16. The mineralogy and petrology of I-type cosmic spherules: Implications for their sources, origins and identification in sedimentary rocks

    Science.gov (United States)

    Genge, Matthew J.; Davies, Bridie; Suttle, Martin D.; van Ginneken, Matthias; Tomkins, Andrew G.

    2017-12-01

    I-type cosmic spherules are micrometeorites that formed by melting during atmospheric entry and consist mainly of iron oxides and FeNi metal. I-types are important because they can readily be recovered from sedimentary rocks allowing study of solar system events over geological time. We report the results of a study of the mineralogy and petrology of 88 I-type cosmic spherules recovered from Antarctica in order to evaluate how they formed and evolved during atmospheric entry, to constrain the nature of their precursors and to establish rigorous criteria by which they may be conclusively identified within sediments and sedimentary rocks. Two textural types of I-type cosmic spherule are recognised: (1) metal bead-bearing (MET) spherules dominated by Ni-poor (100 and suggest that metal from H-group ordinary, CM, CR and iron meteorites may form the majority of particles. Oxidation during entry heating increases in the series MET 80 wt% Ni comprising a particle mass fraction of exchange of Ni between wüstite and metal, and magnetite and wüstite are suggested as proxies for the rate of oxidation and cooling rate respectively. Variations in magnetite and wüstite crystal sizes are also suggested to relate to cooling rate allowing relative entry angle of particles to be evaluated. The formation of secondary metal in the form of sub-micron Ni-rich or Pt-group nuggets and as symplectite with magnetite was also identified and suggested to occur largely due to the exsolution of metallic alloys during decomposition of non-stoichiometric wüstite. Weathering is restricted to replacement of metal by iron hydroxides. The following criteria are recommended for the conclusive identification of I-type spherules within sediments and sedimentary rocks: (i) spherical particle morphologies, (ii) dendritic crystal morphologies, (iii) the presence of wüstite and magnetite, (iv) Ni-bearing wüstite and magnetite, and (v) the presence of relict FeNi metal.

  17. The lithospheric structure beneath Ireland and surrounding areas from integrated geophysical-petrological modelling of magnetic and other geophysical data

    Science.gov (United States)

    Baykiev, E.; Guerri, M.; Fullea, J.

    2017-12-01

    The availability of unprecedented resolution aeromagnetic data in Ireland (Tellus project, http://www.tellus.ie/) in conjunction with new satellite magnetic data (e.g., ESÁs Swarm mission) has opened the possibility of detailed modelling of the Irish subsurface magnetic structure. A detailed knowledge of the magnetic characteristics (susceptibility, magnetite content) of the crust is relevant for a number of purposes, including geological mapping and mineral and geothermal energy prospection. In this work we model the magnetic structure of Ireland and surrounding areas using primarily aeromagnetic and satellite observations but also other geophysical data sets. To this aim we use a geophysical-petrological modelling tool (LitMod) in which key properties of rocks (i.e., density, electrical conductivity and seismic velocities) that can be inferred from geophysical data (gravity, seismic, EM) are self consistently determined based on the thermochemical conditions (using the software Perple_X). In contrast to the mantle, where thermodynamic equilibrium is prevalent, in the crust metastable conditions are dominant, i.e. rock properties may not be representative of the current, in situ, temperature and pressure conditions. Instead, the rock properties inferred from geophysical data may be reflecting the mineralogy stable at rock formation conditions. In addition, temperature plays a major role in the distribution of the long wavelength crustal magnetic anomalies. Magnetite retains its magnetic properties below its Curie temperature (585 ºC) and the depth of Curie's isotherm provides an estimate of the thickness of the magnetic crust. Hence, a precise knowledge of the crustal geotherm is required to consistently model crustal magnetic anomalies. In this work LitMod has been modified to account for metastable crustal lithology, to predict susceptibility in the areas below Curie's temperature, and to compute magnetic anomalies based on a magnetic tesseroid approach. The

  18. Mid-Cretaceous aeolian desert systems in the Yunlong area of the Lanping Basin, China: Implications for palaeoatmosphere dynamics and paleoclimatic change in East Asia

    Science.gov (United States)

    Li, Gaojie; Wu, Chihua; Rodríguez-López, Juan Pedro; Yi, Haisheng; Xia, Guoqing; Wagreich, Michael

    2018-02-01

    The mid-Cretaceous constitutes a period of worldwide atmospheric and oceanic change associated with slower thermohaline circulation and ocean anoxic events, possible polar glaciations and by a changing climate pattern becoming controlled by a zonal planetary wind system and an equatorial humid belt. During the mid-Cretaceous, the subtropical high-pressure arid climate belt of the planetary wind system controlled the palaeolatitude distribution of humid belts in Asia as well as the spatial distribution of rain belts over the massive continental blocks at mid-low latitudes in the southern and northern hemispheres. Additionally, the orographic effect of the Andean-type active continental margin in East Asia hindered the transportation of ocean moisture to inland regions. With rising temperatures and palaeoatmospheric conditions dominated by high pressure systems, desert climate environments expanded at the inland areas of East Asia including those accumulated in the mid-Cretaceous of the Simao Basin, the Sichuan Basin, and the Thailand's Khorat Basin, and leading the Late Cretaceous erg systems in the Xinjiang Basin and Jianghan Basin. This manuscript presents evidences that allow to reinterpret previously considered water-laid sediments to be accumulated as windblown deposits forming part of extensive erg (sandy desert) systems. Using a multidisciplinary approach including petrological, sedimentological and architectural observations, the mid-Cretaceous (Albian-Turonian) Nanxin Formation from the Yunlong region of Lanping Basin, formerly considered to aqueous deposits is here interpreted as representing aeolian deposits, showing local aeolian-fluvial interaction deposits. The palaeowind directions obtained from the analysis of aeolian dune cross-beddings indicates that inland deserts were compatible with a high-pressure cell (HPC) existing in the mid-low latitudes of East Asia during the mid-Cretaceous. Compared with the Early Cretaceous, the mid-Cretaceous had

  19. Stratigraphy, sedimentology and petrology of neogene rocks in the Deschutes Basin, Central Oregon: a record of continental-margin volcanism and its influence on fluvial sedimentation in an arc-adjacent basin

    International Nuclear Information System (INIS)

    Smith, G.A.

    1986-07-01

    Neogene rocks of the Deschutes basin include the middle Miocene Columbia River Basalt Group and Simtustus Formation, and late Miocene to early Pliocene Deschutes Formation. Assignment of Prineville chemical-type flows to the Grande Ronde Basalt of the Columbia River Basalt Group is based on correlation of these lavas from their type area through the Deschutes basin and onto the Columbia Plateau, where they have been previously mapped as Grande Ronde Basalt. Simtustus Formation is a newly defined unit intercalated with and conformable upon these basalts, and is unconformably overlain by Deschutes Formation. Burial of mature topography by middle Miocene basalts raised local base levels and initiated aggradation by low-gradient streams within the basin represented by the tuffaceous sandstones and mudstones of the Simtustus Formation. These sediments are enriched in pyroclastic constituents relative to contemporaneous Western Cascades volcanics, reflecting preferential incorporation of easily eroded and more widespread pyroclastic debris in distal sedimentary sequences compared to epiclastic contributions from lavas. The abundance of basalts, combined with the paucity of hydrous minerals and FeO and TiO 2 enrichment in intermediate lavas, characterizes early High Cascade volcanics as atypical for convergent-margin arcs. These petrologic characteristics are consistent with high-level fractionation in an extensional regime. Extension culminated in the development of an intra-arc graben, which ended Deschutes Formation deposition by structurally isolating the basin from the High Cascade source area

  20. EAST AFRICAN MEDICAL JOURNAL

    African Journals Online (AJOL)

    2003-11-11

    Nov 11, 2003 ... East African Medical Journal Vol. ... Lecturer/Consultant Surgeon, Paediatric Surgery Unit, Department of Surgery, College of Medical Sciences, University of Calabar, .... mind and the results obtained were however satisfying.

  1. Fluxus East / Petra Stegmann

    Index Scriptorium Estoniae

    Stegmann, Petra

    2008-01-01

    Näitusest "Fluxus East" Kumu Kunstimuuseumis. Fluxuse liikumisest leedu kunstniku George Maciunase (1931-1978) eestvedamisel. Liikumise ilmingutest Eestis (happeningid, muusikaaktsioonid, visuaalne poeesia, mail art). Kuraator Petra Stegmann, kujundaja Andrea Pichl

  2. Leukaemia in East Suffolk

    International Nuclear Information System (INIS)

    Bush, M.F.H.

    1983-09-01

    An investigation was conducted by the East Suffolk Health Authority to determine whether there were any geographical variations in the incidence of leukaemia over the last fifteen years in East Suffolk suggesting an environmental hazard, e.g. Sizewell Power Station. No areas were found to have a statistically significant increased incidence of leukaemia cases although there did appear to be a cluster of cases in the Leiston area. (U.K.)

  3. Estimation of Water Within the Lithospheric Mantle of Central Tibet from Petrological-Geophysical Investigations

    Science.gov (United States)

    Vozar, J.; Fullea, J.; Jones, A. G.

    2013-12-01

    Investigations of the lithosphere and sub-lithospheric upper mantle by integrated petrological-geophysical modeling of magnetotelluric (MT) and seismic surface-wave data, which are differently sensitive to temperature and composition, allows us to reduce the uncertainties associated with modeling these two data sets independently, as commonly undertaken. We use selected INDEPTH MT data, which have appropriate dimensionality and large penetration depths, across central Tibet for 1D modeling. Our deep resistivity models from the data can be classified into two different and distinct groups: (i) the Lhasa Terrane and (ii) the Qiangtang Terrane. For the Lhasa Terrane group, the models show the existence of upper mantle conductive layer localized at depths of 200 km, whereas for the Qiangtang Terrane, this conductive layer is shallower at depths of 120 km. We perform the integrated geophysical-petrological modeling of the MT and surface-wave data using the software package LitMod. The program facilitates definition of realistic temperature and pressure distributions within the upper mantle for given thermal structure and oxide chemistry in the CFMAS system. This allows us to define a bulk geoelectric and seismic model of the upper mantle based on laboratory and xenolith data for the most relevant mantle minerals, and to compute synthetic geophysical observables. Our results suggest an 80-120 km-thick, dry lithosphere in the central part of the Qiangtang Terrane. In contrast, in the central Lhasa Terrane the predicted MT responses are too resistive for a dry lithosphere regardless its thickness; according to seismic and topography data the expected lithospheric thickness is about 200 km. The presence of small amounts of water significantly decreases the electrical resistivity of mantle rocks and is required to fit the MT responses. We test the hypothesis of small amounts of water (ppm scale) in the nominally anhydrous minerals of the lithospheric mantle. Such a small

  4. Geology, mineralization, geochemistry and petrology of intrusions in the Kuh Zar Au-Cu deposit, Damghan

    Directory of Open Access Journals (Sweden)

    Payam Roohbakhsh

    2018-04-01

    Full Text Available Introduction Kuh Zar Au-Cu deposit is located in the central part of the Torud-Chah Shirin Volcanic-Plutonic Belt, 100 km southeast of the city of Damghan. Mineralization including quartz-base metal veins are common throughout this Cenozoic volcano-plutonic belt (Liaghat et al., 2008; Mehrabi and Ghasemi Siani, 2010. The major part of the study area is covered with Cenozoic pyroclastic and volcanic rocks that are intruded by subvolcanic rocks. This paper aims to study the geological, geochemical and petrogenesis of the area using exploration keys for new mineral deposits in the Torud-Chah Shirin zone. Materials and methods To better understand the geological units and identify the alteration zones of the area, 200 rock samples were collected from the field and 132 thin sections with 15 polished thin sections were prepared for petrography and mineralization studies. Ten samples of intrusions with the least alteration were analyzed using the XRF at the East Amethyst Laboratory in Mashhad, Iran. These samples were also analyzed for trace and rare earth elements using ICP-MS, following a lithium metaborate/tetraborate fusion in the Acme Analytical Laboratories Ltd, Vancouver, Canada. 137 geochemistry samples were prepared by the chip composite method of alteration and mineralization zones and were analyzed in the Acme laboratory by Aqua Regia AQ250. Results The geology of the area consists of pyroclastic (crystal tuff and volcanic rocks with andesite and latite composition, which were intruded by subvolcanic intrusive rocks with porphyritic texture and monzonitic composition. Monzonite rocks were intruded by younger subvolcanic units with dioritic composition. The intrusion of monzonitic pluton and stocks led to the formation of QSP, propylitic, carbonate and silicification-tourmaline broad alteration zones in the area. Monzonite rocks accompanied with disseminated mineralization of about 1 to 10% of pyrite and these sulfides have been converted to

  5. Petrologic and geochemical characterization and mineralization of the metavolcanic rocks of the Heib Formation, Kid Metamorphic Complex, Sinai, Egypt

    Directory of Open Access Journals (Sweden)

    Ibrahim H. Khalifa

    2011-07-01

    Full Text Available Metavolcanic rocks hosting base metal sulphide mineralization, and belonging to the Kid Metamorphic Complex, are exposed in the Samra-Tarr area, Southern Sinai. The rocks consist of slightly metamorphosed varicolored porphyritic lavas of rhyolite-to-andesite composition, and their equivalent pyroclastics. Geochemically, these metavolcanics are classified as high-K calc-alkaline, metaluminous andesites, trachyandesites, dacites, and rhyolites. The geochemical characteristics of these metavolcanics strongly point to their derivation from continental crust in an active continental margin. The sulphide mineralization in these metavolcanics occurs in two major ore zones, and is represented by four distinct styles of mineralization. The mineralization occurs either as low-grade disseminations or as small massive pockets. The associated hydrothermal alterations include carbonatization, silicification, sericitization and argillic alterations. The base metal sulphide mineralization is epigenetic and was formed by hydrothermal solutions associated with subduction-related volcanic activity.

  6. Petrology and geochemistry of the ~2.9 Ga Itilliarsuk banded iron formation and associated supracrustal rocks, West Greenland

    DEFF Research Database (Denmark)

    Haugaard, Rasmus; Frei, Robert; Stendal, Henrik

    2013-01-01

    unconformably on a basement of tonalite–trondhjemite–granodiorite (TTG) lithologies. Felsic metagreywackes, meta-semipelites and thinly bedded ferruginous shales were identified intercalated with the Itilliarsuk BIF. Other associated rocks include metapelites, acidic metavolcanics and metagabbroic sills.......29. The associated supracrustal rocks in the study area have significantly higher, positive ɛNd(i) values. The 143Nd/144Nd in the Itilliarsuk BIF, therefore, contrasts world BIFs by exhibiting radiogenic, positive ɛNd(i) values in shallow seawaters where the REY's were controlled by a local, depleted continental...... crust, whereas the negative ɛNd(i) values found in the iron-rich layers suggest that the submarine hydrothermal source was influenced by an enriched mantle, possibly an older subcontinental lithospheric segment. The felsic metagreywackes are immature, first-cycle (SiO2/Al2O3 ∼ 4.4, [La/Yb >> 1]CHON...

  7. East Greenland Caledonides: stratigraphy, structure and geochronology: Lower Palaeozoic stratigraphy of the East Greenland Caledonides

    Directory of Open Access Journals (Sweden)

    Smith, M. Paul

    2004-12-01

    Full Text Available The Lower Palaeozoic stratigraphy of the East Greenland Caledonides, from the fjord region of North-East Greenland northwards to Kronprins Christian Land, is reviewed and a number of new lithostratigraphical units are proposed. The Slottet Formation (new is a Lower Cambrian quartzite unit, containing Skolithos burrows, that is present in the Målebjerg and Eleonore Sø tectonic windows, in the nunatak region of North-East Greenland. The unit is the source of common and often-reported glacial erratic boulders containing Skolithos that are distributed throughout the fjord region. The Målebjerg Formation (new overlies the Slottet Formation in the tectonic windows, and comprises limestones and dolostones of assumed Cambrian–Ordovician age. The Lower Palaeozoic succession of the fjord region of East Greenland (dominantly limestones and dolostones is formally placed in the Kong Oscar Fjord Group (new. Amendments are proposed for several existing units in the Kronprins Christian Land and Lambert Land areas, where they occur in autochthonous, parautochthonous and allochthonous settings.

  8. Geochemistry and petrology of selected coal samples from Sumatra, Kalimantan, Sulawesi, and Papua, Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Belkin, Harvey E.; Tewalt, Susan J. [U.S. Geological Survey, 956 National Center, Reston, VA 20192 (United States); Hower, James C. [University of Kentucky Center for Applied Energy Research, 2540 Research Park Drive, Lexington, KY 40511 (United States); Stucker, J.D. [University of Kentucky Center for Applied Energy Research, 2540 Research Park Drive, Lexington, KY 40511 (United States)]|[University of Kentucky Department of Earth and Environmental Sciences, Lexington, KY 40506 (United States); O' Keefe, J.M.K. [Morehead State University, Department of Physical Science, Morehead, KY 40351 (United States)

    2009-01-31

    Indonesia has become the world's largest exporter of thermal coal and is a major supplier to the Asian coal market, particularly as the People's Republic of China is now (2007) and perhaps may remain a net importer of coal. Indonesia has had a long history of coal production, mainly in Sumatra and Kalimantan, but only in the last two decades have government and commercial forces resulted in a remarkable coal boom. A recent assessment of Indonesian coal-bed methane (CBM) potential has motivated active CBM exploration. Most of the coal is Paleogene and Neogene, low to moderate rank and has low ash yield and sulfur (generally < 10 and < 1 wt.%, respectively). Active tectonic and igneous activity has resulted in significant rank increase in some coal basins. Eight coal samples are described that represent the major export and/or resource potential of Sumatra, Kalimantan, Sulawesi, and Papua. Detailed geochemistry, including proximate and ultimate analysis, sulfur forms, and major, minor, and trace element determinations are presented. Organic petrology and vitrinite reflectance data reflect various precursor flora assemblages and rank variations, including sample composites from active igneous and tectonic areas. A comparison of Hazardous Air Pollutants (HAPs) elements abundance with world and US averages show that the Indonesian coals have low combustion pollution potential. (author)

  9. Petrology of Ortsog-Uul peridotite-gabbro massif in Western Mongolia

    Science.gov (United States)

    Shapovalova, M.; Tolstykh, N.; Shelepaev, R.; Cherdantseva, M.

    2017-12-01

    The Ortsog-Uul mafic-ultramafic massif of Western Mongolia is located in a tectonic block with overturned bedding. The massif hosts two intrusions: a rhythmically-layered peridotite-gabbro association (Intrusion 1) and massive Bt-bearing amphibole-olivine gabbro (Intrusion 2). Intrusions 1 and 2 have different petrology features. Early Intrusion 1 (278±2.5Ma) is characterized by lower concentrations of alkalis, titanium and phosphorus than late Intrusion 2 (272±2Ma). The chondrite-normalized REE and primitive mantle-normalized rare elements patterns of Ortsog-Uul intrusions have similar curves of elements distribution. However, Intrusion 2 is characterized higher contents of REE and rare elements. High concentrations of incompatible elements are indicative of strong fractionation process. It has been suggested that Intrusions 1 and 2 derived from compositionally different parental melts. Model calculations (COMAGMAT-3.57) show that parental melts of two intrusions were close to high-Mg picrobasaltic magmas. The concentration of MgO in melt is 16.21 (Intrusion 1) and 16.17 (Intrusion 2). Isotopic data of Ortsog-Uul magmatic rocks exhibit different values of εNd (positive and negative) for Intrusion 1 and 2, respectively.

  10. Petrology of the Devonian gas-bearing shale along Lake Erie helps explain gas shows

    Energy Technology Data Exchange (ETDEWEB)

    Broadhead, R.F.; Potter, P.E.

    1980-11-01

    Comprehensive petrologic study of 136 thin sections of the Ohio Shale along Lake Erie, when combined with detailed stratigraphic study, helps explain the occurrence of its gas shows, most of which occur in the silty, greenish-gray, organic poor Chagrin Shale and Three Lick Bed. Both have thicker siltstone laminae and more siltstone beds than other members of the Ohio Shale and both units also contain more clayshales. The source of the gas in the Chagrin Shale and Three Lick Bed of the Ohio Shale is believed to be the bituminous-rich shales of the middle and lower parts of the underlying Huron Member of the Ohio Shale. Eleven petrographic types were recognized and extended descriptions are provided of the major ones - claystones, clayshales, mudshales, and bituminous shales plus laminated and unlaminated siltstones and very minor marlstones and sandstones. In addition three major types of lamination were identified and studied. Thirty-two shale samples were analyzed for organic carbon, whole rock hydrogen and whole rock nitrogen with a Perkin-Elmer 240 Elemental Analyzer and provided the data base for source rock evaluation of the Ohio Shale.

  11. Geochemistry and petrology of selected coal samples from Sumatra, Kalimantan, Sulawesi, and Papua, Indonesia

    International Nuclear Information System (INIS)

    Belkin, Harvey E.; Tewalt, Susan J.; Hower, James C.; Stucker, J.D.; O'Keefe, J.M.K.

    2009-01-01

    Indonesia has become the world's largest exporter of thermal coal and is a major supplier to the Asian coal market, particularly as the People's Republic of China is now (2007) and perhaps may remain a net importer of coal. Indonesia has had a long history of coal production, mainly in Sumatra and Kalimantan, but only in the last two decades have government and commercial forces resulted in a remarkable coal boom. A recent assessment of Indonesian coal-bed methane (CBM) potential has motivated active CBM exploration. Most of the coal is Paleogene and Neogene, low to moderate rank and has low ash yield and sulfur (generally < 10 and < 1 wt.%, respectively). Active tectonic and igneous activity has resulted in significant rank increase in some coal basins. Eight coal samples are described that represent the major export and/or resource potential of Sumatra, Kalimantan, Sulawesi, and Papua. Detailed geochemistry, including proximate and ultimate analysis, sulfur forms, and major, minor, and trace element determinations are presented. Organic petrology and vitrinite reflectance data reflect various precursor flora assemblages and rank variations, including sample composites from active igneous and tectonic areas. A comparison of Hazardous Air Pollutants (HAPs) elements abundance with world and US averages show that the Indonesian coals have low combustion pollution potential. (author)

  12. The petrologic evolution and pre-eruptive conditions of the rhyolitic Kos Plateau Tuff (Aegean arc)

    Science.gov (United States)

    Bachmann, Olivier

    2010-09-01

    The Kos Plateau Tuff is a large (>60 km3) and young (160 k.y.) calc-alkaline, high-SiO2 rhyolitic ignimbrite from the active Kos-Nisyros volcanic center in the Aegean arc (Greece). Combined textural, petrological and geochemical information suggest that (1) the system evolved dominantly by crystal fractionation from (mostly unerupted) more mafic parents, (2) the magma chamber grew over ≥ 250 000 years at shallow depth (˜1.5-2.5 kb) and was stored as a H2O-rich crystalline mush close to its solidus (˜670-750°C), (3) the eruption occurred after a reheating event triggered by the intrusion of hydrous mafic magma at the base of the rhyolitic mush. Rare banded pumices indicate that the mafic magma only mingled with a trivial portion of resident crystal-rich rhyolite; most of the mush was remobilized following partial melting of quartz and feldspars induced by advection of heat and volatiles from the underplated, hotter mafic influx.

  13. Mineralogical, petrological and geochemical aspects of alkaline and alkaline-carbonatite associations from Brazil

    Science.gov (United States)

    Morbidelli, L.; Gomes, C. B.; Beccaluva, L.; Brotzu, P.; Conte, A. M.; Ruberti, E.; Traversa, G.

    1995-12-01

    A general description of Mesozoic and Tertiary (Fortaleza) Brazilian alkaline and alkaline-carbonatite districts is presented with reference to mineralogy, petrology, geochemistry and geochronology. It mainly refers to scientific results obtained during the last decade by an Italo-Brazilian research team. Alkaline occurrences are distributed across Brazilian territory from the southern (Piratini, Rio Grande do Sul State) to the northeastern (Fortaleza, Ceará State) regions and are mainly concentrated along the borders of the Paraná Basin generally coinciding with important tectonic lineaments. The most noteworthy characteristics of these alkaline and alkaline-carbonatite suites are: (i) prevalence of intrusive forms; (ii) abundance of cumulate assemblages (minor dunites, frequent clinopyroxenites and members of the ijolite series) and (iii) abundance of evolved rock-types. Many data demonstrate that crystal fractionation was the main process responsible for magma evolution of all Brazilian alkaline rocks. A hypothesis is proposed for the genesis of carbonatite liquids by immiscibility processes. The incidence of REE and trace elements for different major groups of lithotypes, belonging both to carbonatite-bearing and carbonatite-free districts, are documented. Sr and preliminary Nd isotopic data are indicative of a mantle origin for the least evolved magmas of all the studied occurrences. Mantle source material and melting models for the generation of the Brazilian alkaline magma types are also discussed.

  14. Geologic map of Harrat Hutaymah, with petrologic classification and distribution of ultramafic inclusions, Saudi Arabia

    Science.gov (United States)

    Thornber, Carl R.

    1990-01-01

    This map shows detailed geology of the Quaternary and Tertiary volcanic deposits that comprise Harrat Hutaymah and an updated and generalized compilation of the underlying Proterozoic and Paleozoic basement rocks. Quaternary alluvial cover and details of basement geology (that is, faults, dikes, and other features) are not shown. Volcanic unit descriptions and contact relations are based upon field investigation by the author and on compilation and revision of mapping Kellogg (1984; northern half of area) and Pallister (1984; southern half of area). A single K-Ar date of 1.80 ± 0.05 Ma for an alkali olivine basalt flow transected by the Al Hutaymah tuff ring (Pallister, 1984) provides the basis for an estimated late Tertiary to Quaternary age range for all harrat volcanic units other than unit Qtr (tuff reworked during Quaternary age time). Contact relations and unit descriptions for the basement rocks were compiled from Pallister (1984), Kellogg (1984 and 1985), DuBray (1984), Johnson and Williams (1984), Vaslet and others (1987), Cole and Hedge (1986), and Richter and others (1984). All rock unit names in this report are informal and capitalization follows Saudi Arabian stratigraphic nomenclature (Fitch, 1980). Geographic information was compiled from Pallister (1984), Kellogg (1984), and Fuller (in Johnson and Williams, 1984) and from field investigation by the author in 1986. The pie diagrams on the map show the distribution and petrology of ultramafic xenoliths of Harrat Hutaymah. The pie diagrams are explained by a detailed classification of ultramafic xenoliths that is introduced in this report.

  15. Experimental petrology for the thermobarometric determination of mineral paragenesis: the fluid inclusions; Petrologia experimental para la determinacion termobarometrica de paragenesis minerales: las inclusiones fluidas

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Partida, Eduardo; Torres Rodriguez, Vicente; Birkle, Peter [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1994-05-01

    There is a great number of phenomena in nature in which some fluid participates as the main component. Such is the case of oil deposits formation, of metallic minerals, geothermal systems, metamorphic and diagenetic deposits. The common denominator of all of them is that in some part of their stages important physico-chemical processes occurred in the related fluids, leaving evidence of such phenomena in the fluid inclusions. The Geothermal Department has petrologic vanguard tools for reservoir problems resolution, since it has laboratories for the study on fluid inclusions by means of the technique called cryoscopic-microthermometry that permits the definition of physico-chemical conditions of the brine that participated or participates in the hydrothermal systems formation. The method simultaneously permits to know the characteristics of the initial brine that participated in the interaction water-rock phenomenon, observe the boiling phenomena, and determine conditions of initial pressure in the reservoirs. [Espanol] Existe un gran numero de fenomenos en la naturaleza en los que participa algun fluido como componente principal. Tal es el caso de la formacion de yacimientos de petroleo, de minerales metalicos, de sistemas geotermicos, yacimientos metamorficos y diageneticos. El comun denominador de todos ellos es que en alguna de sus etapas ocurrieron procesos fisicoquimicos importantes en los fluidos relacionados, quedando evidencia de tales fenomenos en las inclusiones fluidas. El Departamento de Geotermia cuenta con herramientas petrologicas de vanguardia para la resolucion de problemas en yacimientos, ya que tiene laboratorios para el estudio de las inclusiones fluidas por medio de la tecnica denominada microtermometria-crioscopica que permite definir condiciones fisicoquimicas de la salmuera que participo o participa en la formacion de sistemas hidrotermales. El metodo permite simultaneamente conocer las caracteristicas de la salmuera inicial que participo en

  16. World review: Middle East

    International Nuclear Information System (INIS)

    Anon.

    2000-01-01

    The article gives information on contracts announced (and to whom) and recently completed in some parts of the Middle East in the petroleum, natural gas and petrochemicals industries. Areas specifically mentioned are Bahrain, Egypt, Iran, Libya, Oman, Qatar, Saudi Arabia, Syria and the United Arab Emirates. The prospects for the petrochemical industry in particular are good and continued growth is expected. Gas is likely to make an increasingly important contribution to the prosperity of the Middle East and is expected to carry a higher priority than expansion of crude oil production

  17. Partial delamination of continental mantle lithosphere, uplift-related crust mantle decoupling, volcanism and basin formation: a new model for the Pliocene Quaternary evolution of the southern East-Carpathians, Romania

    Science.gov (United States)

    Chalot-Prat, F.; Girbacea, R.

    2000-11-01

    A geodynamic model is proposed for the Mid-Miocene to Quaternary evolution of the southern East-Carpathians in order to explain the relationships between shallow and deep geological phenomena that occurred synchronously during late-collision tectonics. In this area, an active volcanic zone cross-cuts since 2 My the suture between the overriding Tisza-Dacia and subducting European continental plates. Mafic calc-alkaline and alkaline magmas (south Harghita and Persani volcanoes) erupted contemporaneously. These magmas were supplied by partial melting of the mantle lithosphere of the subducting, and not of the overriding, plate. In an effort to decipher this geodynamically a-typical setting of magma generation, the spatial and temporal distribution of shallow and deep phenomena was successively examined in order to establish the degree of their interdependence. Our model indicates that intra-mantle delamination of the subducting European plate is the principal cause of a succession of events. It caused upwelling of the hot asthenosphere below a thinned continental lithosphere of the Carpathians, inducing the uplift of the lithosphere and its internal decoupling at the Moho level by isostatic and mostly thermal effects. During this uplift, the crust deformed flexurally whilst the mantle deformed in a ductile way. This triggered decompressional partial melting of the uppermost mantle lithosphere. Flexural deformation of the crust induced its fracturing, allowing for the rapid ascent of magmas to the surface, as well as reactivation of an older detachment horizon at the base of the Carpathian nappe stack above which the Brasov, Ciuc and Gheorghieni hinterland basins formed by extension and gravity spreading. The rapid subsidence of the Focsani foreland basin is controlled by the load exerted on the lithosphere by the delaminated mantle slab that is still attached to it. In this model, crust-mantle decoupling, magma genesis and volcanism, local near-surface hinterland

  18. Middle East political stability

    OpenAIRE

    2008-01-01

    Henry Siegman asks whether the next US President can rescue a two-state solution to the Israel–Palestine conflict; Lakhdar Brahimi discusses Iran – war or peace in the Middle East?; Eric Rouleau assesses the Iranian nuclear threat; Walid Khadduri looks at concerns over the future of Iraq and regional implications.

  19. East Asian welfare regime

    DEFF Research Database (Denmark)

    Abrahamson, Peter

    2017-01-01

    The paper asks if East Asian welfare regimes are still productivist and Confucian? And, have they developed public care policies? The literature is split on the first question but (mostly) confirmative on the second. Care has to a large, but insufficient extent, been rolled out in the region...

  20. Fleet Readiness Center East

    Science.gov (United States)

    ability to take care of our Customers, our People, and our Business. WHAT'S NEW ON FACEBOOK? weather icon S o cial Media Navy Twitter US Navy Pinterest US Navy Instagram FRC East Facebook US Navy Google FRCE ADVERSE WEATHER INFO Severe Weather Number: 252-464-8333 Visit us on Facebook for up-to-date

  1. Middle East Respiratory Syndrome (MERS)

    Science.gov (United States)

    Middle East Respiratory Syndrome Coronavirus; MERS-CoV; Novel coronavirus; nCoV ... for Disease Control and Prevention website. Middle East Respiratory Syndrome (MERS): Frequently asked questions and answers. www. ...

  2. Experimental and petrological constraints on local-scale interaction of biotite-amphibole gneiss with H2O-CO2-(K, NaCl fluids at middle-crustal conditions: Example from the Limpopo Complex, South Africa

    Directory of Open Access Journals (Sweden)

    Oleg G. Safonov

    2012-11-01

    Full Text Available Reaction textures and fluid inclusions in the ∼2.0 Ga pyroxene-bearing dehydration zones within the Sand River biotite-hornblende orthogneisses (Central Zone of the Limpopo Complex suggest that the formation of these zones is a result of close interplay between dehydration process along ductile shear zones triggered by H2O-CO2-salt fluids at 750–800 °C and 5.5–6.2 kbar, partial melting, and later exsolution of residual brine and H2O-CO2 fluids during melt crystallization at 650–700 °C. These processes caused local variations of water and alkali activity in the fluids, resulting in various mineral assemblages within the dehydration zone. The petrological observations are substantiated by experiments on the interaction of the Sand River gneiss with the H2O-CO2-(K, NaCl fluids at 750 and 800 °C and 5.5 kbar. It follows that the interaction of biotite-amphibole gneiss with H2O-CO2-(K, NaCl fluids is accompanied by partial melting at 750–800 °C. Orthopyroxene-bearing assemblages are characteristic for temperature 800 °C and are stable in equilibrium with fluids with low salt concentrations, while salt-rich fluids produce clinopyroxene-bearing assemblages. These observations are in good agreement with the petrological data on the dehydration zones within the Sand River orthogneisses.

  3. Depositional setting, petrology and chemistry of Permian coals from the Parana Basin: 2. South Santa Catarina Coalfield, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Kalkreuth, W.; Mexias, A.; Balbinot, M.; Levandowski, J. [Instituto de Geociencias, UFRGS, Porto Alegre (Brazil); Holz, M. [Inst. de Geociencias, UFBA, Salvador, Bahia (Brazil); Willett, J.; Finkelman, R. [U.S. Geological Survey, Reston, VA (United States); Burger, H. [Freie Universitaet Berlin, Geoinformatik, (Germany)

    2010-12-01

    In Brazil economically important coal deposits occur in the southern part of the Parana Basin, where coal seams occur in the Permian Rio Bonito Formation, with major coal development in the states of Rio Grande de Sul and Santa Catarina. The current paper presents results on sequence stratigraphic interpretation of the coal-bearing strata, and petrological and geochemical coal seam characterization from the South Santa Catarina Coalfield, Parana Basin. In terms of sequence stratigraphic interpretation the precursor mires of the Santa Catarina coal seams formed in an estuarine-barrier shoreface depositional environment, with major peat accumulation in a high stand systems tract (Pre-Bonito and Bonito seams), a lowstand systems tract (Ponta Alta seam, seam A, seam B) and a transgressive systems tract (Irapua, Barro Branco and Treviso seams). Seam thicknesses range from 1.70 to 2.39 m, but high proportions of impure coal (coaly shale and shaley coal), carbonaceous shale and partings reduce the net coal thickness significantly. Coal lithoypes are variable, with banded coal predominant in the Barro Branco seam, and banded dull and dull coal predominantly in Bonito and Irapua seams, respectively. Results from petrographic analyses indicate a vitrinite reflectance range from 0.76 to 1.63 %Rrandom (HVB A to LVB coal). Maceral group distribution varies significantly, with the Barro Branco seam having the highest vitrinite content (mean 67.5 vol%), whereas the Irapua seam has the highest inertinite content (33.8 vol%). Liptinite mean values range from 7.8 vol% (Barro Branco seam) to 22.5 vol% (Irapua seam). Results from proximate analyses indicate for the three seams high ash yields (50.2 - 64.2 wt.%). Considering the International Classification of in-Seam Coals, all samples are in fact classified as carbonaceous rocks (> 50 wt.% ash). Sulfur contents range from 3.4 to 7.7 wt.%, of which the major part occurs as pyritic sulfur. Results of X-ray diffraction indicate the

  4. Petrology and Rock Magnetism of the peridotites of Pindos Ophiolite (Greece), insights into the serpentinization process

    Science.gov (United States)

    Bonnemains, D.; Carlut, J. H.; Mevel, C.; Andreani, M.; Escartin, J.; Debret, B.

    2015-12-01

    We present a petrological and magnetic study of a suite of serpentinized peridotites from the Pindos ophiolite spanning a wide range in the degree of serpentinization (from ~10 to 100%). The Pindos ophiolite, in Northern Greece, is a portion of Late Triassic oceanic lithosphere obducted during the convergence of the Apulian and Pelagonian micro-continents. This ophiolite is interpreted mainly as the result of a supra-subduction zone spreading process but its complete history remains largely unknown. Therefore, it is not clear when the ultramafic section was exposed to fluid circulation that resulted in its serpentinization. Element partitioning during serpentinization reactions is dependent on parameters such as temperature and water-rock ratio. In particular, they affect the behavior of the iron released by olivine, which can be taken up either by magnetite, serpentine and/or brucite. Analyses of the reaction products are therefore a key to constrain the conditions during the main stage of the alteration. Our study was designed to gain insight on the conditions prevailing during hydration. Our results indicate that even fully serpentinized samples have a very low magnetization and magnetite content. Moreover, microprobe and μXanes results show that serpentine is the main host of iron in the divalent but also trivalent form. These results are compared with a set of data from serpentinized ultramafics sampled from the ocean floors, as well as from various other ophiolites. We suggest that serpentinization at Pindos occurred at relatively low-temperature (less than 200 °C), therefore not at a ridge environment. In addition, we stress that the presence of trivalent iron in serpentine indicates that serpentinization may remain a producer of hydrogen even when very little magnetite is formed.

  5. New insights on the petrology of submarine volcanics from the Western Pontine Archipelago (Tyrrhenian Sea, Italy)

    Science.gov (United States)

    Conte, A. M.; Perinelli, C.; Bianchini, G.; Natali, C.; Martorelli, E.; Chiocci, F. L.

    2016-11-01

    The Pontine Islands form a volcanic archipelago in the Tyrrhenian Sea. It consists of two edifices, the islands of Ponza, Palmarola and Zannone and the islands of Ventotene and Santo Stefano, respectively. The Archipelago developed during two main volcanic cycles in the Plio-Pleistocene: 1) the Pliocene episode erupted subalkaline, silica-rich volcanic units, which constitute the dominant products in the western edifice (Ponza and Zannone Islands); 2) the Pleistocene episode erupted more alkaline products, represented by evolved rocks (trachytes to peralkaline rhyolites) in the islands of Ponza and Palmarola and by basic to intermediate rocks in the eastern edifice (Ventotene and Santo Stefano Islands). In this paper we present new geochemical and petrological data from submarine rock samples collected in two oceanographic cruises and a scuba diving survey. The main result is the recovery of relatively undifferentiated lithotypes that provide further insights on the magmatic spectrum existing in the Pontine Archipelago, allowing modelling of the whole suite of rocks by fractional crystallization processes. New major and trace element data and thermodynamic constrains (by the software PELE) indicate the existence of three distinct evolutionary trends corresponding to a HK calcalkaline series in the Pliocene, followed by a transitional and then by a shoshonite series in the Pleistocene. In particular, the transitional series, so far overlooked in the literature, is required in order to explain the genesis of several peralkaline felsic rocks recognized in the Archipelago. On the whole, the new geochemical data i) confirm the orogenic signature of the suites, ii) allow to rule out an anatectic origin for both subalkaline and peralkaline rhyolites and iii) indicate highly heterogeneous mantle sources, due to crustal components variously recycled in the mantle via subduction.

  6. Petrological Geodynamics of Mantle Melting II. AlphaMELTS + Multiphase Flow: Dynamic Fractional Melting

    Science.gov (United States)

    Tirone, Massimiliano

    2018-03-01

    In this second installment of a series that aims to investigate the dynamic interaction between the composition and abundance of the solid mantle and its melt products, the classic interpretation of fractional melting is extended to account for the dynamic nature of the process. A multiphase numerical flow model is coupled with the program AlphaMELTS, which provides at the moment possibly the most accurate petrological description of melting based on thermodynamic principles. The conceptual idea of this study is based on a description of the melting process taking place along a 1-D vertical ideal column where chemical equilibrium is assumed to apply in two local sub-systems separately on some spatial and temporal scale. The solid mantle belongs to a local sub-system (ss1) that does not interact chemically with the melt reservoir which forms a second sub-system (ss2). The local melt products are transferred in the melt sub-system ss2 where the melt phase eventually can also crystallize into a different solid assemblage and will evolve dynamically. The main difference with the usual interpretation of fractional melting is that melt is not arbitrarily and instantaneously extracted from the mantle, but instead remains a dynamic component of the model, hence the process is named dynamic fractional melting (DFM). Some of the conditions that may affect the DFM model are investigated in this study, in particular the effect of temperature, mantle velocity at the boundary of the mantle column. A comparison is made with the dynamic equilibrium melting (DEM) model discussed in the first installment. The implications of assuming passive flow or active flow are also considered to some extent. Complete data files of most of the DFM simulations, four animations and two new DEM simulations (passive/active flow) are available following the instructions in the supplementary material.

  7. Decarbonation in an intracratonic setting: Insight from petrological-thermomechanical modeling

    Science.gov (United States)

    Gonzalez, Christopher M.; Gorczyk, Weronika

    2017-08-01

    Cratons form the stable core roots of the continental crust. Despite long-term stability, cratons have failed in the past. Cratonic destruction (e.g., North Atlantic Craton) due to chemical rejuvenation at the base of the lithosphere remains poorly constrained numerically. We use 2-D petrological-thermomechanical models to assess cratonic rifting characteristics and mantle CO2 degassing in the presence of a carbonated subcontinental lithospheric mantle (SCLM). We test two tectonothermal SCLM compositions: Archon (depleted) and Tecton (fertilized) using 2 CO2 wt % in the bulk composition to represent a metasomatized SCLM. We parameterize cratonic breakup via extensional duration (7-12 Ma; full breakup), tectonothermal age, TMoho (300-600°C), and crustal rheology. The two compositions with metasomatized SCLMs share similar rifting features and decarbonation trends during initial extension. However, we show long-term (>67 Ma) stability differences due to lithospheric density contrasts between SCLM compositions. The Tecton model shows convective removal and thinning of the metasomatized SCLM during failed rifting. The Archon composition remained stable, highlighting the primary role for SCLM density even when metasomatized at its base. In the short-term, three failed rifting characteristics emerge: failed rifting without decarbonation, failed rifting with decarbonation, and semifailed rifting with dry asthenospheric melting and decarbonation. Decarbonation trends were greatest in the failed rifts, reaching peak fluxes of 94 × 104 kg m-3. Increased TMoho did not alter the effects of rifting or decarbonation. Lastly, we show mantle regions where decarbonation, mantle melting in the presence of carbonate, and preservation of carbonated mantle occur during rifting.

  8. Coupled petrological-geodynamical modeling of a compositionally heterogeneous mantle plume

    Science.gov (United States)

    Rummel, Lisa; Kaus, Boris J. P.; White, Richard W.; Mertz, Dieter F.; Yang, Jianfeng; Baumann, Tobias S.

    2018-01-01

    Self-consistent geodynamic modeling that includes melting is challenging as the chemistry of the source rocks continuously changes as a result of melt extraction. Here, we describe a new method to study the interaction between physical and chemical processes in an uprising heterogeneous mantle plume by combining a geodynamic code with a thermodynamic modeling approach for magma generation and evolution. We pre-computed hundreds of phase diagrams, each of them for a different chemical system. After melt is extracted, the phase diagram with the closest bulk rock chemistry to the depleted source rock is updated locally. The petrological evolution of rocks is tracked via evolving chemical compositions of source rocks and extracted melts using twelve oxide compositional parameters. As a result, a wide variety of newly generated magmatic rocks can in principle be produced from mantle rocks with different degrees of depletion. The results show that a variable geothermal gradient, the amount of extracted melt and plume excess temperature affect the magma production and chemistry by influencing decompression melting and the depletion of rocks. Decompression melting is facilitated by a shallower lithosphere-asthenosphere boundary and an increase in the amount of extracted magma is induced by a lower critical melt fraction for melt extraction and/or higher plume temperatures. Increasing critical melt fractions activates the extraction of melts triggered by decompression at a later stage and slows down the depletion process from the metasomatized mantle. Melt compositional trends are used to determine melting related processes by focusing on K2O/Na2O ratio as indicator for the rock type that has been molten. Thus, a step-like-profile in K2O/Na2O might be explained by a transition between melting metasomatized and pyrolitic mantle components reproducible through numerical modeling of a heterogeneous asthenospheric mantle source. A potential application of the developed method

  9. Petrological mineralogical and geochemical characterization of the granitoids and fracture fillings developed in Ratones Mines (Spain)

    International Nuclear Information System (INIS)

    Buil Gutierrez, B.

    2002-01-01

    The petrological, mineralogical and geochemical characterisation of the granitoids and fracture fillings developed in the Ratones Mine (Caceres, Spain) has been done in order to understand rock-water interaction processes which control water geochemical parameters. Special interest has been devoted to the analysis and interpretation of REE patterns in the solid phase (granitoids and fracture fillings) because they constitute geochemical tracers in water-rock interaction process. Moreover, REE are considered as actinide analogues. In order to characterise the solid phase (granitoids and fracture fillings) several investigation scales (system, outcrop, whole rock, mineral and geochemical components) have been considered and different types of samples have been analysed. These factors control the methodological approach used in this investigation. The analytical methods we have used in this investigation are microscope, qualitative and semi-quantitative methods (XRD, SEM,EDAX) and quantitative methods (ICP-MS, XRF, EM, LAM-IC-MS). The bulk of the granitoids located around the Ratones Mine Belongs to the alkaline feldspar granite-sienogranite lihotype and they show a peraluminous and subalkaline pattern. From the mineralogical point of view, they are composed by quartz, K-feldspar (Or>90%), showing sericitation, moscovitization and turmolinization altherations, alkaline plagioclase (An-=-3%), usually altered to sericite, saussirite and less frequently affected by moscovitization processes, Fe-Al biotite, frequently affected by chloritization processes and sometimes replaced by muscovite, and finally muscovite (>2% celadonite and <4% paragonite) both of primary and secondary origin. The differences observed between the different lithotypes are related with the modal proportion of the principal minerals,with the presence or absence of certain accessory minerals ( turmaline, cordierite), with specific textural patterns, grain size and also with the richness in specific

  10. Petrological constraints on melt generation beneath the Asal Rift (Djibouti) using quaternary basalts

    Science.gov (United States)

    Pinzuti, Paul; Humler, Eric; Manighetti, Isabelle; Gaudemer, Yves

    2013-08-01

    The temporal evolution of the mantle melting processes in the Asal Rift is evaluated from the chemical composition of 56 new lava flows sampled along 10 km of the rift axis and 9 km off-axis (i.e., erupted within the last 620 kyr). Petrological and primary geochemical results show that most of the samples of the inner floor of the Asal Rift are affected by plagioclase accumulation. Trace element ratios and major element compositions corrected for mineral accumulation and crystallization show a symmetric pattern relative to the rift axis and preserved a clear signal of mantle melting depth variations. While FeO, Fe8.0, Zr/Y, and (Dy/Yb)N decrease from the rift shoulders to the rift axis, SiO2, Na/Ti, Lu/Hf increase and Na2O and Na8.0 are constant across the rift. These variations are qualitatively consistent with shallow melting beneath the rift axis and deeper melting for off-axis lava flows. Na8.0 and Fe8.0 contents show that beneath the rift axis, melting paths are shallow, from 81 ± 4 to 43 ± 5 km. These melting paths are consistent with adiabatic melting in normal-temperature fertile asthenosphere, beneath an extensively thinned mantle lithosphere. On the contrary, melting on the rift shoulders (from 107 ± 7 to 67 ± 8 km) occurred beneath thicker lithosphere, requiring a mantle solidus temperature 100 ± 40°C hotter. In this geodynamic environment, the calculated rate of lithospheric thinning appears to be 4.0 ± 2.0 cm yr-1, a value close to the mean spreading rate (2.9 ± 0.2 cm yr-1) over the last 620 kyr.

  11. Petrology And Geochemistry Of Barite Mineralisation Around Azara North Central Nigeria

    Directory of Open Access Journals (Sweden)

    Tanko

    2015-05-01

    Full Text Available ABSTRACT The Azara barite deposits formed parts of Middle Benue Trough which is located in an elongated rift or faulted-bounded mega structural depression trending NE-SW to a length of over 1000 km and a width of 100 km.Petrological and geochemical investigations of Azrara barite deposits were carried out. Eight 8 selected samples of barites were collected from the veins four from known veins V1V3V17 and V 18 and four from new veins VAVBVCand VD werecarried out with the aim of determining their mineralisation potentials using petrographic studies and gravimetric method of analyses. The Petrographic studies of some of the thin section of the samples conducted using a polarizing microscope to determine the contents distributions and textures of the various veins Table 1. The weight percentage composition of barite in the samples are V1 86.39 VC82.61 V1881.48 V3 81.17 V17 79.82 VA78.94 VB76.82 and VD 70.55 respectively. It is deduced from this work that the chemical weathering of the carbonates resulted in two distinct types of barites Barite associated with mainly quartz SiO2 and limonite FeOOH.nH2O as major gangue and barite with siderite Ferrous Carbonate with high amount of Mg ankerite Ca Fe Mg CO3 and Calcite CaCO3. The outcomes were compared with the barite specification of Weigal1937 of 95.00 and were found to be good for making drilling mud for use in the oil industry paints and other chemicals

  12. Facilitating Research and Learning in Petrology and Geochemistry through Classroom Applications of Remotely Operable Research Instrumentation

    Science.gov (United States)

    Ryan, J. G.

    2012-12-01

    Bringing the use of cutting-edge research tools into student classroom experiences has long been a popular educational strategy in the geosciences and other STEM disciplines. The NSF CCLI and TUES programs have funded a large number of projects that placed research-grade instrumentation at educational institutions for instructional use and use in supporting undergraduate research activities. While student and faculty response to these activities has largely been positive, a range of challenges exist related to their educational effectiveness. Many of the obstacles these approaches have faced relate to "scaling up" of research mentoring experiences (e.g., providing training and time for use for an entire classroom of students, as opposed to one or two), and to time tradeoffs associated with providing technical training for effective instrument use versus course content coverage. The biggest challenge has often been simple logistics: a single instrument, housed in a different space, is difficult to integrate effectively into instructional activities. My CCLI-funded project sought primarily to knock down the logistical obstacles to research instrument use by taking advantage of remote instrument operation technologies, which allow the in-classroom use of networked analytical tools. Remote use of electron microprobe and SEM instruments of the Florida Center for Analytical Electron Microscopy (FCAEM) in Miami, FL was integrated into two geoscience courses at USF in Tampa, FL. Remote operation permitted the development of whole-class laboratory exercises to familiarize students with the tools, their function, and their capabilities; and it allowed students to collect high-quality chemical and image data on their own prepared samples in the classroom during laboratory periods. These activities improve student engagement in the course, appear to improve learning of key concepts in mineralogy and petrology, and have led to students pursuing independent research projects, as

  13. Petrologic, morphologic and functional analyses of ground and abrasive stone tools from Rug Bair, Ovche Pole valley

    International Nuclear Information System (INIS)

    Boev, Blazho; Dimitrovska, Vasilka

    2011-01-01

    This paper represents the results of the ground and abrasive stone tools analyses based on the finds collected during the excavation of Rug Bair undertaken in 1970, and today stored in the Museum and Institute for Protection of Shtip. The studies were made possible with the help from the Faculty of Natural and Technical Sciences, Shtip, Republic of Macedonia. Through the stone material, an attempt was made a more comprehensive picture of the raw material, petrologic, technical and typo logical characteristics of the Neolithic stone industry at this site to be gained as well as its relationship with related simultaneously industries. (Author)

  14. Brine/Rock Interaction in Deep Oceanic Layered Gabbros: Petrological Evidence from Cl-Rich Amphibole, High-Temperature Hydrothermal Veins, and Experiments

    Science.gov (United States)

    Currin Sala, A. M.; Koepke, J.; Almeev, R. R.; Teagle, D. A. H.; Zihlmann, B.; Wolff, P. E.

    2017-12-01

    Evidence of high temperature brine/rock interaction is found in hydrothermal veins and dykelets that cross-cut layered olivine gabbros in the deep palaeocrust of the Sumail Ophiolite, Sultanate of Oman. Here we present petrological and geochemical data from these samples, and an experimental attempt to simulate brine/gabbro interaction using externally heated cold seal pressure vessels. The studied natural veins and dykelets contain pargasite, hornblende, actinolite, and Cl-rich pargasite with up to 5 wt% Cl, showing a range of formation conditions from magmatic to metamorphic (hydrothermal) and thus a complex history of brine/rock interaction. In addition, the isotopic study of the radiogenic 87/86Sr and stable 18O in different amphibole types provide an estimate for the extent of seawater influence as alteration agent in the veins of the studied samples. Experiments performed at 750 °C and 200 MPa with different starting materials (chlorine-free amphibole, olivine gabbro powder) and 20 wt% NaCl aqueous brine, illustrate the process by which gabbro-hosted amphibole-rich veins evolve at subsolidus temperatures in the presence of a seawater-derived fluid. Our results demonstrate a decrease in olivine, plagioclase and magnetite content in favour of hastingsite, pargasite and magnesiohornblende, a decrease of IVAl and Ti in the starting amphibole, and an increase in Cl in amphibole, up to 0.2 Cl wt%. Our experiments show the change of magmatic pargasite towards more magnesium and silica-rich end members with results comparable to mildly chlorine-rich pargasites and hornblendes found in the natural samples studied. However, the experimental setup also presents limitations in the attainment of very high-chlorine amphibole (up to 5 wt%). Our analytical and experimental results provide further evidence for the existence of a hydrothermal cooling system in the deep oceanic crust.

  15. Petrology, palynology and organic geochemistry of Eocene lignite of Matanomadh, Kutch Basin, western India: Implications to depositional environment and hydrocarbon source potential

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Suryendu; Mathews, Runcie P.; Saraswati, Pratul K.; Banerjee, Santanu [Department of Earth Sciences, Indian Institute of Technology Bombay (India); Singh, Bhagwan D.; Tripathi, Suryakant M.; Singh, Alpana [Birbal Sahni Institute of Palaeobotany, Lucknow (India); Mann, Ulrich [Forschungszentrum Juelich (Germany). Institut fuer chemie und Dynamik der Geosphaere

    2011-01-01

    Petrological, palynological and organic-geochemical investigations were undertaken to determine the source vegetation, depositional conditions and hydrocarbon source potential of Eocene Matanomadh lignites from Kutch Basin, western India. The maceral study reveals that studied lignites are rich in huminite (av. 63%) with sub-ordinate amount of liptinite (av. 19%) and low inertinite (av. 3%), along with low to moderately high associated mineral matters (av. 15%). The overall petrographic composition points to a lagoonal condition for the formation of these lignites. The mean huminite reflectance values (R{sub r}: 0.28-0.34%, av. 0.31%) as well as low Rock-Eval T{sub max} (av. 417 C) values for the seams, suggest brown coal or lignitic stage/rank for the studied lignites. The palynological assemblages, dominated by tropical angiospermic pollen, suggest prevalence of warm humid tropical climate during the deposition of these lignites. The total organic carbon (TOC) content of lignites ranges between 26 and 58 wt.%, whereas the TOC content of the associated carbonaceous shales is around 4 wt.%. The Hydrogen Index (HI) ranging from 23 to 452 mg HC/g TOC indicates that the lignite sequence has the potential to produce mixed oil and gaseous hydrocarbons on maturation. The major pyrolysis products of lignites, derived from Curie point pyrolysis-GC-MS, are straight chain aliphatics, phenols and cadalene-based C{sub 15} bicyclic sesquiterpenoids. The exclusive occurrence of C{sub 15} bicyclic sesquiterpenoids suggests that these compounds are derived from dammar resin of angiosperm plants, belonging to family Dipterocarpaceae. (author)

  16. JPRS Report, East Europe

    Science.gov (United States)

    1990-05-04

    ments, they actively advertise their readiness to enter 90GE0031A East Berlin A USSENWIRTSCHAFT a barter deal and they will accept it as long as...AG it comprises the following aspects: has set up two joint ventures in the USSR producing shoes; Adidas has one joint venture in Hungary.) Joint...administration until product development, advertising , and marketing. In the repayment of long-term credits. Consortiums addition, the Soviet firm is interested

  17. Geochemistry and Mineral Chemistry of Zeolites Bearing Basic Volcanic Rocks from the Boumehen-Roudehen Area, East of Tehran

    Directory of Open Access Journals (Sweden)

    Amir Ali Tabbakh Shabani

    2017-11-01

    Full Text Available Introduction The Upper Eocene basic volcanic rocks that have cropped out in Karaj formation in the Boumehen and Roudehen area in the east of Tehran are characterized by fibrous zeolites filling their vesicles, cavities and fractures creating amygdale texture. The study area is located structurally in the Central Alborz orogenic belt. The presence of large volumes of shoshonitic magma during the Middle to Late Eocene in southern–central Alborz implies that partial melting to produce shoshsonitic melts was not a local petrological event. Thus, their ages, formation processes, and interpretations are of regional tectonic significance. In this study, we present a detailed petrography, mineral chemistry, and whole-rock geochemistry of high-K (shoshonitic basic rocks to understand the petrogenesis and source region and to deduce the nature of the tectonomagmatic regime of the Alborz. Materials and methods In this study, we present new major and trace element data for a selection of 4 of the least altered samples by a combination of X-ray fluorescence (XRF and ICP-OES techniques at the Zarazma Mineral Studies Company. Mineral analyses were obtained by wavelength dispersive X-ray spectrometry on polished thin sections prepared from each rock sample described above for 12 elements using a Cameca SX-50 electron microprobe at the Istituto di Geologia e Geoingegneria Ambientale, C.N.R., University La Sapienza of Rome, Italy. Typical beam operating conditions were 15 kV and probe current of 15 nA. The accuracy of the analyses is 1% for major and 10% for minor elements. A total of 24 point analyses were collected. Results and Discussion The extent of alteration in the study rocks varies from slight to severe and shows porphyritic to glomeroporphyritic textures. Pyroxenes are generally subhedral to euhedral and occur as discrete crystals as well as aggregates. Olivine may occur only as relics filled with iddingsite, chlorite and calcite. Plagioclase is

  18. Formation of fast-spreading lower oceanic crust as revealed by a new Mg-REE coupled geospeedometer

    Science.gov (United States)

    Sun, Chenguang; Lissenberg, C. Johan

    2018-04-01

    A new geospeedometer is developed based on the differential closures of Mg and rare earth element (REE) bulk-diffusion between coexisting plagioclase and clinopyroxene. By coupling the two elements with distinct bulk closure temperatures, this speedometer can numerically solve the initial temperatures and cooling rates for individual rock samples. As the existing Mg-exchange thermometer was calibrated for a narrow temperature range and strongly relies on model-dependent silica activities, a new thermometer is developed using literature experimental data. When the bulk closure temperatures of Mg and REE are determined, respectively, using this new Mg-exchange thermometer and the existing REE-exchange thermometer, this speedometer can be implemented for a wide range of compositions, mineral modes, and grain sizes. Applications of this new geospeedometer to oceanic gabbros from the fast-spreading East Pacific Rise at Hess Deep reveal that the lower oceanic crust crystallized at temperatures of 998-1353 °C with cooling rates of 0.003-10.2 °C/yr. Stratigraphic variations of the cooling rates and crystallization temperatures support deep hydrothermal circulations and in situ solidification of various replenished magma bodies. Together with existing petrological, geochemical and geophysical evidence, results from this new speedometry suggest that the lower crust formation at fast-spreading mid-ocean ridges involves emplacement of primary mantle melts in the deep section of the crystal mush zone coupled with efficient heat removal by crustal-scale hydrothermal circulations. The replenished melts become chemically and thermally evolved, accumulate as small magma bodies at various depths, feed the shallow axial magma chamber, and may also escape from the mush zone to generate off-axial magma lenses.

  19. A petrological study of Paleoarchean rocks of the Onverwacht Group: New insights into the geologic evolution of the Barberton Greenstone Belt, South Africa

    Science.gov (United States)

    Grosch, E. G.; Mcloughlin, N.; Abu-Alam, T. S.; Vidal, O.

    2012-12-01

    This study presents a multi-disciplinary petrological approach applied to surface samples and a total of 800 m of scientific drill core that furthers our understanding of the geologic evolution of the ca. 3.5 to 3.2 Ga Onverwacht Group of the Barberton greenstone belt (BGB), South Africa. Detrital zircon grains in coarse (diamictite) to fine-grained clastic sedimentary rocks of the Noisy formation (drill core KD2a) that unconformably overlies the volcanic ca. 3472 Ma Hooggenoeg Formation, are investigated by laser ablation LA-ICP-MS to constrain their 207Pb/206Pb ages for depositional age and provenance. A wide range in 207Pb/206Pb ages between ca. 3600 and 3430 Ma is reported, corresponding to surrounding TTG plutons and the ca.3667-3223 Ma Ancient Gneiss Complex. The youngest detrital zircon grain identified has an age of 3432 ± 10 Ma. Given the short time interval for a major change in geologic environment between ca. 3472 Ma and ca. 3432 Ma, it is argued here, that the Noisy formation is the earliest tectonic basin in the BGB, which developed during major tectonic uplift at ca. 3432 Ma. In the overlying ca. 3334 Ma Kromberg type-section, application of a chlorite thermodynamic multi-equilibrium calculation, dioctahedral mica hydration-temperature curve and pseudosection modelling, indicates a wide range in metamorphic conditions from sub-greenschist to the uppermost greenschist facies across the Kromberg type-section. A central mylonitic fuchsite-bearing zone, referred to as the Kromberg Section Mylonites, records at least two metamorphic events: a high-T, low-P (420 ± 30oC, sedimentary sequence contains detrital and diagenetic pyrites with a significant variation in Δ33S of -0.62 to +1.4‰ and δ34SCDT between -7.00 and +12.6‰ in the upper turbidite unit, to more narrow isotopic ranges with magmatic-atmospheric values in the underlying polymictitic diamictite. A sedimentary quartz-pyrite vein in the diamictite records the largest range and most negative

  20. Investigation on type and origin of iron mineralization at Mesgar occurrence, south of Zanjan, using petrological, mineralogical and geochemical data

    Directory of Open Access Journals (Sweden)

    Mohammad Ebrahimi

    2015-04-01

    rock-fluid interaction in Mesgar. Comparison of the geological, mineralogical, geochemical, textural and structural characteristics of the Mesgar occurrence with different types of iron deposits reveals that iron mineralization at Mesgar is originally formed as volcano-sedimentary, and then reconcentrated as vein mineralization by hydrothermal fluids (Barker, 1995; Marschik and Fontbote, 2001, Shahidi et al., 2012. Acknowledgements The authors are grateful to the University of Zanjan Grant Commission for research funding. Journal of Economic Geology reviewers and editor are also thanked for their constructive suggestions on alterations to the manuscript. References Barker, D.S., 1995. Crystallization and alteration of quartz monzonite, Iron Spring mining district, Utah, relation to associated iron deposits. Economic Geology, 90 (8: 2197–2217. Chappell, B.W. and White, A.J.R., 1974. Two contrasting granite types. Pacific Geology, 8(2: 173–174. Harris, N.B.W., Pearce, J.A. and Tindle, A.G., 1986. Geochemical characteristics of collision-zone magmatism. In: M.P. Coward, and A.C. Ries (Editors, Collision Tectonics. Geological Society of London, Special Publication, pp. 67–81. Kuster, D. and Harms, U., 1998. Post-collisional potassic granitoids from the southern and northern parts of the Late Neoproterozoic East Africa Orogen: a review. Lithos, 45(1: 177–195. Marschik, R. and Fontbote, L., 2001. The Candelaria-Punta Del Cobre iron oxide Cu-Au (-Zn-Ag deposits, Chile. Economic Geology, 96(8: 1799–1826. Miyashiro, A., 1977. Nature of alkalic volcanic series. Contributions to Mineralogy and Petrology, 66(1: 91–110. Rādfar, J., Mohammadiha, K. and Ghahraeipour, M., 2005. Geological map of Zarrin Rood (Garmab, scale 1:100,000. Geological Survey of Iran. Shahidi, E., Ebrahimi, M. and Kouhestani, H., 2012. Structure, texture and mineralography of Mesgar iron occurrence, south Gheydar. 4th Symposium of Iranian Society of Economic Geology, University of Birjand, Birjand

  1. Geochemical and petrological considerations about the basalts of upper aluminium in the Fildes Peninsula. (Rei George), Antartica

    International Nuclear Information System (INIS)

    Machado, A.; Fernandes de Lima, E.; Chemale, F.

    1998-01-01

    Petrographic, geochemical and petrological studies of lower Tertiary basaltic rocks from Fildes Peninsula in Antarctica were made to characterize their source and magmatic evolution. These basaltic rocks have porphyritic, glomeroporphyritic, intergranular and intersertal textures. The phenocrysts are of plagioclase (An), augite, pigeonite and Ti-magnetite. These basaltic rocks have AL O from 16 to 22%, Ni from 6 to 88 ppm, Co from 24 to 33 ppm and Cr from 54 to 123 ppm. Enrichment of Rb. Ba, Sr and LREE with respect to HREE is observed as relative depleted in HFSE is detected. The mass balance realized to understand the evolution of liquid that gave source the different basaltic rocks. Showed that the extracted mineral fractions were 76% of plagioclase, 2% of clinopiroxene and 21% of olivine. The intermediate volcanic rocks of Fildes Peninsula can be explained by cristalization fractionation of a basic liquid. The isotopic dates showed initial rations of Sr/Sr <0,704 and positive values of Nd epsilon. These results are strong support a mantelic source for basaltic rocks of Fildes Peninsula. On basis of geochemical, petrological and isotopic characteristics is possible concluded that these rocks were formed in an island are environment with parcial melting of mantle wedge. (author)

  2. Progress in 1988 1990 with computer applications in the ``hard-rock'' arena: Geochemistry, mineralogy, petrology, and volcanology

    Science.gov (United States)

    Rock, Nicholas M. S.

    This review covers rock, mineral and isotope geochemistry, mineralogy, igneous and metamorphic petrology, and volcanology. Crystallography, exploration geochemistry, and mineral exploration are excluded. Fairly extended comments on software availability, and on computerization of the publication process and of specimen collection indexes, may interest a wider audience. A proliferation of both published and commercial software in the past 3 years indicates increasing interest in what traditionally has been a rather reluctant sphere of geoscience computer activity. However, much of this software duplicates the same old functions (Harker and triangular plots, mineral recalculations, etc.). It usually is more efficient nowadays to use someone else's program, or to employ the command language in one of many general-purpose spreadsheet or statistical packages available, than to program a specialist operation from scratch in, say, FORTRAN. Greatest activity has been in mineralogy, where several journals specifically encourage publication of computer-related activities, and IMA and MSA Working Groups on microcomputers have been convened. In petrology and geochemistry, large national databases of rock and mineral analyses continue to multiply, whereas the international database IGBA grows slowly; some form of integration is necessary to make these disparate systems of lasting value to the global "hard-rock" community. Total merging or separate addressing via an intelligent "front-end" are both possibilities. In volcanology, the BBC's videodisk Volcanoes and the Smithsonian Institution's Global Volcanism Project use the most up-to-date computer technology in an exciting and innovative way, to promote public education.

  3. Garnet Signatures in Geophysical and Geochemical Observations: Insights into the Thermo-Petrological Structure of Oceanic Upper Mantle

    Science.gov (United States)

    Grose, C. J.; Afonso, J. C.

    2013-12-01

    We have developed new physically comprehensive thermal plate models of the oceanic lithosphere which incorporate temperature- and pressure-dependent heat transport properties and thermal expansivity, melting beneath ridges, hydrothermal circulation near ridge axes, and insulating oceanic crust. These models provide good fits to global databases of seafloor topography and heat flow, and seismic evidence of thermal structure near ridge axes. We couple these thermal plate models with thermodynamic models to predict the petrology of oceanic lithosphere. Geoid height predictions from our models suggest that there is a strong anomaly in geoid slope (over age) above ~25 Ma lithosphere due to the topography of garnet-field mantle. A similar anomaly is also present in geoid data over fracture zones. In addition, we show that a new assessment of a large database of ocean island basalt Sm/Yb systematics indicates that there is an unmistakable step-like increase in Sm/Yb values around 15-20 Ma, indicating the presence of garnet. To explain this feature, we have attempted to couple our thermo-petrological models of oceanic upper mantle with an open system, non-modal, dynamic melting model with diffusion kinetics to investigate trace element partitioning in an ascending mantle column.

  4. Petrology, Geochemistry and Tectonomagmatic Setting of Farmahin Volcanic Rocks (North of Arak

    Directory of Open Access Journals (Sweden)

    Reza Zarei Sahamieh

    2018-04-01

    fractional crystallization (AFC were the dominant processes in the genesis of the studied volcanic rocks. As a conclusion and according to field evidence and geochemical characteristics presented in this article, the studied area is composed of lava flows and pyroclastic rocks such as andesite, dacite, rhyodacite, ignimbrite, tuff and tuffits that cross cut by younger dykes and belong to the middle to late Eocene age (middle to upper Lutetien. According to Sm/Yb vs. Sm diagram (Aldanmaz et al., 2000, all the studied samples in terms of composition are similar to enriched mantle-derived melts that are generated by varying degrees of partial melting (10% - 20% from a spinel lherzolite to spinel-garnet lherzolite source. Considering the evidences, all rocks in the studied area belong to the subduction zone and the parent magma originated from mantle and was contaminated with continental crust during eruption and rising. Acknowledgments The authors wish to thank the Journal Manager and reviewers who critically reviewed the manuscript and made valuable suggestions for its improvement. References Aldanmaz, E., Pearce, J.A., Thirlwall, M.F. and Mitchell, J.G., 2000. Petrogenetic evolution of late Cenozoic, post-collision volcanism in western Anatolia, Turkey. Journal of Volcanology and Geothermal Research, 102(1–2: 67–95. Ghasemi, A. and Talbot, C.J., 2006. A new scenario for the Sanandaj-Sirjan zone (Iran. Journal of Asian Earth Sciences, 26 (6: 683–693. Hajian, J., 1970. Geological map of Farmahin, scale1:100000. Geological Survey of Iran. Irvine, T.N. and Baragar, W.R.A., 1971. A guide to the chemical classification of the common volcanic rocks. Canadian Journal of Earth Sciences, 8(5: 523–548. Le Bas, M.J., Le Maitre, R.W., Streckeisen, A. and Zanettin, B., 1986. A chemical classification of volcanic rocks based on the total alkali silica diagram. Journal of Petrology, 27 (3:745–750. Morimoto, N., Fabrise, J., Ferguson, A., Ginzburg, I.V., Ross, M., Seifert, F

  5. Simulated East-west differences in F-region peak electron density at Far East mid-latitude region

    Science.gov (United States)

    Ren, Z.; Wan, W.

    2017-12-01

    In the present work, using Three-Dimensional Theoretical Ionospheric Model of the Earth in Institute of Geology and Geophysics, Chinese Academy of Sciences (TIME3D-IGGCAS), we simulated the east-west differences in Fregion peak electron density (NmF2) at Far East mid-latitude region.We found that, after removing the longitudinal variations of neutral parameters, TIME3D-IGGCAS can better represent the observed relative east-west difference (Rew) features. Rew is mainly negative (West NmF2 > East NmF2) at noon and positive (East NmF2 >West NmF2) at evening-night. The magnitude of daytime negative Rew is weak at local winter and strong at local summer, and the daytime Rew show two negative peaks around two equinoxes. With the increasing of solar flux level, the magnitude of Rew mainly become larger, and two daytime negative peaks slight shifts to June Solstice. With the decreasing of geographical latitude, Rew mainly become positive, and two daytime negative peaks slight shifts to June Solstice. Our simulation also suggested that the thermospheric zonal wind combined with the geomagnetic field configuration play a pivotal role in the formation of the ionospheric east-west differences at Far East midlatitude region.

  6. Petrology and Geochemistry of Serpentinized Peridotites from a Bonin Fore-arc Seamount

    Science.gov (United States)

    Tian, L.; Tuoyu, W.; Dong, Y. H.; Gao, J.; Wu, S.

    2016-12-01

    Serpentinites, which contain up to 13 wt.% of water, are an important reservoir for chemical recycling in subduction zones. During the last two decades, many observations documented the occurrence of fore-arc mantle serpentinites in different locations. Here, we present petrology and whole rock chemistry for serpentinized peridotites dredged from the Hahajima Seamount, which is located 20-60 km west of the junction of the Bonin Trench and the Mariana Trench. Combined with published geochemical data of serpentinites from the Torishima Seamount, Conical Seamount and South Chamorro Seamount in the Izu-Bonin-Mariana fore-arc region, it will allow us to better understand the average composition of serpentinized fore-arc mantle overlying the subducting slab and the role of serpentinized mantle playing in the subduction zone geochemical cycle. The studied ultramafic rocks from the Hahajima Seamount are extensively serpentinized and hydrated (73 to 83%), with loss of ignition values ranging between 13 and 15 wt.%. Our results show that the serpentinized peridotites have Mg number from 88 to 90, and the average MgO/SiO2 is 0.93. The average Al2O3 (0.48 wt.%) and CaO (0.23 wt.%) contents are very low, consistent with low clinopyroxene abundances, and the overall depleted character of the mantle harzburgite protoliths. The serpentinized peridotites from the Hahajima Seamount exhibit similar "U" shape rare earth element (REE) patterns ([La/Sm]N = 3.1-3.6), at higher overall abundances, to the Conical and South Chamorro Seamount suites. One exceptional sample shows the similar REE pattern as serpentinized peridotites from the Torishima Seamount, with depleted light REE concentration ([La/Sm]N =0.7). All the serpentinized peridotites from these four fore-arc seamounts show strong enrichment in fluid-mobile and lithophile elements (U, Pb, Sr and Li). The geochemical signature of the serpentinized peridotites from the seamounts in the Izu-Bonin-Mariana fore-arc region could be

  7. Deposits, petrology and mechanism of the 2010-2013 eruption of Kizimen volcano in Kamchatka, Russia

    Science.gov (United States)

    Auer, A.; Belousov, A.; Belousova, M.

    2018-04-01

    Kizimen volcano in Kamchatka is well known as a source of highly heterogeneous poorly mingled magmas ranging from dacites to basaltic andesites. In 2010-2013, the volcano produced its first historical magmatic eruption with the deposition of 0.27 km3 of block and ash pyroclastic flows accompanied by slow extrusion of a 200-m-thick, highly viscous (1010-1011 Pa s) block lava flow with a volume of 0.3 km3. The total volume of erupted magma comprised approximately 0.4 km3 DRE. We provide description of the eruption chronology, as well as the lithology and petrology of eruptive products. The erupted material is represented by banded dacite and high-silica andesite. The dacitic magma was formed during a long dormancy after the previous magmatic eruption several hundred years ago with mineral compositions indicating average pre-eruptive temperatures of 810 °C, fO2 of 0.9-1.6 log units above the nickel-nickel oxide (NNO) buffer and shallow crustal storage conditions at 123 MPa. The silica-rich andesite represents a hybrid magma, which shows signs of recent thermal and compositional disequilibrium. We suggest that the hybrid magma started to form in 1963 when a swarm of deep earthquakes indicated an input of mafic magma from depth into the 6-11-km-deep silicic magma chamber. It took the following 46 years until the magma filling the chamber reached an eruptible state. Poor mingling of the two melts is attributed to its unusually high viscosity that could be associated with the pre-eruptive long-term leakage of volatiles from the chamber through a regional tectonic fault. Our investigations have shown that shallow magma chambers of dormant volcanoes demonstrating strong persistent fumarolic activity can contain highly viscous, degassed magma of evolved composition. Reactivation of such magma chambers by injection of basic magma takes a long time (several decades). Thus, eruption forecasts at such volcanoes should include a possibility of long time lag between a swarm of

  8. Petrology of the axial ridge of the Mariana Trough backarc spreading center

    International Nuclear Information System (INIS)

    Hawkins, J.W.; Lonsdale, P.F.; Macdougall, J.D.; Volpe, A.M.

    1990-01-01

    The axial ridge of the Mariana Trough backarc basin, between 17deg40'N and 18deg30'N rises as much as 1 km above the floor of a 10-15 km wide rift valley. Physiographic segmentation, with minor ridge offsets and overlaps, coincides with a petrologic segmentation seen in trace element and isotope chemistry. Analyses of 239 glass and 40 aphyric basalt samples, collected with ALVIN and by dredging, show that the axial ridge is formed largely of (olivine) hypersthene-normative tholeiitic basalt. About half of these are enriched in both LIL elements and volatiles, but are depleted in HFS elements like other rocks found throughout much of the Mariana Trough. The LIL enrichments distinguish these rocks from N-MORB even though Nd and Sr isotope ratios indicate that much of the crust formed from a source similar to that for N-MORB. In addition to LIL-enriched basalt there is LIL depleted basalts even more closely resembling N-MORB in major and trace elements as well as Sr, Nd and Pb isotopes. Both basalt varieties have higher Al and lower total Fe than MORB at equivalent Mg level. Mg ranges from relatively ''primitive'' (e.g. Mg 65-70) to more highly fractionated (e.g. Mg 45-50). Highest parts of the axial ridge are capped by pinnacles with elongated pillows of basaltic andesite (e.g. 52-56%) SiO 2 . These are due to extreme fractional crystallization of basalts forming the axial ridge. Active hydrothermal vents with chimneys and mats of opaline silica, barite, sphalerite and lesser amounts of pyrite, chalcopyrite and galena formed near these silicic rocks. The vents are surrounded by distinctive vent animals, polychaete worms, crabs and barnacles. Isotope data indicate that the Mariana Trough crust was derived from a heterogeneous source including mantle resembling the MORB-source and an ''arc-source'' component. The latter was depleted in HFS elements in previous melting events and later modified by addition of H 2 O and LIL elements. (orig.)

  9. Petrology, Palynology, and Geochemistry of Gray Hawk Coal (Early Pennsylvanian, Langsettian in Eastern Kentucky, USA

    Directory of Open Access Journals (Sweden)

    James C. Hower

    2015-09-01

    Full Text Available This study presents recently collected data examining the organic petrology, palynology, mineralogy and geochemistry of the Gray Hawk coal bed. From the Early Pennsylvanian, Langsettian substage, Gray Hawk coal has been mined near the western edge of the eastern Kentucky portion of the Central Appalachian coalfield. While the coal is thin, rarely more than 0.5-m thick, it has a low-ash yield and a low-S content, making it an important local resource. The Gray Hawk coal palynology is dominated by Lycospora spp., and contains a diverse spectrum of small lycopods, tree ferns, small ferns, calamites, and gymnosperms. The maceral assemblages show an abundance of collotelinite, telinite, vitrodetrinite, fusinite, and semifusinite. Fecal pellet-derived macrinite, albeit with more compaction than is typically seen in younger coals, was observed in the Gray Hawk coal. The minerals in the coal are dominated by clay minerals (e.g., kaolinite, mixed-layer illite/smectite, illite, and to a lesser extent, pyrite, quartz, and iron III hydroxyl-sulfate, along with traces of chlorite, and in some cases, jarosite, szomolnokite, anatase, and calcite. The clay minerals are of authigenic and detrital origins. The occurrence of anatase as cell-fillings also indicates an authigenic origin. With the exception of Ge and As, which are slightly enriched in the coals, the concentrations of other trace elements are either close to or much lower than the averages for world hard coals. Arsenic and Hg are also enriched in the top bench of the coal and probably occur in pyrite. The elemental associations (e.g., Al2O3/TiO2, Cr/Th-Sc/Th indicate a sediment-source region with intermediate and felsic compositions. Rare metals, including Ga, rare earth elements and Ge, are highly enriched in the coal ashes, and the Gray Hawk coals have a great potential for industrial use of these metals. The rare earth elements in the samples are weakly fractionated or are characterized by heavy

  10. A fossil subduction zone in the East Greenland Caledonides revealed by a Receiver Function analysis

    DEFF Research Database (Denmark)

    Schiffer, Christian; Jacobsen, B. H.; Balling, N.

    Subsequent to their formation the East Greenland and Scandinavian Caledonides formed a major coherent mountain range. The understanding of the European Caledonides therefore naturally involves also the East Greenland Caledonides. The present-day topography and crustal and upper mantle structure i...

  11. Flow units classification for geostatisitical three-dimensional modeling of a non-marine sandstone reservoir: A case study from the Paleocene Funing Formation of the Gaoji Oilfield, east China

    Science.gov (United States)

    Zhang, Penghui; Zhang, Jinliang; Wang, Jinkai; Li, Ming; Liang, Jie; Wu, Yingli

    2018-05-01

    Flow units classification can be used in reservoir characterization. In addition, characterizing the reservoir interval into flow units is an effective way to simulate the reservoir. Paraflow units (PFUs), the second level of flow units, are used to estimate the spatial distribution of continental clastic reservoirs at the detailed reservoir description stage. In this study, we investigate a nonroutine methodology to predict the external and internal distribution of PFUs. The methodology outlined enables the classification of PFUs using sandstone core samples and log data. The relationships obtained between porosity, permeability and pore throat aperture radii (r35) values were established for core and log data obtained from 26 wells from the Funing Formation, Gaoji Oilfield, Subei Basin, China. The present study refines predicted PFUs at logged (0.125-m) intervals, whose scale is much smaller than routine methods. Meanwhile, three-dimensional models are built using sequential indicator simulation to characterize PFUs in wells. Four distinct PFUs are classified and located based on the statistical methodology of cluster analysis, and each PFU has different seepage ability. The results of this study demonstrate the obtained models are able to quantify reservoir heterogeneity. Due to different petrophysical characteristics and seepage ability, PFUs have a significant impact on the distribution of the remaining oil. Considering these allows a more accurate understanding of reservoir quality, especially within non-marine sandstone reservoirs.

  12. Drugs in East Germany.

    Science.gov (United States)

    Dressler, J; Müller, E

    1997-09-01

    Germany was divided into two parts after World War II. The closed border and a nonconvertible currency in the Eastern part were the factors that did not allow a drug market to develop. Alcohol and medicaments were used as substitute drugs. Since Germany was reunified 5 years ago, there are now the same conditions prevailing for the procurement and sale of drugs in East Germany as there are in the Western German states. This report describes the current state of drug traffic, especially in Saxony, under the new social conditions.

  13. Upper mantle and crustal structure of the East Greenland Caledonides

    DEFF Research Database (Denmark)

    Schiffer, Christian; Balling, N.; Jacobsen, B. H.

    The East Greenland and Scandinavian Caledonides once formed a major coherent mountain range, as a consequence of the collision of the continents of Laurentia and Baltica. The crustal and upper mantle structure was furthermore influenced by several geodynamic processes leading to the formation of ...

  14. East African governments' responses to high cereal prices

    NARCIS (Netherlands)

    Meijerink, G.W.; Roza, P.; Berkum, van S.

    2009-01-01

    This study analyses the responses of governments in four East African countries (Kenya, Tanzania, Uganda and Ethiopia) with respect to price formation and price transmission in the cereal sector. All four countries were confronted with high cereal prices in 2008. Government policies applied largely

  15. Climatic variability of east Malaysia

    International Nuclear Information System (INIS)

    Camerlengo, A.L.; Saadon, M.N.; Awang, M.; Somchit, H.; Rang, L.Y.

    2001-01-01

    The objective of this paper is to learn the variability of atmospheric pressure, relative humidity and insolation in East Malaysia. The main results of our study are: (1) a gentle pressure gradient is observed at the east coast in the boreal winter, (2) smaller atmospheric pressure values are noted during the first inter-monsoon period all across East Malaysia, (3) lesser insolation values are observed in Sarawak and at the east coast during the boreal winter as compared to the boreal summer, and (4) a poleward increase of insolation is registered. (author)

  16. Ore-forming adakitic porphyry produced by fractional crystallization of oxidized basaltic magmas in a subcrustal chamber (Jiamate, East Junggar, NW China)

    Science.gov (United States)

    Hong, Tao; Xu, Xing-Wang; Gao, Jun; Peters, Stephen; Zhang, Di; Jielili, Reyaniguli; Xiang, Peng; Li, Hao; Wu, Chu; You, Jun; Liu, Jie; Ke, Qiang

    2018-01-01

    Adakitic intrusions are supposed to have a close genetic and spatial relationship to porphyry Cu deposits. However, the genesis of adakitic intrusions is still under dispute. Here, we describe newly discovered intrusive complex rocks, which are composed of ore-bearing, layered magnetite-bearing gabbroic and adakitic rocks in Jiamate, East Junggar, NW China. These Jiamate Complex intrusions have diagnostic petrologic, geochronologic and geochemical signatures that indicate they were all generated from the same oxidized precursor magma source. Additionally, these layered rocks underwent the same fractional crystallization process as the ore-bearing adakitic rocks in the adjacent Kalaxiangar Porphyry Cu Belt (KPCB) in an oceanic island arc (OIA) setting. The rocks studied for this paper include layered magnetite-bearing gabbroic intrusive rocks that contain: (1) gradual contact changes between lithological units of mafic and intermediate rocks, (2) geochemical signatures that are the same as those found in oceanic island arc (OIA) rocks, (3) typical adakitic geochemistry, and (4) similar characteristics and apparent fractional crystallization relationships of ultra-basic to basic rocks to those in the nearby Beitashan Formation and to ore-bearing adakitic rocks in the KPCB. They also display similar zircon U-Pb and zircon Hf model ages.The Jiamate Complex intrusions contain intergrowths of magnetite and layered gabbro, and the intermediate-acidic intrusions of the Complex display typical adakitic affinities. Moreover, in conjunction with previously published geochronological and geochemistry data of the mafic rocks in the Beitashan Formation and in the KPCB area, additional data generated for the Jiamate Complex intrusions rocks indicate that they were formed from fractional crystallization processes. The Jiamate Complex intrusions most likely were derived from a metasomatized mantle wedge that was underplated at the root of the Saur oceanic island arc (Saur OIA). The

  17. Ore-forming adakitic porphyry produced by fractional crystallization of oxidized basaltic magmas in a subcrustal chamber (Jiamate, East Junggar, NW China)

    Science.gov (United States)

    Hong, Tao; Xu, Xing-Wang; Gao, Jun; Peters, Stephen G.; Zhang, Di; Jielili, Reyaniguli; Xiang, Peng; Li, Hao; Wu, Chu; You, Jun; Liu, Jie; Ke, Qiang

    2018-01-01

    Adakitic intrusions are supposed to have a close genetic and spatial relationship to porphyry Cu deposits. However, the genesis of adakitic intrusions is still under dispute. Here, we describe newly discovered intrusive complex rocks, which are composed of ore-bearing, layered magnetite-bearing gabbroic and adakitic rocks in Jiamate, East Junggar, NW China. These Jiamate Complex intrusions have diagnostic petrologic, geochronologic and geochemical signatures that indicate they were all generated from the same oxidized precursor magma source. Additionally, these layered rocks underwent the same fractional crystallization process as the ore-bearing adakitic rocks in the adjacent Kalaxiangar Porphyry Cu Belt (KPCB) in an oceanic island arc (OIA) setting. The rocks studied for this paper include layered magnetite-bearing gabbroic intrusive rocks that contain: (1) gradual contact changes between lithological units of mafic and intermediate rocks, (2) geochemical signatures that are the same as those found in oceanic island arc (OIA) rocks, (3) typical adakitic geochemistry, and (4) similar characteristics and apparent fractional crystallization relationships of ultra-basic to basic rocks to those in the nearby Beitashan Formation and to ore-bearing adakitic rocks in the KPCB. They also display similar zircon U-Pb and zircon Hf model ages. The Jiamate Complex intrusions contain intergrowths of magnetite and layered gabbro, and the intermediate-acidic intrusions of the Complex display typical adakitic affinities. Moreover, in conjunction with previously published geochronological and geochemistry data of the mafic rocks in the Beitashan Formation and in the KPCB area, additional data generated for the Jiamate Complex intrusions rocks indicate that they were formed from fractional crystallization processes. The Jiamate Complex intrusions most likely were derived from a metasomatized mantle wedge that was underplated at the root of the Saur oceanic island arc (Saur OIA

  18. Petrology and geochronology of metamorphosed volcanic rocks and a middle Cretaceous volcanic neck in the east-central Sierra Nevada, California.

    Science.gov (United States)

    Kistler, R.W.; Swanson, S.E.

    1981-01-01

    Metamorphosed Mesozoic volcanic rocks from the E-central Sierra Nevada range in composition from basalt to rhyolite and have ages, based on whole rock Rb-Sr and U-Pb zircon dating, of about 237- 224, 185, 163, 134, and 100Ma. The major plutons of the batholith in this area are of Triassic (215-200Ma) and Cretaceous (94-80Ma) ages. Initial 87Sr/86Sr values for the metamorphosed volcanic rocks of the area are in the range from 0.7042 to 0.7058 and are generally different from the values for the surrounding batholithic rocks (0.7056-0.7066). A circular, zoned granitic pluton, with an outcrop area of 2.5km2, similar in appearance to a ring dike complex, was apparently a conduit for some or possibly all of the middle-Cretaceous metamorphosed volcanic rocks exposed about 5km to the S in the western part of the Ritter Range. Samples from the metamorphosed volcanic rocks and the pluton yield a Rb/Sr whole rock isochron age of 99.9+ or -2.2Ma with an intitial 87Sr/86Sr of 0.7048+ or -0.00001. Major element variation diagrams of the pluton and volcanic rocks define coincident compositional trends. The ages of volcanic events relative to the ages of the major intrusive epochs and the major element and isotopic compositions of the volcanic rocks relative to the major plutons indicate that the volcanic rocks are not simply or directly related to the major plutons in the Sierra Nevada. -from Authors

  19. Petrology and geochemistry of intrusive rocks in Some-Ahani and Ferezneh prospect areas, east of Sangan mine, Khaf (Southeast of Mashhad

    Directory of Open Access Journals (Sweden)

    Nazi Mazhari

    2017-03-01

    Full Text Available The Some-Ahani and Ferezneh prospect areas are two of the eastern anomalies ofKhaf’s Sangan iron mine in Khorasan Razavi province. Biotite monzonite porphyry andbiotite syenogranite Tertiary plutons occurred in the area of study. Due to the severe alteration of biotite monzonite porphyry intrusion, geochemical studies have beenfocused on the biotite syenogranite. It is chemically peraluminous, moderate to highpotassic and magnesian and its tectonic setting is of post orogenic. In both A-typegranites and in differentiated peralkaline I-type granitic rocks: negative Eu anomaly,mild enrichment of LREE, positive, relatively flat HREE pattern, negative anomalies ofBa, Sr, La, Ce, Ti, and large amount of Ga (16- 24 ppm are the same. On the basis ofmajor oxide values and SiO2 vs. FeOt/MgO ratio, the prospect area samples fall in therange of I-type granites. Variations in the minor and trace elements in all samplesindicate fractional crystallization in separation of plagioclase, alkali feldspar and biotite,generated by fractional crystallization from an I-type granitic magma poor in P. Increasein HFS elements such as Ga and Nb is associated with the differentiation of thesegranites. Comparison of the intrusions studied with Bermani and Sarkhar rocks insoutheast Sangan shows that variations in the major, minor and rare earth elements aresimilar to each other and to those of I-type granites, which can be differentiated by various degrees of partial melting of andesite and dacite protolith or are produced by atwo-stage process of remelting intermediate rocks.

  20. Petrological evolution of subducted rodingite from seafloor metamorphism to dehydration of enclosing antigorite-serpentinite (Cerro del Almirez massif, southern Spain)

    Science.gov (United States)

    Laborda-López, Casto; López Sánchez-Vizcaíno, Vicente; Marchesi, Claudio; Gómez-Pugnaire, María Teresa; Garrido, Carlos J.; Jabaloy-Sánchez, Antonio; Padrón-Navarta, José Alberto

    2016-04-01

    . Close to the contact with the blackwall, antigorite-serpentinite is very rich in diopside, olivine and Ti-clinohumite. In this study we present a thermodynamic model of phase relationships in rodingites and transitional blackwalls during their metamorphic history. We mainly aim to establish the evolution of P-T conditions experienced by metarodingites during subduction and the influence of fluids in the formation of mineral assemblages at different metamorphic stages. REFERENCES Padrón-Navarta, J.A., López Sánchez-Vizcaíno, V., Garrido, C.J., Gómez-Pugnaire, M.T., (2011): Metamorphic record of high-pressure dehydration of antigorite serpentinite to chlorite harzburgite in a subduction setting (Cerro Del Almirez, Nevado-Filábride Complex, Southern Spain). Journal of Petrology, 52, 2047-2078.

  1. Petrological systematics of mid-ocean ridge basalts: Constraints on melt generation beneath ocean ridges

    Science.gov (United States)

    Langmuir, Charles H.; Klein, Emily M.; Plank, Terry

    Mid-ocean ridge basalts (MORB) are a consequence of pressure-release melting beneath ocean ridges, and contain much information concerning melt formation, melt migration and heterogeneity within the upper mantle. MORB major element chemical systematics can be divided into global and local aspects, once they have been corrected for low pressure fractionation and interlaboratory biases. Regional average compositions for ridges unaffected by hot spots ("normal" ridges) can be used to define the global correlations among normalized Na2O, FeO, TiO2 and SiO2 contents, CaO/Al2O3 ratios, axial depth and crustal thickness. Back-arc basins show similar correlations, but are offset to lower FeO and TiO2 contents. Some hot spots, such as the Azores and Galapagos, disrupt the systematics of nearby ridges and have the opposite relationships between FeO, Na2O and depth over distances of 1000 km. Local variations in basalt chemistry from slow- and fast-spreading ridges are distinct from one another. On slow-spreading ridges, correlations among the elements cross the global vector of variability at a high angle. On the fast-spreading East Pacific Rise (EPR), correlations among the elements are distinct from both global and slow-spreading compositional vectors, and involve two components of variation. Spreading rate does not control the global correlations, but influences the standard deviations of axial depth, crustal thickness, and MgO contents of basalts. Global correlations are not found in very incompatible trace elements, even for samples far from hot spots. Moderately compatible trace elements for normal ridges, however, correlate with the major elements. Trace element systematics are significantly different for the EPR and the mid-Atlantic Ridge (MAR). Normal portions of the MAR are very depleted in REE, with little variability; hot spots cause large long wavelength variations in REE abundances. Normal EPR basalts are significantly more enriched than MAR basalts from normal

  2. Composition of uppermost mantle beneath the Northern Fennoscandia - numerical modeling and petrological interpretation

    Science.gov (United States)

    Virshylo, Ivan; Kozlovskaya, Elena; Prodaivoda, George; Silvennoinen, Hanna

    2013-04-01

    Studying of the uppermost mantle beneath the northern Fennoscandia is based on the data of the POLENET/LAPNET passive seismic array. Firstly, arrivals of P-waves of teleseismic events were inverted into P-wave velocity model using non-linear tomography (Silvennoinen et al., in preparation). The second stage was numerical petrological interpretation of referred above velocity model. This study presents estimation of mineralogical composition of the uppermost mantle as a result of numerical modeling. There are many studies concerning calculation of seismic velocities for polymineral media under high pressure and temperature conditions (Afonso, Fernàndez, Ranalli, Griffin, & Connolly, 2008; Fullea et al., 2009; Hacker, 2004; Xu, Lithgow-Bertelloni, Stixrude, & Ritsema, 2008). The elastic properties under high pressure and temperature (PT) conditions were modelled using the expanded Hook's law - Duhamel-Neumann equation, which allows computation of thermoelastic strains. Furthermore, we used a matrix model with multi-component inclusions that has no any restrictions on shape, orientation or concentration of inclusions. Stochastic method of conditional moment with computation scheme of Mori-Tanaka (Prodaivoda, Khoroshun, Nazarenko, & Vyzhva, 2000) is applied instead of traditional Voigt-Reuss-Hill and Hashin-Shtrikman equations. We developed software for both forward and inverse problem calculation. Inverse algorithm uses methods of global non-linear optimization. We prefer a "model-based" approach for ill-posed problem, which means that the problem is solved using geological and geophysical constraints for each parameter of a priori and final models. Additionally, we are checking at least several different hypothesis explaining how it is possible to get the solution with good fit to the observed data. If the a priori model is close to the real medium, the nearest solution would be found by the inversion. Otherwise, the global optimization is searching inside the

  3. The Danish East India Company

    DEFF Research Database (Denmark)

    Sørensen, Karsten Engsig

    2005-01-01

    The article analysis the first Danish East India Company incorporated in 1616, which was the first Danish Stock Company and which has impacts even on modern Danish company la......The article analysis the first Danish East India Company incorporated in 1616, which was the first Danish Stock Company and which has impacts even on modern Danish company la...

  4. Petrologic and petrophysical evaluation of the Dallas Center Structure, Iowa, for compressed air energy storage in the Mount Simon Sandstone.

    Energy Technology Data Exchange (ETDEWEB)

    Heath, Jason E.; Bauer, Stephen J.; Broome, Scott Thomas; Dewers, Thomas A.; Rodriguez, Mark A

    2013-03-01

    The Iowa Stored Energy Plant Agency selected a geologic structure at Dallas Center, Iowa, for evaluation of subsurface compressed air energy storage. The site was rejected due to lower-than-expected and heterogeneous permeability of the target reservoir, lower-than-desired porosity, and small reservoir volume. In an initial feasibility study, permeability and porosity distributions of flow units for the nearby Redfield gas storage field were applied as analogue values for numerical modeling of the Dallas Center Structure. These reservoir data, coupled with an optimistic reservoir volume, produced favorable results. However, it was determined that the Dallas Center Structure cannot be simplified to four zones of high, uniform permeabilities. Updated modeling using field and core data for the site provided unfavorable results for air fill-up. This report presents Sandia National Laboratories petrologic and petrophysical analysis of the Dallas Center Structure that aids in understanding why the site was not suitable for gas storage.

  5. Magmatic and petrologic evolution of the mesozvic vulcanic acid rocks from Piraju-Ourinhos region (SP-PR)

    International Nuclear Information System (INIS)

    Raposo, M.I.B.

    1987-01-01

    This work presents the result of geological, petrological and geochemical studies, on the volcanic rocks from Piraju-Ourinhos region, SP, with special emphasis on the rocks. A geological mapping was carried out by using images from Landsat satellite. Petrographic and chemical analyses have defined a suite represented by basic lithotype - tholeutic andesibasalt - with high TiO 2 , rich in incompable elements - mainly Sr, Zr, La, Ce, and Ba - and by acid lithotype - rhyolite - rhyodacite. k-Ar ages are determined in feldspar concentrated, and indicate an age of 133+- 4m,y, for the volcanic acid rocks. Determinations of Sr isotopes. In order to explain the genesis of Chapeco type acid magnas quantitative models were tested using both fractional Crystallization [pt

  6. Petrologic insights into basaltic volcanism at historically active Hawaiian volcanoes: Chapter 6 in Characteristics of Hawaiian volcanoes

    Science.gov (United States)

    Helz, Rosalind L.; Clague, David A.; Sisson, Thomas W.; Thornber, Carl R.; Poland, Michael P.; Takahashi, T. Jane; Landowski, Claire M.

    2014-01-01

    Study of the petrology of Hawaiian volcanoes, in particular the historically active volcanoes on the Island of Hawai‘i, has long been of worldwide scientific interest. When Dr. Thomas A. Jaggar, Jr., established the Hawaiian Volcano Observatory (HVO) in 1912, detailed observations on basaltic activity at Kīlauea and Mauna Loa volcanoes increased dramatically. The period from 1912 to 1958 saw a gradual increase in the collection and analysis of samples from the historical eruptions of Kīlauea and Mauna Loa and development of the concepts needed to evaluate them. In a classic 1955 paper, Howard Powers introduced the concepts of magnesia variation diagrams, to display basaltic compositions, and olivine-control lines, to distinguish between possibly comagmatic and clearly distinct basaltic lineages. In particular, he and others recognized that Kīlauea and Mauna Loa basalts must have different sources.

  7. Middle East gas

    International Nuclear Information System (INIS)

    Thomas, V.

    2001-01-01

    Despite the significant contribution of the Middle East countries of Bahrain, Iran, Iraq, Kuwait, Qatar, Saudi Arabia and the United Arab Emirates in the Arabia Gulf to the world's oil output, they are placing increasing emphasis on natural gas as a source of exports and to fuel domestic economic growth. The region accounts for 35% of the world's proven gas resource base, with Iran and Qatar holding major reserves. The region is becoming increasingly important in global liquefied natural gas (LNG) trade and details of key LNG projects and the major players in this area are given; a key advantage is the region's position between the two main markets - the Asia Pacific and the Atlantic Basin. Brief details are also given of gas pipeline projects and gas-to-liquid (GTL) projects in the region

  8. Incorporating Problem-Based Learning Into A Petrology Course Through A Research Project In The Local Northern Sierra Nevada

    Science.gov (United States)

    Aird, H. M.

    2016-12-01

    A research project into the local petrology was integrated into the Spring 2016 Petrology and Optical Mineralogy course at California State University, Chico. This is a required majors course, typically taken during spring of the junior year, with an enrollment of 10-20 students. Since the labs for this course have a strong focus on petrography, a research project was introduced to give students experience in using a multi-faceted approach to investigate a problem. In many cases, this is their first taste of research. During the first week of the Spring 2016 class, students were introduced to the research question: In the broader context of Californian tectonic history, are the Bucks Lake and Grizzly plutons of the northern Sierra Nevada petrogenetically related? With faculty guidance over the course of the semester, students carried out fieldwork and sampling, lithologic description, selection of the best samples for further analysis, thin section production, petrographic description, and analysis and interpretation of published geochemical data. Research activities were strategically scheduled within the course framework such that students were academically prepared to carry out each task. Each student was responsible for generating all the data for one sample, and data were then collated as a class, so students wrote their individual final reports using all the data collected by the class. Careful scaffolding of writing assignments throughout the semester guided students through the preparation of an academic-style scientific report, while allowing for repeated feedback on their writing style and content. In mid-May, the class presented a group poster at the College of Natural Sciences annual poster symposium, and were awarded `Best Student Class Project' by the judges. Anecdotal student feedback indicated they highly valued the research experience and some were inspired to pursue individual undergraduate research projects under faculty supervision.

  9. East Asian Studies of Tropospheric Aerosols and their Impact on Regional Climate (EAST -AIRC): An overview

    Science.gov (United States)

    Zhangqing, Li; Li, C.; Chen, H.; Tsay, S.-C.; Holben, B.; Huang, J.; Li, B.; Maring, H.; Qian, Y.; Shi, G.; hide

    2011-01-01

    As the most populated region of the world, Asia is a major source of aerosols with potential large impact over vast downstream areas, Papers published in this special section describe the variety of aerosols observed in China and their effects and interactions with the regional climate as part of the East Asian Study of Tropospheric Aerosols and their Impact on Regional Climate (EAST-AIRC), The majority of the papers are based on analyses of observations made under three field projects, namely, the Atmospheric Radiation Measurements (ARM) Mobile Facility mission in China (AMF-China), the East Asian Study of Tropospheric Aerosols: An International Regional Experiment (EAST-AIRE), and the Atmospheric Aerosols of China and their Climate Effects (AACCE), The former two are U,S,-China collaborative projects, and the latter is a part of the China's National Basic Research program (or often referred to as "973 project"), Routine meteorological data of China are also employed in some studies, The wealth of general and speCIalized measurements lead to extensive and close-up investigations of the optical, physical, and chemical properties of anthropogenic, natural, and mixed aerosols; their sources, formation, and transport mechanisms; horizontal, vertical, and temporal variations; direct and indirect effects; and interactions with the East Asian monsoon system, Particular efforts are made to advance our understanding of the mixing and interaction between dust and anthropogenic pollutants during transport. Several modeling studies were carried out to simulate aerosol impact on radiation budget, temperature, precipitation, wind and atmospheric circulation, fog, etc, In addition, impacts of the Asian monsoon system on aerosol loading are also simulated.

  10. The East African rift system

    Science.gov (United States)

    Chorowicz, Jean

    2005-10-01

    This overview paper considers the East African rift system (EARS) as an intra-continental ridge system, comprising an axial rift. It describes the structural organization in three branches, the overall morphology, lithospheric cross-sections, the morphotectonics, the main tectonic features—with emphasis on the tension fractures—and volcanism in its relationships with the tectonics. The most characteristic features in the EARS are narrow elongate zones of thinned continental lithosphere related to asthenospheric intrusions in the upper mantle. This hidden part of the rift structure is expressed on the surface by thermal uplift of the rift shoulders. The graben valleys and basins are organized over a major failure in the lithospheric mantle, and in the crust comprise a major border fault, linked in depth to a low angle detachment fault, inducing asymmetric roll-over pattern, eventually accompanied by smaller normal faulting and tilted blocks. Considering the kinematics, divergent movements caused the continent to split along lines of preexisting lithospheric weaknesses marked by ancient tectonic patterns that focus the extensional strain. The hypothesis favored here is SE-ward relative divergent drifting of a not yet well individualized Somalian plate, a model in agreement with the existence of NW-striking transform and transfer zones. The East African rift system comprises a unique succession of graben basins linked and segmented by intracontinental transform, transfer and accommodation zones. In an attempt to make a point on the rift system evolution through time and space, it is clear that the role of plume impacts is determinant. The main phenomenon is formation of domes related to plume effect, weakening the lithosphere and, long after, failure inducing focused upper mantle thinning, asthenospheric intrusion and related thermal uplift of shoulders. The plume that had formed first at around 30 Ma was not in the Afar but likely in Lake Tana region (Ethiopia

  11. The Jurassic of North-East Greenland: Jurassic dinoflagellate cysts from Hochstetter Forland, North-East Greenland

    Directory of Open Access Journals (Sweden)

    Piasecki, Stefan

    2004-11-01

    Full Text Available Three sections in Hochstetter Forland, North-East Greenland, referred to the Jurassic Payer Dal and Bernbjerg Formations, have been analysed for dinoflagellate cysts. The dinoflagellate cysts,new finds of ammonites and previously recorded marine faunas form the basis for improved dating of the succession. The basal strata of the Payer Dal Formation at Kulhus is here dated as Late Callovian, Peltoceras athleta Chronozone, based on the presence of relatively abundant Limbicysta bjaerkei, Mendicodinium groenlandicum, Rhychoniopsis cladophora and Tubotuberella dangeardii in an otherwise poor Upper Callovian dinoflagellate assemblage. Ammoniteshave not been recorded from these strata. The upper Payer Dal Formation at Agnetesøelven is dated as Late Oxfordian, Amoeboceras glosense – Amoeboceras serratum Chronozones, based onthe presence of Sciniodinium crystallinum, together with Cribroperidinium granuligera and Stephanelytron sp. The age is in accordance with ammonites present in the uppermost part ofthe formation at Søndre Muslingebjerg. New ammonites in the Bernbjerg Formation at Agnetesøelven together with dinoflagellate cysts indicate an earliest Kimmeridgian age, Raseniacymodoce and Aulacostephanoides mutabilis Chronozones.The Upper Callovian dinoflagellate cysts from Hochstetter Forland belong to a local brackish to marginal marine assemblage, which only allows a fairly broad correlation to coeval assemblagesin central East Greenland. In contrast, the Oxfordian and Kimmeridgian assemblages are fully marine and can be correlated from Milne Land in central East Greenland via Hochstetter Forland to Peary Land in eastern North Greenland.

  12. Experimental and petrological constraints on long-term magma dynamics and post-climactic eruptions at the Cerro Galán caldera system, NW Argentina

    Science.gov (United States)

    Grocke, Stephanie B.; Andrews, Benjamin J.; de Silva, Shanaka L.

    2017-11-01

    Cerro Galán in NW Argentina records > 3.5 Myr of magmatic evolution of a major resurgent caldera complex. Beginning at 5.72 Ma, nine rhyodacitic ignimbrites (68-71 wt% SiO2) with a combined minimum volume of > 1200 km3 (Dense Rock Equivalent; DRE) have been erupted. The youngest of those ignimbrites is the eponymous, geochemically homogenous, caldera-forming 2.08 ± 0.02 Ma Cerro Galán Ignimbrite (CGI; > 630 km3 DRE). Following this climactic supereruption, structural and magmatic resurgence led to the formation of a resurgent dome and post-climactic lava domes and their associated pyroclastic deposits. A clear transition from amphibole to sanidine-bearing magmas occurred during the evolution of Cerro Galán and is inferred to represent a shallowing of the magma system. We test this hypothesis here using experimental phase equilibria. We conducted a series of phase equilibria experiments on the post-climactic dome lithologies under H2O-saturated conditions using cold seal Waspaloy pressure vessels with an intrinsic log fO2 of NNO + 1 ± 0.5 across a temperature-pressure range of 750-900 °C and 50-200 MPa (PH2O = Ptotal), respectively. Petrologic and geochemical analysis of the post-climactic lithologies shows that the natural phase assemblage (plagioclase + quartz + biotite + sanidine + Fe-Ti oxides ± apatite ± zircon) is stable at history of Cerro Galán is informed through a detailed investigation of the textural differences among the post-climactic dome lithologies, and a comparison of those textures with previously published decompression experiments. These suggest that the highly vesiculated, pumiceous clasts with rare microlites represent magma stored within the core of the lava dome that decompressed relatively rapidly (0.003-0.0003 MPa s-1) and evolved via closed system degassing. Resulting over-pressure of the dome may have triggered superficial explosion. In contrast, dense clasts with abundant crystalline silica precipitates represent more typical

  13. Geology and petrology of the Woods Mountains Volcanic Center, southeastern California: Implications for the genesis of peralkaline rhyolite ash flow tuffs

    Science.gov (United States)

    McCurry, Michael

    1988-12-01

    The Woods Mountains Volcanic Center is a middle Miocene silicic caldera complex located at the transition from the northern to the southern Basin and Range provinces of the western United States. It consists of a trachyte-trachydacite-rhyolite-peralkaline rhyolite association of lava flows, domes, plugs, pyroclastic rocks, and epiclastic breccia. Volcanism began at about 16.4 Ma, near the end of a local resurgence of felsic to intermediate magmatism and associated crustal extension. Numerous metaluminous high-K trachyte, trachydacite, and rhyolite lava flows, domes, and pyroclastic deposits accumulated from vents scattered over an area of 200 km2 forming a broad volcanic field with an initial volume of about 10 km3. At 15.8 Ma, about 80 km3 of metaluminous to mildly peralkaline high-K rhyolite ash flows were erupted from vents in the western part of fhe field in three closely spaced pulses, resulting in the formation of a trap door caldera 10 km in diameter. The ash flows formed the Wild Horse Mesa Tuff, a compositionally zoned ash flow sheet that originally covered an area of about 600 km2 to a maximum thickness of at least 320 m. High-K trachyte pumice lapilli, some of which are intimately banded with rhyolite, were produced late in the two later eruptions, Intracaldera volcanism from widely distributed vents rapidly filled the caldera with about 10 km3 of high-K, mildly peralkaline, high-silica rhyolite lava flows and pyroclastic deposits. These are interlayered with breccia derived from the caldera scarp. They are intruded by numerous compositionally similar plugs, some of which structurally uplifted and fractured the center of the caldera. The center evolved above a high-K trachyte magma chamber about 10 km in diameter that had developed and differentiated within the upper crust at about 15.8 Ma. Petrological, geochemical, and geophysical data are consistent with the idea that a cap of peralkaline rhyolite magma formed within the trachyte chamber as a result

  14. Continental lithosphere of the Arabian Plate: A geologic, petrologic, and geophysical synthesis

    Science.gov (United States)

    Stern, Robert J.; Johnson, Peter

    2010-07-01

    The Arabian Plate originated ˜ 25 Ma ago by rifting of NE Africa to form the Gulf of Aden and Red Sea. It is one of the smaller and younger of the Earth's lithospheric plates. The upper part of its crust consists of crystalline Precambrian basement, Phanerozoic sedimentary cover as much as 10 km thick, and Cenozoic flood basalt (harrat). The distribution of these rocks and variations in elevation across the Plate cause a pronounced geologic and topographic asymmetry, with extensive basement exposures (the Arabian Shield) and elevations of as much as 3000 m in the west, and a Phanerozoic succession (Arabian Platform) that thickens, and a surface that descends to sea level, eastward between the Shield and the northeastern margin of the Plate. This tilt in the Plate is partly the result of marginal uplift during rifting in the south and west, and loading during collision with, and subduction beneath, the Eurasian Plate in the northeast. But a variety of evidence suggests that the asymmetry also reflects a fundamental crustal and mantle heterogeneity in the Plate that dates from Neoproterozoic time when the crust formed. The bulk of the Plate's upper crystalline crust is Neoproterozoic in age (1000-540 Ma) reflecting, in the west, a 300-million year process of continental crustal growth between ˜ 850 and 550 Ma represented by amalgamated juvenile magmatic arcs, post-amalgamation sedimentary and volcanic basins, and granitoid intrusions that make up as much as 50% of the Shield's surface. Locally, Archean and Paleoproterozoic rocks are structurally intercalated with the juvenile Neoproterozoic rocks in the southern and eastern parts of the Shield. The geologic dataset for the age, composition, and origin of the upper crust of the Plate in the east is smaller than the database for the Shield, and conclusions made about the crust in the east are correspondingly less definitive. In the absence of exposures, furthermore, nothing is known by direct observation about the

  15. Looking at the roots of the highest mountains: the lithospheric structure of the Himalaya-Tibet and the Zagros orogens. Results from a geophysical-petrological study

    Science.gov (United States)

    Tunini, L.; Jimenez-Munt, I.; Fernandez, M.; Villasenor, A.; Afonso, J. C.; Verges, J.

    2013-12-01

    The Himalaya-Tibet and Zagros orogens are the two most prominent mountain belts built by continental collision. They are part of a huge belt of Cenozoic age which runs from the Pyrenees to Burma. In its central sector, the collision with the southern margin of the Eurasian plate has resulted not only in the building of mountain ranges over the north-eastern edges of the Arabian and Indian plates but also in widespread deformation 1000-3000 km from the suture zones. Zagros and Himalaya-Tibet orogens share many geodynamic processes but at different rates, amount of convergence and stage of development. The study of their present-day structures provides new insights into their quasi coeval collisional event pointing out differences and similarities in the mountain building processes. We present 2D crust and upper mantle cross-sections down to 400 km depth, along four SW-NE trending profiles. Two profiles cross the Zagros Mountains, running from the Mesopotamian Foreland Basin up to the Alborz and Central Iran. Two other profiles run through the Himalaya-Tibetan orogen: the western transect crosses the western Himalaya, Tarim Basin, Tian Shan Mountains and Junggar Basin; the eastern transect runs from the Indian shield to the Beishan Basin, crossing the eastern Himalaya, Tibetan Plateau, Qaidam Basin and Qilian Mountains. We apply the LitMod-2D code which integrates potential fields (gravity and geoid), isostasy (elevation) and thermal (heat flow and temperature distribution) equations, and mantle petrology. The resulting crust and upper mantle structure is constrained by available data on elevation, Bouguer anomaly, geoid height, surface heat flow and seismic data including P- and S-wave tomography models. Our results show distinct deformation patterns between the crust and the lithospheric mantle beneath the Zagros and Himalaya-Tibetan orogens, indicating a strong strain partitioning in both areas. At crustal level, we found a thickening beneath the Zagros and the

  16. Adiabat_1ph 3.0 and the MAGMA website: educational and research tools for studying the petrology and geochemistry of plate margins

    Science.gov (United States)

    Antoshechkina, P. M.; Asimow, P. D.

    2010-12-01

    Adiabat_1ph is a menu-driven front-end to the MELTS, pMELTS and pHMELTS models of thermodynamic equilibrium in silicate systems. Its public release in late 2004 was described in a software brief in G3 (doi:10.1029/2004GC000816). The software package is available for Windows, MacOS X, and Linux and includes Perl scripts that, if desired, will allow almost complete automation of the calculation process. Adiabat_1ph 3.0 is scheduled for release in October 2010 and includes, for the first time, an option to double-click the run_adiabat.command script and to drag and drop file names from a browser (e.g. Explorer on Windows, Finder on Mac). This alternative mode of operation is particularly suited for teaching at undergraduate and graduate levels, as well as for quick, ad hoc, calculations for research purposes. The original method of invoking the program from the command line is retained for more intensive applications. Version 3.0 is the first to specifically target the Windows 7 and Snow Leopard platforms. The release also includes new features that are relevant to the study of plate margins. The Marianas Trough forms the southern part of the Izu-Bonin-Marianas (IBM) arc system, one of the chosen areas of focus for the MARGINS Subduction Factory initiative. Attempts to model the complicated hydrous fractionation trends observed in this region were the motivation for adding modified versions of the ‘reverse-fractionation’ and ‘amoeba’ routines (see doi:10.1016/S0012-821X(04)00058-5) into adiabat_1ph. The ‘amoeba’ scheme, which varies a trial parental melt composition until forward fractionation yields a specified target composition, has been extended so the best-fit liquid line of descent of a group of samples can be found. We have tested the adiabat_1ph versions using glass compositions from the 9N area of the East Pacific Rise and melt inclusions from the Siqueiros Fracture Zone (see Antoshechkina et al., this meeting). One of the first user requested

  17. East India Company Logbooks - Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This collection consists of images of 1,235 ship logbooks created during British East India Company voyages. Period of record 1786-1834, peaking in 1804. The...

  18. Nuclear power in East Asia

    International Nuclear Information System (INIS)

    Abelson, P.H.

    1996-01-01

    This editorial discusses the shifting dominance in the nuclear reactor technology from the USA to new leadership in East Asia. With the expanding economies and electricity demand, Design, construction and operation of a large number of nuclear power plants in east Asia will support nuclear engineers, technologist, manufacturing facilities, and potential weapons experts. In contrast, the cessation of construction of power reactors in the US is leading to deminished nuclear capabilities

  19. Petrology of the prehistoric lavas and dyke of the Barren Island ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    historic times, the eruptions that led to the formation of this volcanic island occurred mainly during prehistoric times. ... eruptions occurred from its centre, producing a. 250m high ... non-eruptive lateral landslide of the original cone or by vertical ...

  20. The Marbat metamorphic core-complex (Southern Arabian Peninsula) : reassessment of the evolution of a Neoproterozoic island-arc from petrological, geochemical and U-Pb zircon data

    OpenAIRE

    Barbey, P.; Denele, Y.; Paquette, J. L.; Berger, J.; Ganne, Jérôme; Roques, D.

    2018-01-01

    The Marbat basement (Sultanate of Oman) belongs to the Neoproterozoic accretion domain of the Arabian-Nubian shield. We present new geochronological, petrological and geochemical data as an extension of our previous study (Denele et al., 2017) re-interpreting this basement as a metamorphic core complex (MCC). We showed that this MCC consists of a metamorphic unit (Juffa complex) separated by an extensional detachment from a plutonic unit (Sadh complex and Tonalite plutons). Geochemical data s...

  1. ISSN 2073 ISSN 2073-9990 East Cent. East Cent. East Cent. Afr. J.

    African Journals Online (AJOL)

    DELL

    East and Central African Journal of Surgery. ... collaboration in the writing and editing of Surgical Care at the District Hospital, ... increasing availability of computers and huge developments in software technology such ... Emergency Surgery ...

  2. Subduction metamorphism in the Himalayan ultrahigh-pressure Tso Morari massif: An integrated geodynamic and petrological modelling approach

    Science.gov (United States)

    Palin, Richard M.; Reuber, Georg S.; White, Richard W.; Kaus, Boris J. P.; Weller, Owen M.

    2017-06-01

    The Tso Morari massif is one of only two regions where ultrahigh-pressure (UHP) metamorphism of subducted crust has been documented in the Himalayan Range. The tectonic evolution of the massif is enigmatic, as reported pressure estimates for peak metamorphism vary from ∼2.4 GPa to ∼4.8 GPa. This uncertainty is problematic for constructing large-scale numerical models of the early stages of India-Asia collision. To address this, we provide new constraints on the tectonothermal evolution of the massif via a combined geodynamic and petrological forward-modelling approach. A prograde-to-peak pressure-temperature-time (P-T-t) path has been derived from thermomechanical simulations tailored for Eocene subduction in the northwestern Himalaya. Phase equilibrium modelling performed along this P-T path has described the petrological evolution of felsic and mafic components of the massif crust, and shows that differences in their fluid contents would have controlled the degree of metamorphic phase transformation in each during subduction. Our model predicts that peak P-T conditions of ∼2.6-2.8 GPa and ∼600-620 ∘C, representative of 90-100 km depth (assuming lithostatic pressure), could have been reached just ∼3 Myr after the onset of subduction of continental crust. This P-T path and subduction duration correlate well with constraints reported for similar UHP eclogite in the Kaghan Valley, Pakistan Himalaya, suggesting that the northwest Himalaya contains dismembered remnants of what may have been a ∼400-km-long UHP terrane comparable in size to the Western Gneiss Region, Norway, and the Dabie-Sulu belt, China. A maximum overpressure of ∼0.5 GPa was calculated in our simulations for a homogeneous crust, although small-scale mechanical heterogeneities may produce overpressures that are larger in magnitude. Nonetheless, the extremely high pressures for peak metamorphism reported by some workers (up to 4.8 GPa) are unreliable owing to conventional thermobarometry

  3. Petrologic and chemical changes in ductile shear zones as a function of depth in the continental crust

    Science.gov (United States)

    Yang, Xin-Yue

    Petrologic and geochemical changes in ductile shear zones are important for understanding deformational and geochemical processes of the continental crust. This study examines three shear zones that formed under conditions varying from lower greenschist facies to upper amphibolite facies in order to document the petrologic and geochemical changes of deformed rocks at various metamorphic grades. The studied shear zones include two greenschist facies shear zones in the southern Appalachians and an upper amphibolite facies shear zone in southern Ontario. The mylonitic gneisses and mylonites in the Roses Mill shear zone of central Virginia are derived from a ferrodiorite protolith and characterized by a lower greenschist facies mineral assemblage. Both pressure solution and recrystallization were operative deformation mechanisms during mylonitization in this shear zone. Strain-driven dissolution and solution transfer played an important role in the mobilization of felsic components (Si, Al, K, Na, and Ca). During mylonitization, 17% to 32% bulk rock volume losses of mylonites are mainly attributed to removal of these mobile felsic components by a fluid phase. Mafic components (Fe, Mg, Ti, Mn and P) and trace elements, REE, Y, V and Sc, were immobile. At Rosman, North Carolina, the Brevard shear zone (BSZ) shows a deformational transition from the coarse-grained Henderson augen gneiss (HAG) to proto-mylonite, mylonite and ultra-mylonite. The mylonites contain a retrograde mineral assemblage as a product of fluid-assisted chemical breakdown of K-feldspar and biotite at higher greenschist facies conditions. Recrystallization and intra-crystalline plastic deformation are major deformation mechanisms in the BSZ. Fluid-assisted mylonitization in the BSZ led to 6% to 23% bulk volume losses in mylonites. During mylonitization, both major felsic and mafic elements and trace elements, Rb, Sr, Zr, V, Sc, and LREE were mobile; however, the HREEs were likely immobile. A shear zone

  4. 78 FR 77141 - U.S. Customs and Border Protection 2014 East Coast Trade Symposium: “Increasing Economic...

    Science.gov (United States)

    2013-12-20

    ..., 2013. Maria Luisa Boyce, Senior Advisor for Private Sector Engagement, Executive Director, Office of... Protection 2014 East Coast Trade Symposium: ``Increasing Economic Competitiveness Through Global Partnership... Competitiveness Through Global Partnership and Innovation.'' The format of the East Coast Trade Symposium will be...

  5. Controls of Ca/Mg/Fe activity ratios in pore water chemistry models of the Callovian-Oxfordian clay formation

    Energy Technology Data Exchange (ETDEWEB)

    Lerouge, C.; Grangeon, S.; Wille, G.; Flehoc, C.; Gailhanou, H.; Gaucher, E.C.; Tournassat, C. [BRGM av. Claude Guillemin BP6009 45060 Orleans cedex 2 (France); Vinsot, A. [ANDRA Meuse/Haute-Marne Underground research Laboratory (URL), RD 960, 55290 Bure (France); Made, B.; Altmann, S. [ANDRA - Parc de la Croix Blanche, 1-7 rue Jean Monnet, 92298 Chatenay-Malabry Cedex (France)

    2013-07-01

    In the pore water chemistry model of the Callovian-Oxfordian clay formation, the divalent cations Ca, Mg, and Fe are controlled by equilibrium reactions with pure carbonates: calcite for Ca, dolomite for Mg, and siderite for Fe. Results of a petrological study and computing of the Ca/Mg and Ca/Fe activity ratios based on natural pore water chemistry provide evidence that equilibrium with pure calcite and pure dolomite is a reasonable assumption for undisturbed pore waters; on the other hand, siderite cannot be considered at equilibrium with pore waters at the formation scale. (authors)

  6. Controls of Ca/Mg/Fe activity ratios in pore water chemistry models of the Callovian-Oxfordian clay formation

    International Nuclear Information System (INIS)

    Lerouge, C.; Grangeon, S.; Wille, G.; Flehoc, C.; Gailhanou, H.; Gaucher, E.C.; Tournassat, C.; Vinsot, A.; Made, B.; Altmann, S.

    2013-01-01

    In the pore water chemistry model of the Callovian-Oxfordian clay formation, the divalent cations Ca, Mg, and Fe are controlled by equilibrium reactions with pure carbonates: calcite for Ca, dolomite for Mg, and siderite for Fe. Results of a petrological study and computing of the Ca/Mg and Ca/Fe activity ratios based on natural pore water chemistry provide evidence that equilibrium with pure calcite and pure dolomite is a reasonable assumption for undisturbed pore waters; on the other hand, siderite cannot be considered at equilibrium with pore waters at the formation scale. (authors)

  7. Stellar formation

    CERN Document Server

    Reddish, V C

    1978-01-01

    Stellar Formation brings together knowledge about the formation of stars. In seeking to determine the conditions necessary for star formation, this book examines questions such as how, where, and why stars form, and at what rate and with what properties. This text also considers whether the formation of a star is an accident or an integral part of the physical properties of matter. This book consists of 13 chapters divided into two sections and begins with an overview of theories that explain star formation as well as the state of knowledge of star formation in comparison to stellar structure

  8. Supporting online materials for mineralogy and petrology of Comet81P/Wild 2 nucleus samples

    Energy Technology Data Exchange (ETDEWEB)

    Zolensky, Michael E.; Zega, Thomas J.; Yano, Hajime; Wirick, Sue; Westphal, Andrew J.; Weisberg, Mike K.; Weber, Iris; Warren, Jack L.; Velbel, Michael A.; Tsuchiyama, Akira; Tsou, Peter; Toppani, Alice; Tomioka, Naotaka; Tomeoka, Kazushige; Teslich, Nick; Taheri, Mitra; Susini, Jean; Stroud, Rhonda; Stephan, Thomas; Stadermann, Frank J.; Snead, Christopher J.; Simon, Steven B.; Simionovici, Alexandre; See,Thomas H.; Robert Francois; Rietmeijer, Frans J.M.; Rao, William; Perronnet, Murielle C.; Papanastassiou, Dimitri A.; Okudaira, Kyoko; Ohsumi, Kazumasa; Ohnishi, Ichiro; Nakamura-Messenger, Keilo; Nakamura,Tomoki; Mostefaoui, Smail; Mikouchi, Takashi; Meibom, Anders; Matrajt,Graciela; Marcus, Matthew A.; Leroux, Hugues; Lemelle, Laurence; Antonio,Loan Le; Lanzirotti, Antonio; Langenhorst, Falko; Krot, Alexander N.; Keller, Lindsay P.; Kearsley, Anton T.; Joswiak, Davis; Jacob, Damien; Ishii, Hope; Harvey, Ralph; Hagiya, Kenji; Grossman, Lawrence; Grossman,Jeffrey N.; Graham, Giles A.; Gounelle, Matthieu; Gillet, Philippe; Genge, Matthew J.; Flynn, George; Ferroir, Tristan; Fallow, Stewart; Ebel, Denton S.; Dai, Zu Rong; Cordier, Patrick; Clark, Benton; Chi,Miaofang; Butterworth, Anna L.; Brownlee, Donald E.; Bridges, John C.; Brennan, Sean; Brearley, Adrian; Bradley, John P.; Bleuet, Pierre; Bland,Phil A.; Bastien, Ron

    2006-01-01

    The bulk of the comet 81P/Wild 2 (hereafter Wild 2) samples returned to Earth by the Stardust spacecraft appear to be weakly constructed mixtures of nanometer-scale grains, with occasional much larger (over 1 micrometer) ferromagnesian silicates, Fe-Ni sulfides, Fe-Ni metal, and accessory phases. The very wide range of olivine and low-Ca pyroxene compositions in comet Wild 2 requires a wide range of formation conditions, probably reflecting very different formation locations in the protoplanetary disk. The restricted compositional ranges of Fe-Ni sulfides, the wide range for silicates, and the absence of hydrous phases indicate that comet Wild 2 experienced little or no aqueous alteration. Less abundant Wild 2 materials include a refractory particle, whose presence appears to require radial transport in the early protoplanetary disk.

  9. Radioactive elements behaviour in multiphase intrusive series and petrological significance of radiogeochemical data

    International Nuclear Information System (INIS)

    Ponomareva, A.P.; Zlobin, V.A.

    1982-01-01

    The behaviour of radioactive elements (RE) during formation of multiphase intrusive series of various ages, types and alkalinity nature, placed in different structural formation zones of West Uzbekistan is discussed (on the basis of 230 quantitative determinations). It is established that maximum RE concentrations in the intrusive series considered are U=3-5, Th=11-17 g/t and correspond to granodiorites, adamellites, granites and granosienites. The typical behaviour for U and Th is the growth of their concentrations in the direction from gabbro- to granodiorites (granosienites) and granites, and then decrease to leucocrat granites (alkaline, biotite or bimica ones). The evolution of magmatic systems occurred not along the line of differentiation of melts, but along the line of their ''washing'' with fluid mainly at the level of magma generation and on their way to upper horizons of Earth crust. High concentrations (several times more than a clark) must occur in cases of additional RE introduction

  10. Nature and evolution of the meteorite parent bodies: Evidence from petrology and metallurgy

    Science.gov (United States)

    Wood, J. A.

    1978-01-01

    The physical as well as chemical properties of the meteorite parent bodies are reviewed and it is concluded that many differentiated meteorites were likely formed in asteroidal-sized parents. A new model is developed for the formation of pallasites at the interface between an iron core and olivine mantle in differentiated bodies only about 10 km in diameter, which are later incorporated into a second generation of larger (100 km) parent bodies.

  11. Petrology, geochronology, geochemistry and petrogenesis of Bajestan granitoids, North of Ferdows, Khorasan Razvi Province

    Directory of Open Access Journals (Sweden)

    Reyhaneh Ahmadirouhani

    2017-02-01

    Full Text Available Introduction The investigated area is situated in the south west of the Khorasan Razavi Province along the North West of the Lut Block. Different types of metal ore bodies along with non-metal deposits have already been documented in the Lut Block (Karimpour et al., 2008. Most of the study area is covered with granitoid rocks. Metamorphic rocks with unknown age are present in the north of the area. Skarns are observed in contact with fault zones and intrusive bodies. Eocene volcanic rocks with andesite and andesibasalt composition are located in the east and north east of the area (Ahmadirouhani et al., 2015. The study area that is a part of the Lut Block has a high potentials for Cu, Fe, Au, and Barite mineralization along the observed alteration zones. In the present study, the petrography, petrogenesis, Sr–Nd isotopes, and U–Pb zircon age of acidic granitoids in the east of Bajestan were investigated. Materials and methods In the current study, 400 rock samples were collected from the field and 170 thin sections were prepared for petrography studies. Thirty samples of volcanic rocks, intrusions, and dykes were analyzed using XRF at the Geological Survey of Iran. Twenty-five samples were selected for the elemental analysis using ICP-MS by the Acme Lab Company (Canada, 16 samples of them were related to acidic intrusive bodies and dykes. In addition, zircon crystals from four samples of the granitoids bodies were collected for U–Pb dating. Approximately 50 zircon grains (i.e. euhedral, clear, uncracked crystals with no visible heritage cores and no inclusions were hand-picked from each sample. Through cathodoluminescence imaging, the internal structure and the origin of zircon grains were examined at the Geological Survey of Vienna, Austria. Moreover, zircons were dated using the (LA-ICP-MS method at the Laboratory of Geochronology, the University of Vienna, Austria using the methodology outlined in Klötzli et al., (2009. Sr and Nd

  12. Galaxy formation

    International Nuclear Information System (INIS)

    Silk, J.; Di Cintio, A.; Dvorkin, I.

    2014-01-01

    Galaxy formation is at the forefront of observation and theory in cosmology. An improved understanding is essential for improving our knowledge both of the cosmological parameters, of the contents of the universe, and of our origins. In these lectures intended for graduate students, galaxy formation theory is reviewed and confronted with recent observational issues. In lecture 1, the following topics are presented: star formation considerations, including IMF, star formation efficiency and star formation rate, the origin of the galaxy luminosity function, and feedback in dwarf galaxies. In lecture 2, we describe formation of disks and massive spheroids, including the growth of supermassive black holes, negative feedback in spheroids, the AGN-star formation connection, star formation rates at high redshift and the baryon fraction in galaxies.

  13. Petrological features of selected components of the Cergowa sandstones (Outer Carpathians) recorded by scanning electron microscopy - preliminary study

    Science.gov (United States)

    Pszonka, Joanna

    2017-11-01

    The scanning electron microscope analysis of the Cergowa sandstones brings new data on their petrological features and chemical composition. Previous work in standard petrographic examination, e.g. polarising (PL) or cathodoluminescence (CL) microscopy, displayed limited information on grain surface topography and only assumptions to their geochemistry. Both identification and characterisation of minerals are fundamental in the progress of mining and minerals processing systems. Detrital grains of the Cergowa sandstones are bound by calcite and dolomitic cement and commonly corroded by diagenetic fluids, however, in varying degrees, which is illustrated here by feldspar, quartz and dolomite minerals. Dissolution processes of marginal parts of these mineral grains resulted in corrosion, which increased the contact surface between the grains and the cement. The difference in resistance to these processes was observed not only among distinct groups of minerals, but also within the group of feldspars: between K-feldspars and minerals of plagioclase. That combination resulted in exceptionally strong cementation of the Cergowa sandstones, which is expressed by their high hardness and resistance to abrasion, freezing, and thawing. Inherent parameters of sandstones are characterised by their petrographical properties.

  14. Petrological features of selected components of the Cergowa sandstones (Outer Carpathians recorded by scanning electron microscopy – preliminary study

    Directory of Open Access Journals (Sweden)

    Pszonka Joanna

    2017-01-01

    Full Text Available The scanning electron microscope analysis of the Cergowa sandstones brings new data on their petrological features and chemical composition. Previous work in standard petrographic examination, e.g. polarising (PL or cathodoluminescence (CL microscopy, displayed limited information on grain surface topography and only assumptions to their geochemistry. Both identification and characterisation of minerals are fundamental in the progress of mining and minerals processing systems. Detrital grains of the Cergowa sandstones are bound by calcite and dolomitic cement and commonly corroded by diagenetic fluids, however, in varying degrees, which is illustrated here by feldspar, quartz and dolomite minerals. Dissolution processes of marginal parts of these mineral grains resulted in corrosion, which increased the contact surface between the grains and the cement. The difference in resistance to these processes was observed not only among distinct groups of minerals, but also within the group of feldspars: between K–feldspars and minerals of plagioclase. That combination resulted in exceptionally strong cementation of the Cergowa sandstones, which is expressed by their high hardness and resistance to abrasion, freezing, and thawing. Inherent parameters of sandstones are characterised by their petrographical properties.

  15. Organic petrology and geochemistry of the Carboniferous coal seams from the Central Asturian Coal Basin (NW Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Piedad-Sanchez, Noe; Martinez, Luis; Izart, Alain; Elie, Marcel [UMR G2R/7566, Geologie et Gestion des Ressources Minerales et Energetiques, Faculte des Sciences, Universite Henri Poincare, Nancy 1, BP-239, Boulevard des Aiguillettes, Vandoeuvre-les-Nancy Cedex 54506 (France); Suarez-Ruiz, Isabel [Instituto Nacional del Carbon (CSIC), C/ Francisco Pintado Fe, 26, Ap. Co., 73, Oviedo 33011 (Spain); Keravis, Didier [Institut des Sciences de la Terre (ISTO), CNRS-Universite d' Orleans, Batiment Geosciences, BP 6759, Orleans 45067 (France)

    2004-03-23

    This paper presents for the first time a petrological and geochemical study of coals from the Central Asturian Coal Basin (North Spain) of Carboniferous (Pennsylvanian), mainly of Moscovian, age. A paleoenvironmental approach was used, taking into account both petrographic and organic geochemical studies. Vitrinite reflectance (R{sub r}) ranges from 0.5% to 2.5%, which indicates a high volatile bituminous to semianthracite and anthracite coal rank. The coal samples selected for paleoenvironmental reconstruction are located inside the oil-gas-prone phase, corresponding to the interval between the onset of oil generation and first gas generation and efficient expulsion of oil. This phase is represented by coals that have retained their hydrocarbon potential and also preserved biomarker information. Paleodepositional reconstruction based on maceral and petrographic indices points to a swamp environment with vitrinite-rich coal facies and variable mineral matter content. The gelification index (GI) and groundwater influence index (GWI) indicate strong gelification and wet conditions. The biomarkers exhibit a high pristane/phytane ratio, suggesting an increase in this ratio from diagenetic processes, and a high diterpanes ratio. This, in turn, would seem to indicate a high swamp water table and a humid climate. The maximum point of coal accumulation occurred during the regressive part of the Late Moscovian sequence and in the most humid climate described for this period of time in the well-known coal basins of Europe and North America.

  16. NO to ¥E$? Enhancing Economic Integration in East Asia through Closer Monetary Cooperation

    OpenAIRE

    Lamberte, Mario B.; Milo, Melanie S.; Pontines, Victor

    2001-01-01

    This paper has reviewed four major developments in the last 30 years: the collapse of the Bretton Woods arrangements; deepening of economic integration worldwide; the frequency and severity of the crises that affected not only developing economies but developed economies as well; and the formation of the Euroland. Against this background was the increasing intra-regional trade and investment in East Asia. Existing empirical studies generally show that East Asia has satisfied the economic crit...

  17. Geology, petrology, and petrogenesis of Little Barrier Island, Hauraki Gulf, New Zealand

    International Nuclear Information System (INIS)

    Lindsay, J.M.; Worthington, T.J.; Smith, I.E.M.; Black, P.M.

    1999-01-01

    Little Barrier Island is the emergent part of a large, isolated, dacite-rhyodacite volcano in the active Hauraki Rift, 80 km northeast of Auckland. Two volcanic episodes are recognised: Waimaomao Formation was emplaced as a rhyodacite dome at 3 Ma, whereas the more extensive dacitic lavas of Haowhenua Formation were erupted between 1.2 and 1.6 Ma. All Little Barrier lavas are strongly porphyritic and contain phenocrysts of plagioclase, orthopyroxene, and hornblende. Geochemically, they are subduction related and distinct from the older lavas of the Coromandel Volcanic Group, being Zr rich but Rb and Ba poor. Their Sr and Nd isotope ratios are similar to those of the Tonga-Kermadec arc volcanoes. Modelling of the dacite supports petrographic evidence that recharge and mixing were important in the magmatic system. Little Barrier and two dacite domes of similar age and composition near Whangarei form a northwest-trending lineament subparallel to the Alexandra Volcanics and the Vening Meinesz Fracture Zone. (author). 49 refs., 13 figs., 5 tabs

  18. Organic petrology, mineralogy and depositional environment of the Kipra lignite seam, Maritza-West basin, Bulgaria

    Energy Technology Data Exchange (ETDEWEB)

    Kostova, Irena [Department of Geology and Palaeontology, Sofia University ' ' St. Kliment Ohridski' ' , 1000, Sofia (Bulgaria); Zdravkov, Alexander [Department of Economic Geology, University of Mining and Geology ' ' St. Ivan Rilski' ' , 1700, Sofia (Bulgaria)

    2007-08-01

    The aim of the present study is to provide additional information about the properties and depositional environment of the Kipra lignite seam, which was deposited during the regressive stage of development of the Maritza-West basin. Petrographical and mineralogical data, along with ash yields and sulphur contents of 24 samples from a seam profile, have been used to study the vertical variation of the depositional settings during peat accumulation and subsequent coalification. The Kipra lignite is characterized by high ash yields and sulphur contents. It formed in a rheotrophic, low-lying mire with alkaline pH value. Vegetation with low preservation potential dominated within the palaeomire. During peat formation, frequent changes of the water level controlled the depositional environment. During the deposition of units 1 and 2, high water energy caused the transportation of high amounts of inorganic material into the mire, resulting in the formation of weakly gelified mineral-rich lignite. The organic matter from units 3 and 4 is characterized by enhanced gelification, which probably reflects the decreasing energy of the system. Good positive correlation between sulphur contents and the GI values was established in units 4, indicating that the gelification of the tissues was probably mainly controlled by the bacterial activity. In contrast, the gelification of the samples from unit 3 of the Kipra seam was probably governed by the redox conditions. The organic matter deposited under relatively wet conditions, in which the thermal and oxidative destruction of the tissues, was limited. A variety of major, minor and accessory minerals are present in Maritza-West lignite. The mineral composition is dominated mainly by pyrite, gypsum and calcite, and to a lesser extent limonite, quartz, kaolinite, montmorillonite, illite, chlorite and plagioclase. Jarosite, hematite, halloysite, mica, K-feldspar, aragonite, siderite, and dolomite were also determined in very low

  19. Petrology and geochronology of the Cacapava do Sul batholith, state of Rio Grande do Sul, Brazil

    International Nuclear Information System (INIS)

    Sartori, P.L.P.; Kawashita, K.

    1985-01-01

    The batholith of Cacapava do Sul, Brazil, is composed of granitic rocks represented by leucogranites, syenogranites, monzogranites and granodiorites, arranged in a complex way. These rocks represent a calcalkaline suite of compressional tectonic setting. The general characteristics described with respect to it's petrography, chemical composition and geological setting show similarities with mesozone plutons. The pluton intruded the metamorphic rocks of the Vacacai Formation and the type of emplacement mechanism was forceful. According to the Rb-Sr total rock isochron age determinations, its consolidation took place throughout the Cambrian period. This result agrees with previous K-Ar age determinations. The intrusion occurred at the end of the Brasiliano orogenic cycle, when the metamorphic and folding phenomena had already ceased and the morphogenesis was in progress, since the temperature for radiometric argon retention was reached rapidly. (D.J.M.) [pt

  20. Petrology of dune sand derived from basalt on the Ka'u Desert, Hawaii

    Science.gov (United States)

    Gooding, J. L.

    1982-01-01

    Dune sand from the Ka'u Desert, southwest flank of Kilauea volcano, Hawaii, is moderately well-sorted (median = 1.60 Phi, deviation = 0.60, skewness = 0.25, kurtosis = 0.68) and composed mostly of frosted subangular particles of basalt glass ('unfractionated' olivine-normative tholeitte), olivine, lithic fragments (subophitic and intersertal basalts; magnetite-ilmenite-rich basalts), reticular basalt glass, magnetite, ilmenite, and plagioclase, in approximately that order of abundance. Quantitative lithological comparison of the dune sand with sand-sized ash from the Keanakakoi Formation supports suggestions that the dune sand was derived largely from Keanakakoi ash. The dune sand is too well sorted to have been emplaced in its present form by base-surge but could have evolved by post-eruption reworking of the ash.

  1. Geology, petrology and geochronology of meridional and oriental regions of the Morungaba complex, SP

    International Nuclear Information System (INIS)

    Vlach, S.R.F.

    1985-01-01

    This work studies the Morungaba Intensive Complex, in Southwestern of Sao Paulo State. Formed principally by granitoid rocks with biotite. 31 granitoid facies with structural was recognized. Petrographic own characteristics. The rocks from Morungaba Complex was joint in three magmatics groups, denominated: Roby Gray and Porphyritic. Petrographic and mineralogical composition studies of this three groups were done. Geochranological studies by Rb/Sr and K/sr methods made possible to establish the ages and evolution of this rocks. This Complex formation and evolution are associated with the dioritic rocks presence. This work also concluded that the Morungaba Intrusive Complex represent the pos-orogenic wents from Brazilian Cycle. (C.D.G.) [pt

  2. Coordinated Oxygen Isotopic and Petrologic Studies of CAIS Record Varying Composition of Protosolar

    Science.gov (United States)

    Simon, Justin I.; Matzel, J. E. P.; Simon, S. B.; Weber, P. K.; Grossman, L.; Ross, D. K.; Hutcheon, I. D.

    2012-01-01

    Ca-, Al-rich inclusions (CAIs) record the O-isotope composition of Solar nebular gas from which they grew [1]. High spatial resolution O-isotope measurements afforded by ion microprobe analysis across the rims and margin of CAIs reveal systematic variations in (Delta)O-17 and suggest formation from a diversity of nebular environments [2-4]. This heterogeneity has been explained by isotopic mixing between the O-16-rich Solar reservoir [6] and a second O-16-poor reservoir (probably nebular gas) with a "planetary-like" isotopic composition [e.g., 1, 6-7], but the mechanism and location(s) where these events occur within the protoplanetary disk remain uncertain. The orientation of large and systematic variations in (Delta)O-17 reported by [3] for a compact Type A CAI from the Efremovka reduced CV3 chondrite differs dramatically from reports by [4] of a similar CAI, A37 from the Allende oxidized CV3 chondrite. Both studies conclude that CAIs were exposed to distinct, nebular O-isotope reservoirs, implying the transfer of CAIs among different settings within the protoplanetary disk [4]. To test this hypothesis further and the extent of intra-CAI O-isotopic variation, a pristine compact Type A CAI, Ef-1 from Efremovka, and a Type B2 CAI, TS4 from Allende were studied. Our new results are equally intriguing because, collectively, O-isotopic zoning patterns in the CAIs indicate a progressive and cyclic record. The results imply that CAIs were commonly exposed to multiple environments of distinct gas during their formation. Numerical models help constrain conditions and duration of these events.

  3. Geology of the Baskil (Elazığ Area and the Petrology of Baskil Magmatics

    Directory of Open Access Journals (Sweden)

    H. Jerf ASUTAY

    1986-06-01

    Full Text Available The study area which covers the region around Baskil on Eastern Taurus Range comprises of Keban metamorphics and Baskil magmatics overlain by a Tertiary sedimentary cover. The Keban metamorphics are represented by regional and contact metamorphic rocks in the study area. Calc schist and marble associations are widespread on the regional scale. Between Baskil granite and Keban metamorphics exomorphism and endomorphism zones have been developed. Metasomatic effects are observed in the contact metamorphic rocks which reflect the pyroxene-hornfels facies. The sedimentary sequence begins with Middle Paleocene (Thanetian aged rocks in the study area. The same sequence, however, has been deposited starting in Santonian-Campanian in the surrounding area. The sedimentary rock sequence which is composed of Kuşçular conglomerate, Seske formation, Kırkgeçit formation (Paleocene-Plio-Quaternary are represented by conglomerate, carbonates and flysch kind of sedimentary rocks. Baskil magmatics are an association of plutonic, hypabyssal and volcanic rocks. Of this association, Baskil granite contains dioritic, monzonitic and tonalitic kind of magmatic rocks which are mostly observed as transitional. Baskil granite, in the study area, is frequently cut across by basic and acidic dykes which locally intrudes between the granite and the basaltic, andesitic rocks overlying the granite and are transitional with the volcanics. Chemically, Baskil granite is of calc-alkaline type. It is rich in silica and alkaline. Trace element distribution is quite regular. Baskil granite which is determined as of type 'I' is generally rich in hornblende but poor in muscovite and biotite. It shows the features of continental margin magmatism and is an example of systematic differentiation. Considering their features and under the light of plate tectonics concept, Baskil magmatics may be said to be a product of continental margin magmatism. They are, presumably, the products of an

  4. Forests of East Texas, 2014

    Science.gov (United States)

    Thomas J. Brandeis

    2015-01-01

    This resource update provides an overview of forest resources in east Texas derived from an inventory conducted by the U.S. Forest Service, Forest Inventory and Analysis (FIA) Program at the Southern Research Station in cooperation with the Texas A&M Forest Service. These estimates are based on field data collected using the FIA annualized sample design and are...

  5. Forests of east Texas, 2013

    Science.gov (United States)

    K.J.W. Dooley; T.J. Brandeis

    2014-01-01

    This resource update provides an overview of forest resources in east Texas based on an inventory conducted by the U.S. Forest Service, Forest Inventory and Analysis (FIA) program at the Southern Research Station in cooperation with the Texas A&M Forest Service. Forest resource estimates are based on field data collected using the FIA annualized sample design and...

  6. Forests of east Texas, 2016

    Science.gov (United States)

    Kerry Dooley

    2018-01-01

    This resource update provides an overview of forest resources in east Texas based on an inventory conducted by the U.S. Forest Service, Forest Inventory and Analysis (FIA) program at the Southern Research Station (SRS) in cooperation with Texas A&M Forest Service. The 254 counties of Texas are consolidated into seven FIA survey units—Southeast (unit 1),...

  7. East African Journal of Statistics: Journal Sponsorship

    African Journals Online (AJOL)

    East African Journal of Statistics: Journal Sponsorship. Journal Home > About the Journal > East African Journal of Statistics: Journal Sponsorship. Log in or Register to get access to full text downloads.

  8. Multinationals and East Asian Integration | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... and the United States, in the recent and rapid economic growth and integration in East Asia. ... "dragons" of East Asia have emerged among the world's leading economic powers. ... Asian outlook: New growth dependent on new productivity.

  9. Highly refractory Archaean peridotite cumulates: Petrology and geochemistry of the Seqi Ultramafic Complex, SW Greenland

    Directory of Open Access Journals (Sweden)

    Kristoffer Szilas

    2018-05-01

    Full Text Available This paper investigates the petrogenesis of the Seqi Ultramafic Complex, which covers a total area of approximately 0.5 km2. The ultramafic rocks are hosted by tonalitic orthogneiss of the ca. 3000 Ma Akia terrane with crosscutting granitoid sheets providing an absolute minimum age of 2978 ± 8 Ma for the Seqi Ultramafic Complex. The Seqi rocks represent a broad range of olivine-dominated plutonic rocks with varying modal amounts of chromite, orthopyroxene and amphibole, i.e. various types of dunite (s.s., peridotite (s.l., as well as chromitite. The Seqi Ultramafic Complex is characterised primarily by refractory dunite, with highly forsteritic olivine with core compositions having Mg# ranging from about 91 to 93. The overall high modal contents, as well as the specific compositions, of chromite rule out that these rocks represent a fragment of Earth's mantle. The occurrence of stratiform chromitite bands in peridotite, thin chromite layers in dunite and poikilitic orthopyroxene in peridotite instead supports the interpretation that the Seqi Ultramafic Complex represents the remnant of a fragmented layered complex or a magma conduit, which was subsequently broken up and entrained during the formation of the regional continental crust.Integrating all of the characteristics of the Seqi Ultramafic Complex points to formation of these highly refractory peridotites from an extremely magnesian (Mg# ∼ 80, near-anhydrous magma, as olivine-dominated cumulates with high modal contents of chromite. It is noted that the Seqi cumulates were derived from a mantle source by extreme degrees of partial melting (>40%. This mantle source could potentially represent the precursor for the sub-continental lithospheric mantle (SCLM in this region, which has previously been shown to be ultra-depleted. The Seqi Ultramafic Complex, as well as similar peridotite bodies in the Fiskefjord region, may thus constitute the earliest cumulates that formed during the

  10. Petrology and oxygen isotope geochemistry of the Pucon ignimbrite - Southern Andean volcanic zone, Chile: Implications for genesis of mafic ignimbrites

    International Nuclear Information System (INIS)

    McCurry, Michael; Schmidt, Keegan

    2001-01-01

    Although mafic components of dominantly intermediate to silicic ignimbrites are rather common, voluminous, dominantly mafic ignimbrites are rare (e.g., Smith, 1979; cf. Freundt and Schmincke, 1995). Volcan Villarrica, the most active composite volcano in South America, located in the Southern Andean Volcanic Zone (SAVZ, Lopez-Escobar and Moreno, 1994a), has produced two such ignimbrites, respectively the Lican and Pucon Ignimbrites, in the last 14,000 years (Clavero, 1996). The two ignimbrites are low-Si andesite and basaltic-andesite to low-Si andesite, respectively, the former about twice as voluminous as the later (10 and 5 km 3 ). Eruption of the ignimbrites produced calderas respectively 5 and 2 km in diameter (Moreno, 1995; Clavero, 1996). In addition to its mafic bulk composition, the Pucon Ignimbrite (PI) is also distinguished by numerous xenolithic fragments among and also within magmatic pyroclasts. Many of these are fragments of granitoid rocks. Volcan Villarrica has also produced numerous smaller mafic ignimbrites and pyroclastic surge deposits, as well as dominantly basaltic fallout and lava flows (Lopez-Escobar and Moreno, 1994; Moreno, 1995; Clavero, 1996; Hickey-Vargas et al., 1989; Tormey et al., 1991). Reasons for the unusual style of mafic explosive activity at Volcan Villarrica are unclear. Clavero (1996), based upon an exemplary thesis-study of the physical volcanology and petrology of the PI, suggests it formed in response to a sequence of events beginning with injection of a shallow basaltic andesite magma chamber by hotter basaltic magma. In his model mixing and heat transfer between the two magmas initiated a violent Strombolian eruption that destabilized the chamber causing infiltration of large amounts of meteoric-water saturated country rocks. The Pucon Ignimbrite formed in response to subsequent phreatomagmatic interactions. In contrast, Lopez-Escobar and Moreno (1994) infer on geochemical grounds that volatiles leading to the explosive

  11. A field trip guide to the petrology of Quaternary volcanism on the Yellowstone Plateau

    Science.gov (United States)

    Vazquez, Jorge A.; Stelten, Mark; Bindeman, Ilya N.; Cooper, Kari

    2017-12-19

    The Yellowstone Plateau is one of the largest manifestations of silicic volcanism on Earth, and marks the youngest focus of magmatism associated with the Yellowstone Hot Spot. The earliest products of Yellowstone Hot Spot volcanism are from ~17 million years ago, but may be as old as ~32 Ma, and include contemporaneous eruption of voluminous mafic and silicic magmas, which are mostly located in the region of northwestern Nevada and southeastern Oregon. Since 17 Ma, the main locus of Yellowstone Hot Spot volcanism has migrated northeastward producing numerous silicic caldera complexes that generally remain active for ~2–4 million years, with the present-day focus being the Yellowstone Plateau. Northeastward migration of volcanism associated with the Yellowstone Hot Spot resulted in the formation of the Snake River Plain, a low relief physiographic feature extending ~750 kilometers from northern Nevada to eastern Idaho. Most of the silicic volcanic centers along the Snake River Plain have been inundated by younger basalt volcanism, but many of their ignimbrites and lava flows are exposed in the extended regions at the margins of the Snake River Plain. 

  12. Petrographical, geochemical and petrological study of the xenoliths associating the basalt of (Southwest, Syria)

    International Nuclear Information System (INIS)

    Safarjalani, A.; Nasir, S.

    1998-01-01

    Alkali basalt spread northeast part of Shamah volcanic field (Southwest of Syria) belonging to the Neogene and Quaternary ages, which are coexisted with a great quantity of mafic and ultramafic xenoliths and megacrysts. Field observations and data of geochemical and petrographical studies results, for xenoliths coexisted with alkali basalt speared over the northwest part of the arabian plate (Syria) indicate availability of a proper environment where various kinds of xenoliths of lower crustal and upper mantle were formed, this indicates that these xenoliths have been formed under different thermo barometric conditions. The study of available mineral para genesis and geothermobarometrics on coexisting minerals suggests equilibration conditions, ranging between 6-8 kba for pressure and 850-920 Centigrade for temperature, and that is for xenoliths of gabbroic nature formed in the lower crustal between 20-27 km depth. With regard to the formation conditions of the xenoliths formed in the upper mantle (Pyroxenite and Lherzolite); they rang between 13.5 - 14.5 kba for pressure and 950-1060 Centigrade for temperature. (Author)

  13. Petrology of chromite in ureilites: Deconvolution of primary oxidation states and secondary reduction processes

    Science.gov (United States)

    Goodrich, Cyrena Anne; Harlow, George E.; Van Orman, James A.; Sutton, Stephen R.; Jercinovic, Michael J.; Mikouchi, Takashi

    2014-06-01

    Ureilites are ultramafic achondrites thought to be residues of partial melting on a carbon-rich asteroid. They show a trend of FeO-variation (olivine Fo from ∼74 to 95) that suggests variation in oxidation state. Whether this variation was established during high-temperature igneous processing on the ureilite parent body (UPB), or preserved from nebular precursors, is a subject of debate. The behavior of chromium in ureilites offers a way to assess redox conditions during their formation and address this issue, independent of Fo. We conducted a petrographic and mineral compositional study of occurrences of chromite (Cr-rich spinel) in ureilites, aimed at determining the origin of the chromite in each occurrence and using primary occurrences to constrain models of ureilite petrogenesis. Chromite was studied in LEW 88774 (Fo 74.2), NWA 766 (Fo 76.7), NWA 3109 (Fo 76.3), HaH 064 (Fo 77.5), LAP 03587 (Fo 74.9), CMS 04048 (Fo 76.4), LAP 02382 (Fo 78.6) and EET 96328 (Fo 85.2). Chromite occurs in LEW 88774 (∼5 vol.%), NWA 766 (event involved initial elevation of T (to 1300-1400 °C), followed by rapid decompression and drop in T (to exclusively in low-Fo samples supports the interpretation that the ureilite FeO-variation was established during igneous processing on the UPB.

  14. Preliminary results on the petrology and fluid inclusions of the Rossing uraniferous alaskites

    International Nuclear Information System (INIS)

    Cuney, M.

    1980-01-01

    Petrography, radioactivity distribution and fluid inclusions have been studied in three samples of the Rossing alaskites from the S.H. anomaly outside of the Rossing deposit. After the crystallization of the alaskitic magma which involved oligoclase, biotite, orthoclase and quartz, a deuteric alteration produced a quartz, microcline, albite, muscovite, calcite plus minus chlorite mineral association similar to those observed in several French uraniferous granites. Uranium redistribution occurred during this alteration. From fluid inclusions data, the pressure at the time of the intrusion is estimated to have been at least 6kbar for a temperature of 625 degrees Celsius. Reaction of the magma with the marbles of the Rossing formation led to the boiling of the magma by an increase in the CO 2 partial pressure as well as to its crystallization. Immiscibility between a dense saline (more than 30 per cent NaCl) and CO 2 -rich fluid is proposed to have occurred simultaneously or after the fluid oversaturation of the magma. Part of uraninite is formed at the magmatic stage, another part crystallized from the magmatic fluids in the biotite-rich selvages of the alaskites or in the uraninite-fluorite veins. Uraninite crystallization appears to be mainly controlled by the oxygen fugacity prevailing in the magma and in the surrounding rocks

  15. Cryogenian alkaline magmatism in the Southern Granulite Terrane, India: Petrology, geochemistry, zircon U-Pb ages and Lu-Hf isotopes

    Science.gov (United States)

    Santosh, M.; Yang, Qiong-Yan; Ram Mohan, M.; Tsunogae, T.; Shaji, E.; Satyanarayanan, M.

    2014-11-01

    The Southern Granulite Terrane (SGT) in India preserves the records of the formation and recycling of continental crust from Mesoarchean through Paleoproterozoic to Neoproterozoic and Cambrian, involving multiple subduction-accretion-collision associated with major orogenic cycles. A chain of unmetamorphosed and undeformed alkaline magmatic intrusions occurs along the northern margin of the SGT aligned along paleo-suture zones. Here we investigate two representative plutons from this suite, the Angadimogar syenite (AM) and the Peralimala alkali granite (PM) through field, petrological, geochemical, zircon U-Pb and Lu-Hf studies. Magma mixing and mingling textures and mineral assemblages typical of alkaline rocks are displayed by these plutons. The whole-rock major and trace element data characterize their alkaline nature. In trace element discrimination diagrams, the AM rocks straddle between the VAG (volcanic-arc granites) and WPG (within plate granites) fields with most of the samples confined to the VAG field, whereas the PM rocks are essentially confined to the WPG field. The diversity in some of the geochemical features between the two plutons is interpreted to be the reflection of source heterogeneities. Most zircon grains from the AM and PM plutons display oscillatory zoning typical of magmatic crystallization although some grains, particularly those from the PM pluton, show core-rim structures with dark patchy zoned cores surrounded by irregular thin rims resulting from fluid alteration. The weighted mean 206Pb/238U ages of the magmatic zircons from three samples of the AM syenite are in the range of 781.8 ± 3.8 Ma to 798 ± 3.6 Ma and those from two samples of the PM alkali granite yield ages of 797.5 ± 3.7 Ma and 799 ± 6.2 Ma. A mafic magmatic enclave from the AM pluton shows weighted mean 206Pb/238U age of 795 ± 3.3 Ma. The AM and PM plutons also carry rare xeneocrystic zircons which define upper intercept concordia ages of 3293 ± 13 Ma and 2530

  16. Organic petrological and organic geochemical characterisation of the Tertiary coal-bearing sequence of Batu Arang, Selangor, Malaysia

    Science.gov (United States)

    Wan Hasiah, Abdullah; Abolins, Peter

    1998-08-01

    The Tertiary coal-bearing sequence at Batu Arang in Selangor, Peninsular Malaysia consists of a sandstone-coal-oil shale facies assemblage. A detailed organic petrological and organic geochemical study was carried out on several organic-rich sediments from this sequence. The oil shales are dominated by Botryococcus-derived telalginite and Pediastrum-derived lamalginite. The coals, hypautochthonous in origin, are mainly duroclarite-type, although other minor microlithotypes also occur. Alginite is not observed in the coals, but other liptinitic constituents are very common, particularly thin-walled cutinite and sporinite. The oil shales and the coals are thermally immature. This immaturity has a considerable influence on the biomarker distributions, particularly so on the triterpanes which are dominated by C 31αβ 22R and C 30ββ compounds. Interestingly, for Tertiary aged sediments of continental origin, the diagnostic biomarker compounds such as 18 α(H)-oleanane and bicadinanes, normally linked to the higher land plant group of angiosperms, are not observed in the samples analysed. Tricyclic terpanes occur only in very low relative abundance or are virtually absent. A clear distinction, however, in the biomarker distributions of the shales and the coals/carbargilite can be made based upon the distribution of C 27-C 29 regular steranes: the shales, with a source input being predominantly planktonic algae, are dominated by 5 α(H),14 α(H),17 α(H) 20R cholestane, while the coals/carbargilites, with a source input consisting mainly of higher plant material, are dominated by 5 α(H),14 α(H),17 α(H) 20R ethyl cholestane. The depositional environment of the Batu Arang coal-bearing sequence is interpreted as varying from an alluvial flood plain peat-swamp to fluvio-lacustrine depositional setting.

  17. Terrane-Scale Metastability in Subducted Himalayan Continental Crust as Revealed by Integrated Petrological and Geodynamic Modeling

    Science.gov (United States)

    Palin, R. M.; Reuber, G. S.; White, R. W.; Kaus, B. J. P.; Weller, O. M.

    2017-12-01

    The Tso Morari massif, northwest India, is one of only two regions in the Himalayan Range that exposes subduction-related ultrahigh-pressure (UHP) metamorphic rocks. The tectonic evolution of the massif is strongly debated, however, as reported pressure estimates for peak metamorphism range between 2.4 GPa and 4.8 GPa. Such ambiguity hinders effective lithospheric-scale modeling of the early stages of the orogen's evolution. We present the results of integrated petrological and geodynamic modeling (Palin et al., 2017, EPSL) that provide new quantitative constraints on the prograde-to-peak pressure-temperature-time (P-T-t) path, and predict the parageneses that felsic and mafic components of the massif crust should have formed under equilibrium conditions. Our model shows that peak P-T conditions of 2.6-2.8 GPa and 600-620 °C, representative of subduction to 90-100 km depth (assuming lithostatic pressure), were reached just 3 Myr after the onset of collision. These P-T-t constraints correlate well with those reported for similar UHP eclogite in the along-strike Kaghan Valley, Pakistan, suggesting that the northwest Himalaya contains dismembered remnants of a 400-km long UHP terrane comparable in size to the Western Gneiss Region, Norway, and the Dabie-Sulu belt, China. The extremely high pressures (up to 4.8 GPa) for peak metamorphism reported by some workers are likely to be unreliable due to thermobarometry having been performed on minerals that did not represent equilibrium assemblages. Furthermore, key high-P minerals predicted to form in subducted Tso Morari continental crust (e.g. jadeite, Mg-rich garnet) are absent from natural samples in the region, reflecting the widespread metastable preservation of lower-pressure protolith assemblages during subduction and exhumation. This result questions the reliability of geodynamic simulations of orogenesis that are commonly predicated on equilibrium metamorphism operating continuously throughout tectonic cycles.

  18. Organic petrology and geochemistry of Eocene Suzak bituminous marl, north-central Afghanistan: Depositional environment and source rock potential

    Science.gov (United States)

    Hackley, Paul C.; Sanfilipo, John

    2016-01-01

    Organic geochemistry and petrology of Eocene Suzak bituminous marl outcrop samples from Madr village in north-central Afghanistan were characterized via an integrated analytical approach to evaluate depositional environment and source rock potential. Multiple proxies suggest the organic-rich (TOC ∼6 wt.%) bituminous marls are ‘immature’ for oil generation (e.g., vitrinite Ro  1) indicating organic input from marine algae and/or bacterial biomass, and sterane/hopane ratios are low (0.12–0.14). Monoaromatic steroids are dominated by C28clearly indicating a marine setting. High gammacerane index values (∼0.9) are consistent with anoxia stratification and may indicate intermittent saline-hypersaline conditions. Stable C isotope ratios also suggest a marine depositional scenario for the Suzak samples, consistent with the presence of marine foraminifera including abundant planktic globigerinida(?) and rare benthic discocyclina(?) and nummulites(?). Biomarker 2α-methylhopane for photosynthetic cyanobacteria implies shallow photic zone deposition of Madr marls and 3β-methylhopane indicates presence of methanotrophic archaea in the microbial consortium. The data presented herein are consistent with deposition of Suzak bituminous marls in shallow stratified waters of a restricted marine basin associated with the southeastern incipient or proto-Paratethys. Geochemical proxies from Suzak rock extracts (S content, high polar content, C isotopes, normal (αααR) C27–29 steranes, and C29/C30 and C26/C25 hopane ratios) are similar to extant data from Paleogene oils produced to the north in the Afghan-Tajik Basin. This observation may indicate laterally equivalent strata are effective source rocks as suggested by previous workers; however, further work is needed to strengthen oil-source correlations.

  19. Petrological study of the eastern part of Rio Maria batholith located in the SE of Para State

    International Nuclear Information System (INIS)

    Medeiros, H. de.

    1987-01-01

    This work is a petrological and geochronological study in the eastern part of Rio Maria batholith located in the SE of Para State (Brazil), in which granodioritic composition predominates. Selected samples including all varieties present in the eastern portion of Rio Maria granodioritic batholith were analyzed for major, minor and some trace elements. The results suggest two differentiation trends. The first is (BHGd + HBGd) - HBM sub(z)G, with decrease in CaO, TiO sub(2), Fe total, MgO and Sr contents, whereas K2O and Rb increase. The second trend is (BHGd + HBGd) - BGd, where the BGd have the highest values of SiO sub(2), and low CaO, TiO sub(2), Fe total, MgO and Sr contents. This results are in agreement with that obtained to the calc-alkaline rock series. Six selected samples, including all varieties, were dated by the Rb/Sr Whole-rock method, producing a isochronic age of 2564 +- 68 m.y. with an initial Sr sup(87)/Sr sup(86) ratio of 0.70288 +- 00092. The crystallization sequence proposed to the BHGd and BHGd, when correlated to the experimental results obtained in the rocks of granodioritic composition, suggests that the magma crystallization was in low pressure conditions (2 to 4kb). The temperature interval would be between 950 and +- 700 sup(0)C. The best explanation to the granodioritic magma origin is by partial fusion in the crustal base, with contribution of mantle material or not. The association of the rock units, including granodiorites, trondhjemites, meta-volcan-sedimentary sequences and gneisses of tonalitic to granodioritic composition observed in the Rio Maria region, and the Archaeyan ages obtained by the Rb/Sr method suggest that this region can be correlated with granite-greenstone terrains exposed in the Rhodesian, Kaapvaal and western Australia cratons. (author)

  20. A crustal-upper mantle model for southeastern Sicily (Italy) from the integration of petrologic and geophysical data

    Science.gov (United States)

    Manuella, Fabio Carmelo; Brancato, Alfonso; Carbone, Serafina; Gresta, Stefano

    2013-05-01

    An interdisciplinary approach is proposed to investigate the structure and composition of the Permo-Triassic basement of the Hyblean Plateau and Sicily Channel. Comparisons of published data on peridotites and spinels from different geodynamic settings, and new data on Hyblean spinels, reveal the affinity of the Hyblean basement with an ultra-slow spreading oceanic lithosphere, rather than with the Africa continental plate. Similar results derive from volcanic rocks of the studied area, whose Nb/Yb vs. Th/Yb ratio hints at their affinity with the MORB-OIB array, even excluding any possible contamination with continental crust lithologies, unlike North Africa lavas. The comparison of He isotopic ratios from Hyblean Plateau and Sicily Channel highlights their similarity with values measured in fluids emitted from the Rainbow and Logatchev hydrothermal fields in Mid-Atlantic Ridge. Based on petrologic and geochemical evidence for the oceanic nature of the Permo-Triassic basement in southeastern Sicily, and the occurrence of serpentinized harzburgite xenoliths in Hyblean diatremes, the P-wave velocity model proposed for the investigated area is used to estimate lithospheric pressure, density, degree of serpentinization and magnetic susceptibility also considering both abyssal and ophiolitic serpentinites. The resulting values suggest the presence of peridotites affected by different degrees of serpentinization (35-100 vol.%) ranging to a depth of 8-19 km. As a whole, combined seismic, gravimetric and magnetic data indicate the presence of a marked anomaly at a depth of about 19 km. As a consequence, we consider the Moho discontinuity as a serpentinization front, by fixing the relative top at a depth of 19 km. Our results suggest that the oceanic lithospheric model for southeastern Sicily could be broadened to the Sicily Channel, which is possibly correlated to the adjacent Ionian oceanic basin, inferred as belonging to the Oman-Iraq-Levantine-Sicily seaway.

  1. Middle East and North African Oil.

    Science.gov (United States)

    Al-Quazzaz, Ayad

    1981-01-01

    Traces the history of oil and natural gas in the Middle East and relates the importance of the Middle East's current stores of oil to economic development. Information is presented on the relationship of major oil companies and local governments, OPEC, rate of production, and the impact of oil on the societies of the Middle East and North Africa.…

  2. Scopus: Journal of East African Ornithology

    African Journals Online (AJOL)

    Scopus: Journal of East African Ornithology has been published since 1977 by the Bird Committee of the East Africa Natural History Society. Originally titled Scopus, the addition of Journal of East African Ornithology began with our January 2018 issue. The journal is published Open Access twice a year, typically in January ...

  3. Funding problems threaten Middle East's synchrotron

    CERN Multimedia

    McCabe, H

    1999-01-01

    Scientists will tour the Middle East to try to raise support for the Synchrotron radiation for Experimental Science and Applications in the Middle East project. The plan is to dismantle and move a decommissioned synchrotron from Berlin to the Middle East where scientists of any nationality would be able to use it (3 paragraphs).

  4. 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.

  5. Petrology and geochemistry of Late Holocene felsic magmas from Rungwe volcano (Tanzania), with implications for trachytic Rungwe Pumice eruption dynamics

    NARCIS (Netherlands)

    Fontijn, K.; Elburg, M.A.; Nikogosian, I.K.; van Bergen, M.J.; Ernst, G.G.J.

    2013-01-01

    Rungwe in southern Tanzania is an active volcanic centre in the East African Rift System, characterised by Plinian-style explosive eruptions of metaluminous to slightly peralkaline trachytic silica-undersaturated magmas during its late Holocene history. Variations in whole-rock major and trace

  6. Petrology of the gabbro and sheeted basaltic intrusives at North Cape, New Zealand

    International Nuclear Information System (INIS)

    Hopper, D.J.; Smith, I.E.M.

    1996-01-01

    The North Cape massif consists of a semi-conformable sequence of serpentinite, gabbro, sheeted sill and dike units, and pillow lavas. Although structurally disrupted, they can be interpreted in terms of an idealised ophiolite sequence and represent the most complete sequence in the Northland Ophiolite. Their age is considered to be Late Cretaceous-Paleocene on the basis of microfossils in associated sediments. Early Miocene K-Ar ages from igneous rocks are thought to reflect the time of emplacement as a thrust sheet of oceanic crust and upper mantle. The gabbros are divided into a lower unit characterised by well-developed cumulate layering and an upper unit which is massive; the sheeted sills and dikes are quartz-diorite and microgabbro interleaved with minor pillow lava. Two phases of alteration are observed, a pervasive low-grade greenschist metamorphism attributed to sea-water interaction after formation as oceanic crust, and an overprinting zeolitic alteration which is possibly post-emplacement. Their tholeiitic nature as well as overlapping geochemical compositions suggest that the gabbros and sheeted dikes and sills represent different components of a single magmatic system related by simple fractionation processes. Several lines of evidence suggest that the magmas that formed the North Cape gabbro and sheeted intrusives have subduction-related chemical characteristics. In the gabbro, calcic plagioclase (An 86-92 ) and depleted Zr and Y abundances, and in the sheeted intrusives depleted high field strength element abundances relative to typical MORB, is indicative of a subduction signature. The presence of subduction-related characteristics within the Northland Ophiolite suggests that it may have originated at a back-arc basin rather than a major ocean ridge spreading centre. (author). 64 refs., 12 figs., 7 tabs

  7. Portulacaria afra in East AFrica | Newton | Journal of East African ...

    African Journals Online (AJOL)

    No Abstract. East African Journal of Natural History Vol. 96 (1) 2007: pp. 107-108. http://dx.doi.org/10.2982/0012-8317(2007)96[107:PAIEA]2.0.CO;2 · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use ...

  8. Paleoproterozoic (ca. 1.8 Ga) arc magmatism in the Lützow-Holm Complex, East Antarctica: Implications for crustal growth and terrane assembly in erstwhile Gondwana fragments

    Science.gov (United States)

    Takahashi, Kazuki; Tsunogae, Toshiaki; Santosh, M.; Takamura, Yusuke; Tsutsumi, Yukiyasu

    2018-05-01

    The Lützow-Holm Complex (LHC) of East Antarctica forms a part of the latest Neoproterozoic-Cambrian high-grade metamorphic segment of the East African-Antarctic Orogen. Here we present new petrological, geochemical, and zircon U-Pb geochronological data on meta-igneous rocks from four localities (Austhovde, Telen, Skallevikshalsen, and Skallen) in the LHC, and evaluate the regional Paleoproterozoic (ca. 1.8 Ga) arc magmatism in this terrane for the first time. The geochemical features reveal a volcanic-arc affinity for most of the meta-igneous rocks from Austhovde and Telen, suggesting that the protoliths of these rocks were derived from felsic to mafic arc magmatic rocks. The protoliths of two mafic granulites from Austhovde are inferred as non-volcanic-arc basalt such as E-MORB, suggesting the accretion of remnant oceanic lithosphere together with the volcanic-arc components during the subduction-collision events. The weighted mean 206Pb/238U ages of the dominant population of magmatic zircons in felsic orthogneisses from Austhovde and Telen show 1819 ± 19 Ma and 1830 ± 10 Ma, respectively, corresponding to Paleoproterozoic magmatic event. The magmatic zircons in orthogneisses from other two localities yield upper intercept ages of 1837 ± 54 Ma (Skallevikshalsen), and 1856 ± 37 Ma and 1854 ± 45 Ma (Skallen), which also support Paleoproterozoic magmatism. The earlier thermal events during Neoarchean to Early Paleoproterozoic are also traced by 206Pb/238U ages of xenocrystic zircons in the felsic orthogneisses from Austhovde (2517 ± 17 Ma and 2495 ± 15 Ma) and Telen (2126 ± 16 Ma), suggesting partial reworking of the basement of a 2.5 Ga microcontinent during ca. 1.8 Ga continental-arc magmatism. The timing of peak metamorphism is inferred to be in the range of 645.6 ± 10.4 to 521.4 ± 12.0 Ma based on 206Pb/238U weighted mean ages of metamorphic zircon grains. The results of this study, together with the available magmatic ages as well as geophysical and

  9. Petrology and chemistry of the Green Acres gabbro complex near Winchester, Riverside County, California

    Science.gov (United States)

    Berger, Byron R.; Morton, Douglas M.; Miller, Fred K.

    2014-01-01

    emplacement played a role in layer formation in conjunction with thermal and hydraulic pressure perturbations.

  10. Petrography, mineral chemistry and geochemistry of post-ophiolitic volcanic rocks in the Ratouk area (south of Gazik, east of Iran

    Directory of Open Access Journals (Sweden)

    Zahra Vahedi Tabas

    2017-11-01

    Full Text Available Introduction Basaltic volcanoes are one of the volcanisms that have occurred in different parts of the world. The study of these lavas is important for petrologists, because they are seen in different tectonic settings and therefore diverse mechanisms affect their formation (Chen et al., 2007. Young volcanic rocks such as Quaternary basalts are one of latest products of magmatism in Iran that are related to deep fractures and active faults in Quaternary (Emami, 2000. The study area is located at 140km east of Birjand at Gazik 1:100000 geological map (Guillou et al., 1981 and have 60̊ 11' to 60̊ 15 '27" eastward longitude and 32̊ 33' 24" to 32̊ 39' 10" northward latitude. On the basis of structural subdivisions of Iran, this area is located in the northern part of the Sistan suture zone (Tirrul et al., 1983. Because of the importance of basaltic rocks in Sistan suture, this research is done with the aim of investigating the petrography and mineralogy of basaltic lavas, the nature of basaltic and intermediate magmatism and finally determination of tectonomagmatic regime. Materials and methods After field studies and sampling, 85 thin sections were prepared and carefully studied. Then ten samples with the lowest alteration were analyzed for major elements by inductively coupled plasma (ICP technologies and trace elements were analyzed using inductively coupled plasma mass spectrometry (ICP-MS, following a lithium metaborate/tetraborate fusion and nitric acid total digestion at the Acme laboratories, Vancouver, Canada. Electron probe micro analyses of clinopyroxene and olivine were done at the Iranian mineral processing research center (IMPRC by Cameca SX100 machine. X-ray diffraction analysis of minerals was done at the X-ray laboratory of the University of Birjand. Results In 60km south of GaziK at the east of the southern Khorasan province and the northern part of the Sistan suture zone, volcanic rocks with intermediate (Oligomiocene and

  11. Petrography and mineralgy of gachsaran formation in west of ...

    African Journals Online (AJOL)

    Gachsaran Formation is the most important cap rock of hydrocarbon reservoir in Iran and has important deposits of salt, sulfur and gypsum. A section of Gachsaran formation (Early to Middle Miocene) in south- east of zagros area, west of Bandar- e- Abbas province, was studied from sedimentary geology view. Gachsaran ...

  12. Energy supply in East Germany

    Energy Technology Data Exchange (ETDEWEB)

    Shimoyama, Tsutomu

    1988-07-10

    East Germany has abundant brown coal, about 90.4% of primary energy production in 1986. The high dependence upon brown coal has been established since its reevaluation in 1980 and the production is reaching a peak. Its share in power generation is also as high as 83.3% in the year. Therefore, the energy sufficiency of East Germany is about 80%. Problems are arising, however, in deterioration of excavation conditions and coal quality. Domestic energy resources such as the uranium and natural gas are also used to the maximum extent. The nuclear power has about 10% of share in the power generation. The share expansion policy is seemingly maintained even after the accident of Chernoble. Exploration, excavation and reprocessing of the uranium are conducted under the leadership of USSR. The country depends upon the oil in a very low level, less than 1%, as a result of the energy conservation policy in 1980's. (1 fig, 5 tabs)

  13. East African Cenozoic vegetation history.

    Science.gov (United States)

    Linder, Hans Peter

    2017-11-01

    The modern vegetation of East Africa is a complex mosaic of rainforest patches; small islands of tropic-alpine vegetation; extensive savannas, ranging from almost pure grassland to wooded savannas; thickets; and montane grassland and forest. Here I trace the evolution of these vegetation types through the Cenozoic. Paleogene East Africa was most likely geomorphologically subdued and, as the few Eocene fossil sites suggest, a woodland in a seasonal climate. Woodland rather than rainforest may well have been the regional vegetation. Mountain building started with the Oligocene trap lava flows in Ethiopia, on which rainforest developed, with little evidence of grass and none of montane forests. The uplift of the East African Plateau took place during the middle Miocene. Fossil sites indicate the presence of rainforest, montane forest and thicket, and wooded grassland, often in close juxtaposition, from 17 to 10 Ma. By 10 Ma, marine deposits indicate extensive grassland in the region and isotope analysis indicates that this was a C 3 grassland. In the later Miocene rifting, first of the western Albertine Rift and then of the eastern Gregory Rift, added to the complexity of the environment. The building of the high strato-volcanos during the later Mio-Pliocene added environments suitable for tropic-alpine vegetation. During this time, the C 3 grassland was replaced by C 4 savannas, although overall the extent of grassland was reduced from the mid-Miocene high to the current low level. Lake-level fluctuations during the Quaternary indicate substantial variation in rainfall, presumably as a result of movements in the intertropical convergence zone and the Congo air boundary, but the impact of these fluctuations on the vegetation is still speculative. I argue that, overall, there was an increase in the complexity of East African vegetation complexity during the Neogene, largely as a result of orogeny. The impact of Quaternary climatic fluctuation is still poorly understood

  14. East Asia basin Analysis Project

    International Nuclear Information System (INIS)

    Terman, M.J.

    1986-01-01

    The United Nations-related Committee for Coordination of Joint Prospecting for Mineral Resources in Asian Offshore Areas (CCOP), in cooperation with the International Union of Geological Sciences and Circum-Pacific Council, is implementing the East Asia Basin Analysis Project. National and regional organizations, principally members of the ASEAN Council of Petroleum, are compiling maps at a scale of 1:2 million and stratigraphic cross sections of basins, with particular initial emphasis on defining and assessing oil and gas plays and with later analytical focus on other sedimentary minerals (e.g., coal, phosphate, evaporites, and uranium). Completion is anticipated in 1988. Two major elements of the project are being contributed from other agencies. (1) Base maps. - The US Geological Survey (USGS) has partly compiled eight sheets covering east Asia that show bathymetry, shorelines, and drainage systems. One sheet also presents topography and selected cultural features. All sheets are scheduled to be completed in 1987. (2) Geotectonic maps. - The Working Group on Studies of East Asian Tectonics and Resources (SEATAR) is now completing 10 transect studies with crustal profiles and strip maps at a scale of 1:1 million. One map for each transect shows a plate tectonic interpretation. Transect coordinators or others will be encouraged to extrapolate between the strips and complete the geotectonic interpretation (on USGS bases) in 1987. The IGCP Project 220 is also compiling on (USGS bases) the tin and tungsten granites of east Asia, emphasizing geochemical data needed to identify predictive models. Other mapping will probably follow mineral-deposit modeling workshops on ophiolotic chromite and regional symposia on oceanic massive sulfide and subvolcanic gold and base metals. Completion may be possible by 1989

  15. Seroprevalence of Toxocariasis in Children in East- Azerbaijan Province, Iran

    Directory of Open Access Journals (Sweden)

    Yagoob Garedaghi

    2013-08-01

    Full Text Available Purpose: Toxocariasis is a zoonotic disease caused by the ascarid of dogs and cats, the main representative of which is a Toxocara canis. Distribution of the disease is world wide and is more prevalent in children. The present study was carried out in children of East Azerbaijan Province, Iran, to determine the toxocariasis seropositivity. Material and Methods: For the present seroepidemiological study, blood samples were collected at random from children of all the five districts of the East Azerbaijan Province. A total of 336 children, 187 males and 149 females in age group of 0-15 years were selected for the present study. ELISA was used for detection of IgG antibodies against Toxocara excretory secretary antigen. A questionnaire interview was conducted to obtain the data concerning their age, sex and habits. The particular points in the questionnaire asked were recorded on the format right on the spot. Results: Gender was found to be a significant risk factor for the Toxocara infection in children population. Male children were found more infected (41.71% as compared to females (24.16%. The total seroprevalence of T. canis antibodies in children of East Azerbaijan Province was 29.46 %. The risk factors that were found associated with the infection of toxocariasis in children population of East Azerbaijan Province include family back ground, status of living conditions, awareness, etc. Conclusion: The present study reveals high prevalence of T. canis infection in children of East Azerbaijan Province. It is important to raise the awareness of health professionals, public and educators to the fact that toxocariasis is a public health problem. Health promotion by means of a school based educational approach, diagnosis and continuous programme of treatment are necessary. [Cukurova Med J 2013; 38(4.000: 581-586

  16. Recent LHCD experiments in EAST

    International Nuclear Information System (INIS)

    Ding, B.J.

    2013-01-01

    LHCD system of 2.45 GHz in EAST has been updated to 4MW in last campaign. Aimed at high confinement (H-mode) plasma in EAST, the LHW-plasma coupling and current drive experiments were continued. Experiments of local gas puffing near LHW antenna shows that gas puffing from electron side is better to improve LHW-plasma coupling than that from ion side. LHCD experiments at high density are also performed, demonstrating that the decrease of current efficiency at high density may be related to the parametric decay instability (PDI) effect. Lithiation and local gas puffing near LHW antenna are utilized so as to sustain H-mode plasma. H-mode plasma is obtained by LHCD with a wide range of parameters: Ip=0.4∼0.8MA, B_t=1.35∼1.81T, n_e=1.5∼2.5x10"1"9 m"-"3, P_L_H_W>=0.5MW. LHW power deposition and driven current profile with C3PO/LUKE are calculated with the experimental parameters, showing that central and large driven current seems not a necessary condition for the H-mode plasma. H-mode is reproduced with CRONOS. Long pulse plasmas, >400s L mode fully driven by LHCD and >30s H-mode with LHCD and ICRF, have been achieved and demonstrated in EAST. (author)

  17. Formative (measurement)

    NARCIS (Netherlands)

    Fassott, G.; Henseler, Jörg; Cooper, C.; Lee, N.; Farrell, A.

    2015-01-01

    When using measurement models with multiple indicators, researchers need to decide about the epistemic relationship between the latent variable and its indicators. In this article, we describe the nature, the estimation, the characteristics, and the validity assessment of formative measurement

  18. Organic chemistry and petrology of barven and Mo-Ni-PGE mineralized marine black Thales of the Lower Cambrian Niutitang Formation (South China)

    Czech Academy of Sciences Publication Activity Database

    Kříbek, B.; Sýkorová, Ivana; Pašava, J.; Machovič, Vladimír

    2007-01-01

    Roč. 72, 3-4 (2007), s. 240-256 ISSN 0166-5162 R&D Projects: GA AV ČR IAA300460510 Institutional research plan: CEZ:AV0Z30460519 Keywords : organic particles * reflectance * micro-Raman spectra Subject RIV: DD - Geochemistry Impact factor: 1.625, year: 2007

  19. Petrography and diagensis of Padeha Formation sandstones (Lower-Middle Devonian at Bujhan section, Binalud Basin, NE Iran

    Directory of Open Access Journals (Sweden)

    Mehdi Reza Poursoltani

    2016-12-01

    Conclusion: Based on petrological and geochemical studies, minor diagenetic events in the eodiagenetic stage include cementation (calcite, dolomite and iron oxide and rarely fracturing. Mesodiagenetic events were dominated by cementation (silica, dolomite, calcite, iron oxide components, clay minerals, compaction, intra-grain microfractures, alteration of unstable clasts, dissolution and replacement, pressure solution, and rarely formation of apatite. Minor telodiagenetic events include dissolution and cementation (dolomite, ankerite, siderite, iron oxide and rarely kaolinite. The bulk of the porosity is secondary, with an average of 4.7%, which is the result of dissolution and fractures

  20. Sedimentary Petrology: from Sorby to the globalization of Sedimentary Geology; La Petrologia Sedimentaria: desde Sorby a la globalizacion de la Geologia Sedimentaria

    Energy Technology Data Exchange (ETDEWEB)

    Alonso-Zarza, A M

    2013-02-01

    We describe here the most important milestones and contributions to Sedimentary Petrology compared to other geological disciplines. We define the main aim of our study and the scientific and economic interests involved in Sedimentary Petrology. The body of the paper focuses upon the historical development of this discipline from Henry Sorby's initial work until the present day. The major milestones in its history include: 1) initial descriptive works; 2) experimental studies; 3) the establishment of the different classifications of sedimentary rocks; 4) studies into facies and sedimentary environments; 5) advances in the study of diagenetic processes and their role in hydrocarbon prospection; and 6) the development of Sedimentary Geochemistry. Relationships and coincidences with Sedimentology are discussed. We go on to look at the advances that have taken place over the last 30 years, in which the study of sedimentary rocks is necessarily included in the wider field of Sedimentary Geology as a logical result of the proposal of global models of a changing Earth in which Sedimentary Geology plays a significant part. Finally we mention the notable contributions of Spanish sedimentary petrologists to this whole field of science. (Author) 120 refs.

  1. Magma transport and storage at Mt. Etna (Italy): A review of geodetic and petrological data for the 2002-03, 2004 and 2006 eruptions

    Science.gov (United States)

    Palano, Mimmo; Viccaro, Marco; Zuccarello, Francesco; Gresta, Stefano

    2017-11-01

    A detailed reconstruction of magma movements within the plumbing system of Mt. Etna volcano has been made by reviewing the eruptions occurring during the October 2002-December 2006 period. The availability of continuous GPS data allowed detecting at least ten different ground deformation stages, highlighting deflationary and inflationary episodes as well as the occurrence of a shallow dike intrusion. These data have been coupled with the available petrological datasets including major/trace elements and Sr-Nd-Pb isotope compositions for the volcanic rocks erupted in the 2002-2006 period. We identified two main magmatic reservoirs located at different depths along the plumbing system of the volcano. The former is located at a depth of 7 km bsl and fed the 2001 and 2002-03 eruptions, while the latter, located from 3.5 to 5.5 km bsl, fed the 2004-05 and 2006 eruptions. Petrological characteristics of emitted products have been correlated with the inflation vs. deflation cycles related to the identified sources, providing evidence for changes through time of the evolutionary degree of the erupted magmas along with variations in their geochemical feature. Finally, we suggest that a modification of the deep plumbing system of the volcano might have occurred during the 2002-03 eruption, as a consequence of the major seaward motion of the eastern flank of the volcano.

  2. Sedimentary Petrology: from Sorby to the globalization of Sedimentary Geology; La Petrologia Sedimentaria: desde Sorby a la globalizacion de la Geologia Sedimentaria

    Energy Technology Data Exchange (ETDEWEB)

    Alonso-Zarza, A. M.

    2013-02-01

    We describe here the most important milestones and contributions to Sedimentary Petrology compared to other geological disciplines. We define the main aim of our study and the scientific and economic interests involved in Sedimentary Petrology. The body of the paper focuses upon the historical development of this discipline from Henry Sorby's initial work until the present day. The major milestones in its history include: 1) initial descriptive works; 2) experimental studies; 3) the establishment of the different classifications of sedimentary rocks; 4) studies into facies and sedimentary environments; 5) advances in the study of diagenetic processes and their role in hydrocarbon prospection; and 6) the development of Sedimentary Geochemistry. Relationships and coincidences with Sedimentology are discussed. We go on to look at the advances that have taken place over the last 30 years, in which the study of sedimentary rocks is necessarily included in the wider field of Sedimentary Geology as a logical result of the proposal of global models of a changing Earth in which Sedimentary Geology plays a significant part. Finally we mention the notable contributions of Spanish sedimentary petrologists to this whole field of science. (Author) 120 refs.

  3. Organic petrology of subbituminous carbonaceous shale samples from Chalaw, Kabul Province, Afghanistan: Considerations for paleoenvironment and energy resource potential

    Energy Technology Data Exchange (ETDEWEB)

    Hackley, Paul C.; SanFilipo, John R. [U.S. Geological Survey, MS 956 National Center, Reston VA, 20192 (United States); Azizi, Gul Pacha [Afghanistan Geological Survey, Macroryan Square, Kabul (Afghanistan); Davis, Philip A. [U.S. Geological Survey, 520 N. Park Avenue, Tucson AZ, 85719 (United States); Starratt, Scott W. [U.S. Geological Survey, MS 910, 345 Middlefield Rd, Menlo Park CA, 94025 (United States)

    2010-04-01

    Neogene (?) subbituminous carbonaceous shale deposits from Chalaw, Afghanistan, were investigated through organic petrology techniques and standard coal analyses to determine paleoenvironment and potential for resource utilization. The Chalaw deposit, approximately 30 km southeast of Kabul, currently is exploited for brick making and domestic heating and cooking. Three multiple-bench channel samples of the mined bed at Chalaw were collected and evaluated. The presence of significant huminite (ranging from 0.2 to 59.0 vol.%, mineral-inclusive basis) is suggestive of a terrestrial lignin-rich precursor plant material. Measured reflectance values of 0.38-0.55% indicate subbituminous rank. This rank suggests burial depths of approximately 1500 m and maximum temperatures of approximately 50 C. Structured liptinite macerals generally are absent except for some fluorescing morphologies interpreted to be poorly-preserved root cork suberinite. Sponge spicule bioliths including gemmoscleres and megascleres are common. These petrographic observations, in addition to high mineral matter content (33 to > 95 vol.%), medium to high sulfur content (2.1-11.5 wt.%, dry basis; db), and the presence of common gastropod? shell fragments and an aragonite-needle chalk bed are consistent with, but not directly indicative of, a marginal marine or estuarine mangrove depositional environment. However, additional data are necessary to confirm this hypothesis and deposition in a freshwater environment cannot be ruled out at this time. Commercial-scale development and utilization of the Chalaw deposit as a thermal fuel resource may be possible using a fluidized bed combustion system which could accept the low-quality mine product currently produced. Samples examined herein contain high-ash yield (45-90 wt.%, db), high total moisture content (17-39 wt.%), low calorific value (980-6860 Btu/lb, m,mmf), and have poor agglomerating properties (FSI = 0), consistent with fuels utilized in fluidized

  4. Petrological and zircon evidence for the Early Cretaceous granulite-facies metamorphism in the Dabie orogen, China

    Science.gov (United States)

    Gao, Xiao-Ying; Zhang, Qiang-Qiang; Zheng, Yong-Fei; Chen, Yi-Xiang

    2017-07-01

    An integrated study of petrology, mineralogy, geochemistry, and geochronology was carried out for contemporaneous mafic granulite and diorite from the Dabie orogen. The results provide evidence for granulite-facies reworking of the ultrahigh-pressure (UHP) metamorphic rock in the collisional orogen. Most zircons from the granulite are new growth, and their U-Pb ages are clearly categorized into two groups at 122-127 Ma and 188 ± 2 Ma. Although these two groups of zircons show similarly steep HREE patterns and variably negative Eu anomalies, the younger group has much higher U, Th and REE contents and Th/U ratios, much lower εHf(t) values than the older group. This suggests their growth is associated with different types of dehydration reactions. The older zircon domains contain mineral inclusions of garnet + clinopyroxene ± quartz, indicating their growth through metamorphic reactions at high pressures. In contrast, the young zircon domains only contain a few quartz inclusions and the garnet-clinopyroxene-plagioclase-quartz barometry yields pressures of 4.9 to 12.5 kb. In addition, the clinopyroxene-garnet Fe-Mg exchange thermometry gives temperatures of 738-951 °C. Therefore, the young zircon domains would have grown through peritectic reaction at low to medium pressures. The younger granulite-facies metamorphic age is in agreement not only with the adjacent diorite at 125 ± 1 Ma in this study but also the voluminous emplacement of coeval mafic and felsic magmas in the Dabie orogen. Mineral separates from both mafic granulite and its adjacent diorite show uniformly lower δ18O values than normal mantle, similar to those for UHP eclogite-facies metaigneous rocks in the Dabie orogen. In combination with major-trace elements and zircon Lu-Hf isotope compositions, it is inferred that the protolith of mafic granulites shares with the source rock of diorites, both being a kind of mafic metasomatites at the slab-mantle interface in the continental subduction channel

  5. Salt formations offer disposal alternative

    International Nuclear Information System (INIS)

    Funderburk, R.

    1990-01-01

    This paper discusses how three U.S. firms are spending millions to permit and build underground disposal sites in salt formations. These companies claim salt is the ideal geological medium for holding hazardous wastes. Two Texas locations and one in Michigan have been targeted as future sites for hazardous waste disposal. The Michigan site, outside Detroit, is a former salt mine 2,000 feet beneath the Ford Motor Co. (Detroit) assembly works in Dearborn. Both Texas sites are atop salt domes---one east and one west of Houston

  6. Cement Formation

    DEFF Research Database (Denmark)

    Telschow, Samira; Jappe Frandsen, Flemming; Theisen, Kirsten

    2012-01-01

    Cement production has been subject to several technological changes, each of which requires detailed knowledge about the high multiplicity of processes, especially the high temperature process involved in the rotary kiln. This article gives an introduction to the topic of cement, including...... an overview of cement production, selected cement properties, and clinker phase relations. An extended summary of laboratory-scale investigations on clinkerization reactions, the most important reactions in cement production, is provided. Clinker formations by solid state reactions, solid−liquid and liquid......−liquid reactions are discussed, as are the influences of particles sizes on clinker phase formation. Furthermore, a mechanism for clinker phase formation in an industrial rotary kiln reactor is outlined....

  7. Star formation

    International Nuclear Information System (INIS)

    Woodward, P.R.

    1978-01-01

    Theoretical models of star formation are discussed beginning with the earliest stages and ending in the formation of rotating, self-gravitating disks or rings. First a model of the implosion of very diffuse gas clouds is presented which relies upon a shock at the edge of a galactic spiral arm to drive the implosion. Second, models are presented for the formation of a second generation of massive stars in such a cloud once a first generation has formed. These models rely on the ionizing radiation from massive stars or on the supernova shocks produced when these stars explode. Finally, calculations of the gravitational collapse of rotating clouds are discussed with special focus on the question of whether rotating disks or rings are the result of such a collapse. 65 references

  8. Galaxy Formation

    DEFF Research Database (Denmark)

    Sparre, Martin

    Galaxy formation is an enormously complex discipline due to the many physical processes that play a role in shaping galaxies. The objective of this thesis is to study galaxy formation with two different approaches: First, numerical simulations are used to study the structure of dark matter and how...... galaxies form stars throughout the history of the Universe, and secondly it is shown that observations of gamma-ray bursts (GRBs) can be used to probe galaxies with active star formation in the early Universe. A conclusion from the hydrodynamical simulations is that the galaxies from the stateof...... is important, since it helps constraining chemical evolution models at high redshift. A new project studying how the population of galaxies hosting GRBs relate to other galaxy population is outlined in the conclusion of this thesis. The core of this project will be to quantify how the stellar mass function...

  9. Comet formation

    Science.gov (United States)

    Blum, J.

    2014-07-01

    There has been vast progress in our understanding of planetesimal formation over the past decades, owing to a number of laboratory experiments as well as to refined models of dust and ice agglomeration in protoplanetary disks. Coagulation rapidly forms cm-sized ''pebbles'' by direct sticking in collisions at low velocities (Güttler et al. 2010; Zsom et al. 2010). For the further growth, two model approaches are currently being discussed: (1) Local concentration of pebbles in nebular instabilities until gravitational instability occurs (Johansen et al. 2007). (2) A competition between fragmentation and mass transfer in collisions among the dusty bodies, in which a few ''lucky winners'' make it to planetesimal sizes (Windmark et al. 2012a,b; Garaud et al. 2013). Predictions of the physical properties of the resulting bodies in both models allow a distinction of the two formation scenarios of planetesimals. In particular, the tensile strength (i.e, the inner cohesion) of the planetesimals differ widely between the two models (Skorov & Blum 2012; Blum et al. 2014). While model (1) predicts tensile strengths on the order of ˜ 1 Pa, model (2) results in rather compactified dusty bodies with tensile strengths in the kPa regime. If comets are km-sized survivors of the planetesimal-formation era, they should in principle hold the secret of their formation process. Water ice is the prime volatile responsible for the activity of comets. Thermophysical models of the heat and mass transport close to the comet-nucleus surface predict water-ice sublimation temperatures that relate to maximum sublimation pressures well below the kPa regime predicted for formation scenario (2). Model (1), however, is in agreement with the observed dust and gas activity of comets. Thus, a formation scenario for cometesimals involving gravitational instability is favored (Blum et al. 2014).

  10. Petrology of blueschist and meta-greywacke along the Turkmeni-Ordib fault (Turkmeni area, SE of Anarak

    Directory of Open Access Journals (Sweden)

    Fereshteh Bayat

    2015-10-01

    Full Text Available Introduction The occurrence of blueschist metamorphic facies is believed to mark the existence of former subduction zones. This facies is represented in the main constituents of subduction-accretion complexes, where it occurs in separate tectonic sheets, imbricated slices, lenses, or exotic blocks within a serpentinite mélange (Volkova et al., 2011. The evidence of the presence and maturity of Paleo- Tethys oceanic crust in the CEIM (define this in Paleo-Tethys branches, subduction and collision has been studied by various authors (Bagheri, 2007; Zanchi et al., 2009; Bayat and Torabi, 2011; Torabi 2011. Late Paleozoic blueschists have recognized in the western part of the CEIM (e. g. Anarak, Chupanan and Turkmeni in linear trends. Metamorphic rocks of the Turkmeni area (SE of Anarak are composed of blueschist and meta-greywacke and are situated along the Turkmeni-Ordib fault associated with Paleozoic rock units and serpentinized peridotite bodies. Turkmeni blueschist and meta-greywackes have not been studied by previous workers. The Turkmeni blueschists consist of albite, winchite, actinolite and epidote. Granoblastic, nematoblastic and lepidoblastic are main textures in these rocks. Winchite is found in the matrix and around epidote grains. This sodic-calcic amphibole serves as an index mineral in blueschist facies. Actinolite and epidote formed during retrograde metamorphism of blueschists in the greenschist facies. The mineral assemblage of albite, epidote, chlorite and phengite ± garnet is present in meta-greywackes in the Turkmeni blueschists. Veins of garnet, muscovite, quartz and opaque minerals are extensive in these rocks. Epidote and chlorite formed in meta-greywackes by retrograde metamorphism in the greenschist facies. The aim of the present study is to determine the petrological and geochemical characteristics, P-T condition of blueschists and meta-greywackes, as well as the geotectonic setting of primary basaltic rocks of the

  11. The Middle East population puzzle.

    Science.gov (United States)

    Omran, A R; Roudi, F

    1993-07-01

    An overview is provided of Middle Eastern countries on the following topics; population change, epidemiological transition theory and 4 patterns of transition in the middle East, transition in causes of death, infant mortality declines, war mortality, fertility, family planning, age and sex composition, ethnicity, educational status, urbanization, labor force, international labor migration, refugees, Jewish immigration, families, marriage patterns, and future growth. The Middle East is geographically defined as Bahrain, Egypt, Iraq, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, Syria, United Arab Emirates, Yemen, Gaza and the West Bank, Iran, Turkey, and Israel. The Middle East's population grew very little until 1990 when the population was 43 million. Population was about doubled in the mid-1950s at 80 million. Rapid growth occurred after 1950 with declines in mortality due to widespread disease control and sanitation efforts. Countries are grouped in the following ways: persistent high fertility and declining mortality with low to medium socioeconomic conditions (Jordan, Oman, Syria, Yemen, and the West Bank and Gaza), declining fertility and mortality in intermediate socioeconomic development (Egypt, Lebanon, Turkey, and Iran), high fertility and declining mortality in high socioeconomic conditions (Bahrain, Iraq, Kuwait, Qatar, Saudi Arabia, and the United Arab Emirates), and low fertility and mortality in average socioeconomic conditions (Israel). As birth and death rates decline, there is an accompanying shift from communicable diseases to degenerative diseases and increases in life expectancy; this pattern is reflected in the available data from Egypt, Kuwait, and Israel. High infant and child mortality tends to remain a problem throughout the Middle East, with the exception of Israel and the Gulf States. War casualties are undetermined, yet have not impeded the fastest growing population growth rate in the world. The average fertility is 5 births

  12. Padrt'stock (Teplá–Barrandian unit, Bohemian Massif): Petrology, geochemistry, U-Pb zircon dating of granodiorite, and Re-Os age and origin of related molybdenite mineralization

    Czech Academy of Sciences Publication Activity Database

    Žák, Karel; Svojtka, Martin; Breiter, Karel; Ackerman, Lukáš; Zachariáš, J.; Pašava, J.; Veselovský, F.; Litochleb, J.; Ďurišová, Jana; Haluzová, Eva

    2014-01-01

    Roč. 59, č. 4 (2014), s. 351-366 ISSN 1802-6222 R&D Projects: GA ČR GA13-15390S Institutional support: RVO:67985831 Keywords : geochemistry * petrology * Re–Os molybdenite dating * Teplá–barrandian unit * U–Pb zircon dating * Variscan granitoids Subject RIV: DD - Geochemistry Impact factor: 1.405, year: 2014

  13. The Carboniferous to Jurassic evolution of the pre-Alpine basement of Crete: Constraints from U-Pb and U-(Th)-Pb dating of orthogneiss, fission-track dating of zircon, structural and petrological data

    Czech Academy of Sciences Publication Activity Database

    Romano, S. S.; Brix, M. R.; Dörr, K.; Fiala, Jiří; Krenn, E.; Zulauf, G.

    2006-01-01

    Roč. 260, - (2006), s. 69-90 ISSN 0375-6440 Institutional research plan: CEZ:AV0Z30130516 Keywords : tectonic-evolution * Carboniferous * Jurassic * uranium-lead-dating * orthogneiss * fission-track-dating * zircon * structural-geology * petrology * metamorphism * high-temperature Subject RIV: DB - Geology ; Mineralogy

  14. Geochemical studies, magmatic evolution, microstructures and replacement mechanisms in Jebale-Barez granitoid Complex (East and Southeast Jiroft

    Directory of Open Access Journals (Sweden)

    Jamal Rasouli

    2017-08-01

    Full Text Available Introduction The Jebale-Barez Plutonic Complex (JBPC is composed of many intrusive bodies and is located in the southeastern province of Kerman on the longitude of the 57◦ 45 ' east to 58◦ 00' and Northern latitudes 28◦ 30' to 29◦ 00'. The petrologic composition is composed of granodiorite, quartzdiorite, granite, alkali-granite, and trace amounts of tonalite with dominant granodiorite composition. Previously, the JBPC was separated into three plutonic phases by Ghorbani (2014. The first plutonic phase is the main body of the complex with composition of quartz-diorite to granodiorite. After differentiation of magma in the magmatic chamber, the porphyritic and not fully consolidated magmas have intruded into the main body. Their compositions were dominantly granodiorite and granite that are defined as the second plutonic phase. Finally, the last phase was started by an intrusion of the holo- leucogranite into the previous bodies. This plutonic activity was pursued by the minor Quaternary basaltic volcanism that shows metamorphic haloes in the contacts. They are dominantly porphyric leucogranites. However, some bodies show dendritic texture that may imply the existence of silicic fluids in the latest crystallization stages. Materials and methods In this article different analysis methods were used. For example, we used a total of two hundred samples of the various granitoids that were selected for common thin section study. Forty four representative samples from the different granitic rocks were selected for whole rock chemical analyses. The analyses of both major and trace elements were performed at the Department of Earth Sciences, the University of Perugia, Italy. The analysis for all major elements was carried out by an X-ray fluorescence spectrometry (XRF using a tube completed with a Rn and W anode under conditions with acceleration voltage of 40-45 kV and electric current ranging from I=30-35 mA. After calcination of powdered

  15. A review of the platanaceous woods from the Eocene paratropical rainforest of south-east England

    NARCIS (Netherlands)

    Poole, I.J.; Davies, Kevin L.; Wilkinson, Hazel P.

    2002-01-01

    Small diameter pyritized axes, commonly referred to as ‘twigs’, of fossil platanaceous wood are described from the Lower Eocene London Clay Formation of south-east England. These twigs are characterized by solitary vessels with scalariform perforation plates, opposite intervessel pits, and tall,

  16. The East Midlands in 2006: the demography of the East Midlands

    OpenAIRE

    Lawton, C

    2006-01-01

    The East Midlands in 2006 is the evidence base that was produced to underpin the devleopment of the regional economic strategy, A Flourishing Region. This document presents detailed analysis of the demography of the East Midlands.

  17. Near East/South Asia Report

    National Research Council Canada - National Science Library

    1986-01-01

    .... This report from Near East/South Asia, Algeria, Sudan, Iraq, Israel, Kuwait, Saudi Arabia, Syria, Afghanistan, Bangladesh, India, Iran, and Pakistan, contains articles on Economics, Political Science...

  18. Near East/South Asia Report

    National Research Council Canada - National Science Library

    1986-01-01

    .... This report from Near East/South Asia, Egypt, Libya, Morocco, Tunisia, Israel, Jordan, Lebanon, Syria, Afghanistan, Bangladesh, and Iran contains articles on Political Science, Economics, Regional...

  19. Near East/South Asia Report

    National Research Council Canada - National Science Library

    1986-01-01

    .... This report from Near East/South Asia, Egypt, Libya, Tunisia, Israel, Afghanistan, Bangladesh, Iran, Iraq, and Pakistan contains articles on International, Regional, Political and Economic Issues...

  20. Near East/South Asia Report

    National Research Council Canada - National Science Library

    1986-01-01

    .... This report from the Near East/South Asia, Algeria, Egypt, Tunisia, Israel, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, Afghanistan and Iran, contains articles on International Affairs, Politics...

  1. Near East/South Asia Report

    National Research Council Canada - National Science Library

    1986-01-01

    .... This report contains articles on the Near East/South Asia, Egypt, Mauritania, Morocco, Tunisia, Israel, Jordan, Kuwait, Oman, Saudi Arabia, United Arab Emirates, Afghanistan, Iran and Pakistan...

  2. The New District of East Belitung: the Review Poliferation Process

    Directory of Open Access Journals (Sweden)

    Hendri Yani

    2013-02-01

    Full Text Available The regional autonomy conducted in many functions of government. One of its forms is proliferation of region. The aim of this study was to overview the proceed of proliferation in East Belitung District. This research was a qualitative research consisted of two main techniques to collect the data; they were interview and secondary data from documentations. The findings show that there were ten steps to create the new East Belitung District. The steps started from the preparations of local’s planning and administration to the final steps in the hand of national parliaments. This study found that the number of local government in Indonesia has increases, and the process at the central government level seem relatively easy. But, the eligibility criteria being compromised. Then, the political will from communities were not clear mention. Also there was a conflict interest between local government and central government in the feasibility study for proliferation in Belitung District. It concluded that we could not deny that political intervention in the bureaucracy has facilitated the formation of East Belitung districts.

  3. Regional economic integration in Great East Asia: determinants and barriers

    Directory of Open Access Journals (Sweden)

    Volodymyr Korol

    2015-06-01

    Full Text Available The article studies both general trends and peculiar characteristics of processes of economic integration in the Great East Asia, which plays the role of one of the major centers of contemporary global development. The basic determinants and barriers for implementation of regional strategies by China, Japan, ASEAN that will influence the geo-economic policy of Ukraine not only in East Asian, but also European and Eurasian areas. Attention is focused on the basic principles of realized and potential future integration models in the "ASEAN+" format with variable composition of member states that correspond to different extents to strategic objectives of both specified key actors in the region and extra-regional states that have global and transnational interests. Extrapolation of dominant trends in the nature and dynamics of transformation processes of East Asian economic regionalization allowed forming a forecast for the longterm conservation of importance of free trade agreements in the absence of preconditions to create customs unions. At the same time it was stressed out that proper assurance of national interests of international economic relations will be based on contractual instruments at the international level, without creating institutional and legal superstructure similar to the European Union or the Eurasian Economic Union as supranational law and supranational bodies.

  4. East Carnduff Unit: corrosion problems

    Energy Technology Data Exchange (ETDEWEB)

    Banks, C D

    1966-07-01

    Waterflooding of the East Carnduff Unit began in late 1962. The first injection line leak was discovered April 29, 1965. The first 6 leaks in the East Carnduff Unit occurred within a period of less than one month--a very startling and serious warning of pending problems. Analysis of the pipe removed showed a deep pit covered by a severe scale in the piping fitting. Several remedial actions were tried in order to develop the present inhibition program. First, the lines were cleaned as well as possible utilizing rubber pig spheres with normal injection pressure. This proved very effective and 2 passes wiped out most of the scale in the lines. Only one line required acid. After the lines had been cleaned, a water treating rate of an organic amine corrosion inhibitor, 10 ppm of the scale inhibitor, and bactericide at the rate of 40 ppm slugs 2 days per month was initiated. The above treating program is in use at the present time and is maintaining a very low leak frequency. This experience has demonstrated 2 important points in waterflood operations: (1) a bare piping system in warm brine service requires constant attention to insure that it is being kept clean; and (2) reliance cannot be placed on any one method of checking corrosion rates.

  5. Alien smuggling: East to West.

    Science.gov (United States)

    Walsh, J H

    1987-01-01

    This year untold millions of illegal aliens will enter Western Europe, Canada, and the US; in 1986, the US alone made 1.7 million apprehensions. Because of the numbers involved and the hard currency exchanged, alien smuggling has become big business--a lucrative track in desparate human beings. West Germany's open door asylum policy has been a boon to the smugglers, and West Berlin is currently a favored port of entry. The government provides social benefits--apartments, food, a stipend, and clothing--for asylum seekers. Smuggling operations appear to fit 3 categories: 1) state-sponsored alien smugglers, with a sub-category of terrorists; 2) ethnic smugglers with a history of terrorist spinoffs; and 3) independent smugglers, who are profit oriented, and willing to handle ethnic aliens and terrorists. In West Germany, immigration investigations begin at the border. West German officials often know that as they cause the Eastern border to be tightened, the flow will gravitate south toward Austria. Redirecting the trasit of Third Worlders from East Berlin away from West Germany, Sweden, and Denmark will be a stop-gap measure at best. Part of West Germany's immigration problem can be traced to the Basic Law that provides asylum for those who claim persecution (political, racial, ethnic, or religious). Yet, any attempt to change asylum would result in an admission of defeat in the quest for a unified Germany. Should Austria move to tighten its immigration laws, agreements similar to those between East and West Germany will likely follow.

  6. Middle East oil and gas

    International Nuclear Information System (INIS)

    1995-01-01

    This study is intended to shed light on structural changes occurring in six Middle East countries (Iran, Iraq, Kuwait, Qatar, Saudi Arabia and the United Arab Emirates) that can be expected to have a significant impact on their oil and gas industry. These six countries provide 42% of the world's traded crude oil, on which Member countries of the International Energy Agency (IEA) are increasingly dependent. They also contain about 65% and 30% of the world's proven oil and natural gas reserves, respectively, and command a strategic location between Europe and Asia. The Middle East has been one of the most volatile parts of the world where war, revolution and embargoes have caused major upheavals that have led to oil supply disruptions. The oil resources of all six countries were initially developed by international oil companies and all are members of the Organization of the Petroleum Exporting Countries (OPEC). In 1994, their crude oil production capacity was about 23 million barrels per day (mbd) and is planned to expand to about 28 mbd by the year 2000. Revenue from the sale of oil accounts for more than 80% of each nation's total exports and about 75% of each government's income. The objectives of this study are: to detail their announced oil and gas development plans, to describe the major trends occurring in these countries, to outline the government responses to the trends, and to analyse the impact of government policies on oil and gas development. (J.S.). 121 refs., 136 figs., 212 tabs

  7. Petrology of Olkiluoto

    International Nuclear Information System (INIS)

    Kaerki, A.; Paulamaeki, S.

    2006-11-01

    The rocks of Olkiluoto fall into four main groups: (1) gneisses, (2) migmatitic gneisses, (3) TGG-gneisses (TGG = tonalite-granodiorite-granite) and 4) pegmatitic granites. In addition, narrow diabase dykes occur sporadically. The gneisses include homogeneous mica-bearing quartz gneisses, banded mica gneisses and hornblende or pyroxene-bearing mafic gneisses. The migmatitic gneisses, which typically comprise 20 - 40% leucosome, can be divided into three subgroups in terms of their migmatite structures: veined gneisses, stromatic gneisses and diatexitic gneisses. The leucosomes of the veined gneisses show vein-like, more or less elongated traces with some features similar to augen structures. Planar leucosome layers characterize the stromatic gneisses, while the migmatite structure of the diatexitic gneisses is asymmetric and irregular. The TGG gneisses are medium-grained, relatively homogeneous rocks that can show a blastomylonitic foliation, but they can also resemble plutonic, unfoliated rocks. The pegmatitic granites are leucocratic, very coarse-grained rocks, which may contain large garnet, tourmaline and cordierite phenocrysts. Mica gneiss inclusions are typical of the larger pegmatitic bodies. Gneisses, which are weakly or not at all migmatitic, make ca. 9% of the bedrock. Migmatitic gneisses make up over 64% of the volume of the Olkiluoto bedrock, with the veined gneisses accounting for 43%, the stromatic gneisses for 0.4% and the diatexitic gneisses for 21%, based on drill core logging. Of the remaining lithologies, TGG gneisses constitute 8% and pegmatitic granites almost 20% by volume. The supracrustal rocks of Olkiluoto can be divided into four series by reference to whole rock chemical composition: a T series, S series, P series and basic, volcanogenic gneisses. Rocks of the T, S and P series seem to make up 42%, 12% and 26%, respectively, of the volume of central part of the island of Olkiluoto, in addition to which, pegmatitic granites and diabases form groups of their own that can be identified both macroscopically and chemically. The rocks of the T series are various veined gneisses and diatexitic gneisses, together with various mica gneisses and quartz gneisses. One typical feature of this series is the occurrence of strongly pinitized cordierite and sometimes also a small proportion of sillimanite. The T series is an transition series, the end members of which are relatively dark and often cordierite-bearing mica gneisses and migmatites with less than 60% SiO 2 and quartz gneisses with more than 75% SiO 2 , representing clay mineral-rich pelitic materials and greywacke-type impure sandstones, respectively. Certain TGG gneisses that are typically granitic in their modal mineral composition show a chemical similarity to the members of the T series. The members of the S series may be identified from their textures and mineral compositions as quartz gneisses, mica gneisses, migmatites and mafic gneisses. The most essential difference between these and the members of the other series is their high calcium concentration, the figure typically exceeding 2%, with maximum concentrations over 13%, while those in the T series are below 2%. A relatively low alkali content and high manganese content are also typical of this series, the members of which are assumed to have originated from calcareous sedimentary materials. The members of the P series are TGG gneisses, veined gneisses, diatexitic gneisses, mafic gneisses and mica gneisses typically with a small proportion of leucosome. These stand out from the other series by virtue of their high phosphorus content. P2O 5 concentrations exceeding 0.3% are characteristic of the members of the P series, whereas the other common supracrustal rock types at Olkiluoto contain less than 0.2% P2O 5 . Mafic gneisses and metadiabases not included in the above-mentioned three series are represented only by a couple of samples, the characteristic chemical variables of which are high MgO, alkalis, TiO 2 and P2O 5 . The chemical compositions of these rocks resemble those of picrites or picritic basalts. (orig.)

  8. Polychronous Zirconology of Navysh Volcanics of the Ai Formation (Southern Urals)

    Science.gov (United States)

    Krasnobaev, A. A.; Puchkov, V. N.; Sergeeva, N. D.

    2018-01-01

    In order to resolve the age of Navysh volcanics (NV), which is usually attributed to the Lower Riphean of the Ai Formation, we have used geochronological, petrologic, and mineralogical methods of zirconology, apart from the SHRIMP isotopic data of single zircon grains. Moreover, TIMS isotope age analyses have been conducted, the results of which can be regarded as both controlling and providing the most correct information. The TIMS and SHRIMP data make it possible to suggest a polychronous character of the NV, which include not only Riphean, but also Paleozoic groups of volcanics. In this situation, an assessment of the scales of such polychroneity of NV and, correspondingly, of the Ai Formation as a whole becomes urgent.

  9. The late Cainozoic East Antarctic ice sheet

    International Nuclear Information System (INIS)

    Colhoun, E.A.

    1999-01-01

    A review, mainly of East Antarctic late Cainozoic (post 40 Ma) geological and geomorphological evidence, supports the hypothesis of the continuous presence of an ice sheet, of about the present size, since the late Miocene. Evidence is presented and the view advanced that, during the late Wisconsin maximum of isotope stage 2, ice was not nearly as thick or extensive over the continental shelf as required by the model of 'maximum' Antarctic glaciation. Some of the factors influencing the contribution of Antarctica to post-glacial sea-level rise are discussed. It is considered that Antarctica's contribution was probably considerably less than previously estimated. The dating of marine and freshwater sequences in the Vestfold and Bunger Hills is consistent with deglaciation around the Pleistocene Holocene boundary, after the Late Wisconsin maximum. A date of ∼25 ka BP from permafrost in the Larsemann Hills means that either the Larsemann Hills were not glaciated during the Late Wisconsin or the ice failed to erode much of the permafrost surface. The degree of weathering of rock and glacial drifts in the Vestfold, Larsemann and Bunger Hills suggests a long time for formation, perhaps considerably longer than indicated by the dated marine and freshwater sediment sequences. Cosmogenic isotope dating in the Vestfold Hills has provided equivocal ages for deglaciation. While the results could indicate deglaciation before 80 ka BP, they do not confirm such early deglaciation. If the ice cover was thin and failed to remove the previous rock exposure profile, then the assays could predate the last ice advance. Weathered iron crust fragments in the till suggest little erosion. The raised beaches of the oases are Holocene. Assuming they have been produced by post Late Wisconsin isostatic uplift and by the Holocene transgression, calculations show that the Antarctic continental ice sheet could not have been more than ∼500 m thicker in the inner shelf-coastal zone. The

  10. Geochemical, microtextural and petrological studies of the Samba prospect in the Zambian Copperbelt basement: a metamorphosed Palaeoproterozoic porphyry Cu deposit.

    Science.gov (United States)

    Master, Sharad; Mirrander Ndhlovu, N.

    2015-04-01

    Ever since Wakefield (1978, IMM Trans., B87, 43-52) described a porphyry-type meta-morphosed Cu prospect, the ca 50 Mt, 0.5% Cu Samba deposit (12.717°S, 27.833°E), hosted by porphyry-associated quartz-sericite-biotite schists in northern Zambia, there has been controversy about its origin and significance. This is because it is situated in the basement to the world's largest stratabound sediment-hosted copper province, the Central African Copperbelt, which is hosted by rocks of the Neoproterozoic Katanga Supergroup. Mineralization in the pre-Katangan basement has long played a prominent role in ore genetic models, with some authors suggesting that basement Cu mineralization may have been recycled into the Katangan basin through erosion and redeposition, while others have suggested that the circulation of fluids through Cu-rich basement may have leached out the metals which are found concentrated in the Katangan orebodies. On the basis of ca 490-460 Ma Ar-Ar ages, Hitzman et al. (2012, Sillitoe Vol., SEG Spec. Publ., 16, 487-514) suggested that Samba represents late-stage impregnation of copper mineralization into the basement, and that it was one of the youngest copper deposits known in the Central African Copperbelt. If the Samba deposit really is that young, then it would have post-dated regional deformation and metamorphism (560-510 Ma), and it ought to be undeformed and unmetamorphosed. The Samba mineralization consists of chalcopyrite and bornite, occurring as disseminations, stringers and veinlets, found in a zone >1 km along strike, in steeply-dipping lenses up to 10m thick and >150m deep. Our new major and trace element XRF geochemical data (14 samples) show that the host rocks are mainly calc-alkaline metadacites. Cu is correlated with Ag (Cu/Ag ~10,000:1) with no Au or Mo. Our study focused on the microtextures and petrology of the Samba ores. We confirm that there is alteration of similar style to that accompanying classical porphyry Cu mineralization

  11. A new tool for virtual scientific and autostereoscopic visualization of EAST

    International Nuclear Information System (INIS)

    Li, Dan; Xiao, B.J.; Xia, J.Y.; Wang, K.R.; Chen, S.L.; Luo, W.L.

    2016-01-01

    Highlights: • 3D effect of the virtual EAST has been improved and data visualization has been realized in the ASEAST system. • Interaction behavior is created that the users can get information from database. • The system integrates data acquisition, data visualization and model visualization. • QT libraries are adopted to realize the cross-platform and impressive graphical interface. • In order to manage the models, the web-based model manager system is constructed. - Abstract: The Experimental Advanced Superconducting Tokamak (EAST) Device began operation in 2006. EAST visualization work has been paid more and more attention for simulating its running state and inner structure. The VEAST system had been developed to display the 3D model of EAST facility and some diagnostic data based on Java3D. Compared with the VEAST system, a new system named autosterescopic scientific EAST (ASEAST) using C/S (Client/Server) structure in combination with the technology of OpenGL and an open-source software system for 3D computer graphics and visualization called VTK (Visualization Toolkit) and the Qt5 libraries for the graphical user interface (GUI) has been developed to improve the 3D effect of the virtual EAST and visualize the experimental data. The ASEAST can be used to get access to the information of EAST and physical properties. In addition, as a general system, ASEAST supports a wide variety of 3D formats. The visualization result can be output in the corresponding format of the input. In order to improve the rendering speed, we used the classic QEM algorithm to simplify the models in preprocess stage. As for the 3D effect, we made an investigation and the survey revealed that the system had good 3D effect.

  12. A new tool for virtual scientific and autostereoscopic visualization of EAST

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dan, E-mail: lidan@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui (China); Xiao, B.J.; Xia, J.Y.; Wang, K.R. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui (China); University of Science and Technology of China, Hefei, Anhui (China); Chen, S.L. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui (China); Luo, W.L. [709th Research lnstitute, China Shipbuilding lndustry Corporation, Wuhan, Hubei (China)

    2016-11-15

    Highlights: • 3D effect of the virtual EAST has been improved and data visualization has been realized in the ASEAST system. • Interaction behavior is created that the users can get information from database. • The system integrates data acquisition, data visualization and model visualization. • QT libraries are adopted to realize the cross-platform and impressive graphical interface. • In order to manage the models, the web-based model manager system is constructed. - Abstract: The Experimental Advanced Superconducting Tokamak (EAST) Device began operation in 2006. EAST visualization work has been paid more and more attention for simulating its running state and inner structure. The VEAST system had been developed to display the 3D model of EAST facility and some diagnostic data based on Java3D. Compared with the VEAST system, a new system named autosterescopic scientific EAST (ASEAST) using C/S (Client/Server) structure in combination with the technology of OpenGL and an open-source software system for 3D computer graphics and visualization called VTK (Visualization Toolkit) and the Qt5 libraries for the graphical user interface (GUI) has been developed to improve the 3D effect of the virtual EAST and visualize the experimental data. The ASEAST can be used to get access to the information of EAST and physical properties. In addition, as a general system, ASEAST supports a wide variety of 3D formats. The visualization result can be output in the corresponding format of the input. In order to improve the rendering speed, we used the classic QEM algorithm to simplify the models in preprocess stage. As for the 3D effect, we made an investigation and the survey revealed that the system had good 3D effect.

  13. Massive job cuts threaten East German science

    CERN Multimedia

    Hamer, M

    1990-01-01

    German reunification could result in thousands of scientists losing their jobs. At the end of this year the East German state budget for science will run out. Scientists in the East are keen to find Western support to protect their research (1 page).

  14. Journal of East African Natural History

    African Journals Online (AJOL)

    The Journal of East African Natural History is published jointly by the East Africa Natural History Society and the National Museums of Kenya. The Journal publishes papers and notes in the field of natural history, broadly defined as the study of organisms in their natural state, relevant to the eastern African region.

  15. Cultural Foundations of Learning: East and West

    Science.gov (United States)

    Li, Jin

    2012-01-01

    Western and East Asian people hold fundamentally different beliefs about learning that influence how they approach child rearing and education. Reviewing decades of research, Dr. Jin Li presents an important conceptual distinction between the Western mind model and the East Asian virtue model of learning. The former aims to cultivate the mind to…

  16. Green chemistry education in the Middle East

    Science.gov (United States)

    Kolopajlo, Larry

    2017-06-01

    The Middle East once dominated the age of alchemy, and today it is experiencing a resurgence by transforming the age of petroleum chemicals into a greener science through Estidama. This green conversion is taking place through green chemical research and education. This report examines and reviews the understudied subject of green chemical education in the Middle East through the lens of context and history.

  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. An experimental and petrologic investigation of the source regions of lunar magmatism in the context of the primordial differentiation of the moon

    Science.gov (United States)

    Elardo, Stephen M.

    The primordial differentiation of the Moon via a global magma ocean has become the paradigm under which all lunar data are interpreted. The success of this model in explaining multiple geochemical, petrologic, and isotopic characteristics lunar geology has led to magma oceans becoming the preferred model for the differentiation of Earth, Mars, Mercury, Vesta, and other large terrestrial bodies. The goal of this work is to combine petrologic analyses of lunar samples with high pressure, high temperature petrologic experiments to place new and detailed constraints the petrogenetic processes that operated during different stages of lunar magmatism, the processes that have acted upon these magmas to obscure their relationship to their mantle source regions, and how those source regions fit into the context of the lunar magma ocean model. This work focuses on two important phases of lunar magmatism: the ancient crust-building plutonic lithologies of the Mg-suite dating to ~4.3 Ga, and the most recent known mare basaltic magmas dating to ~3 Ga. These samples provide insight into the petrogenesis of magmas and interior thermal state when the Moon was a hot, juvenile planet, and also during the last gasps of magmatism from a cooling planet. Chapter 1, focusing on Mg-suite troctolite 76535, presents data on chromite symplectites, olivine-hosted melt inclusions, intercumulus mineral assemblages, and cumulus mineral chemistry to argue that the 76535 was altered by metasomatism by a migrating basaltic melt. This process could effectively raise radioisotope systems above their mineral-specific blocking temperatures and help explain some of the Mg-suite-FAN age overlap. Chapter 2 focuses on lunar meteorites NWA 4734, 032, and LAP 02205, which are 3 of the 5 youngest igneous samples from the Moon. Using geochemical and isotopic data combined with partial melting models, it is shown that these basalts do not have a link to the KREEP reservoir, and a model is presented for low

  19. Petrological and geochemical Highlights in the floating fragments of the October 2011 submarine eruption offshore El Hierro (Canary Islands): Relevance of submarine hydrothermal processes

    Science.gov (United States)

    Rodriguez-Losada, Jose A.; Eff-Darwich, Antonio; Hernandez, Luis E.; Viñas, Ronaldo; Pérez, Nemesio; Hernandez, Pedro; Melián, Gladys; Martinez-Frías, Jesús; Romero-Ruiz, M. Carmen; Coello-Bravo, Juan Jesús

    2015-02-01

    This paper describes the main physical, petrological and geochemical features of the floating fragments that were emitted in the initial stages of the 2011-2012 submarine eruption off the coast of the Canarian island of El Hierro, located 380 km from the Northwest African Coast. It attempts to assess the potential of radiometric analyses to discern the intriguing origin of the floating fragments and the differences between their constituent parts. In this regard, the material that conforms the core of the fragments contains the largest concentration of uranium (U) ever found in volcanic rocks of the Canary Islands. This enrichment in U is not found in the content of thorium (Th), hence the floating fragments have an unusual U/Th ratio, namely equal to or larger than 3. Although the origin of this material is under discussion, it is proposed that the enrichment in U is the result of hydrothermal processes.

  20. Variability of thermohaline fields in the East China Sea

    Science.gov (United States)

    Moroz, V. V.; Bogdanov, K. T.

    2007-04-01

    Characteristic features of the water structure and dynamics in the East China Sea, which is the zone of the formation of the Kuroshio Current, are studied from a database of mean multiannual hydrological and meteorological characteristics gathered for more than a half-century period and the data of expeditionary observations in this region. Characteristic distinctions between the waters in different regions of the current zone are shown. It was found that the formation of the structure of the water in the current zone is affected by the variability of the water exchange via the straits of the Ryukyu Islands and by the supply of the shelf waters against the background of the climatic variability.

  1. Geochemistry Petrography, thermobarometry and investigation of magmatic series in Mirabad- Chehel Khane granitoid body (east of Bouin– Miandasht, Isfahan province

    Directory of Open Access Journals (Sweden)

    Seyed Mohsen Tabatabaei Manesh

    2017-11-01

    Full Text Available On the base of petrology, the Mirabad- Chehel Khane granitoid, east of Bouin-Miandasht, dominantly consists of syenogranite, monzogranite, alkali granite and granodiorites. The main minerals of these rocks are quartz, alkali feldspar (Orthoclase, plagioclase (Albite - Oligoclase, biotite, ± amphibole with minor amount of allanite, zircon, titanite, apatite, ± tourmaline.  The biotite from the granites are Fe-rich type (annite and primary magmatic in origin. The composition of the biotites studied principally falls in the calc-alkaline subduction related I-type granite on the tectonomagmatic discrimination diagrams, which stand on their major element oxides. Which is consistent with the nature of their host rocks. The studied amphiboles are classified as calcic (ferro-hornblende which points to the I-type nature of the granitoid.  The tourmaline composition plots on the schorl - foitite field. The temperature for the alteration, on the base of chlorite composition from the syenogranite, is estimated around 350°C and from the monzogranite rocks about 341°C.  Based on the application of Al-in amphibole, a 3 Kbar pressure was determined for the syenogranite unit corresponding to the depth of 8-11 Km for the emplacement of the pluton. Hornblende- plagioclase thermometer shows 694 to 700°C for the equilibrium of these two minerals.

  2. East Capital suunab investorid Venemaale / Gert Tiivas ; interv. Raivo Sormunen

    Index Scriptorium Estoniae

    Tiivas, Gert, 1973-

    2007-01-01

    Rootsi investeerimispanga East Capitali Balti regiooni juht Gert Tiivas soovitab investeerida Baltimaadest suurema potentsiaaliga riikide börsidele. Vt. samas: CV: Gert Tiivas; East Capitali fondid. Diagramm: East Capitali Venemaa fondis on enim raha

  3. 230Th-238U disequilibrium systematics in oceanic tholeiites from 210N on the East Pacific Rise

    International Nuclear Information System (INIS)

    Newman, S.; Finkel, R.C.; MacDougall, J.D.

    1983-01-01

    Significant disequilibrium occurs between 230 Th and its parent, 238 U, in a suite of fresh basalt glasses from the RISE Project study area at 21 0 N on the East Pacific Rise. The ( 230 Th/ 232 Th) activity ratios observed for eight of nine samples from the crest of the axis at this site are constant within analytical uncertainty, with a value of 1.22. This observed homogeneity of ( 230 Th/ 232 Th) has two possible interpretations. First, the measured ( 230 Th/ 232 Th) can be considered to indicate a mantle-source for the RISE basalts with Th/U of 2.5. This interpretation, however, conflicts with the proposed correlation between ( 230 Th/ 232 Th) and 87 Sr/ 86 Sr which predicts that ( 230 Th/ 232 Th) should equal 1.33 at the RISE site. A second possible interpretation is that radioactive decay of 230 Th, in the basalts themselves or in a magma chamber, has decreased ( 230 Th/ 232 Th) from 1.33 to the observed values. The required time span is 11,000 to > 100,000 years. However, petrologic arguments rule against long residence time in a magma chamber, and the spreading rate of this section of the East Pacific Rise (6 cm/yr) predicts that the maximum age for axis basalts is 27,000 years. Both interpretations of the measured ( 230 Th/ 232 Th) imply a low Th/U ratio for the RISE basalt source and suggest that the MORB source at this location is depleted in Th with respect to U relative to primitive mantle or bulk earth. (orig./WL)

  4. Imaging rifting at the lithospheric scale in the northern East African Rift using S-to-P receiver functions

    Science.gov (United States)

    Lavayssiere, A.; Rychert, C.; Harmon, N.; Keir, D.; Hammond, J. O. S.; Kendall, J. M.; Leroy, S. D.; Doubre, C.

    2017-12-01

    The lithosphere is modified during rifting by a combination of mechanical stretching, heating and potentially partial melt. We image the crust and upper mantle discontinuity structure beneath the northern East African Rift System (EARS), a unique tectonically active continental rift exposing along strike the transition from continental rifting in the Main Ethiopian rift (MER) to incipient seafloor spreading in Afar and the Red Sea. S-to-P receiver functions from 182 stations across the northern EARS were generated from 3688 high quality waveforms using a multitaper technique and then migrated to depth using a regional velocity model. Waveform modelling of data stacked in large conversion point bins confirms the depth and strength of imaged discontinuities. We image the Moho at 29.6±4.7 km depth beneath the Ethiopian plateaux with a variability in depth that is possibly due to lower crustal intrusions. The crust is 27.3±3.9 km thick in the MER and thinner in northern Afar, 17.5±0.7 km. The model requires a 3±1.2% reduction in shear velocity with increasing depth at 68.5±1.5 km beneath the Ethiopian plateaux, consistent with the lithosphere-asthenosphere boundary (LAB). We do not resolve a LAB beneath Afar and the MER. This is likely associated with partial melt near the base of the lithosphere, reducing the velocity contrast between the melt-intruded lithosphere and the partially molten asthenosphere. We identify a 4.5±0.7% increase in velocity with depth at 91±3 km beneath the MER. This change in velocity is consistent with the onset of melting found by previous receiver functions and petrology studies. Our results provide independent constraints on the depth of melt production in the asthenosphere and suggest melt percolation through the base of the lithosphere beneath the northernmost East African rift.

  5. Planet Formation

    Science.gov (United States)

    Podolak, Morris

    2018-04-01

    Modern observational techniques are still not powerful enough to directly view planet formation, and so it is necessary to rely on theory. However, observations do give two important clues to the formation process. The first is that the most primitive form of material in interstellar space exists as a dilute gas. Some of this gas is unstable against gravitational collapse, and begins to contract. Because the angular momentum of the gas is not zero, it contracts along the spin axis, but remains extended in the plane perpendicular to that axis, so that a disk is formed. Viscous processes in the disk carry most of the mass into the center where a star eventually forms. In the process, almost as a by-product, a planetary system is formed as well. The second clue is the time required. Young stars are indeed observed to have gas disks, composed mostly of hydrogen and helium, surrounding them, and observations tell us that these disks dissipate after about 5 to 10 million years. If planets like Jupiter and Saturn, which are very rich in hydrogen and helium, are to form in such a disk, they must accrete their gas within 5 million years of the time of the formation of the disk. Any formation scenario one proposes must produce Jupiter in that time, although the terrestrial planets, which don't contain significant amounts of hydrogen and helium, could have taken longer to build. Modern estimates for the formation time of the Earth are of the order of 100 million years. To date there are two main candidate theories for producing Jupiter-like planets. The core accretion (CA) scenario supposes that any solid materials in the disk slowly coagulate into protoplanetary cores with progressively larger masses. If the core remains small enough it won't have a strong enough gravitational force to attract gas from the surrounding disk, and the result will be a terrestrial planet. If the core grows large enough (of the order of ten Earth masses), and the disk has not yet dissipated, then

  6. [Proceedings of the VII international symposium 'Cultural heritage in geosciences, mining and metallurgy : libraries, archives, museums' : "Museums and their collections" held at the Nationaal Natuurhistorisch Museum Leiden (The Netherlands), 19-23 May, 2003 / Cor F. Winkler Prins and Stephen K. Donovan (editors)]: Towards modern petrological collections

    NARCIS (Netherlands)

    Kriegsman, L.M.

    2004-01-01

    Petrological collections result from sampling for academic research, for aesthetic or commercial reasons, and to document natural diversity. Selection criteria for reducing and enhancing collections include adequate documentation, potential for future use, information density, time and money

  7. Galaxy Formation

    CERN Document Server

    Longair, Malcolm S

    2008-01-01

    This second edition of Galaxy Formation is an up-to-date text on astrophysical cosmology, expounding the structure of the classical cosmological models from a contemporary viewpoint. This forms the background to a detailed study of the origin of structure and galaxies in the Universe. The derivations of many of the most important results are derived by simple physical arguments which illuminate the results of more advanced treatments. A very wide range of observational data is brought to bear upon these problems, including the most recent results from WMAP, the Hubble Space Telescope, galaxy surveys like the Sloan Digital Sky Survey and the 2dF Galaxy Redshift Survey, studies of Type 1a supernovae, and many other observations.

  8. Galaxy formation

    International Nuclear Information System (INIS)

    Gribbin, J.

    1979-01-01

    The current debate on the origin and evolution of galaxies is reviewed and evidence to support the so-called 'isothermal' and 'adiabatic' fluctuation models considered. It is shown that new theories have to explain the formation of both spiral and elliptical galaxies and the reason for their differences. It is stated that of the most recent models the best indicates that rotating spiral galaxies are formed naturally when gas concentrates in the centre of a great halo and forms stars while ellipticals are explained by later interactions between spiral galaxies and merging, which can cancel out the rotation while producing an elliptical galaxy in which the stars, coming from two original galaxies, follow very elliptical, anisotropic orbits. (UK)

  9. Habit formation.

    Science.gov (United States)

    Smith, Kyle S; Graybiel, Ann M

    2016-03-01

    Habits, both good ones and bad ones, are pervasive in animal behavior. Important frameworks have been developed to understand habits through psychological and neurobiological studies. This work has given us a rich understanding of brain networks that promote habits, and has also helped us to understand what constitutes a habitual behavior as opposed to a behavior that is more flexible and prospective. Mounting evidence from studies using neural recording methods suggests that habit formation is not a simple process. We review this evidence and take the position that habits could be sculpted from multiple dissociable changes in neural activity. These changes occur across multiple brain regions and even within single brain regions. This strategy of classifying components of a habit based on different brain signals provides a potentially useful new way to conceive of disorders that involve overly fixed behaviors as arising from different potential dysfunctions within the brain's habit network.

  10. Habit formation

    Science.gov (United States)

    Smith, Kyle S.; Graybiel, Ann M.

    2016-01-01

    Habits, both good ones and bad ones, are pervasive in animal behavior. Important frameworks have been developed to understand habits through psychological and neurobiological studies. This work has given us a rich understanding of brain networks that promote habits, and has also helped us to understand what constitutes a habitual behavior as opposed to a behavior that is more flexible and prospective. Mounting evidence from studies using neural recording methods suggests that habit formation is not a simple process. We review this evidence and take the position that habits could be sculpted from multiple dissociable changes in neural activity. These changes occur across multiple brain regions and even within single brain regions. This strategy of classifying components of a habit based on different brain signals provides a potentially useful new way to conceive of disorders that involve overly fixed behaviors as arising from different potential dysfunctions within the brain's habit network. PMID:27069378

  11. MISR Views the Middle East

    Science.gov (United States)

    2000-01-01

    This image, generated using 16 orbits of MISR data collected between August 16 and August 30, 2000, takes us to the cradle of many civilizations. The data are from the 60-degree aftward-viewing camera. Because the individual orbit swaths are only 400 kilometers wide, they were 'mosaiced' together to form this composite picture, which covers about 2700 kilometers from west to east and 1750 kilometers from north to south. A few discontinuities are present in the mosaic, particularly near clouds, due to changes in the scene which occurred between dates when the individual orbit data were acquired.At the northern tip of the Red Sea, the Gulf of Suez and the Gulf of Aqaba frame the sandy deserts and spectacular mountains of the Sinai Peninsula. The highest peaks are Gebel Katherina (Mountain of St. Catherine, 2637 meters) and Gebel Musa (Mountain of Moses, also known as Mount Sinai, 2285 meters). To the northeast, Israel and Jordan flank the Dead Sea, one of the saltiest inland water bodies in the world. At its northern edge is Qumran, where the ancient Scrolls were discovered; the city of Jerusalem lies about 30 kilometers to the west.Several large rivers are prominent. Flowing southeastward through Iraq are the Tigris and Euphrates. The dark area between the two rivers, northwest of the Persian Gulf, is a very fertile region where fishing and farming are prevalent. Wending its way through eastern Egypt is the Nile. In the south is Lake Nasser and the Aswan Dam; continuing northward the Nile passes the Temple of Luxor as it sharply loops to the east. It then turns west and northward, eventually passing the capital city of Cairo, and finally spreading into a prominent delta as it empties into the Mediterranean Sea. The bright dot just west of the apex of the delta marks the location of the great Pyramids and Sphinx complexes on the Giza Plateau. On the coast, west of the delta, is the ancient city of Alexandria, Egypt's main seaport.'MISR', as it turns out, is the

  12. Networks model of the East Turkistan terrorism

    Science.gov (United States)

    Li, Ben-xian; Zhu, Jun-fang; Wang, Shun-guo

    2015-02-01

    The presence of the East Turkistan terrorist network in China can be traced back to the rebellions on the BAREN region in Xinjiang in April 1990. This article intends to research the East Turkistan networks in China and offer a panoramic view. The events, terrorists and their relationship are described using matrices. Then social network analysis is adopted to reveal the network type and the network structure characteristics. We also find the crucial terrorist leader. Ultimately, some results show that the East Turkistan network has big hub nodes and small shortest path, and that the network follows a pattern of small world network with hierarchical structure.

  13. A nuclear-weapon-free Middle East

    International Nuclear Information System (INIS)

    Jortner, Joshua

    1986-01-01

    The paper examines the issue of nuclear-weapon States involvement in regional conflicts, and whether such a conflict in the Middle East could trigger a nuclear war between the Super-Powers. Comments on the Middle Eastern situation are given, along with a discussion of the Non-Proliferation Treaty (NPT) and the Middle East, Israel and the NPT, and the nuclear potential in Arab countries. The proposal, by Israel, of a nuclear weapon-free zone in the Middle East is outlined. (UK)

  14. East Asian perspective on global environmental problems

    International Nuclear Information System (INIS)

    Yonehara, M.

    1995-01-01

    The Central Research Institute of Electric Power Industry has been conducting active global warming research programs focusing on development of a method to forecast climate change accompanying global warming both globally and in East Asia. A regional climate change forecasting method is being developed and researches are conducted on impacts of climate change on the natural and social environment in East Asia. Researches are also conducted focusing on the relationship between emissions and deposition of acid substances and assessment of the environmental impacts of acid rain in East Asia. 4 figs

  15. Petrological, geochemical and isotopic characteristics of lignite and calcified lignite from mining area Pesje, Velenje Basin, Slovenia

    Science.gov (United States)

    Vrabec, Mirijam; Markič, Miloš; Vrabec, Marko; Jaćimović, Radojko; Kanduč, Tjaša

    2014-05-01

    Lignite (organic rich) and calcified lignite (inorganic rich) samples from excavation field -50c mining area Pesje, Velenje Basin, Slovenia were investigated. During geological and structural mapping lignite and calcified lignite samples were systematically taken for determination of their petrological, geochemical and isotopic characteristics. Lignite is composed of fine detritical gelified matrix. At least five different types of calcified lignite were recognized forming laminations, calcifications after wood, petrified wood and complete replacements of lignite with carbonate. All measured parameters so far indicate geochemical processes during sedimentation of the Velenej Basin. After macroscopic description samples were split to organic and inorganic component (Ward, 1984) and powdered in an agate mortar for geochemical and isotopic analyses. Major and trace elements (As, B, Ba, Cd, Co, Cr, Cu, Hg, Mn, Mo, Sb, Se, Th, U, Zn) in these samples were determined by instrumental neutron activation analysis (INAA) using k-0 standardization method (Jaćimović et al, 2002). The isotopic composition of carbon and nitrogen was determined using a Europa 20-20 continuous flow IRMS ANCA-SL preparation module. A 1 mg amount of a sample was weighed in a tin capsule for carbon and 10 mg for nitrogen analysis. Samples for carbon analyses were pretreated with 1 M HCl to remove carbonates. Carbonate samples from carbonate-rich strata and calcified xylite were first roasted at 450 deg C (Krantz et al., 1987). Three miligrams of carbonate sample was transformed into CO2 by reaction with anhydrous H3PO4 at 55 deg C under vacuum (McCrea, 1950) and measured with GV 2003 isotope ratio mass spectrometer. Measured isotopic composition of oxygen as VPDB values was recalculated to the VSMOW reference standard to enable the comparison with data from other coal basins. SEM/EDXS of carbonate rich sediments was performed with JEOL JSM 5800 electron microanalyzer scanning electron microscope

  16. The oldest Mahonia (Berberidaceae) fossil from East Asia and its biogeographic implications.

    Science.gov (United States)

    Huang, Jian; Su, Tao; Lebereton-Anberrée, Julie; Zhang, Shi-Tao; Zhou, Zhe-Kun

    2016-03-01

    Interpretation of the biogeography of the genus Mahonia (Berberidaceae) is limited by the lack of fossil records in East Asia. Compressed fossil foliage, described here as Mahonia mioasiatica sp. nov., were collected from the Upper Miocene Xiaolongtan Formation in Wenshan, Yunnan, southwest China. These specimens represent the oldest reliable fossil record of Mahonia in East Asia. This new fossil species shows a general similarity to Group Orientales and is most similar to the extant eastern Asian Mahonia conferta. Considering other fossil evidence of Mahonia, we propose a migration route of this genus to Asia over the North Atlantic Land Bridge rather than the Bering Land Bridge. Our results also suggest that North America, Europe and East Asia have been successive centers of diversity for the genus, as a consequence of diversification in Group Orientales potentially related to historical climate change.

  17. Turkmenistan and the Middle East

    Directory of Open Access Journals (Sweden)

    Michael B. Bishku

    2016-01-01

    Full Text Available Turkmenistan is a weak country militarily, but well-­endowed with natural gas reserves. While the latter also insulates it somewhat from international criticism of its human rights abuses, unfortunately, Turkmenistan is landlocked and dependent upon the goodwill of its neighbors in order to export that commodity. Additionally, Turkmenistan is in need of technological assistance. Given its relatively homogenous population and its hydrocarbon wealth it has adopted a policy of subsidizing certain necessities—though it underfunds other—and is fairly stable internally. Nevertheless, it is ruled under an autocratic political system, suffers massive corruption, and has to contend with fears of instability on its borders. Therefore, Turkmenistan has adopted a policy of permanent neutrality and is open to cooperation with all its neighbors as well as the big powers. The countries of the Middle East as both immediate and nearby neighbors play an important part in the international relations of Turkmenistan and in providing technological assistance and economic investments. This article, which reviews and analyzes those ties, utilizes government documents, academic works and newspapers from Turkmenistan and Middle Eastern countries.

  18. Middle East food safety perspectives.

    Science.gov (United States)

    Idriss, Atef W; El-Habbab, Mohammad S

    2014-08-01

    Food safety and quality assurance are increasingly a major issue with the globalisation of agricultural trade, on the one hand, and intensification of agriculture, on the other. Consumer protection has become a priority in policy-making amongst the large economies of the Middle East and North Africa (MENA) countries following a number of food safety incidents. To enhance food safety, it is necessary to establish markets underpinned by knowledge and resources, including analysis of international rejections of food products from MENA countries, international laboratory accreditation, improved reporting systems and traceability, continued development and validation of analytical methods, and more work on correlating sensory evaluation with analytical results. MENA countries should develop a national strategy for food safety based on a holistic approach that extends from farm-to-fork and involves all the relevant stakeholders. Accordingly, food safety should be a regional programme, raising awareness among policy- and decision-makers of the importance of food safety and quality for consumer protection, food trade and economic development. © 2014 Society of Chemical Industry.

  19. Unrealistic Optimism: East and West?

    Science.gov (United States)

    Joshi, Mary Sissons; Carter, Wakefield

    2013-01-01

    Following Weinstein’s (1980) pioneering work many studies established that people have an optimistic bias concerning future life events. At first, the bulk of research was conducted using populations in North America and Northern Europe, the optimistic bias was thought of as universal, and little attention was paid to cultural context. However, construing unrealistic optimism as a form of self-enhancement, some researchers noted that it was far less common in East Asian cultures. The current study extends enquiry to a different non-Western culture. Two hundred and eighty seven middle aged and middle income participants (200 in India, 87 in England) rated 11 positive and 11 negative events in terms of the chances of each event occurring in “their own life,” and the chances of each event occurring in the lives of “people like them.” Comparative optimism was shown for bad events, with Indian participants showing higher levels of optimism than English participants. The position regarding comparative optimism for good events was more complex. In India those of higher socioeconomic status (SES) were optimistic, while those of lower SES were on average pessimistic. Overall, English participants showed neither optimism nor pessimism for good events. The results, whose clinical relevance is discussed, suggest that the expression of unrealistic optimism is shaped by an interplay of culture and socioeconomic circumstance. PMID:23407689

  20. Unrealistic optimism: east and west?

    Directory of Open Access Journals (Sweden)

    Mary Sissons Joshi

    2013-02-01

    Full Text Available Following Weinstein’s pioneering work (1980 many studies established that people have an optimistic bias concerning future life events. At first, the bulk of research was conducted using populations in North America and Northern Europe, the optimistic bias was thought of as universal, and little attention was paid to cultural context. However, construing unrealistic optimism as a form of self-enhancement, some researchers noted that it was far less common in East Asian cultures. The current study extends enquiry to a different non-Western culture. Two hundred and eighty seven middle aged and middle-income participants (200 in India, 87 in England rated 11 positive and 11 negative events in terms of the chances of each event occurring in their own life, and the chances of each event occurring in the lives of people like them. Comparative optimism was shown for bad events, with Indian participants showing higher levels of optimism than English participants. The position regarding comparative optimism for good events was more complex. In India those of higher socioeconomic status were optimistic, while those of lower socioeconomic status were on average pessimistic. Overall, English participants showed neither optimism nor pessimism for good events. The results, whose clinical relevance is discussed, suggest that the expression of unrealistic optimism is moulded by an interplay of culture and socioeconomic circumstance.

  1. Nature of the basement of the East Anatolian plateau: Implications for the lithospheric foundering processes

    Science.gov (United States)

    Topuz, G.; Candan, O.; Zack, T.; Yılmaz, A.

    2017-12-01

    The East Anatolian Plateau (Turkey) is characterized by (1) an extensive volcanic-sedimentary cover of Neogene to Quaternary age, (2) crustal thicknesses of 42-50 km, and (3) an extremely thinned lithospheric mantle. Its basement beneath the young cover is thought to consist of oceanic accretionary complexes of Late Cretaceous to Oligocene age. The attenuated state of the lithospheric mantle and the causes of the young volcanism are accounted for by slab steepening and subsequent break-off. We present field geological, petrological and geochronological data on three basement inliers (Taşlıçay, Akdağ and Ilıca) in the region. These areas are made up of amphibolite- to granulite-facies rocks, comprising marble, amphibolite, metapelite, quartzite and metagranite. The granulite-facies domain is equilibrated at 0.7 GPa and 800 ˚C at 83 ± 2 Ma (2σ). The metamorphic rocks are intruded by subduction-related coeval gabbroic, quartz monzonitic to tonalitic rocks. Both the metamorphic rocks and the intrusions are tectonically overlain by ophiolitic rocks. All these crystalline rocks are unconformably overlain by lower Maastrichtien clastic rocks and reefal limestone, suggesting that the exhumation at the earth's surface and juxtaposition with ophiolitic rocks occurred by early Maastrichtien. U-Pb dating on igneous zircon from metagranite yielded a protolith age of 445 ± 10 Ma (2σ). The detrital zircons from a metaquartzite point to Neoproterozoic to Early Paleozoic provenance. All these data favor a more or less continuous continental substrate to the allochthonous ophiolitic rocks beneath the young volcanic-sedimentary cover. The metamorphism and coeval magmatism can be regarded as the middle- to lower-crustal root of the Late Cretaceous magmatic arc that developed due to northward subduction along the Bitlis-Zagros suture. The presence of a continental basement beneath the young cover requires that the loss of the lithospheric mantle from beneath the East

  2. JPRS Report, Near East & South Asia

    National Research Council Canada - National Science Library

    1992-01-01

    This report covers international issues relating to the Near East: regional affairs, Palestinian affairs, Iraq, Jordan, Mauritania, Morocco, Sudan, United Arab Emirates, and the Republic of Yemen; and South Asia...

  3. Scopus: Journal of East African Ornithology: Contact

    African Journals Online (AJOL)

    Principal Contact. Darcy Ogada Dr Bird Committee of the East Africa Natural History Society. Editors,. Scopus,. c/o Nature Kenya,. P.O. Box 44486,. G.P.O. 00100,. Nairobi, Kenya. Email: scopus@naturekenya.org ...

  4. East African Journal of Sciences: Submissions

    African Journals Online (AJOL)

    Aims The East African Journal of Sciences (EAJS) publishes original scientific ... of ideas among scientists engaged in research and development activities; and ... font size 12, Times New Roman), including tables, figures and illustrations.

  5. Near East/South Asia Report

    National Research Council Canada - National Science Library

    1986-01-01

    .... This report from the Near East/South Asia, Egypt, Libya, Tunisa, Iraq, Israel, Kuwait, Oman, Saudi Arabia, Syria, United Arab Emirates, Iran and Pakistan, the articles are on Politics, Economics...

  6. Zoning, 2004, East Baton Rouge Parish, Louisiana

    Data.gov (United States)

    Louisiana Geographic Information Center — This is a graphical polygon dataset depicting the zoning boundaries of the East Baton Rouge Parish of the State of Louisiana. Zoning can be defined as the range of...

  7. Scientific Communication | Okolo | East African Medical Journal

    African Journals Online (AJOL)

    East African Medical Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 92, No 2 (2015) >. Log in or Register to get access to full text downloads.

  8. Biogas - Bioenergy potential in East Africa

    International Nuclear Information System (INIS)

    1997-01-01

    The workshop is part of the project: 'Energy production from Sisal Waste in East Africa' sponsored by the Danish Energy Agency, an agency under the Danish Ministry of Environment and Energy. This project has been carried out in close cooperation between the Danish Technological Institute and University of Dar es Salaam, Applied Microbiology Unit, who has also taken care of the practical arrangement. The main objectives of the workshop was: To present the ongoing research in East Africa on biogas production from organic residues; To get an overview of political and administrative issues related to promotion and implementation of renewable energy facilities in East Africa; To discuss appropriate set-ups for bioenergy facilities in East Africa. (au)

  9. Biogas - Bioenergy potential in East Africa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-31

    The workshop is part of the project: `Energy production from Sisal Waste in East Africa` sponsored by the Danish Energy Agency, an agency under the Danish Ministry of Environment and Energy. This project has been carried out in close cooperation between the Danish Technological Institute and University of Dar es Salaam, Applied Microbiology Unit, who has also taken care of the practical arrangement. The main objectives of the workshop was: To present the ongoing research in East Africa on biogas production from organic residues; To get an overview of political and administrative issues related to promotion and implementation of renewable energy facilities in East Africa; To discuss appropriate set-ups for bioenergy facilities in East Africa. (au)

  10. Biogas - Bioenergy potential in East Africa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    The workshop is part of the project: `Energy production from Sisal Waste in East Africa` sponsored by the Danish Energy Agency, an agency under the Danish Ministry of Environment and Energy. This project has been carried out in close cooperation between the Danish Technological Institute and University of Dar es Salaam, Applied Microbiology Unit, who has also taken care of the practical arrangement. The main objectives of the workshop was: To present the ongoing research in East Africa on biogas production from organic residues; To get an overview of political and administrative issues related to promotion and implementation of renewable energy facilities in East Africa; To discuss appropriate set-ups for bioenergy facilities in East Africa. (au)

  11. Hydrography, 2004, East Baton Rouge Parish, Louisiana

    Data.gov (United States)

    Louisiana Geographic Information Center — The Hydrography layer is an area geometry depicting the various water features that include the rivers, streams, creeks, lakes, etc of East Baton Rouge Parish.

  12. The Water Conflict in the Middle East

    National Research Council Canada - National Science Library

    1997-01-01

    The water conflict in the Middle East is reaching a crisis peak. The region suffers from a shortage of water, a high rate of population growth and the absence of a clear criteria for sharing waters within the region...

  13. Near East/South Asia Report

    National Research Council Canada - National Science Library

    1986-01-01

    .... This report from the Near East/South Asia, Algeria, Egypt, Sudan, Tunisia, Israel, Lebanon, Afghanistan, Bangladesh, Iran and Pakistan, contains articles on Politics, Economics, Regional Affairs and Military Affairs...

  14. EAST OJAI HYDROLOGY, VENTURA COUNTY, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — The basis of the hydrologic data for East Ojai FIS is the HSPF study for Ventura River watershed documented in a report entitled...

  15. East African Agricultural and Forestry Journal

    African Journals Online (AJOL)

    East African Agricultural and Forestry Journal is published by the Kenya ... water resource base to meet the challenges of poverty alleviation and food security. ... on maize growth, nitrogen uptake and yield in a semi-arid Kenyan environment ...

  16. Lunar Science Conference, 4th, Houston, Tex., March 5-8, 1973, Proceedings. Volume 1 - Mineralogy and petrology. Volume 2 - Chemical and isotope analyses. Organic chemistry. Volume 3 - Physical properties

    Science.gov (United States)

    Gose, W. A.

    1973-01-01

    The mineralogy, petrology, chemistry, isotopic composition, and physical properties of lunar materials are described in papers detailing methods, results, and implications of research on samples returned from eight lunar landing sites: Apollo 11, 12, 14, 15, 16, 17, and Luna 16 and 20. The results of experiments conducted or set up on the lunar surface by the astronauts are also described along with observations taken from Command Modules and subsatellites. Major topics include general geology, soil and breccia studies, petrologic studies, mineralogic analyses, elemental compositions, radiometric age determinations, rare gas chemistry, radionuclides, organogenic compounds, particle track records, thermal properties, seismic studies, resonance studies, orbital mapping, lunar atmosphere, magnetic studies, electrical studies, optical properties, and microcratering. Individual items are announced in this issue.

  17. ISSN 2073-9990 East Cent. Afr. J. 0 East Cent. Afr. J. 0 East Cent ...

    African Journals Online (AJOL)

    dell

    2014-04-01

    Apr 1, 2014 ... Ewing's sarcoma. For diagnostic purposes, conventional radiography usually provides adequate information. The findings of bone destruction associated with sclerotic foci of tumour bone formation, an aggressive (sunburst-type, lamellated, or Codman triangle) periosteal reaction, and a soft tissue mass are ...

  18. Microbial keratitis in West and East Malaysia

    OpenAIRE

    Vanitha Ratnalingam; Thiageswari Umapathy; Kala Sumugam; Hanida Hanafi; Shamala Retnasabapathy

    2017-01-01

    AIM: To evaluate the epidemiological and etiological factors of microbial keratitis seen in tertiary hospitals in West and East Malaysia.METHODS: A total of 207 patients were enrolled. Patients referred for microbial keratitis to Sungai Buloh Hospital and Kuala Lumpur Hospital in West Malaysia and Queen Elizabeth Hospital and Kuching General Hospital in East Malaysia were recruited. Risk factors were documented. Corneal scrapings for microscopy and culture were performed.RESULTS: The most com...

  19. Regional Integration: A Political Federation of the East African ...

    African Journals Online (AJOL)

    The aim of this paper is to explore the possibility and viability of an East African political federation project. Since the late 1800s under the then British East Africa, the countries of East Africa have been searching for ways to integrate. The search led to the establishment of the East African Community (EAC) in December ...

  20. Mechanisms of formation damage in matrix-permeability geothermal wells

    Energy Technology Data Exchange (ETDEWEB)

    Bergosh, J.L.; Wiggins, R.B.; Enniss, D.O.

    1982-04-01

    Tests were conducted to determine mechanisms of formation damage that can occur in matrix permeability geothermal wells. Two types of cores were used in the testing, actual cores from the East Mesa Well 78-30RD and cores from a fairly uniform generic sandstone formation. Three different types of tests were run. The East Mesa cores were used in the testing of the sensitivity of core to filtrate chemistry. The tests began with the cores exposed to simulated East Mesa brine and then different filtrates were introduced and the effects of the fluid contrast on core permeability were measured. The East Mesa cores were also used in the second series of tests which tested formation sandstone cores were used in the third test series which investigated the effects of different sizes of entrained particles in the fluid. Tests were run with both single-particle sizes and distributions of particle mixes. In addition to the testing, core preparation techniques for simulating fracture permeability were evaluated. Three different fracture formation mechanisms were identified and compared. Measurement techniques for measuring fracture size and permeability were also developed.

  1. Human Capital Formation in the Gulf and MENA Region.

    Science.gov (United States)

    Shaw, Ken E.

    2001-01-01

    Recent developments in human capital formation theories are particularly relevant to the Gulf and Middle Eastern and North African regions. Discusses recent western reconfigurations of the theory, noting how much local work must be done to reshape theory appropriately in the Middle East and explaining how issues relating to employment, education,…

  2. Petrology of the Fort Smith - Great Slave Lake radiometric high near Pilot Lake, N.W.T

    International Nuclear Information System (INIS)

    Burwash, R.A.; Cape, D.F.

    1981-01-01

    Near Pilot Lake, the east boundary of the Fort Smith - Great Slave Lake radiometric high coincides with the contact of a well-foliated, porphyroblastic microcline-plagioclase-quartz-garnet-biotite gneiss (Pilot Lake Gneiss) with a hybrid assemblage of quartzite, mica schist, garnet-cordierite gneiss, and minor amphibolite (Variable Paragneiss). Anomalously high concentrations of uranium and thorium are associated with mafic-rich, lenticular bodies with a mineral assemblage biotite + monazite + zircon + ilmenite + hematite +- plagioclase +- quartz, within both the Variable Paragneiss and the Pilot Lake Gneiss. Corundum and spinel occur in the mafic lenses and sillimanite, kyanite, and hypersthene in other inclusions of the Pilot Lake Gneiss. The ilmenite-magnetite--monazite-zircon-apatite assemblage is interpreted as a 'black sand' concentration in a clastic sedimentary sequence subsequently metamorphosed by a regional granulite facies event. A granite pluton intruded during the same orogenic cycle assimilated the clastic metasedimentary rocks containing black sand interlayers, becoming enriched in thorium from the monazite. A second metamorphic event at lower P-T conditions, accompanied by strong cataclasis, developed the texture of the Pilot Lake Gneiss as now observed. Shearing within the gneiss locally concentrated hematite + quartz + uranium. Regional tectonic extrapolations suggest that the pyroxene granulite event was Kenoran and the later amphibolite event Hudsonian. (author)

  3. Overview of EAST progress and near future plan

    International Nuclear Information System (INIS)

    Gong, X.; Li, J.; Wan, B.N.; Qian, J.P.; Cao, L.

    2015-01-01

    Full text of publication follows. The Experimental Advanced Superconducting Tokamak (EAST) is a fully superconducting tokamak with a flexible poloidal field system to accommodate both single null (SN) and double null (DN) divertor configurations, and its main mission is to establish steady-state high performance plasma and study related physics and technologies. Significant progress has recently been made on EAST with the following key issues. Developments of PFMs and improvements of the actively water-cooled PFCs and other in-vessel components, such as VS coils and diagnostics, have been carried out in the past few years to have the highest priority suitable for long pulse operation. Large pumping capacity (inner cryo-pump) and a new CW Pellet Injection system and Supersonic Molecule Beam Injection (SMBI) system to enhance fueling efficiency for particle control have been validated. ICRH and LHCD systems have been upgraded to a total power of 8 MW. Integrated operation scenarios (plasma startup, and ramp up/down) with advanced Plasma Control are focused on superconducting tokamak to avoid the huge thermal energy impact on the first wall. With these newly augmented capabilities, EAST have demonstrated long pulse divertor plasma up to 411 s, fully driven by LHCD of 1.0 MW, and further extended long pulse H-modes over 30 s with LHCD and ICRH, much longer than several tens of the current diffusion time. When LHCD is applied to the H-mode plasmas with ICRH, strong mitigation of ELMs has been observed due to the formation of Helical Current Filaments (HCFs) flowing along field lines in the SOL induced by LHCD. Highly efficient ELM pacing is demonstrated by using innovative Li pellet injection. ELMs mitigation with multi-pulse of SMBI also has been demonstrated in EAST in quasi-steady state over current diffusion time. Several experiments have addressed the importance of zonal flow and zonal flow-driven limit-cycle oscillations in H-mode physics. A new small-ELM regime

  4. R and D on passive stabilization loop at EAST

    Energy Technology Data Exchange (ETDEWEB)

    Ji, X., E-mail: jixiang@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, Anhui 230031 (China); Song, Y.T.; Wu, S.T.; Shen, G.; Wang, Z.; Cao, L.; Zhou, Z.; Liu, X.; Peng, X.; Wang, C.; Wang, S.; Zhu, N.; Zhang, P.; Wu, J.; Gong, X.; Shen, B.; Gao, D.; Fu, P.; Wan, B.; Li, J. [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, Anhui 230031 (China)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer The passive stabilization loop (PSL) is part of the plasma stabilization system built in the EAST. The project of PSL has been carried out. Black-Right-Pointing-Pointer The EM and structural analysis of PSL has been done. Black-Right-Pointing-Pointer The R and D of the silvered craft for the PSL is done. Black-Right-Pointing-Pointer The R and D of the insulation structure for the PSL is done. - Abstract: The passive stabilization loop (PSL) is part of the plasma stabilization system built in the EAST. Its purpose is to provide passive feedback control of the plasma vertical instability on short time scales. To accommodate with the new stage for high performance plasma and enhance the control of vertical stabilization in EAST, the project of PSL has been carried out. The eddy currents are induced by the vertical displacement events (VDEs) and disruption. The distribution of the eddy currents depend on the structure of the PSL and the formation of the induction. The global model is created and meshed by the ANSYS software. Based on the simulation of plasma VDEs and disruption, the distribution and decay curve of the eddy currents on the PSL are obtained. The stress and the strain caused by the eddy currents and the magnetic field are calculated. To decrease the resistance of the joint and enhance anti-corrosion of the joint surface, the silvered craft is used. In the experiment of test model, the resistance is decreased to half after silvered with the same matrix material and under the same preload. The PSL is insulated from the vacuum vessel at the supports of passive stabilizers. The insulation structure is designed and tested with ceramic material. The PSL is designed, fabricated and assembled with the total resistance 150 {mu}{Omega}. It can supply passive feedback control to the plasma by the eddy currents induced by the VDEs, which could enhance the vertical placement control of plasma.

  5. R and D on passive stabilization loop at EAST

    International Nuclear Information System (INIS)

    Ji, X.; Song, Y.T.; Wu, S.T.; Shen, G.; Wang, Z.; Cao, L.; Zhou, Z.; Liu, X.; Peng, X.; Wang, C.; Wang, S.; Zhu, N.; Zhang, P.; Wu, J.; Gong, X.; Shen, B.; Gao, D.; Fu, P.; Wan, B.; Li, J.

    2012-01-01

    Highlights: ► The passive stabilization loop (PSL) is part of the plasma stabilization system built in the EAST. The project of PSL has been carried out. ► The EM and structural analysis of PSL has been done. ► The R and D of the silvered craft for the PSL is done. ► The R and D of the insulation structure for the PSL is done. - Abstract: The passive stabilization loop (PSL) is part of the plasma stabilization system built in the EAST. Its purpose is to provide passive feedback control of the plasma vertical instability on short time scales. To accommodate with the new stage for high performance plasma and enhance the control of vertical stabilization in EAST, the project of PSL has been carried out. The eddy currents are induced by the vertical displacement events (VDEs) and disruption. The distribution of the eddy currents depend on the structure of the PSL and the formation of the induction. The global model is created and meshed by the ANSYS software. Based on the simulation of plasma VDEs and disruption, the distribution and decay curve of the eddy currents on the PSL are obtained. The stress and the strain caused by the eddy currents and the magnetic field are calculated. To decrease the resistance of the joint and enhance anti-corrosion of the joint surface, the silvered craft is used. In the experiment of test model, the resistance is decreased to half after silvered with the same matrix material and under the same preload. The PSL is insulated from the vacuum vessel at the supports of passive stabilizers. The insulation structure is designed and tested with ceramic material. The PSL is designed, fabricated and assembled with the total resistance 150 μΩ. It can supply passive feedback control to the plasma by the eddy currents induced by the VDEs, which could enhance the vertical placement control of plasma.

  6. RUSSIA'S PARTICIPATION IN MULTILATERAL MECHANISMS IN EAST ASIA

    Directory of Open Access Journals (Sweden)

    Natalya V. Stapran

    2014-01-01

    Full Text Available After the end of the Cold War Russia has significantly increased its participation in multilateral mechanisms in the Asia-Pacific region and is clearly trying to become a significant player in regional institution-building. For two post-Cold War Russia decades was involved in almost all the basic mechanisms of multilateral cooperation in the Asia-Pacific region. However, often Russia isn't perceived by Asian partners as an equal participant in the Asia-Pacific region, it is felt particularly in the area of multilateral economic cooperation. Russia's entry into the WTO (2011 and the formation of the Common Economic stimulated Russia's engagement in multilateral economic structures. Russia's inclusion in the negotiating framework of ASEM (2010 and EAS (2011 perceives that Asian countries are willing to see Russia as a full member not only in regional processes, but also globally. The main stimulus for the revision of the Asian direction of foreign policy and the role of Siberia and the Far East appears during APEC summit in Vladivostok in 2012. The APEC summit demonstrated the geostrategic importance of the development of the Russian Far East and Siberia, as a key element of Russia's inclusion in the mechanisms of regional cooperation, on the other hand, it became clear that without the participation of foreign partners effective development of the Far Eastern territories is hardly possible. Large-scale investment and infrastructure projects in the Far East has already significantly revived the situation in the region opening new opportunities for multilateral cooperation.

  7. Russia's Participation In Multilateral Mechanisms In East Asia

    Directory of Open Access Journals (Sweden)

    Natalya V. Stapran

    2014-01-01

    Full Text Available After the end of the Cold War Russia has significantly increased its participation in multilateral mechanisms in the Asia-Pacific region and is clearly trying to become a significant player in regional institution-building. For two post-Cold War Russia decades was involved in almost all the basic mechanisms of multilateral cooperation in the Asia-Pacific region. However, often Russia isn't perceived by Asian partners as an equal participant in the Asia-Pacific region, it is felt particularly in the area of multilateral economic cooperation. Russia's entry into the WTO (2011 and the formation of the Common Economic stimulated Russia's engagement in multilateral economic structures. Russia's inclusion in the negotiating framework of ASEM (2010 and EAS (2011 perceives that Asian countries are willing to see Russia as a full member not only in regional processes, but also globally. The main stimulus for the revision of the Asian direction of foreign policy and the role of Siberia and the Far East appears during APEC summit in Vladivostok in 2012. The APEC summit demonstrated the geostrategic importance of the development of the Russian Far East and Siberia, as a key element of Russia's inclusion in the mechanisms of regional cooperation, on the other hand, it became clear that without the participation of foreign partners effective development of the Far Eastern territories is hardly possible. Large-scale investment and infrastructure projects in the Far East has already significantly revived the situation in the region opening new opportunities for multilateral cooperation.

  8. A new approach to the unrest and subsequent eruption at El Hierro Island (2011) based on petrological, seismological, geodetical and gravimetric data

    Science.gov (United States)

    Meletlidis, Stavros; Di Roberto, Alessio; Domínguez Cerdeña, Itahiza; Pompilio, Massimo; García-Cañada, Laura; Bertagnini, Antonella; Benito Saz, Maria Angeles; Del Carlo, Paola; Sainz-Maza Aparicio, Sergio; Lopez Moreno, Carmen; Moure García, David

    2014-05-01

    A shallow submarine eruption took place on 10th October 2011, about 1.8 km off the coast of La Restinga, a small village located in El Hierro (Canary Islands, Spain). The eruption lasted for about four months and ended by early March 2012. The eruption was preceded by an unrest episode that initiated about three months before, in July 2011, and characterized by more than 10,000 localized earthquakes accompanied by up to 5 cm of vertical ground deformation. In the Canary Islands, this event represents the first case of an eruption that was monitored since the unrest to the end by the monitoring network of IGN (Instituto Geográfico National), providing a huge dataset that includes geophysical (seismic, magnetic and gravimetric), geodetic, geochemistry and petrological data. In this work we use the seismic, GPS and gravity records collected by IGN along with the petrological data derived from the study of various lava balloons, scoriaceous fragments and ash.Geophysical and geochemical monitoring tools provide a variety of information that need to be interpreted in terms of magma movement and/or interaction of magma with host rocks. We present a model, based on this data, which describes the intrusion and ascent of the magma. According to this model, a major intrusion beneath and around preexisting high-density magmatic bodies, localized in the central sector of the island, led to an eruption in the Southern sector of the island. After a failed attempt to reach the surface, while various dykes were emplaced, through a low fractured area in the Central and Northern parts of the island, the ascending magma finally found its way in the submarine area of La Restinga, in the South rift zone, at a depth of 350 m below sea level. Feeding of the eruption was achieved by the ascension of an important volume of material from the upper mantle which was emplaced near the crust-mantle boundary. However, the very energetic post-eruptive unrests - we had five episodes up today with

  9. Field-trip guide to Mount St. Helens, Washington - An overview of the eruptive history and petrology, tephra deposits, 1980 pyroclastic density current deposits, and the crater

    Science.gov (United States)

    Pallister, John S.; Clynne, Michael A.; Wright, Heather M.; Van Eaton, Alexa R.; Vallance, James W.; Sherrod, David R.; Kokelaar, B. Peter

    2017-08-02

    This field trip will provide an introduction to several fascinating features of Mount St. Helens. The trip begins with a rigorous hike of about 15 km from the Johnston Ridge Observatory (9 km north-northeast of the crater vent), across the 1980 Pumice Plain, to Windy Ridge (3.6 km northeast of the crater vent) to examine features that document the dynamics and progressive emplacement of pyroclastic flows. The next day, we examine classic tephra outcrops of the past 3,900 years and observe changes in thickness and character of these deposits as we traverse their respective lobes. We examine clasts in the deposits and discuss how the petrology and geochemistry of Mount St. Helens deposits reveal the evolution of the magmatic system through time. We also investigate the stratigraphy of the 1980 blast deposit and review the chronology of this iconic eruption as we travel through the remains of the blown-down forest. The third day is another rigorous hike, about 13 km round trip, climbing from the base of Windy Ridge (elevation 1,240 m) to the front of the Crater Glacier (elevation 1,700 m). En route we examine basaltic andesite and basalt lava flows emplaced between 1,800 and 1,700 years before present, a heterolithologic flow deposit produced as the 1980 blast and debris avalanche interacted, debris-avalanche hummocks that are stranded on the north flank and in the crater mouth, and shattered dacite lava domes that were emplaced between 3,900 and 2,600 years before present. These domes underlie the northern part of the volcano. In addition, within the crater we traverse well-preserved pyroclastic-flow deposits that were emplaced on the crater floor during the summer of 1980, and a beautiful natural section through the 1980 deposits in the upper canyon of the Loowit River.Before plunging into the field-trip log, we provide an overview of Mount St. Helens geology, geochemistry, petrology, and volcanology as background. The volcano has been referred to as a

  10. Sequence stratigraphy, organic petrology and chemistry applied to the upper and lower coal seams in the Candiota Coalfield, Parana Basin, RS, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, J.S. de; Kalkreuth, W. [Instituto de Geociencias, UFRGS, Porto Alegre (Brazil)

    2010-12-01

    The Permian age coal seams in the Candiota Coalfield represent the largest coal deposit of the country. Currently two seams are mined, called ''Camada Candiota Superior'' and ''Camada Candiota Inferior''. The other coal seams of the coalfield, seams S1-S9 (upper seams) and I1-I5 (lower seams) have as yet not been exploited. The objective of this paper is to perform a detailed sequence stratigraphic, petrologic and chemical study of the upper and lower coal seams, thereby generating data for assisting in the development and better use of the coal-bearing interval. The methodology includes application of the concepts of sequence stratigraphy, which includes the lithological interpretation of the core to establish the depositional environments and genetic correlation between facies associations to define parasequences and bounding surfaces; coal petrology (analysis of the reflectance of vitrinite, determination of the petrographic composition of the coals by maceral analyses), and chemical analyses such as sulphur determination, proximate analyses (ash, moisture, volatile matter, and fixed carbon), and elemental analyses. Three main depositional systems were so far identified: alluvial fan, fluvial system, lagoonal estuary system. This study shows that coal development was controlled by accommodation/accumulation rates, with coal seams with greater thickness and lateral continuity being formed within the transgressive systems tract (lagoonal depositional system) of parasequence 2 (PS2), indicating that the accumulation rates of the peat and distribution of the coal seams were controlled by stratigraphic setting. Vitrinite reflectances for the upper and lower coal seams are indicative of subbituminous rank (Rrandom = 0.36-0.47%), with evidence that anomalously low reflectance values are related to high mineral-matter contents. Maceral composition is highly variable, with some coal seams being extremely rich in inertinite (up to

  11. Channel flow and localized fault bounded slice tectonics (LFBST): Insights from petrological, structural, geochronological and geospeedometric studies in the Sikkim Himalaya, NE India

    Science.gov (United States)

    Chakraborty, Sumit; Mukhopadhyay, Dilip K.; Chowdhury, Priyadarshi; Rubatto, Daniela; Anczkiewicz, Robert; Trepmann, Claudia; Gaidies, Fred; Sorcar, Nilanjana; Dasgupta, Somnath

    2017-06-01

    One of the enduring debates in the study of the Himalayan orogen (and continental collision zones in general) is whether the salient observed features are explained (a) by localized deformation along discrete, narrow fault zones/ductile shear zones separating individual blocks or slices (e.g. critical taper or wedge tectonic models), or (b) by distributed deformation dominated by wide zones of visco-plastic flow in the solid or a partially molten state (e.g. channel flow models). A balanced cross-section from Sikkim in the eastern Himalaya that is based on structural data and is drawn to satisfy petrological and geophysical constraints as well, is used in combination with information from petrology, geochronology, geospeedometry and microstructural data to address this question. We discuss that any tectonic model needs to be thermally, rheologically, geometrically and temporally viable in order to qualify as a suitable description of a system; models such as channel flow and critical taper are considered in this context. It is shown that channel flow models may operate with or without an erosional porthole (channel with tunnel and funnel mode vs. channels with only the tunnel mode) and that the predicted features differ significantly between the two. Subsequently, we consider a large body of data from Sikkim to show that a channel flow type model (in the tunneling without funneling mode), such as the ones of Faccenda et al. (2008), describes features formed at high temperatures very well, while features formed at lower temperatures are more consistent with the operation of localized, fault-bounded, slice tectonics, (LFBST, be it in the form of critical taper, wedge tectonics, or something else). Thus, the two modes are not competing, but collaborating, processes and both affect a given rock unit at different points of time during burial, metamorphism and exhumation. A transitional stage separates the two end-member styles of tectonic evolution. The proposed models

  12. Invasion of Hydrous Fluids Predates Kimberlite Formation

    Science.gov (United States)

    Kopylova, M. G.; Wang, Q.; Smith, E. M.

    2017-12-01

    Petrological observations on diamonds and peridotite xenoliths in kimberlites point towards an influx of hydrous metasomatic fluids shortly predating kimberlite formation. Diamonds may grow at different times within the same segment of the cratonic mantle, and diamonds that form shortly before (diamonds typically contain 10-25 wt.% water in fluid inclusions, while older octahedrally-grown diamonds host "dry" N2-CO2 fluids. Our recent studies of fluids in diamond now show that many different kinds of diamonds can contain fluid inclusions. Specifically, we found a new way to observe and analyze fluids in octahedrally-grown, non-fibrous diamonds by examining healed fractures. This is a new textural context for fluid inclusions that reveals a valuable physical record of infiltrating mantle fluids, that postdate diamond growth, but equilibrate within the diamond stability field at depths beyond 150 km. Another sign of the aqueous fluids influx is the formation of distinct peridotite textures shortly predating the kimberlite. Kimberlites entrain peridotite xenoliths with several types of textures: older coarse metamorphic textures and younger, sheared textures. The preserved contrast in grain sizes between porphyroclasts and neoblasts in sheared peridotites constrain the maximum duration of annealing. Experimental estimates of the annealing time vary from 7x107 sec (2 years) to 106 years (1 My) depending on olivine hydration, strain rate, pressure, temperature and, ultimately, the annealing mechanism. Kimberlite sampling of sheared peridotites from the lithosphere- asthenosphere boundary (LAB) implies their formation no earlier than 1 My prior to the kimberlite ascent. Water contents of olivine measured by FTIR spectrometry using polarized light demonstrated contrasting hydration of coarse and sheared samples. Olivine from sheared peridotite samples has the average water content of 78±3 ppm, in contrast to the less hydrated coarse peridotites (33±6 ppm). LAB hydration

  13. Petrology and geochemistry of volcanic rocks of Cheshmeh Khuri and Shekasteh Sabz areas, Khur, northwest of Birjand

    Directory of Open Access Journals (Sweden)

    Maryam Javidi Moghaddam

    2016-09-01

    Full Text Available Khur area is located in east of Iran and northwest of Birjand. The area comprises outcrops of Eocene to Oligocene volcanics with basaltic andesite to rhyolite composition, which were intruded by subvolcanic and intrusive bodies of granodiorite to gabbro. In the present work, petrogenesis of volcanic units in Cheshmeh Khuri and Shekasteh Sabz areas was studied, which are located in Khur area and these volcanics have most widespread in them. Rhyolite, dacite, andesite, trachyandesite and basaltic andesite units in Cheshmeh Khuri and trachyandesite unit in Shekasteh Sabz were identified. The main textures of these units are porphyritic, hialoporphyritic and microlitic and plagioclase, pyroxene, K-feldspar, hornblende, biotite and quartz are the main minerals. Volcanic units of Cheshmeh Khuri have characteristic of high-K Calc-alkaline. Enrichment of LREE relative to HREE and LILE to HFSE are important evidences that magma was formed in a magmatic belt of a subduction zone. Based on the initial 87Sr/86Sr of andesite and dacite, their magma has originated from partial melting of an enriched mantle and contaminated with the crust through its differentiation. Trachyandesites of Shekaste Sabz have characteristic of shoshonitic nature. These units are characterized by high FeOt/FeOt+MgO, K2O/Na2O and Zr>360 ppm, Y>39 ppm, and Ce> 100 ppm. Also, they are enrichment in REE particularly in LREE, depletion of Eu, strong enrichment in HFSE, and depletion in Ba and Sr. Therefore, trachyandesites of Shekaste Sabz belong to post collision volcanics.

  14. The great East Japan earthquake

    Energy Technology Data Exchange (ETDEWEB)

    Fluke, R.

    2011-06-15

    'Full text:' More formally called the Tohoku-Chihou-Taiheiyo-Oki Earthquake of March 11, 2011, it was the ensuing tsunami that caused the most death and destruction to the north-east coastal region of Japan. It is also what caused the multiple meltdowns at Fukushima Dai-ichi. Reactor Unit 1, ironically, was scheduled to be permanently shut down for decommissioning just two weeks later. The Fukushima Dai-ichi nuclear power plant has a tsunami protection barrier designed for the worst recorded tsunami in that area since 1896 - to a height of 5.7 m. The plant itself is on an elevated grade of about 10 m. The tsunami, reported to be 14-15 m, caused inundation of the entire site with at least four metres of seawater. The seawater flooded the turbine building and damaged electrical equipment including the emergency diesel generators, leaving the entire six-unit nuclear power plan without any source of AC power, known as the 'station blackout scenario'. There are numerous reports available on-line at various sites. The Japanese Government report is frank and forthcoming on the causes and the lessons learned, and the lAEA Mission report is in-depth and well presented, not only as a factual account of the events but as a unified source of the conclusions and lessons learned. Photos of the catastrophe are available at the TEPCO web site: http://www.tepco.co.jp/en/index-e.html. In this edition of the Bulletin there is a 'layman's' description of CANDU and BWR design in terms of the fundamental safety principles - Control, Cool and Contain as well as a description of how these principles were met, or not met at Fukushima Dai-ichi. Also, an excerpt from the IAEA Expert Mission is included. We 'technocrats' sometimes forget about the human aspects of a nuclear disaster. An essay by Dr. Michael Edwards is included entitled 'Psychology, Philosophy and Nuclear Science'. Other references to the events appear throughout this

  15. The great East Japan earthquake

    International Nuclear Information System (INIS)

    Fluke, R.

    2011-01-01

    'Full text:' More formally called the Tohoku-Chihou-Taiheiyo-Oki Earthquake of March 11, 2011, it was the ensuing tsunami that caused the most death and destruction to the north-east coastal region of Japan. It is also what caused the multiple meltdowns at Fukushima Dai-ichi. Reactor Unit 1, ironically, was scheduled to be permanently shut down for decommissioning just two weeks later. The Fukushima Dai-ichi nuclear power plant has a tsunami protection barrier designed for the worst recorded tsunami in that area since 1896 - to a height of 5.7 m. The plant itself is on an elevated grade of about 10 m. The tsunami, reported to be 14-15 m, caused inundation of the entire site with at least four metres of seawater. The seawater flooded the turbine building and damaged electrical equipment including the emergency diesel generators, leaving the entire six-unit nuclear power plan without any source of AC power, known as the 'station blackout scenario'. There are numerous reports available on-line at various sites. The Japanese Government report is frank and forthcoming on the causes and the lessons learned, and the lAEA Mission report is in-depth and well presented, not only as a factual account of the events but as a unified source of the conclusions and lessons learned. Photos of the catastrophe are available at the TEPCO web site: http://www.tepco.co.jp/en/index-e.html. In this edition of the Bulletin there is a 'layman's' description of CANDU and BWR design in terms of the fundamental safety principles - Control, Cool and Contain as well as a description of how these principles were met, or not met at Fukushima Dai-ichi. Also, an excerpt from the IAEA Expert Mission is included. We 'technocrats' sometimes forget about the human aspects of a nuclear disaster. An essay by Dr. Michael Edwards is included entitled 'Psychology, Philosophy and Nuclear Science'. Other references to the events appear throughout this edition.(author)

  16. A coastal hazards data base for the US East Coast

    Energy Technology Data Exchange (ETDEWEB)

    Gornitz, V.M. [National Aeronautics and Space Administration, New York, NY (United States). Goddard Inst. for Space Studies; White, T.W. [Oak Ridge National Lab., TN (United States); Daniels, R.C. [Energy, Environment and Resources Center, University of Tennessee, Knoxville, TN (United States)

    1992-08-01

    This document describes the contents of a digital data base that may be used by raster or vector geographic information systems (GIS) and non-GIS data bases to assess the risk of coastlines to erosion or sea level rise. The data base integrates point, line, and polygon data for the US East Coast into 0.250 latitude {times} 0.250 longitude grid cells. Each coastal grid cell contains data on geology, geomorpholog,elevation, wave heights, tidal ranges, shoreline displacement (erosion), and sea-level trends. These data are available as a Numeric Data Package (NDP), from the Carbon Dioxide Information Analysis Center, consisting of this document and a set of computerized data files. The documentation contains information on the methods used in calculating each variable, detailed descriptions of file contents and formats, and a discussion of the sources, restrictions, and limitations of the data. The data files are available on magnetic tape, on floppy diskettes, or through INTERNET.

  17. A coastal hazards data base for the US East Coast

    Energy Technology Data Exchange (ETDEWEB)

    Gornitz, V.M. (National Aeronautics and Space Administration, New York, NY (United States). Goddard Inst. for Space Studies); White, T.W. (Oak Ridge National Lab., TN (United States)); Daniels, R.C. (Energy, Environment and Resources Center, University of Tennessee, Knoxville, TN (United States))

    1992-08-01

    This document describes the contents of a digital data base that may be used by raster or vector geographic information systems (GIS) and non-GIS data bases to assess the risk of coastlines to erosion or sea level rise. The data base integrates point, line, and polygon data for the US East Coast into 0.250 latitude [times] 0.250 longitude grid cells. Each coastal grid cell contains data on geology, geomorpholog,elevation, wave heights, tidal ranges, shoreline displacement (erosion), and sea-level trends. These data are available as a Numeric Data Package (NDP), from the Carbon Dioxide Information Analysis Center, consisting of this document and a set of computerized data files. The documentation contains information on the methods used in calculating each variable, detailed descriptions of file contents and formats, and a discussion of the sources, restrictions, and limitations of the data. The data files are available on magnetic tape, on floppy diskettes, or through INTERNET.

  18. Sustained high βN plasmas on EAST tokamak

    Science.gov (United States)

    Gao, Xiang; the EAST team

    2018-05-01

    Sustained high normalized beta (βN ∼ 1.9) plasmas with an ITER-like tungsten divertor have been achieved on EAST tokamak recently. The high power NBI heating system of 4.8 MW and the 4.6 GHz lower hybrid wave of 1 MW were developed and applied to produce edge and internal transport barriers in high βN discharges. The central flat q profile with q (ρ) ∼ 1 at ρ safety factor q95 = 4.7 is identified by the multi-channel far-infrared laser polarimeter and the EFIT code. The fraction of non-inductive current is about 40%. The relation between fishbone activity and ITB formation is observed and discussed.

  19. Depositional environments of Late Triassic lake, east-central New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Hester, P.M. (Bureau of Land Management, Albuquerque, NM (USA))

    1989-09-01

    The Redonda Member of the Chinle Formation represents deposition in a large, polymictic lake during the Late Triassic (Norian) in east-central New Mexico. This study documents and defines an extensive lacustrine system situated in western Pangaea which was influenced by both tectonic and climatic events. Areal extent of the lake may have been as much as 5,000 km{sup 2}.

  20. Observation of internal transport barrier in ELMy H-mode plasmas on the EAST tokamak

    Science.gov (United States)

    Yang, Y.; Gao, X.; Liu, H. Q.; Li, G. Q.; Zhang, T.; Zeng, L.; Liu, Y. K.; Wu, M. Q.; Kong, D. F.; Ming, T. F.; Han, X.; Wang, Y. M.; Zang, Q.; Lyu, B.; Li, Y. Y.; Duan, Y. M.; Zhong, F. B.; Li, K.; Xu, L. Q.; Gong, X. Z.; Sun, Y. W.; Qian, J. P.; Ding, B. J.; Liu, Z. X.; Liu, F. K.; Hu, C. D.; Xiang, N.; Liang, Y. F.; Zhang, X. D.; Wan, B. N.; Li, J. G.; Wan, Y. X.; EAST Team

    2017-08-01

    The internal transport barrier (ITB) has been obtained in ELMy H-mode plasmas by neutron beam injection and lower hybrid wave heating on the Experimental Advanced Superconducting Tokamak (EAST). The ITB structure has been observed in profiles of ion temperature, electron temperature, and electron density within ρ safety factor q(0) ˜ 1. Transport coefficients are calculated by particle balance and power balance analysis, showing an obvious reduction after the ITB formation.

  1. Relations among Ethnic Identity, Parenting Style, and Adolescent Psychosocial Outcomes in European American and East Indian Immigrants.

    Science.gov (United States)

    Bhadha, Bakhtawar

    The challenges of identity formation are particularly difficult for minority youth because of the clash of traditional culture and the host culture. This study examined the effects of parenting style, acculturation, and parent and adolescent ethnic identity on the self-esteem and school performance of East Indian and European American adolescents.…

  2. The genus Cuscuta L. in East Asia

    Directory of Open Access Journals (Sweden)

    E. V. Aistova

    2015-07-01

    Full Text Available On the basis of published data, herbarium collections  and  our  own  research  the  overview  of  the spread  of  7  dodder  species  (genus  Cuscuta  on  the territory of  of the Russian Far East and East Asia is given. The  history  of  research  dodders  on  the  territory  of  the Russian Far East, ecological and spreading peculiarities are described. Certain eurytopic species (C. campestris Yunck., C. japonica Choisy and C. europaea L. growing on the territory of the Russian Far East have plasticity and  rapid  adaptive  response  for  changing  ecological and  geographical  conditions.  C.  epilinum  Weihe, C. epithymum (L. Nathh., C. tinei Insenga have not been naturalized in the Russian Far East.

  3. Forecasting of Currency Crises in East Asia

    Directory of Open Access Journals (Sweden)

    Chi-Young Song

    2005-06-01

    Full Text Available In this paper, we have developed a forecasting system for currency crisis in East Asia based on a signaling approach. Our system uses 15 monthly indicators of five East Asian countries including Indonesia, Korea, Malaysia, the Philippines and Thailand that were severely hit by the currency crisis in 1997. We investigate the performance of the system through deploying out-of-sample forecasting for the periods both before and after the 1997 East Asian currency crisis. Unlike the existing research based on the signaling approach, our out-of-sample forecasting does not fix the in-sample period. The out-of-sample forecasting between July 1995 and June 1997 shows that prior to breakout of the crisis, several indicators including real exchange rates and exports sent frequent warnings to all crisis-hit East Asian countries except the Philippines. This may indicate that a signaling-based early warning system for currency crisis could have been an useful method of forecasting the East Asian crisis. On the other hand, we also find that our forecasting system often generates warning signals during the out-of-sample period between July 1999 and June 2001. Since we have not observed any currency crisis in this region after 1998, these are all false alarms, indicating that our system may be seriously exposed to the type II error. We can, however, mitigate this problem if we adjust the optimal critical values of indicators depending on the preferences of forecasting system manager.

  4. Petrologic evolution of Miocene-Pliocene mafic volcanism in the Kangal and Gürün basins (Sivas-Malatya), central east Anatolia: Evidence for Miocene anorogenic magmas contaminated by continental crust

    Science.gov (United States)

    Kocaarslan, Ayça; Ersoy, E. Yalçın

    2018-06-01

    This study discusses the geochemical features of the Early-Middle Miocene and Pliocene basaltic (SiO2 = 46-52; MgO = 6-10 wt%) to andesitic (SiO2 = 59; MgO = 4 wt%) rocks exposed in the Gürün and Kangal basins (Sivas, eastern part of central Anatolia), respectively. The basaltic rocks are characterized by alkaline to tholeiitic affinities, while the more evolved andesitic samples show calc-alkaline affinity. Trace element variations reveal that they can be evaluated in three sub-groups, each represented by different contents of trace elements for given Nb contents. Primary magmas of each groups were likely produced by different degrees of partial melting ( 1-2, 2-3, 7-10% respectively) from a common mantle source, subsequently underwent different degrees of fractionation and crustal contamination. Derivation from a common mantle source of the primitive magmas of each group is supported by similar Sr, Nd and Pb isotopic ratios. Increasing degrees of partial melting seem to be responsible for the alkaline to tholeiitic variation among the basaltic samples, while higher degrees of crustal contamination (AFC) resulted in calc-alkaline affinity of the more evolved samples. Most primitive Pliocene samples show intra-plate (anorogenic) geochemical features, while the more evolved Miocene calc-alkaline samples resemble geochemically subduction-related (orogenic) magmatic rocks. However, on the basis of detailed geochemical models, we propose that the calc-alkaline affinity among the Miocene samples can also be gained by crustal contamination of their primary magmas which were also anorogenic in character. If this is true, overall, the Miocene and Pliocene basaltic to andesitic rocks in the Gürün and Kangal basins appear to may have formed by variable degrees of partial melting of a common anorogenic mantle that had not been subject to subduction-related metasomatism. This is an alternative approach to the general view assuming the Early-Middle Miocene magmatic activity in the region was derived from subduction-modified mantle sources in response to subduction of the Arabian Plate under the Anatolian Plate. This hypothesis further implies that either delamination of the sub-continental lithosphere or slab break-off processes beneath the central to eastern Anatolia might took place well before the Miocene, thus allowing upwelling unaltered mantle to provide the source of the Miocene to Pliocene volcanic rocks.

  5. Two types of gabbroic xenoliths from rhyolite dominated Niijima volcano, northern part of Izu-Bonin arc: petrological and geochemical constraints

    Science.gov (United States)

    Arakawa, Yoji; Endo, Daisuke; Ikehata, Kei; Oshika, Junya; Shinmura, Taro; Mori, Yasushi

    2017-03-01

    We examined the petrography, petrology, and geochemistry of two types of gabbroic xenoliths (A- and B-type xenoliths) in olivine basalt and biotite rhyolite units among the dominantly rhyolitic rocks in Niijima volcano, northern Izu-Bonin volcanic arc, central Japan. A-type gabbroic xenoliths consisting of plagioclase, clinopyroxene, and orthopyroxene with an adcumulate texture were found in both olivine basalt and biotite rhyolite units, and B-type gabbroic xenoliths consisting of plagioclase and amphibole with an orthocumulate texture were found only in biotite rhyolite units. Geothermal- and barometricmodelling based on mineral chemistry indicated that the A-type gabbro formed at higher temperatures (899-955°C) and pressures (3.6-5.9 kbar) than the B-type gabbro (687-824°C and 0.8-3.6 kbar). These findings and whole-rock chemistry suggest different parental magmas for the two types of gabbro. The A-type gabbro was likely formed from basaltic magma, whereas the B-type gabbro was likely formed from an intermediate (andesitic) magma. The gabbroic xenoliths in erupted products at Niijima volcano indicate the presence of mafic to intermediate cumulate bodies of different origins at relatively shallower levels beneath the dominantly rhyolitic volcano.

  6. Two types of gabbroic xenoliths from rhyolite dominated Niijima volcano, northern part of Izu-Bonin arc: petrological and geochemical constraints

    Directory of Open Access Journals (Sweden)

    Arakawa Yoji

    2017-03-01

    Full Text Available We examined the petrography, petrology, and geochemistry of two types of gabbroic xenoliths (A- and B-type xenoliths in olivine basalt and biotite rhyolite units among the dominantly rhyolitic rocks in Niijima volcano, northern Izu-Bonin volcanic arc, central Japan. A-type gabbroic xenoliths consisting of plagioclase, clinopyroxene, and orthopyroxene with an adcumulate texture were found in both olivine basalt and biotite rhyolite units, and B-type gabbroic xenoliths consisting of plagioclase and amphibole with an orthocumulate texture were found only in biotite rhyolite units. Geothermal- and barometricmodelling based on mineral chemistry indicated that the A-type gabbro formed at higher temperatures (899–955°C and pressures (3.6–5.9 kbar than the B-type gabbro (687–824°C and 0.8–3.6 kbar. These findings and whole-rock chemistry suggest different parental magmas for the two types of gabbro. The A-type gabbro was likely formed from basaltic magma, whereas the B-type gabbro was likely formed from an intermediate (andesitic magma. The gabbroic xenoliths in erupted products at Niijima volcano indicate the presence of mafic to intermediate cumulate bodies of different origins at relatively shallower levels beneath the dominantly rhyolitic volcano.

  7. Research on uranium and thorium elements exploration through the study of petrography, petrology and geophysical method in the Saghand Area (Central Iran) Islamic Republic of Iran

    International Nuclear Information System (INIS)

    Iranmanesh, J.; Fattahi, V.; Raziani, S.

    2014-01-01

    This study is a research on uranium and thorium exploration by use of the petrography, petrology and radiometric data in the Saghand area, Central Iran plateau. The lithologies of this area comprise of granite and metasomatized granite. As a result of metasomatic process, uranium and thorium bearing minerals such as davidite and alanite were formed. Sericitization and albitization are the main alterations detected in the study area and thorium mineralization is more common in albitization. By investigation of the chemical classification, non-radioactive specimens, rock types include: diorite and granodiorite, while radioactive specimens consist of gabbroic rocks (basalt). According to the magma source graphs, these rocks formed by calc-alkaline series magma. A scintillometer and spectrometer (MGS-150) were used for radiometric data acquisition. 1001 data points have been obtained from 11 profiles and total counts for, K, U, Th were measured. After primary data processing, data logarithms were calculated for normalizing, and the radiometric data show that uranium and thorium enrichment is more than potassium, while thorium and uranium enrichment are approximately equal. After data integration, two probable anomalies were determined in northwest and northeast parts of the study area. (author)

  8. Petrology, Magnetic susceptibility, Tectonic setting and mineralization associated with Plutonic and Volcanic Rocks, Eastern Bajestan and Taherabad, Iran

    Directory of Open Access Journals (Sweden)

    Malihe Ghoorchi

    2009-09-01

    Full Text Available Study area is located in district of Bajestan and Ferdows cities, NE of Iran. Structurally, this area is part of Lut block. The oldest exposed rocks, to the north of intrusive rocks and in Eastern Bajestan, are meta-chert, slate, quartzite, thin-bedded crystalline limestone and meta-argillite. The sedimentary units are: Sardar Formation (Carboniferous, Jamal Formation (Permian, Sorkh Shale and Shotori Formations (Triassic, carbonateous rocks (Cretaceous and lithostratigraphically equivalent to Kerman conglomerate (Cretaceous-Paleocene are exposed in this area. Based on relative age, magmatism in eastern Bajestan and Taherabad started after Late Cretaceous and it has been active and repeated during Tertiary time. At least, three episodes of volcanic activities are recognized in this area. The first stage was mainly volcanic flow with mafic composition and minor intermediate. The second episode was mainly intermediate in composition. The third stage was changed to acid-intermediate in composition. Since the plutonic rocks intruded the volcanic rocks, therefore they may be Oligo-Miocene age. Bajestan intrusive rocks are granite-granodiorite-quartz monzonite. Taherabad intrusive rocks are diorite-quartz diorite- monzonite-latite. Bajestan intrusive rocks are reduced type (ilmenite series and Taherabad intrusive rocks are oxidized type (magnetite series.Based on geochemical analysis including trace elements, REE and isotopic data, Bajestan intrusive rocks formed in continental collision zone and the magma has crustal origin. Taherabad intrusive rocks were formed in subduction zone and magma originated from oceanic crust. Taherabad intrusive rock has exploration potential for Cu-Au and pb.

  9. The geometry and stratigraphic position of the Maassluis Formation (western Netherlands and southeastern North Sea)

    NARCIS (Netherlands)

    Jansen, H.S.M.; Huizer, J.; Dijkmans, J.W.A.; Mesdag, C.; Hinte, J.E. van

    2004-01-01

    The geometry and depositional history of the Maassluis Formation is described from an East-West oriented transect located in the west-central Netherlands and P- and Q-blocks in the Dutch offshore area. The Late Pliocene to Early Pleistocene Maassluis Formation was deposited under near coastal marine

  10. Chapter 6. Tabular data and graphical images in support of the U.S. Geological Survey National Oil and Gas Assessment-East Texas basin and Louisiana-Mississippi salt basins provinces, Jurassic Smackover interior salt basins total petroleum system (504902), Travis Peak and Hosston formations.

    Science.gov (United States)

    ,

    2006-01-01

    This chapter describes data used in support of the process being applied by the U.S. Geological Survey (USGS) National Oil and Gas Assessment (NOGA) project. Digital tabular data used in this report and archival data that permit the user to perform further analyses are available elsewhere on the CD-ROM. Computers and software may import the data without transcription from the Portable Document Format files (.pdf files) of the text by the reader. Because of the number and variety of platforms and software available, graphical images are provided as .pdf files and tabular data are provided in a raw form as tab-delimited text files (.tab files).

  11. Source characteristics and tectonic setting of mafic-ultramafic intrusions in North Xinjiang, NW China: Insights from the petrology and geochemistry of the Lubei mafic-ultramafic intrusion

    Science.gov (United States)

    Chen, Bao-Yun; Yu, Jin-Jie; Liu, Shuai-Jie

    2018-05-01

    The newly discovered Lubei sulfide-bearing mafic-ultramafic intrusion forms the western extension of the Huangshan-Jin'erquan mafic-ultramafic intrusion belt in East Tianshan, NW China. The Lubei intrusion comprises hornblende peridotite, lherzolite, and harzburgite in its southern portion, gabbro in its middle portion, and hornblende gabbro in its northern portion. Intrusive relationships indicate that three magma pulses were involved in the formation of the intrusion, and that they were likely evolved from a common primitive magma. Estimated compositions of the Lubei primitive magma are similar to those of island arc calc-alkaline basalt except for the low Na2O and CaO contents of the Lubei primitive magma. This paper reports on the mineral compositions, whole-rock major and trace element contents, and Rb-Sr and Sm-Nd isotopic compositions of the Lubei intrusion, and a zircon LA-MC-ICP-MS U-Pb age for hornblende gabbro. The Lubei intrusion is characterized by enrichment in large-ion lithophile elements, depletion in high-field-strength elements, and marked negative Nb and Ta anomalies, with enrichment in chondrite-normalized light rare earth elements. It exhibits low (87Sr/86Sr)i ratios of 0.70333-0.70636 and low (143Nd/144Nd)i ratios of 0.51214-0.51260, with positive εNd values of +4.01 to +6.33. LA-ICP-MS U-Pb zircon ages yielded a weighted-mean age of 287.9 ± 1.6 Ma for the Lubei intrusion. Contemporaneous mafic-ultramafic intrusions in different tectonic domains in North Xinjiang show similar geological and geochemical signatures to the Lubei intrusion, suggesting a source region of metasomatized mantle previously modified by hydrous fluids from the slab subducted beneath the North Xinjiang region in the early Permian. Metasomatism of the mantle was dominated by hydrous fluids and was related to subduction of the Paleo-Asian oceanic lithosphere during the Paleozoic. Sr-Nd-Pb isotopic compositions suggest that the mantle source was a mixture of depleted mid

  12. Aligning petrology with geophysics: the Father's Day intrusion and eruption, Kīlauea Volcano, Hawai`i

    Science.gov (United States)

    Salem, L. C.; Edmonds, M.; Maclennan, J.; Houghton, B. F.; Poland, M. P.

    2016-12-01

    The Father's Day 2007 eruption at Kīlauea Volcano, Hawai`i, is an unprecedented opportunity to align geochemical techniques with the exceptionally detailed volcano monitoring data collected by the Hawaiian Volcano Observatory (HVO). Increased CO2 emissions were measured during a period of inflation at the summit of Kilauea in 2003-2007, suggesting that the rate of magma supply to the summit had increased [Poland et al., 2012]. The June 2007 Father's Day eruption in the East Rift Zone (ERZ) occurred at the peak of the summit inflation. It offers the potential to sample magmas that have ascended on short timescales prior to 2007 from the lower crust, and perhaps mantle, with limited fractionation in the summit reservoir. The bulk rock composition of the lavas erupted are certainly consistent with this idea, with >8.5 wt% MgO compared to a typical 7.0-7.5 wt% for contemporaneous Pu`u`O`o ERZ lavas. However, our analysis of the major and trace element chemistry of olivine-hosted melt inclusions shows that the melts are in fact relatively evolved, with Mg# eruptions, e.g. Kīlauea Iki. The magma evidently entrained a crystal cargo of more primitive olivines, compositionally typical of summit eruption magma (with 81-84 mol% Fo). The melt inclusion chemistry shows homogenized and narrowly distributed trace element ratios, medium/low CO2 abundances and high concentrations of sulfur (unlike typical ERZ magmas). However, the chemistry is unlike melts that have partially bypassed the summit reservoir, e.g. those erupted at Kīlauea Iki, Mauna Ulu. We suggest that the Father's Day magma had been resident in the magma reservoir prior to the 2003-2007 inflation, and was evacuated from the reservoir into the ERZ in response to the increased rate of intrusion of magma from depth. Dissolved volatile contents along profiles in embayments ("open" melt inclusions) were measured and compared to diffusion models to predict timescales of magma decompression prior to eruption. These are

  13. EAST ICRF system for long pulse operation

    International Nuclear Information System (INIS)

    Zhao, Y.P.; Zhang, X.J.; Mao, Y.Z.

    2013-01-01

    Radio frequency (RF) power in the ion cyclotron range of frequencies (ICRF) is one of the primary auxiliary heating techniques for Experimental Advanced Superconducting Tokamak (EAST). A 6.0 MW ICRF systems in the range of 25-70 MHz has been put into operation during the EAST 2012 spring campaign. The ICRF systems consist of two port-mounted antennas and each antenna is driven by two independent 1.5 MW RF power source. Another four 1.5 MW ICRF system is under way of construction.The system will deliver more than 10 MW of RF power to the plasma for 1000 sec pulse length. This paper gives brief introduction of the ICRF systems capability on EAST. (author)

  14. Recent progress with ICRF heating on EAST

    International Nuclear Information System (INIS)

    Zhang Xinjun; Zhao, Y.P.; Mao, Y.Z.

    2014-01-01

    Radio Frequency (RF) power in the ion cyclotron range of frequencies (ICRF) is one of the primary auxiliary heating techniques for Experimental Advanced Superconducting Tokamak (EAST). The ICRF system for the EAST has been developed to support long-pulse, high-β, advanced tokamak fusion physics experiments. The ICRF system can deliver 12 MW of RF power to the plasma for 1000 seconds through two antennas located in B- and I-ports. Each ICRF transmitter with high power up to 1.5 MW has been successfully tested on a dummy load. The main technical features of the ICRF system is described. Two simulation codes, TORIC (a full wave solver) and SSFPQL (the quasilinear Fokker-Planck solver), are combined to simulate the ICRF heating in the EAST 2D magnetic configuration. The fast wave propagation and absorption characteristics, power partitions among the plasma species and the RF driven energetic tails have been analyzed. (author)

  15. Uranium mineralization in the Lower Mahadek Sandstones of Laitduh Area, East Khasi Hills District, Meghalaya

    International Nuclear Information System (INIS)

    Mahendra Kumar, K.; Bhattacharjee, P.; Ranganath, N.

    2008-01-01

    Significant uranium mineralization hosted in feldspathic sandstone of Upper Cretaceous Lower Mahadek Formation has been located at Laitduh, East Khasi Hills district, Meghalaya. Two mineralized horizons have been identified within Lower Mahadek Formation with vertical separation of 30 m. Samples from upper horizon have assayed upto 0.17% U 3 O 8 , whereas samples from lower mineralized horizon have assayed upto 0.50% U 3 O 8 . The radioactive minerals identified are coffinite and pitchblende occurring in association with carbonaceous matter. (author)

  16. Radiative absorption enhancement of dust mixed with anthropogenic pollution over East Asia

    Directory of Open Access Journals (Sweden)

    P. Tian

    2018-06-01

    Full Text Available The particle mixing state plays a significant yet poorly quantified role in aerosol radiative forcing, especially for the mixing of dust (mineral absorbing and anthropogenic pollution (black carbon absorbing over East Asia. We have investigated the absorption enhancement of mixed-type aerosols over East Asia by using the Aerosol Robotic Network observations and radiative transfer model calculations. The mixed-type aerosols exhibit significantly enhanced absorbing ability than the corresponding unmixed dust and anthropogenic aerosols, as revealed in the spectral behavior of absorbing aerosol optical depth, single scattering albedo, and imaginary refractive index. The aerosol radiative efficiencies for the dust, mixed-type, and anthropogenic aerosols are −101.0, −112.9, and −98.3 Wm−2 τ−1 at the bottom of the atmosphere (BOA; −42.3, −22.5, and −39.8 Wm−2 τ−1 at the top of the atmosphere (TOA; and 58.7, 90.3, and 58.5 Wm−2 τ−1 in the atmosphere (ATM, respectively. The BOA cooling and ATM heating efficiencies of the mixed-type aerosols are significantly higher than those of the unmixed aerosol types over the East Asia region, resulting in atmospheric stabilization. In addition, the mixed-type aerosols correspond to a lower TOA cooling efficiency, indicating that the cooling effect by the corresponding individual aerosol components is partially counteracted. We conclude that the interaction between dust and anthropogenic pollution not only represents a viable aerosol formation pathway but also results in unfavorable dispersion conditions, both exacerbating the regional air pollution in East Asia. Our results highlight the necessity to accurately account for the mixing state of aerosols in atmospheric models over East Asia in order to better understand the formation mechanism for regional air pollution and to assess its impacts on human health, weather, and climate.

  17. Soviet and East European energy databook

    International Nuclear Information System (INIS)

    Wilson, D.C.

    1991-01-01

    For the USSR, energy data is assembled under the following main headings: energy and the economy; production; engineering; exploration; transport of fuel; refining; consumption by sector; employment; finance; trade; electricity. There are 162 tables. Five tables of data on Eastern Europe as a region cover production of energy, consumption, and exports of crude and oil products. Using similar broad headings as these for the USSR, a further 184 tables give data for the following individual countries: Bulgaria; Czechoslovakia; East Germany; Hungary; Poland; Romania; Yugoslavia. The data has been accumulated from Soviet and East European sources, mainly newspapers, journals, annual yearbooks and private contacts and the chief of these are listed. (UK)

  18. The Middle East, OPEC and oil

    International Nuclear Information System (INIS)

    Roberts, J.

    1996-01-01

    The importance of the Middle East to the oil industry, was discussed. The unresolved Arab-Israeli dispute and the ongoing conflicts in the Gulf are the two main reasons for political instability in the Middle East. This in turn, shapes the security of the region and its oil supplies. The factors which will shape the future of OPEC, including the Arab-Israeli conflict, the issue of the return of Iraqi crude to the market, and production decisions by Saudi Arabia were discussed in the context of their impact on OPEC's role as a coordinator of oil policies and of market stabilisation through price control

  19. Development of plasma fueling on EAST

    International Nuclear Information System (INIS)

    Yao, X.J.; Zheng, X.W.; Li, C.Z.; Chen, Y.

    2015-01-01

    To achieve better plasma density control, experimental advanced superconducting tokamak (EAST) has already equipped with gas puffing (GP), supersonic molecular beam injection (SMBI) and pellet injection (PI). During the past few years, lots of experiments and ameliorations have been done. The performance of the SMBI and gas puffing (GP) feedback systems were used and compared. And the preliminary result of pellet injection was also presented here. The results shows the PI and SMBI were more compatible to the long pulse high density discharge on EAST. (author)

  20. African Muslim Youth and the Middle East

    DEFF Research Database (Denmark)

    Ihle, Annette Haaber

    this African tradition of religious scholarship in the Middle East. The paper will, with the help of Pierre Bourdieu's notion of forms of capital related to various fields, analyse the challenges which Muslim students encounter during their stay in the Middle East and the forms of capital they bring back......, marked by economic decline and political instability. In Africa a weak or even failed state often means that young people have in reality no access to political, educational or economic positions and resources. In some countries like Nigeria, Ghana and the Ivory Coast the marginalisation of the youth...

  1. Upgrade of the synchronous data management system of the EAST poloidal field power supply

    International Nuclear Information System (INIS)

    Zhu, Lili; Huang, Liansheng; Fu, Peng; Gao, Ge; He, Shiying

    2016-01-01

    Highlights: • The upgraded synchronous data management system of EAST poloidal field power supply supports long-pulse data storage. • Slice storage mechanism on MDSplus has been adopted for quasi real-time data storage. • The state machine has been adopted for managing the system sequencer. • IEEE-1588 protocol via Ethernet for the synchronization of clock signal was detailed described. - Abstract: Poloidal field (PF) power supply is an important subsystem of the Experimental Advanced Superconducting Tokamak (EAST). The upgrade of the PF control system of EAST is a great improvement over the original data management system which could not meet the requirements necessary for experiments on synchronization, modularity and sampling rate. In order to better analyze the power operation performance, the Synchronization Data Management System (SDMS) needs to be upgraded as well. This upgrade is based on distributed data acquisition and an MDSPLUS database. It consists of three data acquisition nodes synchronized by an reference clock from the EAST central timing system that also provides the start trigger of the EAST pulse. After being processed by a signal conditioning unit, experimental signals are digitized and written into the database in MDSPLUS format. Multi-channel, multi-tasking and continuous data storage have been achieved by using multi-threading technology on a Linux operation system. The SDMS has been used on the server in PF control system for the entire 2015 EAST campaign. The SDMS has had good performance during experiments and convenient human-machine interface to satisfy the requirements of all the experiments.

  2. Upgrade of the synchronous data management system of the EAST poloidal field power supply

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Lili; Huang, Liansheng, E-mail: huangls@ipp.ac.cn; Fu, Peng; Gao, Ge; He, Shiying

    2016-11-15

    Highlights: • The upgraded synchronous data management system of EAST poloidal field power supply supports long-pulse data storage. • Slice storage mechanism on MDSplus has been adopted for quasi real-time data storage. • The state machine has been adopted for managing the system sequencer. • IEEE-1588 protocol via Ethernet for the synchronization of clock signal was detailed described. - Abstract: Poloidal field (PF) power supply is an important subsystem of the Experimental Advanced Superconducting Tokamak (EAST). The upgrade of the PF control system of EAST is a great improvement over the original data management system which could not meet the requirements necessary for experiments on synchronization, modularity and sampling rate. In order to better analyze the power operation performance, the Synchronization Data Management System (SDMS) needs to be upgraded as well. This upgrade is based on distributed data acquisition and an MDSPLUS database. It consists of three data acquisition nodes synchronized by an reference clock from the EAST central timing system that also provides the start trigger of the EAST pulse. After being processed by a signal conditioning unit, experimental signals are digitized and written into the database in MDSPLUS format. Multi-channel, multi-tasking and continuous data storage have been achieved by using multi-threading technology on a Linux operation system. The SDMS has been used on the server in PF control system for the entire 2015 EAST campaign. The SDMS has had good performance during experiments and convenient human-machine interface to satisfy the requirements of all the experiments.

  3. Disruption simulation for the EAST plasma

    International Nuclear Information System (INIS)

    Niu Xingping; Wu Bin

    2007-01-01

    The disruptions due to vertical displacement event for the EAST plasma are simulated in this article by using the TSC program. Meanwhile, the evolutions of the halo current and stress on vacuum vessel are calculated; the disruptions at different initial conditions are compared with each other, and killer pellet injection is simulated for the device fast shutting-down. (authors)

  4. Ice age plant refugia in East Greenland

    DEFF Research Database (Denmark)

    Funder, Svend Visby

    1979-01-01

    From the distribution of plants it has been inferred by some botanists that ice-free areas existed in East Greenland accommodating a flora which survived one or several ice ages in the area. Comparing this evidence with recent information on the chronology of glaciations and post-glacial vegetation...

  5. Educational Transition of East Malaysian Distance Learners.

    Science.gov (United States)

    Saw, K. G.; Awang, M. N.; Idrus, R. M.; Atan, H.; Azli, N. A.; Jaafar, I.; Rahman, Z. A.; Latiff, Z. A.

    1999-01-01

    Describes results of a study of the changing perceptions of East Malaysian distance learners studying at the Universiti Sains Malaysia. Highlights include students' perceptions of their study skills; and the impact of their studies on other areas of their life, including social obligations, recreation, families, health, finances, work, and…

  6. Journal of East African Natural History: Submissions

    African Journals Online (AJOL)

    2017-11-01

    Nov 1, 2017 ... Author Guidelines. Submission: manuscripts should be submitted as a Word document in an email attachment, to the Editor-in-Chief, Journal of East African Natural History at office@naturekenya.org. The manuscript should be accompanied by a covering letter from the author, or in the case of multiple ...

  7. Correlation Dynamics in East Asian Financial Markets

    NARCIS (Netherlands)

    Kuper, Gerard; Lestano, L

    2014-01-01

    This paper examines the dynamic relationship between stock returns and exchange rate changes using daily data from January 3, 1994 - September 27, 2013 for six East Asian countries: Indonesia, Malaysia, the Philippines, Singapore, South Korea and Thailand. We estimate conditional correlations using

  8. "Reading to Write" in East Asian Studies

    Science.gov (United States)

    Freedman, Leora

    2013-01-01

    A reading-writing initiative began in 2011-12 at the University of Toronto as a partnership between an East Asian Studies (EAS) department and an English Language Learning (ELL) Program. In this institution, students are expected to enter into scholarly discussions in their first year essays, yet many (both native English speakers and non-native…

  9. Financing Technological Upgrading in East Asia

    NARCIS (Netherlands)

    Rasiah, Rajah; Mubarik, Shujaat; Yap, Xiao-Shan

    2017-01-01

    There has been considerable discussion on the drivers of economic growth in East Asia. While most studies recognize that capital accumulation and macroeconomic management were critical in hastening growth, few have examined systematically and comparatively how policy frameworks – spearheaded through

  10. Correlation dynamics in East Asian financial markets

    NARCIS (Netherlands)

    Lestano, L; Kuper, Gerard H.

    2016-01-01

    We examine the dynamic relationship between stock returns and exchange rate changes using daily data from January 1994 to September 2013 for six East Asian countries. We use the multivariate GARCH-DCC model in order to disclose the relationship between stock markets and foreign exchange markets

  11. Five bid to host Middle East synchroton

    CERN Multimedia

    McCabe, H

    1999-01-01

    Germany is willing to donate a synchrotron to a research centre to be built somewhere in the Middle East. Bids to host the centre were submitted by Turkey, Cyprus, Iran, the Palestinian Authority and Egypt. Funding of at least 30 million US dollars still needs to be found (1 page).

  12. Ethnic entrepreneurship and internationalisation in East Africa

    NARCIS (Netherlands)

    Leendert de Bell; Hein Roelfsema; Khalidi Swabiri

    Using the World Bank Enterprise Surveys panel data for the East African Community, this paper analyses the influence of ethnic origin of entrepreneurs on internationalisation and firm performance. Using traditional probit and OLS estimation techniques in combination with matching strategies to

  13. Transmission of Middle East respiratory syndrome coronavirus ...

    African Journals Online (AJOL)

    ... hand hygiene, and cough etiquette, would minimize the infection rate among HCPs. The required consumables for maintaining hand hygiene should be readily available to all HCPs. Keywords: Middle East respiratory syndrome coronavirus (MERS-CoV), Systematic review, healthcareassociated infections, Coronaviruses ...

  14. Methane from the East Siberian Arctic shelf

    DEFF Research Database (Denmark)

    Petrenko...[], Vasilii V.; Etheridge, David M.

    2010-01-01

    In their Report “Extensive methane venting to the atmosphere from sediments of the East Siberian Arctic Shelf” (5 March, p. 1246), N. Shakhova et al. write that methane (CH4) release resulting from thawing Arctic permafrost “is a likely positive feedback to climate warming.” They add...

  15. Financing environmental policy in East Central Europe

    NARCIS (Netherlands)

    Kolk, A.; van der Weij, E.

    1998-01-01

    The transition in East Central Europe created a general optimism which was reflected in a belief that a solution to the environmental problems faced by these countries would be found. There were great expectations regarding the blessings of the market economy, which would diminish state-guided waste

  16. Consented Autopsy and the Middle-East.

    Science.gov (United States)

    Kharoshah, Magdy A; Hussain, Syed Ather; Madadin, Mohammed; Menezes, Ritesh G

    2017-02-01

    Consented autopsy is almost non-existent in the Middle-East where established social and cultural beliefs regarding the procedure might discourage family members from requesting a consented autopsy. Evidence suggests that new information is obtained from consented autopsies. It would not be in the best interest of medicine if social and cultural misconceptions succeed in erasing the existence of consented autopsies entirely.

  17. People and forests in East Kalimantan

    Science.gov (United States)

    Kuswata Kartawinata; Timothy C. Jessup; A. P. Vayda; S. Riswan; Cynthia Mackie; Nancy E. Peluso

    1992-01-01

    Two major Indonesian-MAB (Man and the Biosphere) projects were carried out in the province of East Kalimantan, Indonesia, in the 1980s. Investigators found that farmers vary in their reason for practicing shifting cultivation of logging and agriculture, in their intensity of farming, and in the amount of damage they caused forests in their practices. Shifting...

  18. East Africa’s Fragmented Security Cooperation

    DEFF Research Database (Denmark)

    Nordby, Johannes Riber; Jacobsen, Katja

    2013-01-01

    Since the 1990s, East Africa has developed what appears to be an impressive security architecture. Katja Lindskov Jacobsen and Johannes Riber Nordby warn, however, that appearances can be deceptive. The region’s security institutions remain too nationalistic and self-interested for their own good....

  19. East African Journal of Sciences: Editorial Policies

    African Journals Online (AJOL)

    Open Access Policy. This journal provides immediate open access to its content, upon registration, on the principle that making research freely available to the public supports a greater global exchange of knowledge. Creative Commons License East African Journal of Sciences by Haramaya University is licensed under a ...

  20. Housing East Asia: socioeconomic and demographic challenges

    NARCIS (Netherlands)

    Doling, J.; Ronald, R.

    2014-01-01

    Housing and home ownership has been strongly embedded in East Asian socioeconomic and policy models. Based on the primacy of national economic growth objectives, it was promoted as a means of, on the one hand, contributing directly to economic growth through the motor of the construction industry,

  1. National oil companies of South East Asia

    International Nuclear Information System (INIS)

    Singh, Gurdip

    1998-12-01

    Contains Executive Summary and Chapters on: Pertamina; Petronas; Petroleum Authority of Thailand; Philippines National Oil Company; Petro Vietnam; Myanmar Oil and Gas Enterprise; Singapore; Asean Free Trade Agreement, and Appendix on Petroleum tax legislation in the main south east Asian countries. (Author)

  2. East African Journal of Public Health

    African Journals Online (AJOL)

    The East African Journal of Public Health is a multi-disciplinary journal publishing scientific research work from a range of public health related disciplines including community medicine, epidemiology, nutrition, behavioural sciences, health promotion, health education, communicable and non-communicable disease.

  3. Assessing sanitary mixtures in East African cities

    NARCIS (Netherlands)

    Letema, S.C.

    2012-01-01

    The urbanisation of poverty and informality in East African cities poses a threat to environmental
    health, perpetuates social exclusion and inequalities, and creates service gaps (UN-Habitat, 2008).
    This makes conventional sanitation provision untenable citywide, giving rise to the

  4. Central control system for the EAST tokamak

    International Nuclear Information System (INIS)

    Sun Xiaoyang; Ji Zhenshan; Wu Yicun; Luo Jiarong

    2008-01-01

    The architecture, the main function and the design scheme of the central control system and the collaboration system of EAST tokamak are described. The main functions of the central control system are to supply a union control interface for all the control, diagnoses, and data acquisition (DAQ) subsystem and it is also designed to synchronize all those subsystem. (authors)

  5. Peculiarities of transformation processes in East Germany

    Directory of Open Access Journals (Sweden)

    Marion Dathe

    2011-03-01

    Full Text Available The process of socio-economic transformation of East German lands after the German reunification in 1990 is analyzed, the term "transformation" in frames of planned and market economies is defined. The author studies the historical determinants of the transformation process in Germany. German economic and industrial history in context of the driving forces and their social values, as well as the properties of the planning and economic systems that underlie the transformation of East German mentality, are considered. Further analysis is connected with economic, social and political components of the East German transformation process, "the dominance of the West", the collapse of the Council for Mutual Economic Assistance, privatization etc. Finally, the outcome of already traversed path of transformation of East Germany is considered. It is concluded, that the transformation process is not only historically conditioned situations of both the merging parties in the case of Germany, but also the positive or negative perception of its results and the motivation for its further implementation.

  6. East Midlands healthcare and bioscience sector strategy

    OpenAIRE

    East Midlands Development Agency

    2007-01-01

    The healthcare and bioscience sector is one of four priority sectors identified in the regional economic strategy, A Flourishing Region. This document sets out a strategy for maximising the contribution of the healthcare and biosciences sector to the economic development of the East Midlands.

  7. The Eichmann Trial on East German Television

    NARCIS (Netherlands)

    Keilbach, Judith

    2014-01-01

    abstractThe trial against Adolf Eichmann was one of the first transnational media events on television. Its world-wide coverage required transnational cooperation. Using East German television reports about the trial this article argues that although the event transcended national borders it

  8. The Eichmann Trial on East German Television

    Directory of Open Access Journals (Sweden)

    Judith Keilbach

    2014-06-01

    Full Text Available The trial against Adolf Eichmann was one of the first transnational media events on television. Its world-wide coverage required transnational cooperation. Using East German television reports about the trial this article argues that although the event transcended national borders it maintained at the same time ideological boundaries.

  9. Sponges from Clipperton Island, East Pacific

    NARCIS (Netherlands)

    van Soest, R.W.M.; Kaiser, K.L.; van Syoc, R.

    2011-01-01

    Twenty sponge species (totalling 190 individuals) were collected during the 1938, 1994 and 2004/5 expeditions to the remote island of Clipperton in the East Pacific Ocean. Seven species are widespread Indo-Pacific sponges; nine species comprise sponges new to science; four species were represented

  10. Soldiers and Civilians in Contemporary Middle East

    DEFF Research Database (Denmark)

    2017-01-01

    Despite the fact that the co-called Arab Spring has spread promising winds across the Middle East and the Northern Afria (MENA) region over the past decade, several countries in the region have nevertheless been caught up in devastating and destructive intra-state conflicts. A prevailing trend...

  11. Progress of the EAST project in China

    International Nuclear Information System (INIS)

    Wan, Y.X.; Wu, S.T.; Weng, P.D.; Li, J.G.; Gao, D.M.

    2005-01-01

    The Experimental Advanced Superconducting Tokamak (EAST) project is one of the National Mega-Projects of Science Research of China, which was approved by Chinese government in 1998. EAST is a full superconducting tokamak with an elongated plasma cross-section. The mission of the project is to widely investigate both of the physics and the technologies of advanced tokamak operations, especially the mechanism of power and particle handling for steady-state operations. The basic requirements for the EAST tokamak are full superconducting coils, suitable inductive current system, continuous working non-inductive current driven and heating systems, flexible operation scenarios, flexible J(r) and P(r) control, reliable and fast plasma positioning and shaping control, changeable plasma facing components, advanced divertor and diagnostics. Significant progress of the EAST project has been achieved during last two years. The R and D programs, mainly focused on the superconducting magnets, have processed successfully. The prototypes of main parts have been fabricated and qualified. Most of the key parts of the machine have been delivered to the assembly site. The assembly of the device has begun. It is planned to obtain the first plasma in 2005. The detail information of the testing results of superconducting magnets will be given in this paper. The assembly plan and the experimental plan will be introduced, too. (author)

  12. Suprasubduction volcanic rocks of the Char ophiolite belt, East Kazakhstan: new geochemical and first geochronological data

    Science.gov (United States)

    Safonova, Inna; Simonov, Vladimir; Seltmann, Reimar; Yamamoto, Shinji; Xiao, Wenjiao

    2016-04-01

    -1530°C and 14-26 kbar and crystallized at 1150-1190°C (Simonov et al., 2010). All these features are indicative of a supra-subduction origin of rocks. The age of gabbro, dolerite, andesite and tonalite was determined by LA ICP MS U-Pb zircon dating performed in the University of Kyoto, Japan. The andesites and tonalites yielded Carboniferous ages of ca. 322-336 Ma and the gabbro and dolerite appeared Devonian (387-395 Ma). Thus, the Char volcanic rocks possess geochemical signatures of supra-subduction magmas and could be derived at high degree melting of relatively shallow mantle sources. The volcanic units probably formed at one or two island-arcs or at an intra-oceanic arc and continental margin arc during the Middle Devonian - Mississippian. Later, the island-arc units were probably accreted to the active margin of the Kazakhstan continent. The work was supported by RFBR Project no. 16-05-00313. Contribution to IGCP#592 of UNESCO-IUGS. Safonova, I.Yu., Simonov V.A., Kurganskaya E.V., Obut O.T., Romer R.L., Seltmann R., 2012. Late Paleozoic oceanic basalts hosted by the Char suture-shear zone, East Kazakhstan: geological position, geochemistry, petrogenesis and tectonic setting. Journal of Asian Earth Sciences 49, 20-39. Simonov V.A., Safonova I.Yu., Kovyazin S.V., 2010. Petrogenesis of island-arc complexes of the Char zone, East Kazakhstan. Petrology 18, 59-72.

  13. East African Journal of Public Health: Journal Sponsorship

    African Journals Online (AJOL)

    East African Journal of Public Health: Journal Sponsorship. Journal Home > About the Journal > East African Journal of Public Health: Journal Sponsorship. Log in or Register to get access to full text downloads.

  14. Scopus: Journal of East African Ornithology: Journal Sponsorship

    African Journals Online (AJOL)

    Scopus: Journal of East African Ornithology: Journal Sponsorship. Journal Home > About the Journal > Scopus: Journal of East African Ornithology: Journal Sponsorship. Log in or Register to get access to full text downloads.

  15. East and Central African Journal of Surgery: About this journal

    African Journals Online (AJOL)

    East and Central African Journal of Surgery: About this journal. Journal Home > East and Central African Journal of Surgery: About this journal. Log in or Register to get access to full text downloads.

  16. Archives: East and Central African Journal of Surgery

    African Journals Online (AJOL)

    Items 1 - 40 of 40 ... Archives: East and Central African Journal of Surgery. Journal Home > Archives: East and Central African Journal of Surgery. Log in or Register to get access to full text downloads.

  17. Detection of phylogenetic extraction of sheep populations in East ...

    African Journals Online (AJOL)

    USER

    2010-06-28

    Jun 28, 2010 ... populations in East and South Asia based on fuzzy ... Based on the previous research, according to the Hierarchy clustering, the sheep populations in East and South ... have been known and some data have been obtained,.

  18. ISSN 2073 ISSN 2073 9990 East Cent. Afr. J. 9990 East Cent. Afr. J ...

    African Journals Online (AJOL)

    Hp 630 Dual Core

    COSECSA/ASEA Publication East and Central African ... the one hand on medical technology and equipment and on the other hand on the medical .... traumatic brain injury was the main cause of death amongst emergency admissions at the.

  19. ISSN 2073 ISSN 2073 9990 East Cent. Afr. J. s 9990 East Cent. Afr.

    African Journals Online (AJOL)

    Hp 630 Dual Core

    she went abroad to South East Asia to seek better medical care. ... developed deep venous thrombosis and pulmonary thrombo embolism eventually ... lengthy procedures, change in nursing staff during procedures and failure to count surgical ...

  20. Technical diagnosis system for EAST tokamak

    International Nuclear Information System (INIS)

    Qian Jing; Weng, P.D.; Luo, J.R.; Chen, Z.M.; Wu, Y.

    2010-01-01

    Technical diagnosis system (TDS) is one of the important subsystems of EAST (experimental advanced superconducting tokamak) device, main function of which is to monitor status parameters in EAST device. Those status parameters include temperature of different positions of main components, resistance of each superconducting (SC) coils, joint resistance of SC coils and high-temperature superconducting (HTS) current leads, strain of cold-quality components endured force, and displacement and current of toroidal field (TF) coils in EAST device, which are analog input signals. In addition there are still some analog and digital output signals. The TDS monitors all of those signals in the period of EAST experiments. TDS data monitoring is described in detail for it plays important role during EAST campaign. And how to protect the SC magnet system during each plasma discharging is presented with data of temperature of coolant inlet and outlet of SC coils and feeders and cases of the TF coils and temperature in the upper and middle and bottom of the TF coil case. During construction of the TDS primary difficulties come from installation of Lakeshore Cernox temperature sensors, strain measurement of central solenoid coils support legs and installation of co-wound voltage sensors for quench detection. While during operation since the first commissioning big challenges are from temperature measurement changes in current leads and quench detection of PF coils. Those difficulties in both stages are introduced which are key to make the TDS reliable. Meanwhile analysis of experimental data like temperature as a back up to testify quench occurrence and stress on vacuum vessel thermal shield and vacuum vessel have also been discussed.