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Sample records for argentina petrology geochronology

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

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    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...

  2. Geochronology of La Tinta Upper Proterozoic sedimentary rocks, Argentina

    International Nuclear Information System (INIS)

    Cingolani, C.A.; Bonhomme, M.G.

    1982-01-01

    Olavarria-Sierras Bayas, Barker-San Manuel and Balcarce-Mar del Plata fine-grained sedimentary rocks from La Tinta Formation, the pre-Cenozoic cover of the Tandilia region, were studied using the Rb-Sr and K-Ar geochronology. The mineralogical study of the fine fraction has shown that only the Olavarria-Sierras Bayas area presents suitable material comprising typical sedimentary clays, affected only by diagenetic processes. Two Rb-Sr isochrons were obtained from Olavarria-Sierras Bayas rocks. They show: (1) an age of 769 +- 12 Ma with ( 87 Sr/ 86 Sr) 0 = 0.7121 +- 0.0005, for Aust Quarry rocks; and (2) an age of 723 +- 21 Ma with ( 87 Sr/ 86 Sr) 0 = 0.7171 +- 0.0012 for Cerro Negro and Losa Quarries rocks. Considering the above-mentioned isochron data and the mineralogy of the clays studied, the conclusion is drawn that the ages obtained reflect the isotopic setting of a late diagenetic process, dated back to nearly 720 Ma. K-Ar data also support the Rb-Sr isochrons and the late diagenetic clay origin. The lower section of La Tinta sequence in the Sierras Bayas area must then be considered as Upper Proterozoic in age. These new data support the recently reported stratigraphical divisions and ages. (Auth.)

  3. 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

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

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    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

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

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    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

  6. Channel flow and localized fault bounded slice tectonics (LFBST): Insights from petrological, structural, geochronological and geospeedometric studies in the Sikkim Himalaya, NE India

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    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

  7. Structural, petrological and geochronological analysis of the lithotypes from the Pien region (Parana State, Brazil) and adjacences

    International Nuclear Information System (INIS)

    Harara, Ossama Mohamed

    1996-01-01

    The Pien area presents the major geotectonic domains separated by the Pien Shear Zone (PSZ). The northern one is the Rio Pien Granite-Mylonitic Suite composed by calc-alkaline granitoids of Neoproterozoic age. The southern domain is represented by the Amphibolite-Granulite where high grade metamorphism took place at the end of paleoproterozoic time. Considering the identified lithotypes, their geochemical affinity (particularly the Ti, Cr, Ni and REE content) and the geological context observed in the area, a geotectonical model of active continental margin related to subduction SSZ (Supra-Subduction Zone) is proposed. K-Ar on plagioclase from gabbronorites gave Neoproterozoic ages although Sm-Nd whole rock isochron yielded Paleoproterozoic ages. Based in geochemical data, it is proposed that the biotite gneiss and biotite-amphibole-gneiss which occur near the PSZ have a shoshonitic to high-K calc-alkaline features which are characteristic of active continental margins. K-Ar on biotite extracted from these rocks, gave Neoproterozoic ages. The available radiometric data for the Rio Pien mylonitic granitoids show that between 650-595 Ma the generation, deformation and cooling below the isotherm of 250 deg C occurred. On the other hand, the geochronological data for the Agudos do Sul Massif are in the 590-570 Ma interval showing its younger generation. The Sr 87 / Sr 86 initial ratios for both granitoids suggest more involvement of the continental crust in the origins of Agudos do Sul granitic Massif. The analyses of the entire set of the available data for the Pien area allows the suggestion of a geotectonic scenery related to the evolution of an active continental margin during the collages associated to the Brasiliano Cycle

  8. Petrologic and zircon U-Pb geochronological characteristics of the pelitic granulites from the Badu Complex of the Cathaysia Block, South China

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    Zhao, Lei; Zhou, Xiwen; Zhai, Mingguo; Liu, Bo; Cui, Xiahong

    2018-06-01

    The recognition of the Indosinian Orogeny in the South China block has been controversial and difficult because of strong weathering and thick cover. High temperature (HT) and high pressure (HP) metamorphic rocks related to this orogeny were considered to be absent from this orogenic belt until the recent discovery of eclogite and granulite facies meta-igneous rocks, occurring as lenses within the meta-sedimentary rocks of the Badu Complex. However, metamorphic state of these meta-sedimentary rocks is still not clear. Besides, there have been no geochronological data of HT pelitic granulites previously reported from the Badu Complex. This paper presents petrographic characteristics and zircon geochronological results on the newly discovered kyanite garnet gneiss, pyroxene garnet gneiss and the HT pelitic granulites (sillimanite garnet gneiss). Mineral assemblages are garnet + sillimanite + ternary feldspar + plagioclase + quartz + biotite for the HT pelitic granulite, kyanite + ternary feldspar + garnet + sillimanite + plagioclase + quartz + biotite for the kyanite garnet gneiss, and garnet + biotite + pyroxene + plagioclase + ternary feldspar + quartz for the pyroxene garnet gneiss, respectively. Decompressional coronas around garnet grains can be observed in all these pelitic rocks. Typical granulite facies mineral assemblages and reaction textures suggest that these rocks experienced HP granulite facies metamorphism and overprinted decompression along a clockwise P-T loop. Results from integrated U-Pb dating and REE analysis indicate the growth of metamorphic zircons from depleted heavy REE sources (100-50 chondrite) compared with detrital zircons derived from granitic sources (typically > 1000 chondrite). Metamorphic zircons in HP granulite exhibit no or subdued negative Eu anomalies, which perhaps indicate zircon overgrowth under eclogite facies conditions. The zircon overgrowth ages range from 250 to 235 Ma, suggesting that HP granulite (eclogite) to

  9. The petrology, geochronology and significance of Granite Harbour Intrusive Complex xenoliths and outcrop sampled in western McMurdo Sound, Southern Victoria Land, Antarctica

    International Nuclear Information System (INIS)

    Martin, A.P.; Cooper, A.F.; Price, R.C.; Turnbull, R.E.; Roberts, N.M.W.

    2015-01-01

    Granite Harbour Intrusive Complex xenoliths in McMurdo Volcanic Group rocks and in situ outcrops have been studied from Mount Morning, western McMurdo Sound, Antarctica. Calc-alkalic samples have whole rock signatures and normative compositions similar to the Dry Valleys 1b suite, and zircon grains in one specimen yield a 545.2 ± 4.4 Ma crystallisation age. This supports subduction-related magmatism initiating in Southern Victoria Land by 545 Ma. A second group of xenoliths is alkalic, with titanite grains in one xenolith from this group dated at 538 ± 8 Ma. Whole rock chemistry, normative compositions and geochronology of the alkalic group are comparable to the Koettlitz Glacier Alkaline Suite (KGAS). The position of a proposed lower crustal discontinuity that may form a significant basement suture in the McMurdo Sound region is newly constrained to the east of Mount Morning, perhaps along the trace of the Discovery Glacier. The boundary between East and West Antarctica may also pass along the trace of the Discovery Glacier if, as previously hypothesised, its location is controlled by the basement suture. A significant basement suture may also have provided the necessary egress for the (regionally) early and sustained magmatic activity observed at Mount Morning over the last 24 million years. (author).

  10. Geology, petrology, U-Pb (SHRIMP) geochronology of the Morrinhos granite - Paragua terrane, SW Amazonian craton: implications for the magmatic evolution of the San Ignacio orogeny

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    Franca, Ohana; Ruiz, Amarildo Salina; Sousa, Maria Zelia Aguiar de, E-mail: ohana.geo@gmail.com, E-mail: asruiz@gmail.com, E-mail: mzaguiar@terra.com.br [Universidade Federal de Mato Grosso (UFMT), Cuiaba, MT (Brazil). Instituto de Ciencias Exatas e da Terra. Dept. de Geologia Geral; Batata, Maria Elisa Froes, E-mail: elisabatata@bol.com.br [Universidade Federal de Mato Grosso (UFMT), Cuiaba, MT (Brazil). Grupo de Pesquisa em Evolucao Crustal e Tectonica; Lafon, Jean-Michel [Universidade Federal do Para (GEOCIAM/UFPA), Belem, PR (Brazil). Inst. Nacional de Cencia e Tecnologia de Geociencias da Amazonia

    2014-09-15

    Morrinhos granite is a batholith body that is slightly elongated in the NNW direction and approximately 1,140 km{sup 2} long; it is located in the municipality of Vila Bela da Santissima Trindade of the state of Mato Grosso, Brazil, in the Paragua Terrane, Rondonian-San Ignacio Province, in the SW portion of the Amazonian Craton. This intrusion displays a compositional variation from tonalite to monzogranite, has a medium to coarse inequigranular texture and is locally porphyritic; biotite is the predominant mafic in one of the facies, and hornblende is predominant in the other, with both metamorphosed into the green schist facies. The studied rocks characterize an intermediate to acidic sequence that was formed by a subalkaline magmatism; the series is alkali-calcic to metaluminous to slightly peraluminous, and the rocks evolved through fractioned crystallization mechanisms. The structural data show two deformation phases represented by penetrative foliation (S{sub 1}) and open folds (D{sub 2}), and both phases were most likely related to the San Ignacio Orogeny. The geochronological (U-Pb SHRIMP) and isotopic (Sm-Nd) investigations of these rocks indicated a crystallization age of 1350±12Ma, T{sub DM} of approximately 1.77 Ga and εNd{sub (1.35}) with a negative value of -2.57, suggesting that their generation was related to a partial melting process of a Paleoproterozoic (Statherian) continental crust. The results herein indicate that the Morrinhos granite was generated in a continental magmatic arc in a late- to post-orogenic stage of the San Ignacio Orogeny, and it can be recognized as belonging to the Pensamiento Intrusive Suite. (author)

  11. Petrological, geochemical, isotopic, and geochronological constraints for the Late Devonian-Early Carboniferous magmatism in SW Gondwana (27-32°LS): an example of geodynamic switching

    Science.gov (United States)

    Dahlquist, Juan A.; Alasino, Pablo H.; Basei, Miguel A. S.; Morales Cámera, Matías M.; Macchioli Grande, Marcos; da Costa Campos Neto, Mario

    2018-04-01

    We report a study integrating 13 new U-Pb LA-MC-ICP-MS zircon ages and Hf-isotope data from dated magmatic zircons together with complete petrological and whole-rock geochemistry data for the dated granitic rocks. Sample selection was strongly based on knowledge reported in previous investigations. Latest Devonian-Early Carboniferous granite samples were collected along a transect of 900 km, from the inner continental region (present-day Eastern Sierras Pampeanas) to the magmatic arc (now Western Sierras Pampeanas and Frontal Cordillera). Based on these data together with ca. 100 published whole-rock geochemical analyses we conclude that Late Devonian-Early Carboniferous magmatism at this latitude represents continuous activity (ranging from 322 to 379 Ma) on the pre-Andean margin of SW Gondwana, although important whole-rock and isotopic compositional variations occurred through time and space. Combined whole-rock chemistry and isotope data reveal that peraluminous A-type magmatism started in the intracontinental region during the Late Devonian, with subsequent development of synchronous Carboniferous peraluminous and metaluminous A-type magmatism in the retro-arc region and calc-alkaline magmatism in the western paleomargin. We envisage that magmatic evolution was mainly controlled by episodic fluctuations in the angle of subduction of the oceanic plate (between flat-slab and normal subduction), supporting a geodynamic switching model. Subduction fluctuations were relatively fast (ca. 7 Ma) during the Late Devonian and Early Carboniferous, and the complete magmatic switch-off and switch-on process lasted for 57 Ma. Hf T DM values of zircon (igneous and inherited) from some Carboniferous peraluminous A-type granites in the retro-arc suggest that Gondwana continental lithosphere formed during previous orogenies was partly the source of the Devonian-Carboniferous granitic magmas, thus precluding the generation of the parental magmas from exotic terranes.

  12. Emplacement, petrological and magnetic susceptibility characteristics of diverse magmatic epidote-bearing granitoid rocks in Brazil, Argentina and Chile

    Science.gov (United States)

    Sial, A. N.; Toselli, A. J.; Saavedra, J.; Parada, M. A.; Ferreira, V. P.

    1999-03-01

    Magmatic epidote (mEp)-bearing granitoids from five Neoproterozoic tectonostratigraphic terranes in Northeastern (NE) Brazil, Early Palaeozoic calc-alkalic granitoids in Northwestern (NW) Argentina and from three batholiths in Chile have been studied. The elongated shape of some of these plutons suggests that magmas filled fractures and that dyking was probably the major mechanism of emplacement. Textures reveal that, in many cases, epidote underwent partial dissolution by host magma and, in these cases, may have survived dissolution by relatively rapid upward transport by the host magma. In plutons where such a mechanism is not evident, unevenly distributed epidote at outcrop scale is armoured by biotite or near-solidus K-feldspar aggregates, which probably grew much faster than epidote dissolution, preventing complete resorption of epidote by the melt. Al-in-hornblende barometry indicates that, in most cases, amphibole crystallized at P≥5 kbar. Kyanite-bearing thermal aureoles surrounding plutons that intruded low-grade metamorphic rocks in NE Brazil support pluton emplacement at intermediate to high pressure. mEp show overall chemical variation from 20 to 30 mol% (mole percent) pistacite (Ps) and can be grouped into two compositional ranges: Ps 20-24 and Ps 27-30. The highest Ps contents are in epidotes of plutons in which hornblende solidified under Pcorrosion of individual epidote crystals included in plagioclase in high-K calc-alkalic granitoids in NE Brazil, emplaced at 5-7 kbar pressure, yielded estimates of magma transport rate from 70 to 350 m year -1. Most of these plutons lack Fe-Ti oxide minerals and Fe +3 is mostly associated with the epidote structure. Consequently, magnetic susceptibility (MS) in the Neoproterozoic granitoids in NE Brazil, as well as Early Palaeozoic plutons in Argentina and Late Palaeozoic plutons in Chile, is usually low (3.0×10 -3 SI, typical of magnetite-series granitoids crystallized under higher oxygen fugacity. In NE

  13. Subduction of Proterozoic to Late Triassic continental basement in the Guatemala suture zone: A petrological and geochronological study of high-pressure metagranitoids from the Chuacús complex

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    Maldonado, Roberto; Ortega-Gutiérrez, Fernando; Ortíz-Joya, Guillermo A.

    2018-05-01

    Many continental subduction complexes contain abundant granitic rocks coexisting with minor volumes of eclogite-facies rocks. Characterization of granitic protoliths is crucial to decipher the origin of subducted continental crust, whereas knowledge of its metamorphic evolution is required to constrain the mechanisms of burial and exhumation. In this work we present geochronological and petrological evidence that demonstrate the occurrence of a subducted Proterozoic to Late Triassic granitic basement in the Chuacús complex of central Guatemala. Metagranitoids exposed in this area are interlayered with eclogite and other high-pressure rocks, and their structure is considerably variable due to strain partitioning during deformation. Laser ablation-inductively coupled plasma-mass spectrometry U-Pb zircon data from two ferroan metagranites yield protolith crystallization ages of ca. 1.1 Ga and their trace-element abundances suggest an origin related to intraplate magmatism, while a high-silica, peraluminous metagranite is dated at 1.0 Ga and was probably originated by partial melting of a high-grade continental crust. On the other hand, two megacrystic to augen metagranitoids yield protolith crystallization ages of ca. 224 Ma, which are identical within errors to the protolith age of hosted eclogitic metabasites. Their high incompatible trace element abundances together with the observed spatial-temporal relationships with mafic protoliths suggest that Late Triassic bimodal magmatism in the Chuacús complex was probably originated in a within-plate setting. Regardless of their age or structure, the studied metagranites preserve evidences for high-pressure metamorphic equilibration, such as the occurrence of Ca-rich garnet (XCa up to 0.52) in association with phengite (Si contents of up to 3.4 pfu) and rutile. The integration of Zr-in-rutile thermometry and phengite barometry allows the peak metamorphic conditions to be constrained at 640-680 °C and 13 kbar. This

  14. 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

  15. High resolution crustal structure for the region between the Chilenia and Cuyania terrane above the Pampean flat slab of Argentina from local receiver function and petrological analyses

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    Ammirati, J. B.; Alvarado, P. M.; Pérez, S. B.; Beck, S. L.; Porter, R. C.; Zandt, G.

    2015-12-01

    Jean-Baptiste Ammirati 1,Sofía Perez 1, Patricia Alvarado 1, Susan L. Beck 2, Ryan Porter 3 and George Zandt 2(1) CIGEOBIO-CONICET, Universidad Nacional de San Juan, Argentina (2) The University of Arizona, USA (3) Northern Arizona University, USA At ~31ºS, The subduction of the Nazca plate under the South American plate presents along-strike variations of its dip angle referred to the Chilean-Pampean flat slab. Geological observations suggest that the regional crustal structure is inherited from the accretion of different terranes at Ordovician times and later reactivated during Andean compression since Miocene. Geophysical observations confirmed that the structure is extending in depth with décollement levels that accommodate crustal shortening in the region. In order to get a better insight on the shallow tectonics we computed high frequency local receiver functions from slab seismicity (~100 km depth). Local earthquakes present a higher frequency content that permits a better vertical resolution. Using a common conversion point (CCP) stacking method we obtained cross sections showing high-resolution crustal structure in the western part of the Pampean flat slab region, at the transition between the Precordillera and the Frontal Cordillera. Our results show a well-defined structure and their lateral extent for both units down to 80 km depth. In good agreement with previous studies, our higher resolution images better identify very shallow discontinuities putting more constraints on the relationships with the regional structural geology. Recent petrological analyses combined with RF high-resolution structure also allow us to better understand the regional crustal composition. Interestingly, we are able to observe a shifting structure beneath the Uspallata-Calingasta Valley, highlighting the differences in terms of crustal structure between the Precordillera and the Frontal Cordillera. Previously determined focal mechanisms in the region match well this

  16. Argentina.

    Science.gov (United States)

    1986-06-01

    This discussion of Argentina covers geography, the people, history and political conditions, government, economy, foreign relations, and relations between the US and Argentina. In 1985, the population of Argentina was estimated to be 30.6 million with an estimated annual growth rate of 1.5%. The infant mortality rate is 34.1/1000, and life expectancy is 70.2 years. Argentina, which shares land borders with Bolivia, Brazil, Chile, Paraguay, and Uruguay, is bounded by the Atlantic and the Antarctic Oceans. Descendants of Italian and Spanish immigrants predominate in Argentina, but many trace their origins to British and West and East European ancestors. In recent years, there has been a substantial influx of immigrants from neighboring Latin American countries. The native Indian population, estimated to be 50,000, is concentrated in the peripheral provinces of the north, northwest, and south. What is now Argentina was discovered in 1516 by the Spanish navigator Juan de Solia. The formal declaration of independence from Spain was made on July 9, 1816. In the late 19th century, 2 forces worked to create the modern Argentine nation: the introduction of modern agricultural techniques and the integration of Argentina into the world economy. Argentina has impressive human and natural resources, but political conflict and uneven economic performance since World War II have impeded full realization of its considerable potential. Yet, it is one of the wealthiest countries in Latin America. Among the reasons for the military coup of March 1976 was the deteriorating economy, caused by declining production and rampant inflation. Under the leadership of the Minister of the Economy, the military government focused attention on those immediate problems, and, in 1978, embarked on a new development strategy focusing on the establishment of a free market economy. There was little improvement in the economy, and a new economic plan was introduced in 1985 which has capped inflation by

  17. Stratigraphy, geochronology, and paleoenvironments of Miocene - Pliocene boundary of San Fernando, Belén (Catamarca, northwest of Argentina)

    Science.gov (United States)

    Bonini, Ricardo A.; Georgieff, Sergio M.; Candela, Adriana M.

    2017-11-01

    The Santa María-Hualfín Basin was proposed as a regional synchronous lithostratigraphic depocenter in the geological province of Northwestern Pampean Ranges, Northwestern Argentina. However, new 40Ar-39Ar dating indicates that deposits toward the east, in Santa María Valley (Santa María Department), are younger than the western depocenter in San Fernando (Belén Department). Therefore, it would be more appropriate to study these valleys as separate basins, each one with its own tecto-sedimentary features. The east basin, named in this paper Villavil-Quillay, constitutes an elongated independent basin that developed along the front of the eastern Puna bordering with Papachacra and Durazno Ranges. This basin is composed of more than 3000 m of mudstone, sandstone, conglomerates, volcaniclastic and pyroclastic deposits. Villavil-Quillay basin develops onto a peneplain of Precambrian and lower Cambrian rocks, most of which are metamorphic and granites rocks. The sedimentary fill consists of Cretaceous? and Cenozoic continental deposits. The Cenozoic record is composed of a) the Santa María Group (Miocene-Pliocene), formed by Las Arcas, Chiquimil, Andalhuala and Corral Quemado Formations, and b) the Punaschotter unit (Puna's Gravels in German, Pleistocene). This study involves the Andalhuala, Corral Quemado and Punaschotter deposits cropping out in San Fernando area. The set of identified facies assemblage corresponding to the Andalhuala Formation shows a vertical variation of fluvial sub-environments, varying from permanent sandy braided rivers to gravel rivers and aeolian dunes culminating in an alluvial dry cycle. While facies assemblages of the Corral Quemado Formation allow inferring the development of ephemeral water bodies from secondary channels on the floodplain, the Punaschotter conglomerates indicate the development of gravel channels and bars. Three samples of tuffs interbedded in the sedimentary levels of Andalhuala Formation were dated indicating that

  18. Argentina

    International Nuclear Information System (INIS)

    Masters, R.

    1997-01-01

    This article provides information on the energy resources, government, electricity supply, nuclear industry and fuel cycle of Argentina. About 12% of electric power produced is generated from nuclear power plants. The operating capacity, history and partial privatisation of the nuclear industry are covered, and fuel cycle facilities described. These include uranium mining and processing, enrichment, fuel fabrication and heavy water production. (UK)

  19. Argentina

    International Nuclear Information System (INIS)

    2001-04-01

    This economical study summarizes the energy situation of Argentina: energy institutions and policy, energy companies (oil, electricity, gas, coal), energy supplies (resources, power production, petroleum, natural gas), prices and tariffs, consumption, economical stakes and perspectives (investments, agreements, projects). Energy data for the 1971-1999 period are summarized in graphs and tables. (J.S.)

  20. Argentina

    Energy Technology Data Exchange (ETDEWEB)

    1999-09-01

    This report presents a brief overview of the socio-economic, energy and environmental context in which climate change mitigation actions in Argentina shall be inserted. To that end, the dynamic of the Argentine economic development, its influence on the energy system and environmental impacts is summarised. From the environmental standpoint, emphasis shall only be made on the impact of economic development patterns and energy policies on GHG emission. (au) 73 refs.

  1. Argentina

    International Nuclear Information System (INIS)

    Tanis, S.; Ramberg, B.

    1990-01-01

    Argentina has embarked on an ambitious domestic nuclear research and energy program. The venture promises to provide the nation with the infrastructure to play an important role in the nuclear export market in the years ahead. Buenos Aires built its program on a foundation of international support and assistance that overlay an emerging sophisticated industrial and scientific establishment. The foreign contribution sensitized Argentina to opportunities in the global market. This paper reports that Argentina operates two heavy-water/natural uranium reactors, Atucha I and Embalse. Producing, respectively, 320 MW(e) and 600 MW(e), they supply roughly 10 percent of the country's electricity. With a capacity factor of 84 percent, Atucha I is among the best operated plants in the world. Plans call for a third, 745 MW(e) power plant, Atucha II, to go on line in the early 1990s. During this period, construction also may begin on three 300 MW(e) plants, although the country's foreign indebtedness plus cost overruns in earlier construction will place a heavy burden on these plans

  2. Argentina

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This paper reports that like so many other countries, Argentina is in the throes of privatization and restructuring of its economic programs. This has had a direct effect on the LPG industry. Argentina is a country with many natural resources. However, natural gas and crude, while present, are not in abundance. Imports of these and their associated products are needed to satisfy the growing need of the population from time to time. This is especially true with LPGs. Production of the fuel averages about 1 million tons, not enough to satisfy internal needs in the winter but enough to permit some exports in the summer to nearby Brazil. The Country's Congress approved a plan to sell-off or lease parts of the natural gas distribution network and other businesses of Gas del Estado. Subsequent new legislation has called for ten new natural gas distribution zones. Included in the sell-off is the company's propane distribution division. What is left of Gas del Estado and YPF will become a corporation in the true sense of the word. Stocks in YPF are to be sold to the public

  3. Petrology and geochemistry of the Los Cuartos granite, Tafi del Valle, Tucuman, northwest of Argentina: its integration to the regional magmatic layout; Petrologia y geoquimica del granito Los Cuartos, Tafi del Valle, Tucuman, noroeste de Argentina: integracion al esquema magmatico regional

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, J.P.; Bellos, L.I.

    2010-07-01

    Los Cuartos Granite crops out on the western flank of the Cumbres Calchaquies, east of Tafi del Valle, Tucuman Province, Argentina. It has a granitic to granodioritic composition, of two micas, being biotite dominant. The granite is medium grained and inequigranular, with rare K-feldspar megacrysts. It contains host-rock xenoliths with different degrees of assimilation. The granite intrusion produced contact metamorphism in the surrounding basement, with development of andalucite porphyroblasts and poikiloblastic biotite. The granite is calk-alkaline and peraluminous, and is K- and P-rich and Ca- and Napoor compared to other granitoids of the region. The pluton shows late-tectonic features with regard to the regional deformation. The granite possibly intruded during the Ordovician (Famatinian Cycle) and its emplacement was structurally controlled by the Tafi Megafracture. Los Cuartos Granite and other intrusive bodies of the region share similar petrographical, geochemical, structural and geochronological characteristics. (Author).

  4. Argentina.

    Science.gov (United States)

    1993-02-01

    Background notes on Argentina provide a profile of the geography, selected demographic features, government and economic conditions. Descriptive text includes a discussion of the people, their history and political conditions, the government and officials, the state of the economy, their defense, foreign relations, and relations with the US. The 1992 estimated population was about 33 million of whom 97% are European (mostly Spanish and Italian). Religions represented are Roman Catholic (92%), Protestant (2%), Jewish (2%), and other (4%). Adult literacy is 95%. 36% are engaged in industry and commerce, 20% in services, 19% in agriculture, 6% in transport and communications, and 19% other. Per capita gross domestic product was $4,500. There are only 50,000 native Indians remaining in peripheral provinces. The population enjoys a high standard of living and a low growth rate. The country was shaped by dominant forces: modern agricultural techniques and the integration of the country into the world economy. Foreign investment aided the economic revolution. Conservative and radical rule has swung the country back and forth politically since 1916. Colonel Juan Domingo Peron led a successful military coup in 1943 and was elected in 1946. Policies were instituted to give a greater voice to the working class, and with the influences of his wife, women's groups. In 1955, he was ousted by the military, which failed to revive the economy and quiet increasing terrorism. After a number of difficult elections, Peron was reinstated as president in 1973. Extremists on the left and right threatened public order; the military as a consequence imprisoned persons indefinitely. Peron's wife succeeded him after his death, but was removed from office in the military coup of 1976. Basic human rights were violated during this period. By 1983, a fair election was held and support increased for a democratic system. In 1989, Carlos Saul Menem, a Peronist candidate, won and established

  5. Argentina

    Directory of Open Access Journals (Sweden)

    G. Benedetti

    2007-01-01

    Full Text Available El presente trabajo tiene como objetivo realizar un diagnóstico ambiental de un sector de la ciudad de Bahía Blanca, Argentina basado en el arbolado urbano de alineación. El arbolado constituye un componente fundamental de los paisajes artifi ciales ya que contribuye al aumento del confort y al mejoramiento de la calidad del medio. En este sentido, actúa como un factor moderador de las condiciones climáticas, la contaminación y la salud de la población. El municipio de la ciudad de Bahía Blanca tiene como proyecto la realización de inventarios del arbolado en los distintos barrios, para lograr optimizar la relación entre la cantidad de ejemplares arbóreos y la densidad poblacional. Es importante considerar la variedad de ejemplares en función del uso del suelo y de las características ambientales de cada sector. Por lo tanto, este trabajo presenta un diseño metodológico para la elaboración del plano verde de la ciudad.

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

    Directory of Open Access Journals (Sweden)

    Ivana A Urraza

    2011-01-01

    Full Text Available En la presente contribución se dan a conocer los resultados parciales de un estudio de detalle de los eventos magmáticos, metamórficos y tectónicos acaecidos en el Complejo Ígneo-Metamórfico Aluminé (CIMA. Se define como CIMA al conjunto de rocas ígneas intrusivas preandinas y andinas y su encajonante metamórfico, aflorantes en el área comprendida entre los lagos Aluminé, Moquehue, Ñorquinco y Pulmarí, en la provincia de Neuquén, Argentina. Sobre la base de las observaciones de campo y de las características petrográficas y geoquímicas, las rocas granitoides constituyentes del CIMA han sido clasificadas como: 1. dioritas cuarzosas, 2. tonalitas-granodioritas, 3. granodioritas y 4. granitos. Los parámetros geoquímicos indican que las litologías definidas derivan de magmas calcicos a levemente calcoalcalinos, de composición metaaluminosa, típicos de los batolitos Tipo I Cordilleranos asociados a márgenes continentales activos. Intercalados entre las rocas magmáticas se preservan afloramientos de basamento metamórfico compuestos por esquistos, gneises, anfibolitas y escasas areniscas cuarzosas. Cubriendo en parte a las metamorfitas y granitoides, se reconocen andesitas, tobas y basaltos. La estructura del sector se caracteriza por la presencia de tres conjuntos de lineamientos regionales principales con orientaciones NE-SW, NW-SE y N-S. Estas direcciones coinciden con las orientaciones de tres grupos de foliaciones penetrativas reconocidas en las rocas magmáticas del sector. Sobre la base del análisis petrográfico-microestructural y de mecanismos de deformación en minerales, se identificaron al menos dos eventos de deformación dúctil en las rocas magmáticas del área. Los mapeos de campo y estudios petrológicos y estructurales llevados a cabo hasta el presente, permitieron diferenciar dos sectores con características claramente contrastantes: el sector norte caracterizado por el predominio de granitoides con edades

  7. 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.

  8. Petrology, geochemistry and LA-ICP-MS U-Pb geochronology of Paleoproterozoic basement rocks in Bangladesh: An evaluation of calc-alkaline magmatism and implication for Columbia supercontinent amalgamation

    Science.gov (United States)

    Hossain, Ismail; Tsunogae, Toshiaki; Tsutsumi, Yukiyasu; Takahashi, Kazuki

    2018-05-01

    The Paleoproterozoic (1.7 Ga) basement rocks from Maddhapara, Bangladesh show a large range of chemical variations (e.g. SiO2 = 50.7-74.7%) and include diorite, quartz diorite, monzodiorite, quartz monzonite and granite. The pluton overall displays metaluminous, calc-alkaline orogenic suite; mostly I-type suites formed within subduction-related magmatism. The observed major elements show general trends for fractional crystallization. Trace element contents also indicate the possibility of a fractionation or assimilation; explain the entire variation from diorite to monzonite, even granite. The pluton may have evolved the unique chemical features by a process that included partial melting of calc-alkaline lithologies and mixing of mantle-derived magmas, followed by fractional crystallization, and by assimilation of country rocks. The pluton shows evidence of crystal fractionation involving largely plagioclase, amphibole and possibly biotite. Some of the fractionated magmas may have mixed with more potassic melts from distinct parts of the continental lithosphere to produce granites and/or pegmatites. New geochronological results of granitic pegmatite (1722 ± 10 Ma) are indisputably consistent with diorite and tonalite and those data showing credible geochronological sequence (i.e., diorite - tonalite - granitic pegmatite). Identical Paleoproterozoic age (1.7 Ga) with distinctive magmatism of the Maddhapara basement rocks have agreeable relationship with the CITZ, India. The consistent magmatism is also common in the Transamazonian of South America, Trans-Hudson orogeny in North America, Bohemian Massif and the Svecofennian, Poland, have identified the sequential growth of the continent through the amalgamation of juvenile terrains, succeeded by a major collisional orogeny. Such Paleoproterozoic subduction-related orogens in Australia have similar counterparts in Antarctica and other part of the world. These types of Paleoproterozoic magmatism dominantly contributed

  9. Petrología y geoquímica del granito Los Cuartos, Tafí del Valle, Tucumán, noroeste de Argentina: integración al esquema magmático regional

    Directory of Open Access Journals (Sweden)

    López, J. P.

    2010-12-01

    Full Text Available Los Cuartos Granite crops out on the western flank of the Cumbres Calchaquíes, east of Tafí del Valle, Tucumán Province, Argentina. It has a granitic to granodioritic composition, of two micas, being biotite dominant. The granite is medium grained and inequigranular, with rare K-feldspar megacrysts. It contains host-rock xenoliths with different degrees of assimilation. The granite intrusion produced con tact metamorphism in the surrounding basement, with development of andalucite porphyroblasts and poikiloblastic biotite. The granite is calk-alkaline and peraluminous, and is K- and P-rich and Ca- and Na poor compared to other granitoids of the region. The pluton shows late-tectonic features with regard to the regional deformation. The granite possibly intruded during the Ordovician (Famatinian Cycle and its emplacement was structurally controlled by the Tafí Megafracture. Los Cuartos Granite and other intrusive bodies of the region share similar petrographical, geochemical, structural and geochronological characteristics.

    El Granito Los Cuartos aflora sobre la ladera occidental de Cumbres Calchaquíes, al E de la localidad de Tafí del Valle, provincia de Tucumán, Argentina. Es de composición granítica a granodiorítica, con desarrollo de dos micas, predominando la biotita. Es de grano medio e inequigranular, con megacristales de feldespato potásico raros o ausentes. Contiene xenolitos de la roca de caja con diferentes grados de digestión. Este cuerpo desarrolla fenómenos de metamorfismo de contacto en el basamento al que intruye, con desarrollo de porfiroblastos de andalucita y biotita poiquiloblástica. El granitoide presenta características calcoalcalina, peraluminosos, rico en K y P y con contenidos comparativamente más bajos en Ca y Na que los granitoides del área; poseen rasgos tardío-tectónicos con respecto a la deformación y su emplazamiento se habría producido durante el Ordovícico (Ciclo Famatiniano.

  10. Linking microstructures, petrology and in situ U-(Th)-Pb geochronology to constrain P-T-t-D evolution of the Greather Himalyan Sequences in Western Nepal (Central Himalaya)

    Science.gov (United States)

    Iaccarino, Salvatore; Montomoli, Chiara; Carosi, Rodolfo; Langone, Antonio

    2013-04-01

    Last advances in forward modelling of metamorphic rocks and into the understanding of accessories minerals behaviour, suitable for geochronology (e.g. zircon and monazite), during metamorphism, bring new insights for understanding the evolution of metamorphic tectonites during orogenic cycles (Williams and Jercinovic, 2012 and reference therein). One of the best exposure of high- to medium grade- metamorphic rocks, is represented by the Greater Himalayan Sequence (GHS) in the Himalayan Belt, one of the most classic example of collisional orogen. Recent field work in Mugu Karnali valley, Western Nepal (Central Himalaya), identified a compressional top to the South ductile shear zone within the core of the GHS, named Magri Shear Zone (MSZ), developed in a high temperature regime as testified by quartz microstructures and syn-kinematic growth of sillimanite. In order to infer the tectono-metamorphic meaning of MSZ, a microstructural study coupled with pseudosection modelling and in situ U-(Th)-Pb monazite geochronology was performed on selected samples from different structural positions. Footwall sample constituted by (Grt + St ± Ky) micaschist shows a prograde garnet growth (cores to inner rims zoning), from ~500°C, ~0.60GPa (close to garnet-in curve) to ~580°C, ~1.2 GPa temporal constrained between 21-18 Ma, by medium Y cores to very low Y mantles monazite micro-chemical/ages domain . In this sample garnet was still growing during decompression and heating at ~640°C, ~0.75 GPa (rims), and later starts to be consumed, in conjunction with staurolite growth at 15-13 Ma, as revealed by high Y rims monazite micro-chemical/ages domain. Hanging-wall mylonitic samples have a porphyroclastic texture, with garnet preserve little memory of prograde path. Garnet near rim isoplets and matrix minerals intersect at ~700°C and ~0.70 GPa. A previous higher P stage, at ~1.10 GPa ~600°C, is testified by cores of larger white mica porhyroclasts. Prograde zoned allanite (Janots

  11. Geology, petrology, U-Pb (shrimp geochronology of the Morrinhos granite -Paraguá terrane, SW Amazonian craton: implications for the magmatic evolution of the San Ignácio orogeny

    Directory of Open Access Journals (Sweden)

    Ohana França

    Full Text Available Morrinhos granite is a batholith body that is slightly elongated in the NNW direction and approximately 1,140 km2 long; it is located in the municipality of Vila Bela da Santíssima Trindade of the state of Mato Grosso, Brazil, in the Paraguá Terrane, Rondonian-San Ignácio Province, in the SW portion of the Amazonian Craton. This intrusion displays a compositional variation from tonalite to monzogranite, has a medium to coarse inequigranular texture and is locally porphyritic; biotite is the predominant mafic in one of the facies, and hornblende is predominant in the other, with both metamorphosed into the greenschist facies. The studied rocks characterize an intermediate to acidic sequence that was formed by a subalkaline magmatism; the series is alkali-calcic to metaluminous to slightly peraluminous, and the rocks evolved through fractioned crystallization mechanisms. The structural data show two deformation phases represented by penetrative foliation (S1 and open folds (D2, and both phases were most likely related to the San Ignácio Orogeny. The geochronological (U-Pb SHRIMP and isotopic (Sm-Nd investigations of these rocks indicated a crystallization age of 1350 ± 12 Ma, TDMof approximately 1.77 Ga and εNd(1.35with a negative value of -2.57, suggesting that their generation was related to a partial melting process of a Paleoproterozoic (Statherian continental crust. The results herein indicate that the Morrinhos granite was generated in a continental magmatic arc in a late- to post-orogenic stage of the San Ignácio Orogeny, and it can be recognized as belonging to the Pensamiento Intrusive Suite.

  12. Structural, petrological and geochronological analysis of the lithotypes from the Pien region (Parana State, Brazil) and adjacences; Analise estrutural, petrologica e geocronologica dos litotipos da Regiao de Pien (PR) e adjacencias

    Energy Technology Data Exchange (ETDEWEB)

    Harara, Ossama Mohamed

    1996-12-31

    The Pien area presents the major geotectonic domains separated by the Pien Shear Zone (PSZ). The northern one is the Rio Pien Granite-Mylonitic Suite composed by calc-alkaline granitoids of Neoproterozoic age. The southern domain is represented by the Amphibolite-Granulite where high grade metamorphism took place at the end of paleoproterozoic time. Considering the identified lithotypes, their geochemical affinity (particularly the Ti, Cr, Ni and REE content) and the geological context observed in the area, a geotectonical model of active continental margin related to subduction SSZ (Supra-Subduction Zone) is proposed. K-Ar on plagioclase from gabbronorites gave Neoproterozoic ages although Sm-Nd whole rock isochron yielded Paleoproterozoic ages. Based in geochemical data, it is proposed that the biotite gneiss and biotite-amphibole-gneiss which occur near the PSZ have a shoshonitic to high-K calc-alkaline features which are characteristic of active continental margins. K-Ar on biotite extracted from these rocks, gave Neoproterozoic ages. The available radiometric data for the Rio Pien mylonitic granitoids show that between 650-595 Ma the generation, deformation and cooling below the isotherm of 250 deg C occurred. On the other hand, the geochronological data for the Agudos do Sul Massif are in the 590-570 Ma interval showing its younger generation. The Sr{sup 87} / Sr{sup 86} initial ratios for both granitoids suggest more involvement of the continental crust in the origins of Agudos do Sul granitic Massif. The analyses of the entire set of the available data for the Pien area allows the suggestion of a geotectonic scenery related to the evolution of an active continental margin during the collages associated to the Brasiliano Cycle 201 refs., 130 figs., 6 tabs., 2 maps

  13. Structural, petrological and geochronological analysis of the lithotypes from the Pien region (Parana State, Brazil) and adjacences; Analise estrutural, petrologica e geocronologica dos litotipos da Regiao de Pien (PR) e adjacencias

    Energy Technology Data Exchange (ETDEWEB)

    Harara, Ossama Mohamed

    1997-12-31

    The Pien area presents the major geotectonic domains separated by the Pien Shear Zone (PSZ). The northern one is the Rio Pien Granite-Mylonitic Suite composed by calc-alkaline granitoids of Neoproterozoic age. The southern domain is represented by the Amphibolite-Granulite where high grade metamorphism took place at the end of paleoproterozoic time. Considering the identified lithotypes, their geochemical affinity (particularly the Ti, Cr, Ni and REE content) and the geological context observed in the area, a geotectonical model of active continental margin related to subduction SSZ (Supra-Subduction Zone) is proposed. K-Ar on plagioclase from gabbronorites gave Neoproterozoic ages although Sm-Nd whole rock isochron yielded Paleoproterozoic ages. Based in geochemical data, it is proposed that the biotite gneiss and biotite-amphibole-gneiss which occur near the PSZ have a shoshonitic to high-K calc-alkaline features which are characteristic of active continental margins. K-Ar on biotite extracted from these rocks, gave Neoproterozoic ages. The available radiometric data for the Rio Pien mylonitic granitoids show that between 650-595 Ma the generation, deformation and cooling below the isotherm of 250 deg C occurred. On the other hand, the geochronological data for the Agudos do Sul Massif are in the 590-570 Ma interval showing its younger generation. The Sr{sup 87} / Sr{sup 86} initial ratios for both granitoids suggest more involvement of the continental crust in the origins of Agudos do Sul granitic Massif. The analyses of the entire set of the available data for the Pien area allows the suggestion of a geotectonic scenery related to the evolution of an active continental margin during the collages associated to the Brasiliano Cycle 201 refs., 130 figs., 6 tabs., 2 maps

  14. U-Pb geochronology of modern river sands from the flat-slab segment of the southern central Andes, Argentina, 29-31°S: Implications for Neogene foreland and hinterland basin evolution

    Science.gov (United States)

    Capaldi, T.; Horton, B. K.; McKenzie, R.; Stockli, D. F.

    2015-12-01

    This study investigates how Andean river sediments in the flat-slab segment of western Argentina record active mixing of lithologically and geochemically distinct source regions comprising the Principal Cordillera, Frontal Cordillera, Precordillera fold-thrust belt, Sierras Pampeanas basement uplifts, and recycled Neogene basin fill. Detrital zircon U-Pb geochronological results for modern river sands discriminate variations from hinterland source regions, through river tributaries and main trunks of the Bermejo, Jachal, San Juan, and Mendoza rivers, and their respective fluvial megafans within the active foreland basin. Proportions of proximal zircon populations in the hinterland trunk rivers (with extensive Permian-Triassic and Cenozoic igneous exposures) diminish downstream with progressive contributions from the frontal Precordillera fold-thrust belt (dominantly Paleozoic sedimentary rocks) and Pampean basement uplifts. However, this systematic downstream dilution is perturbed in several catchments by significant recycling of older foreland basin fill. The degree of recycling depends on the position and extent of Oligocene-Pliocene exposures within the catchments. To discern the effects of the variable detrital zircon sources, multiple statistical methods are utilized. Quantitative comparisons suggest that variations in detrital zircon age distributions among the modern sands, and with older foreland basin fill and exposed bedrock, are dependent on spatial and temporal variations in exhumation and drainage network evolution within their respective Andean catchments. The present surface area of competing source regions and the configuration of hinterland tributary rivers largely dictate the degree of downstream dilution and/or recycling. This study provides a modern analogue and baseline for reconstructing Neogene shifts in foreland basin provenance, depositional systems, and drainage configurations during a critical transition to flat-slab subduction.

  15. U-Pb geochronology of Martín García, Sola, and Dos Hermanas Islands (Argentina and Uruguay): Unveiling Rhyacian, Statherian, Ectasian, and Stenian of a forgotten area of the Río de la Plata Craton

    Science.gov (United States)

    Santos, João O. S.; Chernicoff, Carlos J.; Zappettini, Eduardo O.; McNaughton, Neal J.; Greau, Y.

    2017-12-01

    The Río de la Plata Craton is one of the three major cratons of South America. The craton is largely covered by sedimentary basins where its most exposed area is Buenos Aires-Piedra Alta Province (Chernicoff et al., 2014). This province includes the Martín García Island in the confluence of Uruguay River and the Río de la Plata estuary. Despite to be a reference area for the craton the Martín García Island lacks modern geological investigation. We present U-Pb SIMS (secondary ion mass spectrometer) geochronological data on zircon and titanite, as well as Hf isotope determinations on zircon, from rocks of Martín García Island (Argentina), Sola and Dos Hermanas Islands (Uruguay) and from Paso Severino Formation (Uruguay). We investigated: 1) Rhyacian intermediate-to acidic plutonic, arc-type rocks of the Florida Belt dated between 2090 Ma and 2115 Ma, derived from juvenile Neoarchean crust (TDMHf: 2.52 Ga; average εHf: +3.62); 2) Rhyacian metadacite (San José metamorphic belt) of 2127 Ma; 3) Statherian metagabbros of 1724-1734 Ma, with Transplatense inheritance; 4) Early Ectasian metagabbro of 1392 Ma, with Rhyacian inheritance; and 5) Stenian metagabbros of 1193 Ma (TDMHf: 2.00 Ga, εHf: 0.1). Most of the dated orthogneisses show Brasilian-age (from 778 to 550 Ma) Pb loss in the zircons, interpreted to be caused by shearing or uplifting during Neoproterozoic. The results show that the area is not exclusively Rhyacian in age but encompasses Statherian, Ectasian, and Stenian gabbros. The last two are interpreted as distal intrusions associated to the Sunsás Orogen. All post-Transplatense metagabbros have geochemical signature of island arc basalt derived from primitive mantle with enrichment of LILE and depletion of HFSE. These characteristics point to the recurrence of magma chambers intermittently active during the Rhyacian, Statherian, Ectasian, and Stenian, all with a similar source. The term "Transplatense" is used to replace "Trans-Amazonian" events

  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. Geochronologic study of polycyclic rocks from Sao Vicente complex in anticlinorium of Caico and Florania - RN, Brazil

    International Nuclear Information System (INIS)

    Pessoa, D.A.R.

    1976-01-01

    The characterization of geochronologic standard in a polycyclic area, verifying the interpretative potentials of Rubidium-Strontium and Potassium-Argon methods is the main objective of this paper. The determinations of K/Ar were made in amphiboles, moscovites and biotites. Petrology studies were also made for verifying the composition of several lithological types. (author)

  18. 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)

  19. 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.

  20. Geology, petrology and U-Pb geochronology of Serra da Rajada Granitic Pluton: implications about ediacaran magmatic evolution in NE portion of the Rio Piranhas-Serido Domain (NE of Borborema Province); Geologia, petrologia e geocronologia U-Pb do Pluton Granitico Serra da Rajada: implicacoes sobre a evolucao magmatica ediacarana na porcao do Dominio Rio Piranhas-Serido (NE da Provincia Borborema)

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Alan Pereira da; Dantas, Alexandre Ranier, E-mail: alan.costa@cprm.gov.br, E-mail: alexandre.dantas@cprm.gov.br [Servico Geologico do Brasil (CPRM), Natal, RN (Brazil). Nucleo de Apoio de Natal/Superintendencia Regional de Recife; Nascimento, Marcos Antonio Leite do; Galindo, Antonio Carlos, E-mail: marcos@geologia.ufrn.br, E-mail: galindo@geologia.ufrn.br [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Departamento de Geologia

    2015-12-15

    The Ediacaran plutonic activity, related to the Brazilian/Pan-African orogeny, is one of the most important geological features in the Borborema Province, formed by batholiths, stocks and dikes. The Serra da Rajada Granitic Pluton (SRGP), located in the central portion of the Rio Piranhas-Serido Domain, is an example of these bodies. This site is the target of cartographic, petrographic, lithochemical and geochronological studies. Its rocks are described as monzogranites consisting of K-feldspar, plagioclase (oligoclase-An{sub 23-24%}), quartz and biotite (main mafic), having as accessory minerals opaque, titanite, allanite, apatite and zircon. Chlorite, white mica and carbonate are alteration minerals. Lithochemical data from 15 samples show quite evolved rocks (SiO{sub 2} , 69% to 75%), rich in alkalis (Na{sub 2}O + K{sub 2}O ≥ 8.0%), depleted in MgO (≤ 0.45%), CaO (≤ 1.42%) and TiO{sub 2} (≤ 0.36%), and displaying moderate levels of Fe{sub 2}O{sub 3} t (2.16 to 3.53%). These rocks present a transitional nature between metaluminous and peraluminous (predominance of the latter) and have subalkaline/monzonitic affinity (high-K Calc-alkaline). Harker diagrams represent negative correlations in Fe{sub 2}O{sub 3}t, MgO and CaO, indicating fractionation of mafic and plagioclase. The REE spectrum show enrichment of light in relation to heavy REE (LaN/YbN = 23.70 to 10.13), with negative anomaly in Eu (Eu/ Eu* = 0.70 to 10.13) suggesting fractionation or accumulation in the feldspars source (plagioclase). Data integration allows correlating the SRGP rocks with those described as Equigranular high-K Calc-alkaline Suite. The U-Pb geochronology and Sm-Nd isotope dating indicate that the biotite monzogranite have a crystallization age of 557 ± 13 Ma and TDM model age of 2.36 Ga, respectively, and ε{sub Nd} value of - 20.10 for the crystallization age, allowing to infer a crustal source for the magma generated in the Paleoproterozoic age. (author)

  1. The Argon Geochronology Experiment (AGE)

    Science.gov (United States)

    Swindle, T. D.; Bode, R.; Fennema, A.; Chutjian, A.; MacAskill, J. A.; Darrach, M. R.; Clegg, S. M.; Wiens, R. C.; Cremers, D.

    2006-01-01

    This viewgraph presentation reviews the Argon Geochronology Experiment (AGE). Potassium-Argon dating is shown along with cosmic ray dating exposure. The contents include a flow diagram of the Argon Geochronology Experiment, and schematic diagrams of the mass spectrometer vacuum system, sample manipulation mechanism, mineral heater oven, and the quadrupole ion trap mass spectrometer. The Laser-Induced Breakdown Spectroscopy (LIBS) Operation with elemental abundances is also described.

  2. Petrology of the Miocene igneous rocks in the Altar region, main Cordillera of San Juan, Argentina. A geodynamic model within the context of the Andean flat-slab segment and metallogenesis

    Science.gov (United States)

    Maydagán, Laura; Franchini, Marta; Chiaradia, Massimo; Pons, Josefina; Impiccini, Agnes; Toohey, Jeff; Rey, Roger

    2011-07-01

    The Altar porphyry Cu-(Au-Mo) deposit (31° 29' S, 70° 28' W) is located in the Andean Main Cordillera of San Juan Province (Argentina), in the southern portion of the flat-slab segment (28-33°S), 25 km north of the world-class porphyry Cu-Mo deposits of Los Pelambres and El Pachón. Igneous rocks in the area have been grouped into the Early Miocene Lower Volcanic Complex -composed of intercalations of lava flows and thin volcaniclastic units that grade upwards to a thick massive tuff- and the Middle-Late Miocene Upper Subvolcanic Suite that consists of a series of porphyritic stocks and dikes and magmatic and hydrothermal breccias. The Lower Volcanic Complex represents an Early Miocene arc (20.8 Ma ± 0.3 Ma; U-Pb age) erupted over a steep subduction zone. Their magmas equilibrated with an assemblage consisting of plagioclase- and pyroxene-dominated mineral residues, and experienced fractional crystallization and crustal contamination procesess. Their radiogenic signatures are interpreted to indicate conditions of relatively thickened continental crust in Altar during the Early Miocene, compared to the south and west. The Upper Subvolcanic Suite represents the development of a Middle-Late Miocene arc (11.75 ± 0.24 Ma, 10.35 ± 0.32 Ma; U-Pb ages) emplaced over a shallow subduction zone. A magmatic gap in Altar area betwen the Lower Volcanic Complex and Upper Subvolcanic Suite correlates with documented higher rates of compression in this period, that may have favored the storage of the USS magmas in cameras within the crust. Magmas of the Upper Subvolcanic Suite require a hornblende-bearing residual mineral assemblage that is interpreted to reflect their higher water contents. The relatively uniform radiogenic isotope compositions of the Upper Subvolcanic Suite magmas suggest a homogeneously mixed crust-mantle contribution in the source region. They have similar REE signatures as other fertile intrusives of the flat-slab. The differences observed in their

  3. 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...

  4. U-Pb and Lu-Hf zircon geochronology of the Cañadón Asfalto Basin, Chubut, Argentina: Implications for the magmatic evolution in central Patagonia

    Science.gov (United States)

    Hauser, N.; Cabaleri, N. G.; Gallego, O. F.; Monferran, M. D.; Silva Nieto, D.; Armella, C.; Matteini, M.; Aparicio González, P. A.; Pimentel, M. M.; Volkheimer, W.; Reimold, W. U.

    2017-10-01

    The Cañadón Asfalto basin, central Chubut, Argentina, comprises a volcano-sedimentary sequence related to the opening of the Atlantic Ocean during Mesozoic times. The Lonco Trapial, Cañadón Asfalto and Cañadón Calcáreo formations are the main units related to the evolution of this basin. The Las Chacritas and Puesto Almada members are distinguished in the Cañadón Asfalto Formation. LA-HR-ICP-MS U-Pb and Lu-Hf data on zircon were obtained on these units. The Lonco Trapial Formation gave a weighted average age of 172.3 ± 1.8 Ma. A pyroclastic level from the Las Chacritas Member gave a weighted average age of 168.2 ± 2.2 Ma. Two U-Pb concordant ages of 160.3 ± 1.7 Ma on a laminated tuffite and 158.3 ± 1.3 Ma on a pyroclastic level were obtained for the Puesto Almada Member. Two maximum depositional ages constrain the sedimentary provenance areas for the basin: 1) A sample from the Sierra de la Manea range, where a controversial unit related either to the Cañadón Asfalto or to the Cañadón Calcáreo formation occurs, gave an age of 176.6 ± 1.0 Ma. Two younger zircon crystals indicate that this unit may be related to the Cañadón Calcáreo Formation. 2) A sandstone with cross-stratification from the Puesto Almada Member gave a maximum depositional age of 173.6 ± 6.4 Ma. In terms of U-Pb and Lu-Hf isotopes, two magmatic events are identified in central Patagonia: the Mamil Choique magmatic event characterized by negative εHf values around -5.0 and representing recycling during Permian times of Mesoproterozoic crust (TDM of ∼1.5 Ga), and the Cañadón Asfalto magmatic event with negative (-8.2) to positive (+4) εHf values and Meso- to Neoproterozoic TDM between 1.5 and 0.8 Ga. The younger event is characterized by three main cycles: C1 related to the Lonco Trapial magmatism, C2 to the Las Chacritas volcanism, and C3 to the Puesto Almada volcanism. These cycles are related with Marifil, Chon Aike and El Quemado formations volcanics events of

  5. Recent advances in quaternary geochronology

    International Nuclear Information System (INIS)

    Poupeau, G.

    1983-01-01

    Significant progress has occurred in quaternary geochronology. These include both (i) improvements in Fission Track and Thermoluminescence dating, as well as (ii) new technologies for short-lived (i.e. with half lives 6 yrs) radionuclide measurements as with the 14 C or uranium series desequilibrium dating, and finally (iii) the emergence of entirely new dating approches as the Electron Spin Resonnance Method. The aim of this paper is to review these progresses and the new areas they open geochronology for the past-miocene times. (author) [pt

  6. Petrology of the 1995/2000 Magma of Copahue, Argentina

    Science.gov (United States)

    Goss, A.; Varekamp, J. C.

    2001-05-01

    Phreatomagmatic eruptions of Copahue in July/August,1995 and July/August 2000 produced mixed juvenile clasts, silica-rich debris from the hydrothermal system, and magmatic scoria with 88 percent SiO2. These high-SiO2 clasts carry an as yet unidentified (crystobalite?), euhedral silica phase in great abundance, which is riddled with tan, primary melt inclusions. The mixed clasts have bands of mafic material with small euhedral olivine, clinopyroxene, and plagioclase that are mixed with an intermediate magma with coarser, resorbed phenocrysts of olivine, plagioclase, clino- and ortho- pyroxene, and rare occurrences of the silica phase. These ejecta are intimate mixtures of a relatively felsic magma similar to Pleistocene Copahue lavas and a mafic basaltic andesite, with minor contributions of a magma contaminated with silica-rich hydrothermal wallrock material. Two-pyroxene geothermometry indicates crystallization temperatures of 1020 deg - 1045 deg C. Glass inclusions (59-63 percent SiO2) in plagioclase and olivine crystals yield very low volatile contents in the melt (0.4-1.5 percent H2O). The 1995/2000 magmas resided at shallow level and degassed into the active volcano-hydrothermal system which discharges acid fluids into the Copahue crater lake and hot springs. More mafic magma intruded this shallow batch and the mixture rose into the hydrothermal system and assimilated siliceous wall rock. A Ti-diffusion profile in a magnetite crystal suggests that the period between magma mixing and eruption was on the order of 4-10 weeks, and the temperature difference between resident and intruding magma was about 50-60 oC.

  7. National Geochronological Database

    Science.gov (United States)

    Revised by Sloan, Jan; Henry, Christopher D.; Hopkins, Melanie; Ludington, Steve; Original database by Zartman, Robert E.; Bush, Charles A.; Abston, Carl

    2003-01-01

    The National Geochronological Data Base (NGDB) was established by the United States Geological Survey (USGS) to collect and organize published isotopic (also known as radiometric) ages of rocks in the United States. The NGDB (originally known as the Radioactive Age Data Base, RADB) was started in 1974. A committee appointed by the Director of the USGS was given the mission to investigate the feasibility of compiling the published radiometric ages for the United States into a computerized data bank for ready access by the user community. A successful pilot program, which was conducted in 1975 and 1976 for the State of Wyoming, led to a decision to proceed with the compilation of the entire United States. For each dated rock sample reported in published literature, a record containing information on sample location, rock description, analytical data, age, interpretation, and literature citation was constructed and included in the NGDB. The NGDB was originally constructed and maintained on a mainframe computer, and later converted to a Helix Express relational database maintained on an Apple Macintosh desktop computer. The NGDB and a program to search the data files were published and distributed on Compact Disc-Read Only Memory (CD-ROM) in standard ISO 9660 format as USGS Digital Data Series DDS-14 (Zartman and others, 1995). As of May 1994, the NGDB consisted of more than 18,000 records containing over 30,000 individual ages, which is believed to represent approximately one-half the number of ages published for the United States through 1991. Because the organizational unit responsible for maintaining the database was abolished in 1996, and because we wanted to provide the data in more usable formats, we have reformatted the data, checked and edited the information in some records, and provided this online version of the NGDB. This report describes the changes made to the data and formats, and provides instructions for the use of the database in geographic

  8. Sediment unmixing using detrital geochronology

    Science.gov (United States)

    Sharman, Glenn R.; Johnstone, Samuel A.

    2017-11-01

    Sediment mixing within sediment routing systems can exert a strong influence on the preservation of provenance signals that yield insight into the effect of environmental forcing (e.g., tectonism, climate) on the Earth's surface. Here, we discuss two approaches to unmixing detrital geochronologic data in an effort to characterize complex changes in the sedimentary record. First, we summarize 'top-down' mixing, which has been successfully employed in the past to characterize the different fractions of prescribed source distributions ('parents') that characterize a derived sample or set of samples ('daughters'). Second, we propose the use of 'bottom-up' methods, previously used primarily for grain size distributions, to model parent distributions and the abundances of these parents within a set of daughters. We demonstrate the utility of both top-down and bottom-up approaches to unmixing detrital geochronologic data within a well-constrained sediment routing system in central California. Use of a variety of goodness-of-fit metrics in top-down modeling reveals the importance of considering the range of allowable that is well mixed over any single best-fit mixture calculation. Bottom-up modeling of 12 daughter samples from beaches and submarine canyons yields modeled parent distributions that are remarkably similar to those expected from the geologic context of the sediment-routing system. In general, mixture modeling has the potential to supplement more widely applied approaches in comparing detrital geochronologic data by casting differences between samples as differing proportions of geologically meaningful end-member provenance categories.

  9. Sr isotopes at Copahue Volcanic Center, Neuquen, Argentina: Preliminary report

    International Nuclear Information System (INIS)

    Linares, E.; Ostera, H.A.; Cagnoni, M.C

    2001-01-01

    The Copahue Volcanic Center is located in the Cordillera Principal, at 38 L.S., in the Argentina- Chilean border. Detailed geological, geochronological and structural studies were carried out during the last decade (Pesce, 1989; Delpino y Bermudez, 1993; Linares et al., 1995, 1999; Folguera y Ramos, 2000; among others). We present Sr isotopes data on the main units of the Volcanic Center, coupled with a major element geochemistry, to constrain the evolution of the volcanic center (au)

  10. 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

  11. Geochemical, petrological and geochronological observations on the metamorphic rocks of the Tauride belt ophiolites (S. Turkey)

    OpenAIRE

    Celik, Omer Faruk

    2002-01-01

    La chaîne du Taurus (sud de la Turquie) comprend une succession de massifs ophiolitiques. Chacun d'eux possède une semelle métamorphique. Les principales roches constituant ces semelles sont des amphibolites qui se caractérisent, grâce à la géochimie des éléments en traces et des Terres Rares, en basaltes d'îles océaniques, en tholéites d'arcs ou en basaltes de rides. Ces roches sont regroupées par des filons doléritiques et gabbroïques tardifs. L'étude géothermobarométrique montre que ces am...

  12. 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

  13. Geochemical Astro- and Geochronological Constraints on the Early Jurassic

    Science.gov (United States)

    Storm, M.; Condon, D. J.; Ruhl, M.; Jenkyns, H. C.; Hesselbo, S. P.; Al-Suwaidi, A. H.; Percival, L.

    2017-12-01

    The Early Jurassic Hettangian and Sinemurian time scales are poorly defined due to the lack of continuous geochemical records, and the temporal constrain of the Toarcian Oceanic Anoxic Event and associated global carbon cycle perturbation is afflicted by geochemical and biostratigraphical uncertainties of the existing radiometric dates from various volcanic ash bearing sections. Here we present a continuous, orbitally paced Hettangian to Pliensbachian carbon-isotope record of the Mochras drill-core (Cardigan bay Basin, UK). The record generates new insights into the evolution and driving mechanisms of the Early Jurassic carbon cycle, and is contributing to improve the Hettangian and Sinemurian time scale. Furthermore, we introduce a new high-resolution carbon-isotope chemostratigraphy, integrated with ammonite biostratigraphy and new U/Pb single zircon geochronology of the Las Overas section (Neuquén Basin, Argentina). The studied section comprises sediments from the tenuicostatum to Dumortiera Andean Ammonite zone (tenuicostatum to levesqui European standard zones). A stratigraphically expanded negative shift in d13Corg values, from -24‰ down to -32­‰, appears in the tenuicostatum and hoelderi ammonite zone, coeval to the negative excursion in European realm which is associated with the Toarcian Oceanic Anoxic Event. The negative isotope excursion appears concomitant with an increase in sedimentary mercury levels, indicating enhanced volcanic activity. TOC values and elemental data suggest a high sedimentation dilution in the tenuicostatum to pacificum zone. The new geochronological data from several volcanic ash beds throughout the section are further improving the temporal correlation between the Early Toarcian isotope event and causal mechanisms

  14. Geochronology

    International Nuclear Information System (INIS)

    Elworthy, T.P.

    1982-01-01

    As part of the multi-disciplinary research programme to unravel the geological history of the area, radiometric age determinations and isotopic analyses were carried out on intrusive and extrusive rocks from the Ahlmannryggen and Borgmassivet. The intention of the article is to review the radiometric age data so far reported for western Dronning Maud Land, and to construct a preliminary time frame for the geological evolution of this area. Isotope ratios that were determined includes Rb 87 , Sr 86 , Sr 87 , Sr 88 , Ar 39 , Ar 40 and potassium isotopes

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. Argentina; Argentine

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-04-01

    This economical study summarizes the energy situation of Argentina: energy institutions and policy, energy companies (oil, electricity, gas, coal), energy supplies (resources, power production, petroleum, natural gas), prices and tariffs, consumption, economical stakes and perspectives (investments, agreements, projects). Energy data for the 1971-1999 period are summarized in graphs and tables. (J.S.)

  20. Geochemical fingerprints and pebbles zircon geochronology

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 125; Issue 7. Geochemical fingerprints and pebbles zircon geochronology: Implications for the provenance and tectonic setting of Lower Cretaceous sediments in the Zhucheng Basin (Jiaodong peninsula, North China). Jin-Long Ni Jun-Lai Liu Xiao-Ling Tang ...

  1. Chronostratigraphy and geochronology: A proposed realignment

    NARCIS (Netherlands)

    Zalasiewicz, J.; Cita, M.B.; Hilgen, F.; Pratt, B.R.; Strasser, A.; Thierry, J.; Weissert, H.

    2013-01-01

    We propose a realignment of the terms geochronology and chronostratigraphy that brings them broadly into line with current use, while simultaneously resolving the debate over whether the Geological Time Scale should have a “single” or “dual” hierarchy of units: Both parallel sets of units are

  2. 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.

  3. Geochronology of the Jequie-Itabuna granulitic belt and of the Contendas-Mirante volcano-sedimentary belt

    International Nuclear Information System (INIS)

    Marinho, Moacyr M.; Barbosa, Johildo S.F.; Sabate, Pierre

    1995-01-01

    The Jequie-Itabuna Granulitic Belt is divided here into the Jequie-Mutuipe-Maracas Domain and the Atlantic Coast Domain. The paper analyzes the geochronological data from the Jequie-Mutuipe-Maracas Domain in two parts: plutonic rocks equilibrated in granulite facies, including the charno-enderbitic rocks from the Laje-Mutuipe region and the charnockitic rocks from the Maracas region; and ortho- and paraderived rocks metamorphosed in granulite facies, with the data obtained from rocks collected at the Jequie quarry and from homogeneous rocks collected at the western outskirts of the Jequirica town. The available geochronological data for the Atlantic Coast Domain is discussed, and due to the lack of petrologic control of the analyzed rocks, the geological significance of the ages between 2.0 and 2.3 is obtained in several line regressions. The paper identifies the following domains within the Contendas-Mirante volcano-sedimentary belt: the the basement dones, the volcano-sedimentary sequence and the intrusive rocks. The basement domes is the domain of the ancient gray gneisses (ca 3.4 Ga), to TTG (tonalite-trondhjemite-granodiorite) terrains and among the different massifs that crop out in the SE sector of the volcano-sedimentary belt, those of Sete Voltas and Boa Vista/Mata Verde have geochronological data available. The volcano-sedimentary sequence is divided into a lower, a middle and an upper unit and its available isotopic data are analyzed. The item referent to the intrusive rocks deals with the following plutons: The Lagoa Morro da Velha granitoid, the Pe da Serra granite, the Rio Jacare sill and the Transamazonian granites. 31 figs., 5 tabs

  4. 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

  5. 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.

  6. Geochemistry and zircon U-Pb geochronology of the Pulang complex, Yunnan province, China

    International Nuclear Information System (INIS)

    Pang, Zhenshan; Du, Yangsong; Cao, Yi; Gao, Fuping; Wang, Gongwen; Dong, Qian

    2014-01-01

    The Pulang complex is located tectonically at the southern margin of the Yidun-Zhongdian island arc belt in Yunnan province, China, and is closely related to formation of the Pulang copper deposit, which is the largest copper deposit in Asia. The Pulang complex can be divided into three intrusion stages based on contact relationships and petrological characteristics: (1) a first stage of quartz dioritic porphyry; (2) a second stage of quartz monzonitic porphyry; and (3) a third stage of granodioritic porphyry. The crystallization ages of these intrusion stages were determined by single-zircon U-Pb dating, yielding ages of 221.0 ± 1.0, 211.8 ± 0.5, and 206.3 ± 0.7 Ma for the first, second, and third stages, respectively. These dates, integrated with previous geochronological data and field investigations, indicate that the second-stage quartz monzonitic porphyry has a close spatial and temporal relationship with the large Pulang porphyry copper deposit. These age data, geochemical and Sr-Nd isotopic results suggest that the Pulang complex formed in the Indo-Chinese epoch (257∼ 205 Ma) by multiphase intrusion of a mixture of mantle- and crust-derived magmas. (author)

  7. Geochronologic inventory of Rio de Janeiro State

    International Nuclear Information System (INIS)

    Fonseca, A.C.

    1995-01-01

    This paper presents a geochronological study on the Rio de Janeiro State rocks, Southeast Brazil. It is based in a great volume of analytical results (Rb-Sr, U-Pb, Sm-Nd, K-Ar, Ar-Ar and fission tracks dating). It also evocates a little doubt on the Juiz de Fora Complex age: a transamazonic age and some doubts on the sedimentation age of Paraiba do Sul and Andrelandia groups, Costeiro Complex and the existence of a correlation between these litho-stratigraphic units. 19 refs., 2 tabs

  8. Fission track geochronology of Eastern Ghats

    Energy Technology Data Exchange (ETDEWEB)

    Virk, H S; Koul, S L; Singh, S [Punjabi Univ., Patiala (India). Dept. of Physics

    1978-12-01

    Fission track geochronology of Eastern Ghats has been established by using fission track technique in dating micaceous and accessory minerals occurring in the region. Annealing studies confirm that radiation damage fossil tracks can be erased in minerals under intense metamorphic episodes thus resetting the geological clock. The fission track ages of the minerals range between 450 +- 5 m.y. to 622 +- 148 m.y. It is concluded that f.t. ages of the minerals date the last metamorphic event of the Eastern Ghats, known as the Indian Ocean Cycle.

  9. Petrology, geochemistry, and geochronology of the Chah-Bazargan gabbroic intrusions in the south Sanandaj-Sirjan zone, Neyriz, Iran

    Science.gov (United States)

    Fazlnia, Abdolnaser; Schenk, Volker; Appel, Peter; Alizade, Abouzar

    2013-07-01

    The Chah-Bazargan gabbroic intrusions are located in the south of Sanandaj-Sirjan zone. Precise U-Pb zircon SHRIMP ages of the intrusions show magmatic ages of 170.5 ± 1.9 Ma. These intrusions consist primarily of gabbros, interspersed with lenticular bodies of anorthosite, troctolite, clinopyroxenite, and wehrlite. The lenticular bodies show gradational or sharp boundaries with the gabbros. In the gradational boundaries, gabbros are mineralogically transformed into anorthosites, wehrlites, and/or clinopyroxenites. On the other hand, where the boundaries are sharp, the mineral assemblages change abruptly. There is no obvious deformation in the intrusions. Hence, the changes in mineral compositions are interpreted as the result of crystallization processes, such as fractionation in the magma chamber. Rock types with sharp boundaries show abrupt chemical changes, but the changes exhibit the same patterns of increasing and decreasing elements, especially of rare earth elements, as the gradational boundaries. Therefore, it is possible that all parts of the intrusions were formed from the same parental magma. Parts showing signs of nonequilibrium crystallization, such as cumulate features and sub-solidification, underwent fracturing and were interspersed throughout the magma chamber by late injection pulses or mechanical movements under mush conditions. The geological and age data show that the intrusions were formed from an Al-, Sr-, Fe-enriched and K-, Nb-depleted tholeiitic magma. The magma resulted from the partial melting of a metasomatized spinel demonstrated by negative Nb, P, Hf, and Ti, and positive Ba, Sr, and U anomalies typical of subduction-related magmas.

  10. An Integrated Geochronological, Petrological, Geochemical and Paleomagnetic Study of Paleoproterozoic and Mesoproterozoic Mafic Dyke Swarms in the Nain Craton, Labrador

    Science.gov (United States)

    Sahin, Tugce

    The Nain craton comprises the western, Labrador segment of the larger North Atlantic craton (NAC) which exposes Early through Late Archean gneisses. The NAC is bounded on all sides by Paleoproterozoic collisional orogens that involved either considerable structural reworking (Torngat-Nagssugtoqidian-Lewisian) or the accretion of juvenile arc magmas (Ketilidian-Makkovik). The NAC remains poorly understood compared to other Archean crustal blocks now dispersed globally. Compounding this problem is a lack of reliable paleomagnetic poles for NAC units that predate its assembly into the supercontinent Laurentia by ca. 1800 Ma, which could be used to test neighboring relationships with other cratonic fragments. In order to understand the history of the NAC as part of a possible, larger supercontinent, the record of mafic dyke swarms affecting the craton, particularly those that postdate the Late Archean terrane assembly, were examined in this study. Diabase or gabbroic dyke swarms are invaluable in such studies because their geometries offer possible locus points, they often have a punctuated emplacement and precisely datable crystallization histories, and they have cooling histories and oxide mineralogy amenable to recovering robust paleopoles. Coastal Labrador exposes a number of mafic dykes, some of which are demonstrably Paleoproterozoic (e.g. 2235 Ma Kikkertavak dykes; 2121 Ma Tikkigatsiagak dykes) or Mesoproterozoic (e.g. 1280-1270 Ma Nain and Harp dykes) in age (U-Pb; baddeleyite or zircon). The southern half of the Nain craton (Hopedale block) in particular preserves a rich array of mafic dykes. Dyke cross-cutting relationships are numerous and relatively well exposed, permitting multiple opportunities for paleomagnetic field tests (e.g. baked contact). The results presented here allow understanding of the tectonic evolution of the NAC with implications for strengthened Labrador-Greenland correlations, and testing possible Paleoproterozoic supercontinent reconstructions.

  11. Petrology, thermobarometry and geochronology of Yelapa Complex: Implications in the tectonic history of the basement of Puerto Vallarta Batholith, Mexico

    Science.gov (United States)

    Gutiérrez Aguilar, F.; Schaaf, P. E. G.; Hernandez-Trevino, T.; Solis-Pichardo, G.; Vite-Sánchez, O.

    2017-12-01

    The Yelapa Complex (YC) is localizated in the north, central and western of Cabo Corrientes in Jalisco, México. Is constituted by metasedimentary, metaigneous and migmatites which are intruded by deformed plutons. The YC are part of the Puerto Vallarta Batholith a body of 9000 km2 exposed at the mid-western part of the Mexican Pacific margin. The para-gneis of YC in the region of Chimo, present a mineral assemblage of Sil + Bt + Pl ± Grt ± Fsp ± Ilm. The orto-gneis in the región of Cabo Corrientes are constituted by Pl + Amp ± Qz ± Ap ± Zrn. Phase equilibria modelling of two paragneis yield peak conditions of 7-8 kbar and 650-700ºC. The patterns of REE of the studied rocks suggest: 1) Enrichment of LREE and flat patterns in HREE with respect to chondrite and; 2) Negative Eu anomaly in all samples analyzed suggesting plagioclase fractionation. On the other hand, the study of individual zircons using LA-ICP-MS from 3 para-gneis and 1 orto-gneis yield following information: 1) A máximum depositional age of 223 Ma, which also show abundant zircón populations with ages between 241-273 Ma for para-gneis and 2) The protolith age crystallization of 127 Ma for orto-gneis. The results along with new Sr-Nd isotopic data from whole rock and Rb-Sr in micas, suggest a tectonic evolution for the Yelapa Complex as a transition from a passive continental margin regime ( 223-273 Ma) to a continental arc setting ( 127). Thus, regional metamorphism and multiple magmatic episodes were associated to the convergence of the Farallon and North America plates during the Middle Jurassic to the Late Cretaceous.

  12. Geochronology and petrology of OIB-type lavas from the central part of the Mexican Volcanic Belt

    International Nuclear Information System (INIS)

    Hasenaka, Toshiaki; Yoshida, Takeyoshi; Uto, Kozo; Uchiumi, Shigeru

    1995-01-01

    In Mexican Volcanic Belt, typical continental margin arc volcanic activities have occurred accompanying the subduction of Rivera Plate and Cocos Plate into North American Plate. It has been known by recent geochemical research that the oceanic island type magma which does not show the characteristic chemical composition of subduction zone has extruded. In order to investigate the relation of the development of volcanic belt in continental margin are with the change of wide area tectonics, and to impose important limit on magma formation models, it is important to know the state of production of oceanic island type magma in continental margin arc and the age of its activities. In this report, the results of the K-Ar age measurement for the oceanic island type lava produced in the middle of Mexican Volcanic Belt are shown, and the geochemical features of those samples are clarified. The state of production and the petrography of oceanic island type igneous rock samples are explained. The K-Ar age measurement experiment and the results are reported. The chemical composition of oceanic island type lava determined by photon activation process and fluorescent X-ray analysis is shown. (K.I.)

  13. 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

  14. 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

  15. 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

  16. 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.

  17. Medical revolution in Argentina.

    Science.gov (United States)

    Ballarin, V L; Isoardi, R A

    2010-01-01

    The paper discusses the major Argentineans contributors, medical physicists and scientists, in medical imaging and the development of medical imaging in Argentina. The following are presented: history of medical imaging in Argentina: the pioneers; medical imaging and medical revolution; nuclear medicine imaging; ultrasound imaging; and mathematics, physics, and electronics in medical image research: a multidisciplinary endeavor.

  18. Argentina's nuclear red herring

    International Nuclear Information System (INIS)

    Perera, J.

    1983-01-01

    The article deals with Argentina's nuclear power programme over the last 30 years, including the country's efforts to be nuclear independent of the United States, as well as its aspirations to be a nuclear supplier to latin America. The latter policy on economic, rather than military grounds for nuclear weapons, has led to Argentina's decision to build a uranian enrichment plant. (U.K.)

  19. 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.

  20. 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

  1. High-precision ID-TIMS zircon U-Pb geochronology using new 1013 Ohm resistors

    Science.gov (United States)

    Von Quadt, A.; Buret, Y.; Large, S.; Peytcheva, I.; Trinquier, A.; Wotzlaw, J. F.

    2015-12-01

    Faraday cups equipped with high gain amplifiers provide a means to measure small ion beams in static mode without the limited linear range of ion counting systems. We tested the application of newly available 1013 Ohm resistors to ID-TIMS zircon U-Pb geochronology using a range of natural and synthetic reference materials. The TritonPlus-RPQ at the Institute of Geochemistry and Petrology, ETH Zurich, is equipped with five new 1013 Ohm resistors and one MasCom secondary electron multiplier, allowing to measure the 202-204-205-206-207-208Pb masses in static mode. U is measured subsequently as U-oxide (265-267-270UO2) during a second step, also in static Faraday mode. The gain calibration of the 1013 Ohm resistors was performed using the procedure of Trinquier (2014), with 144Nd-146Nd being measured using 1011 Ohm resistor and 142-143-145-148-150Nd being measured using 1013 Ohm resitors (Trinquier, 2014; Koornneef et al., 2014). Standard deviations of the noise in all five new 1013 Ohm resistors are lower than 5.0 x 10-6 over a 6 month period, with no shift occurring over this time interval. This new detector set-up was tested by analyzing natural zircon standard materials and synthetic U/Pb solutions (www.earthime.org), ranging in age from ~2 Ma to ~600 Ma. All natural zircon standards were chemically abraded (Mattinson, 2005) and all samples were spiked with the ET2535 tracer solution. U-Pb dates obtained using the static measurement routine are compared to measurements employing dynamic peak jumping routines on the MasCom multiplier. This study illustrates the benefits and current limitations of using high gain amplifiers to measure small ion beams for zircon U-Pb geochronology compared to conventional dynamic ion counting techniques. Mattinson, J.M. (2005) Chemical Geology 220:47-66; Trinquier, A. (2014) Application Note 30281; Koornneef, J. et al (2014) Analytica Chimica Acta 819:49-55.

  2. 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

  3. EARTHTIME: Teaching geochronology to high school students

    Science.gov (United States)

    Bookhagen, Britta; Buchwaldt, Robert; McLean, Noah; Rioux, Matthew; Bowring, Samuel

    2010-05-01

    The authors taught an educational module developed as part of the EARTHTIME (www.earth-time.org) outreach initiative to 215 high school students from a Massachusetts (USA) High School as part of an "out-of-school" field trip. The workshop focuses on uranium-lead (U-Pb) dating of zircons and its application to solving a geological problem. The theme of our 2.5-hour module is the timing of the K-T boundary and a discussion of how geochronology can be used to evaluate the two main hypotheses for the cause of the concurrent extinction—the Chicxlub impact and the massive eruption of the Deccan Traps. Activities are divided into three parts: In the first part, the instructors lead hands-on activities demonstrating how rock samples are processed to isolate minerals by their physical properties. Students use different techniques, such as magnetic separation, density separation using non-toxic heavy liquids, and mineral identification with a microscope. We cover all the steps from sampling an outcrop to determining a final age. Students also discuss geologic features relevant to the K-T boundary problem and get the chance to examine basalts, impact melts and meteorites. In the second part, we use a curriculum developed for and available on the EARTHTIME website (http://www.earth-time.org/Lesson_Plan.pdf). The curriculum teaches the science behind uranium-lead dating using tables, graphs, and a geochronology kit. In this module, the students start by exploring the concepts of half-life and exponential decay and graphically solving the isotopic decay equation. Manipulating groups of double-sided chips labeled with U and Pb isotopes reinforces the concept that an age determination depends on the Pb/U ratio, not the absolute number of atoms present. Next, the technique's accuracy despite loss of parent and daughter atoms during analysis, as well as the use of isotopic ratios rather than absolute abundances, is explained with an activity on isotope dilution. Here the students

  4. Building Interactive Visualizations for Geochronological Data

    Science.gov (United States)

    Zeringue, J.; Bowring, J. F.; McLean, N. M.; Pastor, F.

    2014-12-01

    Since the early 1990s, Ken Ludwig's Isoplot software has been the tool of choice for visualization and analysis of isotopic data used for geochronology. The software is an add-in to Microsoft Excel that allows users to generate visual representations of data. However, recent changes to Excel have made Isoplot more difficult to use and maintain, and the software is no longer supported. In the last several years, the Cyber Infrastructure Research and Development Lab for the Earth Sciences (CIRDLES), at the College of Charleston, has worked collaboratively with geochronologists to develop U-Pb_Redux, a software product that provides some of Isoplot's functionality for U-Pb geochronology. However, the community needs a full and complete Isoplot replacement that is open source, platform independent, and not dependent on proprietary software. This temporary lapse in tooling also presents a tremendous opportunity for scientific computing in the earth sciences. When Isoplot was written for Excel, it gained much of the platform's flexibility and power but also was burdened with its limitations. For example, Isoplot could not be used outside of Excel, could not be cross-platform (so long as Excel wasn't), could not be embedded in other applications, and only static images could be produced. Nonetheless this software was and still is a powerful tool that has served the community for more than two decades and the trade-offs were more than acceptable. In 2014, we seek to gain flexibility not available with Excel. We propose that the next generation of charting software be reusable, platform-agnostic, and interactive. This new software should allow scientists to easily explore—not just passively view—their data. Beginning in the fall of 2013, researchers at CIRDLES began planning for and prototyping a 21st-century replacement for Isoplot, which we call Topsoil, an anagram of Isoplot. This work is being conducted in the public domain at https://github.com/CIRDLES/topsoil. We

  5. Geochronologic constraints of the uplift and metamorphism along the Alpine Fault, South Island, New Zealand

    International Nuclear Information System (INIS)

    Chamberlain, C.P.; Zeitler, P.K.; Cooper, A.F.

    1995-01-01

    Geochronological studies of pegmatites and Alpine Schist exposed east of the Alpine Fault, South Island, New Zealand, reveal a complex history beginning with magmatism and metamorphism at c. 68 m.y. ago and ending with rapid uplift and exhumation in the last 5 m.y. Pegmatites exposed in the Mataketake Range give conventional U-Pb monazite and SHRIMP ion-probe zircon ages of 68 ± 2.6 Ma and 67.9 ± 2.5 Ma, respectively. Inasmuch as petrologic and isotopic data indicate that the Alpine pegmatites are melts derived from the Alpine Schist, the age of the pegmatites suggests that, at least locally, the high-grade metamorphism is considerably younger than previously assumed. We tentatively suggest that metamorphism, in at least some areas of the Alpine Schist, may be associated with Late Cretaceous transtension rather than resulting from the consequences of collision during the Rangitata Orogeny. 40 Ar/ 39 Ar studies of hornblendes from the Alpine Schist, collected from the Haast River to the Franz Josef Glacier area, reveal highly disturbed spectra. Despite this complexity, these analyses define a systematic decrease in ages both across-strike toward the Alpine Fault (Haast River traverse) and northwards along-strike towards Mt Cook. This pattern of decreasing 40 Ar/ 39 Ar hornblende ages is also observed in lower closure temperature systems such as zircon and apatite fission-track ages. We interpret the decrease in ages toward the fault to be the result of deeper exhumation in the immediate vicinity of the Alpine Fault, whereas we interpret the northward younging of fault-proximal samples to be a result of both more recent and possibly more extensive exhumation than occurred in areas to the south. (author). 55 refs., 4 figs., 2 tabs

  6. Brief review on and prospect of the development of geochronology

    International Nuclear Information System (INIS)

    Chen Xuanhua; Dong Shuwen; Liu Dunyi; Ding Tiping; Shi Jing

    2003-01-01

    Geochronology is an important fundamental branch of modern geology, which was coming into being in the early 20 century and got rapid development in 1950s and 1960s. The common used and newly developed geochronological methods, such as U-Pb, Sm-Nd, Rb-Sr, Lu-Hf, 40 Ar/ 39 Ar, Fission Track, (U-Th)/He, TIMS U-series, cosmogenetic nuclides (including 14 C, etc.) and CFC and 3 H/ 3 He for young groundwater dating, are generally discussed in this paper on their some aspects of application and thermochronology. Through the statistics of geology and geochronological documents based on GeoRef and GDS data-base, we prospect that the geochronology in the international geologic society will get more and more important status in the near future, and suggest that the geologists in China may not neglect this kind of tendency. According to the using of geochronological methods in three GSA journals, we consider the U-Pb, 40 Ar/ 39 Ar and 14 C as the mostly used and reliable geochronometers in recent years. Also, it is recognized in this paper that thermochronology may have good future for low temperature history during mountain range exhumation and geomorphic formation, and young geological body such as ground water. (authors)

  7. 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)

  8. 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

  9. LDC nuclear power: Argentina

    International Nuclear Information System (INIS)

    Tweedale, D.L.

    1982-01-01

    Argentina's 31-year-old nuclear research and power program makes it a Third World leader and the preeminent Latin American country. Easily accessible uranium fuels the heavy water reactor, Atucha I, which provides 10% of the country's electric power. Atucha II and III are under construction. Several domestic and international factors combined to make Argentina's program succeed, but achieving fuel-cycle independence and the capacity to divert fissionable material to military uses is a cause for some concern. 60 references

  10. Cenomanian-? early Turonian minimum age of the Chubut Group, Argentina: SHRIMP U-Pb geochronology

    Science.gov (United States)

    Suárez, Manuel; Márquez, Marcelo; De La Cruz, Rita; Navarrete, César; Fanning, Mark

    2014-03-01

    Four new SHRIMP U-Pb zircon ages older than 93 Ma from samples of the two uppermost formations accumulated in two different depocenters (Golfo de San Jorge and Cañadón Asfalto basins) of the Chubut Group in central Argentinean Patagonia, establish a pre-late Cenomanian-? early Turonian age for the group. It also confirms a coeval and comparable evolution of the two depocenters, where distal pyroclastic material was deposited together with fluvial and lacustrine facies.

  11. Detrital zircon geochronology and provenance of the Chubut Group in the northeast of Patagonia, Argentina

    Science.gov (United States)

    Navarro, Edgardo L.; Astini, Ricardo A.; Belousova, Elena; Guler, M. Verónica; Gehrels, George

    2015-11-01

    The Chubut Group constitutes the most widespread sedimentary unit in NE Patagonia, characterized by variable-energy fluvial deposits. U-Pb analysis of detrital zircons from two sections of the Chubut Group constraint the age of the oldest sedimentary rocks in the northeast of the Somuncurá - Cañadón Asfalto Basin. In the Cañadón Williams area, at San Jorge section, 20 km NW of Telsen locality, dating of 56 detrital zircons from a medium to coarse sandstone indicated a maximum depositional age of 109 ± 1 Ma (n = 4). These sandstones were interpreted to represent shallow channels, associated with a lacustrine system. In the Telsen locality, a laser ablation analysis of 115 detrital zircons from a medium to coarse-grained sandstone, from fluvial channel facies, yielded a maximum depositional age of ca. 106 ± 1 Ma (n = 8). Both ages are consistent with volcanic events of the Barremian to Albian age in the central Patagonian Andes Region. Cathodoluminescence images of zircons from the San Jorge sample suggest an igneous origin, which is further supported by Th/U values above 0.5 in most of the grains. The distribution of the statistical modes of the main age populations of detrital zircons for the two samples [182, 185 and 189 Ma for Telsen sample (T2S) and 181 ± 1 Ma for San Jorge sample (SJS)] matches the age of the volcanic Marifil Formation. The rocks of the Marifil Formation of these ages are exposed NE to SE of the study area. The abundance of zircons of similar Jurassic ages (n = 52 for SJS and n = 105 for T2S) and the external morphology of the zircons in the sample SJS, implies a close proximity of the source area. Suggestion that the Marifil Formation was the main provenance source is also supported by northeast-southeasterly paleocurrents measured at the San Jorge and Telsen sections.

  12. 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

  13. Introduction to isotopic geochronology of pre-quaternary age

    International Nuclear Information System (INIS)

    Poupeau, G.

    1985-01-01

    The historical development of Geochronology is summarized, showing its strong relation to Physics. Considerations about radioactivity and its application to radiochronology are made, including the use of U, Th-Pb dating techniques. A vast list of bibliographical references is given for further consultation. (C.L.B.) [pt

  14. Helosis (Balanophoraceae en Argentina Helosis (Balanophoraceae in Argentina

    Directory of Open Access Journals (Sweden)

    José Luis Fontana

    2006-07-01

    Full Text Available Se cita por primera vez para Argentina Helosis cayennensis (Swartz Sprengel var. cayennensis en base a colecciones hechas por los autores en la Isla argentina de Apipé Grande, Ituzaingó, provincia de Corrientes. Se describe e ilustra la especie, el desarrollo de la planta y su estado de conservación. Esta cita de Helosis corresponde a un género nuevo para la flora argentina.Helosis cayennensis var. cayennensis is reported for the first time for Argentina. The species is described and ilustrated. Developement and ecology are also given. Helosis is also a new generic record for Argentina.

  15. 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.

  16. 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)

  17. Economy Profile of Argentina

    OpenAIRE

    World Bank Group

    2017-01-01

    Doing Business 2018 is the 15th in a series of annual reports investigating the regulations that enhance business activity and those that constrain it. This economy profile presents the Doing Business indicators for Argentina. Doing Business presents quantitative indicators on business regulation and the protection of property rights that can be compared across 190 economies; for 2018 Arge...

  18. Radiation vulcanization in Argentina

    International Nuclear Information System (INIS)

    Ferenaz, Guillermo W.; Smolko, Eduardo E.

    1999-01-01

    The possibilities of using in Argentina the radiation process to vulcanize natural latex are analyzed. Experimental studies to define the irradiation conditions have been carried out and the preliminary elaboration of an irradiation device that includes the chemical reactor has been started. (author)

  19. El IDRC en Argentina

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

    comercio capaces de sostener el crecimiento y reducir la pobreza. ... Rosario, en Argentina, se ha convertido en un ejemplo internacional para la agricultura urbana gracias a la ... para evaluar los riesgos y beneficios de esta tecnología para ...

  20. 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.

  1. 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)

  2. 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)

  3. Pre-cambrian geochronology in Rio Grande do Norte, Brazil

    International Nuclear Information System (INIS)

    Galindo, A.C.

    1981-08-01

    The Precambrian region polyciclic caracter, in the Rio Grande do Norte State has make difficulties to its geochronological and geological studies. Four importants tectonometamorphic occurences identified dissimulate the original isotopic composition of the rocks. Is much defined the presence of three geochronological events wich left vestiges in the differents Serido litological units. The first event is related with Jequie cicle (2,7 b.y) and related with the Caico Group rocks. The second important event define the Transamazonic cicle (2.1 b.y). The third is correlated with Brazilian Cicle, when occurred the granitoids and pegmatites bodies formation. This third event was the last in this region and affect the other units too. (C.D.G.) [pt

  4. Fennoscandia in the Phanerozoic: Paleogeodynamic Reconstructions Based on the New Paleomagnetic and Geochronological Data from the Kola Magmatic Province (kola Peninsula, Russia)

    Science.gov (United States)

    Veselovskiy, R. V.; Arzamastsev, A. A.

    2013-12-01

    During last four years we studied more than 100 dolerite and alkaline dykes, which are widely spread on the Kola Peninsula and belong to the Devonian magmatic province. Within the scope of our researches some of these dykes have been dated and their precise isotopic ages (Ar/Ar, Sm-Nd, Rb-Sr) lie in the range of 390-360 Ma (Veselovskiy et al., 2013). The age of other sampled dykes can be considered as Devonian due to similarity of their paleomagnetic, geochemical and petrological characteristics to the dated ones. Paleomagnetic directions have been obtained from more than 80 dykes. Almost all dykes yielded (a) a low-temperature component that is aligned along the present-day field and is likely of viscous origin; (b) a well defined dual-polarity intermediate-temperature component with steep eastward directions that accounts for a main part of the NRM and often decays to the origin on orthogonal plots; and (c) a dual-polarity high-temperature component with shallow inclinations and ENE declinations of presumed primary origin. The presence of the primary high-temperature component makes us possible to calculate preliminary Baltica's paleomagnetic pole for the Middle-Late Devonian. In view of the obtained microprobe data we believe that intermediate component is a result of unknown hydrothermal process, which age can be estimated from the comparison of corresponding paleomagnetic pole with the Baltica's APWP as Jurassic. We believe that both mentioned episodes of endogenous activity within the large stable craton were connected with plume-lithospheric interaction in the Devonian and Jurassic. In this presentation we use the obtained paleomagnetic, petrological and geochronological data to determine the paleogeography of Baltica in the Devonian and Jurassic times and to find its position within the global paleotectonic and geodynamic reconstructions. This study was funded by grants RFBR # 12-05-00216, 13-05-12021, 13-05-12030 and grant MK-3383.2012.5.

  5. Geochronological constraints on the evolution of El Hierro (Canary Islands)

    Science.gov (United States)

    Becerril, Laura; Ubide, Teresa; Sudo, Masafumi; Martí, Joan; Galindo, Inés; Galé, Carlos; Morales, Jose María; Yepes, Jorge; Lago, Marceliano

    2016-01-01

    New age data have been obtained to time constrain the recent Quaternary volcanism of El Hierro (Canary Islands) and to estimate its recurrence rate. We have carried out 40Ar/39Ar geochronology on samples spanning the entire volcanostratigraphic sequence of the island and 14C geochronology on the most recent eruption on the northeast rift of the island: 2280 ± 30 yr BP. We combine the new absolute data with a revision of published ages onshore, some of which were identified through geomorphological criteria (relative data). We present a revised and updated chronology of volcanism for the last 33 ka that we use to estimate the maximum eruptive recurrence of the island. The number of events per year determined is 9.7 × 10-4 for the emerged part of the island, which means that, as a minimum, one eruption has occurred approximately every 1000 years. This highlights the need of more geochronological data to better constrain the eruptive recurrence of El Hierro.

  6. Rb-Sr geochronology of leucocratic granitoid rocks from the Spissko-Gemerske Rudohorie Mts. and Veporicum

    International Nuclear Information System (INIS)

    Cambel, B.; Veselsky, J.

    1989-01-01

    Information is given on new Rb-Sr data from leucocratic types of rocks occurring in the Gemericum and Veporicum. Basses on isochron geochronological data, mutual geochronological and geochemical relations are discussed. (author). 3 figs., 47 tabs., 14 refs

  7. Western cratonic domains in Uruguay, geochronology

    International Nuclear Information System (INIS)

    Preciozzi, F; Pell, E; Muzio, R; Ledesma, J.J; Guerequiz, R

    2001-01-01

    of this unit is also illustrated by the existence of extended mylonitic zones, relicts of supracrustal rocks and granitic intrusions with different ages and compositions. Some isochronic ages (Rb/Sr WR) are ca. 650 to 500 Ma, being associated to partial melting processes generated during the Neoproterozoic orogeneses. The most important and the oldest metamorphic event yields transamazonic ages around 2250 ± 60 Ma in granulitic orthogneisses of Rivera using Rb/Sr (WR) (Cordani and Soliani, 1990). These rocks are intercalated with leucocratic and cataclastic gneisses and with diverse types of mafic rocks (amphibolites, piroxenites and peridotites). A rapakivi granite dated in 1.75 Ga is located near the town Minas de Corrales. Another one having a Rb/Sr isochronic age of 1760 ± 32 Ma (Bossi and Campal, 1992) is developed to the south and it is called Illescas Batholith (Campal and Schipilov, 1995). Recent geochronologic ages using Shrimp U/Pb (Hartmann et al., 2000) in samples taken from the Valentines Block produced ages around 2.6 Ga for crystallization and around 2.2 Ga for metamorphism. Pavas Block is composed of an orthogneissic basement and a volcano-sedimentary cover strongly deformed and recristalized, occurring like an allocton tectonic sheet. A K/Ar determination in muscovite gave an age of 584.9 ± 18 Ma and using Rb/Sr (WR) systematics the age obtained was 1252 ± 3 Ma with R0 = 0.72664. Metasedimentary zircons gave ages of 3.4 Ga, which is interpreted as the age of crystallization, and of 2.7 Ga, which is interpreted as the age of metamorphism. Younger ages for this terrane were not observed. In basement rocks of de la China creek Hartmann (2000) obtained an age of 3.41 Ga in addition to events at 3.1 Ga and 2.7 Ga. Pavas Block does not record events later than 2.7 Ga except for values around 586 Ma using K/Ar method in green muscovites taken from corundum micaceous quartzites (au)

  8. Argentina set for privatization

    International Nuclear Information System (INIS)

    Chynoweth, E.

    1992-01-01

    Buyers are lining up for Argentina's two big state-controlled petrochemical groups, Buenos Aires-based Petroquimica General Mosconi (PGM) and Petroquimica Bahia Blance (PBB). However, feedstock supply contracts with government-owned oil group Yacientos Petroliferos Fiscales (YPG) and gas group Gas del Estado hold the key to both sales. Shell Compania Argentina Petroleo SA (CAPSA), Perez Companc, and Global Petroleum have already bought PGM tender documentation. Shell says it will bid for PGM if the feedstock contract with YPF is acceptable. In addition to price and volume, Shell says the length is critical; it wants a 15-year deal, but would settle for 11. YPF initially sought a five-year contract. PGM, which produces 300,000 m.t./year of aromatics, plus oxo alcohols, methanol, and methyl tert-butyl ether, has sales of $150 million/year

  9. Crisis cambiaria en Argentina

    OpenAIRE

    Féliz, Mariano

    2009-01-01

    El análisis de la articulación entre el proceso de valorización exitosa de capital y la tendencia a la desvalorización de las mercancías se aplica a una de las manifestaciones de la crisis argentina: la devaluación del peso. Se estudia la relación entre la determinación del tipo de cambio y la valorización del capital. Se discuten las tendencias concretas de la economía argentina en la década de 1990 y se muestra cómo la devaluación de 2001-2002 fue producto necesario del propio proceso de va...

  10. 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.

  11. Fruit fly eradication: Argentina

    International Nuclear Information System (INIS)

    2003-01-01

    Fruit exports account for 9% of Argentina's total agricultural exports and generate annually close to $450 million. This could be increased but for fruit flies that cause damage equivalent to 15% to 20% of present production value of fruit and also deny export access to countries imposing quarantine barriers. The Department of Technical Co-operation is sponsoring a programme, with technical support from the Joint FAO/IAEA Division, to eradicate the Mediterranean fruit fly using the Sterile Insect Technique (SIT). (IAEA)

  12. Argentina [Country report

    International Nuclear Information System (INIS)

    Ferreyra, R.

    2005-01-01

    The airborne geophysical surveys developed in Argentina are described. They have got more than 500.000 km 2 acquiring data for U, Th, K and total background activity. Other types of published data are also mentioned (satellite imagery, seismic hazard, climate, soil distributions, etc.). The availability of maps with the abundances of elements analyzed at the country and also at laboratories from Canada is described, as well as data of analysis of several elements at two study areas proposed at the outset of the project. The availability of process rate data and epidemiological data is also explained. Argentina intended fully to participate in the CRP at the outset of the project. Due, however, to external resource constraints imposed on the participating organization (Comision Nacional de Energia Atomica, CNEA), the level of participation had to be significantly reduced. Nonetheless, in the first period of the CRP, Argentina undertook to collate existing geological and geochemical information within the country, and began to define potential areas for site specific natural systems safety indicator studies. (author)

  13. de la sociedad argentina

    Directory of Open Access Journals (Sweden)

    Diego Galeano

    2007-01-01

    Full Text Available Este artículo trata sobre un período de la historia argentina en el cual la "mirada médica", a través de un grupo de prestigiosos intelectuales, se convirtió en una clave de interpretación de la sociedad argentina. El análisis gira en torno a la obra de uno de los médicos higienistas más influyentes, José María Ramos Mejía, deteniéndose especialmente en su libro más famoso: Las multitudes argentinas (1899. La hipótesis principal que recorre el texto es la siguiente: la medicalización de la sociedad, acentuada luego de las epidemias de cólera y fiebre amarilla de mediados del siglo XIX, ofreció a las elites públicas la posibilidad de construir dominios legítimos de intervención estatal. Intromisiones del Estado en la vida privada que, además de ser algo resistidas por la población, entraban en tensión con los principios teóricos del liberalismo que los propios miembros de la elite defendían.

  14. Geochronologic study of sediments deposition of two lakes from the Rio Negro basin, Amazonas State, Brazil

    International Nuclear Information System (INIS)

    Gomes, Ana Carla F.; Mozeto, Antonio A.; Cazotti, Raul I.; Nascimento Filho, Virgilio F.; Taddei, Maria Helena

    2000-01-01

    Since 1963 the radionuclide 210 Pb became an important tool for dating (geochronology) recent sediments (up to 120 years). In this work the sedimentary geochronology of two lakes from the Negro River Basin was determined, using different radiochemical separation methods for 210 Pb and 226 Ra. (author)

  15. Argentina: a mature urbanization pattern.

    Science.gov (United States)

    Rofman, A B

    1985-02-01

    "This article describes the historical development of Argentina's cities, pointing out the traditional dominance of the 'centre-litoral' region and...[of] Buenos Aires. Recent trends such as the population increase in the southern region are described and demographic trends are related to economic developments. The article concludes by examining Argentina's contemporary urban patterns, including the current low rate of urbanization." excerpt

  16. Argentina's radioactive waste disposal policy

    International Nuclear Information System (INIS)

    Palacios, E.

    1986-01-01

    The Argentina policy for radioactive waste disposal from nuclear facilities is presented. The radioactive wastes are treated and disposed in confinement systems which ensure the isolation of the radionucles for an appropriate period. The safety criteria adopted by Argentina Authorities in case of the release of radioactive materials under normal conditions and in case of accidents are analysed. (M.C.K.) [pt

  17. 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

  18. 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

  19. 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

  20. 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)

  1. RERTR activities in Argentina

    International Nuclear Information System (INIS)

    Adelfang, P.; Alvarez, L.; Pasqualini, E.

    2002-01-01

    The Atomic Energy Commission of Argentina has been an active participant of the RERTR program since 1978. An important milestone of the Argentinean RERTR program was the development and manufacturing at industrial scale of U 3 O 8 dispersed fuel and its subsequent application to the conversion of the RA-3 reactor core to LEU fuel. More recently, our activities were focused on the development of U 3 Si 2 fuel with a density of 4.8 gU/cm 3 and the improvement of the manufacturing process of this type of fuel. The program to qualify CNEA as a supplier U 3 Si 2 dispersed fuels is scheduled to finalize by mid 2003. To hasten this program the main research reactor of Argentina, the RA3, raised its power from 5 MW to 8 Mw in October this year. This is an intermediate step in the program to increase RA-3 power to 10 MW Currently, one of the main objectives is to develop and qualify the technology for the production of high-density LEU fuel elements using U-Mo alloy. An original way to produce U-Mo powder (the HMD process) was developed and its being upgraded to plant scale production. Another significant progress was the development of LEU targets for the production of 99 Mo, in the form of miniplates prepared with dispersed LEU U-Al x . The shipment to USA of 207 MTR spent fuels containing US origin highly enriched uranium, successfully carried out in the end of 2000, is another remarkable achievement of the Argentinean RERTR program. This activity was carried out in the framework of the United States Foreign Research Reactor Spent Nuclear Fuel Acceptance Program. The fuels were fabricated in Argentina and used in the RA-3 reactor from 1968 to 1987. The inventory of the shipped HEU spent fuel consisted in 166 standard assemblies and 41 control assemblies. (author)

  2. Case study - Argentina

    International Nuclear Information System (INIS)

    Diaz, E.

    1986-01-01

    Antecedents and experience of nuclear activities in Argentina; the Atomic Energy Commission (CNEA). First development and research activities. Research reactors and radioisotopes plants. Health physics and safety regulations. - Feasibility studies for the first nuclear power plant. Awarding the first plant CNA I (Atucha I). Relevant data related to the different project stages. Plant performance. - Feasibility study for the second nuclear power plant. Awarding the second plant CNE (Central Nuclear Embalse). Relevant data related to established targets. Differences compared with the first station targets. Local participation. Plant performance. (orig./GL)

  3. 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...

  4. Activities with Argentina

    International Nuclear Information System (INIS)

    1999-01-01

    In 1989, the US Department of Energy (DOE) responded to the need to redirect resources from weapons production to environmental restoration and waste management by establishing the Office of Environmental Management (EM) and delegated to this office the responsibility of cleaning up the US nuclear weapons complex. Now in its eight year, EM's mission has three central facets: (1) to assess, remediate, and monitor contaminated sites and facilities; (2) to store, treat, and dispose of waste from past and current operations; and (3) to develop and implement innovative technologies for environmental cleanup. To this end, EM has established domestic and international cooperative technology development programs, including one with the Republic of Argentina. Cooperating with Argentine scientific institutes and industries meets US cleanup objectives by: (1) identifying and accessing Argentine EM-related technologies, thereby leveraging investments and providing cost-savings; (2) improving access to technical information, scientific expertise, and technologies applicable to EM needs; and (3) fostering the development of innovative environmental technologies by increasing US private sector opportunities in Argentina in EM-related areas

  5. QUBIC in Argentina

    Science.gov (United States)

    García, B.; Harari, D.; Etchegoyen, A.; Medina, M. C.; Romero, G. E.; Qubic Collaboration

    2017-10-01

    QUBIC (QU Bolometric Interferometer for Cosmology) is an experimental cosmology project to measure the modes in the polarization of the cosmic background radiation (CBR), the fossil relic that reveals the properties at the Universe 380,000 years after the Planck Era. Discovery of the CBR in 1964 and measurement of tiny temperature anisotropies in 1992 were major breakthroughs in our understanding of the Universe. The next challenge is to measure the polarization of the CBR accurately enough to detect modes that would reveal the existence of primordial gravitational waves produced in the first stages of the Planck Era and probe inflation theory, that assumes an accelerated expansion during the first seconds. The mode signal is however extremely weak and its measurement requires complex instruments. The QUBIC collaboration has developed the concept of interferometric bolometry, that brings together the sensitivity of bolometric detectors with the control of systematic effects provided by interferometry. QUBIC is an international collaboration involving several universities and laboratories in France, Italy, United Kingdom and USA. Recently, Argentina has suggested Alto Chorrillo (Salta), as candidate site for the installation of the experiment, next to the LLAMA site. Here we describe the scientific objectives and the main features of the experiment and we detail the process through which the international collaboration decided to install in Argentina its first module as well as the challenges for our country in this project.

  6. RERTR activities in Argentina

    International Nuclear Information System (INIS)

    Adelfang, P.; Alvarez, L.; Boero, N.; Calabrese, R.; De La Fuente, M.; Echenique, P.; Markiewicz, M.; Pasqualini, E.; Perez, A.; Piazza, A.; Ruggirello, G.; Taboada, H.

    2000-01-01

    The Atomic Energy Commission of Argentina has been involved in the Reduced Enrichment for Research and Test Reactors Program since 1978. The most relevant milestones of the program, regarding fuel R and D activities, were the development and manufacturing at industrial scale of U 3 O 8 dispersed fuel assemblies and the conversion of the RA-3 reactor core to LEU fuel. More recently, the activities were focused in the development of high density U 3 Si 2 fuel with a density of 4.8 gU/cm 3 and the improvement of the manufacturing process of U 3 Si 2 powder. Currently one of the main objectives is to develop and qualify the technology for the production of high-density LEU fuel elements using U-Mo alloy. Several alternative ways to obtain U-Mo powder are under development with the aim of evaluating plant scale production and costs. To boost this program the main research reactor of Argentina, the RA-3, will be upgraded to 10 MW early in 2001 and the hot cells at the Ezeiza Atomic Center are fully operational after important investments. Significant progresses were also carried out in the development of LEU targets for the production of Mo 99 . Experimental work has demonstrated the feasibility of the manufacturing and radiochemical processing of miniplate targets prepared with dispersed UAl x , maintaining the geometry and the alkaline processing of the HEU targets used so far. (author)

  7. Population structure in Argentina.

    Directory of Open Access Journals (Sweden)

    Marina Muzzio

    Full Text Available We analyzed 391 samples from 12 Argentinian populations from the Center-West, East and North-West regions with the Illumina Human Exome Beadchip v1.0 (HumanExome-12v1-A. We did Principal Components analysis to infer patterns of populational divergence and migrations. We identified proportions and patterns of European, African and Native American ancestry and found a correlation between distance to Buenos Aires and proportion of Native American ancestry, where the highest proportion corresponds to the Northernmost populations, which is also the furthest from the Argentinian capital. Most of the European sources are from a South European origin, matching historical records, and we see two different Native American components, one that spreads all over Argentina and another specifically Andean. The highest percentages of African ancestry were in the Center West of Argentina, where the old trade routes took the slaves from Buenos Aires to Chile and Peru. Subcontinentaly, sources of this African component are represented by both West Africa and groups influenced by the Bantu expansion, the second slightly higher than the first, unlike North America and the Caribbean, where the main source is West Africa. This is reasonable, considering that a large proportion of the ships arriving at the Southern Hemisphere came from Mozambique, Loango and Angola.

  8. Geochronology of the Rio Formoso estuarine by {sup 210}Pb

    Energy Technology Data Exchange (ETDEWEB)

    Arruda, Gilberto N.; Lyra, Denilson T.; Melo, Julyanne T.B.; Farias, Emerson E.G.; Franca, Elvis J.; Santos, Thiago O., E-mail: gnarruda@cnen.gov.br, E-mail: denilsonengseg@gmail.com, E-mail: julyanne.melo@ufpe.br, E-mail: emersonemiliano@yahoo.com.br, E-mail: ejfranca@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Souza Neto, Joao A., E-mail: adauto@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

    2015-07-01

    Uranium series disequilibrium is useful for dating methods, in which profile sediments can be considered as historical records of anthropogenic events regarding the distribution and impacts of chemical substances on the environment. In this study, 2 deep sediment profiles (about 1 m) were collected, layered at each 3 cm, oven-dried and homogenized. The radiochemical separation of {sup 210}Pb consisted of using hydrobromic acid and an ion exchange resin (DOWEX) for precipitating {sup 210}Pb in the form of lead chromate. After 10 days, the radioactivity was therefore measured by means of the low level gas flow proportional counter, model S5-XLB, from Canberra. Sedimentation rate were obtained by CIC (Constant Initial Concentration) model assumes a constant sedimentation rate throughout the period over which unsupported {sup 210}Pb is measurable. Some sediment profiles were not dated since the percentage of sand was quite high in top layers or a high percentage of organic matter and water in excess were observed in the all sediment samples. {sup 210}Pb geochronology was successfully applied to age nine sediment profiles, in which higher sedimentation rates were observed in the middle portion of the estuarine probably related to shrimp farming impacts. By using geochronology, the detection of human impacts on chemical element distribution could be enhanced in the case of environmental monitoring studies in the Rio Formoso estuarine. (author)

  9. Geochronology of the Rio Formoso estuarine by 210Pb

    International Nuclear Information System (INIS)

    Arruda, Gilberto N.; Lyra, Denilson T.; Melo, Julyanne T.B.; Farias, Emerson E.G.; Franca, Elvis J.; Santos, Thiago O.; Souza Neto, Joao A.

    2015-01-01

    Uranium series disequilibrium is useful for dating methods, in which profile sediments can be considered as historical records of anthropogenic events regarding the distribution and impacts of chemical substances on the environment. In this study, 2 deep sediment profiles (about 1 m) were collected, layered at each 3 cm, oven-dried and homogenized. The radiochemical separation of 210 Pb consisted of using hydrobromic acid and an ion exchange resin (DOWEX) for precipitating 210 Pb in the form of lead chromate. After 10 days, the radioactivity was therefore measured by means of the low level gas flow proportional counter, model S5-XLB, from Canberra. Sedimentation rate were obtained by CIC (Constant Initial Concentration) model assumes a constant sedimentation rate throughout the period over which unsupported 210 Pb is measurable. Some sediment profiles were not dated since the percentage of sand was quite high in top layers or a high percentage of organic matter and water in excess were observed in the all sediment samples. 210 Pb geochronology was successfully applied to age nine sediment profiles, in which higher sedimentation rates were observed in the middle portion of the estuarine probably related to shrimp farming impacts. By using geochronology, the detection of human impacts on chemical element distribution could be enhanced in the case of environmental monitoring studies in the Rio Formoso estuarine. (author)

  10. The Paleozoic-Mesozoic recycling of the Rakaia Terrane, South Island, New Zealand : sandstone clast and sandstone petrology, geochemistry, and geochronology

    International Nuclear Information System (INIS)

    Wandres, A.M.; Bradshaw, J.D.; Ireland, T.

    2005-01-01

    The Torlesse terranes - part of the New Zealand Eastern Province - are accretionary complexes that comprise an enormous volume of quartzofeldspathic sandstones and mudstones with subsidiary conglomerates plus minor oceanic assemblages. Two terranes are recognised in the South Island - the Permian to Late Triassic Rakaia Terrane and the Late Jurassic to Early Cretaceous Pahau Terrane. Sandstone clasts from two Rakaia Terrane and two Pahau Terrane conglomerates were collected. We present the first combined detailed information on petrography and geochemistry of Torlesse conglomerate sandstone clasts and use our own and published U-Pb SHRIMP detrital zircon age data to demonstrate the recycling of the Rakaia Terrane into Rakaia strata itself and into Pahau Terrane strata. Sandstone clast major and trace element chemical data largely support petrographic observations derived from thin-section analysis. The similarities of petrographic and geochemical data between sandstone clasts from the Rakaia Terrane and Rakaia sandstones suggest that clasts in the Permian Te Moana and Late Triassic Lake Hill Conglomerates were derived by autocannibalistic reworking of older, consolidated, Rakaia sediments. Data from sandstone clasts from the Pahau Terrane suggest that uplift of the Rakaia Terrane continued into the Cretaceous. These Pahau Terrane clasts indicate that at the time of the Pahau sedimentation Permian to early Late Triassic Rakaia rocks were exposed and recycled into the Pahau Basin. (author). 57 refs., 8 figs., 3 tables

  11. Tectonic-and petrological interpretation of geochronological data on the basement at the Southeast border of the Quadrilatero Ferrifero, Minas Gerais, Brazil

    International Nuclear Information System (INIS)

    Cordani, U.G.; Kawashita, K.; Mueller, G.; Quade, H.; Reimer, V.; Roeser, H.

    1980-01-01

    In an attempt to elucidate the regional geological evolution of the Ouro Preto and Mariana Districts, SE Quadrilatero Ferrifero, Minas Gerais, the available petrographical and structural data were interpreted together with 5 Rb/Sr and 7 K/Ar age determinations. Various types of metamorphic rocks were identified, and four phases of regional petrographic evolution could be distinguished: a) pre-metamorphic phase indicated by relict sedimentary and other textures; b) pre-deformation metamorphic phase, manifested by several minerals, such as microcline; c) major syntectonic crystallization phase associated with the main regional diastrophism, presumaby the Minas orogeny; d) post-deformation phase, with retrograde metamorphic minerals. With one exception, the apparent K/Ar ages obtained on biotites and amphiboles were concordant, ranging between 480 and 540 m.y., and can be referred to the terminal episodes of cooling in the Brazilian cycle. The Rb/Sr data obtained from 3 whole-rock analyses, when plotted on a Sr 87 /Sr 86 - Rb 87 /Sr 86 diagram, indicated an age of approximately 2.000m.y., with an initial Sr 87 /Sr 86 ratio of 0.711. In this diagram, 2 other speciments from a single outerop plotted significantly above of the reference isochron of 2.000m.y. The apparent ages of about 2.700 m.y. are concordant with those for the Barbacena Group which occurs more toward the eastern side of the study area. From interpretation of petrographical and structural data, the following regional geological evolution can be inferred; a)2.700m.y. - Formation of rocks during the pre-Minas episode (diastrophism in Barbacena Series, or in the Bacao Complex; b) 2.000m.y. - Trans-Amazonian cycle - Main phase of syntectonic crystallization - Minas Series diastrophism; c) 500-600m.y. - Brazilian cycle - retrograde metamorphism, thrust tectonics and regional fracturing. (Author) [pt

  12. 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

  13. Palaeozoic polymetamorphism in the North Qinling orogenic belt, Central China: Insights from petrology and in situ titanite and zircon U-Pb geochronology

    NARCIS (Netherlands)

    Li, Y.; Zhou, H.; Li, Q.L.; Xiang, H.; Zhong, Z.Q.; Brouwer, F.M.

    2014-01-01

    The Qinling orogenic belt experienced multiple phases of orogenesis during the Palaeozoic. Unraveling the timing and P- T conditions of these events is the key to understanding the convergence processes between the South China and the North China Blocks. The Songshugou Complex, located in the

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

    Science.gov (United States)

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

    1996-01-01

    The Late Neoproterozoic (735-702 Ma) Robertson River Igneous Suite includes at least eight plutons ranging in composition from syenogranite to alkali feldspar granite to alkali feldspar syenite. These plutons intruded Mesoproterozoic (1.2-1.0 Ga) gneissic basement of the Blue Ridge anticlinorium in northern and central Virginia during an early episode of Laurentian rifting. Robertson River plutons range in composition from metaluminous to peralkaline and, relative to other granite types, exhibit compositional characteristics of A-type granitoids including (1) marked enrichment in Nb, Zr, Y, REE (except Eu), and Ga, (2) high Ga/Al and FeO(total)/MgO, and (3) depletion of Ba and Sr. High Ga/Al ratios are particularly diagnostic of the suite and serve as an effective discriminant between originally metaluminous and peralkaline bulk compositions, providing a useful proxy for widely used indicators based on major elements that are prone to remobilization. U-Pb isotopic analyses of zircons indicate that the suite was emplaced in two pulses, occurring at 735 to 722 and 706 to 702 Ma. Metaluminous magmas were emplaced during both pulses, formed most of the main batholith, and fractionated as independent, time-correlative groups. Peralkaline magmas were emplaced only during the final pulse, formed a volcanic center that erupted unknown quantities of rhyolite, and experienced a style of fractionation similar to the metaluminous types. Differences in Ce/Nb, Y/Nb, and Yb/Ta ratios suggest that the metaluminous and peralkaline magmas were derived from different sources. The Robertson River Igneous Suite is part of a regional group of Late Neoproterozoic (760-700 Ma) plutons including at least 20 other A-type granitoid bodies exposed throughout the Laurentian terrane of Virginia and northwestern North Carolina. Like the Robertson River, most of the other granitoids are metaluminous in composition, typically form multi-intrusive, elongate plutons, and are not geographically constrained to the vicinity of major Neoproterozoic volcanic centers. The Late Neoproterozoic plutons of the Laurentian Appalachians are similar in lithology, composition, and style of emplacement to Miocene granitoids that occur on the southern flanks of the present Red Sea rift and that are considered a younger analog of the Appalachian plutons. However, the Red Sea granitoids were emplaced within a few million years of the initial development of oceanic crust whereas the Appalachian plutons appear largely to have pre-dated development of the Iapetus Ocean by about 130 my.

  15. Research reactors in Argentina

    International Nuclear Information System (INIS)

    Carlos Ruben Calabrese

    1999-01-01

    Argentine Nuclear Development started in early fifties. In 1957, it was decided to built the first a research reactor. RA-1 reactor (120 kw, today licensed to work at 40 kW) started operation in January 1958. Originally RA-1 was an Argonaut (American design) reactor. In early sixties, the RA-1 core was changed. Fuel rods (20% enrichment) was introduced instead the old Argonaut core design. For that reason, a critical facility named RA-0 was built. After that, the RA-3 project started, to build a multipurpose 5 MW nuclear reactor MTR pool type, to produce radioisotopes and research. For that reason and to define the characteristics of the RA-3 core, another critical facility was built, RA-2. Initially RA-3 was a 90 % enriched fuel reactor, and started operation in 1967. When Atucha I NPP project started, a German design Power Reactor, a small homogeneous reactor was donated by the German Government to Argentina (1969). This was RA-4 reactor (20% enrichment, 1W). In 1982, RA-6 pool reactor achieved criticality. This is a 500 kW reactor with 90% enriched MTR fuel elements. In 1990, RA-3 started to operate fueled by 20% enriched fuel. In 1997, the RA-8 (multipurpose critical facility located at Pilcaniyeu) started to operate. RA-3 reactor is the most important CNEA reactor for Argentine Research Reactors development. It is the first in a succession of Argentine MTR reactors built by CNEA (and INVAP SE ) in Argentina and other countries: RA-6 (500 kW, Bariloche-Argentina), RP-10 (10MW, Peru), NUR (500 kW, Algeria), MPR (22 MW, Egypt). The experience of Argentinian industry permits to compete with foreign developed countries as supplier of research reactors. Today, CNEA has six research reactors whose activities have a range from education and promotion of nuclear activity, to radioisotope production. For more than forty years, Argentine Research Reactors are working. The experience of Argentine is important, and argentine firms are able to compete in the design and

  16. History of radiobiology in Argentina

    International Nuclear Information System (INIS)

    Mayo, Jose

    2004-01-01

    Radiobiology is a multidisciplinary science dealing with ionising radiation effects on biological material. The history of Radiobiology begins in Germany and France around 1886. Radiobiology was introduced in Argentina in 1926 at the Institute of Oncology Angel H. Roffo as a biomedical research branch. Later on in 1957 was incorporated at the National Atomic Energy Commission (CNEA) of Argentina as a result of the newly started nuclear activities in Argentina. Prior that time no Radiobiology research existed in Argentina. To fill this need a Project to create new laboratories was elaborated by the CNEA. New laboratories in Radiobiodosimetry, Cellular Radiobiology, Radiopathology, Radiomicrobiology, Genetics and Somatic Effects were created. Human resources on different areas of Radiobiology were formed with the assistance of IAEA. With professional and technical personnel specialized in Radiobiology at the beginning of the 1970 decade, the transference of fundamental and applied research to others laboratories started. (author)

  17. 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

  18. The health crisis in Argentina.

    Science.gov (United States)

    Escudero, José Carlos

    2003-01-01

    The health crisis in Argentina is part of the larger crisis that has resulted from a collapse in the country's economic and political systems. After a brief review of the country's history over the last century, from international success story to economic failure, the author explains the health crisis in particular and the social crisis in general in terms of failed neoliberal policies imposed on Argentina by the United States and International Monetary Fund through the mediation of the country's political class.

  19. Operating practical experience at Argentina

    International Nuclear Information System (INIS)

    Quihillalt, Oscar

    1997-01-01

    Operating experiences of Atucha-1 and Embalse Nuclear Power Plants were discussed in this work. The technical and economic aspects, such as reliability, availability, personnel training, operating costs, prices and market, which exercise influence upon Argentina nuclear energy policy, mainly on the power electric generation by nuclear power plants were considered. Finally the current status of the nucleoelectric sector in Argentina and forecasting were analysed

  20. Characterization of agua de Ramon marbles, Cordoba Province, Argentina

    International Nuclear Information System (INIS)

    Tourn, S.; Castro, L. . E mail: selvia@fcen.uba.ar, lilianacastro@fibertel.com.ar

    2004-01-01

    Agua de Ramon district is located in the NW of Cordoba, Argentina, between 3 49' and 30 0 52' S and 65 0 21' and 65 0 24' W, in the Eastern Pampean Range setting. It was a very important tungsten district until the end of 1950'decade when tungsten mining became of no economic interest. The objective is to report for the first time the petrological, mineralogical and geochemical characteristics of several marble lenses located in the sourthern of the area. Marble outcrops are lenticular ranging from 1 m to 80 m in length and 0.50 m to 20 m width. They appear massive, fine-grained and in light colors (white, pale green, very light brown and pale gray). These last varieties show a distinct banded structure due to little differences in color. These marbles are mainly composed of magnesian calcite accompanied by minor amounts of dolomite, forsterite, humite group minerals, tremolite, talc, serpentine and clinochlore, and scheelite, sphene, apatite and opaque minerals like hematite, magnetite, illmenite, pirrothite and pyrite as accessory minerals. Major chemical analyses indicate a relatively high SiO2 and MgO content, and minor CaO, in comparison with marbles of this type. Mineral paragenesis was useful to evaluate metamorphism conditions in this area [es

  1. Piedra lata terrane of Uruguay: Rb-Sr geochronological data of two new paleoproterozoic (transamazonian) granitoids

    International Nuclear Information System (INIS)

    Cingolani, C; Bossi, J; Varela, R; Maldonado, S.; Pineyro, D.; Schipilov, A

    2001-01-01

    The Precambrian basement of Uruguay consists of three major terranes separated and crosscut by wide NE-striking subvertical transcurrent shear zones. The western terrane as a part of the Rio de la Plata Craton is known as the Piedra Alta Terrane (PAT). This is separated from the Nico Perez Terrane by the Sarandi del Yi-Piri olis subvertical shear zone (Bossi et al., 1993). A mafic dykes complex intruded the PAT at 1.8 Ga and was not later deformed. The PAT has equivalent rocks in the igneous-metamorphic basement of Tandilia region and the Martin Garcia Island, Buenos Aires Province, Argentina (Dalla Salda et al., 1988; Cingolani and Dalla Salda, 2000). The PAT shows no evidence of the Neoproterozoic orogenies and is considered a best preserved Paleoproterozoic block (Transamazonian Cycle). It contains three E-W trending belts of volcano-sedimentary rocks with low grade metamorphism. These are from south to north: Pando, San Jose and Andresito belts (Bossi et al., 1996). Associated with them, three granitic-gneissic zones he Ecilda Paullier, Florida and Feliciano- were recognized with magmatic intrusives emplaced at different crustal levels. The San Jose belt is the largest supracrustal unit and contains abundant volcanic and volcaniclastic rocks of low grade metamorphic (Paso Severino Fm.) with sheets of granitic rocks intercalated (Mutti et al., 1996; Bossi et al., 1996). The associated granitic rocks are of large areal extension, mostly granodiorites and tonalites, and minor monzogranite and gabbro (e.g. Cerro Rospide region), including xenoliths from Paso Severino Fm. Towards the north of the San Jose belt an important Florida granitized zone is developed in the central part of the PAT, where the Pintos massif was recognized. The main purpose of this contribution is to offer new Rb-Sr geochronological data from two granitoid units, The Cerro Rospide intrusive in Paso Severino Fm. and Pintos massif included in medium grade migmatic-metamorphic complex and its

  2. Preliminary results of U/Pb geochronology in Meridional Espinhaco Mountain

    International Nuclear Information System (INIS)

    Machado, N.; Schrank, A.; Abreu, F.R. de; Knauer, L.G.; Abreu, P.A.A.

    1989-01-01

    Some samples of the constituent unities from Meridional Espinhaco Mountain for geochronology determining by U/Pb method are presented. The analytical techniques described by Krogh and the Davis linear regression program are used for treating these samples. (author)

  3. Geochronology and geochemistry by nuclear tracks method: some utilization examples in geologic applied

    International Nuclear Information System (INIS)

    Poupeau, G.; Soliani Junior, E.

    1988-01-01

    This article discuss some applications of the 'nuclear tracks method' in geochronology, geochemistry and geophysic. In geochronology, after rapid presentation of the dating principles by 'Fission Track' and the kinds of geological events mensurable by this method, is showed some application in metallogeny and in petroleum geolocy. In geochemistry the 'fission tracks' method utilizations are related with mining prospecting and uranium prospecting. In geophysics an important application is the earthquake prevision, through the Ra 222 emanations continous control. (author) [pt

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

    Science.gov (United States)

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

    2017-04-01

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

  5. Norm survey in Argentina

    International Nuclear Information System (INIS)

    Canoba, Analia Cecilia; Gnoni, Gabriela Alejandra; Truppa, W.

    2008-01-01

    The oil and gas industry, which is especially significant in Argentina, is one industry that concentrates natural radionuclides during its processes. In addition, there are a few underground mines under development, where radon levels may be high. The Nuclear Regulatory Authority of Argentina (ARN) carried out a project with the objective of evaluating NORM, mainly in these types of industries. Eight facilities were characterized, three related to the gas industry, four related to the oil industry and a survey of radon gas in a gold underground mine. First, background measurements were made and then a screening survey was carried out to detect values above background. Of the values obtained, 57% were in the background range, 19% were below 2 μSv/h, 15% were in the range 2-10 μSv/h and 9% were above 10 μSv/h. Some values were as high as 400 μSv/h. The annual effective doses were estimated to be in the range 0.02-1.6 mSv/a. Samples were taken and later analysed by gamma spectrometry, liquid scintillation and fluorimetry. It was confirmed that the main radionuclides involved in the oil and gas extraction process are 226 Ra and 228 Ra. The radium isotope concentrations measured in some samples were above the exemption values established by the International Basic Safety Standards. Elevated radon levels were detected in gas facilities and in the gold mine under development. The values obtained in gas facilities showed that radon concentrates in the ethane and propane flows. As the flows in the gas industry are confined, it does not mean an exposure during normal operation. In the case of the gold mine, the values detected were informed to the pertinent authorities as well as the facility in order to take actions to reduce concentrations below the action levels. Finally, protective measures to reduce occupational doses in the cleaning and maintenance processes were suggested, as well as for storage of NORM-contaminated items. (author)

  6. Coccocypselum pulchellum (Rubiaceae, nuevo registro para Argentina

    Directory of Open Access Journals (Sweden)

    Elsa L. Cabral

    2007-01-01

    Full Text Available Se cita Coccocypselum pulchellum por primera vez para Argentina, en Predio Guaraní, Misiones. Esta es la tercera especie de Coccocypselum registrada para la flora de Argentina junto con C. hasslerianum y C. lanceolatum. Se incluyen descripciones, ilustraciones y una clave para reconocer las tres especies argentinas de Coccocypselum.

  7. Argentina: Background and U.S. Relations

    Science.gov (United States)

    2008-11-05

    Comercio Internacional, Y Culto, Comunicado de la Cancillería Argentina, September 11, 2008. 43 A. Rebossio, "Fernández Acusa al FBI de Desestablizar...Argentina," El País (Madrid), September 13, 2008. 44 “Argentina Slams Witness in Cash Suitcase Scandal,” Associated Press Newswires, November 4, 2008

  8. Climatology of hail in Argentina

    Science.gov (United States)

    Mezher, Romina N.; Doyle, Moira; Barros, Vicente

    2012-10-01

    The annual cycle, annual and seasonal frequency and geographical distribution of hail in Argentina during the 1960-2008 period are examined. Eight regions covering the whole territory were defined based on the correlation of the mean annual hail frequency between all weather stations. Regions lying between 30° and 40°S as well as those dominated by mountains present the highest hail frequencies in Argentina. The eastern and coastal areas of the country experience hail events mainly during springtime but they may start in late winter and continue through the beginning of summer. Events in western and central Argentina also predominate in spring but the maximum frequencies are observed during summer months. Trends in the annual number of hail events calculated for each region indicate that events in northwestern and northeastern Argentina have been increasing as well as in southern Patagonia. On the other hand, in central Argentina, southern Buenos Aires-La Pampa, northern Buenos Aires-Litoral and northern Patagonia trends are negative and statistically significant in the first two regions, basically by the decrease of events during spring and summer.

  9. Nuclear Activities in Argentina, 2010

    International Nuclear Information System (INIS)

    Ferreri, J.C.; Ferreri, J.C.; Clausse, A.; Clausse, A.; Clausse, A.; Ordonez, J.P.; Mazzantini, O.A.

    2011-01-01

    Nuclear activities in Argentina are restarted. After almost two decades of near stagnation, the governments political decision of August 2006 regarding electrical energy production, considered the nuclear option as a valid one to solve the problems of the growing demand of electrical energy. This decision triggered again the activities related to the finalization of the third nuclear power reactor (Atucha-II), now actively progressing, the construction of a prototype of the CAREM integral advanced reactor, the life extension of the Embalse CANDU nuclear power plant (NPP) and the studies for the emplacement of a fourth NPP in an appropriate site. In all those years of near stagnation, there were notable exceptions related to the design and construction of experimental and radioisotope production reactors, led by INVAP, a state-owned industry, which exported its production. The accompanying industries of nuclear fuel elements production also remained active, given the demand of the two active NPPs. Meanwhile, the National Atomic Energy Commission of Argentina continued the efforts on research and development that were at the base of the technological achievements of the nuclear activities in Argentina. Nuclear safety studies associated with Atucha II and Embalse NPPs and radiological safety were also a substantive part of the continued efforts by Nucleo-Electrica de Argentina SA and the Nuclear Regulatory Authority of Argentina

  10. Country watch. Argentina.

    Science.gov (United States)

    Perez, P

    1994-01-01

    The Argentine Network of Women Living with HIV/AIDS (ANW) provides general information about acquired immunodeficiency syndrome (AIDS), assistance in assessing medications through state and private services, and information concerning and referrals to nongovernmental organizations (NGOs) and governmental social services to low income women who have been diagnosed with human immunodeficiency virus (HIV) infection. Workshops allow the women to become more active on their own behalf and contribute to the reorientation of health and social services to better meet their needs. Due to the stigma attached to AIDS in Argentina, ANW works to ensure the human rights of these women through participation in the Ministry of Interior Programme against Discrimination and in public events that inform the community about the concerns of HIV positive women with regard to discrimination. A bulletin provides scientific and medical information, news on activities, model advocacy and policy statements, and addresses of support agencies. Contributions are accepted from all HIV positive women. In order to reach isolated cases outside of the capital, links are maintained with other AIDS organizations in the nation.

  11. Argentina and Brazil

    International Nuclear Information System (INIS)

    Gamba-Stonehouse, V.

    1991-01-01

    This paper reports that security is defined in different ways by many international actors. To some, security is tied to the definition of an external threat to borders, as in the case of the NATO countries. To other, security is related to development, as in the case of most Third World countries. but notwithstanding different definitions, all countries recognize that the essence of security is the survival of the nation-state itself. The nuclear programs of Argentina and Brazil are among the oldest, most sophisticated and advanced nuclear programs anywhere in the Third World. The programs have never been explained on the basis of threat perception, and in this regard perhaps they constitute the most atypical form of nuclear proliferation known to date. Not surprisingly, any attempt to explain the rationale for the Brazilian and Argentine nuclear programs based on common issues of threat =merely confuses the issue. Thus, nationalism, the search for national identity and pride, the need to express self-sufficiency and the desire to keep options open in an insecure and evolving world order must all be analyzed to comprehend the likelihood of future types of nuclear proliferation. Meanwhile, the study of the contemporary era of Argentine-Brazilian nuclear rapprochement may provide new insights into the complex reasoning behind the decision of countries to go nuclear

  12. Pampa Húmeda, Argentina

    Directory of Open Access Journals (Sweden)

    Néstor C. Di Leo

    2007-01-01

    Full Text Available La radiación fotosintéticamente activa (PAR es importante como variable de entrada de energía en diversos procesos biológicos y su evaluación temporal tiene particular interés en el monitoreo de cultivos. Los datos de reflectancia espectral, obtenidos mediante sensores remotos, son adecuados para proporcionar observaciones de fenómenos que se relacionan con aspectos ecofisiológicos de las cubiertas vegetales, incluyendo a la productividad primaria neta (NPP. Ésta constituye una de las pocas fuentes de información acerca de los procesos del ciclo del carbono en escalas regionales o globales. La NPP se relaciona con la eficiencia del uso de la luz a través de la radiación fotosintéticamente activa absorbida (APAR y representa un indicador agroecológico de utilidad para valorar la utilización productiva del territorio. El objetivo de este trabajo es presentar un aporte metodológico a la agroecología, mediante las caracterizaciones de la NPP y la APAR, en tres situaciones geográficas y productivas de la Pampa Húmeda, Argentina.

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. Crisis de la prensa Argentina

    Directory of Open Access Journals (Sweden)

    Federico Rey Lennon

    2015-01-01

    Full Text Available La magnitud de la crisis económica Argentina es enorme y difícil saber hasta cuando se extenderá, agravada por una situación política frágil. La actual recesión ha hecho caer la inversión publicitaria a los niveles más bajos de los últimos años. De 1997 al 2001 la circulación de la prensa Argentina cayó en el 36 por ciento. El riesgo en Argentina es la eventual extranjerización de casi todos los medios de comunicación.

  18. Mississippian lamprophyre dikes in western Sierras Pampeanas, Argentina: Evidence of transtensional tectonics along the SW margin of Gondwana

    Science.gov (United States)

    Martina, Federico; Canelo, Horacio N.; Dávila, Federico M.; de Hollanda, María Helena M.; Teixeira, Wilson

    2018-04-01

    In the Famatina range, Sierras Pampeanas of Argentina (SW Gondwana), subvertical calc-alkaline lamprophyric dike swarms crop out through >300 km. The dikes cut Ordovician units with a prominent NW-SE trending and are covered by continental sedimentary successions of Pennsylvanian to Permian age. The dikes show a strong structural control associated with Riedel fault systems. Detailed field analysis suggested a ∼N-S opening direction oblique to the attitude of dike walls and a left-lateral transtensional tectonics during the emplacement. 40Ar/39Ar geochronology of a lamprophyric sample defined a crystallization age (plateau; whole rock) of 357.1 ± 7.1 Ma (MSWD = 2.3). Coetaneous ductile zones with dominant strike-slip motion, documented along western Argentina for >600 km, suggest a regional event in SW Gondwana during the Mississippian. We propose that this deformation was the result of the counterclockwise fast rotation of Gondwana between 365 and 345 Ma, when the Famatina range and western Argentina occupied a sub-polar position. A transform margin along SW Gondwana better explains our (and others) data rather than a subduction margin. This scenario is also consistent with the occurrence of A-type granites and normal-fault basins within the foreland as well as bimodal volcanics.

  19. 40Ar/39Ar geochronology of terrestrial pyroxene

    Science.gov (United States)

    Ware, Bryant; Jourdan, Fred

    2018-06-01

    Geochronological techniques such as U/Pb in zircon and baddeleyite and 40Ar/39Ar on a vast range of minerals, including sanidine, plagioclase, and biotite, provide means to date an array of different geologic processes. Many of these minerals, however, are not always present in a given rock, or can be altered by secondary processes (e.g. plagioclase in mafic rocks) limiting our ability to derive an isotopic age. Pyroxene is a primary rock forming mineral for both mafic and ultramafic rocks and is resistant to alteration process but attempts to date this phase with 40Ar/39Ar has been met with little success so far. In this study, we analyzed pyroxene crystals from two different Large Igneous Provinces using a multi-collector noble gas mass spectrometer (ARGUS VI) since those machines have been shown to significantly improve analytical precision compared to the previous single-collector instruments. We obtain geologically meaningful and relatively precise 40Ar/39Ar plateau ages ranging from 184.6 ± 3.9 to 182.4 ± 0.8 Ma (2σ uncertainties of ±1.8-0.4%) and 506.3 ± 3.4 Ma for Tasmanian and Kalkarindji dolerites, respectively. Those data are indistinguishable from new and/or published U-Pb and 40Ar/39Ar plagioclase ages showing that 40Ar/39Ar dating of pyroxene is a suitable geochronological tool. Scrutinizing the analytical results of the pyroxene analyses as well as comparing them to the analytical result from plagioclase of the same samples indicate pure pyroxene was dated. Numerical models of argon diffusion in plagioclase and pyroxene support these observations. However, we found that the viability of 40Ar/39Ar dating approach of pyroxene can be affected by irradiation-induced recoil redistribution between thin pyroxene exsolution lamellae and the main pyroxene crystal, hence requiring careful petrographic observations before analysis. Finally, diffusion modeling show that 40Ar/39Ar of pyroxene can be used as a powerful tool to date the formation age of mafic

  20. 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

  1. 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

  2. NREL technical assistance to Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Lilienthal, P. [National Renewable Energy Lab., Golden, CO (United States)

    1997-12-01

    This paper describes assistance to Argentina from the National Renewable Energy Laboratory which has touched on four programs: tariff analysis for rural concessions programs; wind/diesel hybrid retrofits in Patagonia; small hybrid systems designs for rural schools; an assessment of wind resources. The paper expands briefly on the first two points.

  3. Geochronological determination of the pegmatites from Rio de Janeiro State

    International Nuclear Information System (INIS)

    Oliveira Menezes, S. de; Cordani, U.G.; Teixeira, W.

    1987-01-01

    Samples of muscovite and plagioclase were collected from the pegmatites located in the counties of Niteroi and Sao Goncalo, State of Rio de Janeiro. Geochronological Research Center of the University of Sao Paulo has selected some samples for pottasium-argon and rubidium-strontium analysis. Three samples of muscovite analysed by K-Ar dating method lave ages between 437+-13 and 447+-16 m.y and two others, by Rb-Sr dating method, gave 495+-15 and 500+-13 m.y.. One sample of plagioclase analysed by K-Ar method gave age of 337+-16 m.y.. In this paper, the locations of the analysed samples are described and the samples of vicinity are listed in the Appendix. Interpretation of the radiometrio ages and discussion of results are made. Taking into account the results of Table l and the geologic setting of the pegmatities sample in Niteroi and Sao Goncalo, we way conclude that all cooling ages (440-550 m.y.) are related to the Brasiliano Orogeny. These pegmatites are regard as having same geological history and their ages are supposed 500 m.y.. (author) [pt

  4. Geochronological determination of pegmatites from Rio de Janeiro state

    International Nuclear Information System (INIS)

    Oliveira Menezes, S. de; Cordani, U.G.; Teixeira, W.

    1987-01-01

    Samples of muscovite and plagioclase were collected from the pegmatites located in the counties of Niteroi and Sao Goncalo, State of Rio de Janeiro. Geochronological Research Center of the University of Sao Paulo has selected some samples for potassium-argon and rubidium-strontion analysis. Three samples of muscovite analysed by K-Ar dating method gave ages between 437±13 and 447±16 m.y and two others, by Rb-Sr dating method, gave 495±15 and 500±13 m.y.. One sample of plagioclase analysed by K-Ar method gave age of 337±16 m.y.. In this paper, the locations of the analysed samples are described and the samples of vicinity are listed in the Appendix. interpretation of the radiometric ages and discussion of results are made. Taking into account the results of Table 1 and the geologic setting of the pegmatites sampled in Niteroi and Sao Goncalo, we way conclude that all cooling ages (440-550 m.y.) are related to the Brasiliano Orogeny. These pegmatites are regard as having same geological history and their ages are supposed 500 m.y [pt

  5. Geochronology and geochemistry of upper proterozoic granites from Southern Benin

    International Nuclear Information System (INIS)

    Cordani, U.G.; Kawashita, K.; Vancini, K.R.B.; Cadoppi, P.; Sacchi, R.

    1993-01-01

    The Upper Proterozoic basement of Benin, like that of nearby Nigeria and like the polycyclic basement of Central Hoggar, belongs to the hinterland of the Pharusian Chain (Pan-African Trans-Saharan Belt) generated by the collision between the (passive) margin of the West African craton and the (reactivated) margin of the Tuareg Shield and its southern extension. Rb-Sr dating of sub alkaline, meta-aluminums, syn-Kinematic granite forming tabular bodies near Dassa-Zoume and near Save yielded two WR isochron ages of 650 ± 35 Ma (I.R. = 0.7043) and 705 ± 70 Ma (I.R. = 0.7045). Emplacement of these bodies was clearly controlled by trans current movements along the Kandi Fault System. The analyzed granites are comparable with those of Central Hoggar and North-Central Nigeria on the ground of field, geochronological and geochemical data; they also display some affinities with the late-tectonic granites of the Adrar des Iforas. They are expected to find their Brazilian continuation in the Chaval Granitoids west of Fortaleza, but data for comparison are inadequate. (author)

  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. The geotectonic evolution of southern part of Sao Francisco Craton, based in geochronologic interpretation

    International Nuclear Information System (INIS)

    Teixeira, W.

    1985-01-01

    Interpretation of available radiometric data from poly metamorphic terranes of southern part of the Sao Francisco Craton demonstrates the importance of geochronology as a tool in the study of ancient crustal evolution. In addition, radiometric study of basic intrusive magmatism helps define the most important epochs of crustal rifting during the Proterozoic. The definition of the southern border of the cratonic area based on distinctive age patterns of the geochronological provinces is also discussed. Finally, the geochronologic evolution of the Bambui platform cover is presented. Approximately 250 radiometric age determinations (Rb-Sr, K-Ar and Pb-Pb methods) were interpreted principally through the use of iso chronic diagrams. The geologic history tectonomagnetic events identified in this study is compared to the crustal evolution of similar segments of the Sao Francisco Craton and elsewhere. (author)

  11. A geochemical and geochronological section through the Eastern Aegean

    Science.gov (United States)

    Boehm, Katharina; Kuiper, Klaudia; Vroon, Pieter; Wijbrans, Jan

    2017-04-01

    The convergence of Africa and Eurasia and the subduction of a oceanic lithosphere of narrow basins between Gondwana terranes has controlled the geological evolution of the Eastern Mediterranean region since the Cretaceous. This resulted in back-arc extension and lithospheric thinning caused by slab roll-back together with the westward extrusion of Anatolia, in the southwards retreat and stepwise development of the subduction system and also in a low velocity seismic anomaly gap between the Cyprus and Hellenic slab and other slab segments. However, the exact timing of all these events in the Eastern Mediterranean region is still a matter of debate, and the purpose of this study is therefore to disentangle when terrains collided and slab detached in the last 30Ma. In a N-S transect magmatic rocks of the Aegean plate are studied, including volcanics from the islands Nisyros, Kos, Patmos, Chios, Lesbos and Samothraki. Major- and trace elements as well as Sr-Nd-Hf-Pb-O isotopes are used to interpret the different features of the Aegean subduction zone. With this geochemical approach the extend of upwelling hot asthenospheric material from the slab tear can be traced in the recent to Eocene volcanic rocks. The volcanic rocks give a wide scatter in classification diagrams and pose for example the question how the sodium rich volcanic products of Patmos can be explained. On the other hand Chios seems to play a key role around 15 Ma years in a phase of relatively low volcanic activity. To get a reliable timeline of the subduction in the Aegean since the Eocene we are aiming to tie our chemical and isotopic data to parallel obtained geochronological ages. New 40Ar/39Ar data will allow us to get the needed resolution for this time span and material.

  12. Nuclear Energy Stakeholders in Argentina

    International Nuclear Information System (INIS)

    Gadano, Julian

    2017-01-01

    Mr Gadano, Undersecretary for Nuclear Energy, Argentina spoke from the perspective of a country looking forward to becoming a member of the NEA. He reviewed the place of nuclear energy in his country's energy mix and called attention to its role in positively addressing the global challenges of climate change and energy security. Mr Gadano also described the federal system which governs Argentina. Drawing on his expertise as a lawmaker and nuclear regulator but also as an academic sociologist, he stressed that reaching agreement on siting initiatives for example requires a sustainable relation with stakeholders, including regional governments. This is important because in the end, 'the best project is the one you can finish'

  13. Effects of Flat Slab Subduction on Andean Thrust Kinematics and Foreland Basin Evolution in Western Argentina

    Science.gov (United States)

    Horton, B. K.; Fuentes, F.; McKenzie, N. R.; Constenius, K. N.; Alvarado, P. M.

    2014-12-01

    Debate persists over the effects of flat-slab subduction on the kinematics of overriding plate deformation and the evolution of retroarc sedimentary basins. In western Argentina, major spatial and temporal variations in the geometry of the subducting Nazca slab since ~15 Ma provide opportunities to evaluate the late Cenozoic response of the Andean fold-thrust belt and foreland basin to subhorizontal subduction. Preliminary results from several structural and sedimentary transects spanning the frontal thrust belt and foreland basin system between 31°S and 35°S reveal Oligocene-middle Miocene hinterland exhumation during normal-slab subduction followed thereafter by progressive slab shallowing with initial rapid cratonward propagation of ramp-flat thrust structures (prior to basement-involved foreland uplifts) and accompanying wholesale exhumation and recycling of the early Andean foreland basin (rather than regional dynamic subsidence). Detrital zircon U-Pb geochronologic data prove instrumental for revealing shifts in thrust-belt exhumation, defining depositional ages within the foreland basin, and constraining the timing of activity along frontal thrust structures. In both the San Juan (31-32°S) and Malargüe (34-35°S) segments of the fold-thrust belt, geochronological results for volcaniclastic sandstones and syndeformational growth strata are consistent with a major eastward advance in shortening at 12-9 Ma. This episode of rapid thrust propagation precedes the reported timing of Sierras Pampeanas basement-involved foreland uplifts and encompasses modern regions of both normal- and flat-slab subduction, suggesting that processes other than slab dip (such as inherited crustal architecture, critical wedge dynamics, and arc magmatism) are additional regulators of thrust-belt kinematics and foreland basin evolution.

  14. 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

    Mitchell, J.G., 2000. Petrogenetic evolution of late Cenozoic, post-collision volcanism in western Anatolia, Turkey. Journal of Volcanology and Geothermal Research, 102(1: 67–95. Chappell, B.W. and White, A.J.R., 2001. Two contrasting granite types, 25years later. Australian Journal of Earth Sdiences, 48(4: 489-500. Karimpour, M.H., Malekzadeh shafaroudi, A., Farmer, G.L. and Stern, C.R., 2012. Petrogenesis of Granitoids, U-Pb zircon geochronology, Sr-Nd Petrogenesis of granitoids, U-Pb zircon geochronology, Sr-Nd isotopic characteristics, and important occurrence of Tertiary mineralization within the Lut block, eastern Iran. Journal of Economic Geology, 4(1: 1-28. (in Persian with English abstract Nagudi, N., Koberl, Ch. and Kurat, G., 2003. Petrography and Geochemistry of the sigo granite, Uganda and implications for origin, Journal of African earth Sciences, 36(1: 1-14. Pearce, J.A., Harris, N.B.W. and Tindle, A.G., 1984. Trace element discrimination diagrams for thetectonic interpretation of granitic rocks. Journal of Petrology, 25(4: 956-983. Tepper, J.H., Nelson, B.K., Bergantz, G.W. and Irving, A.J., 1993. Petrology of the Chilliwack batholith, North Cascades, Washington: generation of calc-alkalinegranitoids by melting of mafic lower crust with variable water fugacity. Contributions to Mineralogy and Petrology, 113(3: 333-351.

  15. Public information activities in Argentina

    International Nuclear Information System (INIS)

    Espejo, Hector

    1998-01-01

    This is a presentation involving a description of the main guidelines and conditions under which nuclear activities have been performed in Argentina, both concerning the autonomous development for the peaceful use of nuclear energy and with regard to the way in which the community was informed of the attained levels. The particulars of each approach are shown as to delineate historical evolution as a function of the various stages of technological development. (author)

  16. The energy sector in Argentina

    International Nuclear Information System (INIS)

    2016-01-01

    This article first outlines that Argentina produces an important part of its hydrocarbon consumption and comment various aspects of this production: hydrocarbons are at the heart of the Argentinian energetic model; conventional hydrocarbon reserves are however decreasing; the public operator remains the main actor even though the market is opened to multinational companies. The article then describes the crisis faced by this energetic model: the energy balance is now a burden; the increasing unbalance between production and consumption can be explained by supply-related as well as demand-related factors; authorities must intervene on hydrocarbon prices and subsidize the oil price on the domestic market. It appears that the future for hydrocarbons in Argentina relies on non-conventional hydrocarbons. Bio-fuels, a key sector of the Argentinian economy, are a matter of trade dispute with the EU and the USA. Apart from hydroelectricity (some new projects are planned), renewable energies are very few developed in Argentina. Appendices propose a graph of the distribution of energy consumption among the different sources, a map indicating locations of the main exploited hydrocarbon deposits, a presentation of mechanisms implemented to subsidize hydrocarbon production

  17. Application of quadrupole mass spectrometer to the 40Ar-39Ar geochronological study

    International Nuclear Information System (INIS)

    Takigami, Yutaka; Nishijima, Tadashi; Koike, Toshio; Okuma, Kouichi.

    1984-01-01

    A Quadrupole Mass Spectrometer (QMS) has commonly been used for qualitative analyses of gases in organic chemistry or for monitoring the vacuum conditions in industrial machines. No attempt has been made, however, to apply it to geochronological studies because of its disadvantages such as the difficulty in obtaining precise isotope ratios due to triangular peak shapes and poor reproducibility. On the other hand, there are advantages that a QMS is relatively inexpensive and gives a shorter scanning time for analysis compared with a sector type mass spectrometer. The latter characteristics is useful for 40 Ar/ 39 Ar geochronological studies, since it gives a lower background in the QMS and the possibility to obtain many more data from one sample in a limited time. In this study, we have tried to improve a commercial QMS at many parts, such as rf-generator, quadrupole, ionization chamber, source magnet, and so on, in order to meet the requirements to use it for geochronological studies. With the use of the improved QMS equipped with an on-line microcomputer, we could obtain Ar isotope data which are sufficiently precise for the 40 Ar/ 39 Ar geochronological studies. (author)

  18. Re–Os geochemistry and geochronology of the Ransko gabbro–peridotite massif, Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Ackerman, Lukáš; Pašava, J.; Erban, V.

    2013-01-01

    Roč. 48, č. 7 (2013), s. 799-804 ISSN 0026-4598 R&D Projects: GA ČR GA13-15390S Institutional support: RVO:67985831 Keywords : Re–Os * geochronology * gabbro * Bohemian Massif * Ni–Cu mineralization Subject RIV: DD - Geochemistry Impact factor: 2.667, year: 2013

  19. Boll weevil invasion process in Argentina

    Science.gov (United States)

    The boll weevil, Anthonomus grandis grandis Boheman, is the most destructive cotton pest in the Western Hemisphere. In 1993, the pest was reported in Argentina, and in 1994 boll weevils were captured in cotton fields in the Formosa Province on the border between Argentina and Paraguay. The pest ha...

  20. Communications received from Argentina and Brazil

    International Nuclear Information System (INIS)

    1989-01-01

    The document reproduces the Joint Statement on Nuclear Policy signed by the President of Argentina and the President of Brazil on 29 November 1988 at Ezeiza, Argentina, concerning the decision of the two countries to undertake a joint fast breeder reactor project

  1. Mida õpetab Argentina finantskriis? / Karsten Staehr

    Index Scriptorium Estoniae

    Staehr, Karsten, 1962-

    2002-01-01

    Norra majandusanalüütik kirjeldab Argentina majanduspoliitikat, analüüsib tehtud vigu ning hoiatab avatud majandusega Eestit võimalike tulevaste välisshokkide eest. Diagramm: SKP kasv ja üleüldine riigieelarve tasakaal 1991-2001 Argentinas

  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. Geochronology of Quaternary glaciations from the tropical Cordillera Huayhuash, Peru

    Science.gov (United States)

    Hall, Sarah R.; Farber, Daniel L.; Ramage, Joan M.; Rodbell, Donald T.; Finkel, Robert C.; Smith, Jacqueline A.; Mark, Bryan G.; Kassel, Christopher

    2009-12-01

    The Cordillera Huayhuash in the central Peruvian Andes (10.3°S, 76.9°W) is an ideal mountain range in which to study regional climate through variations in paleoglacier extents. The range trends nearly north-south with modern glaciers confined to peaks >4800 m a.s.l. Geomorphology and geochronology in the nearby Cordillera Blanca and Junin Plain reveal that the Peruvian Andes preserve a detailed record of tropical glaciation. Here, we use ASTER imagery, aerial photographs, and GPS to map and date glacial features in both the western and eastern drainages of the Cordillera Huayhuash. We have used in situ produced cosmogenic 10Be concentrations in quartz bearing erratics on moraine crests and ice-polished bedrock surfaces to develop an exposure age chronology for Pleistocene glaciation within the range. We have also collected sediment cores from moraine-dammed lakes and bogs to provide limiting 14C ages for glacial deposits. In contrast to the ranges to the north and south, most glacial features within the Cordillera Huayhuash are Lateglacial in age, however we have identified features with ages that span ˜0.2 to ˜38 ka with moraine sets marking the onset of glacier retreat at ˜0.3 ka, ˜9-10 ka, ˜13-14 ka, ˜20-22 ka, and >26 ka. The range displays a pronounced east-west variation in maximum down-valley distance from the headwall of moraine crests with considerably longer paleoglaciers in the eastern drainages. Importantly, Lateglacial paleoglaciers reached a terminal elevation of ˜4000 m a.s.l. on both sides of the Cordillera Huayhuash; suggesting that temperature may have been a dominant factor in controlling the maximum glacier extent. We suggest that valley morphology, specifically valley slope, strongly influences down-valley distance to the maximum glacier extent and potential for moraine preservation. While regionally there is an extensive record of older (>50 ka) advances to the north (Cordillera Blanca) and to the south (Junin region), the apparent

  7. 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)

  8. 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

  9. 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.

  10. 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#

  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. Thirty-five years of geochronology in Uruguay

    International Nuclear Information System (INIS)

    Bossi, J.; Campal, N; Hartmann, L.A; Schipilov, A.; Pineyro, D

    2001-01-01

    The radiometric ages obtained abroad have been systematically integrated with the field geology over the last thirty five years. The difference between the radiometric ages and their geochronology interpretation was realized rather early in the investigations. The few opportunities for radiometric determinations of rocks and minerals required careful regional geological mapping, based on models which were predominant at the time. Untial 1965, the pre-Devonian rocks in Uruguay were divided into Archean and Algonkian. The Archean units included medium metamorphic grade rocks and all the plutonic rocks. The Algonkian units were the low metamorphic grade supracrustal belts. The tectono-stratigraphic proposal presented at the International Geological Congress in India (1960) induced the division into two orogenic cycles and the radiometric dating with the techniques available at the time: K-Ar already in use and Rb-Sr isochrons, which were considered accurate and precise. The work of Hart (1966) resulted in ten ages, grouped in two geographically separated age sets: 600-500 Ma in the southeast and ca. 2000 Ma in the south and southwest. Bossi et al. (1967) identified two orogenic cycles based on geological mapping at the 1:250,000 scale, no intermediate ages. These cycles were recognized until 1991, although some improvements occurred in limits of units and cartography and some changes in nomenclature and integration of the Rb-Sr isotopic data by Umpierre and Halpern (1971), Soliani Jr. (1986), Renne (1991, pers. comm.). The proposal of a Trans-Amazonian craton in the west (Ciclo Orogenico Antiguo) and a mobile belt in the east (Ciclo Orogenico Moderno) was accepted for 25 years. Many Brazilian (e.g., Fragoso Cesar, 1980) and some Uruguayan authors included the 'Ciclo Orogenico Moderno in the Brasiliano Cycle of Almeida (1976). The consistency of this proposal has been accepted up to today, because 800-550 Ma granitic rocks are intruded in low metamorphic grade

  13. Greenstone: uso actual en Argentina

    Directory of Open Access Journals (Sweden)

    Marcela Fushimi

    2018-04-01

    Full Text Available Este trabajo presenta las características e historia del software para crear y gestionar bibliotecas digitales Greenstone, desarrollado inicialmente por la Universidad de Waikato, Nueva Zelandia en 1997. En primer lugar, se describe la comunidad de usuarios a nivel global, focalizando en el uso actual que el software ha alcanzado en Argentina: la cantidad de implementaciones disponibles, su evolución, el tipo, tamaño y variedad de los desarrollos existentes, así como su aplicación a la gestión de repositorios digitales de ciencia y tecnología en el ámbito de las instituciones científicas, tecnológicas y de educación superior en Argentina. En segundo lugar, se detallan las acciones llevadas a cabo a partir de la creación del Centro Nacional de Promoción de Greenstone en Argentina en 2009. Datos recabados en encuestas realizadas permitieron observar que las razones predominantes para elegir esta plataforma fueron, entre otras, su facilidad de instalación y configuración, su bajo nivel de requerimiento tecnológico, la generalizada escasez de recursos humanos dedicados a esta actividad, y la complejidad que presentaban los softwares alternativos existentes en ese momento. A lo largo de estos 8 años, tanto los repositorios digitales como los sistemas que los soportan evolucionaron drásticamente, modificando el escenario actual. Paralelamente, en 2016 la nueva versión mayor de Greenstone implementó una reingeniería completa del software para su adaptación a las tecnologías en uso: XML, XSLT, Web-services y Java. Como consecuencia de esto, la comunidad de desarrollo local se plantea nuevos desafíos para la migración de las bibliotecas digitales y repositorios implementados con versiones anteriores.

  14. Bioceres: AG Biotechnology from Argentina

    Directory of Open Access Journals (Sweden)

    Roberto Feeney

    2016-04-01

    Full Text Available In this case we present a business decision-making situation in which the CEO of an Argentine Ag Biotech company, Bioceres, has to decide the best way to commercialize a new drought-tolerant transgenic technology. The company was founded by twenty three farmers, who shared a common dream that Argentina could become a benchmark in the development of Ag biotechnology. The case has strategic and financial implications, as well as decision-making situation involving a joint venture with an American biotechnology company. It also introduces to discussion the business models of Ag biotechnology companies in developing countries.

  15. Soybean biomass produced in Argentina

    DEFF Research Database (Denmark)

    Semino, Stella Maris; Paul, Helena; Tomei, Julia

    2009-01-01

    Soybean biomass for biodiesel, produced in Argentina amongst other places, is considered by some to reduce greenhouse gas emissions and mitigate climate change when compared with fossil fuel. To ensure that the production of biofuels is ‘sustainable', EU institutions and national governments...... are currently designing certification schemes for the sustainable production of biomass. This paper questions the validity of proposed environmental standards, using the production of Argentine soybean as a case study. The production of soybean production is associated with profound environmental impacts...

  16. The belt of metagabbros of La Pampa: Lower Paleozoic back-arc magmatism in south-central Argentina

    Science.gov (United States)

    Chernicoff, Carlos J.; Zappettini, Eduardo O.; Villar, Luisa M.; Chemale, Farid, Jr.; Hernández, Laura

    2009-12-01

    Combined geological, geochronological, geochemical and geophysical studies have led to identification of a large (˜300 km long, ˜5 km wide) N-S trending belt of metagabbros in the province of La Pampa, south-central Argentina. This belt, though only poorly exposed in the localities of Valle Daza and Sierra de Lonco Vaca, stands out in the geophysical data (aeromagnetics and gravity). Modeling of the aeromagnetic data permits estimation of the geometry of the belt of metagabbros and surrounding rocks. The main rock type exposed is metagabbros with relict magmatic nucleii where layering is preserved. A counterclockwise P-T evolution affected these rocks, i.e., during the Middle Ordovician the protolith reached an initial granulite facies of metamorphism (M1), evolving to amphibolite facies (M2). During the Upper Devonian, a retrograde, greenschist facies metamorphism (M3) partially affected the metagabbros. The whole-rock Sm-Nd data suggest a juvenile source from a depleted mantle, with model ages ranging from 552 to 574 Ma, and positive Epsilon values of 6.51-6.82. A crystallization age of 480 Ma is based on geological considerations, i.e. geochronological data of the host rocks as well as comparisons with the Las Aguilas mafic-ultramafic belt of Sierra de San Luis (central Argentina). The geochemical studies indicate an enriched MORB and back-arc signature. The La Pampa metagabbros are interpreted to be originated as a result of the extension that took place in a back-arc setting coevally with the Famatinian magmatic arc (very poorly exposed in the western part of the study area). The extensional event was 'aborted' by the collision of the Cuyania terrane with Pampia-Gondwana in the Middle Ordovician, causing deformation and metamorphism throughout the arc-back-arc region. The similarities between the La Pampa metagabbros and the mafic-ultramafic Las Aguilas belt of the Sierra de San Luis are very conspicuous, for example, the age (Lower Paleozoic), geochemical

  17. Education in acoustics in Argentina

    Science.gov (United States)

    Miyara, Federico

    2002-11-01

    Over the last decades, education in acoustics (EA) in Argentina has experienced ups and downs due to economic and political issues interfering with long term projects. Unlike other countries, like Chile, where EA has reached maturity in spite of the acoustical industry having shown little development, Argentina has several well-established manufacturers of acoustic materials and equipment but no specific career with a major in acoustics. At the university level, acoustics is taught as a complementary--often elective--course for careers such as architecture, communication engineering, or music. In spite of this there are several research centers with programs covering environmental and community noise, effects of noise on man, acoustic signal processing, musical acoustics and acoustic emission, and several national and international meetings are held each year in which results are communicated and discussed. Several books on a variety of topics such as sound system, architectural acoustics, and noise control have been published as well. Another chapter in EA is technical and vocational education, ranging between secondary and postsecondary levels, with technical training on sound system operation or design. Over the last years there have been several attempts to implement master degrees in acoustics or audio engineering, with little or no success.

  18. Sistema de salud de Argentina The health system of Argentina

    Directory of Open Access Journals (Sweden)

    Mariana Belló

    2011-01-01

    Full Text Available En este artículo se describe el sistema de salud de Argentina, que está compuesto por tres sectores: público, de seguridad social y privado. El sector público está integrado por los ministerios nacional y provincial, y la red de hospitales y centros de salud públicos que prestan atención gratuita a toda persona que lo demande, fundamentalmente a personas sin seguridad social y sin capacidad de pago. Se financia con recursos fiscales y recibe pagos ocasionales de parte del sistema de seguridad social cuando atiende a sus afiliados. El sector del seguro social obligatorio está organizado en torno a las Obras Sociales (OS, que aseguran y prestan servicios a los trabajadores y sus familias. La mayoría de las OS operan a través de contratos con prestadores privados y se financian con contribuciones de los trabajadores y patronales. El sector privado está conformado por profesionales de la salud y establecimientos que atienden a demandantes individuales, a los beneficiarios de las OS y de los seguros privados. Este sector también incluye entidades de seguro voluntario llamadas Empresas de Medicina Prepaga que se financian sobre todo con primas que pagan las familias y/o las empresas. En este trabajo también se describen las innovaciones recientes en el sistema de salud, incluyendo el Programa Remediar.This paper describes the health system of Argentina.This system has three sectors: public, social security and private.The public sector includes the national and provincial ministries as well as the network of public hospitals and primary health care units which provide care to the poor and uninsured population. This sector is financed with taxes and payments made by social security beneficiaries that use public health care facilities. The social security sector or Obras Sociales (OS covers all workers of the formal economy and their families. Most OS operate through contracts with private providers and are financed with payroll

  19. Argentina to fully privatize state owned YPF

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Argentina's Congress has voted to fully privatize state petroleum company Yacimientos Petroliferos Fiscales (YPF), a move the government expects to net at least $8 billion. Despite some political opposition, the vote was 119-10 in favor, with one abstention and opposition party members refusing to participate in the vote. Argentina's President Carlos Menem had threatened to authorize YPF privatization by decree if there was no quorum for a vote. YPF is responsible for 40% of Argentina's oil production. The country h as been self-sufficient in crude since 1982. Current production is 563,472 b/d, and proved reserves of oil and gas are valued at $7 billion

  20. Archean evolution of Enderby Land (Antarctica) and isotope-geochronological evidences for its ancient history

    International Nuclear Information System (INIS)

    Krylov, D.P.; Belyatskij, B.V.

    1987-01-01

    Revew of published isotope-geochronological data on Ender by Land (Antarctica), which is the region of highly metamorphic formations predominant development which includes ancient rock relicts, is presented. Three tectonic-thermal events present the Archeau evolution in the region. Correlation of isotope-geochronological (U-Pb, Rb-Sr, Sm-Nd) data with micro textural processing allows to estimate tectonic-thermal events age: 3000-3100 about 2900 and about 2500 million years. Metamorphism of 3000-3100 million years age has essentially modified all the isotope systems, while model calculations for evolution of U-Pb, Rb-Sr, Sm-Nd systems have shown that rocks primary formation accurred 3500-3900 million years ago

  1. The Potassium-Argon Laser Experiment (KArLE): In Situ Geochronology for Planetary Robotic Missions

    Science.gov (United States)

    Cohen, Barbara

    2016-01-01

    The Potassium (K) - Argon (Ar) Laser Experiment (KArLE) will make in situ noble-gas geochronology measurements aboard planetary robotic landers and roverss. Laser-Induced Breakdown Spectroscopy (LIBS) is used to measure the K abun-dance in a sample and to release its noble gases; the evolved Ar is measured by mass spectrometry (MS); and rela-tive K content is related to absolute Ar abundance by sample mass, determined by optical measurement of the ablated volume. KArLE measures a whole-rock K-Ar age to 10% or better for rocks 2 Ga or older, sufficient to resolve the absolute age of many planetary samples. The LIBS-MS approach is attractive because the analytical components have been flight proven, do not require further technical development, and provide complementary measurements as well as in situ geochronology.

  2. Geochronology of Cenozoic rocks in the Bodie Hills, California and Nevada

    Science.gov (United States)

    Fleck, Robert J.; du Bray, Edward A.; John, David A.; Vikre, Peter G.; Cosca, Michael A.; Snee, Lawrence W.; Box, Stephen E.

    2015-01-01

    The purpose of this report is to present geochronologic data for unaltered volcanic rocks, hydrothermally altered volcanic rocks, and mineral deposits of the Miocene Bodie Hills and Pliocene to Pleistocene Aurora volcanic fields of east-central California and west-central Nevada. Most of the data presented here were derived from samples collected between 2000–13, but some of the geochronologic data, compiled from a variety of sources, pertain to samples collected during prior investigations. New data presented here (tables 1 and 2; Appendixes 1–3) were acquired in three U.S. Geological Survey (USGS) 40Ar/39Ar labs by three different geochronologists: Robert J. Fleck (Menlo Park, CA), Lawrence W. Snee (Denver, CO), and Michael A. Cosca (Denver, CO). Analytical methods and data derived from each of these labs are presented separately.

  3. Contribution to the geochronological pile of the setentrional portion of Ribeira folded belt

    International Nuclear Information System (INIS)

    Batista, J.J.; Kawashita, K.

    1985-01-01

    Six new Rb-Sr isochrons on samples of rocks of the setentrional portion of the Ribeira folded belt are presented and discussed with others geochronological and geological data. The main object of this study is the search of the understanding of the geodynamic evolution of this Region using the Rb-Sr method. The results obtained for the K-Ar and U-Pb, in other papers, are also commented. The integrated analysis of the date deals with the charnocketic, gneissic - migmatitic and magmatic rocks. All the data are refered to the Brasiliano cicle (Upper Precambrian), and thus, the geochronological pattern points out to an important event in the generation of the geologic processes for the brasilian geotectonic unit. (Author) [pt

  4. The geotectonic evolution of the Northeastern Minas Gerais, based in geochronological interpretation

    International Nuclear Information System (INIS)

    Siga Junior, O.

    1986-01-01

    This work tries to show the potential of the Rb-Sr, K-Ar, Pb-Pb and U-Pb methods applied to basic geological maping. The different interpretative values of these methodologies contribute to the understanding of the tectonic processes developed in the southeastern border of the Sao Francisco Craton (northeastern Minas Gerais and southern Bahia). The geochronological data for this region represents sampling of the several lithological units characterized and corresponds to about 230 determinations. The radiometric age distribution pattern together with other geological information suggest the subdivision into two main geochronological domains: the external Brazilian domain (at the western portion) and the internal Brazilian domain (at the center-eastern part). (author) [pt

  5. Measured radon inside housings the Republic Argentina

    International Nuclear Information System (INIS)

    Canoba, A.; Arnaud, M.; Lopez, F.; Oliveira, A.A.

    1998-01-01

    They have been measured the radon concentration in houses in different city's in Argentina Republic. For they were used it as method mensuration detectors appearances nuclear detecting electrets and detectors based on the adsorption radon in activated carbon

  6. Nuclear Data in Argentina (1992 -1993)

    International Nuclear Information System (INIS)

    Ricabarra, G. H.

    1993-03-01

    A progress report of nuclear data research in Argentina is given for the years 1992/1993, including the WIMS nuclear data library update project, and measurements and evaluations of selected neutron induced nuclear reactions. (author)

  7. Eaglet property, southeastern British Columbia: Re-Os geochronology, sulphur isotopes, and thermobarometry

    Czech Academy of Sciences Publication Activity Database

    Hora, Z. D.; Stein, H.; Žák, Karel; Dobeš, P.

    2018-01-01

    Roč. 2017, č. 1 (2018), s. 157-166 ISSN 0381-243X Institutional support: RVO:67985831 Keywords : Eaglet deposit * MINFILE 093A 046 * fluorite * celestite * molybdenite * sulphur isotopes * Re-Os geochronology * fluid inclusion microthermobarometry Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology http://cmscontent.nrs.gov.bc.ca/geoscience/PublicationsCatalogue/Fieldwork/Documents/2017/P2018-1.pdf

  8. Biomarkers in sediments. The racemization/epiremitation of amino acids like tool in geochronology and paleothermometrics

    International Nuclear Information System (INIS)

    Torres, T.; Llamas, F. J.; Canoira, L.; Garcia-Alonso, P.; Ortiz, J. E.

    1999-01-01

    The study of amino acids as biomarkers in sediments has become a necessary methodology and tool for the analysis of palaeoenvironmental conditions and, therefore, of climatic evolution in the past. Research based on the selection and analysis of geological biomarkers, and more specifically activities relating to the racemization/epimerization of amino acids, makes it possible to obtain the geochronological and photoelectrochemical data required to establish different hypotheses for Long-Term Performance Assessment of a repository for high level radioactive wastes

  9. Breaking through the uncertainty ceiling in LA-ICP-MS U-Pb geochronology

    Science.gov (United States)

    Horstwood, M.

    2016-12-01

    Sources of systematic uncertainty associated with session-to-session bias are the dominant contributor to the 2% (2s) uncertainty ceiling that currently limits the accuracy of LA-ICP-MS U-Pb geochronology. Sources include differential downhole fractionation (LIEF), `matrix effects' and ablation volume differences, which result in irreproducibility of the same reference material across sessions. Current mitigation methods include correcting for LIEF mathematically, using matrix-matched reference materials, annealing material to reduce or eliminate radiation damage effects and tuning for robust plasma conditions. Reducing the depth and volume of ablation can also mitigate these problems and should contribute to the reduction of the uncertainty ceiling. Reducing analysed volume leads to increased detection efficiency, reduced matrix-effects, eliminates LIEF, obviates ablation rate differences and reduces the likelihood of intercepting complex growth zones with depth, thereby apparently improving material homogeneity. High detection efficiencies (% level) and low sampling volumes (20um box, 1-2um deep) can now be achieved using MC-ICP-MS such that low volume ablations should be considered part of the toolbox of methods targeted at improving the reproducibility of LA-ICP-MS U-Pb geochronology. In combination with other strategies these improvements should be feasible on any ICP platform. However, reducing the volume of analysis reduces detected counts and requires a change of analytical approach in order to mitigate this. Appropriate strategies may include the use of high efficiency cell and torch technologies and the optimisation of acquisition protocols and data handling techniques such as condensing signal peaks, using log ratios and total signal integration. The tools required to break the 2% (2s) uncertainty ceiling in LA-ICP-MS U-Pb geochronology are likely now known but require a coherent strategy and change of approach to combine their implementation and realise

  10. Geochronology database for New Zealand rocks (2nd edition) : 1961-1999

    International Nuclear Information System (INIS)

    Nathan, S.; Thurlow, C.; Warnes, P.N.; Zucchetto, R.

    2000-01-01

    A bibliography and database of radiometric ages on rocks in the New Zealand region, published between 1961-1999 has been prepared as a joint project between the Geochemical, Isotopic and Geochronology Database of the Geological Society of New Zealand and the Geologic Mapping Programme of the Institute of Geological and Nuclear Sciences. Over 3800 entries are included. Separate tables also document over 200 K-Ar ages that have not been previously published. (author). 237 refs

  11. Geochemical geochronology and genesis of granite from Coronel Murta, Northeast of Minas Gerais, Brazil

    International Nuclear Information System (INIS)

    Soares, A.C.P.; Siga Junior, O.

    1987-01-01

    Geological, petrographic, geochemical (including rare-earth elements) and geochronological data of the Coronel Murta (Northeast Minas Gerais State) post-tectonic intrusive alkalic granites were summarized in order to discuss their genesis. This paper shows that Coronel Murta granites were generated by anatexis of dominantly metasedimentary rocks, in an ensialic environment, as the late results of an intraplate A-type subduction during the Brazilian Cycle. (author) [pt

  12. Development of the Potassium-Argon Laser Experiment (KArLE) Instrument for In Situ Geochronology

    Science.gov (United States)

    Cohen, Barbara A.; Li, Z.-H.; Miller, J. S.; Brinckerhoff, W. B.; Clegg, S. M.; Mahaffy, P. R.; Swindle, T. D.; Wiens, R. C.

    2012-01-01

    Absolute dating of planetary samples is an essential tool to establish the chronology of geological events, including crystallization history, magmatic evolution, and alteration. Traditionally, geochronology has only been accomplishable on samples from dedicated sample return missions or meteorites. The capability for in situ geochronology is highly desired, because it will allow one-way planetary missions to perform dating of large numbers of samples. The success of an in situ geochronology package will not only yield data on absolute ages, but can also complement sample return missions by identifying the most interesting rocks to cache and/or return to Earth. In situ dating instruments have been proposed, but none have yet reached TRL 6 because the required high-resolution isotopic measurements are very challenging. Our team is now addressing this challenge by developing the Potassium (K) - Argon Laser Experiment (KArLE) under the NASA Planetary Instrument Definition and Development Program (PIDDP), building on previous work to develop a K-Ar in situ instrument [1]. KArLE uses a combination of several flight-proven components that enable accurate K-Ar isochron dating of planetary rocks. KArLE will ablate a rock sample, determine the K in the plasma state using laser-induced breakdown spectroscopy (LIBS), measure the liberated Ar using quadrupole mass spectrometry (QMS), and relate the two by the volume of the ablated pit using an optical method such as a vertical scanning interferometer (VSI). Our preliminary work indicates that the KArLE instrument will be capable of determining the age of several kinds of planetary samples to +/-100 Myr, sufficient to address a wide range of geochronology problems in planetary science.

  13. Pre-Alpine evolution of the Seckau Complex (Austroalpine basement/Eastern Alps): Constraints from in-situ LA-ICP-MS Usbnd Pb zircon geochronology

    Science.gov (United States)

    Mandl, Magdalena; Kurz, Walter; Hauzenberger, Christoph; Fritz, Harald; Klötzli, Urs; Schuster, Ralf

    2018-01-01

    The Variscan European Belt is a complex orogen with its southern margin partly obscured by Alpine tectonics and metamorphism. We present a study of one of the units, the Seckau Complex, that constitute the southern part of the Variscan European Belt in the Eastern Alps in order to clarify its origin, age and lithostratigraphy. The magmatic and geochronological evolution of this Complex in the northwestern part of the Seckau Nappe (as part of the Austroalpine Silvretta-Seckau Nappe System) was investigated by zircon Usbnd Pb dating of paragneisses and metagranitoids coupled with petrological and geochemical data. This reveals the distinction of three newly defined lithostratigraphic/lithodemic sub-units: (1) Glaneck Metamorphic Suite, (2) Hochreichart Plutonic Suite and (3) Hintertal Plutonic Suite. The Glaneck Metamorphic Suite is mainly composed of fine-grained paragneisses that yield Usbnd Pb zircon ages in the range between 2.7 Ga and 2.0 Ga, as well as concordia ages from 572 ± 7 Ma to 559 ± 11 Ma. All of these ages are interpreted as detrital zircon ages originating from an igneous source. The paragneisses are the host rock for the large volumes of metagranitoids of the Hochreichart Plutonic Suite and the Hintertal Plutonic Suite. The Hochreichart Plutonic Suite comprises highly fractionated melts with mainly S-type characteristics and late Cambrian to Early Ordovician Usbnd Pb zircon ages (508 ± 9 Ma to 486 ± 9 Ma), interpreted as magmatic protolith ages. The Hintertal Plutonic Suite is composed of metagranitoids with Late Devonian to early Carboniferous (365 ± 11 Ma and 331 ± 10 Ma) protolith ages, that intruded during an early phase of the Variscan tectonometamorphic event. The metagranitoids of the Hintertal Plutonic Suites define a magmatic fractionation trend, seen in variable Rb/Sr ratios. On this base they can be further subdivided into (a) the Griessstein Pluton characterized by S-type metagranitoids and (b) the Pletzen Pluton distinguished by

  14. Transnational Crime Fictions and Argentina's Criminal State

    OpenAIRE

    Caballero, Juan

    2013-01-01

    My dissertation, titled "Transnational Crime Fictions and Argentina's Criminal State," proposes a new understanding of the dictatorship novels of Ricardo Piglia, Juan José Saer, and Manuel Puig grounded in their shared appropriation from popular crime fiction. Across the 1940's, 50's, and 60's, a wide range of popular crime fiction was translated, written, theorized, printed and reprinted in Argentina, and these popular genres grew steadily in readership, visibility, and cultural legitimacy....

  15. Update on women in physics in Argentina

    Science.gov (United States)

    Brudny, Vera; Lagorio, Cecilia; Frechero, Marisa; Tamarit, Francisco

    2013-03-01

    Data collected 10 years ago in Argentina concluded that women in physics were underrepresented in many instances and that a "crystal ceiling" was firmly in place. We have collected updated data for several indicators and compared them with those obtained 10 years ago. Although there is not a clear conclusion to be drawn from this comparison, we try to explain the results within the framework of the changes in scientific policies in Argentina.

  16. Update on women in physics in Argentina

    OpenAIRE

    Brudny, Vera Leonor; Lagorio, Cecilia; Frechero, Marisa Alejandra; Tamarit, Francisco

    2016-01-01

    Data collected 10 years ago in Argentina concluded that women in physics were underrepresented in many instances and that a “crystal ceiling” was firmly in place. We have collected updated data for several indicators and compared them with those obtained 10 years ago. Although there is not a clear conclusion to be drawn from this comparison, we try to explain the results within the framework of the changes in scientific policies in Argentina. Fil: Brudny, Vera Leonor. Universidad de Buenos...

  17. China, Argentina agree to further strategic ties

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    According to Xinhua,China and Argentina have agreed to further enhance mutual trust and their strategic partnership as the two emerging economies are playing an increasingly important role in the world arena.“China will work with Argentina to strengthen strategic mutual trust,expand cooperation and coordination within multilateral frameworks in order to promote bilateral ties and benefit the two peoples,” Vice President Xi Jinping told Argentine Foreign Minister Hector Timerman on September 9.

  18. Poverty and Health in Argentina

    Directory of Open Access Journals (Sweden)

    Maria Alejandra Silva

    2009-06-01

    Full Text Available This article examines health conditions in the rural areas of Central Argentina, the country’s main region for soy-bean production and export. Health conditions are analyzed through the concepts of emerging and re-emerging diseases in a context of increasing poverty. Data on poverty and health was obtained from both primary sources (trade union, government officials, rural doctors and the South Watch/FA/FODEPAL/UNR working group and secondary sources (IPEC/INDEC, IDESA, Consultora Equis, the Argentine Ministry of Employment, ILO, the Ministry of Health, the Ministry of the Environment, toxicology centers and rural doctors. Analysis of rural health conditions gives cause for concern. There is evidence of deterioration in the social determinants of health such as an increase in rural and urban poverty associated with informal employment and child labor. At the same time lack of government epidemiological and toxicological data appears to hide or distort the reality of health conditions.

  19. An Energy Overview of Argentina

    International Nuclear Information System (INIS)

    2003-01-01

    The DOE Office of Fossil Energy is maintaining a web site that is meant to provide useful business- and energy-related information about countries and regions of the world for exporters, project developers, and researchers. The site consists of more than 130 country pages (organized into seven different world regions), with each country page having its own set of links to information sources about that country. There are also more than 30 Country Energy Overviews at the web site -- each of these is a comprehensive review of a specific country's entire energy situation, including sections on Energy Policy, Oil, Natural Gas, Coal, Hydroelectric/Renewables, Nuclear Power, Energy Transmission Infrastructure, Electricity, Electric Industry Overview, Environmental Activities, Privatization, Trade, and Economic Situation. The specific country highlighted in this Country Energy Overview is Argentina. The site is designed to be dynamic. Updates to the overviews will be made as need and resources permit

  20. Nuclear security standard: Argentina approach

    International Nuclear Information System (INIS)

    Bonet Duran, Stella M.; Rodriguez, Carlos E.; Menossi, Sergio A.; Serdeiro, Nelida H.

    2007-01-01

    Argentina has a comprehensive regulatory system designed to assure the security and safety of radioactive sources, which has been in place for more than fifty years. In 1989 the Radiation Protection and Nuclear Safety branch of the National Atomic Energy Commission created the 'Council of Physical Protection of Nuclear Materials and Installations' (CAPFMIN). This Council published in 1992 a Physical Protection Standard based on a deep and careful analysis of INFCIRC 225/Rev.2 including topics like 'sabotage scenario'. Since then, the world's scenario has changed, and some concepts like 'design basis threat', 'detection, delay and response', 'performance approach and prescriptive approach', have been applied to the design of physical protection systems in facilities other than nuclear installations. In Argentina, radioactive sources are widely used in medical and industrial applications with more than 1,600 facilities controlled by the Nuclear Regulatory Authority (in spanish ARN). During 2005, measures like 'access control', 'timely detection of intruder', 'background checks', and 'security plan', were required by ARN for implementation in facilities with radioactive sources. To 'close the cycle' the next step is to produce a regulatory standard based on the operational experience acquired during 2005. ARN has developed a set of criteria for including them in a new standard on security of radioactive materials. Besides, a specific Regulatory Guide is being prepared to help licensees of facilities in design a security system and to fulfill the 'Design of Security System Questionnaire'. The present paper describes the proposed Standard on Security of Radioactive Sources and the draft of the Nuclear Security Regulatory Guidance, based on our regulatory experience and the latest international recommendations. (author)

  1. 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...

  2. Argentina

    Directory of Open Access Journals (Sweden)

    Guillermina Fernández Zambón

    2005-01-01

    Full Text Available La actividad industrial, de cualquier época, tiene una gran importancia para el hombre, pues al igual que el resto de los procesos económicos, es el reflejo del accionar cotidiano de la sociedad sobre el espacio. Considerando esto, el presente articulo tiene como objetivo presentar al patrimonio industrial como recurso para organizar rutas turísticas que permitan en algunos casos recuperar espacios industriales abandonados o usar establecimientos industriales en funcionamiento pero que pueden incorporarse a este tipo de desarrollo turístico. La creación de rutas turísticas puede permitir la reactivación de las economías locales, por constituirse en definitiva en una nueva actividad económica. Para lograr esto es necesario articular el sector público y el privado. De esta forma es posible, a través de la creación de rutas turísticas del patrimonio industrial, generar un desarrollo turístico local sustentable.

  3. 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

  4. 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.

  5. 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.

  6. Control of nuclear materials and materials in Argentina

    International Nuclear Information System (INIS)

    Arbor G, A.; Fernandes M, S.

    1988-01-01

    A general view about the safeguards activities in Argentina is presented. The national system of accounting for and control of nuclear materials is described. The safeguards agreement signed by Argentina are presented. (E.G.) [pt

  7. Psychiatry and humanism in Argentina.

    Science.gov (United States)

    Niño Amieva, Alejandra

    2016-04-01

    The authors of the present selection of Latin American Psychiatry texts were characterized by a common deep humanistic attitude. These prolific writers were able to establish or extend the scope of the discipline in which they chose to act, questioning the establishment of rigid boundaries within the framework of a rigorous epistemological reflection. Thus the systematizing spirit of Jose Ingenieros' in the context of positivist evolutionism, resulted in the act of founding a discipline that integrated the biological and the social. In the case of Guillermo Vidal his conception of mental health went beyond the biomedical to consider psychotherapies as an emotional commitment, continence and empathic understanding; with regard to César Cabral his formation and extensive clinical practice resulted in a work defined by the inquiring into the theoretical concepts underlying Psychiatry and Clinical Psychology. This brief selection does not exhaust the issues or the level of ideas and discussions of Psychiatry in Argentina, but constitutes a textual corpus representative of a disciplinary conception understood as scientific and humanistic endeavor.

  8. Argentina chiama Italia: Friuli risponde

    Directory of Open Access Journals (Sweden)

    Silvana Serafin

    2010-03-01

    Full Text Available The study analyzes the migratory waves from Friuli which, from the 1870s up to the post-World War II years, extensively moved towards Argentina, settling in the areas around the cities of Santa Fe, Cordoba, Entre Ríos, Chaco and Buenos Aires, but reaching also regions as far away as Patagonia. The accurate and well diffused net of the Fogolār Furlan, besides its function as friendly society, also provides to the promulgation of ancient traditions and mores among the new generations, transmitting on to them the cultural, linguistic and ethnic memory of the motherland. Epistles, tales, novels and poems form a paideia which is thus constantly being enlivened, eveng among those who assumed Argentinian nationality or were born in the country. Of utmost interest is, therefore, the resulting literary corpus, representing as it does a renewed search for identity in the form of a dialogue with the world, extending itself well beyond the contingency of boundaries and transmitting the universal essence of logos.

  9. 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

  10. The nuclear research centre at Bariloche, Argentina

    International Nuclear Information System (INIS)

    Abriata, J.P.

    2001-01-01

    The nuclear research centre at Bariloche (CAB) is one of the four centres under the Atomic Energy Commission of Argentina (CNEA). The research programme of CAB addresses various issues like nuclear reactor development, nuclear fuel and fuel cycle, applications of radioisotopes and radiation, and waste management. There is also a basic nuclear science component. The human resource development in the areas of physics and nuclear engineering is done in an associated Balseiro Institute which has undergraduate and graduate programmes as well as doctoral and postdoctoral research. The Centre interacts well with the society and provides services in the nuclear area. It has a close interaction with the nuclear sector of Argentina as also with many international organisations. Regulatory control over the Centre is carried out by the Nuclear Regulatory Authority of Argentina. (author)

  11. 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

  12. Geology and geochronology of Cardoso Island, in the southeastern coast of Sao Paulo State

    International Nuclear Information System (INIS)

    Weber, Werner

    1998-01-01

    This aim of work is the geological and geochronological study of rocks cropping out on Cardoso Island, on the southeastern coast of Sao Paulo States, close to be boundary with Parana State. The Island with an area of about 151 km 2 is a protected area administered by the Forest Institute of Environment Secretariat of the State of Sao Paulo. It is mountanious, with a peak at 814 m, and is covered by dense Mata Atlantica vegetation. The terrains which compose the island are mainly an igneous complex with light grey leucocratic, inequigranular, medium - to coarse-grained syenites. The predominant Tres Irmaos Syenite (STI), composed of pyroxene, hornblende, and perthitic to mesoperthitic microcline, has a magmatic flow structures, and is cut by the Cambriu alkali-feldspar Granites (GC), which is pinkish grey, leucocratic and medium-grained. Geochemical analysis of STI and GC demonstrate their meta luminous alkaline nature and late-orogenic to an orogenic character. The geochronological results suggest that the bodies were formed between 620 and 570 My according to the U-Pb method in zircons, with cooling between 597 and 531 My (K-Ar in amphiboles). Whole rock Sm-Nd analysis yield T DM ages in the Meso and Paleoproterozoic (1.200 - 2.200 My). belt of low grade meta sedimentary rocks occurs in the northern part of the island. Quartz schist, quartz-mica schist and mica-quartz schist, often containing andaluzite and cordierite, predominate. The geochemical and geochronological data suggest that the sources of the metasediments were andesites of continental arc whose protolities separated from the mantle during the Paleoproterozoic, between 1.800 and 2.200 My. These metasediments probably continue on the continent in the Taquari region and extend southwards in narrow strips between the granitoids of the Paranagua Domain. Although quaternary deposits are expressive, they were not studied in details since they were not the objectives of this study. (author)

  13. Petrology and geochemistry of the marbles and calcosilicated rocks from Ipira, Bahia - Brazil

    International Nuclear Information System (INIS)

    Oliveira, M.A.F.T. de.

    1976-01-01

    This work explains a study of marbles and diopsitites from Serra das Panelas, Ipira, Bahia, Brazil. Petrographic analysis, chemistry some elements, trace elements and rare earths, isotopic analysis of Strontium, carbon and oxigen, and geochronological determinations were done. The ages founded correspond to Transamazonic Orogenetic cicle, with Archean age, confirmed by the 18 O values found, which give to marble, ages about 2.500 my. The mineralogy and the texture give to marble an invulgar aspect, making a confusion with carbonate. The petrochemical data and the geochemistry of 13 C and 18 O isotopes showed that the marble and diopsitites was formed from the old marine carbonates. The geochemistry of rare earth suggests a strong correlation with carbonitic and alkaline rocks. An hybrid origem to this rocks is proposed. (C.D.G.) [pt

  14. Argentina's YPF hones in on privatization

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    This paper reports on Argentina's push to privatize and attract more foreign investment to its petroleum sector which continues to gather momentum. The Argentine government plans by year end 1992 to sell unprofitable assets of Yacimientos Petroliferos Fiscales, then sell as much as 50% of the state oil company through an international stock offering. If privatization proceeds as expected, YPF Pres. Jose Estenssoro the, the company's stock will be offered to private investors early in 1993. The company was founded in 1922. By March 1992, Argentina also will begin selling all assets of state owned Gas del Estado (GDE) through an international bidding process expected to take about 18 months

  15. Communications received from Argentina and Brazil

    International Nuclear Information System (INIS)

    1988-05-01

    The document reproduces the Joint Declaration on Nuclear Policy signed by the Presidents of Argentina and Brazil on 30 November 1985, the Protocol on Nuclear Co-operation between Argentina and Brazil signed on 10 December 1986, the Joint Declaration on Nuclear Policy signed by the two Presidents on 10 December 1986, the Joint Declaration on Nuclear Policy signed by the two Presidents on 17 July 1987 and the Joint Declaration on Nuclear Policy (IPERO Declaration) signed by the two Presidents on 8 April 1988

  16. Geochronology of sedimentary and metasedimentary Precambrian rocks of the West African craton

    International Nuclear Information System (INIS)

    Clauer, N.; Jeannette, D.; Trompette, R.

    1982-01-01

    This contribution summarizes current knowledge of the geochronology of the Upper Proterozoic sedimentary rocks covering the West African craton. This was done by using direct dating methods. Correlations between the northern edge of the Tindouf basin and the northern and southern part of the Taoudeni basin, as well as the Volta basin, are proposed. Tectonic, volcanic and thermal activities in connection with the Pan-African orogeny are recorded only around the craton. They induced either sedimentation lacks in Morocco or sedimentation excesses in Hoggar. Unsolved problems such as the precise stratigraphic position of the uppermost Proterozoic tillitic episode and the correlation within the Moroccan Anti-Atlas are also raised. (Auth.)

  17. Goethite (U–Th)/He geochronology and precipitation mechanisms during weathering of basalts

    OpenAIRE

    Riffel, Silvana B.; Vasconcelos, Paulo M.; Carmo, Isabela O.; Farley, Kenneth A.

    2016-01-01

    (U–Th)/He geochronology of 33 goethite grains from in situ ferruginous duricrusts overlying the Paraná flood basalt in the Guarapuava region, Paraná, Brazil, reveals ages ranging from 3.6 ± 0.4 to 0.4 ± 0.1 Ma. Thirty-one grains from detrital fragments of ferruginous duricrust yield ages in the 6.2 ± 0.6 to 0.7 ± 0.1 Ma range. The results show that goethites from detrital blocks are generally older than those from the in situ ferruginous layers and that all the goethites from the Guarapuava s...

  18. Geology, petrography and geochronology of meridional and oriental regions from Morungaba complex, SP

    International Nuclear Information System (INIS)

    Vlach, S.R.F.

    1985-01-01

    The Morungaba Granitoid Complex, covering about 330 km 2 , crops out as an elongate irregular Massif trending SW-NE, in the southeast part of the State of Sao Paulo, southeast Brazil. Major constituents are biotite granitoids with subordinate diorites. Over thirty facies types, each with distinctive structural-petrographic features, were recognized during detailed mapping of part of the Massif (about 200 km 2 ), and mapped as groups of facies. Geochronological Rb/Sr data for several groups of associated facies are also presented. (author)

  19. Half-lives of radionuclides used in nuclear geochronology and cosmochronology (evaluated data)

    International Nuclear Information System (INIS)

    Chechev, V.P.

    2002-01-01

    Evaluated half-life values are given for the radionuclides 26 Al, 40 K, 53 Mn, 60 Fe, 87 Rb, 93 Zr, 98 Tc, 107 Pd, 129 I, 135 Cs, 146 Sm, 176 Lu, 182 Hf, 187 Re, 205 Pb, 232 Th, 235 U, 238 U, 244 Pu and 247 Cm. These were obtained from an analysis of published information up to 2001. These half-lives are used in geochronology and cosmochronology to determine different radiometric ages in the history of the earth, solar system and galaxy. (author)

  20. Geochronology and structuring of the Ceara State: Borborema Province northwestern part, NE Brazil

    International Nuclear Information System (INIS)

    Fetter, A.; Van Schmus, W.R.; Santos, Ticiano J. Saraiva dos; Arthaud, M.; Nogueira Neto, J.

    1997-01-01

    The work confirms that the geochronological new data U/Pb in zircon and Samarium/Neodymium from the Ceara State furnished a refined chronology of the geological activity in the NW part of the Borborema Province, indicating an evolutive history since 2,78 Ga and 532 Ma. Furthermore, these data facilitated the different crust domain outlines in the region, putting age maximum limits in the pre-brasilianas supracrusts rocks deposition, and evidencing the epoch and duration of the Brasiliano magmatism and metamorphism in the northwest part of the State

  1. Geochronological correlation of the late Precambrian sequences on and around the stable zones of Equatorial Africa

    International Nuclear Information System (INIS)

    Cahen, L.

    1982-01-01

    Very few radiometric age determinations have a bearing on the late Precambrian sequences of the stable zones of Equatorial Africa. A geochronological correlation of these sequences must therefore rest upon a compilation of ages from these stable zones and the corresponding mobile zones. About 15 ages of varying precision more or less well tied up with the stratigraphical sequences, together with results of the study of stromatolite assemblages allow a provisional correlation to be made. One conclusion of this correlation is that most mixtites surrounding the Congo basin are in a 950 +- 50 Ma age bracket and are presumably to be correlated. (Auth.)

  2. Paleoclimates and geomorphological evolution of the Carajas region: geochemical and geochronological evidence

    International Nuclear Information System (INIS)

    Vasconcelos, P.M.

    1996-01-01

    Based on the geochronological results, on the petrographical and geochemical observations and considering the experimental evidences that suggests a great influence of the organic processes in the Manganese geochemistry it's possible to conclude that the dissolution and reprecipitation events of the Manganese oxides in the Carajas region, Para State, Brazil, represents humid and hot periods in the geological history of the region. The weathering dating furnishes information about the continental evolution in the Mesozoic/Cenozoic, difficult or impossible to determine by another methods

  3. Geological evolution of the center-southern portion of the Guyana shield based on the geochemical, geochronological and isotopic studies of paleoproterozoic granitoids from southeastern Roraima, Brazil

    International Nuclear Information System (INIS)

    Almeida, Marcelo Esteves

    2006-01-01

    This study focuses the granitoids of center-southern portion of Guyana Shield, southeastern Roraima, Brazil. The region is characterized by two tectonic-stratigraphic domains, named as Central Guyana (GCD) and Uatuma-Anaua (UAD) and located probably in the limits of geochronological provinces (e.g. Ventuari-Tapajos or Tapajos-Parima, Central Amazonian and Maroni-Itacaiunas or Transamazon). The aim this doctoral thesis is to provide new petrological and lithostratigraphic constraints on the granitoid rocks and contribute to a better understanding of the origin and geo dynamic evolution of Guyana Shield. The GCD is only locally studied near to the UAD boundary, and new geological data and two single zircon Pb-evaporation ages in mylonitic biotite granodiorite (1.89 Ga) and foliated hastingsite-biotite granite (1.72 Ga) are presented. These ages of the protholiths contrast with the lithostratigraphic picture in the other areas of Cd (1.96-1.93 Ga). Regional mapping, petrography, geochemistry and zircon geochronology carried out in the Urad have showed widespread Paleoproterozoic calc-alkaline granitic magmatism. These granitoid rocks are distributed into several magmatic associations with different Paleoproterozoic (1.97-1.89 Ga) ages, structural and geochemical affinities. Detailed mapping, petrographic and geochronological studies have distinguished two main sub domains in the UAD. In the northern UAD, the high-K calc-alkaline Martins Pereira (1.97 Ga) and Serra Dourada S-type granites (1.96 Ga) are affected by NE-SW and E-W ductile dextral shear-zones, showing coexistence of magmatic and deformational fabrics related to heterogeneous deformation. Inliers of basement (2.03 Ga) crop out northeast of this area, and are formed by meta volcano-sedimentary sequence (Cauarane Group) and TTG-like calc-alkaline association (Anaua Complex). Xenoliths of meta diorites (Anaua Complex) and para gneisses (Cauarane Group) reinforce the intrusive character of Martins Pereira

  4. 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

  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. 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.

  7. Operating practical experience at Argentina; Experiencia practica operativa en la Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Quihillalt, Oscar [Nucleoelectria Argentina S.A., Buenos Aires (Argentina)

    1998-12-31

    Operating experiences of Atucha-1 and Embalse Nuclear Power Plants were discussed in this work. The technical and economic aspects, such as reliability, availability, personnel training, operating costs, prices and market, which exercise influence upon Argentina nuclear energy policy, mainly on the power electric generation by nuclear power plants were considered. Finally the current status of the nucleoelectric sector in Argentina and forecasting were analysed. 3 figs., 5 tabs.

  8. 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

  9. The Politics of Human Rights in Argentina

    OpenAIRE

    Brysk, Alison

    2013-01-01

    Revised edition of 1994 out-of-print Stanford University Press study of human rights protest, social change, and democratization in Argentina.  A symbolic politics analysis of the truth commission, trials, and policy reform in Latin America's most sweeping transition of the 1980's.

  10. Argentina - Women Weaving Equitable Gender Relations

    OpenAIRE

    Stubbs, Josefina

    2008-01-01

    In 2001, after a long period of recession, Argentina faced the greatest economic, political, and institutional crisis in its history. Unemployment reached levels nearing 18 percent and the poverty rate reached a peak of 58 percent in 2002, increasing twofold the number of people living the poverty line and impacting in a disproportionate manner the most vulnerable and poverty stricken fami...

  11. Agua potable y saneamiento en la Argentina

    OpenAIRE

    Auge, Miguel

    2007-01-01

    Este trabajo fue presentado originalmente en el Foro Regional del Agua, con el título “Problemática del Acceso al Agua Potable y al Saneamiento en Argentina”. Dicho foro, organizado por la Defensoría del Pueblo de la Nación Argentina, se desarrolló en Córdoba, en mayo del 2007.

  12. Argentina and Brazil's Relations to the EU

    DEFF Research Database (Denmark)

    Christensen, Steen Fryba

    Analysen diskuterer Argentina og Brasiliens relationer til EU i nyere tid med udgangspunkt i forhandlingerne om en associeringsaftale mellem EU og Mercosur, der igangsattes efter underskrivelsen af en bi-regional rammeaftale i 1995. Fokus er i særlig grad på, hvordan disse relationer bedst forstås...

  13. Sudden death syndrome of soybean in Argentina

    Science.gov (United States)

    Sudden death syndrome (SDS) is one of the most common and widely spread root disease affecting soybean [Glycine max (L.) Merr.] in Argentina where it is an economically important crop. This disease was first discovered in this country in 1992 in the Pampas Region, and the following year in Northwest...

  14. Payenia volcanic province, southern Mendoza, Argentina

    DEFF Research Database (Denmark)

    Søager, Nina; Holm, Paul Martin; Llambias, Eduardo Jorge

    2013-01-01

    The Pleistocene to Holocene Payenia volcanic province is a backarc region of 60,000 km2 in Mendoza, Argentina, which is dominated by transitional to alkaline basalts and trachybasalts. We present major and trace element compositions of 139 rocks from this area of which the majority are basaltic...

  15. Argentina : Gender Equity in the Private Sector

    OpenAIRE

    World Bank

    2010-01-01

    First tested in Mexico in 2003, and most recently applied in 2009 in Argentina, the World Bank has developed a model to incorporate gender equity into private sector organizations while simultaneously enhancing their business. Under the model, participating organizations conduct a self-diagnosis to identify gender biases and gaps in the operations. This baseline is then used to create and ...

  16. Applications of dendrochronology and sediment geochronology to establish reference episodes for evaluations of environmental radioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Waugh, W.J.; Carroll, J.; Abraham, J.D.; Landeen, D.S. [Roy F. Weston, Inc., U.S. Department of Energy, Grand Junction Office, 2597 B 3/4 Road, Grand Junction, CO 81503 (United States)

    1998-12-01

    Dendrochronology and sediment geochronology have been used to demonstrate retrospective monitoring of environmental radioactivity at United States Department of Energy (DOE) sites. {sup 14}C in annual growth rings of sagebrush preserved the temporal and spatial patterns of {sup 14}C resulting from dispersion downwind of a nuclear fuel processing facility at the Hanford Site in Washington State. As far as 10 km downwind of the facility, {sup 14}C concentrations were significantly higher in growth rings formed during a fuel processing episode than in rings produced during preoperational or postoperational episodes. An episode of uranium mill tailings deposition in pond sediments at the Grand Junction Office in Colorado was reconstructed using {sup 210}Pb geochronology constrained by a marker of peak {sup 137}Cs fallout. Uranium concentrations in ponds sediments deposited after the processing episode provide a reasonable cleanup standard. These reference episodes of environmental radioactivity reconstructed from measurements taken within contaminated environments can improve or replace reference area data as baseline information for dose reconstructions, risk assessments, and the establishment of cleanup standards. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  17. Applications of dendrochronology and sediment geochronology to establish reference episodes for evaluations of environmental radioactivity

    International Nuclear Information System (INIS)

    Waugh, W.J.; Carroll, J.; Abraham, J.D.; Landeen, D.S.

    1998-01-01

    Dendrochronology and sediment geochronology have been used to demonstrate retrospective monitoring of environmental radioactivity at United States Department of Energy (DOE) sites. 14 C in annual growth rings of sagebrush preserved the temporal and spatial patterns of 14 C resulting from dispersion downwind of a nuclear fuel processing facility at the Hanford Site in Washington State. As far as 10 km downwind of the facility, 14 C concentrations were significantly higher in growth rings formed during a fuel processing episode than in rings produced during preoperational or postoperational episodes. An episode of uranium mill tailings deposition in pond sediments at the Grand Junction Office in Colorado was reconstructed using 210 Pb geochronology constrained by a marker of peak 137 Cs fallout. Uranium concentrations in ponds sediments deposited after the processing episode provide a reasonable cleanup standard. These reference episodes of environmental radioactivity reconstructed from measurements taken within contaminated environments can improve or replace reference area data as baseline information for dose reconstructions, risk assessments, and the establishment of cleanup standards. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  18. 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...

  19. SRTM Anaglyph: Las Bayas, Argentina

    Science.gov (United States)

    2001-01-01

    The interplay of volcanism, stream erosion and landslides is evident in this Shuttle Radar Topography Mission view of the eastern flank of the Andes Mountains, southeast of San Carlos de Bariloche, Argentina. Older lava flows emanating from the Andes once covered much of this area. Younger, local volcanoes (seen here as small peaks) then covered parts of the area with fresh, erosion resistant flows (seen here as very smooth surfaces). Subsequent erosion has created fine patterns on the older surfaces (bottom of the image) and bolder, irregular patterns through and around the younger surfaces (upper center and right center). Meanwhile, where a large stream immediately borders the resistant plateau (center of the image), lateral erosion has undercut the resistant plateau causing slivers of it to fall into the stream channel. This scene well illustrate show topographic data alone can reveal some aspects of recent geologic history.This anaglyph was produced by first shading a preliminary elevation model from data acquired by the Shuttle Radar Topography Mission. The stereoscopic effect was then created by generating two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter.Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on February 11, 2000. The mission used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar that flew twice on the Space Shuttle Endeavour in 1994. The Shuttle Radar Topography Mission was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking

  20. [Adult mortality differentials in Argentina].

    Science.gov (United States)

    Rofman, R

    1994-06-01

    Adult mortality differentials in Argentina are estimated and analyzed using data from the National Social Security Administration. The study of adult mortality has attracted little attention in developing countries because of the scarcity of reliable statistics and the greater importance assigned to demographic phenomena traditionally associated with development, such as infant mortality and fertility. A sample of 39,421 records of retired persons surviving as of June 30, 1988, was analyzed by age, sex, region of residence, relative amount of pension, and social security fund of membership prior to the consolidation of the system in 1967. The thirteen former funds were grouped into the five categories of government, commerce, industry, self-employed, and other, which were assumed to be proxies for the activity sector in which the individual spent his active life. The sample is not representative of the Argentine population, since it excludes the lowest and highest socioeconomic strata and overrepresents men and urban residents. It is, however, believed to be adequate for explaining mortality differentials for most of the population covered by the social security system. The study methodology was based on the technique of logistic analysis and on the use of regional model life tables developed by Coale and others. To evaluate the effect of the study variables on the probability of dying, a regression model of maximal verisimilitude was estimated. The model relates the logit of the probability of death between ages 65 and 95 to the available explanatory variables, including their possible interactions. Life tables were constructed by sex, region of residence, previous pension fund, and income. As a test of external consistency, a model including only age and sex as explanatory variables was constructed using the methodology. The results confirmed consistency between the estimated values and other published estimates. A significant conclusion of the study was that

  1. Temporal evolution of mineralization events in the Bohemian Massif inferred from the Re-Os geochronology of molybdenite

    Czech Academy of Sciences Publication Activity Database

    Ackerman, Lukáš; Haluzová, Eva; Creaser, R. A.; Pašava, J.; Veselovský, F.; Breiter, Karel; Erban, V.; Drábek, M.

    2017-01-01

    Roč. 52, č. 5 (2017), s. 651-662 ISSN 0026-4598 R&D Projects: GA ČR GA13-15390S Institutional support: RVO:67985831 Keywords : Re-Os * geochronology * molybdenite * Bohemian Massif * granite Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 3.396, year: 2016

  2. K-Ar geology, geochemistry and geochronology from the Maria River region dikes, Parana State southeastern part, Brazil

    International Nuclear Information System (INIS)

    Silva Junior, Renato Oliveira da; Dall'Agnol, Roberto; Oliveira, Elson Paiva de

    1996-01-01

    The paper synthesizes the geological, petrographical, geochemical and geochronological data from the Maria River region dikes, situated at the southeastern part of the Para State, Brazil. It identifies five groups of dikes and determines the age of these dikes, through the Potassium-Argon (K-Ar) methodology

  3. Geochronology Intermediary Laboratory implantation at the Rio Grande do Norte Federal University: the dating of the Serrinha Granitoid (RN) and the correlate Brasiliana extensional deformation

    International Nuclear Information System (INIS)

    Macedo, Maria Helena F.; Sa, Emanuel F. Jardim de; Souza, Zorano S.; Mendes, Franklin S.; Ramalho, Karlos A.C.

    1997-01-01

    The article describes the activities developed by the Geochronology Intermediary Laboratory at the Federal University of the Rio Grande do Norte, a Brazilian university, where there were the preoccupation of establishing strategies for a geochronological development. It relates the Rubidium-Strontium (Rb/Sr) and Samarium-Neodymium (Sm/Nd) methods, describing the analysis realized in these methodologies. Afterward, it presents the geological and petrographic situation of the Granitoide de Serrinha, located at Rio Grande do Norte State, Brazil and its geochronological data

  4. 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

  5. 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

  6. Relationship between LIBS Ablation and Pit Volume for Geologic Samples: Applications for in situ Absolute Geochronology

    Science.gov (United States)

    Devismes, D.; Cohen, Barbara A.

    2014-01-01

    In planetary sciences, in situ absolute geochronology is a scientific and engineering challenge. Currently, the age of the Martian surface can only be determined by crater density counting. However this method has significant uncertainties and needs to be calibrated with absolute ages. We are developing an instrument to acquire in situ absolute geochronology based on the K-Ar method. The protocol is based on the laser ablation of a rock by hundreds of laser pulses. Laser Induced Breakdown Spectroscopy (LIBS) gives the potassium content of the ablated material and a mass spectrometer (quadrupole or ion trap) measures the quantity of 40Ar released. In order to accurately measure the quantity of released 40Ar in cases where Ar is an atmospheric constituent (e.g., Mars), the sample is first put into a chamber under high vacuum. The 40Arquantity, the concentration of K and the estimation of the ablated mass are the parameters needed to give the age of the rocks. The main uncertainties with this method are directly linked to the measures of the mass (typically some µg) and of the concentration of K by LIBS (up to 10%). Because the ablated mass is small compared to the mass of the sample, and because material is redeposited onto the sample after ablation, it is not possible to directly measure the ablated mass. Our current protocol measures the ablated volume and estimates the sample density to calculate ablated mass. The precision and accuracy of this method may be improved by using knowledge of the sample's geologic properties to predict its response to laser ablation, i.e., understanding whether natural samples have a predictable relationship between laser energy deposited and resultant ablation volume. In contrast to most previous studies of laser ablation, theoretical equations are not highly applicable. The reasons are numerous, but the most important are: a) geologic rocks are complex, polymineralic materials; b) the conditions of ablation are unusual (for example

  7. Mixed Messages from Garnet Lu-Hf and Sm-Nd Geochronology

    Science.gov (United States)

    Vervoort, J. D.; Wang, D.; Johnson, T. A.

    2017-12-01

    Garnet geochronology provides important information on the timing and conditions of metamorphism. As a major indicator mineral formed during metamorphism, its direct dating can not only help establish the timing of metamorphism, provide the "t" for P-T-t paths, but also, if the dated garnet can be placed in a textural context, can provide information on the timing of deformational features. With advances in chemistry and mass spectrometry, garnet Lu-Hf and Sm-Nd geochronology has become an important geochronological tool and we can now reliably (if not routinely) date a wide variety of garnet compositions formed under diverse conditions. In the course of dating a variety of lithologies using both Lu-Hf and Sm-Nd isotope systems, however, some intriguing results have emerged. Although there are many examples where the Lu-Hf and Sm-Nd systems give the same date within uncertainty, there are also many cases where these systems yield significantly different dates, and the differences between these dates can be considerable—many 10's of Ma of and even 100's of Ma. For example, in garnet-bearing Mesoproterozoic gneisses from across the Blue Ridge Province in Virginia, both Lu-Hf and Sm-Nd analyses (determined on the same solutions) define narrow time spans, but with the Sm-Nd dates systematically younger (for orthogneisses Lu-Hf dates are 1032 to 1019 Ma whereas Sm-Nd dates are 965 to 949 Ma—a difference of 67 to 80 Ma). There are many other examples of systematically younger Sm-Nd garnet dates in both the literature and with our ongoing research. Potential explanations for these differences include: 1) strong partitioning of Lu into garnet during growth yielding ages weighted toward the beginning of growth; 2) faster Lu diffusion from high Lu regions after garnet formation, potentially leading to isochron rotation and anomalously old Lu-Hf dates; and 3) differences in closure temperatures of the two isotope systems. We will review several examples of divergent Lu

  8. Biodiversity information system of the national parks administration of Argentina

    Directory of Open Access Journals (Sweden)

    Leonidas Lizarraga

    2014-06-01

    Full Text Available Introduction The Biodiversity Information System (BIS of the National Parks Administration of Argentina (NPA was launched in 2002, with the support of the Global Environmental Fund (GEF through the Biodiversity Conservation Project in Argentina. The BIS consists of a set of thematic databases and Geographic Information System (GIS set to support management decisions, and to provide information to the general public on the national protected areas of Argentina. Currently, the BIS-NPA progr...

  9. 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

  10. 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

  11. 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

  12. Argentina : tous les projets | Page 4 | CRDI - Centre de recherches ...

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

    Région: Argentina, South America, Brazil, Chile, Mexico, North and Central America ... Sujet: WOMEN'S PARTICIPATION, POLITICS, POLITICAL LEADERSHIP, WOMEN'S RIGHTS, GENDER ... Sujet: BIOLOGY, BIODIVERSITY, ECOLOGY.

  13. Argentina : tous les projets | Page 7 | CRDI - Centre de recherches ...

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

    Sujet: INTERNATIONAL AGREEMENTS, WOMEN'S RIGHTS, LEGISLATION, ACCESS TO ... SERVICES, GENDER DISCRIMINATION, GENDER EQUALITY, Gender ... Région: Argentina, Bangladesh, Brazil, India, Lebanon, Malawi, Viet Nam.

  14. Argentina : tous les projets | Page 8 | CRDI - Centre de recherches ...

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

    ... INNOVATIONS, INFORMATION TECHNOLOGY, Internet, TEACHING AIDS, ... Région: Argentina, South America, Brazil, Chile, Colombia, Mexico, North and ... Sujet: SOCIAL PARTICIPATION, Civil society, HEALTH SYSTEM, Evaluation.

  15. LAS ESPECIES ARGENTINAS DEL GENERO SICYOS (CUCURBITACEAE.

    Directory of Open Access Journals (Sweden)

    Raúl Martínez Crovetto

    1964-01-01

    Full Text Available El autor estudia las especies del género Sicyos que viven dentro del territorio de la República Argentina; señalando que hasta el presente se han hallado seis. Luego de una diagnosis del género, suministra una clave, descripciones y figuras de cada una de ellas, a fin de facilitar su reconocimiento. Las especies estudiadas son S. malvifolius Griseb., S. polyacanthus Cogn., S. Odanellii Mart.-Crov., S. Kunthii Cogn. (nuevo habitante para la flora argentina, S. Warmingii Cogn, S. Warmingii Cogn. var. longispina Mart.-Crov. (nueva variedad y S. ignarus Mart.-Crov. (especie nueva para la ciencia.

  16. La migracion internacional en Argentina hacia 2010

    Directory of Open Access Journals (Sweden)

    Laura Calvelo

    Full Text Available El artículo presenta los principales lineamientos de la migración internacional en Argentina hacia el año 2010, con detenimiento en el período 2000-2010. En el caso de la inmigración no nativa se basa en información de los censos nacionales de población 2001 y 2010. En el caso de la migración internacional de la población nativa de Argentina el análisis se sustenta en información de censos extranjeros hasta la ronda 2000 y en otras fuentes de datos de los principales países de destino hasta 2010 (Estados Unidos y España.

  17. Measurements of atmospheric fallout in Argentina

    International Nuclear Information System (INIS)

    Canoba, A.C.; Lopez, F.O.; Bruno, H.A.

    1998-01-01

    With the purpose of studying the radioactive fallout present in Argentina from atmospheric nuclear explosions tests that have been conducted recently, an environmental monitoring program, outside the influence of nuclear facilities of Argentina, was undertaken during 1996 and 1997. The levels of Cs-137 and Sr-90 were analysed in samples of air, deposited material (rainwater), milk, an average meal of a standard man and food. During this period, a total of 630 radiochemical analysis were performed on 325 samples of the different matrices described. The concentration levels of the radionuclides analysed in the different environmental matrices are presented and are compared with the values obtained in the environmental monitoring program done during the period 1960-1981. (author) [es

  18. Spent fuel management of NPPs in Argentina

    International Nuclear Information System (INIS)

    Alvarez, D.E.; Lee Gonzalez, H.M.

    2010-01-01

    There are two Nuclear Power Plants in operation in Argentina: 'Atucha I' (unique PHWR design) in operation since 1974, and 'Embalse' (typical Candu reactor) which started operation in 1984. Both NPPs are operated by 'Nucleoelectrica Argentina S.A' which is responsible for the management and interim storage of spent fuel till the end of the operative life of the plants. A third NPP, 'Atucha II' is under construction, with a similar design of Atucha I. The legislative framework establishes that after final shutdown of a NPP the spent fuel will be transferred to the 'National Atomic Energy Commission', which is also responsible for the decommissioning of the Plants. In Atucha I, the spent fuel is stored underwater, until another option is implemented meanwhile in Embalse the spent fuel is stored during six years in pools and then it is moved to a dry storage. A decision about the fuel cycle back-end strategy will be taken before year 2030. (authors)

  19. Cultural Diversity: "Reports from Brazil and Argentina"

    Directory of Open Access Journals (Sweden)

    Célia Regina Rossi

    2007-06-01

    Full Text Available This article tells two experiences of projects carried through in schools of basic education whose thematic it was the work with the cultural diversity, the valuation of other cultures and reflections on the proper culture The work was carried through in two schools: one in the state of São Paulo, the city of Rio Claro where as the thematic one worked was the Hip-Hop and cultural manifestations local Brazilians the second in the capital of a Argentina province, in the city of Paraná where it worked the contact and the relation enter the cultural manifestations of Brazil and Argentina The central objective of this work was to think ways that could lead to the construction of a school that it considered the differences and the learning that happens when these (the differences they are in relation.

  20. Argentina and Brazil: an evolving nuclear relationship

    International Nuclear Information System (INIS)

    Redick, J.R.

    1990-01-01

    Argentina and Brazil have Latin America's most advanced nuclear research and power programs. Both nations reject the Non-Proliferation Treaty (NPT), and have not formally embraced the Tlatelolco Treaty creating a regional nuclear-weapon-free zone. Disturbing ambiguities persist regarding certain indigenous nuclear facilities and growing nuclear submarine and missile capabilities. For these, and other reasons, the two nations are widely considered potential nuclear weapon states. However both nations have been active supporters of the International Atomic Energy Agency (IAEA) and have, in recent years, assumed a generally responsible position in regard to their own nuclear export activities (requiring IAEA safeguards). Most important, however, has been the advent of bilateral nuclear cooperation. This paper considers the evolving nuclear relationship in the context of recent and dramatic political change in Argentina and Brazil. It discusses current political and nuclear developments and the prospects for maintaining and expanding present bilateral cooperation into an effective non-proliferation arrangement. (author)

  1. Rocky Mountain spotted fever in Argentina.

    Science.gov (United States)

    Paddock, Christopher D; Fernandez, Susana; Echenique, Gustavo A; Sumner, John W; Reeves, Will K; Zaki, Sherif R; Remondegui, Carlos E

    2008-04-01

    We describe the first molecular confirmation of Rickettsia rickettsii, the cause of Rocky Mountain spotted fever (RMSF), from a tick vector, Amblyomma cajennense, and from a cluster of fatal spotted fever cases in Argentina. Questing A. cajennense ticks were collected at or near sites of presumed or confirmed cases of spotted fever rickettsiosis in Jujuy Province and evaluated by polymerase chain reaction assays for spotted fever group rickettsiae. DNA of R. rickettsii was amplified from a pool of A. cajennense ticks and from tissues of one of four patients who died during 2003-2004 after illnesses characterized by high fever, severe headache, myalgias, and petechial rash. The diagnosis of spotted fever rickettsiosis was confirmed in the other patients by indirect immunofluorescence antibody and immunohistochemical staining techniques. These findings show the existence of RMSF in Argentina and emphasize the need for clinicians throughout the Americas to consider RMSF in patients with febrile rash illnesses.

  2. Investment in Renewable Energies in Argentina

    OpenAIRE

    Marina Recalde

    2017-01-01

    This article analyzes how the enabling conditions of the energy policy of a developing country such as Argentina, are crucial for the deployment of renewable energy investments. The conclusions highlights that the low institutional quality of the country shapes enabling conditions and reduce effect of the instruments of the energy policy, dropping incentives for investment in renewable technologies in the country. Therefore, in order to promote renewable technologies investments efficiently, ...

  3. Investment in Renewable Energies in Argentina

    Directory of Open Access Journals (Sweden)

    Marina Recalde

    2017-05-01

    Full Text Available This article analyzes how the enabling conditions of the energy policy of a developing country such as Argentina, are crucial for the deployment of renewable energy investments. The conclusions highlights that the low institutional quality of the country shapes enabling conditions and reduce effect of the instruments of the energy policy, dropping incentives for investment in renewable technologies in the country. Therefore, in order to promote renewable technologies investments efficiently, the institutional framework of countries must be seriously improved.

  4. Area Handbook Series: Argentina: A Country Study

    Science.gov (United States)

    1985-08-01

    votes after a campaign that emphasized firm opposition to the military government and verbal attacks on the trade union leadership of the PJ...legal pro- cedures that were designed especially for these cases. The trials were open to the public, evidence would be taken verbal - ly instead of...1981,144-45. Terrera, Guillermo Alfredo. Geopolitica Argentina: Poblacion, fronteras, comunicaciones , antropologia. Buenos Aires: Edi- torial Plus

  5. Memories of the armed struggle in Argentina

    Directory of Open Access Journals (Sweden)

    Laura Margarita Pasquali

    2013-06-01

    Full Text Available This article presents and develops some of the edges on working of the guerrilla that emerge in the memories of the former militants of the armed organizations in Argentina. Beginig from this journey we will have access to the registration that one has presently on it, which will allows us to establish part of the subjective environment of the moment, the main characters consideration of the activism and their significance in the general context of the militancy.

  6. Burden of Serious Fungal Infections in Argentina

    Directory of Open Access Journals (Sweden)

    Fernando O. Riera

    2018-04-01

    Full Text Available The number of fungal infections at any given time in Argentina is not known. Here we estimate the burden of serious fungal infections in Argentina for the first time. Specific population statistics were searched from multiple sources, local literature was identified, and estimates made. Some additional data were sourced from the Ministry of Health, the Global Initiative for Asthma (GINA program, and national haematology and transplant societies. Argentina has a population of 43.8 million, with 25% of this total being children under 15 years. The predicted candidemia annual incidence is 2193 cases, with 50% occurring in the ICU. At a 6% prevalence rate, an estimated 593,695 women suffer from recurrent vulvovaginal candidiasis. Invasive aspergillosis is relatively common because of high smoking and chronic obstructive pulmonary disease (COPD rates, with 268 cases in immunocompromised patients and another 1938 in the 168,000 COPD patients admitted to hospital. Asthma is also common, affecting 14% of adults, and so allergic bronchopulmonary aspergillosis (ABPA and severe asthma with fungal sensitization (SAFS are major problems. An estimated 432 cases of cryptococcal meningitis (CM—90% of them in AIDS patients—and 1177 cases of Pneumocystis pneumonia (PCP occur each year. The estimated annual case number of disseminated histoplasmosis is 404 in AIDS patients, almost as frequent as CM. Paracoccidioidomycosis annual incidence is estimated at 219, and coccidioidomycosis at 16 cases. At least 881,023 people (>2.01% in Argentina are affected by a serious fungal disease annually, with considerable morbidity and mortality.

  7. The "Private School Advantage" in Argentina

    Directory of Open Access Journals (Sweden)

    Gustavo E. Fischman

    2001-08-01

    Full Text Available Local actors' perceptions of curricular and management changes in two private schools and one neighboring public secondary school in the city of Buenos Aires, Argentina, are analyzed. An exploration was conducted of how, within an ideologically and politically pro-reform context and a widespread acceptance of the "private school advantage," principals, teachers, and students in these schools evaluated the changes (or lack of them in management, teaching, and curriculum orientations of the secondary education sector.

  8. Where is Argentina going in geothermal energy

    Energy Technology Data Exchange (ETDEWEB)

    Mange, J

    1977-01-01

    A brief review is given of geothermal exploration and development in Argentina. Methodical efforts to inventory the geothermal resources of the country were begun in 1974. The Commission set itself the task of locating the geothermal anomalies and then selecting particular anomalies for intensive exploration in order to confirm or discard the possibilities of exploiting the resource. The known principal anomalies are listed and the two selected for intensive exploration are indicated. (JSR)

  9. The Andean Swallow (Orochelidon andecola) in Argentina

    OpenAIRE

    Mazar Barnett, Juan; Pugnali, Germán D.; Pearman Morrison, Mark; Bodrati, Alejandro; Moschione, Flavio; Clark, Ricardo; Roesler, Carlos Ignacio; Monteleone, Diego; Casañas, Hernán; Burgos Gallardo, Freddy; Segovia, José; Pagano, Luis; Povedano, Hernán; Areta, Juan Ignacio

    2016-01-01

    During ornithological studies in the provinces of Jujuy, Salta, and San Juan, we recorded the Andean Swallow Orochelidon andecola at 40 localities. These are the first records in Argentina, and also represent the southernmost for the species. Some of these localities are up to 1500 m lower than the previously known elevational limit (now 800 masl), and up to 1100 km southwards. This is a relatively poorly known swallow, and we present novel natural history data. We found evidence of breeding ...

  10. The "Private School Advantage" in Argentina

    OpenAIRE

    Gustavo E. Fischman

    2001-01-01

    Local actors' perceptions of curricular and management changes in two private schools and one neighboring public secondary school in the city of Buenos Aires, Argentina, are analyzed. An exploration was conducted of how, within an ideologically and politically pro-reform context and a widespread acceptance of the "private school advantage," principals, teachers, and students in these schools evaluated the changes (or lack of them) in management, teaching, and curriculum orientations of the se...

  11. About the Triple A. Argentina 1973 - 1976

    OpenAIRE

    Rostica, Julieta

    2011-01-01

    On May 25, 1973, Peronism returned to govern Argentina after about two decades of prohibition and political persecution. After its establishment, certain crimes began to be signed with “AAA”. The Triple A adopted the particularity of disappearing with the coup on March 24 1976. Why could this organization only exist in a democracy erected in the middle of two military dictatorships? Why did it exist during the very wished Peronist government? The article offers an approach to the Triple A, th...

  12. Effects of irradiation on minerals and their consequences in geo-chronology

    International Nuclear Information System (INIS)

    Seydoux-Guillaume, Anne-Magali

    2011-01-01

    In this HDR (accreditation to supervise research studies) report, the author first gives a brief overview of her scientific approach. Then, addressing the irradiation of minerals by a radioactive source, she discusses the effects of irradiation, notably in the case of monazite, reports an experimental approach of external irradiation by ion beams, and comments some side effects like irradiation of host minerals. She also comments how irradiation-induced damages interfere with some processes like diffusion kinetics and dissolution. She addresses the case of mineral irradiation by means of a femto-second laser source: scientific approach, effects on mineral microstructure, notably in the case of monazite and quartz. The last part discusses issues in abeyance and perspectives in the field of irradiation textures, consequences on the geo-chronological response, alteration mechanisms, role of defects, and contribution of experimental irradiation

  13. The Lathrop Wells volcanic center: Status of field and geochronology studies

    International Nuclear Information System (INIS)

    Crowe, B.; Morley, R.; Wells, S.; Geissman, J.; McDonald, E.; McFadden, L.; Perry, F.; Murrell, M.; Poths, J.; Forman, S.

    1993-01-01

    The Lathrop Wells volcanic center is located 20 km south of the potential Yucca Mountain site, at the south end of the Yucca Mountain range. It has long been recognized as the youngest basalt center in the region. However, determination of the age and eruptive history of the center has proven problematic. The purpose of this paper is to describe the status of field and geochronology studies of the Lathrop Wells center. Our perspective is that it is critical to assess all possible methods for obtaining cross-checking data to resolve chronology and field problems. It is equally important to consider application of the range of chronology methods available in Quaternary geologic research. Such an approach seeks to increase the confidence in data interpretations through obtaining convergence among separate isotopic, radiogenic, and age-correlated methods. Finally, the assumptions, strengths, and weaknesses of each dating method need to be carefully described to facilitate an impartial evaluation of results

  14. PALEOARCHEAN MAFIC ROCKS OF THE SOUTHWESTERN SIBERIAN CRATON: PRELIMINARY GEOCHRONOLOGY AND GEOCHEMICAL CHARACTERIZATION

    Directory of Open Access Journals (Sweden)

    A. V. Ivanov

    2017-01-01

    Full Text Available The Siberian craton consists of Archean blocks, which were welded up into the same large unit by ca 1.9 Ga [Gladkochub et al., 2006; Rojas-Agramonte et al., 2011]. The history of the constituent Archean blocks is mosaic because of limited number of outcrops, insufficient sampling coverage because of their location in remote regions and deep forest and difficulties with analytical studies of ancient rocks, which commonly underwent metamorphic modifications and secondary alterations. In this short note, we report data on discovery of unusual for Archean mafic rocks of ultimate fresh appearance. These rocks were discovered within southwestern Siberian craton in a region near a boundary between Kitoy granulites of the Sharyzhalgai highgrade metamorphic complex and Onot green-schist belt (Fig. 1. Here we present preliminary data on geochronology of these rocks and provide their geochemical characterization.

  15. Understanding sudden environmental and societal change through coupled geochronological and artefact shape analyses

    DEFF Research Database (Denmark)

    Hoggard, Christian Steven; Sauer, Florian Rudolf; Zernack, Anke Verena

    Over the last twenty years, advances in geometric morphometric methodologies have revolutionised how archaeologists understand changes in artefact shape and form (size plus shape) throughout the Quaternary period. Such methodologies provide a high resolution of artefact coverage, and allow...... a critical analysis of previous taxonomic classificatory schemas and human tool-use in the past. Despite this, methodologies into artefact shape through geometric morphometrics have not been integrated within extensive geochronological data to better understand periods of high environmental stress and......, with respect to archaeology, how past societies reacted to such stress. The Laacher See volcanic eruption (c. 13,000 BP) in western Germany is believed, given its hypothesised characteristics, to have had profound impact on the lifeways of hunter-gatherers towards the end of the Final Palaeolithic (Riede, 2017...

  16. Temporal dynamics of airborne lead-210 in Missouri (USA): implications for geochronological methods

    International Nuclear Information System (INIS)

    Sheets, R.W.; Lawrence, A.E.

    1999-01-01

    Lead-210 ( 210 Pb) deposited from the atmosphere is used in the dating of certain geological materials such as glacial ice and lacustrine sediments, but its long-term atmospheric behavior has been little studied. The present investigation reports measurements of airborne 210 Pb at 21 monitoring stations in Springfield, Missouri, during 1975-1995. Seasonal and diurnal patterns of atmospheric concentrations are established, and the mean annual concentrations of 210 Pb in ground level air during the 20-year period are examined. Although airborne 210 Pb concentrations are found to vary diurnally and seasonally, mean annual concentrations in southwest Missouri have remained relatively constant during this time period. This finding is important for geochronological methods that assume a constant 210 Pb flux from the atmosphere. (orig.)

  17. In Situ Potassium-Argon Geochronology Using Fluxed Fusion and a Double Spike

    Science.gov (United States)

    Hurowitz, Joel A.; Hecht, Michael H.; Zimmerman, Wayne F.; Neidholdt, Evan L.; Sinha, Mahadeva P.; Sturhahn, Wolfgang; Coleman, Max; McCleese, Daniel J.; Farley, Kenneth A.; Eiler, John M.; hide

    2012-01-01

    A document highlights an Li-based fluxing agent that enables sample fusion and quantitative Ar-release at relatively low temperatures (900-1,000 C), readily achievable with current flight resistance furnace designs. A solid, double spike containing known quantities of Ar-39 and K-41 was developed that, when added in known amounts to a sample, enables the extraction of a Ar-40/K-40 ratio for age estimation without a sample mass measurement. The use of a combination of a flux and a double spike as a means of solving the mechanical hurdles to an in situ K-Ar geochronology measurement has never been proposed before. This methodology and instrument design would provide a capability for assessing the ages of rocks and minerals on the surfaces of planets and other rocky terrestrial bodies in the solar system.

  18. Acute intermittent porphyria in Argentina: an update.

    Science.gov (United States)

    Cerbino, Gabriela Nora; Gerez, Esther Noemí; Varela, Laura Sabina; Melito, Viviana Alicia; Parera, Victoria Estela; Batlle, Alcira; Rossetti, María Victoria

    2015-01-01

    Porphyrias are a group of metabolic diseases that arise from deficiencies in the heme biosynthetic pathway. A partial deficiency in hydroxymethylbilane synthase (HMBS) produces a hepatic disorder named Acute Intermittent Porphyria (AIP); the acute porphyria is more frequent in Argentina. In this paper we review the results obtained for 101 Argentinean AIP families and 6 AIP families from foreign neighbour countries studied at molecular level at Centro de Investigaciones sobre Porfirinas y Porfirias (CIPYP). Thirty-five different mutations were found, of which 14 were described for the first time in our population. The most prevalent type of mutations was the missense mutations (43%) followed by splice defects (26%) and small deletions (20%). An odd case of a double heterozygous presentation of AIP in a foreign family from Paraguay is discussed. Moreover, it can be noted that 38 new families were found carrying the most frequent mutation in Argentina (p.G111R), increasing to 55.66% the prevalence of this genetic change in our population and adding further support to our previous hypothesis of a founder effect for this mutation in Argentina. Identification of patients with an overt AIP is important because treatment depends on an accurate diagnosis, but more critical is the identification of asymptomatic relatives to avoid acute attacks which may progress to death.

  19. La letteratura italiana tradotta in Argentina

    Directory of Open Access Journals (Sweden)

    Silvia Cattoni

    2017-11-01

    Full Text Available In due secoli di storia della letteratura argentina, lo sviluppo della letteratura italiana tradotta è in stretto rapporto con i propositi pedagogici o estetici determinati dal contesto culturale dei diversi momenti storici. In linea di massima, è possibile affermare che, dalla conformazione dello Stato nazionale e durante i primi decenni del XX secolo, la traduzione letteraria mirava ad ampliare l’orizzonte culturale di un lettore che si consolidava al ritmo della fiammante nazione. Nelle fasi successive e in stretto rapporto con la politica culturale portata avanti da Victoria Ocampo a partire dal 1931 tramite la rivista Sur e il suo posteriore progetto editoriale, la traduzione è stata soprattutto una pratica di scrittura che ebbe un’influenza decisiva nell’ordito della letteratura nazionale favorendo il suo rinnovo e incentivando le versioni di traduttori argentini. Fu questa un’apertura che favorì, durante la seconda metà del secolo, nel contesto della ricezione della letteratura universale, l’ingresso della letteratura italiana in Argentina. Il presente lavoro tratta in maniera sistematica, ma provvisoria, il panorama della letteratura italiana tradotta in Argentina. Lo scopo principale comporta il registro dei momenti più fecondi e l’interpretazione degli esiti ottenuti nei confronti della traduzione nel sistema letterario nazionale.

  20. (U-Th)/He geochronology of goethite and the origin and evolution of cangas

    Science.gov (United States)

    Monteiro, Hevelyn S.; Vasconcelos, Paulo M.; Farley, Kenneth A.; Spier, Carlos A.; Mello, Claudio L.

    2014-04-01

    (U-Th)/He geochronology of 147 grains of goethite cements extracted from ferruginous duricrusts (cangas) developed on banded iron-formations from the Quadrilátero Ferrífero region, Minas Gerais, Brazil, records a history of protracted mineral dissolution-reprecipitation that started at ca. 48.1 ± 4.8 Ma and continues intermittently until the Present. A large majority of the samples (more than 30%) are younger than 2 Ma, revealing active mineral dissolution-reprecipitation in the recent past. Within cangas, goethite cements are younger near the surface and become progressively older towards the bottom of the weathering profile, indicating that iron is more effectively cycled in the parts of the weathering profile more strongly affected by biogenic activity. (U-Th)/He geochronology of 14 goethite grains from saprolites in the same profiles yield results ranging from 55.3 ± 5.5 to 25.7 ± 2.6 Ma. For a single weathering profile, goethite cements from cangas are invariably younger than goethite grains from the underlying saprolite, indicating that the duricrust and the saprolite behave as independent and separate systems responding to different environmental controls. Thorium shows conservative behaviour during goethite dissolution-reprecipitation, and it is enriched towards the surface of the weathering profile. Uranium, on the other hand, is preferentially leached from the surface into the saprolite or out of the weathering profile. Recurrent goethite dissolution-reprecipitation lends great textural complexities to cangas, but it is also responsible for its capacity to reheal when physically disrupted. This self-healing property accounts for canga’s role in armoring banded iron-formation landscapes.

  1. Quantitative laser-induced breakdown spectroscopy of potassium for in-situ geochronology on Mars

    Energy Technology Data Exchange (ETDEWEB)

    Stipe, Christopher B., E-mail: stipec@seattleu.edu [Department of Mechanical Engineering, Seattle University, Seattle, WA 98122 (United States); Guevara, Edward; Brown, Jonathan [Department of Mechanical Engineering, Seattle University, Seattle, WA 98122 (United States); Rossman, George R. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States)

    2012-04-15

    Laser-induced breakdown spectroscopy is explored for the development of an in-situ K-Ar geochronology instrument for Mars. Potassium concentrations in standard basaltic glasses and equivalent rock samples in their natural form are quantified using the potassium doublet at 766.49 and 769.90 nm. Measurement precision varies from 0.5 to 5.5 (% RSD) over the 3.63% to 0.025% potassium by weight for the standard samples, and little additional precision is achieved above 20 laser shots at 5 locations. For the glass standards, the quantification limits are 920 and 66 ppm for non-weighted and weighted calibration methods, respectively. For the basaltic rocks, the quantification limits are 2650 and 328 ppm for the non-weighted and weighted calibration methods, respectively. The heterogeneity of the rock samples leads to larger variations in potassium signal; however, normalizing the potassium peak by base area at 25 locations on the rock improved calibration accuracy. Including only errors in LIBS measurements, estimated age errors for the glasses range from approximately {+-} 30 Ma for 3000 Ma samples to {+-} 2 Ma for 100 Ma samples. For the basaltic rocks, the age errors are approximately {+-} 120 Ma for 3000 Ma samples and {+-} 8 Ma for 100 Ma samples. - Highlights: Black-Right-Pointing-Pointer Measurement of basaltic glasses and rocks by laser-induced breakdown spectroscopy. Black-Right-Pointing-Pointer Quantification of potassium for K-Ar dating. Black-Right-Pointing-Pointer Development of an instrument for in-situ geochronology on Mars. Black-Right-Pointing-Pointer Detection limit is 35 ppm, relative standard deviations range from 0.5% to 5.5%. Black-Right-Pointing-Pointer Estimated errors for the glass standards range from {+-} 30 Ma for 3000 Ma and {+-} 2 Ma for 100 Ma; estimated errors for the basaltic rocks range from {+-} 120 Ma for 3000 Ma and {+-} 8 Ma for 100 Ma.

  2. 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.

  3. 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)

  4. 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.

  5. 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.

  6. 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)

  7. 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.

  8. 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.

  9. The laser microprobe dating drives K-Ar geochronology into a new milestone at the end of 20th century

    International Nuclear Information System (INIS)

    Mu Zhiguo; Gao Yongjun

    2001-01-01

    K-Ar age dating method is facing a serious challenge to its application due to that both Ar loss and Ar excess are widespread found even though it has been undergoing 50 years. In the latest few years of the 20th century, studies on K-Ar geochronology have been pushing on a new step as a sign of method perfected and precision enhanced. High precision and high resolution 40 Ar/ 39 Ar dating, can use in both micro-area and a single grain, extends dating limit into the historical realm. Applied range of K-Ar geochronology is getting bigger and bigger due to fine analytical techniques while solved geological problems are getting wider and wider

  10. Floods, Droughts and Farming on the Plains of Argentina and ...

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

    2015-04-01

    Floods, Droughts and Farming on the Plains of Argentina and Paraguay, Pampas and Chaco Regions ... End Date. April 1, 2015 ... Argentina, South America, Paraguay, North and Central America ... IDRC is now accepting applications for this year's IDRC Doctoral Research Awards (IDRA). ... Careers · Contact Us · Site map.

  11. Argentina v globalizačních procesech

    OpenAIRE

    Chervets, Tamara

    2009-01-01

    The process of globalization is a very important issue these days. This work will describe the process of globalization in Argentina, especially its economic aspect (foreign direct investments, export and import of goods and services, migration of labor force). I will also mention the history of its development and Argentina's membership in most important international and regional organizations.

  12. Computing and Education in Argentina, Uruguay and Paraguay.

    Science.gov (United States)

    Sadowsky, Manuel

    Although the report is specifically about Argentina, Uruguay and Paraguay, the considerations presented are valid for all of Latin America. In September, 1969, Argentina had approximately 200 electronic computers. The annual growth is estimated at 15-20% and the implementation of teleprocessing and time-sharing systems have made evident the…

  13. All projects related to Argentina | Page 7 | IDRC - International ...

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

    Region: Americas, Argentina, South America. Program: Climate Change. Total Funding: CA$ 995,000.00. Youth Smoking in Stressed Environments : Determinants and Resiliency (Argentina, Colombia, Palestine). Project. Numerous studies have shown that the earlier an individual starts smoking, the harder it is to give it up.

  14. Unemployment Assistance and Transition to Employment in Argentina

    NARCIS (Netherlands)

    A. Iturriza (Ana); A.S. Bedi (Arjun Singh); R.A. Sparrow (Robert)

    2007-01-01

    textabstractIn 2001-02, Argentina experienced a wrenching economic crisis. Plan Jefes, implemented in May 2002, was Argentina's institutional response to the increases in unemployment and poverty triggered by the crisis. The program provided a social safety net and appears to have successfully

  15. Argentina: Social Sectors in Crisis. A World Bank Country Study.

    Science.gov (United States)

    World Bank, Washington, DC.

    Based on the findings of a two month visit to Argentina by a World Bank Mission in November/December of 1988, this report summarizes current economic, education, and social policies in Argentina. The four major areas targeted are the social sectors, education, health care, and housing. The analysis identifies critical problems in the organization…

  16. Prospect for Development of Open Access in Argentina

    Science.gov (United States)

    Miguel, Sandra; Bongiovani, Paola C.; Gomez, Nancy D.; Bueno-de-la-Fuente, Gema

    2013-01-01

    This perspective article presents an overview of the Open Access movement in Argentina, from a global and regional (Latin American) context. The article describes the evolution and current state of initiatives by examining two principal approaches to Open Access in Argentina: "golden" and "green roads". The article will then…

  17. Diccionario del español de Argentina

    OpenAIRE

    Haensch, Günther

    2000-01-01

    Diccionario del español de Argentina : español de Argentina - español de España / Günther Haensch ; Reinhold Werner. Madrid : Gredos, 2000. - LI, 729 S. - (Diccionarios contrastivos del español de América)

  18. Pro-Market Educational Governance: Is Argentina a Black Swan?

    Science.gov (United States)

    Beech, Jason; Barrenechea, Ignacio

    2011-01-01

    In this article we explore ways in which pro-market discourses have been interpreted in policy initiatives in Argentina since the 1970s. Our argument is that even though pro-market discourses have guided reforms in many aspects of public policies in Argentina, the arena of education has overall been resistant to taking them up. The first part of…

  19. 1 Estudio Sectorial Sector lácteo de Argentina

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

    Resumen: La producción de leche y productos lácteos conforma en Argentina un importante complejo productivo, de larga trayectoria histórica y gran impacto económico y social. En Argentina, esta industria conforma un oligopolio diferenciado en el que coexisten unas pocas grandes empresas nacionales y ...

  20. 78 FR 46610 - Lemon Juice From Argentina and Mexico

    Science.gov (United States)

    2013-08-01

    ... Argentina and Mexico Determination On the basis of the record \\1\\ developed in the subject five-year reviews... determines that termination of the suspended antidumping duty investigation on lemon juice from Mexico would...), entitled Lemon Juice from Argentina and Mexico: Investigation Nos. 731-TA-1105-1106 (Review). By order of...

  1. 78 FR 47006 - Lemon Juice From Argentina and Mexico

    Science.gov (United States)

    2013-08-02

    ... Argentina and Mexico Determination On the basis of the record \\1\\ developed in the subject five-year reviews... determines that termination of the suspended antidumping duty investigation on lemon juice from Mexico would...), entitled Lemon Juice from Argentina and Mexico: Investigation Nos. 731-TA-1105-1106 (Review). By order of...

  2. CALYPTRANTHES TRICONA (MYRTACEAE, NUEVA CITA PARA LA FLORA ARGENTINA

    Directory of Open Access Journals (Sweden)

    Sara G. Tressens

    1996-01-01

    Full Text Available Calyptranthes tricona D. Legrand (Myrtaceae es reportada por primera vez para la Argentina.  Se incluyen una descripción y una ilustración. Se presenta un clave para la identificación de las especies argentinas de Calyptranthes se da. Se discuten algunas observaciones sobre la nomenclatura C.concinna DC.

  3. Paleomagnetism and geochronological studies on a 450 km long 2216 Ma dyke from the Dharwar craton, southern India

    Science.gov (United States)

    Nagaraju, E.; Parashuramulu, V.; Kumar, Anil; Srinivas Sarma, D.

    2018-01-01

    Paleomagnetic and geochronological studies were carried out on a ∼ 450 km long (from 17 sites) N-S striking Paleoproterozoic dyke swarm exposed along a natural crustal cross section of about 10 km (increasing from North to South) in the Dharwar Craton, to study the characteristics of paleomagnetism and geochronology in vertical dimension. U-Pb/Pb-Pb dating on baddeleyite gives a crystallisation age of 2216.0 ± 0.9 Ma for long dyke AKLD. Paleomagnetic data from this well dated ∼ 2216 Ma dyke swarm in Dharwar Craton are of excellent quality. High coercivity and high blocking temperature components are carried by single domain magnetite and show dual polarity remanence directions. Combined normal and reverse polarity remanences on AKLD and other N-S dykes define the most reliable paleomagnetic pole for ∼ 2216 Ma at latitude 36°S and longitude 312°E (A95 = 7°). Though paleomagnetic data is unavailable on other N-S dykes below the Cuddapah basin, high precision geochronology suggest that they are of similar age within errors. Though there is a variation in the crustal depth of Dharwar craton from north to south, consistent Pb-Pb/U-Pb baddeleyite geochronology and paleomagnetic studies along the AKLD established its continuity and preservation along its entire strike length. The virtual geomagnetic poles of these sites confirm a stable remanence and are almost identical to the previously reported paleomagnetic pole and also supported by positive reversal test. Positive paleomagnetic reversal test on these dykes signify that the remanent magnetization is primary and formed during initial cooling of the intrusions. Updated apparent polar wander path of Dharwar craton indicates relatively low drift rate during 2.21-2.08 Ga interval. Magnetogranulometry and SEM studies show that remanent magnetization in this dyke was carried by single domain magnetite residing within silicate minerals.

  4. Geochronology and magnetic fabrics of the Altenberg-Teplice granite porphyry: implications for emplacement style of a caldera ring dike

    Czech Academy of Sciences Publication Activity Database

    Tomek, Filip; Žák, J.; Svojtka, Martin

    2016-01-01

    Roč. 46 (2016), s. 39-40 E-ISSN 1434-7512. [Late Paleozoic magmatism in the Erzgebirge / Krušné hory: Magma genesis, tectonics, geophysics, and mineral deposits : abstracts. 11.11.2016-12.11.2016, Freiberg] Institutional support: RVO:67985831 Keywords : porphyry * magnetic fabrics * geochronology * Altenberg-Teplice Subject RIV: DB - Geology ; Mineralogy http://tu-freiberg.de/sites/default/files/media/institut-fuer-geologie-718/pdf/fog_volume_46.pdf

  5. La familia Cyatheaceae (Pteridophyta en Argentina The family Cyatheaceae (Pteridophyta in Argentina

    Directory of Open Access Journals (Sweden)

    Gonzalo J Marquez

    2010-06-01

    Full Text Available La familia Cyatheaceae comprende alrededor de 500 especies de helechos arborescentes. Su distribución es pantropical y en Argentina se encuentra representada por 4 especies, reunidas en los géneros Alsophila y Cyathea: A. setosa, A. odonelliana, C. atrovirens y C. delgadii. En este trabajo se presenta una actualización de la información disponible hasta el momento referente a estas especies. Se exponen microfotografías de las esporas, que presentan la superficie con lomos en Alsophila y con cordones en Cyathea. Se ilustran los indusios y escamas de la base de los pecíolos, que son de importancia fundamental para la diferenciación de las especies estudiadas. Asimismo se presenta un mapa de distribución y una clave de las especies que crecen en Argentina.The family Cyatheaceae comprises about 500 species of tree ferns. Their distribution is pantropical and in Argentina is represented by four species, grouped in genera Alsophila y Cyathea: A. setosa, A. odonelliana, C. atrovirens and C. delgadii. In this paper, an update of the available information of the mentioned species is presented. A key to diferentiate the species growing in Argentina, their descriptions and a distribution map are also given. Spores are ridged in Alsophila and with rodlets in Cyathea. Indusia and scales of petiole basis are also illustrated.

  6. Petrology, chronology and sequence of vein systems: Systematic magmatic and hydrothermal history of a major intracontinental shear zone, Canadian Appalachians

    Science.gov (United States)

    Pe-Piper, Georgia; Piper, David J. W.; McFarlane, Chris R. M.; Sangster, Chris; Zhang, Yuanyuan; Boucher, Brandon

    2018-04-01

    Location of all illustrated samples. Table S3 Monazite geochronology lab data. Table S4 Allanite geochronology lab data. Fig. S1 Monazite geochronology analytical spots. Fig. S2 Allanite geochronology analytical spots.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. 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.

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

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    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

  16. 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

  17. 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

  18. Re-Os geochronology of a Mesoproterozoic sedimentary succession, Taoudeni basin, Mauritania: Implications for basin-wide correlations and Re-Os organic-rich sediments systematics

    Science.gov (United States)

    Rooney, Alan D.; Selby, David; Houzay, Jean-Pierre; Renne, Paul R.

    2010-01-01

    The exceptionally well-preserved sedimentary rocks of the Taoudeni basin, NW Africa represent one of the world's most widespread (> 1 M km 2) Proterozoic successions. Hitherto, the sedimentary rocks were considered to be Mid Tonian based on Rb-Sr illite and glauconite geochronology of the Atar Group. However, new Re-Os organic-rich sediment (ORS) geochronology from two drill cores indicates that the Proterozoic Atar Group is ˜ 200 Ma older (1107 ± 12 Ma, 1109 ± 22 Ma and 1105 ± 37 Ma). The Re-Os geochronology suggests that the Rb-Sr geochronology records the age of diagenetic events possibly associated with the Pan African collision. The new Re-Os geochronology data provide absolute age constraints for recent carbon isotope chemostratigraphy which suggests that the Atar Group is Mesoproterozoic and not Neoproterozoic. The new Re-Os ORS geochronology supports previous studies that suggest that rapid hydrocarbon generation (flash pyrolysis) from contact metamorphism of a dolerite sill does not significantly disturb the Re-Os ORS systematics. Modelled contact conditions suggest that the Re-Os ORS systematics remain undisturbed at ˜ 650 °C at the sill/shale contact and ≥ 280 °C 20 m from the sill/shale contact. Moreover, the Re-Os geochronology indicates that the West African craton has a depositional history that predates 1100 Ma and that ORS can be correlated on a basin-wide scale. In addition, the Re-Os depositional ages for the ORS of the Taoudeni basin are comparable to those of ORS from the São Francisco craton, suggesting that these cratons are correlatable. This postulate is further supported by identical Os i values for the Atar Group and the Vazante Group of the São Francisco craton.

  19. Tobacco industry targeting youth in Argentina

    Science.gov (United States)

    Braun, S; Mejia, R; Ling, P M; Pérez-Stable, E J

    2013-01-01

    Background/aim Argentina has one of the highest cigarette smoking rates among both men and women in the Americas and no legislated restrictions on tobacco industry advertising. The tobacco industry has traditionally expanded markets by targeting adolescents and young adults. The objective of this study was to determine whether and how the tobacco industry promotes cigarettes to adolescents in Argentina. Methods We conducted a systematic search of tobacco industry documents available through the internet dated between 1995 and 2004 using standard search terms to identify marketing strategies in Argentina. A selected review of the four leading newspapers and nine magazines with reported high readership among adolescents was completed. The selected print media were searched for tobacco images and these were classified as advertisements if associated with a commercial product or as a story if not. Results The tobacco industry used market segmentation as a strategy to target Argentinean consumers. British American Tobacco (BAT) undertook a young adult psychographic study and classified them as “progressives”, “Jurassics” or “conservatives” and “crudos” or “spoiled brats”. BAT marketed Lucky Strike to the “progressives” using Hollywood movies as a vehicle. The tobacco industry also targeted their national brands to the conservatives and linked these brands with “nationalistic values” in advertising campaigns. Philip Morris promoted Marlboro by sponsoring activities directed at young people and they launched the 10 cigarettes packet as a starter vehicle. Conclusions The tobacco industry used psychographic segmentation of the population and developed advertising strategies focused on youth. Tobacco control researchers and advocates must be able to address these strategies in counter-marketing interventions. PMID:18299308

  20. Neoliberalism and political actors in contemporary Argentina

    Directory of Open Access Journals (Sweden)

    Juan Manuel Reynares

    2017-11-01

    Full Text Available In this paper we set out a critical reading of the literature on political neoliberal actors in Argentina. We consider that the concentration of these studies in the national level has to do with a definition of neoliberalism as a set of economical and structural macro politics. We propose to define neoliberalism as a technology of government that intends to hegemonize an “enterprise form” in different social spheres, articulating a symbolical framework in a contingent and contentious way. This insight allows analyzing neoliberal identification processes as heterogeneous trajectories with diverse geographic and temporal scopes.

  1. JOURNALISM STUDIES IN ARGENTINA: BACKGROUND AND QUESTIONS

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    Adriana Amado

    2014-06-01

    Full Text Available This article summarizes the background of empirical journalism studies in Argentina.  In recent publications, researchers have consistently underscored the lack of data on the profession and the scarce development of theoretical frameworks related to journalism studies.  The local investigations have prioritized approaches and methods that do not give the whole picture of the population of journalists. Most of the research tends to equate media analysis and media messages with journalism study and keeps on failing to provide data that allows for learning about the working conditions and the professional profile of the Argentinean journalists.

  2. NUEVAS CITAS DE ASCLEPIADACEAE PARA ARGENTINA

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    Sergio A Cáceres Moral

    1989-01-01

    Full Text Available Dos especies no mencionadas anteriormente de la Argentina son tratadas e ilustradas: Oxypetalum molle Hook. et Arn. y Oxypetalum ineanum Fourn. Oxypetalum appendieulatum Mart. et Zucc., Oxypetalum confusum Malme, Oxypetalum jörgensenii Meyer, Oxypetalum microphyllum Hook. et Arn., Oxypetalum pannosum Decaisne, Oxypetalum stipatum Malme, Funastrum flavum (Decaisne Malme y Blepharodon lineare (Decaisne Decaisne se registran por primera vez para la flora de Corrientes ..

  3. 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)

  4. Characterization of agua de Ramon marbles, Cordoba Province, Argentina; Caracterizacion de los marmoles de agua de Ramon Provincia de Cordoba, Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Tourn, S; Castro, L. [Departamento de Ciencias Geologicas, Facultad de Ciencias Exactas y Naturales, Universidad de buenos Aires, (Argentina)]. E mail: selvia@fcen.uba.ar, lilianacastro@fibertel.com.ar

    2004-09-01

    Agua de Ramon district is located in the NW of Cordoba, Argentina, between 3 49' and 30{sup 0}52' S and 65{sup 0}21' and 65{sup 0}24' W, in the Eastern Pampean Range setting. It was a very important tungsten district until the end of 1950'decade when tungsten mining became of no economic interest. The objective is to report for the first time the petrological, mineralogical and geochemical characteristics of several marble lenses located in the sourthern of the area. Marble outcrops are lenticular ranging from 1 m to 80 m in length and 0.50 m to 20 m width. They appear massive, fine-grained and in light colors (white, pale green, very light brown and pale gray). These last varieties show a distinct banded structure due to little differences in color. These marbles are mainly composed of magnesian calcite accompanied by minor amounts of dolomite, forsterite, humite group minerals, tremolite, talc, serpentine and clinochlore, and scheelite, sphene, apatite and opaque minerals like hematite, magnetite, illmenite, pirrothite and pyrite as accessory minerals. Major chemical analyses indicate a relatively high SiO2 and MgO content, and minor CaO, in comparison with marbles of this type. Mineral paragenesis was useful to evaluate metamorphism conditions in this area. [Spanish] El distrito Agua de Ramon se localiza en el departamento de Minas al noroeste de la provincia de Cordoba, Argentina, entre los paralelos 30{sup 0}49' y 30{sup 0}52' de latitud sur y los meridianos 65{sup 0}21' y 65{sup 0}24' de longitud oeste, en el ambito de las Sierras Pampeanas Orientales. En el pasado constituyo un importante distrito de explotacion wolframifera, pero dicha actividad se halla paralizada desde fines de la decada del '50. El objetivo de este trabajo es hacer conocer por primera vez las caracteristicas de los marmoles localizados en el sector sur desde el punto de vista petrografico, mineralogico y geoquimico de manera que permita realizar un analisis petrogenetico. Los cuerpos son

  5. Yugoslav teachers in Argentina 1939-1944

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    Stefanović-Banović Milesa

    2014-01-01

    Full Text Available In this paper we present reports of Yugoslav teachers who held classes to immigrants in Argentina 1939-1944, organized by the government of Kingdom of Yugoslavia. Teachers’ reports to Yugoslav Embassy in Buenos Aires testify of Kingdom of Yugoslavia efforts to oppose assimilation and promote and strengthen “Yugoslav national unity”. The reports also describe general social circumstances of Yugoslav immigrants, show various details from their everyday life and contain valuable data on numerous political, economic, social and cultural problems of this diaspora in Argentina and their relationship with motherland. We believe that archive materials presented in this paper opens numerous questions which could be topics of separate researches. Some of them could be the following: To which extent the teachers’ reports represented the actual situation and to which they were shaped to match policy and expectations of Kingdom of Yugoslavia? What was the actual influence of teachers to spreading the “national unity” among immigrants? Have their work left trace in Yugoslav diaspora and in which way? Beside all of the open issues, it is certain that teachers’ reports contain valuable data on immigrants’ everyday life, curriculum, schooling conditions, relationship with motherland, etc. [Projekat Ministarstva nauke Republike Srbije, br. 47016: Interdisciplinarno istraživanje kulturnog i jezičkog nasleđa Srbije. Izrada multimedijalnog internet portala "Pojmovnik srpske kulture"

  6. Basic data for uranium prospecting in Argentina

    International Nuclear Information System (INIS)

    Belluco, A.; Rodriguez, E.; Martinez, C.; Marinkeff, K.

    1977-01-01

    After dealing briefly with the geochemical cycle of uranium in the earth's crust, and indicating the principal conditions under which different types of deposits are formed, the paper goes on to determine the uraniferous are of mainland Argentina (approximately 900000 km 2 ). Since evidence for the presence of uranium and other radioactive elements in many parts of the country has long been available, an attempt was made to systemize the existing information and classify the uraniferous sites so as to determine their temporal, spatial and genetic relationships with the different containing rocks. In addition, a study was made of the factors which contribute to the concentration of uranium in rocks which are accessible to prospecting (litho-stratigraphy, geological history, mettallogenic cycles, etc.). On the basis of these studies and considering the regional geology of Argentina, 21 ''regional environments'' were defined with varying degrees of probability of containing uranium; these environments will be submitted to long-term regional prospecting studies. It was necessary, however, to make a further sub-division into more homogeneous units with more clearly graded levels of priority, with the result that there are 65 ''prospecting units''. Each of these units, in order of priority, will be subjected to systematic prospecting. Exploratory work on a suitable scale will be carried out in the ''uraniferous'' districts of the ''prospecting units''. The main features of Argentine geology relating to the likelihood of uranium occurrences are briefly described, and maps of the large geotechtonic areas and the ''regional environments'' are included. (author)

  7. The industrial nuclear fuel cycle in Argentina

    International Nuclear Information System (INIS)

    Koll, J.H.; Kittl, J.E.; Parera, C.A.; Coppa, R.C.; Aguirre, E.J.

    1977-01-01

    The nuclear power program of Argentina for the period 1976-85 is described, as a basis to indicate fuel requirements and the consequent implementation of a national fuel cycle industry. Fuel cycle activities in Argentina were initiated as soon as 1951-2 in the prospection and mining activities through the country. Following this step, yellow-cake production was initiated in plants of limited capacity. National production of uranium concentrate has met requirements up to the present time, and will continue to do so until the Sierra Pintada Industrial Complex starts operation in 1979. Presently, there is a gap in local production of uranium dioxide and fuel elements for the Atucha power station, which are produced abroad using Argentine uranium concentrate. With its background, the argentine program for the installation of nuclear fuel cycle industries is described, and the techno-economical implications considered. Individual projects are reviewed, as well as the present and planned infrastructure needed to support the industrial effort [es

  8. Derechos humanos y sexualidad en la Argentina

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    Mario Pecheny

    2006-12-01

    Full Text Available Este artículo presenta un panorama de la situación de los derechos que tienen que ver con la sexualidad, en la Argentina contemporánea. Basándose principalmente en la legislación positiva, se presenta en primer lugar una síntesis del sistema legal y político, resumiendo a continuación el proceso de inclusión de los derechos sexuales, sobre todo desde 1983, cuando se recuperó la democracia. Las temáticas abordadas son: igualdad civil y conyugalidad, orientación sexual e identidad de género, reproducción, aborto, violencia de género y violencia sexual, VIH/sida, y explotación y trabajo sexual. El artículo concluye con una reflexión sobre las principales deudas pendientes.This paper presents an overview of the situation concerning the rights related to sexuality in contemporary Argentina. Based specially on the positive legislation, it is primarily presented a synthesis of the legal and political system. Next, the paper summarizes the process of inclusion of the sexual rights, mainly since 1983, when democracy has been recovered. The following issues are addressed: civil equality and conjugality; sexual orientation and gender identity; reproduction; abortion; gender a sexual violence; HIV/Aids; and exploitation and sexual work. The paper ends with a consideration about the still remaining doubts.

  9. [The psychologists in Argentina. Quantitative data].

    Science.gov (United States)

    Alonso, M M

    1994-03-01

    A partial report from a study dealing with Psychology's current status in Argentina is presented. Pursuant to this preliminary study 36,128 psychologists have taken their degree at both State and private universities in Argentina--between 1956, when the first Department of Psychology was created, and 1992. So, over a 32.5-million population (as per the 1991 census), there is a psychologist every 897 inhabitants, or 111 psychologists every 100,000 inhabitants. According to psychologists' geographical distribution, the highest density is to be found in the capital city of Buenos Aires (one psychologist every 246 inhabitants) while the lowest density is to be found in the Province of Chaco (one psychologist every 17,465 inhabitants). During year 1993, a total of 26,726 students have been studying Psychology at the different Argentine universities: Of these, 6,858 have taken their Psychology degree during this academic year. A great majority of psychologists work in the clinical field, being Psychoanalysis their prominent theoretical orientation. Ladies psychologists supposedly account for 85% of the overall number of psychologists. Psychological Associations have 24,878 active psychologists recorded, of which a great majority work in the clinical field.

  10. Difilobotriasis humana en la Patagonia, Argentina

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    Semenas Liliana

    1997-01-01

    Full Text Available OBJETIVO: El objetivo del trabajo fué detectar hospedadores humanos en la zona andino patagónica argentina, teniendo en cuenta las prácticas de pesca desportiva y la importancia de los salmónidos dentro de la zona. MATERIAL Y METODO: Entre 1986 y 1995 se implementaron Campañas de Información en los laboratorios de Análisis Clínicos de la región andinopatagónica argentina, destinadas a lograr una detección más eficiente de la difilobotriasis, a través de análisis coproparasitológicos. RESULTADOS: Adicionalmente, se confeccionaron planillas destinadas a recoger información sobre las características de la infección, del tratamiento y del paciente. Durante este período se detectaron 13 nuevos casos humanos, por identificación directa del parásito o por la presencia de huevos en materia fecal. Las características de las infecciones responden a las descriptas para el género Diphyllobothrium. CONCLUSIONES: En la región, los salmónidos son los peces predilectos en la pesca deportiva. Estos peces, frecuentemente parasitados con larvas, constituyen la principal fuente de contagio para el hombre al ser consumidos insuficientemente cocidos o ahumados en frío.

  11. Difilobotriasis humana en la Patagonia, Argentina

    Directory of Open Access Journals (Sweden)

    Liliana Semenas

    1997-06-01

    Full Text Available OBJETIVO: El objetivo del trabajo fué detectar hospedadores humanos en la zona andino patagónica argentina, teniendo en cuenta las prácticas de pesca desportiva y la importancia de los salmónidos dentro de la zona. MATERIAL Y METODO: Entre 1986 y 1995 se implementaron Campañas de Información en los laboratorios de Análisis Clínicos de la región andinopatagónica argentina, destinadas a lograr una detección más eficiente de la difilobotriasis, a través de análisis coproparasitológicos. RESULTADOS: Adicionalmente, se confeccionaron planillas destinadas a recoger información sobre las características de la infección, del tratamiento y del paciente. Durante este período se detectaron 13 nuevos casos humanos, por identificación directa del parásito o por la presencia de huevos en materia fecal. Las características de las infecciones responden a las descriptas para el género Diphyllobothrium. CONCLUSIONES: En la región, los salmónidos son los peces predilectos en la pesca deportiva. Estos peces, frecuentemente parasitados con larvas, constituyen la principal fuente de contagio para el hombre al ser consumidos insuficientemente cocidos o ahumados en frío.

  12. Brucellosis in buffalos from Corrientes northeast (Argentina

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    G. Crudeli

    2010-02-01

    Full Text Available Buffalo’s production represents an important option as input source in livestock systems located in areas with little profitability by cattle. In mostly farms, cattle and buffalos are breeding together, due that in Argentina, to carry out buffalo’s production is in an extensive way, with the aim to produce meat – mostly- milk – for this production nutritional supplements are used- and leathers. Brucellosis is zoonic illnesses from bacteria belong to Brucella which caused human human health problems by contaminated food ingestion or to those who are in touch with cattle. In Argentina, exist the National Control an Elimination Program for cattle Brucellosis, which include buffalos also, there is inclosed female vaccination and serologic segregation of positive reactants. Diagnosis techniques ruled for cattle brucellosis are BPA (Buffered Plate Agglutination, Tube seroaglutination and 2MercaptoEthanol. International reference test is Complement Fixation. By means of this present work, we pretend to evaluate the serologic diagnosis utility, ruled to the buffalos and compare obtained results by BPA, SAT and 2ME with Complement Fixation Test. In the present communication are presented results from the use of diagnosis techniques recommended by SENASA (National Service of Sanity and Quality Agro-Food to buffalo’s serums which belong to nine farms from NE Corrientes State. Obtained results show that association o BPA as Screening Test and SAT and 2ME as Confirmated Test has a valid correlation for the detection of positive animals with the reference technique Complement Fixation.

  13. Ten years of SLR production in Argentina

    Science.gov (United States)

    Pacheco, A.; Podestá, R.; Yin, Z.; Liu, W.; Actis, E.; Adarvez, S.; Quinteros, J.; Podestá, F.

    2017-07-01

    SLR technique is a proved astro-geodetic art with a significant power to contribute to Earth and Space Sciences. Therefore, scientific applications of SLR System are able to perform multiple tasks in the fields of Astrometry, Geodesy and Geophysics. The results we show here were obtained from satellite observations made at SLR 7406 Station of Observatorio Astronómico Félix Aguilar (OAFA) in San Juan, Argentina. The telescope was installed early on 2006, in concordance with an International Cooperation Agreement between Universidad Nacional de San Juan, Argentina and Chinese Academy of Sciences. In this abstract we show the current research being done with ILRS 7406 station: Length of day (LOD) and Angular velocity of Earth Rotation, calculated weekly; Pole Motion. ILRS7406 is daily surveying Pole coordinates x and y; Tracking SLR to GNSS constellations. SLR System contributes to the adjustment and validation of satellite GALILEO, GPS, GLONASS, and BEIDOU orbits. Our station is nowadays member of the new ITRF 2014 frame, and these past years has been one of the 3 highest producing SLR Stations on the ILRS net, composed of about 40 stations distributed all around the world. The obtained results during this first 10 years of experience are useful to enhance the traditional collaboration between OAFA and international services such as ILRS, IERS and NASA.

  14. Age and geochemistry of Alumine's Ignimbrites, Neuquen province, Argentina

    International Nuclear Information System (INIS)

    Lagorio, Silvia; Massaferro, Gabriela

    1998-01-01

    Geochemical and geochronological data from Alumine riolitic welded tuffs are analysed. Minor elements show enrichment in Rb, Th and K and depletion in Nb, Ti, P and Sr. La/Yb ratios are low. The geochemical features are consistent with a volcanic arc genesis. The radiometric data obtained by K/Ar method point out a Paleocene age for these rocks, allowing to correlate them with the Ventana Formation or the equivalent Auca Pan Formation. (author)

  15. Overview and perspectives for Open Access development in Argentina

    Directory of Open Access Journals (Sweden)

    Sandra Miguel

    2013-04-01

    Full Text Available This paper provides an overview and perspectives for development of the Open Access movement in Argentina, within the global and regional (Latin American context. It outlines the evolution and current state of initiatives around the two main approaches to Open Access, the golden and green roads. The main Open Access policies and support of OA movement by governments in Latin American region, and particularly in Argentina, are highlighted, while recent studies on publishing practices and authors’ positions regarding Open Access are presented. The paper concludes that the prospects for development of OA in Argentina, both through golden and green roads are favorable, with their strengths and shortcomings

  16. Geochemical and geochronological constrains on the Chiang Khong volcanic rocks (northwestern Thailand) and its tectonic implications

    Science.gov (United States)

    Qian, Xin; Feng, Qinglai; Chonglakmani, Chongpan; Monjai, Denchok

    2013-12-01

    Volcanic rocks in northwestern Thailand exposed dominantly in the Chiang Khong area, are commonly considered to be genetically linked to the tectonic evolution of the Paleo-Tethyan Ocean. The volcanic rocks consist mainly of andesitic to rhyolitic rocks and are traditionally mapped as Permian-Triassic sequences. Our zircon U-Pb geochronological results show that two andesitic samples (TL-1-B and TL-31-B), are representative of the Doi Yao volcanic zone, and give a mean weighted age of 241.2±4.6 Ma and 241.7±2.9 Ma, respectively. The rhyolitic sample (TL-32-B1) from the Doi Khun Ta Khuan volcanic zone erupted at 238.3±3.8 Ma. Such ages indicate that Chiang Khong volcanic rocks erputed during the early Middle Triassic period. Seven samples from the Doi Yao and Doi Khun Ta Khuan zones exhibit an affinity to arc volcanics. Three rhyolitic samples from the Chiang Khong area have a geochemical affinity to both arc and syn-collisional volcanic rocks. The Chiang Khong arc volcanic rocks can be geochemically compared with those in the Lampang area in northern Thailand, also consistent with those in Jinghong area of southwestern Yunnan. This indicates that the Chiang Rai arc-volcanic zone might northwardly link to the Lancangjiang volcanic zone in southwestern China.

  17. U-Pb zircon geochronology in the western part of the Rayner Complex, East Antarctica

    International Nuclear Information System (INIS)

    Horie, Kenji; Hokada, Tomokazu; Motoyoshi, Yoichi; Shiraishi, Kazuyuki; Takehara, Mami; Hiroi, Yoshikuni

    2016-01-01

    U-Pb zircon geochronology was applied to nine metasedimentary samples collected from Mt. Yuzhnaya, Condon Hills, and Mt. Lira in the inland region of the Rayner Complex of western Enderby Land, East Antarctica, in order to define the eastern limits of the western Rayner Complex that underwent the Pan-African metamorphism and to evaluate potential source areas of metasedimentary rocks. Condon Hills and Mt. Lira revealed metamorphic ages of ∼ 894 and ∼ 934 Ma, respectively, which are consistent with previously reported metamorphism in association with Rayner Structural Episode (RSE). Mt. Yuzhnaya samples affected by the RSE contain zircon grains rejuvenated during 590-570 Ma, which indicates that the Pan-African reworking can be extended up to Mt. Yuzhnaya. On the other hand, the Condon Hills samples include Archean detritus, and the age peaks from 3850 to 2491 Ma are the oldest components in the Rayner Complex of western Enderby Land. There is no evidence of reworked Napier Complex rocks in the studied Rayner samples. (author)

  18. Geochronological study of the metaconglomerates of the Sao Roque Group, Sao Paulo State

    International Nuclear Information System (INIS)

    Tassinari, C.C.G.; Kawashita, K.; Kikuchi, R.K.P. de

    1985-01-01

    This work deals with the geochronological study of the metaconglomerates of the Sao Roque Group by Rb-Sr whole rock measurements and K-Ar method in minerals concentrate. The granite-gneissic pebbles from the metaconglomerates have been analysed by Rb-Sr isochronic method and yelded an age of 1200+100 Ma. with a 87 Sr/ 86 Sr intercept of 0.737 +- 0.003. In our view this age might be associated to the metamorphic episode affecting the pre-existent granitic rocks before the epoch of the Sao Roque group sedimentation, or to the original age of the pebbles. The analytical points from the conglomerate matrix seem to define a linear array with 800Ma. This age, probably, represents the epoch of the main metamorphic event on the Sao Roque Group. The K-Ar micas determinations on rocks of the unit in study are concordant in ages, with values around 620.. These ages represent the tectonic estabilization epoch of the Pico de Jaragua region. (Author) [pt

  19. The Lathrop Wells volcanic center: Status of field and geochronology studies

    International Nuclear Information System (INIS)

    Crowe, B.; Morley, R.; Wells, S.; Geissman, J.; McDonald, E.; McFadden, L.; Perry, F.; Murrell, M.; Poths, J.; Forman, S.

    1992-01-01

    The purpose of this paper is to describe the status of field and geochronology studies of the Lathrop Wells volcanic center. Our perspective is that it is critical to assess all possible methods for obtaining cross-checking data to resolve chronology and field problems. It is equally important to consider application of the range of chronology methods available in Quaternary geologic research. Such an approach seeks to increase the confidence in data interpretations through obtaining convergence among separate isotopic, radiogenic, and age-correlated methods. Finally, the assumptions, strengths, and weaknesses of each dating method need to be carefully described to facilitate an impartial evaluation of results. The paper is divided into two parts. The first part describes the status of continuing field studies for the volcanic center for this area south of Yucca Mountain, Nevada. The second part presents an overview of the preliminary results of ongoing chronology studies and their constraints on the age and stratigraphy of the Lathrop Wells volcanic center. Along with the chronology data, the assumptions, strengths, and limitations of each methods are discussed

  20. A flavor of 40Ar-39Ar geochronology research at lIT Bombay

    International Nuclear Information System (INIS)

    Pande, Kanchan

    2017-01-01

    Geochronology based on radiogenic isotopes has become an invaluable tool in earth sciences. Several radioactive parent-daughter systems of varying half-lives such as Rb-Sr, Sm-Nd, K-Ar have been traditionally used by researchers for determining the timing of geological and planetary processes. 40 Ar- 39 Ar dating, a variant of the K-Ar system, is a well-established and versatile method of determining the eruptive ages of volcanic rocks and the ∼150-500° C thermal histories of a variety of more slowly cooled igneous and metamorphic rocks. In the 40 Ar- 39 Ar method the sample is irradiated by fast neutrons in a nuclear reactor to convert some of 39 K into 39 Ar. The fixed natural ratio 39 K/ 40 K provides estimate for the parent 40 K by measuring 39 Ar. In order to know the conversion factor of 39 K to 39 Ar and to take care of other nuclear interfering reactions a sample of known K-Ar age is irradiated along with the unknown. The age of the unknown is then derived by comparison with the monitor sample of known age

  1. Study on geochronology and uranium source of sandstone-type uranium deposit in Dongsheng area

    International Nuclear Information System (INIS)

    Liu Haibin; Xia Yuliang; Tian Shifeng

    2007-01-01

    This paper studied the geochronology of sandstone-type uranium deposit in the Dongsheng area of Ordos Basin. In eastern segment, ages of mineralization at the wing of the ore-roll are found to be 120 ± 5 Ma and 80 ± 5 Ma, and at the front of the ore-roll are 20 ± 2 Ma and 8 ± 1 Ma; While in middle segment, ages of mineralization are 124 ± 6 Ma and 80 ± 5 Ma. This means that the main mineralization in Dongsheng area were formed at early Jurassic and late Cretaceous, and correspondent to the time of structure uplift. Mineralization of roll-front (rich ore) which formed in Miocene and Pliocene may related to tectonic-thermal event taken place at that time and reformed the early mineralization in this area. The isochron line age of sample with uranium grade 0 ) in the sandbody is 24.64 x 10 -6 also shows the uranium pre-concentration in the strata. The even value of ΔU of rocks in Zhiluo formation is -70.2%, this shows that non-mineralized rocks have migrated uranium and acted as important metallogenic uranium sources. (authors)

  2. Contribution for geochronological evolution study of the Pianco-Alto Brigida fold belt system

    International Nuclear Information System (INIS)

    Brito Neves, B.B. de; Basei, M.A.S.; Van Schmus, W.R.

    1990-01-01

    The Proterozoic Painco-Alto Fold Belt is situated in the central portion of the Borborema Province and it probably is just a segment of a longer structural development encompassed between the Patos (N) and Pernambuco (S) lineaments. The geochronological study was carried out along a cross section in the central part of the belt (Paraiba State) where biotite-muscovite quartz schists are the predominating rock types, including intercalations of bi-modal volcanics, marbles and quartzites. These rocks were metamorphosed in the amphibolite facies, and they display a complex history of folding. Zircons of the acid volcanics (meta-rhyolytes where analysed through U/Pb method and they plot in a discordia diagram with superior intercept indicating ages around 1100 Ma. Whole rocks Rb/Sr analyses on the same meta-volcanics are indicating isochrons of 950Ma. These data are being respectively interpreted as ages of sedimentation (and volcanism) and regional metamorphism associated to the main (D sub(2)) phase of folding. One of the main purpose of this paper is to stress the importance of the ages around 950Ma, in the central domain of the Borborema Province, as result of regional folding and metamorphism. Some other occurence of ages in the 1000-900Ma range will be discussed as support for this interpretation from now on adopted. (author)

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

    Science.gov (United States)

    Mclelland, J. M.

    1988-01-01

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

  4. Magmatic tempo of Earth's youngest exposed plutons as revealed by detrital zircon U-Pb geochronology.

    Science.gov (United States)

    Ito, Hisatoshi; Spencer, Christopher J; Danišík, Martin; Hoiland, Carl W

    2017-09-29

    Plutons are formed by protracted crystallization of magma bodies several kilometers deep within the crust. The temporal frequency (i.e. episodicity or 'tempo') of pluton formation is often poorly constrained as timescales of pluton formation are largely variable and may be difficult to resolve by traditional dating methods. The Hida Mountain Range of central Japan hosts the youngest exposed plutons on Earth and provides a unique opportunity to assess the temporal and spatial characteristics of pluton emplacement at high temporal resolution. Here we apply U-Pb geochronology to zircon from the Quaternary Kurobegawa Granite and Takidani Granodiorite in the Hida Mountain Range, and from modern river sediments whose fluvial catchments include these plutons in order to reconstruct their formation. The U-Pb data demonstrate that the Kurobegawa pluton experienced two magmatic pulses at ~2.3 Ma and ~0.9 Ma; whereas, to the south, the Takidani pluton experienced only one magmatic pulse at ~1.6 Ma. These data imply that each of these magmatic systems were both spatially and temporally distinct. The apparent ~0.7 Myr age gap between each of the three magmatic pulses potentially constrains the recharge duration of a single pluton within a larger arc plutonic complex.

  5. Extension of 239+240Pu sediment geochronology to coarse-grained marine sediments

    Science.gov (United States)

    Kuehl, Steven A.; Ketterer, Michael E.; Miselis, Jennifer L.

    2012-01-01

    Sediment geochronology of coastal sedimentary environments dominated by sand has been extremely limited because concentrations of natural and bomb-fallout radionuclides are often below the limit of measurement using standard techniques. ICP-MS analyses of 239+240Pu from two sites representative of traditionally challenging (i.e., low concentration) environments provide a "proof of concept" and demonstrate a new application for bomb-fallout radiotracers in the study of sandy shelf-seabed dynamics. A kasten core from the New Zealand shelf in the Southern Hemisphere (low fallout), and a vibracore from the sandy nearshore of North Carolina (low particle surface area) both reveal measurable 239+240Pu activities at depth. In the case of the New Zealand site, independently verified steady-state sedimentation results in a 239+240Pu profile that mimics the expected atmospheric fallout. The depth profile of 239+240Pu in the North Carolina core is more uniform, indicating significant sediment resuspension, which would be expected in this energetic nearshore environment. This study, for the first time, demonstrates the utility of 239+240Pu in the study of sandy environments, significantly extending the application of bomb-fallout isotopes to coarse-grained sediments, which compose the majority of nearshore regions.

  6. Rb-Sr geochronology from Sao Felix to Xingu: preliminary results

    International Nuclear Information System (INIS)

    Lafon, J.M.; Pereira, E.D.; Silva Barradas, J.A. da

    1991-01-01

    Rb-Sr systematics have been applied on rocks from the Sao Felix do Xingu region, in the southeastern part of the State of Para. An age of 2716 ± 34 Ma with IR of 0.70292 ± 0.00030 (MSWD = 1.54) and an age of 2677 ± 50 Ma with IR of 0.70161 ± 0.00022 (MSWD = 5.21) had been obtained for a granitic body and a tonalitic body respectively, both of them associated to the green stones belts that occur in this area. Gneisses from the Xingu complex gave an age of 2574 ± 57 Ma with an IR of 0.70416 ± 0.00054 (MSWD = 5.06). An age of 1653 ± 14 Ma with IR of 0.70823 ± 0.02361 (MSWD = 1.71) had been obtained for the Velho Guilherme granite that crosscut the granite-green stones terrains. Such geochronological data show the existence of a magmatic event between 2.72 Ga and 2.68 Ga and permit us to conclude on the archaean age of the green stones terrains. (author)

  7. Sedimentation rates and depositional processes in Lake Superior from 210Pb geochronology

    International Nuclear Information System (INIS)

    Evans, J.E.; Johnson, T.C.; Alexander, E.C. Jr.; Lively, R.S.; Eisenreich, S.J.

    1981-01-01

    Sedimentation rates range from 0.01 to 0.32 cm/yr in 17 sediment box cores from Lake Superior, as determined by 210 Pb geochronology. Shoreline erosion and resuspension of nearshore sediments causes moderate to high (0.05-0.11 cm/yr) sedimentation rates in the western arm of Lake Superior. Sedimentation rates are very high (> 0.15 cm/yr) in marginal bays adjoining Lake Superior; and moderate to very high (0.07-0.19 cm/yr) in open lake regions adjacent to marginal bays. Resuspension of nearshore and shoal top sediments in southern and southeastern Lake Superior by storms is responsible for depositional anomalies in 210 Pb profiles corresponding to 1905, 1916-1918, and 1940 storms. Sedimentation rates are very low (0.01-0.03 cm/yr) in the central basins due to isolation from sediment sources. These data indicate that sedimentation rates and processes vary significantly in different regions of Lake Superior. The sedimentation rates provided by this study, in conjunction with previously-reported sedimentation rates, yield a better understanding of the Lake Superior depositional environment

  8. The precambrian of the Anti-Atlas (Morocco): a geochronological synthesis

    International Nuclear Information System (INIS)

    Charlot, Rene

    1976-01-01

    Twenty total-rock Rb/Sr isochrons (lambda 87 Rb=1.47x10 -11 yr 1 ) and many individual data, mainly obtained by the K/Ar and Rb/Sr methods, on total rocks and minerals show that the orogenic story of the Precambrian of the Anti-Atlas, which was studied in its western and central parts, began with the Eburnean orogeny (1900-1650 m.y.). Up to now there is no good evidence of an older basement, even if the rather high initial ratio (0.707-0.709) of some Eburnean granites might suggest that such a basement exists at depth. There is also no geochronological evidence of plutonism until in early Panafrican time (680 m.y.) there started a period of intense magmatic and thermal activity which was ended by the emplacement of late post-tectonic granites at 530-520 m.y. The late Panafrican acid volcanism does not generally give suitable material for Rb/Sr dating, because of the great mobility of the radiogenic strontium in such a material even under very weak thermal conditions

  9. The metamorphic basement of the Cordillera Frontal of Mendoza: New geochronologic and isotopic data

    International Nuclear Information System (INIS)

    Basei, Miguel; Ramos, Victor A.; Vujovich, Graciela I.; Poma, Stella

    1998-01-01

    The metamorphic rocks of the Cordillera Frontal exposed in the Cordon del Portillo, Mendoza were examined by Rb/Sr geochronology and Nd/Sm isotopic analysis. The Rb/Sr data defined a Devonian age for the last metamorphic episode, similar to the previous K/Ar and Ar/Ar ages obtained in this region and western Precordillera. The isotopic analysis identified three sets of model ages: 1.- The oldest corresponds to a set of meta sedimentary rocks with a model age of 1,400 to 1,700 Ma; 2.- A monzogranodiorite with a model age of 1,000 Ma; and 3.- Metabasites with model ages between 577 and 330 Ma. These rocks are interpreted as 1.- A typical Grenvillian derived basement; 2.- Late Paleozoic granitoids derived from a different Proterozoic basement; and 3.- Some Eopaleozoic metabasites tectonically inter fingered with the Grenvillian basement. These new data are coherent with the existence of a Laurentia derived terrane, Chilenia, that was separated by oceanic rocks from the basement of Pre cordillera during Eopaleozoic times. This last basement known as the Cuyania terrane, was also derived from Laurentia. (author)

  10. Geochronology and Geomorphology of the Pioneer Archaeological Site (10BT676), Upper Snake River Plain, Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Keene, Joshua L. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-04-01

    The Pioneer site in southeastern Idaho, an open-air, stratified, multi-component archaeological locality on the upper Snake River Plain, provides an ideal situation for understanding the geomorphic history of the Big Lost River drainage system. We conducted a block excavation with the goal of understanding the geochronological context of both cultural and geomorphological components at the site. The results of this study show a sequence of five soil formation episodes forming three terraces beginning prior to 7200 cal yr BP and lasting until the historic period, preserving one cultural component dated to ~3800 cal yr BP and multiple components dating to the last 800 cal yr BP. In addition, periods of deposition and stability at Pioneer indicate climate fluctuation during the middle Holocene (~7200-3800 cal yr BP), minimal deposition during the late Holocene, and a period of increased deposition potentially linked to the Little Ice Age. In addition, evidence for a high-energy erosion event dated to ~3800 cal yr BP suggest a catastrophic flood event during the middle Holocene that may correlate with volcanic activity at the Craters of the Moon lava fields to the northwest. This study provides a model for the study of alluvial terrace formations in arid environments and their potential to preserve stratified archaeological deposits.

  11. Sediment accumulation rates and geochronologies measured in the Saguenay Fjord using the Pb-210 dating method

    Energy Technology Data Exchange (ETDEWEB)

    Smith, J N; Walton, A [Department of Fisheries and Oceans, Dartmouth, N.S. (Canada). Atlantic Oceanographic Lab., Bedford Inst. of Oceanography

    1980-02-01

    Sediment accumulation rates were estimated from the vertical distribution of excess Pb-210 measured in sediment cores collected at seven stations in the Saguenay Fjord, Quebec. These rates decrease with increasing water depth and distance from the mouth of the Saguenay River, ranging from 4.0 g cm/sup -2/yr/sup -1/ (approximately = 7 cm yr/sup -1/) near the head of the fjord to 0.07 g cm/sup -2/yr/sup -1/ (approximately 0.1 cm yr/sup -1/) in the deep inner basin of the fjord. In one core from the head of the fjord, layered sediment structures, having different physical characteristics and composition, appear related to recent pulsed inputs of older raised marine deposits displaced by a landslide in 1971. Synchronous depositional anomalies in several cores provide evidence of other large scale sediment redistribution processes in the fjord. Pb-210 geochronologies are generally in good agreement with time-stratigraphic horizons inferred both from Cs-137 activity profiles and from the analysis of pollen assemblages in one core. (author).

  12. 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)

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

    O2, Sr, V, and Sc and increasing values for Na2O, K2O, Ba, Rb, and Zr with increasing silica. Samples from the megabreccia can be chemically distinguished from the younger rocks of this center. Petrologic models suggest that the younger rocks from the Grand Soufriere Hills can be produced by fractional crystallization of basaltic magma such as those erupted from other centers (such as Morne Anglais to the west). Minor variations within this suite of andesites can be related to upper crustal fractionation of phenocryst phases.

  3. 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.)

  4. 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

  5. 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

  6. Tabaquismo durante el embarazo en Argentina y Uruguay Smoking during pregnancy in Argentina and Uruguay

    Directory of Open Access Journals (Sweden)

    Fernando Althabe

    2008-02-01

    Full Text Available Argentina y Uruguay están entre los países con mayor proporción de mujeres jóvenes fumadoras. Se desconoce cuál es la proporción exacta de ellas que fuman durante el embarazo así como las características de las que dejan de fumar y las que continúan fumando durante el embarazo. Realizamos una encuesta administrada por un/a entrevistador/a a 1512 mujeres embarazadas de 18 años o mayores (796 en Argentina; 716 en Uruguay, que concurrían a control prenatal en hospitales públicos de grandes conglomerados urbanos. 44% de las mujeres en Argentina y 53% en Uruguay habían sido o eran fumadoras. Durante el embarazo, 11% de las mujeres en Argentina y 18% en Uruguay continuaron fumando. En ambos países, la proporción de mujeres que vive con fumadores, permite fumar en el hogar y regularmente o siempre se encuentra en lugares cerrados con personas que estén fumando fue 49%, 46% y 20% entre las mujeres que nunca fumaron, 67%, 60% y 32% entre las que dejaron, y 78%, 75% y 52% entre las que continuaron fumando respectivamente. El estudio confirma un importante problema de salud pública y documenta que la exposición ambiental persiste en subgrupos de mujeres, aun en aquéllas que dejaron de fumar. Es importante que el sector de salud pública provea acceso a programas efectivos para dejar de fumar durante el embarazo. Cualquier nueva intervención a desarrollar que intente tener un éxito al menos moderado y sostenible, debiera incluir componentes que actúen sobre el entorno fumador de la mujer embarazada que fuma.Argentina and Uruguay are among the countries in which a large proportion of young women smoke. The rate of smokers during pregnancy in both countries is not well known, and data on the characteristics of women who quit smoking during pregnancy compared to those who continue smoking are not available. We conducted a survey including 1512 pregnant women >18 years old (796 in Argentina; 716 in Uruguay, during antenatal visits in

  7. Geochronological constraints on Cretaceous-Paleocene volcanism in South Westland, New Zealand

    International Nuclear Information System (INIS)

    Phillips, C.J.; Cooper, A.F.; Palin, J.M.; Nathan, S.

    2005-01-01

    Cretaceous and Paleocene sedimentation in South Westland, New Zealand, is recorded in the Otumotu Formation, Tauperikaka Coal Measures, Whakapohai Sandstone, Arnott Basalt, Buttress Conglomerate, and Tokakoriri Formation, originally named and mapped by Nathan in 1977. Within this stratigraphic sequence, the name Buttress Conglomerate was used to describe volcanic conglomerates at Porphyry and Buttress Points that contained rounded clasts of plagioclasephyric intermediate volcanic rocks. Stratigraphically, the volcanic conglomerate at Porphyry Point forms sharp contacts with the underlying Arnott Basalt (Haumurian) and overlying Tokakoriri Formation (Teurian). The volcanic conglomerate at Buttress Point, however, is entirely fault-bounded. Clasts from each unit were collected and U-Pb zircon dated using the TIMS and ELA-ICP-MS methods. A trachyandesite clast collected at Buttress Point gives an age of 96.9 ± 1.6 Ma, whereas a rhyolite clast collected at Porphyry Point gives an age of 61.4 ± 0.8 Ma. Petrological, geochemical, and stratigraphic data suggest that erosion of the clasts closely followed volcanism, and that these ages accurately reflect the depositional ages of the conglomerates. Conglomerates at Porphyry and Buttress Points have been formally renamed the Porphyry Point Member of the Tokakoriri Formation and the Buttress Point Conglomerate, respectively. (author). 49 refs., 7 figs., 4 tabs

  8. Measurements of atmospheric fallout in Argentina; Determinacion del fallout atmosferico en la Republica Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Canoba, A C; Lopez, F O; Bruno, H A

    1998-11-01

    With the purpose of studying the radioactive fallout present in Argentina from atmospheric nuclear explosions tests that have been conducted recently, an environmental monitoring program, outside the influence of nuclear facilities of Argentina, was undertaken during 1996 and 1997. The levels of Cs-137 and Sr-90 were analysed in samples of air, deposited material (rainwater), milk, an average meal of a standard man and food. During this period, a total of 630 radiochemical analysis were performed on 325 samples of the different matrices described. The concentration levels of the radionuclides analysed in the different environmental matrices are presented and are compared with the values obtained in the environmental monitoring program done during the period 1960-1981. (author) 3 refs., 9 tabs. [Espanol] Con el proposito de estudiar la precipitacion radiactiva presente en la Republica Argentina, debido al ensayo de armas nucleares en la atmosfera realizadas en el pasado, se implemento el muestreo ambiental fuera de la zona de influencia de las instalaciones nucleares de la Argentina durante los anios 1996 y 1997. Se determinaron las concentraciones de cesio 137 y estroncio 90 en muestras de aire, deposito de material radiactivo (agua de lluvia), leche, dieta promedio de un individuo estandar y en alimentos varios. Se realizaron, durante el periodo mencionado, un total de 630 determinaciones radioquimicas sobre 325 muestras de las diferentes matrices mencionadas. Se presentan los niveles de concentracion de los radionucleidos analizados en las distintas matrices ambientales y se comparan los valores obtenidos en los monitoreos realizados durante el periodo 1960-1981. (autor)

  9. Synsedimentary ash rains and paleoenvironmental conditions during the deposition of the Chachil Formation (Pliensbachian) at its type locality, Neuquén Basin, Argentina

    Science.gov (United States)

    Armella, Claudia; Leanza, Héctor A.; Corfu, Fernando

    2016-11-01

    A detailed sedimentological analysis of the so called "Chachil Limestones" at its type locality around the Mirador del Chachil area, southwestern Neuquén province, Argentina, is presented in this paper for the first time. It is based on a macro/microfacial analysis and their environmental interpretation by means on texture, fabric, bioclasts, intrabasinal and extrabasinal grain amounts, sedimentary structures, bioturbations and hydro-dynamism. Because of the recognition of different facies associations, but no pure limestones, it is more suitable to refer these sediments as the Chachil Formation. The depositional environment of this unit is interpreted to correspond to an internal platform dominated by tides, with carbonate sedimentation disturbed by repeated explosive volcanic episodes, which reduced the sedimentation space, causing retrogradation of the sedimentary system and coastal onlap. In addition, a new recalibration of the U-Pb zircon dating used for the geochronological analysis reveals a small change with regard to previous information that has been used to recalculate the data, is presented in this paper.

  10. Archean and proterozoic in the West-European Hercynian chain: isotopic geochemistry (Sr-Nd-Pb) and U-Pb geochronology on zircons

    International Nuclear Information System (INIS)

    Guerrot, C.

    1989-01-01

    The first part of this research thesis reports the study of isotopic (Sr-Nd-Pb) geochemistry and U-Pb geochronology on zircons in the immersed granulites of the Bay of Biscay: U-Pb geochronology on zircons, Nd isotopic geochemistry, Sr isotopic geochemistry, common Pb, Rb-Sr, Sm-Nd and rare earth data on minerals, comparison with other European granulites, comparison with West-Africa, study of Archean and proterozoic in the Hercynian chain. The second part reports the study of the U-Pb geochronology on zircon in the Cadomian, and the third part addresses the Sr-Nd isotopic geochemistry of some Cadomian granitoid, and the crust contamination in different regions [fr

  11. Radioactive waste with 14C in Argentina

    International Nuclear Information System (INIS)

    Di Lello, D.S.

    2009-01-01

    14 C is a long half-life radioisotope, which is present in radioactive waste generated during the operation and decommissioning of nuclear power plants. 14 C can also be found in waste generated by medical diagnostic laboratories or any one generated by fields that deal with research and development (mainly connected with the biochemists area). According to international precedents the disposal of 14 C based on the final amount found in radioactive waste and its chemical form have conditioned the design and operation of the facilities (either because of the amount of it or the chemical form in which 14 C was present). We have to take into account that the design of facilities for radioactive waste disposal is included among the obligations of the National Radioactive Waste Management Program (PNGRR). It is absolutely necessary to count with enough information about the characteristics of any waste containing 14 C that is generated in Argentina, in order to be able to fulfil the requirements previously mentioned. The main characteristics of interest in the frame of the present project are: a) the principal reactions that take place for the formation of 14 C; b) The specific concentration of activity in materials where this radio nuclei is formed or is accumulated; c) To know which is the current step in the process of managing these wastes (in Argentina and all over the world). Either if it refers to bulk or conditioned storage, inside the generating facility; d) Transportation possibilities of 14 C under these conditions; e) The accumulated volume and the generation rate of this kind of waste in Argentina. This paper presents an initial collection and evaluation of the information related to the characteristics already mentioned, having gathered published material from the literature and information in the PNGRR up to this moment. The description of the characteristics of the radioactive waste containing 14 C from nuclear power plants, hospitals and research and

  12. Argentina's regulatory body: its communication activities

    International Nuclear Information System (INIS)

    Cesario, Pablo A.; Terigi, Gabriel E.

    2008-01-01

    Full text: The Nuclear Regulatory Authority of Argentina (ARN) is empowered to regulate and control the nuclear activity with regard to radiation and nuclear safety, physical protection and nuclear non-proliferation issues. It must also advise the Executive on issues under its purview. The objective of the Nuclear Regulatory Authority is to establish, develop and enforce a regulatory system applicable to all nuclear activities carried out in Argentina. Two of the goals of this regulatory system are to provide an appropriate standard of protection for individuals against the harmful effects of ionizing radiation, and to maintain a reasonable degree of radiological and nuclear safety in the nuclear activities performed in Argentina. The responsibility of the radiation protection community in performing the tasks to accomplish this goals is twofold. On one hand, it must ensure a high technical quality in performing these functions. It must also provide information on its activities which has to be accurate, comprehensive and understandable. The way a society understands the concept of 'risk' needs to be kept in mind. Risk perception is the subjective judgment that people make about the characteristics and severity of a risk. Cultural theory refers to theories of risk perception that focus on culture, rather than individual psychology as an explanation for differences in risk judgments. It is widely agreed that trust is a key factor in influencing people's perceptions of risk. It is understood there are two main ways trust may impact in risk perceptions: an activity is perceived as more risky if the people or agencies managing it are perceived as untrustworthy; and information presented by trusted sources is given more credibility than information from untrusted sources. One of the primary purposes of ARN's Communication Program is to provide a means whereby those engaged in radiation protection activities may communicate more readily with each other and the public and

  13. The obsidian from Quiron (Salta Province, Argentina): a new reference glass for fission-track dating

    Energy Technology Data Exchange (ETDEWEB)

    Bigazzi, G. [Istituto di Geoscienze e Georisorse, C.N.R., Area della Ricerca di Pisa, V.G. Moruzzi, 1, 56124 Pisa (Italy)]. E-mail: g.bigazzi@igg.cnr.it; Laurenzi, M.A. [Istituto di Geoscienze e Georisorse, C.N.R., Area della Ricerca di Pisa, V.G. Moruzzi, 1, 56124 Pisa (Italy); Viramonte, J.G. [Instituto Geonorte, Universidad Nacional de Salta and Conicet, Buenos Aires 177, 4400 Salta (Argentina)

    2005-12-01

    In the course of a geochronological study of the volcanic activity in the Andean Cordillera in northern Argentina, we have found in the El Quevar volcanic complex (24 deg. 19{sup '}S/66 deg. 43{sup '}W,6180m) a phenocryst poor obsidian (Quiron obsidian) showing an unusually high spontaneous track density. Defects which might produce 'spurious' tracks are virtually absent. Application of fission-track dating using an absolute approach, based on the IRMM-540 standard glass for neutron fluence measurements, yielded an apparent age of 7.27+/-0.29Ma(1{sigma}) and a plateau age of 8.99+/-0.31Ma(1{sigma}). A {sup 40}Ar-{sup 39}Ar isochron age on biotite of 8.61+/-0.04Ma(1{sigma}) was already available for the Quiron rhyolite. We determined further {sup 40}Ar-{sup 39}Ar ages on several chips of the glass itself using two analytical approaches: total fusion with a focussed laser beam (LTFA) and a step-heating approach using a de-focussed laser beam (LSHA). We have obtained a weighted average of 8.77+/-0.09Ma, an isochron age of 8.71+/-0.12Ma and an integrated age of 8.77+/-0.09Ma for LTF analyses, and a w.a. of 8.75+/-0.09Ma, an iso.a. of 8.77+/-0.09Ma and an int.a. of 8.77+/-0.09Ma for LSH analyses (all age errors are 2{sigma}). The Quiron obsidian is very easy to analyse for its high spontaneous track density and because microlites which might produce spurious tracks are very rare. Independent reference {sup 40}Ar-{sup 39}Ar ages determined in different laboratories are available. For these reasons we believe that this glass may be very useful for testing fission-track system calibrations and apparent age correction procedures. Splits of obsidian Quiron will be distributed upon request to colleagues who intend to test it.

  14. 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

  15. The multiple applications of the nuclear techniques in Argentina

    International Nuclear Information System (INIS)

    Manzini, Alberto C.

    2001-01-01

    A review is given of the use of nuclear technology in Argentina, especially in the field of the production of radioisotopes and radiopharmaceuticals, nuclear medicine, and industrial applications. The applications of ionizing radiation are also reviewed

  16. All projects related to Argentina | Page 8 | IDRC - International ...

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

    Health Financing, Equity and Poverty in Latin America ... Region: North and Central America, South America, Argentina, Brazil, Chile, Colombia, Costa ... one of the most serious but least publicized public health problems in Latin America.

  17. The bloodsucking biting midges of Argentina (Diptera: Ceratopogonidae

    Directory of Open Access Journals (Sweden)

    Gustavo R Spinelli

    2005-04-01

    Full Text Available A key is presented for the identification of the adults of 54 species of bloodsucking ceratopogonids, 51 of which are known inhabitants of Argentina, and Culicoides uruguayensis Ronderos, C. pifanoi Ortiz, and C. trilineatus Fox, which are known to occur in bordering Uruguay and Paraguay. Wing photographs are provided of females of the 45 species of Culicoides. Three new species of Culicoides Latreille from Northeastern Argentina are described and illustrated: C. austroparaensis Spinelli, C. bachmanni Spinelli, and C. williamsi Spinelli. The following six species are recorded for the first time from Argentina and/or bordering localities in Paraguay: Leptoconops brasiliensis (Lutz, C. gabaldoni Ortiz, C. ginesi Ortiz, C. pifanoi Ortiz, C. pseudocrescentis Tavares and Luna Dias, and C. trilineatus; and C. estevezae Ronderos and Spinelli is newly recorded from Misiones province of Argentina. C. lopesi Barretto is excluded from the Argentinean ceratopogonid fauna.

  18. Bolivia's gas heads for Brazil as Argentina waits - and watches

    International Nuclear Information System (INIS)

    Knight, P.

    1998-01-01

    The first 1,800 km stretch of a 3,400 km natural gas pipeline from Bolivia to Brazil will start operating in December. First planned 50 years ago, the pipeline has long been expected to result in an immediate surge of gas use in Brazil. However, impending deep recession in Brazil makes this prospect less likely despite the power shortages which indicate the need for considerable gas imports. Initially, most Bolivian gas will flow through Brazil to Argentina. But gas production is expanding rapidly in Argentina and the supply contract with Bolivia ends in 1999. Plans are well advanced to build two gas lines into the south of the Brazil from Argentina. Ultimately, it is anticipated that Argentina, which has abundant reserves and a virtually saturated domestic market, will become the principal source of natural gas for Brazil. (UK)

  19. The regulatory control of radioactive sources in Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Rojkind, Roberto Hector [Autoridade Regulatoria Nuclear, Buenos Aires (Argentina)

    1997-12-31

    Argentina has been conducting nuclear activities for more than forty years, and as early as in 1956 established a Regulatory Authority. Procedures for compliance monitoring and enforcement have been in use in the regulatory control of radioactive sources, and regulatory standards and regulations had been set in Argentina, before the accident in Goiania. The conclusions drawn from that accident encouraged in Argentina the improvement of some regulatory procedures and helped to enhance the quality of the regulatory process. Therefore, the effectiveness of the control of spent radioactive sources has gradually increased, and enforcement actions to prevent radioactive sources ending up in the public domain improved. Some lessons learned in Argentina from the accident in Goiania and the main characteristics of an effective enforcement program helpful to prevent radiological accidents in industrial, medical, research and teaching uses of radioactive sources are presented. (author) 9 refs; e-mail: rrojkind at sede.arn.gov.br

  20. Argentina: Political and Economic Conditions and U.S. Relations

    National Research Council Canada - National Science Library

    Sullivan, Mark P

    2006-01-01

    Argentina's restructuring of over $100 billion in defaulted bond debt in June 2005 demonstrated the country's emergence from its 2001-2002 economic crisis that had caused severe stress on the political system...

  1. Nuclear safeguards in Brazil and Argentina: 25 years of ABACC

    Science.gov (United States)

    Kassenova, Togzhan

    2017-11-01

    As possessors of advanced nuclear technology, Brazil and Argentina bear special responsibility for helping the international community and neighbors in their region feel confident that their nuclear programs are peaceful, secure, and safe. Over the past 25 years, the Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) has played an indispensable role in strengthening such confidence by implementing nuclear safeguards in the two countries. Today, ABACC carries out safeguards inspections at a total of 76 nuclear facilities in Brazil and Argentina. This article describes how Brazil and Argentina view trends in the global nonproliferation regime and international nuclear safeguards, and explains how these trends relate to unique challenges and opportunities facing Brazil, Argentina, and ABACC.

  2. Tributación del Sector Transporte en Argentina

    OpenAIRE

    Ernesto Rezk

    2004-01-01

    El objetivo general es examinar la carga tributaria efectiva sobre los servicios y las inversiones en infraestructura en los sectores de actividad del Transporte de Carga Terrestre (por camión) y Aéreo en la Argentina.

  3. The heavy water production plant at Arroyito, Argentina

    International Nuclear Information System (INIS)

    Ecabert, R.

    1984-01-01

    The author describes the construction of an industrial heavy water production plant (Planta Industrial de Agua Pesada, PIAP) in Argentina. The heavy water enrichment is based on a hydrogen/ammonia isotope exchange. (Auth.)

  4. Urban agriculture: Rosario, Argentina reaps the benefits | IDRC ...

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

    2010-10-06

    Oct 6, 2010 ... Urban agriculture: Rosario, Argentina reaps the benefits ... Urban agriculture has become a permanent part of the city's fabric, ... The Global Roundtable of Chief Economists highlights global trends and best practices to help ...

  5. All projects related to Argentina | IDRC - International Development ...

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

    Program: Governance and Justice ... Region: Argentina, Brazil, Chile, Costa Rica, Paraguay, Uruguay ... Program: Canada-Israel Health Research Program ... and Twitter are having a direct bearing on social inclusion and opportunity in many ...

  6. Record of Diaphorina citri (Hemiptera: Psyllidae) in North West Argentina

    OpenAIRE

    Augier, Lucrecia; Gastaminza, Gerardo; Lizondo, Marcelo; Argañaraz, Manuel; Willink, Eduardo

    2006-01-01

    Se amplía la distribución de Diaphorina citri Kuwayama (Hemiptera: Psyllidae) para el Noroeste Argentino.The distribution of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is expanded to North West Argentina.

  7. All projects related to argentina | IDRC - International Development ...

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

    Program: Governance and Justice ... Region: Argentina, Brazil, Chile, Costa Rica, Paraguay, Uruguay ... Program: Food, Environment, and Health ... and Twitter are having a direct bearing on social inclusion and opportunity in many spheres of ...

  8. The regulatory control of radioactive sources in Argentina

    International Nuclear Information System (INIS)

    Rojkind, Roberto Hector

    1997-01-01

    Argentina has been conducting nuclear activities for more than forty years, and as early as in 1956 established a Regulatory Authority. Procedures for compliance monitoring and enforcement have been in use in the regulatory control of radioactive sources, and regulatory standards and regulations had been set in Argentina, before the accident in Goiania. The conclusions drawn from that accident encouraged in Argentina the improvement of some regulatory procedures and helped to enhance the quality of the regulatory process. Therefore, the effectiveness of the control of spent radioactive sources has gradually increased, and enforcement actions to prevent radioactive sources ending up in the public domain improved. Some lessons learned in Argentina from the accident in Goiania and the main characteristics of an effective enforcement program helpful to prevent radiological accidents in industrial, medical, research and teaching uses of radioactive sources are presented. (author)

  9. 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...

  10. Aphanes arvensis (Rosaceae) en el extremo nordeste de la Argentina

    OpenAIRE

    Gustavo Hildt; Héctor A. Keller

    2017-01-01

    Se menciona por primera vez para el nordeste argentino a una hierba adventicia en el nuevomundo. La especie es ilustrada mediante fotografías Fil: Hildt, Gustavo. Universidad Nacional de Misiones; Argentina Fil: Keller, Hector Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina

  11. Allamanda schottii (Apocynaceae: nueva cita para la Flora Argentina

    Directory of Open Access Journals (Sweden)

    Julio A. Hurrell

    2013-01-01

    Full Text Available En este trabajo Allamanda schottii Pohl (Apocynaceae es documentada como nueva cita genérica y específica para la Flora Argentina. La especie fue hallada en la ribera del Paraná, en el norte de la provincia de Corrientes, Argentina. Se incluye su sinonimia, descripción, comentarios sobre su distribución, hábitat, fenología, biología reproductiva, nombres vulgares, usos y observaciones.

  12. CROSSROADS BETWEEN EDUCATION POLICIES AND INDIGENOUS LANGUAGES MAINTENANCE IN ARGENTINA

    Directory of Open Access Journals (Sweden)

    Ana Carolina Hecht

    2010-06-01

    Full Text Available Process of language shift is explained by many researchers since linguistic and anthropological perspectives. This area focuses on the correlations between social processes and changes in systems of use of a language. This article aims to address these issues. In particular, we analyze the links between educational-linguistic policy and the maintenance of the languages spoken in Argentina. In doing so, we explore this field taking into account the linguistic and educational policies implemented about indigenous languages in Argentina.

  13. Argentina's experience with parallel exchange markets: 1981-1990

    OpenAIRE

    Steven B. Kamin

    1991-01-01

    This paper surveys the development and operation of the parallel exchange market in Argentina during the 1980s, and evaluates its impact upon macroeconomic performance and policy. The historical evolution of Argentina's exchange market policies is reviewed in order to understand the government's motives for imposing exchange controls. The parallel exchange market engendered by these controls is then analyzed, and econometric methods are used to evaluate the behavior of the parallel exchange r...

  14. Sectorial analysis of nanotechnology companies in Argentina

    Science.gov (United States)

    Foladori, Guillermo; Lau, Edgar Záyago; Carroza, Tomás; Appelbaum, Richard P.; Villa, Liliana; Robles-Belmont, Eduardo

    2017-06-01

    In this paper, we identify 37 companies that produce nano-enabled products in Argentina. We locate the products of these firms in terms of both their economic sector and position in a value chain. The research was done through a four-step methodology. Firstly, an inventory of firms was created. Secondly, the firms were classified by their economic sector, following the United Nations economic classification. Thirdly, the firms were located within a simple nanotechnology value chain. Finally, the products were classified according to their final destination, being either means of production or final consumer products. The results show that healthcare, cosmetics, and medicine is the most represented sector along the value chain, followed by electronics.

  15. Adequacy features of Nucleoelectrica Argentina Safety Management

    Energy Technology Data Exchange (ETDEWEB)

    Rapoport, H [Nucleoelectrica Argentina S.A., Buenso Aires (Argentina)

    1997-12-01

    The Argentine Nuclear Power Plants (NPP) ATUCHA I (357 Mw, SIEMENS) and EMBALSE (648 Mw, CANDU), both of PHWR type, were owned and operated until August 94 by the Comision Nacional de Energia Atomica (CNEA). Until that date, CNEA, the national agency for nuclear R and D, concentrated three activities or roles: Research, Nuclear Regulations and NPP Operation. Since August 1994 NPP`s are owned and operated by a state electrical company (Nucleoelectrica Argentina S.A.) the nuclear utility supplying 15% of the national electrical generation demand. NASA is going to be privatized according to a recent national law regulating nuclear activities. The transition from a research agency to a commercial company requires the introduction of changes in the management of activities. Mention of these changes is limited to those relating to Safety.

  16. Evaluation of training activities in Argentina

    International Nuclear Information System (INIS)

    Sanda, Alejandro D.

    2003-01-01

    In Argentina, there are two NPPs in operation and one under construction. The personnel at the first NPP built, Atucha-1, were originally trained by the German experts, afterwards there were no serious problems while the plant was still new, but problems arose later, The training program organized locally was found to be 'frozen'. That is why experiences in evaluation of the training effectiveness will be of great help. The global training effectiveness are believed to be achieved if the following goals are reached: less number of non-planned shutdowns due to human errors; less number of correctives works in the equipment, when preventive tasks were performed on them; less dose to perform equipment maintenance; less time to perform equipment maintenance; shorter outages, with less dose; less number of personnel accidents; etc

  17. Researching quality of life in Argentina

    Directory of Open Access Journals (Sweden)

    Graciela Tonón

    2015-09-01

    Full Text Available The study of quality of life considers at the same time objective and subjective circumstances of people life. In 1995 was created the International Society for Quality of Life Studies (ISQOLS whose purposes are to promote and encourage research in the field of quality-of-life studies and provide an organization through which all academic and professional researchers interested in QOL studies may coordinate their efforts to advance the field of QOL studies within various disciplines. In the case of Argentina since 2004, the Facultad de Ciencias Sociales, Universidad Nacional de Lomas de Zamora has organized the Research Program in Quality of life to develop different kind of projects about quality of life in different fields, trying to be considered by national institutions that decide public policies. 

  18. Health in Argentina under the Military Junta.

    Science.gov (United States)

    Bermann, S; Escudero, J C

    1978-01-01

    The socioeconomic policies of Argentina's Military Junta, in power since March 1976, have led to a sharp impoverishment of the vast majority of the population. In the health sector, facilities which previously were public are being transferred to the private sector, and public hospitals formerly providing free services to the population now charge patients for the care received. As a necessary counterpart to these unpopular measures, a regime of terror has been waged against members of the health team--both those politically active and those considered potentially subversive, particularly the psychiatrists and workers in community health. Differences between the Argentinian situation and previous European fascist patterns are noted, and the possibility of use of the "Argentinian model" in other capitalist countries in crisis is discussed.

  19. Virtual Archaeology in an argentina colonial estancia

    Directory of Open Access Journals (Sweden)

    Florencia Vázquez

    2014-05-01

    Full Text Available This is a first approach to the application of virtual reconstruction techniques of a colonial house. In Argentina it is still uncommon to perform 3D modeling of archaeological sites and especially in historical archeology. As a first step, we used the Google SketchUp to model the country house located on the banks of the Río de la Plata (Buenos Aires. It has historical significance because it belonged to a Spanish councilman, housed hundreds of slaves and was the place where stayed the troops that carried out the Second British Invasion of Buenos Aires. In this case, the 3D modeling was useful for evaluating the future excavationa and activities of preservation of cultural heritage.

  20. MEMORIA Y CULTURA OBRERA EN ARGENTINA

    Directory of Open Access Journals (Sweden)

    Universidad de Buenos

    2010-06-01

    Full Text Available Esta ponencia tiene como objetivo rastrear la existencia de una cultura obrera izquierdista en el interior de la Argentina ha partir de testimonios de obreros, intelectuales y de militantes de izquierda. De esta manera, la Historia Oral como metodología de investigación nos proporcionará una herramienta indispensable para echar luz sobre este tema que ha sido hasta el momento descuidado. Para tal efecto, nos centraremos en ciudades del interior la provincia de Córdoba en la década de1930. A partir de los testimonios recogidos se analizarán los problemas de la memoria de sus protagonistas y su resignificación desde el presente, las nociones que tienen los protagonistas sobre la política, la cultura y la militancia sobre el período estudiado.

  1. Nuclear fuel supply view in Argentina

    International Nuclear Information System (INIS)

    Cirimello, R.O.

    1997-01-01

    The Argentine Atomic Energy Commission promoted and participated in a unique achievement in the R and D system in Argentina: the integration of science technology and production based on a central core of knowledge for the control and management of the nuclear fuel cycle technology. CONUAR SA, as a fuel manufacturer, FAE SA, the manufacturer of Zircaloy tubes, CNEA and now DIOXITEC SA producer of Uranium Dioxide, have been supply, in the last ten years, the amount of products required for about 1300 Tn of equivalent U content in fuels. The most promising changes for the fuel cycle economy is the Slight Enriched Uranium project which begun in Atucha I reactor. In 1997 seventy five fuel assemblies, equivalent to 900 Candu fuel bundles, will complete its irradiation. (author)

  2. OSMUNDACEAE EN ARGENTINA, PARAGUAY Y URUGUAY

    Directory of Open Access Journals (Sweden)

    Marcelo D. Arana

    2015-01-01

    Full Text Available En este estudio se actualiza la taxonomía y distribución de las Osmundaceae, familia de helechos que habitan bosques y humedales subtropicales de la Argentina, Paraguay y Uruguay. Actualmente la familia comprende cuatro géneros, dos de ellos, con una especie cada uno, estan presentes en la región estudiada. Se acepta Osmunda spectabilis como una especie válida, diferente de O. regalis , la que no se encuentra presente en el área de estudio. Se reconoce a nivel de género a Osmundastrum con una única especie O. cinnamomeum var. cinnamomeum . Se incluyen una clave para los géneros, descripciones, la sinonimia relevante para América del Sur, distribuciones e ilustraciones de las especies. Se lectotipifica a Osmunda imbricata, Osmunda palustris y Osmunda spectabilis var. brasiliensis .

  3. MEDIOS, PROTESTA Y EXPERIENCIA EN ARGENTINA

    Directory of Open Access Journals (Sweden)

    María Graciela Rodríguez

    2004-01-01

    Full Text Available El objetivo de este artículo es dar a conocer algunas hipótesis acerca de los modos como se construyen los relatos sobre las protestas populares en Argentina. Para ello expongo los resultados de una etapa de la investigación en la cual se han confrontado el análisis discursivo de textos de medios de comunicación dedicados a la protesta con un corpus de entrevistas a los protagonistas de estas acciones. Los resultados de dicha confrontación muestran la existencia de dos formas distintas de operar sobre el devenir histórico relacionadas no sólo con la distintiva puntuación temporal de la secuencia de los hechos, sino también con los procesos de enmarcado valorativo y su colocación en una serie histórica.

  4. Adequacy features of Nucleoelectrica Argentina Safety Management

    International Nuclear Information System (INIS)

    Rapoport, H.

    1997-01-01

    The Argentine Nuclear Power Plants (NPP) ATUCHA I (357 Mw, SIEMENS) and EMBALSE (648 Mw, CANDU), both of PHWR type, were owned and operated until August 94 by the Comision Nacional de Energia Atomica (CNEA). Until that date, CNEA, the national agency for nuclear R and D, concentrated three activities or roles: Research, Nuclear Regulations and NPP Operation. Since August 1994 NPP's are owned and operated by a state electrical company (Nucleoelectrica Argentina S.A.) the nuclear utility supplying 15% of the national electrical generation demand. NASA is going to be privatized according to a recent national law regulating nuclear activities. The transition from a research agency to a commercial company requires the introduction of changes in the management of activities. Mention of these changes is limited to those relating to Safety

  5. The fourth nuclear power plant in Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Nogarin, Mauro

    2017-01-15

    Since 2006 the nuclear sector in Argentina has aimed at recovering and strengthening its capabilities and facilities. Part of the challenge posed by this revival has been to also accompany the development of activities with a higher level of responsibility for safety and the environment. Among the strategic decisions taken in recent years, one main highlight is the construction of the nuclear power plant CAREM25 entirely with Argentine technology and design under the responsibility of the National Atomic Energy Commission. On February 4, 2015, the Ministry of Federal Planning and the National Energy Administration (NEA) signed the agreement for cooperation and construction of pressurized water reactor (PWR) with ACP-1000 technology, developed in the Peoples Republic of China.

  6. About the Triple A. Argentina 1973 - 1976

    OpenAIRE

    Rostica, Julieta

    2011-01-01

    El 25 de mayo de 1973 el peronismo volvió a gobernar la Argentina tras aproximadamente dos décadas de proscripción y persecución política. Tras su establecimiento, ciertos crímenes comenzaron a ser firmados con “AAA”. La Triple A tuvo la particularidad de desaparecer con el golpe de Estado del 24 de marzo de 1976. ¿Por qué esta organización sólo pudo existir en una democracia erigida en medio de dos dictaduras militares? ¿Por qué existió durante el tan anhelado gobierno peronista? El artículo...

  7. Mirror Coronograph for Argentina (MICA). Primera Luz

    Science.gov (United States)

    Stenborg, G.; Epple, A.; Schwenn, R.; Francile, C.; Rovira, M.

    En Julio de 1997 se terminó con la primera parte de la instalación del ``Coronógrafo de Espejo para la Argentina'' en la estación de altura Carlos U. Cesco (El Leoncito), gracias al esfuerzo de la gente del Max Planck Institut für Aeronomie (Alemania), del OAFA y del IAFE. Dicho coronógrafo forma parte de un programa de ciencia bilateral entre Alemania y Argentina. El propósito del mismo, en conjunción con otros telescopios solares y terrestres, es contribuir a un mejor entendimiento de cuestiones fundamentales de la física solar. Para ello, ya está observando la corona de emisión en el verde (Fe XIV), rojo (Fe X) y Hα entre 1.05 y 2 radios solares aproximadamente. El diseño del instrumento, el cual fuera ya presentado en esta misma reunión en La Plata en 1996, es esencialmente similar al del telescopio LASCO-C1 a bordo del Solar Heliospheric Observatory (SOHO). La adquisición de datos se realiza con un CCD de 1280x1024 pixels, codificando en 12 bits, pudiendo ser el mismo operado en forma remota. En esta reunión presentaremos algunas de las observaciones realizadas durante la puesta a punto del instrumento en el período julio-setiembre de 1997. Asimismo expondremos cómo y por qué sus resultados complementarán a los de su par en el espacio.

  8. Argentina: Camino del desendeudamiento. 1991-2011

    Directory of Open Access Journals (Sweden)

    Pablo Nemiña

    2012-05-01

    Full Text Available El presente artículo analiza las transformaciones de la política financiera en la Argentina durante el período 1991-2011. Para ello, se estudian las principales acciones del Estado orientadas a enfrentar la problemática de la deuda pública y el financiamiento, así como las relaciones establecidas con el sector financiero y el FMI. La evolución de la política financiera argentina resalta uno de los contrapuntos más sobresalientes entre el período de la convertibilidad vigente hasta 2001 y la etapa posterior. El régimen de convertibilidad implicó el sostenimiento de una moneda nacional sobrevaluada, la cual determinó el progresivo incremento de la deuda pública y alentó el proceso de financiarización de la economía. En cambio, el régimen de la posconvertibilidad, apoyado en el mantenimiento de un tipo de cambio competitivo junto al superávit fiscal y comercial, ha contribuido a promover la actividad productiva por sobre la financiera. Esto, junto a la reestructuración de la deuda, ha permitido sostener un proceso de reducción gradual del endeudamiento público en términos relativos, liberando recursos para fomentar el mercado interno. Consecuentemente, con posterioridad a 2002 se observa una erosión de la capacidad de condicionamiento estructural sobre la dinámica del crecimiento de los acreedores, el FMI, y el sector financiero en general, en simultáneo con la obtención de mayores grados de autonomía financiera por parte del Gobierno Nacional. Finalmente, se analizan los desafíos que impone la crisis internacional a la continuación de este sendero.

  9. 222Rn Measurements in Dwellings of Argentina

    International Nuclear Information System (INIS)

    Gnoni, G.; Canoba, A.; Czerniczyniec, M.

    2011-01-01

    Radon gas ( 222 Rn) is responsible of about fifty per cent of the world population dose due to natural sources, being the most important pathway the inhalation of radon progeny, specially indoors. Radon concentration has been measured in dwellings at different locations in Argentina. The places selected to be evaluated are representative of the different geologic zones of the country. Near 3000 dwellings have been analyzed since 1983 up today. The measuring methods used in this case were track etched detectors, electrets and detectors based on activated charcoal adsorption. Two different methods with track etched detectors were used: a simple one, which determines only the average radon concentration, and a second one that measures both radon concentration and the equilibrium factor (F) between radon and its daughters. The last one is a method that uses two Makrofol passive track detectors in the same device. The average radon concentration value obtained from all the dwellings evaluated was 44.2 Bq.m-3. The annual effective dose calculated from this average concentration, using a dosimetric factor of 25 μSv.a- 1. (Bq.m -3 ) -1 , which assumes an equilibrium factor of 0.4, was 1.11 mSv. The average value obtained from the 222 dwellings evaluated by the second method was 49.3 Bq.m -3 and 0,37 the equilibrium factor, resulting the annual effective dose estimated 1,44 mSv. The measured equilibrium factor of 0,37 allows us to verify the assumed equilibrium factor of 0,4. Finally, radon levels in dwellings of Argentina are within the acceptable values for population, not being necessary to implement remedial actions, except in isolate cases that are still under study. (authors)

  10. Decoding a protracted zircon geochronological record in ultrahigh temperature granulite, and persistence of partial melting in the crust, Rogaland, Norway

    Science.gov (United States)

    Laurent, Antonin T.; Bingen, Bernard; Duchene, Stephanie; Whitehouse, Martin J.; Seydoux-Guillaume, Anne-magali; Bosse, Valerie

    2018-04-01

    This contribution evaluates the relation between protracted zircon geochronological signal and protracted crustal melting in the course of polyphase high to ultrahigh temperature (UHT; T > 900 °C) granulite facies metamorphism. New U-Pb, oxygen isotope, trace element, ion imaging and cathodoluminescence (CL) imaging data in zircon are reported from five samples from Rogaland, South Norway. The data reveal that the spread of apparent age captured by zircon, between 1040 and 930 Ma, results both from open-system growth and closed-system post-crystallization disturbance. Post-crystallization disturbance is evidenced by inverse age zoning induced by solid-state recrystallization of metamict cores that received an alpha dose above 35 × 1017 α g-1. Zircon neocrystallization is documented by CL-dark domains displaying O isotope open-system behaviour. In UHT samples, O isotopic ratios are homogenous (δ18O = 8.91 ± 0.08‰), pointing to high-temperature diffusion. Scanning ion imaging of these CL-dark domains did not reveal unsupported radiogenic Pb. The continuous geochronological signal retrieved from the CL-dark zircon in UHT samples is similar to that of monazite for the two recognized metamorphic phases (M1: 1040-990 Ma; M2: 940-930 Ma). A specific zircon-forming event is identified in the orthopyroxene and UHT zone with a probability peak at ca. 975 Ma, lasting until ca. 955 Ma. Coupling U-Pb geochronology and Ti-in-zircon thermometry provides firm evidence of protracted melting lasting up to 110 My (1040-930 Ma) in the UHT zone, 85 My (ca. 1040-955 Ma) in the orthopyroxene zone and some 40 My (ca. 1040-1000 Ma) in the regional basement. These results demonstrate the persistence of melt over long timescales in the crust, punctuated by two UHT incursions.

  11. Evaluating the utility of hydrocarbons for Re-Os geochronology : establishing the timing of processes in petroleum ore systems

    Energy Technology Data Exchange (ETDEWEB)

    Selby, D.; Creaser, R.A. [Alberta Univ., Edmonton, AB (Canada). Dept. of Earth and Atmospheric Sciences

    2005-07-01

    Oil from 6 Alberta oil sands deposits were analyzed with a rhenium-osmium (Re-Os) isotope chronometer, an emerging tool for determining valuable age information on the timing of petroleum generation and migration. The tool uses molybdenite and other sulphide minerals to establish the timing and duration of mineralization. However, establishing the timing events of petroleum systems can be problematic because viable sulphides for the Re-Os chronometer are often not available. Therefore, the known presence of Re and Os associated with organic matter in black shale, a common source of hydrocarbons, may suggest that bitumen and petroleum common to petroleum systems may be utilised for Re-Os geochronology. This study evaluated the potential of the Re-Os isotopic system for geochronology and as an isotopic tracer for hydrocarbon systems. The evaluation was based on Re-Os isotopic analyses of bitumen and oil sands. Hydrocarbons formed from migrated oil in both Alberta oil sand deposits and a Paleozoic Mississippi Valley-type lead-zinc deposit contain significant Re and Os contents with high {sup 187}Re/{sup 188}Os and radiogenic {sup 187}Os/{sup 188}Os ratios suitable for geochronology. The oil from the 6 Alberta oil sand deposits yields Re-Os analyses with very high Re/{sup 188}Os ratios, and radiogenic Os isotopic compositions. Regression of the Re-Os data yields a date of 116 {+-} 27 Ma. This date plausibly represents the period of in situ radiogenic growth of {sup 187}Os following hydrocarbon migration and reservoir filling. Therefore, directly dating these processes, and this formation age corresponds with recent burial history models for parts of the Western Canada Sedimentary Basin. The very high initial {sup 187}Os/{sup 188}Os for this regression requires rocks much older than Cretaceous for the hydrocarbon source.

  12. Geochronology of the Thompson Creek Mo Deposit: Evidence for the Formation of Arc-related Mo Deposits

    Science.gov (United States)

    Lawrence, C. D.; Coleman, D. S.; Stein, H. J.

    2016-12-01

    The Thompson Creek Mo deposit in central ID, has been categorized as an arc-related Mo deposit due to the location, grade of Mo, and relative lack of enrichments in F, Rb, and Nb, compared to the Climax-type Mo deposits. Geochronology from this arc-related deposit provides an opportunity to compare and contrast magmatism, and mineralization to that in Climax-type deposits. Distinct pulses of magmatism were required to form the Thompson Creek Mo deposit, which is consistent with recent geochronology from Climax-type deposits. Molybdenite Re-Os geochronology from five veins requires at least three pulses of magmatism and mineralization between 89.39 +/- 0.37 and 88.47 +/- 0.16 Ma. Zircon U-Pb ages from these mineralized samples overlap with molybdenite mineralization, but show a much wider range (91.01 +/- 0.37 to 87.27 +/- 0.69). Previous work from Climax-type Mo deposits suggest a correlation between a super eruption, and the subsequent rapid (<1 Ma) onset, and completion of Mo mineralizing intrusions. The longer life (3-4 Ma) for the Thompson Creek Mo deposit suggests that the mineralizing intrusions for arc-related Mo deposits may not need to have as high [Mo] as the Climax-type deposits. This study also finds a shift in the source of magmatism from the pre- to syn-mineralizing intrusions. Zircons from pre-mineralizing intrusions have much higher (15-60 pg) concentrations of radiogenic Pb than zircons from mineralized intrusions, which all have less than 15 pg, though whole rock [U] are similar.

  13. The multiple applications of the nuclear techniques in Argentina; Las multiples aplicaciones de la tecnologia nuclear en Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Manzini, Alberto C [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Programa de Radioisotopos y Aplicaciones

    2001-07-01

    A review is given of the use of nuclear technology in Argentina, especially in the field of the production of radioisotopes and radiopharmaceuticals, nuclear medicine, and industrial applications. The applications of ionizing radiation are also reviewed.

  14. Geochemistry and geochronology of the Archean and palaeo-Proterozoic formations of southern Cameroon (Ntem group, Congo craton)

    International Nuclear Information System (INIS)

    Rchameni, R.

    1997-01-01

    The aim of this work is to understand the crustal evolution of the NW margin of the Congo craton using structural, petrography, isotopic, geochemical and geochronological studies of the Archean and palaeo-Proterozoic formations of the Ntem group of southern Cameroon. The synthesis of these studies allows to propose a diapir-type gravity model linked with the genesis of granitoids to explain the geodynamical evolution of this part of the craton during the Archean. A convergence model with the collision of the Congo and Sao-Francisco cratons and with crust thickening followed by a relaxation phase is proposed for the palaeo-Proterozoic. (J.S.)

  15. The lower Mesozoic record of detrital zircon U-Pb geochronology of Sonora, Mexico, and its paleogeographic implications

    OpenAIRE

    González-León, Carlos M.; Valencia, Víctor A.; Lawton, Timothy F.; Amato, Jeffrey M.; Gehrels, George E.; Leggett, William J.; Montijo-Contreras, Óscar; Fernández, Miguel A.

    2009-01-01

    Detrital zircon U-Pb geochronology from each of the formations of the Triassic-Lower Jurassic Barranca and El Antimonio groups of central and northwestern Sonora and from the Lower Jurassic Basomari and Middle Jurassic Lily formations of northern Sonora indicate they contain distinctive zircon populations. A Proterozoic population has peak ages near 1.8, 1.7, 1.6, 1.4, and 1.1 Ga. A population of Permo-Triassic grains with important peak ages near 269, 254, 245, 234 and 227 Ma. A third popula...

  16. 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

  17. High-Flux Neutron Generator Facility for Geochronology and Nuclear Physics Research

    Science.gov (United States)

    Waltz, Cory; HFNG Collaboration

    2015-04-01

    A facility based on a next-generation, high-flux D-D neutron generator (HFNG) is being commissioned at UC Berkeley. The generator is designed to produce monoenergetic 2.45 MeV neutrons at outputs exceeding 1011 n/s. The HFNG is designed around two RF-driven multi-cusp ion sources that straddle a titanium-coated copper target. D + ions, accelerated up to 150 keV from the ion sources, self-load the target and drive neutron generation through the d(d,n)3 He fusion reaction. A well-integrated cooling system is capable of handling beam power reaching 120 kW impinging on the target. The unique design of the HFNG target permits experimental samples to be placed inside the target volume, allowing the samples to receive the highest neutron flux (1011 cm-2 s-1) possible from the generator. In addition, external beams of neutrons will be available simultaneously, ranging from thermal to 2.45 MeV. Achieving the highest neutron yields required carefully designed schemes to mitigate back-streaming of high energy electrons liberated from the cathode target by deuteron bombardment. The proposed science program is focused on pioneering advances in the 40 Ar/39 Ar dating technique for geochronology, new nuclear data measurements, basic nuclear science, and education. An end goal is to become a user facility for researchers. This work is supported by NSF Grant No. EAR-0960138, U.S. DOE LBNL Contract No. DE-AC02-05CH11231, U.S. DOE LLNL Contract No. DE-AC52-07NA27344, and UC Office of the President Award 12-LR-238745.

  18. Geochronology and Fluid-Rock Interaction Associated with the Nopal I Uranium Deposit, Pena Blanca, Mexico

    International Nuclear Information System (INIS)

    Fayek, M.; Goodell, P.; Ren, M.; Simmons, A.

    2005-01-01

    The Nopal I uranium (U) deposit, Pena Blanca District, Mexico, largely consists of secondary U 6+ minerals, which occur within a breccia pipe mainly hosted by the 44 Ma Nopal and Colorados volcanic formations. These two units overly the Pozos conglomerate formation and Cretaceous limestone. Three new vertical diamond drill holes (DDHs) were recently drilled at Nopal I. DDH-PB1 with continuous core was drilled through the Nopal I deposit and two additional DDHs were drilled ∼50 m on either side of the cored hole. These DDHs terminate 20 m below the current water table, thus allowing the detection of possible gradients in radionuclide contents resulting from transport from the overlying uranium deposit. Primary uraninite within the main ore body is rare and fine-grained (∼50 micrometers), thus making geochronology of the Nopal I deposit very difficult. Uranium, lead and oxygen isotopes can be used to study fluid-uraninite interaction, provided that the analyses are obtained on the micro-scale. Secondary ionization mass spectrometry (SIMS) permits in situ measurement of isotopic ratios with a spatial resolution on the scale of a few (micro)m. Preliminary U-Pb results show that uraninite from the main ore body gives an age of 32 ± 8 Ma, whereas uraninite from the uraniferous Pozos conglomerate that lies nearly 100 m below the main ore body and 25 meters above the water table, gives a U-Pb age that is 18 O = -10.8(per t housand), whereas the uraninite within the Pozos conglomerate has a (delta) 18 O = +1.5(per t housand). If it is assumed that both uraninites precipitated from meteoric water ((delta) 18 O = -7(per t housand)), then calculated precipitation temperatures are 55 C for the uraninite from the ore body and 20 C for uraninite hosted by the Pozos conglomerate. These temperatures are consistent with previous studies that calculated precipitation temperatures for clay minerals associated with uraninite

  19. The Middlesex Fells Volcanic Complex: A Revised Tectonic Model based on Geochronology, Geochemistry, and Field Data

    Science.gov (United States)

    Hampton, R.

    2017-12-01

    The Boston Bay area is composed of several terranes originating on the paleocontinent of Avalonia, an arc terrane that accreted onto the continent of Laurentia during the Devonian. Included in these terranes is the Middlesex Fells Volcanic Complex, a bimodal complex composed of both intrusive and extrusive igneous rocks. Initial studies suggested that this volcanic complex formed during a rift event as the Avalonian continent separated from its parent continent 700-900 Ma. New geochemical and geochronological data and field relationships observed in this study establishes a new tectonic model. U-Pb laser ablation zircon data on four samples from different units within the complex reveal that the complex erupted 600 Ma. ICP-MS geochemical analysis of the metabasalt member of the complex yield a trace element signature enriched in Rb, Pb, and Sr and depleted in Th, indicating a subduction component to the melt and interpreted as an eruption into a back-arc basin. The felsic units similarly have an arc related signature when plotted on trace element spider diagrams and tectonic discrimination diagrams. Combined with the field relationships, including an erosional unconformity, stratigraphic and intrusional relationships and large faults from episodic extension events, this data suggests that the Middlesex Fells Volcanic Complex was erupted as part of the arc-sequence of Avalonia and as part of the formation of a back-arc basin well after Avalonia separated from its parent continent. This model presents a significantly younger eruption scenario for the Middlesex Fells Volcanics than previously hypothesized and may be used to study and compare to other volcanics from Avalon terranes in localities such as Newfoundland and the greater Boston area.

  20. Quaternary Geochronology, Paleontology, and Archaeology of the Upper San Pedro River Valley, Sonora, Mexico

    Science.gov (United States)

    Gaines, E. P.

    2013-12-01

    This poster presents the results of multi-disciplinary investigations of the preservation and extent of Quaternary fossil-bearing strata in the San Pedro River Valley in Sonora, Mexico. Geologic deposits in the portions of the San Pedro Valley in southern Arizona contain one of the best late Cenozoic fossil records known in North America and the best record of early humans and extinct mammals on the continent. The basin in the U.S. is one of the type locations for the Blancan Land Mammal Age. Hemiphilian and Irvingtonian fossils are common. Rancholabrean remains are widespread. Strata in the valley adjacent to the international border with Mexico have yielded the densest concentration of archaeological mammoth-kill sites known in the western hemisphere. Despite more than 60 years of research in the U.S., however, and the fact that over one third of the San Pedro River lies south of the international boundary, little has been known about the late Cenozoic geology of the valley in Mexico. The study reported here utilized extensive field survey, archaeological documentation, paleontological excavations, stratigraphic mapping and alluvial geochronology to determine the nature and extent of Quaternary fossil-bearing deposits in the portions of the San Pedro Valley in Sonora, Mexico. The results demonstrate that the Plio-Pleistocene fossil -bearing formations known from the valley in Arizona extend into the uppermost reaches of the valley in Mexico. Several new fossil sites were discovered that yielded the remains of Camelids, Equus, Mammuthus, and other Proboscidean species. Late Pleistocene archaeological remains were found on the surface of the surrounding uplands. AMS radiocarbon dating demonstrates the widespread preservation of middle- to late- Holocene deposits. However, the late Pleistocene deposits that contain the archaeological mammoth-kill sites in Arizona are absent in the valley in Mexico, and are now known to be restricted to relatively small portions of

  1. Stratigraphical sequence and geochronology of the volcanic rock series in caifang basin, south jiangxi

    International Nuclear Information System (INIS)

    Xu Xunsheng; Wu Jianhua

    2010-01-01

    The late Mesozoic volcanic rocks in Jiangxi constitute two volcanic belts: the northern is Xiajiang-Guangfeng volcanic belt, the volcanic rocks series belong to one volcano cycle and named Wuyi group which is subdivided into three formations (Shuangfengling formation, Ehuling formation and Shixi formation); the southern is Sannan-Xunwu volcanic belt, the volcanic rocks series in Caifang basin which locates on Sannan-Xunwu volcanic belt also belong to only one volcano cycle. It can be subdivided into two lithology and lithofacies units (upper and lower): the lower unit consists of sedimentary rocks and associated with a subordinate amount of volcanic rocks, it belongs to erupt-deposit facies which is the product of early volcanic stage; the upper unit is mostly composed of volcanic rocks, it belongs to erupt facies that is the volcanic eruption product. SHRIMP zircon U-Pb age of rhyolite? which locates at the top of the upper unit is 130.79 ± 0.73) Ma. According to the new International Stratigraphic Chart, the boundary of Jurassic and Cretaceous is (145.4 ± 4.0) Ma, so the age shows that the geologic period of Caifang volcanic rocks series is early Early Cretaceous epoch. On the basis of lithological correlation, lithofacies and stratigraphic horizon analysis, the volcanic rock series in Caifang basin fall under Wuyi group, and the lower unit could be incorporated into Shuangfengling formation, the upper unit could be incorporated into Ehuling formation. The subdivision of sequence and the determination of geochronology of the volcanic rock series in Caifang basin provide some references for the study of the late Mesozoic volcanic rocks series of the Sannan-Xunwu volcanic belt. (authors)

  2. Pangea: Geochronological correlation of successive environmental and strati-tectonic phases in Europe and Australia

    Science.gov (United States)

    Veevers, J. J.

    2013-12-01

    A robust geochronology based on U-Pb zircon ages in Australia (n = 158) and Europe (n = 376) provides a rigorous test of (1) the model of a climatic-tectonic cycle of a single continent (Pangea) and ocean (Panthalassa) with an icehouse climate alternating with many continents and oceans with a greenhouse climate, and (2) the idea of coeval (320 to 300 Ma) right-lateral shear events in Eastern Australia and Europe followed by earliest Permian (~ 300 Ma) extension. During Pangean assembly, stress from the oblique collision of Laurussia and Gondwanaland bent the oroclines in Iberia, drove the intense shortening in Central Australia and terminal megakinking in the Lachlan orogen, and possibly drove the bending of oroclines in Eastern Australia. Extension I (~ 300 Ma, Carboniferous/Permian) followed the first outburst of self-induced (monsoonal) heat from the newly assembled Pangea, and generated fresh accommodation space for globally synchronous sedimentary successions, including the glacial base and succeeding coals of the Gondwana facies. Extension was relieved by sags on (isotropic) cratons and rifts on (anisotropic) fold belts with voluminous volcanics. In Europe, the Variscan orogen was cut into right-lateral magmatic rifts and the craton sagged to accumulate magmatic basins; likewise, the convergent margin of Eastern Australia was cut into a long magmatic rift and the cratonic foreland covered by the Gondwana facies. The end-Permian (251 Ma) sea-level drawdown, climate warming, and severe biotic extinction, with no obvious tectonic cause, were responsible for the Early-Middle Triassic coal gap. A second outburst of heat drove Extension II (235 Ma, Carnian, Late Triassic), expressed as rifts and sags that accumulated a second set of coal-bearing strata. At this time of its largest extent, Pangea underwent incipient breakup by rifting of the Atlantic Margins of North America, Morocco, and Western Europe that developed into 190 Ma drifting.

  3. U–Pb geochronology and geochemistry of late Palaeozoic volcanism in Sardinia (southern Variscides

    Directory of Open Access Journals (Sweden)

    L. Gaggero

    2017-11-01

    Full Text Available The latest Carboniferous to lower Permian volcanism of the southern Variscides in Sardinia developed in a regional continental transpressive and subsequent transtensile tectonic regime. Volcanism produced a wide range of intermediate–silicic magmas including medium- to high-K calc-alkaline andesites, dacites, and rhyolites. A thick late Palaeozoic succession is well exposed in the four most representative Sardinian continental basins (Nurra, Perdasdefogu, Escalaplano, and Seui–Seulo, and contains substantial stratigraphic, geochemical, and geochronological evidence of the area's complex geological evolution from the latest Carboniferous to the beginning of the Triassic. Based on major and trace element data and LA-ICP-MS U–Pb zircon dating, it is possible to reconstruct the timing of post-Variscan volcanism. This volcanism records active tectonism between the latest Carboniferous and Permian, and post-dates the unroofing and erosion of nappes in this segment of the southern Variscides. In particular, igneous zircon grains from calc-alkaline silicic volcanic rocks yielded ages between 299 ± 1 and 288 ± 3 Ma, thereby constraining the development of continental strike-slip faulting from south (Escalaplano Basin to north (Nurra Basin. Notably, andesites emplaced in medium-grade metamorphic basement (Mt. Cobingius, Ogliastra show a cluster of older ages at 332 ± 12 Ma. Despite the large uncertainty, this age constrains the onset of igneous activity in the mid-crust. These new radiometric ages constitute: (1 a consistent dataset for different volcanic events; (2 a precise chronostratigraphic constraint which fits well with the biostratigraphic data and (3 insights into the plate reorganization between Laurussia and Gondwana during the late Palaeozoic evolution of the Variscan chain.

  4. The Padre Miguel Ignimbrite Suite, central Honduras: Paleomagnetism, geochronology, and tectonic implications

    Science.gov (United States)

    Garza, Roberto S. Molina; van Hinsbergen, Douwe J. J.; Rogers, Robert D.; Ganerød, Morgan; Dekkers, Mark J.

    2012-10-01

    The Padre Miguel Group in western Honduras is a silicic volcanic sequence that forms part of the Central American Miocene volcanic arc built on the Chortis continental fragment. We report new 40Ar/39Ar data of 16.1 ± 0.2 Ma and 14.42 ± 0.08 Ma for the Padre Miguel Group, and present paleomagnetic data for 36 cooling units (mainly ignimbrites) from localities north and northeast of the capital city of Tegucigalpa. These rocks are characterized by univectorial characteristic magnetization carried mainly by low-Ti titanomagnetites, or two component magnetizations with a minor secondary overprint. Dual polarity magnetizations suggest that it is a primary thermo-remanence and the obtained data scatter can be straightforwardly explained by paleosecular variation. The overall mean of 33 selected sites (14.39°N, 87.14°W) defines a paleomagnetic pole at lat = 80.0°N, lon = 142.9°E (K = 24.5, A95 = 5.2°). The overall mean compared with the North America expected direction indicates statistically insignificant rotation and inclination anomaly (R = - 4.1° ± 6.1° and an F = - 8.6° ± 11.3°). Restoring 255 km of sinistral slip in the Polochic-Motagua fault system, as suggested by Cayman Trough reconstructions since 15 Ma, brings the mid-Miocene arcs of southern Mexico (Oaxaca) and the Central America ignimbrite province into alignment; this is consistent with a derivation of the Chortis Block from southern Mexico. Our paleomagnetic and geochronological studies hence support models that explain the offset of the Miocene ignimbrite belt of Central America by post-Middle Miocene displacement of the Chortis Block relative to North America.

  5. The geochronological data of South-Riograndense shield and its implications on geotectonic order

    International Nuclear Information System (INIS)

    Soliani Junior, E.

    1986-01-01

    Based on 250 new radiometric analyses using K-Ar, Rb-Sr, Pb-Pb and Fission Tracks methods, all of them interpreted with the existing geochronological data, this paper divides the Rio Grande do Sul Shield (Southern Brazil) into geotectonic provinces, as well as presents the ages that seem to be of the major rock generator events. It is suggested that the Brasiliano Cycle (Upper Precambrian) was active during a time interval greater than has been thought and its chronological limits could be extended from 850 to 550 Ma with late and local magmatic episodes reaching the 450 Ma ago. Outcrops of Early Proterozoic or older terranes are rare, being the most areas related to the Late Proterozoic. These areas can be divided into two tectonic entities: (1) the Pelotas Batholit, a multi-intrusive and polyphase granitoid body, in the eastern shield, pointing out ages that range from 850 to 550 Ma and (2) its Marginal Basin in the west represented by supracrustal rocks such as gneisses, mafic-ultramafic and volcano-sedimentary sequences showing a complex structural pattern and green schists to amphibolite metamorphic facies. Their K-Ar and Rb-Sr ages are concentrated between 760 and 640 Ma, though values of 800 may be found. Polyphase granitic suites and their volcanic correspondents, sometimes interbabded with molassoid sediments, are being attributes to the 650 - 450 Ma time interval. Finally, it tries to enclose the Rio Grande do Sul Shield in the regional geologic context (Southern Brazil and Uruguay), which to supposed to have developed in agreement with the Plate Tectonic. (Author) [pt

  6. Indirect dating of deformation: a geochronological study from the Pan African Ajaj shear zone, Saudi Arabia.

    Science.gov (United States)

    Hassan, Mahmoud; Abu-Alam, Tamer; Stüwe, Kurt; Klötzli, Urs

    2013-04-01

    The metamorphic complexes of the Arabian-Nubian Shield were exhumed by different exhumation mechanisms (i.e. in extension or oblique transpression regime) during the Pan African activity of Najd Fault System - the largest pre-Mesozoic shear zone on Earth. The different exhumation mechanisms could be the consequence of (i) orientation of the complexes at slightly different angles with respect to the overall orientation of the principal stresses of the Najd Fault System, (ii) exhumation from different depths, or (iii) change of the stress regime through time. In order to test the third hypothesis, geochronological work will be applied on a representative suite of complexes across the Najd Fault System. In particular we focus on three complexes in the Arabian part of the shield named Qazaz, Hamadat and Wajh. In general, the metamorphic complexes of the Arabian part of the shield exhibit left-lateral transcurrent tectonism along the NW-SE Najd faults and right-lateral movement along conjugate NE-SW striking structures. The whole unit forms an anastomosing network of planar structures that demarcate large fish-shaped bodies of high grade metamorphics. The Hamadat complex is surrounded by a left-lateral greenshist facies WNW-ESE Ajaj shear zone. The complex consists of folds that are strongly pinched to the north and more open to the south marked by a well-developed parallel stretching sub-horizontal lineation. Granite intrusions along and across the Ajaj shear zone may allow testing the timing of the deformation. Deformed and non-deformed samples of these granites will be examined by age dating to determine the absolute timing of the metamorphism and the deformation for the complex. Some 20 samples are currently being prepared for zircon dating. Whilst no results are available at the time of writing of this abstract, they will be presented at EGU 2013.

  7. Sediments of the Lagoa Olho D'Agua: geochronology and accumulation of trace metals

    International Nuclear Information System (INIS)

    Honorato, Eliane Valentim

    2002-01-01

    An assessment of the environmental impact of anthropic activities in the Lagoa Olho D'Agua, located in Jaboatao dos Guararapes County, Brazil, was carried out by assessing the vertical distribution of some trace metals (Cd, Cr, Fe, Hg, Ni, U, Zn and Zr) in dated sediment samples. Sediment cores were collected from thirteen locations at the northern, central and southern sections of the lagoon. The metal content in the samples was determined by Instrumental Neutron Activation Analysis (INAA). Its organic carbon content was also determined and used to characterize the environment as, either oxic or anoxic environments can bias the trace element content of sediment samples. The influence of the hydrodynamic characteristics in the sedimentation process was also studied. The results obtained for the geochronology of sediments showed a pronounced increase in sedimentation rates in the period of 1970 - 1980 and 1980 - 1990 in the sampling stations ST-09, ST-10, ST-11, ST-12 e ST-13 (ca.480% in the 80's to 90's ) compared to ca. 90% increase observed in other sampling stations. This increase can be associated to the demographic growth of ca. 500% that occurred in Jaboatao dos Guararapes County in the 80's to 90's predominantly along the shoreline. The geochemistry analyses of sediment samples, on the other hand, showed that the severe degradation process the occurred in the lagoon in the last 30 years was caused by the release of pollutants from industrial facilities as well as by the discharge of untreated domestic sewage. These domestic sewage favorable the increase of the concentration of organic material in the lagoon, accentuating the adsorption process of the metals on the sediments, mainly Fe and Zr in the suspense particles. The accentuated increase observed in both Fe and Zr concentrations is compatible with period of built industries basic steel works foundries and painting, indicating the anthropogenic origin these metals. (author)

  8. Carbon and oxygen isotopes in carbonatites from Puna, Jujuy and Salta, Argentina

    International Nuclear Information System (INIS)

    Zappettini, Eduardo O.; Rubiolo, Daniel

    1998-01-01

    δ 13 and δ 18 O data from carbonatites indicate that bodies formed by crystallization of carbonate magma with subsequent formation of metasomatic and hydrothermal carbonatitic veins. The isotopic data are consistent with the available geochemical and petrologic information. (author)

  9. 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

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

    Science.gov (United States)

    Janisch, Astrid; Ntaflos, Theodoros

    2015-04-01

    .7 to 91.6. Cr# in sp extends from 50.4 to 87.9 suggesting that all pre-existing sp has been influenced by melt percolation. A striking feature of these rocks is the presence of intergranular glasses as an effect of melt percolation. The composition of the glasses is phonolitic, trachytic and basanitic. Such compositions correspond to the rock types found in the south of La Palma along the Cumbre Vieja ridge indicating that the xenoliths besides the modal metasomatism have experienced host basalt infiltration. The peculiarity of one sample is haüyne, localized within veins in association with amphibole, olivine and clinopyroxene. Evidently in this sample, the host-basalt infiltrated the mantle xenolith for haüyne is commonly part of basaltic lava. Equilibration temperatures calculated using two-pyroxene-thermometer of Brey and Koehler (1990) are estimated to be in the wide range of 726 to 1105°C at 1.5 GPa pressure, indicating that the studied xenoliths sample various depths of the oceanic lithosphere underneath the Canary Islands. References BREY, G.P. & KOEHLER, T. (1990). Geothermobarometry in four-phase lherzolites II. New thermobarometers, and practical assessment of existing thermobarometers. Journal of Petrology 31, 1353-1378.

  11. 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

  12. CARACTERIZACIÓN Y PROCEDENCIA DE MATERIAS PRIMAS PARA LA PRODUCCIÓN DE ALFARERÍA PREHISPÁNICA EN LA QUEBRADA DE HUMAHUACA (PROVINCIA DE JUJUY, REPÚBLICA ARGENTINA: FRX, ICP Y PETROGRAFÍA DE PASTAS (Characterization and Provenance of Raw Materials for the Production of Prehispanic Pottery in Quebrada de Humahuaca (Jujuy Province, Argentina: XRF, ICP and Ceramic Petrography

    Directory of Open Access Journals (Sweden)

    Nicolás E. Larcher

    2016-03-01

    Full Text Available Se presenta un avance en la investigación arqueométrica de la alfarería prehispánica de la Quebrada de Humahuaca, territorio ubicado en el extremo noroeste de Argentina. Se analizaron 72 muestras de cerámicas y arcillas por FRX e ICP en tres laboratorios distintos. La integración de los datos y su procesamiento estadístico permitió identificar 4 grupos con características químicas definidas. La petrografía de pastas aportó información extra que ayudó a corroborar la congruencia de los agrupamientos obtenidos. Los resultados permitieron relacionar arcillas con cerámicas, diferenciar químicamente las arcillas y cerámicas de dos sectores de la Quebrada de Humahuaca estudiados e identificar posibles evidencias de interacción. ENGLISH: This article presents a new archaeometric investigation of prehispanic pottery from Quebrada de Humahuaca, a valley in the northwesternmost region of Argentina. We assayed 72 samples from pottery and clays using X-RF and ICP in three different laboratories. Data integration and statistical processing allowed us to identify 4 groups with defined chemical signatures. Ceramic petrology provided additional information that helped us to corroborate the coherence of the clustering. The results enabled us to correlate clays with pottery, to establish chemical differences between the clays and pottery of two areas of Quebrada de Humahuaca that have been investigated archaeologically, and to identify possible evidence of social interaction.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. A Argentina depois da conversibilidade: um caso de novo-desenvolvimentismo?

    Directory of Open Access Journals (Sweden)

    André Moreira Cunha

    2009-03-01

    Full Text Available This paper analyses the economic recovery in post-Convertibility Argentina. We try to identify if there are evidences to support the suggestion that Argentina could be an example of the so-called "new developmentalism".

  2. The culture of milk in Argentina

    Directory of Open Access Journals (Sweden)

    Patricia Aguirre

    2003-09-01

    Full Text Available This paper analyses the culture of milk and it includes both the micro social aspects of household consumption and the economic macro aspects related to milk production and their market and the welfare distribution in public policies against poverty. The hypothesis is that in Argentina there is a real culture of milk, which gives meaning to consumption, and marks the different income groups within society, as well as their gender and age. But since approximately 20 years ago, in accordance with the restructuring of the dairy industrial complex, that culture of milk has been changing, and its most outstanding features are the following: abandonment of milk as the emblematic food for children and its extension to the adult “formal” consumption; milk is no longer the knowledge of women and becomes the knowledge of experts; increase in milk consumption (dairy products in general as food gets feminine, infantile, medicated, globalised and segmented.Este artículo sobre la cultura de la leche analiza los aspectos microsociales del consumo en el hogar y los aspectos macro de la economía que hacen a la industria lactea y al mercado junto a la distribución asistencial del estado en los programas contra la pobreza. La hipótesis es que en Argentina existe una verdadera cultura de la leche, que da sentido al consumo, marcando con el alimento los diferentes sectores de ingreso de la sociedad, los géneros y las edades. Pero desde hace aproximadamente 20 años, en consonancia con la reconversión del complejo industrial lácteo, esta cultura de la leche esta cambiando, se describen sus aspectos mas salientes tales como : el abandono de la leche como alimento emblemático de los niños y su extensión al consumo “formal” adulto ; deja de ser un alimento rutinario cuyo saber usar residía en las mujeres y su uso pase a ser cosa de especialistas ; a medida se feminiza, infantiliza, medicaliza, globaliza y segmenta la alimentación en general

  3. Geology and Re-Os molybdenite geochronology of the Kurišková U-Mo deposit (Western Carpathians, Slovakia)

    Czech Academy of Sciences Publication Activity Database

    Kohút, M.; Trubač, J.; Novotný, L.; Ackerman, Lukáš; Demko, R.; Bartalský, B.; Erban, V.

    2013-01-01

    Roč. 58, č. 3 (2013), s. 271-282 ISSN 1802-6222 R&D Projects: GA ČR GA13-15390S Institutional support: RVO:67985831 Keywords : U–Mo ore deposit * Re–Os * molybdenite geochronology * genetic model * Gemeric Unit * Western Carpathians Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.744, year: 2013

  4. Depositional history of a condensed shallow marine reservoir succession: stratigraphy and detrital zircon geochronology of the Jurassic Sto Formation, Barents Sea

    Czech Academy of Sciences Publication Activity Database

    Klausen, T. G.; Müller, R.; Sláma, Jiří; Olaussen, S.; Rismyhr, B.; Helland-Hansen, W.

    2018-01-01

    Roč. 175, č. 1 (2018), s. 130-145 ISSN 0016-7649 Institutional support: RVO:67985831 Keywords : binary alloys * deposition * erosion * geochronology * lead * lead alloys * sea level * silicate minerals * uranium alloys * zircon Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 3.037, year: 2016

  5. Cooperation on Water management issues, Argentina : Project in the framework of Bilateral Cooperation between Argentina and the Netherlands : Case studies on water management issues in Argentina

    NARCIS (Netherlands)

    Querner, E.P.; Morabito, J.A.; Rebori, G.

    2007-01-01

    In Argentina parts of the country have problems encountered from too much water or suffer serious water shortages. The Humid Pampas encounter an increased rainfall since the 1970’s. In Mendoza Province water resources are limited and all the water from the rivers is used for agriculture, drinking

  6. 76 FR 80870 - Notice of Determination of Pest-Free Areas in Mendoza Province, Argentina

    Science.gov (United States)

    2011-12-27

    ... ;D=APHIS-2010-0032. The first commenter acknowledged Argentina's history of successful Medfly control...] Notice of Determination of Pest-Free Areas in Mendoza Province, Argentina AGENCY: Animal and Plant Health... Southern and Central Oases in the southern half of Mendoza Province in Argentina as pest-free areas for...

  7. 76 FR 51934 - Determination of Pest-Free Areas in Mendoza Province, Argentina; Request for Comments

    Science.gov (United States)

    2011-08-19

    ... acknowledged Argentina's history of successful Medfly control efforts, but stated that APHIS should not relax...] Determination of Pest-Free Areas in Mendoza Province, Argentina; Request for Comments AGENCY: Animal and Plant... received a request from the Government of Argentina to recognize additional areas as pest- free areas for...

  8. Economy-wide impacts of biofuels in Argentina

    International Nuclear Information System (INIS)

    Timilsina, Govinda R.; Chisari, Omar O.; Romero, Carlos A.

    2013-01-01

    Argentina is one of the world's largest biodiesel producers and the largest exporter, using soybeans as feedstock. Using a computable general equilibrium model that explicitly represents the biofuel industry, this study carries out several simulations on two sets of issues: (i) international markets for biofuel and feedstock, such as an increase in prices of soybean, soybean oil, and biodiesel, and (ii) domestic policies related to biofuels, such as an introduction of biofuel mandates. Both sets of issues can have important consequences to the Argentinean economy. The simulations indicate that increases in international prices of biofuels and feedstocks would increase Argentina's gross domestic product and social welfare. Increases in international prices of ethanol and corn also can benefit Argentina, but to a lesser extent. The domestic mandates for biofuels, however, would cause small losses in economic output and social welfare because they divert part of biodiesel and feedstock from exports to lower-return domestic consumption. An increase in the export tax on either feedstock or biodiesel also would lead to a reduction in gross domestic product and social welfare, although government revenue would rise. - Highlights: ► Argentina is one of the largest biodiesel producer and exporter using soybeans. ► Economy-wide impacts are assessed using a CGE model for Argentina. ► Policies simulated are feedstock and biodiesel price change, and domestic mandates. ► Increases in international prices of biofuels and feedstock benefit the country. ► Domestic mandates for biofuels cause small losses in economic output

  9. Horizontalidad, autogestión y protagonismo en Argentina

    Directory of Open Access Journals (Sweden)

    Marina Sitrin

    2010-02-01

    Full Text Available Este artículo trata los movimientos sociales autónomos que surgieron después de la crisis económica y la posterior rebelión popular en Argentina en diciembre de 2001. Los movimientos autónomos en la Argentina, como tantos movimientos en el mundo de hoy, son movimientos basados en la creación de nuevas relaciones sociales y comunidades ahora, al mismo tiempo que proyectan nuevas sociedadesy las relaciones en y para el futuro. Son movimientos con una concepción diferente del tiempo y el espacio. Son movimientos queentienden lo individual y lo colectivo como vinculados entre sí. Hay mucho en común entre la experiencia en la Argentina y las prácticas eideas anarquistas. Eso no significa que los que están creando nuevas relaciones y comunidades en la Argentina sean anarquistas. Lo que este artículo intenta hacer es basarse en las experiencias de los movimientos sociales argentinos para iniciar una reflexión sobre lasprácticas e ideas que los anarquistas pueden prestar a los distintos movimientos y comunidades autónomas; y, a su vez, sobre lo que los movimientos autónomos en la Argentina puede dar a las ideas y prácticas anarquistas.

  10. Discussion of oil pollution in Argentina

    Energy Technology Data Exchange (ETDEWEB)

    1978-06-01

    Oil pollution in Argentina, at the port of Comodora Rivadavia showed signs of long-term oil pollution of a nature which would not be tolerated in relation to the exploitation of North Sea oil. The field is operated by Yacimientos Petroliferos Fiscales (Argentine), produces 70,000 bbl/day of oil from onshore and offshore wells, and has been in operation since 1907. A very marked ''tideline'' of bituminous oil residues contaminates the harbor installations and completely covers the pebbles, boulders, and rocks in the intertidal region. This material is of a considerable thickness and has completely obliterated any form of littoral marine life in these habitats. The sandy beach does not show signs of accumulative oil, and it is used as an important recreational area. Since seriously oiled seabirds can be seen, it is surprising that Patagonian crested ducks, king cormorants, and kelp gulls occur in large numbers but show little sign of oil contamination. The Magellan penguin, which is much less abundant locally, may have been much more vulnerable to the oil.

  11. El MERCOSUR y la Realidad Argentina 2006

    Directory of Open Access Journals (Sweden)

    Luis Felipe Agramunt

    2006-12-01

    Full Text Available Argentina está creciendo fuertemente pero no logra trasladar similar tendencia a sus relaciones comerciales con el exterior. Su competitividad internacional, medida a partir de las capacidades de sus empresas para sostener o ganar mercados internacionales, no es similar a la de otros países del MERCOSUR y por el contrario pierde ventajas a medida que pasan los años. El proceso integrador del MERCOSUR no es causa de dicho debilitamiento sino que, por el contrario y como lo demuestra el desarrollo de otros países del bloque, puede ser un factor crítico para ayudar a mejorar la creación de comercio. Sin embargo, el bloque está sufriendo tensiones que le impiden crecer y consolidarse más y mejor a lo largo de los años. Esta situación afecta al país, ya que se le restan posibilidades de aprovechar dicha ventaja como lo supo hacer en las primeras etapas por medio del efecto de “desvío de comercio”. Los esfuerzos cotidianos de los hombres de negocios para hacer posible un MERCOSUR más fuerte y con menos tensiones, a partir de acciones continuas y permanentes, deben ser acompañados por acciones políticas en igual sentido y resolución pronta y justa de las tensiones internas

  12. Status of RERTR activities in Argentina

    International Nuclear Information System (INIS)

    Alvarez, L.; Boero, N.; Pasqualini, E.; Echenique, P.; Ruggirello, G.; Taboada, H.

    2003-01-01

    CNEA, the Atomic Energy Commission of Argentina, has defined development and fabrication activities related with the main fields of the RERTR program. This includes the qualification of high-density fuels for research reactors, the production of radioisotopes from LEU targets and the reduction of the HEU inventory. This paper continues previous presentations in past RERTR meetings and summarizes the main activities performed in these fields during 2002- 2003 and future works. The main part of the CNEA U 3 Si 2 Qualification Program will be completed within this year. The irradiation of the first fuel element was finished and the activities are mainly focused on its PIE works. Regarding the UMo field, development works to provide support for fuel plate fabrication process and to improve understanding of UMo-Al interaction are on progress. Depending on the results of the fuel plate fabrication setup, the manufacturing of full size FE for UMo qualification program could take place during 2004. A program related with the UMo monolithic fuel is also in progress. In the radioisotopes field LEU targets have replaced HEU-Al alloy targets for routine Mo-99 production since November 2002. CNEA approach to minimize the Argentine HEU inventory is also presented (author)

  13. [Insulin and diabetes control in Argentina].

    Science.gov (United States)

    Gagliardino, Juan J; Costa Gil, José E; Faingold, María C; Litwak, León; Fuente, Graciela V

    2013-01-01

    As in the rest of the world, there is a significant gap between scientific knowledge regarding diabetes mellitus and the daily practice outcome, in Argentina. Inadequate diabetes control combined with associated cardiovascular risk factors are responsible for an elevated morbid-mortality incidence and the consequent raise in the socioeconomic burden. Some of the factors leading to this situation are the late diagnosis of the disease, the clinical "inertia" (reluctance to prescribe insulin) and the poor education given to the health care team as well as the persons with diabetes. The implementation of a national diabetologic education program targeting health care providers, the persons with diabetes and their families, could contribute to optimize the appropriate insulin prescription, and consequently improve their life quality, while reducing the disease socioeconomic burden. In order to optimize the education program's strategy outcome, insulinization cabinets should be incorporated, the participation of all health systems (public health, social security and private health insurance companies), the media, health sciences, schools and the pharmaceutical industry are needed.

  14. Psychotherapy, psychoanalysis and urban poverty in Argentina.

    Science.gov (United States)

    Epele, Maria Esther

    2016-12-01

    Based on ethnographic research carried out in the Buenos Aires Metropolitan Area, this paper examines the views of social actors on the psychoanalytically-oriented psychotherapy focused on marginalized populations. From Foucault's perspective on the forms of truth-telling, the aim of this paper is to analyze, as a preliminary research report, treatments according to the native ways of speaking and listening, which dominate the description of therapeutic experiences of patients who come to the treatment without any professional intermediation. The neoliberal transformations of the past decades in Argentina changed both the landscape of the public health system and the daily lives of marginalized people. Considering such changes, this paper examines the ways in which verbal actions (speaking and listening) take place in psychotherapy and mark the course not only of treatments but also the temporal rhythms of their development, and their various levels of efficacy. Finally, the discussion focuses on how ways of speaking and listening in treatments are modeled not only by institutional dynamics but also by the characteristics these verbal activities take in everyday life under the logics of power that prevail over them.

  15. Argentina's chemical makers seek government support

    International Nuclear Information System (INIS)

    Salles, F.

    1993-01-01

    Argentina's chemical industry association, Camara de la Industria Quimica y Petroquimica (CIQYP; Buenos Aires), has started negotiations with the government aiming to stem industry-wide losses, which reached $236 million during the past 18 months. CIQYP blames the poor performance on worldwide over-supply and falling prices, which have curbed exports, and low tariffs, which have spurred imports. It is calling for higher import tariffs and export incentives. The talks will also focus on a possible bond issue that would support companies willing to restructure and modernize operations. The main factor hindering competitiveness is what CIQYP president Alejandro Achaval calls Argentinean cost, including high energy costs, high provincial and federal taxes, and high financing charges. Since 1988, the industry has cut prices by 30%, formed mergers and joint ventures, closed 11 plants and started five new ones, slashed the workforce by 27%, and engaged in the government's privatization program. Meanwhile, plans to privatize 64% of aromatics producer Petroquimica General Mosconi(PGM) were derailed when potential bidders Diamond Shamrock, Shell, and Perez Companc refused for the second time to make offers on February 2. Jorge Olazabal, planning secretary of the Ministry of Defense, says PGM will be put up for sale again by March

  16. El derecho del autor asalariado en Argentina

    Directory of Open Access Journals (Sweden)

    Augusto H. L. Arduino

    2013-11-01

    Full Text Available El autor contratado bajo relación de dependencia laboral en la Argentina no se encuentra regulado en la legislación sobre derecho de autor. La ley número 11723 no contempla la figura, y la reforma de la ley número 25.036 en su art. 2 solo hace referencia a los programas de computación realizados en virtud de un contrato laboral. No obstante, la ley de patentes número 24481 modificada por ley número 24572, ha regulado la cuestión de los derechos de explotación de patentes de invención, mediando relación contractual. Asimismo se ha regulado en ley número 20.744 lo relativo a las invenciones del trabajador. En la ley de patentes de invención se regula la situación del inventor contratado o asalariado. El derecho laboral y la propiedad intelectual en general, y en particular el derecho de autor son de naturaleza diversa y tienen regulaciones específicas con principios jurídicos propios. Por ello, se abordará cada temática desde su generalidad a fin de arribar al tratamiento del problema planteado.

  17. docentes de escuelas públicas argentinas

    Directory of Open Access Journals (Sweden)

    Ana Lía Kornblit

    2013-01-01

    Full Text Available Se analizan los datos de una encuesta a docentes de escuelas públicas de Argentina que realizaron el curso virtual dictado por el Programa de Educación Sexual Integral del Ministerio de Educación. El objetivo fue analizar las opiniones, creencias y actitudes de los docentes sobre temas relacionados a la sexualidad, el derecho al aborto, la diversidad sexual, la equidad de género y el género y la sexualidad. La muestra del estudio estuvo compuesta por 585 docentes. Para el análisis de los datos se utilizaron métodos multivariantes. Los resultados muestran que los estereotipos relacionados con el sexismo y la diversidad sexual varían considerablemente en cuanto a su repre- sentación estadística según las regiones del país. Por lo tanto, el mapa de las con- cepciones de los docentes sobre estos temas muestra una marcada heterogeneidad según regiones geográficas.

  18. Deep geological disposal research in Argentina

    International Nuclear Information System (INIS)

    Ninci Martinez, Carlos A.; Ferreyra, Raul E.; Vullien, Alicia R.; Elena, Oscar; Lopez, Luis E.; Maloberti, Alejandro; Nievas, Humberto O.; Reyes, Nancy C.; Zarco, Juan J.; Bevilacqua, Arturo M.; Maset, Elvira R.; Jolivet, Luis A.

    2001-01-01

    Argentina shall require a deep geological repository for the final disposal of radioactive wastes, mainly high-level waste (HLW) and spent nuclear fuel produced at two nuclear power plants and two research reactors. In the period 1980-1990 the first part of feasibility studies and a basic engineering project for a radioactive high level waste repository were performed. From the geological point of view it was based on the study of granitic rocks. The area of Sierra del Medio, Province of Chubut, was selected to carry out detailed geological, geophysical and hydrogeological studies. Nevertheless, by the end of the eighties the project was socially rejected and CNEA decided to stop it at the beginning of the nineties. That decision was strongly linked with the little attention paid to social communication issues. Government authorities were under a strong pressure from social groups which demanded the interruption of the project, due to lack of information and the fear it generated. The lesson learned was: social communication activities shall be carried out very carefully in order to advance in the final disposal of HLW at deep geological repositories (author)

  19. [Governance of PHC development in Rosario, Argentina].

    Science.gov (United States)

    Báscolo, Ernesto; Yavich, Natalia

    2010-01-01

    Describing the development of PHC policy as promoted by Rosario Municipality (Argentina). A case-study was carried out during 2007 and 2008. Data was collected from secondary and primary sources (interviews, organisational census and observations). PHC development stages were identified by recognising the social norms which produced institutional change and transformation in municipal health services structure and health care and management models. The prevailing modes of governance in each stage were reconognised and characterised (clan, hierarchy and/or incentives). Four stages were identified between 1990 and 2008: 1990-1995/hierarchical mode: primary health care level organisation autonomied from hospitals. 1995-2000/ clan mode: developing of participatory managerial boards and community participation. 2000-2004/ clan mode: maturation of the "PHC movement" in competition with hospitals. 2004-2008/ clan-hierarchical mode: "movement's" crisis and constructions of norms tending towards enhancing an integrated network. Strengthening and empowering first-level health-care produced innovation favouring: the consolidation of a "PHC movement" having strong social commitment and improved services performance. The clan governance mode (regulating collective action via voluntary adhesion to shared values) was crucial for developing PHC between 1995 and 2004. Later on, the movement's fragmentation and the challenges of integrating the health system required developing hierarchical regulation mechanisms to complement the governance clan mode regulation.

  20. Tracing the Iodine-129 fallout in Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Niello, Jorge; Negri, Agustin; Arazi, Andres [Comision Nacional de Energia Atomica (CNEA), Buenos Aires (Argentina). Lab. TANDAR; Wallner, Anton [The Australian National University, Canberra (Australia). Dept. of Nuclear Physics; Niello, Jorge Fernandez [Universidad Nacional de San Martin, Campus Miguelete, Buenos Aires (Argentina)

    2012-07-01

    Full text: Long-lived {sup 129}I (half-life=15.6 Ma) is produced naturally by irradiation of atmospheric xenon by cosmic neutrons and in the sub-surface by spontaneous fission of {sup 238}U, from which the natural inventory of {sup 129}I has been estimated to be around 50,000 kg, only 140 kg of them corresponds to the hydrospheric inventory. Nuclear tests and accidents have added between 45-130 kg. Apart from a global atmospheric fallout component, {sup 129}I has been released from several nuclear fuel reprocessing plants located in the Northern Hemisphere (ca. 6000 kg) which serve as localized sources in oceanographic-tracer experiments. In this presentation, we report results from a study exploring the presence of {sup 129}I in the Southern Hemisphere by determining {sup 129}I/{sup 127}I isotopic ratios in water samples (rivers, lakes and shallow sea-water) taken at different latitudes in Argentina including Antarctica. The iodine-127 and iodine-129 concentrations were measured via ICP-MS (Inductively Coupled Plasma Mass Spectrometry) and Accelerator Mass Spectrometry (AMS), respectively. Distribution of both isotopes can be understood considering tropospheric circulation patterns, possible sources and regional precipitation patterns. Natural and anthropogenic sources for the Southern Hemisphere and their inventories are discussed. Similar contribution came from natural sources and nuclear tests. Contribution from the nuclear fuel reprocessing plants placed in the Northern hemisphere can be neglected. (author)

  1. Minilivestock in Argentina. Integration with Agricultural Production

    Directory of Open Access Journals (Sweden)

    Biasatti, NR.

    1999-01-01

    Full Text Available The development of alternative agricultural production can take different forms. In Argentina there is an important diversity of species available to be incorporated into production systems, giving support for the use of natural resources based on taking advantage of the regional fauna. Moreover the use of different animal species can be incorporated under the concept of the optimization of flows of energy and materials, tending to minimize the environmental impact of livestock production, and also to make more efficient use of the ingredients required for developing the activity. The integration of non-traditional species (minilivestock within the context of sustainable agricultural development was the motivation for the present study A module for raising Myocastor coypus (coypu or false nutha was developed, to which was linked a module for raising Eisenia foetida (the socalled red worm, in both cases with a dual purpose. Preliminary estimates were made of the productive aspects of both species, as well as an analysis of their integration, to understand the extent to which diversification linked with complementation tends to optimize the system.

  2. Natural radionuclides in drinking water in Argentina

    International Nuclear Information System (INIS)

    Bomben, A.M.; Palacios, M.A.

    2000-01-01

    As part of the national survey to evaluate natural radioactivity in the environment, concentration levels of natural uranium and 226 Ra have been analyzed in over 300 drinking water samples taken from different locations in Argentina. 226 Ra was determined by 222 Rn emanation and liquid scintillation counting, and natural uranium by a fluorimetric procedure. Values ranging from 0.03 to 24 μg.l -1 of natural uranium and from 0.06 to 50 μg.l -1 , were measured on drinking water samples taken from tap water systems and private wells, respectively. Concentrations up to 15 mBq.l -1 and to 22 mBq.l -1 of 226 Ra were found in drinking water samples taken from tap water systems and private wells, respectively. These values are compared with the reference values accepted for drinking water. Based on the water intake rate, the age distribution and the measured concentrations, an annual collective effective dose of 1.9 man Sv and an individual committed effective dose of 0.49 μSv.y -1 were calculated for the city of Buenos Aires adult inhabitants, for the ingestion of both natural radionuclides analyzed in drinking water. (author)

  3. Observatorios de Desarrollo Territorial Sustentable Mendoza, Argentina.

    Directory of Open Access Journals (Sweden)

    María Elina Gudiño

    2015-03-01

    Full Text Available El observatorio de Desarrollo territorial Sustentable para Mendoza, Argentina surge en el marco de la ley 8051/09 de Ordenamiento Territorial y Usos del Suelo. Se trata de una herramienta de comunicación para la validación y el monitoreo de indicadores, políticas, planes, programas y proyectos de índole territorial. El marco teórico-metodológico se sustenta en los principios del ordenamiento territorial y el enfoque de sistemas complejos adaptativos. La estructura se diseña en una plataforma tecnológica que permite estandarizar datos, sistematizar información, construir indicadores territoriales y publicar cartografía. Una vez logrado el prototipo, se conforma “Red Territorio” como modelo de gestión que permite interactuar entre instituciones del sector público, privado, científico y ONG. Actualmente, se está trabajando en la vinculación con las instituciones que formarán parte de la experiencia piloto de Red territorio y en el ajuste de la plataforma informática que le dará sustento.

  4. Medical response to radiation emergencies in Argentina

    International Nuclear Information System (INIS)

    Gisone, Pablo A.; Perez, Maria del R.; Dubner, Diana L.; Michelin, Severino C.; Vazquez, M.; Demayo, O.

    2006-01-01

    Although radiation accidents are not frequent, the increasing use of radioisotopes in medicine and industry increases the likelihood of such accidental situations. Additionally, risks posed by the malevolent use of radiation sources have been highlighted during the last few years. In this context, the enhancement of national capabilities for medical assistance of victims in radiation emergencies becomes relevant. This communication describes the organization of medical response to radiation emergencies existing in Argentina. A three-level system for medical response has been developed: pre-hospital response given on-site by local emergency services, assistance provided by emergency departments of local general hospitals and central reference hospitals for treatment of acute radiation syndrome, cutaneous radiation syndrome and internal contamination. An education and training program is regularly executed at the three levels, including theoretical background as well as practical training. Guidelines and protocols for medical handling of victims have been elaborated and implemented. Research and development of new strategies for diagnosis and treatment of radiation injuries are promoted by ARN in close collaboration with physicians belonging to reference hospitals. (author)

  5. el sistema de salud en Argentina

    Directory of Open Access Journals (Sweden)

    Víctor Abramovich

    2008-01-01

    Full Text Available As an answer to the new disparities and inequities which emerged from the health reforms in Argentina form the 1990´s, it appears the need to guarantee the health as a right. As a consequence, an important judicial activism begins to unfold in order to achieve greater guarantees in matters of health. Here, judicial activism refers to the strategic use of the law courts by organizations dedicated to the struggle of public interest and to the use of the law courts by private individuals to channel the complaints against the State or against health service providing companies. At present, both the Supreme National Court of Justice and the lower courts have dealt with an important number of cases related to the right to health. In the cases selected in this article, we analyze the type of conflict and the judicial answer, together with the possible effects of certain court decisions about the rules that govern the health system as finally conformed

  6. Geochronology, geochemistry and tectonic evolution of the Western and Central cordilleras of Colombia

    Science.gov (United States)

    Villagómez, Diego; Spikings, Richard; Magna, Tomas; Kammer, Andreas; Winkler, Wilfried; Beltrán, Alejandro

    2011-08-01

    Autochthonous rocks of the pre-Cretaceous continental margin of NW South America (the Tahami Terrane) are juxtaposed against a series of para-autochthonous rock units that assembled during the Early Cretaceous. Allochthonous, oceanic crust of the Caribbean Large Igneous Province collided with and accreted onto the margin during the Late Cretaceous. We present the first regional-scale dataset of zircon U-Pb LA-ICP-MS ages for intrusive and metamorphic rocks of the autochthonous Tahami Terrane, Early Cretaceous igneous para-autochthonous rocks and accreted oceanic crust. The U-Pb zircon data are complemented by multiphase 40Ar/ 39Ar crystallization and cooling ages. The geochronological data are combined with whole rock major oxide, trace element and REE data acquired from the same units to constrain the tectonic origin of the rock units and terranes exposed in the Western Cordillera, Cauca-Patía Valley and the Central Cordillera of Colombia. The Tahami Terrane includes lower Paleozoic orthogneisses (~ 440 Ma) that may have erupted during the active margin stage of the Rheic Ocean. Basement gneisses were intruded by Permian, continental arc granites during the final assembly of Pangea. Triassic sedimentary rocks were subsequently deposited in rift basins and partially melted during high-T metamorphism associated with rifting of western Pangea during 240-220 Ma. Continental arc magmatism during 180-145 Ma is preserved along the whole length of the Central Cordillera and was followed by an Early Cretaceous out-board step of the arc axis and the inception of the Quebradagrande Arc that fringed the continental margin. Back-stepping of the arc axis may have been caused by the collision of buoyant seamounts, which were coeval with plateau rocks exposed in the Nicoya Peninsular of Costa Rica. Rapid westward drift of South America closed the Quebradagrande basin in the late Aptian and caused medium-high P-T metamorphic rocks of the Arquía Complex to exhume and obduct onto

  7. Geochronologic evidence for a possible MIS-11 emergent barrier/beach-ridge in southeastern Georgia, USA

    Science.gov (United States)

    Markewich, H.W.; Pavich, M.J.; Schultz, A.P.; Mahan, S.A.; Aleman-Gonzalez, W. B.; Bierman, P.R.

    2013-01-01

    Predominantly clastic, off-lapping, transgressive, near-shore marine sediment packages that are morphologically expressed as subparallel NE-trending barriers, beach ridges, and associated back-barrier areas, characterize the near-surface stratigraphic section between the Savannah and the Ogeechee Rivers in Effingham County, southeastern Georgia. Each barrier/back-barrier (shoreline) complex is lower than and cut into a higher/older complex. Each barrier or shoreline complex overlies Miocene strata. No direct age data are available for these deposits. Previous researchers have disagreed on their age and provenance. Using luminescence and meteoric beryllium-10 (10Be) inventory analyses, we estimated a minimum age for the largest, westernmost, morphologically identifiable, and topographically-highest, barrier/beach-ridge (the Wicomico shoreline barrier) and constrained the age of a suite of younger barrier/beach-ridges that lie adjacent and seaward of the Wicomico shoreline barrier. At the study site, the near-shore marine/estuarine deposits underlying the Wicomico shoreline barrier are overlain by eolian sand and an intervening zone-of-mixing. Optically stimulated luminescence (OSL) data indicate ages of ≤43 ka for the eolian sand and 116 ka for the zone-of-mixing. Meteoric 10Be and pedostratigraphic data indicate minimum residence times of 33.4 ka for the eolian sand, 80.6 ka for the zone-of-mixing, and 247 ka for the paleosol. The combined OSL and 10Be age data indicate that, at this locality, the barrier/beach ridge has a minimum age of about 360 ka. This age for the Wicomico shoreline-barrier deposit is the first for any Pleistocene near-shore marine/estuarine deposit in southeast Georgia that is conclusively older than 80 ka. The 360-ka minimum age is in agreement with other geochronologic data for near-coastline deposits in Georgia and South Carolina. The geomorphic position of this barrier/beach-ridge is similar to deposits in South Carolina considered to be

  8. Geochronology and Fluid-Rock Interaction Associated with the Nopal I Uranium Deposit, Pena Blanca, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    M. Fayek; P. Goodell; M. Ren; A. Simmons

    2005-07-11

    The Nopal I uranium (U) deposit, Pena Blanca District, Mexico, largely consists of secondary U{sup 6+} minerals, which occur within a breccia pipe mainly hosted by the 44 Ma Nopal and Colorados volcanic formations. These two units overly the Pozos conglomerate formation and Cretaceous limestone. Three new vertical diamond drill holes (DDHs) were recently drilled at Nopal I. DDH-PB1 with continuous core was drilled through the Nopal I deposit and two additional DDHs were drilled {approx}50 m on either side of the cored hole. These DDHs terminate 20 m below the current water table, thus allowing the detection of possible gradients in radionuclide contents resulting from transport from the overlying uranium deposit. Primary uraninite within the main ore body is rare and fine-grained ({approx}50 micrometers), thus making geochronology of the Nopal I deposit very difficult. Uranium, lead and oxygen isotopes can be used to study fluid-uraninite interaction, provided that the analyses are obtained on the micro-scale. Secondary ionization mass spectrometry (SIMS) permits in situ measurement of isotopic ratios with a spatial resolution on the scale of a few {micro}m. Preliminary U-Pb results show that uraninite from the main ore body gives an age of 32 {+-} 8 Ma, whereas uraninite from the uraniferous Pozos conglomerate that lies nearly 100 m below the main ore body and 25 meters above the water table, gives a U-Pb age that is <1 Ma. Oxygen isotopic analyses show that uraninite from the ore body has a {delta}{sup 18}O = -10.8{per_thousand}, whereas the uraninite within the Pozos conglomerate has a {delta}{sup 18}O = +1.5{per_thousand}. If it is assumed that both uraninites precipitated from meteoric water ({delta}{sup 18}O = -7{per_thousand}), then calculated precipitation temperatures are 55 C for the uraninite from the ore body and 20 C for uraninite hosted by the Pozos conglomerate. These temperatures are consistent with previous studies that calculated precipitation

  9. The Aegean/Cycladic and the Basin and Range Extensional Provinces - A Tectonic and Geochronologic Perspective

    Science.gov (United States)

    Stockli, D. F.

    2017-12-01

    petrochronology, detrital geochronology, and high- and low-T thermochronometry allow us to elucidate pre-extensional crustal geometries, differentiate contractional from extensional fabrics, and understand the thermal and rheological evolution of these extensional provinces in a more holistic fashion.

  10. Petrogenesis of Malaysian tin granites: geochemistry, fractional crystallization, U-Pb zircon geochronology and tectonic setting

    Science.gov (United States)

    Wai-Pan Ng, Samuel; Searle, Mike; Whitehouse, Martin; Chung, Sun-Lin; Ghani, Azman; Robb, Laurence; Sone, Masatoshi; Oliver, Grahame; Gardiner, Nick; Roselee, Mohammad

    2014-05-01

    The Malaysian tin granites forming the backbone of the Thai-Malay Peninsula has been long recognized with two distinct granitic provinces:- 1. Early Permian to Late Triassic Eastern Province with mainly "I-type" (Hbl)-Bt granites with associated Cu-Au deposits, with subordinate Bt granites hosting limited Sn-W deposits, and 2. Late Triassic Main Range Province with mainly "S-type" Bt granites with associated Sn-W deposits, and subordinate (Hbl)-Bt granites. New geochemical data show that Chappell and White's (1974) I-S granite classification adopted in the existing model does not adequately distinguish the granites from one another as previously implied. Trace element geochemistry and Sr-Nd isotopic compositions show that the Malaysian tin granites in both provinces have transitional I-S characteristics. In addition, they inherited within-plate signature from Cambro-Ordovician Gondwana-related source rocks. Previous ages were obtained by whole rock Rb-Sr and biotite K-Ar geochronology in the 70s and 80s, dating methods that may not accurately represent the crystallization age of granites. We re-sampled the entire Malaysian Peninsula and 40 samples were collected for high-precision U-Pb SIMS dating on extracted zircon grains in order to better constrain the magmatic and tectonic evolution of Southeast Asia. The crystallization ages of the Eastern Province granitoids have been constrained ranging from 220 to 290 Ma, while the Main Range (Western) Province granitoids have ages ranging from 200 to 230 Ma. A progressive westward younging trend is apparent across the Eastern Province, but becomes less obvious in the Main Range Province. Our model suggests two east dipping subduction zones. We suggest that subduction roll-back along the Bentong-Raub suture might account for the westward younging trend, in the Eastern province. A second Late Triassic east-dipping subduction zone beneath western Malaysia is proposed in order to explain the "I-type" components to the Main

  11. Regional setting and geochronology of the Late Cretaceous Banatitic Magmatic and Metallogenetic Belt

    Science.gov (United States)

    Ciobanu, Cristiana L.; Cook, Nigel J.; Stein, Holly

    2002-08-01

    The 1,500-km-long Banatitic Magmatic and Metallogenetic Belt (BMMB) of Romania, Serbia and Bulgaria is a complex calc-alkaline magmatic arc of Late Cretaceous age. It hosts a variety of magmatic-hydrothermal Cu, Au, Mo, Zn, Pb and Fe deposits, including Europe's only world-class porphyry-copper deposits. Regional metallogeny can be linked to subduction of the Vardar Ocean during the Late Cretaceous, as part of the closure of the Neotethys Ocean that had separated Europe and Africa in the Mesozoic. Porphyry Cu-(Au)-(Mo) and intimately associated epithermal massive sulphides dominate in the central segments of the belt in southernmost Banat (Romania), Serbia and north-west Bulgaria. These districts are the economically most important today, including major active Cu-Au mines at Moldova Nouă in Romania, Majdanpek, Veliki Krivelj and Bor in Serbia, and Elatsite, Assarel and Chelopech in Bulgaria. More numerous (and mostly mined in the past) are Fe, Cu and Zn-Pb skarns, which occur mainly at the two ends of the belt, in Eastern Bulgaria and in Romania. This paper summarises some of the deposit characteristics within the geodynamic framework of terminal Vardar subduction. Heterogeneous terranes of the belt, including the Apuseni Mountains at the western end, are aligned parallel to the Vardar front following continental collision of the Dacia and Tisza blocks. All available geochronological data (numerous K-Ar and some U-Pb and Re-Os ages) are compiled, and are complemented by a new high-precision Re-Os date for the Dognecea skarn deposit, south-west Romania (76.6±0.3 Ma). These data indicate that magmatism extended over at least 25 million years, from about 90 to 65 Ma in each segment of the belt. Within Apuseni Mountains and Banat, where magma emplacement was related to syn-collisional extension in the orogenic belt of Carpathians, ore formation seems to be restricted in time and maybe constrained by a shared tectonic event.

  12. Geochronological data for lithostratigraphic complexes of a crystalline basement from the South regions of Minas Gerais and adjacent areas of the Sao Paulo state

    International Nuclear Information System (INIS)

    Kawashita, K.; Artur, A.C.; Wernick, E.

    1988-01-01

    New geochronological data (Rb/Sr, Pb/Pb) for the Amparo and Pinhal Complexes, southern State of Minas Gerais and adjacent areas of the State of Sao Paulo are presented and discussed with respect to other lithostratigraphic complexes which there occur. Among the different complexes considered, 4 are composed mainly by rock belonging to typical infrastructure associations. They are the Barcelona, the Guaxupe, the Amparo and the Pinhal complexes. The Barbacena Complex is a typical gray gneiss complex and geochronological data by different methods confirm its Archean age. The Guaxupe Complex is composed mainly by different types of charnockitic rocks and an Archean age is assumed on geotectonic basis due to its neighboring association with the gray gneiss/greenstone belt, a though confirming geochronological data are still missing, a normal feature in this type of mobile belts which generally show a complex, polycyling evolution. Geochronological data by different methods on diverse rock types indicates that the Amparo and Pinhal complexes are respectively of Lower an Upper proterozoic age. Geochronological, geological and petrographic data reveal that both complexes are composed mainly by 3 basic rock associations: a-mainly derived magmatic rocks including mafic/ultramafic ones as well as calc-alkaline, subalcaline and even alkaline granitoids; b-orthogneisses, migmatites and crustal granites derived by metamorphic processes acting on older, pre-existing rocks; corthogneisses and migmatites resulting from metamorphic processes acting on magmatic rocks intruded during the same tecto-metamorphic cycle during which its transformation took place. The results suggest a polycyclic evolution by successive tecto-metamorphic events which affected the older rocks of the considered are either by the reworking of enclosing rocks around pericratonic continental main magmatic arcs or by the remobilisation of older basement rocks during continental collisions. (author) [pt

  13. The blue land planarian Caenoplana coerulea, an invader in Argentina La planaria terrestre azul Caenoplana coerulea, un invasor en Argentina

    Directory of Open Access Journals (Sweden)

    Lisandro Héctor Luis-Negrete

    2011-03-01

    Full Text Available The blue land planarian Caenoplana coerulea is reported from Argentina (Buenos Aires province. We found C. coerulea in the east central region of Argentina in anthropic environments. The specimens that we found have the characteristic of the species found in others regions; that is, a bluish dorsal surface with a yellow mid-dorsal stripe and eyes forming a single row around the anterior tip, clustered laterally. This is the first record of this species from the Neotropical Region, and together with Bipalium kewense are the only 2 species of exotic terrestrial planarians so far recorded in Argentina.La planaria terrestre azul Caenoplana coerulea se registra para el centro este de Argentina (provincia de Buenos Aires, en ambientes antropizados. Los ejemplares encontrados presentan las características de la especie registrada en otras regiones, con una superficie dorsal azulada y una hilera medio dorsal amarilla, y ojos formando una hilera alrededor del extremo anterior, agrupados lateralmente. Es la primera vez que se cita dicha especie en la Región Neotropical, y junto a Bipalium kewense son las únicas planarias terrestres exóticas registradas en Argentina.

  14. Biotechnology in Argentina: New products, new multilateral challenges

    Directory of Open Access Journals (Sweden)

    Luciano M. Donadio Linares

    2016-06-01

    Full Text Available Since 20 years ago, a public-private alliance has transformed Argentina into a remarkable global actor in developing biotechnological products for food and renewable energies. This strategic alliance resulted in the boosting of scientific knowledge, the extension of the production boundary, the expansion of international trade and the creation of the conditions for an integral development. Furthermore, given the characteristics of biotechnology as a new phenomenon, wto has become the field within where a number of disputes take place, disputes which not only controvert trade issues, but also the State’s limits to design and apply public policies on the matter at issue. As a consequence, the present article seeks to, on the one hand, describe how Argentina built its public policy on Biotechnology and, on the other hand, analyze the challenges that Argentina faces within the multilateral trade system

  15. Tareas que realizan los bibliotecarios universitarios en Argentina

    Directory of Open Access Journals (Sweden)

    Werner Agazzi

    2011-08-01

    Full Text Available El presente estudio es una investigación descriptiva que pretende conocer las tareas que realizan los bibliotecarios en las bibliotecas universitarias argentinas, abordando el tema desde la perspectiva de las competencias laborales y el actual perfil del bibliotecario universitario. Mediante la utilización de un cuestionario enviado a las direcciones de e-mail de bibliotecas universitarias argentinas se compilaron datos sobre las tareas que realizan los bibliotecarios en esas instituciones. A través de este proceso también se compilaron datos relacionados con las tareas de comunicación vía e-mail por parte de las bibliotecas universitarias argentinas.

  16. The regulatory control of radioactive sources in Argentina

    International Nuclear Information System (INIS)

    Rojkind, R.H.

    1998-01-01

    Argentina has been conducting nuclear activities for more than forty years, and had established a Regulatory Authority as early as in 1956. Procedures for compliance monitoring and enforcement have been in use in the regulatory control of radioactive sources, and regulatory standards and regulations were in force in Argentina before the accident in Goiania. The conclusions drawn from the Goiania accident encouraged the Argentine authorities to improve some regulatory procedures and helped to enhance the quality of the regulatory process. As a result, the effectiveness of the control of spent radioactive sources has gradually increased, and enforcement actions to prevent radioactive sources ending up in the public domain have improved. Lessons learned in Argentina from the accident in Goiania are presented as well as the main characteristics of an effective enforcement programme to prevent radiological accidents when radioactive sources are used for industrial, medical, research and teaching purposes. (author)

  17. Tribulations and achievements: the early history of Olympism in Argentina.

    Science.gov (United States)

    Torres, C R

    2001-01-01

    By the end of the nineteenth century, modern sport had enchanted the people of Argentina. At that time the nation enjoyed a remarkable degree of economic prosperity and embarked on increasing political democratization. These circumstances, along with the fact that the nation was represented from the beginning, in 1894, on the International Olympic Committee seemed to favour Argentina as the spearhead of the diffusion of Olympism throughout South America. However, the country only enjoyed its first official Olympic participation in the Paris Games of 1924 - a few months after the establishment of the Argentine Olympic Committee. This essay explores the reception and diffusion of Olympism in Argentina. It reveals a process of gradual adoption including conflicting views on the relationship between the state and sport, several attempts at institutionalization, international misunderstandings and the role of politics and class.

  18. Psychotherapy in Argentina: a clinical case from an integrative perspective.

    Science.gov (United States)

    Gómez, Beatriz

    2007-08-01

    The article describes psychotherapy practice in Argentina. It outlines the main features of training and regulation of clinical psychologists. A brief description of the main treatment approaches and the major current challenges is presented. Subsequently it delineates the probable treatment locations and options for a 30-year-old woman, Mrs. A, seeking psychological help in Argentina. The case is then considered from an integrative perspective starting with the intake process, which includes a comprehensive pretreatment assessment followed by the treatment plan. Its course is described as composed of four stages: (1) psychoeducational initial intervention, (2) psychotherapy for symptom alleviation, (3) marital treatment, and (4) psychoeducational final intervention. Posttreatment evaluation and possible outcome and prognosis are presented, as well as factors that might prevent improvement. The article ends with a hopeful view of the future role of psychotherapy in Argentina. (c) 2007 Wiley Periodicals, Inc.

  19. Time-scale calibration by U-Pb geochronology: Examples from the Triassic Period

    Science.gov (United States)

    Mundil, R.

    2009-05-01

    U-Pb zircon geochronology, pioneered by Tom Krogh, is a cornerstone for the calibration of the time scale. Before Krogh's innovations, U-Pb geochronology was essentially limited by laboratory blank Pb (typically hundreds of nanograms) inherent in the then existing zircon dissolution and purification methods. The introduction of high pressure HF dissolution combined with miniature ion exchange columns (1) reduced the blank by orders of magnitude and allowed mass-spectrometric analyses of minute amounts of material (picograms of Pb and U). Krogh also recognized the need for minimizing the effects of Pb loss, and the introduction of the air-abrasion technique was the method of choice for two decades (2), until the development of the combined annealing and chemical abrasion technique resulted in essentially closed system zircons (3). These are the prerequisite for obtaining precise (permil-level) and accurate radio-isotopic ages of individual zircons contained in primary volcanic ash deposits, which are primary targets for the calibration of the time scale if they occur within fossil bearing sediments. A prime example is the calibration of the Triassic time scale which improved significantly using these techniques. The ages for the base and the top of the Triassic are constrained by U-Pb ages to 252.3 (4) and 201.5 Ma (5), respectively. These dates also constrain the ages of major extinction events at the Permian-Triassic and Triassic-Jurassic boundaries, and are statistically indistinguishable from ages obtained for the Siberian Traps and volcanic products from the Central Atlantic Magmatic Province, respectively, suggesting a causal link. Ages for these continental volcanics, however, are mostly from the K-Ar (40Ar/39Ar) system which requires accounting and correcting for a systematic bias of ca 1 % between U-Pb and 40Ar/39Ar isotopic ages (the 40Ar/39Ar ages being younger) (6). Robust U-Pb age constraints also exist for the Induan- Olenekian boundary (251.2 Ma, (7

  20. In-Situ Geochronology: Extending Larims to Pb-Pb Isocrhons

    Science.gov (United States)

    Whitaker, Tom; Anderson, Scott; Levine, Jonathan

    2016-04-01

    Introduction: We have previously described development of Laser Ablation Resonance Ionization Mass Spectrometry (LARIMS) for in-situ determination of the radiometric age of rocks using isotope ratios of Rb and Sr [1,2]. LARIMS uses laser resonance excitation of the target elements, which provides elemental selectivity, thus eliminating isobaric interferences with little or no sample preparation and allowing thousands of samples to be measured in significantly shorter periods of time than traditional methods. We have recently begun research that aims to extend the Rb-Sr capability to include Pb-Pb measurements. Preliminary measurements of Standard Reference Material 612 (SRM-612) from the National Institute of Standards and Technology (NIST) demonstrate that resonance ionization of Pb can measure samples with as little as 0.12 ppm total Pb. Background: In-situ LARIMS will enable measurements of 1) isotope geochemistry relevant for chronology and igneous evolution, 2) light isotopes relevant for habitability, life, and climate history, as well as 3) elemental abundances relevant to understanding local and regional geology. In particular, the elemental selectivity of LARIMS makes isotopic geochronology measurements possible that heretofore required extensive sample preparation and were thought to be practically impossible for in-situ measurements. For example, we have used Rb-Sr LARIMS to analyze a piece of the Martian meteorite Zagami and the Duluth Gabbro, a lunar analogue. In these measurements, we obtained isochron ages consistent with the published ages within 200 Ma. Pb-Pb geochronology is well-suited for LARIMS analysis. The use of a single element simplifies the laser system and eliminates inter-element fractionation that can be problematic in Rb-Sr analysis or other multi-element LARIMS measurements. In general, there is less interference at masses corresponding to Pb isotopes than at lighter masses. However, there are potential interferences such as Hg and