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Sample records for granulite body bohemian

  1. Low pressure granulites from the Bohemian Massif, Upper Austria

    NASA Astrophysics Data System (ADS)

    Sorger, Dominik; Daghighi, Donia; Simic, Katica; Pichler, Ruth; Schwaiger, Christian; Hauzenberger, Christoph; Linner, Manfred; Iglseder, Christoph

    2014-05-01

    Low pressure granulite facies rocks are commonly found in the Bohemian Massif in Upper Austria. They belong to the Moldanubian Unit and were metamorphosed during the last stage of the Variscan orogeny. The investigated granulites from the Donau valley (west of Linz), Lichtenberg (northwest of Linz), Sauwald (south of the river Danube) and Bad Leonfelden zone comprise mainly migmatic paragneisses. Most of these rocks underwent high degrees of melting forming meta- and diatexites (''Perlgneise)''. Al-rich metapelites with partly cm-sized garnet porphyroblasts, which are suitable for precise PT and PT-path determinations, can be found in some localities of this unit. In this study samples taken along the Danube valley between Linz and Wilhering, from Lichtenberg and from Bad Leonfelden (north of Linz) were sampled and investigated petrographically in detail. Since garnets are rare and usually consumed by cordierite, a sample with large garnets was investigated in detail. A chemical zoning profile across the c. 1cm large garnet displayed elevated Ca contents (Xgrs=0.06) in the central part which decreased discontinuously towards the rim to Xgrs=0.02. Almandine, pyrope and spessartine components do not show any pronounced zoning pattern. Most of the smaller garnet grains in other samples are also homogeneous in composition with a slight Xalm increase and Xprp decrease at the rims, typical for retrograde diffusional zoning. The cordierite-garnet-sillimanite-granulites as well as some mafic granulites were used for geothermobarometry. Metamorphic conditions of around 770°C to 850°C and 0.5-0.6 GPa could be obtained, which are similar to the values obtained by Tropper et al. (2006). P. Tropper I. Deibl F. Finger R. Kaindl (2006). P-T-t evolution of spinel-cordierite-garnet gneisses from the Sauwald Zone (Southern Bohemian Massif, Upper Austria): is there evidence for two independent late-Variscan low-P / high-T events in the Moldanubian Unit? Int J Earth Sci (Geol

  2. Multistage evolution of UHT granulites from the southernmost part of the Gföhl Nappe, Bohemian Massif, Lower Austria

    NASA Astrophysics Data System (ADS)

    Schantl, Philip; Hauzenberger, Christoph; Linner, Manfred

    2016-04-01

    A detailed petrological investigation has been undertaken in leucocratic kyanite-garnet bearing and mesocratic orthopyroxene bearing granulites from the Dunkelsteiner Wald, Pöchlarn-Wieselburg and Zöbing granulite bodies from the Moldanubian Zone in the Bohemian Massif (Austria). A combination of textural observations, conventional geothermobarometry, phase equilibrium modelling as well as major and trace element analyses in garnet enables us to confirm a multistage Variscan metamorphic history. Chemically homogenous garnet cores with near constant grossular-rich plateaus are considered to reflect garnet growth during an early HP/UHP metamorphic evolution. Crystallographically oriented rutile exsolutions restricted to those grossular-rich garnet cores point to a subsequent isothermal decompression of the HP/UHP rocks. Overgrowing garnet rims show a pronounced zonation and are interpreted as the result of dehydration melting reactions during an isobaric heating phase which could have taken place near the base of an overthickened continental crust, where the previously deeply subducted rocks were exhumed to. For this HP granulite facies event maximum PT conditions of ~1050 °C and 1.6 GPa have been estimated from leucocratic granulites comprising the peak mineral assemblage quartz, ternary feldspar, garnet, kyanite and rutile. The pronounced zoning of garnet rims indicates that the HP granulite facies event must have been short lived since diffusion in this temperature region is usually sufficient fast to homogenize a zoning pattern in garnet. A retrogressive metamorphic stage is documented in these rocks by the replacement of kyanite to sillimanite and the growth of biotite. This retrograde event took place within the granulite facies but at significantly lower pressures and temperatures with ~0.8 GPa and ~760 °C. This final stage of re-equilibration is thought to be linked with a second exhumation phase into middle crustal levels accompanied by intensive

  3. Dating granulite-facies structures and the exhumation of lower crust in the Moldanubian Zone of the Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Svojtka, M.; Košler, J.; Venera, Z.

    2002-05-01

    Deformation of granulite-facies rocks in the Moldanubian Zone of the southern Bohemian Massif is expressed in two intersecting planar fabrics - steeply disposed (S1) and flat-laying (S2) - which correspond to two deformation stages (D1) and (D2). The existing Sm-Nd garnet ages from banded granulite gneisses, new U-Pb zircon data from deformed granite intrusions within the granulite gneisses, and the P-T and field structural relations constrain the ages and P-T conditions of the two deformation phases. The early deformation (D1) was associated with a HP-HT metamorphic stage with a minimum age of ca. 354 Ma which was followed by a near-isothermal decompression. A concordant U-Pb zircon age of 318±1 Ma dates the emplacement of intrusions of deformed granite into the granulite gneisses and constrains deformation phase (D2). This phase was associated with an LP-HT metamorphism dated in the region at ca. 340-330 Ma. The available structural and isotopic data indicate that granulites in the southern Bohemian Massif were exhumed from lower to middle crust during compression. The structural relations and P-T-t data for the studied granulites are consistent with their exhumation by near-vertical extrusion of the softened orogenic root.

  4. Deformation mechanisms and grain size evolution in the Bohemian granulites - a computational study

    NASA Astrophysics Data System (ADS)

    Maierova, Petra; Lexa, Ondrej; Jeřábek, Petr; Franěk, Jan; Schulmann, Karel

    2015-04-01

    A dominant deformation mechanism in crustal rocks (e.g., dislocation and diffusion creep, grain boundary sliding, solution-precipitation) depends on many parameters such as temperature, major minerals, differential stress, strain rate and grain size. An exemplary sequence of deformation mechanisms was identified in the largest felsic granulite massifs in the southern Moldanubian domain (Bohemian Massif, central European Variscides). These massifs were interpreted to result from collision-related forced diapiric ascent of lower crust and its subsequent lateral spreading at mid-crustal levels. Three types of microstructures were distinguished. The oldest relict microstructure (S1) with large grains (>1000 μm) of feldspar deformed probably by dislocation creep at peak HT eclogite facies conditions. Subsequently at HP granulite-facies conditions, chemically- and deformation- induced recrystallization of feldspar porphyroclasts led to development of a fine-grained microstructure (S2, ~50 μm grain size) indicating deformation via diffusion creep, probably assisted by melt-enhanced grain-boundary sliding. This microstructure was associated with flow in the lower crust and/or its diapiric ascent. The latest microstructure (S3, ~100 μm grain size) is related to the final lateral spreading of retrograde granulites, and shows deformation by dislocation creep at amphibolite-facies conditions. The S2-S3 switch and coarsening was interpreted to be related with a significant decrease in strain rate. From this microstructural sequence it appears that it is the grain size that is critically linked with specific mechanical behavior of these rocks. Thus in this study, we focused on the interplay between grain size and deformation with the aim to numerically simulate and reinterpret the observed microstructural sequence. We tested several different mathematical descriptions of the grain size evolution, each of which gave qualitatively different results. We selected the two most

  5. Exotic crustal components at the northern margin of the Bohemian Massif-Implications from Usbnd Thsbnd Pb and Hf isotopes of zircon from the Saxonian Granulite Massif

    NASA Astrophysics Data System (ADS)

    Sagawe, Anja; Gärtner, Andreas; Linnemann, Ulf; Hofmann, Mandy; Gerdes, Axel

    2016-06-01

    The Saxonian Granulite Massif is located at the northern margin of the Saxo-Thuringian Zone of the peri-Gondwana Bohemian Massif. Eight felsic and mafic granulites were studied with respect to their geochemistry and Usbnd Pb zircon geochronology. The felsic granulites are interpreted to be derived from continental crust of possible granitoid composition. An origin from depleted mantle sources with IAT to MORB composition can be assumed for the mafic granulites. The peak of metamorphism is thought to be timed at about 340 Ma, while several earlier metamorphic events are supposed to have occurred at about 355-360, 370-375, 405, and 450 Ma. They reveal a complex and polyphased geologic evolution of the Saxonian Granulite Massif. Protolith emplacement likely took place at c. 450 and 494 Ma. Hf isotopic data suggest Mesoproterozoic crustal ages at least for parts of the massif. As these crustal ages are exotic for the Bohemian Massif, their origin has to be searched elsewhere. Potential source areas could be Amazonia and Baltica, of which the latter is the one preferred. Furthermore, a composite architecture with at least two components-the felsic granulites with Mesoproterozoic crustal model ages, and the mafic granulites of potential island arc origin-is hypothesised. Their amalgamation to the recent appearance of the Saxonian Granulite Massif is likely bracketed between 375 and 340 Ma.

  6. Evidence of unadulterated mantle-depth, granitic melt inclusions: kumdykolite and kokchetavite crystallized from melt in Bohemian Massif granulites.

    NASA Astrophysics Data System (ADS)

    O´Brien, Patrick J.; Ferrero, Silvio; Ziemann, Martin A.; Walczak, Katarzyna; Wunder, Bernd; Hecht, Lutz; Wälle, Markus

    2016-04-01

    Partial melting under near-UHP conditions of metagranitoids (now HP felsic granulites) at mantle depth in the Orlica-Śnieżnik Dome (Bohemian Massif, Poland) is recorded in small volumes of hydrous melt trapped as primary melt inclusions (MI) in peritectic garnets. When free of cracks connecting the inclusion with the leucocratic matrix, these "nanogranites" (≤ 50μm inclusion diameter) contain a unique assemblage including kumdykolite, kokchetavite and cristobalite - polymorphs of albite, K-feldspar and quartz, respectively. These usually metastable phases crystallized from the melt (glass?) during rapid exhumation (cm/a) at high T but the crack-free state strongly suggests over-pressuring of the inclusion with respect to the pressure-time path followed by the matrix. Reports of both kumdykolite and kokchetavite have been mainly from natural rocks equilibrated in the diamond stability field. The precise calculation of the PT path of the MI on cooling and the comparison with previous studies suggests, however, that pressure is not influential to their formation, ruling out the possible interpretation of kumdykolite and kokchetavite as indicators of ultra-high pressure conditions. Experimental re-homogenization of these crack-free nanogranites was achieved using a piston cylinder apparatus at 2.7 GPa and 875°C. These conditions are consistent with the results of geothermobarometric calculations on the host rock, suggesting that no H2O loss occurred during exhumation as this would have caused a shift of the inclusion melting T toward higher values. Coupled with the absence of H2O-loss microstructural evidence, e.g. decrepitation cracks and/or vesciculation in re-homogenized nanogranites, this evidence suggests that the nanogranites still preserve the original H2O content of the melt. Both experimental and microstructural evidence support the hypothesis that the presence of these polymorphs should be regarded as direct mineralogical criterion to identify former

  7. Coincidence of gabbro and granulite formation and their implication for Variscan HT metamorphism in the Moldanubian Zone (Bohemian Massif), example from the Kutná Hora Complex

    NASA Astrophysics Data System (ADS)

    Faryad, Shah Wali; Kachlík, Václav; Sláma, Jiří; Jedlicka, Radim

    2016-11-01

    Leucocratic metagabbro and amphibolite from a mafic-ultramafic body within migmatite and granulite in the Kutná Hora Complex were investigated. The mafic-ultramafic rocks show amphibolite facies metamorphism, but in the central part of the body some metagabbro preserves cumulus and intercumulus plagioclase, clinopyroxene and spinel. Spinel forms inclusions in both clinopyroxene and plagioclase and shows various degree of embayment structure, that was probably a result of reaction with melt during magmatic crystallization. In the metagabbro, garnet forms coronae around clinopyroxene at the contacts with plagioclase. Amphibolite contains garnet with prograde zoning and plagioclase. Phase relations of igneous and metamorphic minerals indicate that magmatic crystallization and subsequent metamorphism occurred as a result of isobaric cooling at a depth of 30-35 km. U-Pb dating on zircon from leucogabbro yielded a Variscan age (337.7 ± 2 Ma) that is similar or close to the age of granulite facies metamorphism (ca 340 Ma) in the Moldanubian Zone. Based on the calculated PT conditions and age data, both the mafic-ultramafic body and surrounding granulite shared the same exhumation path from their middle-lower crustal position at the end of Variscan orogeny. The coincidence of mafic-ultramafic intrusives and granulite-amphibolite facies metamorphism is explained by lithospheric upwelling beneath the Moldanubian Zone that occurred due to slab break-off during the final stages of subduction of the Moldanubian plate beneath the Teplá Barrandian Block. The model also addresses questions about the preservation of minerals and/or their compositions from the early metamorphic history of the rocks subjected to ultradeep subduction and subsequent granulite facies metamorphism.

  8. Kumdykolite, kokchetavite, and cristobalite crystallized in nanogranites from felsic granulites, Orlica-Snieznik Dome (Bohemian Massif): not an evidence for ultrahigh-pressure conditions

    NASA Astrophysics Data System (ADS)

    Ferrero, Silvio; Ziemann, Martin A.; Angel, Ross J.; O'Brien, Patrick J.; Wunder, Bernd

    2016-01-01

    A unique assemblage including kumdykolite and kokchetavite, polymorphs of albite and K-feldspar, respectively, together with cristobalite, micas, and calcite has been identified in high-pressure granulites of the Orlica-Snieznik dome (Bohemian Massif) as the product of partial melt crystallization in preserved nanogranites. Previous reports of both kumdykolite and kokchetavite in natural rocks are mainly from samples that passed through the diamond stability field. However, because the maximum pressure recorded in these host rocks is <3 GPa, our observations indicate that high pressure is not required for the formation of kumdykolite and kokchetavite, and their presence is not therefore an indicator of ultrahigh-pressure conditions. Detailed microstructural and microchemical investigation of these inclusions indicates that such phases should instead be regarded as (1) a direct mineralogical criteria to identify former melt inclusions with preserved original compositions, including H2O and CO2 contents and (2) indicators of rapid cooling of the host rocks. Thus, the present study provides novel criteria for the interpretation of melt inclusions in natural rocks and allows a more rigorous characterization of partial melts during deep subduction to mantle depth as well as their behavior on exhumation.

  9. High-pressure granulites of the Podolsko complex, Bohemian Massif: An example of crustal rocks that were subducted to mantle depths and survived a pervasive mid-crustal high-temperature overprint

    NASA Astrophysics Data System (ADS)

    Faryad, Shah Wali; Žák, Jiří

    2016-03-01

    The Podolsko complex, Bohemian Massif, is a mid-crustal migmatite-granite dome exposed along a tectonic boundary separating the upper crust from the deeply eroded interior of the Variscan orogen, referred to as the Moldanubian Zone. This study examines metamorphic history of mafic and felsic granulites that occur in this complex as minor lenses or layers hosted in pervasively anatectic rocks. The mafic granulite contains garnet with preserved high-Ca cores, which based on pseudosection modelling indicates pressure conditions near the coesite stability field at temperatures of ca. 550-600 °C. The relicts of an earlier eclogite-facies stage have been overprinted by a later granulite-facies assemblage consisting of ternary feldspar, orthopyroxene, and spinel in the mafic granulite and sillimanite and spinel in the felsic granulite. Composition of younger garnet (in rims and as smaller grains) in both granulites suggests that a near isothermal decompression of these rocks was followed by heating that reached temperature of ca. 900 °C at pressure of ca. 0.5 GPa. It is thus concluded that the granulites underwent at least two temporally separate tectonometamorphic events: they were first subducted to mantle depths and exhumed rapidly at relatively low temperatures and then near isobarically heated at mid-crustal levels. The preservation of earlier eclogite-facies garnet in the mafic granulite indicates that the latter event was short-lived and was followed by near isobaric cooling. The geologically brief granulite-facies metamorphism was previously explained as a result of slab break-off and mantle upwelling after the main phase of microplate convergence in the Bohemian Massif. To put the Podolsko complex into a broader tectonic context, we synthesize the available petrologic and structural data from the correlative (U)HP assemblages of the Moldanubian Zone to suggest that they typically do not preserve structural record of the subduction stage, only rarely preserve an

  10. Partial melting of granitoids under eclogite-facies conditions: nanogranites from felsic granulites from Orlica-Śnieżnik Dome (Bohemian Massif)

    NASA Astrophysics Data System (ADS)

    Ferrero, Silvio; O'Brien, Patrick; Walczak, Katarzyna; Wunder, Bernd; Hecht, Lutz

    2014-05-01

    Melt inclusions (MI) study in migmatites is a powerful tool to retrieve the original composition of the anatectic melt, both as major elements (Ferrero et al., 2012) and fluid contents (Bartoli et al., 2013). Crystallized MI, or "nanogranites" (Cesare et al., 2009), were identified within HP felsic granulites from Orlica-Śnieżnik Dome, NE Bohemian Massif (Walczak, 2011). The investigated samples are Grt+Ky leucogranulites originated from a granitic protolith, with assemblage Qtz+Pl+Kfs+Grt+Ky+Ttn+Rt+Ilm. Nanogranites occur in garnet as primary inclusions, and consist of Qtz+Ab+Bt+Kfs±Ep±Ap. Such assemblage results from the crystallization of a melt generated during a partial melting reaction; the same reaction is also responsible for the production of the host garnet, interpreted therefore as a peritectic phase. Besides nanogranites, former presence of melt is supported by the occurrence of tiny pseudomorphs of melt-filled pores (Holness & Sawyer, 2008) and euhedral faces in garnet. Garnet composition, with Grs =0.28-0.31, phase assemblage (kyanite, ternary feldspar) and classic thermobarometry suggest that partial melting took place at T≥875°C and P~2.2-2.6 GPa, under eclogite-facies conditions. Although other authors reported palisade quartz after coesite in this area (see e.g. Bakun-Czubarow, 1992), no clear evidence of UHP conditions have been identified during this study. Piston cylinder re-homogenization experiments were performed on MI-bearing garnet chips to obtain the composition of the pristine anatectic melt. The first data from experiments in the range 850-950°C and 2-2.2 GPa show that nanogranites can be re-melted at T≥875°. However, homogenization has not been reached yet since new Grt, with lower CaO and higher MgO, crystallizes on the walls of the inclusion. As P increases, the modal amount of new phase decreases, while its composition evolves closer to those of the host garnet. Further experiments at higher pressure are in underway, with

  11. First finding of microdiamond, coesite and other UHP phases in felsic granulites in the Moldanubian Zone: Implications for deep subduction and a revised geodynamic model for Variscan Orogeny in the Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Perraki, Maria; Faryad, Shah Wali

    2014-08-01

    Heavy mineral fractions and polished thin sections from felsic granulites from the Moldanubian Zone of the Bohemian Massif were thoroughly studied by means of Raman microspectroscopy combined with optical microscopy and scanning electron microscopy. The following phases were identified, among others, as inclusions in robust minerals such as garnet and zircon: Diamond, characterized by an intense narrow peak at 1332 cm- 1, was found in two inclusions in zircon. They have a size of ~ 5 μm. Coesite, identified by its very characteristic peak at ~ 520 cm- 1, was found in an inclusion in garnet together with quartz. Coesite has been almost completely transformed into quartz; only minor coesite nano-domains remain. Kumdykolite, the orthorhombic polymorph of NaAlSi3O8, characterized by strong peaks at 220, 456 and 492 cm- 1, occurs either as single crystals or as a part of multiphase inclusions in garnet and in zircon along with other mineral phases such as K-feldspar, phengite, rutile. Moissanite, SiC, exhibiting the characteristic Raman bands at ~ 767, 788 and 969 cm- 1, occurs as inclusions in garnet. Diamond and coesite are considered to have formed at the peak ultrahigh-pressure metamorphic (UHPM) conditions. Kumdykolite has been proposed to be a metastable phase formed during rapid cooling from high temperature. Moissanite points to extremely reduced conditions during subduction to great depths. The finding of UHP phases in felsic granulites in the Moldanubian Zone is clear evidence for subduction of crustal materials to mantle depths. The garnet hosting the UHP phase inclusions usually preserves prograde compositional zoning; this in combination with the UHPM mineral inclusions suggests that the felsic material should have passed UHP metamorphism at a low-temperature gradient. Isothermal decompression (the commonly accepted model) at temperatures of 850-950 °C would have substantially modified and homogenized the garnet composition eliminating any compositional

  12. Major and trace elements in pyrope almandine garnets as sediment provenance indicators of the Lower Carboniferous Culm sediments, Drahany Uplands, Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Čopjaková, Renata; Sulovský, Petr; Paterson, Bruce A.

    2005-05-01

    The Lower Carboniferous Culm Basin is part of the European Variscan foreland basin. Garnet is an abundant heavy mineral at all stratigraphic levels of the Culm sediments (the Protivanov, Rozstání and Myslejovice Formation from base to top). This paper compares the major element (electron microprobe) and trace element (LA-ICP-MS) compositions of garnet for the purpose of studying the provenance of the Culm sediments. The polymict garnet assemblages ranging from the Protivanov to lower part of the Myslejovice Formation (Goniatite zones Pe γ-Go α) pass into oligomict ones dominated by pyrope-almandine garnets (uppermost part of the Myslejovice Formation; Goniatite zones Go β-Go γ). As the predominant low-grossular pyrope-almandines from oligomict garnet assemblages are very uniform and homogeneous in major element composition, we studied their trace element composition and zoning. Pyrope-almandine garnets are poor in LREE and show enrichment in HREE; the chondrite-normalized patterns are almost flat from Dy to Lu and show a significant negative Eu anomaly, typical for granulite-grade garnets. Major element compositions of detrital low-grossular pyrope-almandines can only be matched with some granulites and garnetiferous felsic gneisses of the Bohemian Massif. Garnets from granulites cropping out at the present-day erosion level of the Bohemian Massif have usually higher Ca and/or lower Mg contents. The major and trace element compositions and zoning patterns of pyrope-almandine garnets from the upper part of the Myslejovice Formation compare well with garnets from the Miroslav granulites and small Moldanubian granulite bodies west of the Třebíč Massif. The Moldanubian granulites are commonly associated with mantle-derived peridotites and eclogites. The presence of detrital Cr-spinels with high Cr# and low Mg# (single grains of Cr-spinels and fine-grained kelyphitic intergrowths of Cr-spinel with chlorite) comparable with spinel types from Moldanubian

  13. NATO granulite conference

    NASA Astrophysics Data System (ADS)

    Vielzeuf, D.; Vidal, Ph.

    On September 5-9, 1988, 83 participants from 20 different countries gathered in Clermont- Ferrand, France, for the workshop Petrology and Geochemistry of Granulites a nd Related Rocks. All geoscience disciplines were represented. The workshop was cosponsored by Universite Blaise Pascal, UFR Scientifique et Technique, Centre National de la Recherche Scientifique, International Lithosphere Program (working Group 2c), IGCP Project 235, Societe Francaise d e Mineralogie, Ministere de l'Education Nationale (DAGIC), Ministere des Affaires Etrangeres (DGSTD), Conseil Regional d Auvergne , Conseil General du Puy de Dome, Mairie de Clermont-Ferrand.

  14. Tectonometamorphic evolution of the Bohemian Massif: evidence from high pressure metamorphic rocks

    NASA Astrophysics Data System (ADS)

    O'Brien, P. J.; Carswell, D. A.

    1993-09-01

    The Variscan orogenic belt, of which the Bohemian Massif is a part, is typically recognized for its characteristic low pressure, high temperature metamorphism and a large volume of granites. However, there are also bodies of high pressure rocks (eclogites, garnet peridotites and high pressure granulites) which are small in size but widely distributed throughtout the Massif. Initially the high pressure rocks were considered to be relicts of a much older orogenic event, but the increasing data derived from isotopic and geochronological investigations show that many of these rocks have Palaeozoic protoliths. Metamorphic ages from the high pressure rocks define no single event. Instead, a number of discrete clusters of ages are found between about 430 Ma and the time of the dominant low pressure event at around 320 330 Ma. Most of the eclogite and granulite facies rocks are assigned to allochthonous nappes that arrived close to the end of the low pressure event, but before final granite intrusion. The nappes contain a mixture of different units and the relationship between rocks with high pressure relicts and host gneisses with no apparent signs of deep burial is still problematic. Some of the high pressure rocks retain evidence of multiple stages of partial re-equilibration during uplift. Moreover, it can be shown in certain instances that host gneisses also endured a multistage metamorphic development but with a peak event convergent with one of the breakdown stages in the enclosed rocks with high pressure relicts. It thus appears that the nappe units are composite bodies probably formed during episodic intracrustal thrusting. Fluids derived from prograde dehydration reactions in the newly under thrusting slab are taken to be the catalysts that drove the partial re-equilibrations. On the scale of the whole Massif it can be seen within the units with high pressure relicts that the temperature at the peak recorded pressure and that during the breakdown are variable in

  15. «Granulite» zircons of the Lapland granulite belt

    NASA Astrophysics Data System (ADS)

    Kaulina, T.

    2003-04-01

    An age of the main stage of granulite metamorphism, which followed the overthrusting of the Lapland granulite belt (LGB) is estimated at about 1.91-1.95 Ga (Tugarinov, Bibikova, 1980; Bernard-Griffiths et al., 1984; Bibikova et al., 1993; Mitrofanov et al., 1993). This high-grade metamorphism is dated by U-Pb method on short prismatic gem-quality zircons that are typical for granulites and are interpreted as formed under stress and space-shortage conditions of the high pressure. And the common belief is that these zircon ages are dating the peak conditions of a metamorphic P-T path, since zircon has a high closure temperature of its U-Pb system. We studied rocks with different degree of metamorphism from Yavr and Pados rivers district (Kola Peninsula, Russia) located in the connection zone of the Tanaelv belt and LGB. Samples from the Tanaelv belt were taken from: 1) leucocratic garnet-clinopyroxene-amphibole plagiogneiss, chemically corresponds to andesite and formed under amphibolite facies 2) leucocratic biotite-pyroxene plagiogneiss with mineral association of granulite facies. Lapland granulites are represented by sillimanite-garnet-biotite gneiss from khondalite complex and leuco-mesocratic amphibole-pyroxene-plagioschist, belonging to the charnockite complex. Metamorphic zircons in all studied samples are represented practically by crystals of the same image. These are round or isometric (rarely subidiomorphic-prismatic in mafic granulites) large crystals with bright luster and high transparency. They are colorless or weakly colored into yellowish-pinkish tones. Crystals are zoneless but may contain cores, especially zircons from khondalite, 60% of which contain zoned cores. Thus typically “granulitic” zircon, described in many works, is the dominant type both in granulites of the Lapland belt and in amphiboles gneisses of the Tanaelv belt. Zircons are distinguished by low U contents (up to 100 ppm) and high Th/U and Zr/Hf ratios (0.6-0.7 and 42

  16. On the formation of granulites

    USGS Publications Warehouse

    Bohlen, S.R.

    1991-01-01

    The tectonic settings for the formation and evolution of regional granulite terranes and the lowermost continental crust can be deduced from pressure-temperature-time (P-T-time) paths and constrained by petrological and geophysical considerations. P-T conditions deduced for regional granulites require transient, average geothermal gradients of greater than 35??C km-1, implying minimum heat flow in excess of 100 mW m-2. Such high heat flow is probably caused by magmatic heating. Tectonic settings wherein such conditions are found include convergent plate margins, continental rifts, hot spots and at the margins of large, deep-seated batholiths. Cooling paths can be constrained by solid-solid and devolatilization equilibria and geophysical modelling. -from Author

  17. Relative strength of lithospheric mantle compared to granulite lower crust in orogenic roots: insight from field laboratory.

    NASA Astrophysics Data System (ADS)

    Kusbach, V.; Ulrich, S.; Schulmann, K.

    2009-04-01

    The continental lithosphere is composed by strong lithospheric mantle and weak lower crust for average and hot geotherms. However, some experiments and seismic studies show that the strength contrast between mantle and crust can vary in order of several magnitudes. The internal zone of the European Variscan orogen (Bohemian Massif, Czech Republic) contains large complexes of Ky - K-feldspar granulites with incorporated spinel and garnet peridotites that can respond to question of mantle-lower crust strength contrast from the field perspective. The studied spinel-garnet harzburgite body (the Mohelno peridotite) represents probably a fragment of strongly depleted oceanic lithosphere showing peak conditions of 22,4-27,6 kbar and 1120-1275°C. The peridotite forms large folded sheet with steep hinge and vertical axial plane. It exhibits presence of spinel along the outer arc and the internal part of the fold and garnet along inner arc, both related to coarse-grained orthopyroxene - olivine microstructure. This coarse microstructure is dynamically recrystallized forming fine-grained matrix (~10 - 20 microns) and the EBSD measurements show presence of axial [100] LPO olivine pattern dominantly along the outer arc of the fold and in spinel harzburgite, while the inner arc of the fold and partly also garnet harzburgite reveals presence of axial [010] LPO pattern. Steep foliation and sub-horizontal to moderately plunging lineation determined from olivine EBSD data defines the shape of the megafold. Host rocks exhibit transposed mylonitic fabric S1-2 revealing peak conditions of 18 kbar, 800°C and heterogeneous D3 retrogression at about 10 - 7 kbar, 650°C. The foliation S2-3 is fully concordant with limbs of peridotite megafold, but close to the outer arc it is affected by asymmetrical folds with axial planar leucosomes coherent with the shape of the megafold hinge zone. In contrast, the S2 in the internal part of the megafold is affected by sinistral and dextral melt

  18. Continental crust subducted deeply into lithospheric mantle: the driving force of Early Carboniferous magmatism in the Variscan collisional orogen (Bohemian Massif)

    NASA Astrophysics Data System (ADS)

    Janoušek, Vojtěch; Schulmann, Karel; Lexa, Ondrej; Holub, František; Franěk, Jan; Vrána, Stanislav

    2014-05-01

    The vigorous Late Devonian-Early Carboniferous plutonic activity in the core of the Bohemian Massif was marked by a transition from normal-K calc-alkaline, arc-related (~375-355 Ma), through high-K calc-alkaline (~346 Ma) to (ultra-)potassic (343-335 Ma) suites, the latter associated with mainly felsic HP granulites enclosing Grt/Spl mantle peridotite bodies. The changing chemistry, especially an increase in K2O/Na2O and 87Sr/86Sri with decrease in 143Nd/144Ndi in the basic end-members, cannot be reconciled by contamination during ascent. Instead it has to reflect the character of the mantle sources, changing over time. The tectonic model invokes an oceanic subduction passing to subduction of the attenuated Saxothuringian crust under the rifted Gondwana margin (Teplá-Barrandian and Moldanubian domains). The deep burial of this mostly refractory felsic metaigneous material is evidenced by the presence of coesite/diamond (Massonne 2001; Kotková et al. 2011) in the detached UHP slices exhumed through the subduction channel and thrusted over the Saxothuringian basement, and by the abundance of felsic HP granulites (> 2.3 GPa), some bearing evidence for small-scale HP melt separation, in the orogen's core (Vrána et al. 2013). The subduction channel was most likely formed by 'dirty' serpentinites contaminated by the melts/fluids derived from the underlying continental-crust slab (Zheng 2012). Upon the passage through the orogenic mantle, the continental crust-slab derived material not only contaminated the adjacent mantle forming small bodies/veins of pyroxenites (Becker 1996), glimmerites (Becker et al. 1999) or even phlogopite- and apatite-bearing peridotites (Naemura et al. 2009) but the felsic HP-HT granulites also sampled the individual peridotite types at various levels. Eventually the subducted felsic material would form an (U)HP continental wedge under the forearc/arc region, to be later redistributed under the Moldanubian crust by channel flow and crustal

  19. Heat transfer by fluids in granulite metamorphism

    NASA Technical Reports Server (NTRS)

    Morgan, Paul; Ashwal, Lewis D.

    1988-01-01

    The thermal role of fluids in granulite metamorphism was presented. It was shown that for granulites to be formed in the middle crust, heat must be advected by either magma or by volatile fluids, such as water or CO2. Models of channelized fluid flow indicate that there is little thermal difference between channelized and pervasive fluid flow, for the same total fluid flux, unless the channel spacing is of the same order or greater than the thickness of the layer through which the fluids flow. The volumes of volatile fluids required are very large and are only likely to be found associated with dehydration of a subducting slab, if volatile fluids are the sole heat source for granulite metamorphism.

  20. Granulites from Northwest Indian Shield: Their differences and similarities with Southern Indian granulite terrain

    NASA Technical Reports Server (NTRS)

    Sharma, R. S.

    1988-01-01

    Granulite facies suite in the NW Indian Shield is exposed at Sand Mata, Udaipur district, Rajasthan, as an oval-shaped massif within amphibolite facies rocks of the Banded Gneissic Complex (3.5 to 2.6 b.y. old) - a possible analogue of the Peninsular gneiss of Dharwar craton. On the basis of quantitative P-T estimates, combined with the textural evidence for the crystallization sequence of the Al-silicate polymorphs (kyanite to sillimanite to kyanite) in the pelitic granulite, the deduced P-T path for the Sand Mata granulites is the reverse of that characterizing the Plate tectonic collision zone. It, however, agrees with the P-T path inferred in the case of the southern Indian granulitic rocks.

  1. Two types of ultrapotassic plutonic rocks in the Bohemian Massif — Coeval intrusions at different crustal levels

    NASA Astrophysics Data System (ADS)

    Kotková, Jana; Schaltegger, Urs; Leichmann, Jaromír

    2010-03-01

    We present U-Pb zircon age determinations of two Variscan ultrapotassic plutonic rocks from the Moldanubian Zone (Bohemian Massif). Equant, multifaceted zircons without inherited cores from a two-pyroxene-biotite quartz monzonite of the Jihlava Pluton yielded a precise age of 335.12 ± 0.57 Ma, interpreted as dating magma crystallization. The majority of both tabular and prismatic grains from the amphibole-biotite melagranite ("durbachite") from the Třebíč Pluton plot along a discordia intersecting the concordia at 334.8 ± 3.2 Ma; prismatic zircon grains commonly contain inherited cores and yield an upper intercept age of 2.2 Ga, indicating early Proterozoic inheritance. We therefore suggest that both types of the ultrapotassic plutonic rocks from the Bohemian Massif crystallized at ca 335 Ma, and the previously published ages higher than ca 340 Ma for "durbachites" were biased by a small amount of unresolved inheritance. The ultrapotassic magma emplacement in the middle crust was related to rapid exhumation of a deep crustal segment, considered as isothermal decompression between high-pressure (˜ 340 Ma) and medium-pressure (˜ 333 Ma) stages recorded in granulites. Mineral assemblages as well as external and internal zircon morphology suggest that the Jihlava intrusion was deep and dry, whereas the Třebíč intrusion was shallow and wet. Low ɛHf values of zircons (- 4.4 to - 7.5) in both rock types suggest a similar source with a predominant crustal component. However, inherited grains in the Třebíč melagranite indicate its contamination with crustal material during emplacement, and thus possibly a slower rate of exhumation and/or of magma ascent through the crust.

  2. Petrology and geochemistry of the high-pressure Nilgiri Granulite Terrane, Southern India

    NASA Technical Reports Server (NTRS)

    Srikantappa, C.; Ashamanjari, K. G.; Raith, M.

    1988-01-01

    The Nilgiri granulite terrane in Southern India is predominantly composed of late Archaean medium- to coarse-grained enderbitic to charnockitic rocks. The dominant regional foliation strikes N60 to 70E with generally steep dips. Tight minor isoclinal folds have been observed in places. Granoblastic polygonal micro-structures are common and indicate thorough post-kinematic textural and chemical equilibration at conditions of the granulite facies (2.5 Ga ago). Late compressional deformation in connection with the formation of the Moyar and Bhavani shear zones to the north and south of the Nilgiri block, resulted in wide-spread development of weakly to strongly strained fabrics and was accompanied by minor rehydration. Enderbites and charnockites range from tonalitic to granodioritic in composition. A magmatogenic origin of the protoliths is inferred from their chemical characteristics which resemble those of the andesitic to dacitic members of Cordillera-type calc-alkaline igneous suites. A significant lithological feature of the Nilgiri granulite terrane are numerous extended bodies, lenses and pods of gabbroic and pyroxenitic rocks which are aligned conformable to the foliation of the enderbite-charnockite complex and which have also been deformed and metamorphosed at granulite facies conditions.

  3. Mineralogy and cooling history of magnesian lunar granulite 67415

    NASA Technical Reports Server (NTRS)

    Takeda, Hiroshi; Miyamoto, Masamichi

    1993-01-01

    Apollo granulite 67415 was investigated by mineralogical techniques to gain better understanding of cooling histories of lunar granulities. Cooling rates were estimated from chemical zoning of olivines in magnesian granulitic clasts by computer simulation of diffusion processes. The cooling rate of 10 deg C/yr obtained is compatible with a model of the granulite formation, in which the impact deposit was cooled from high temperature or annealed, at the depth of about 25 m beneath the surface.

  4. Prograde Metamorphism recorded in Antarctic Granulite

    NASA Astrophysics Data System (ADS)

    Marschall, H.; Pauly, J.; Chatterjee, N.; Monteleone, B.; Meyer, H. P.

    2015-12-01

    High-grade metamorphic rocks provide an archive of tectonic processes and record conditions in the deep roots of orogenic belts. Granulites typically preserve chemical and mineralogical evidence of the peak temperature to which crustal rocks may be subjected, and they commonly preserve a multitude of textural and chemical features that allow a rather detailed reconstruction of their cooling and exhumation. More rarely, however, is it possible to reconstruct parts of the prograde path, which would allow a reconstruction of the loading and heating of the rocks. Access to the prograde P-T path and the rates and durations involved in granulite formation would provide important constraints on the convergence part of orogenic processes. Here we investigated a sample of felsic granulite from the H.U. Sverdrupfjella, which is part of the high-grade Maud Belt (East Antarctica). Peak-metamorphic conditions of approximately 925 °C and 1.45 GPa persisted for a maximum of circa 14 million years and were attained shortly after 570 Ma. In addition to the short-lived temperature peak, zircon preserved evidence for protracted granulite facies conditions with temperatures above 800 °C persisting for approximately 40 million years. Constraints on prograde metamorphism are recorded by garnet that preserved pre-peak metamorphic growth zones, by Ti zonation in zircon and by rutile inclusions in garnet. Zr-in-rutile thermometry using rutile included in different generations of garnet is used to reconstruct the prograde P-T path documenting burial followed by heating to ultra-high temperatures at peak pressures. Complementary, Ti zonation in prograde cores of zircon grains document and date heating, whereas younger zircon rims show again lower Ti-in-zircon temperatures and date the retrograde stages of metamorphism. The highest T is recorded in rutile, but not in zircon, consistent with the dissolution rather than growth of zircon at ultra-high temperatures. The clockwise loading

  5. Horizontal Strain Field for the Bohemian Massif, Central Europe

    NASA Astrophysics Data System (ADS)

    Schenk, V.; Pichl, R.; Schenkova, Z.; Marek, T.

    2010-12-01

    The horizontal strain field of the Bohemian Massif, central Europe, was assessed from GNSS data monitored on permanent stations of the Geodynamic Network of the Academy of Science of the Czech Republic (GEONAS) and of the Czech Office for Surveying, Mapping and Cadastre (CZEPOS). For every area a representative motion velocity was determined. Their comparison with general motions of the Eurasian plate ascertained by the NNR-NUVEL-1A model gave deviations characterizing recent influence of the Alps to the northern geological units, in our case the Bohemian Massif. From these motions a regional pattern of the horizontal strain field for the Bohemian Massif had been calculated. It was found that (i) the northern part of the Massif is under dominant E-W extensions and (ii) slight contractions were detected for the NNE-SSW direction in eastern regions of the Massif. Obtained results will be presented and discussed from a viewpoint of the Alpine structural unit actions to surrounding geological units.

  6. Generation of Granulites Constrained by Thermal Modeling

    NASA Astrophysics Data System (ADS)

    Depine, G. V.; Andronicos, C. L.; Phipps-Morgan, J.

    2006-12-01

    The heat source needed to generate granulites facies metamorphism is still an unsolved problem in geology. There is a close spatial relationship between granulite terrains and extensive silicic plutonism, suggesting heat advection by melts is critical to their formation. To investigate the role of heat advection by melt in the generation of granulites we use numerical 1-D models which include the movement of melt from the base of the crust to the middle crust. The model is in part constrained by petrological observations from the Coast Plutonic Complex (CPC) in British Columbia, Canada at ~ 54° N where migmatite and granulite are widespread. The model takes into account time dependent heat conduction and advection of melts generated at the base of the crust. The model starts with a crust of 55 km, consistent with petrologic and geochemical data from the CPC. The lower crust is assumed to be amphibolite in composition, consistent with seismologic and geochemical constraints for the CPC. An initial geothermal gradient estimated from metamorphic P-T-t paths in this region is ~37°C/km, hotter than normal geothermal gradients. The parameters used for the model are a coefficient of thermal conductivity of 2.5 W/m°C, a density for the crust of 2700 kg/m3 and a heat capacity of 1170 J/Kg°C. Using the above starting conditions, a temperature of 1250°C is assumed for the mantle below 55 km, equivalent to placing asthenosphere in contact with the base of the crust to simulate delamination, basaltic underplating and/or asthenospheric exposure by a sudden steepening of slab. This condition at 55 km results in melting the amphibolite in the lower crust. Once a melt fraction of 10% is reached the melt is allowed to migrate to a depth of 13 km, while material at 13 km is displaced downwards to replace the ascending melts. The steady-state profile has a very steep geothermal gradient of more than 50°C/km from the surface to 13 km, consistent with the generation of andalusite

  7. CO2-rich fluid inclusions in greenschists, migmatites, granulites, and hydrated granulites

    NASA Technical Reports Server (NTRS)

    Hollister, L. S.

    1988-01-01

    Data was discussed from several different terrains in which CO2-rich fluid inclusions occur despite parageneses that predict the presence of H2O-rich fluids. CO2-rich fluid inclusions, some having densities appropriate for peak-metamorphic conditions, were found in greenschists, amphibolites, migmatites, and hydrated granulites. The author suggested that there may be a common process that leads to CO2-rich secondary inclusions in metamorphic rocks.

  8. Carbonic metamorphism, granulites and crustal growth

    NASA Technical Reports Server (NTRS)

    Newton, R. C.; Smith, J. V.; Windley, B. F.

    1980-01-01

    Stabilization of early crust against melting by high radioactivity and against resorption into the mantle by fast convective overturn requires that water and heat producers were flushed upwards within 50 Myr of accretion. Creation of a refractory base of granulite by metamorphism associated with CO2 vapour explains CO2-rich fluid inclusions in ancient high-grade rocks, minor-element depletions and local phenomena of arrested development of charnockite in Precambrian terrains. The hot-spot and plate-tectonic models of Precambrian crustal evolution lead to different schemes for CO2 delivery to continental roots. New tectonic concepts may be needed to explain carbonic metamorphism and other features of early crustal evolution.

  9. Hot granulite nappes — Tectonic styles and thermal evolution of the Proterozoic granulite belts in East Africa

    NASA Astrophysics Data System (ADS)

    Fritz, Harald; Tenczer, Veronika; Hauzenberger, Christoph; Wallbrecher, Eckart; Muhongo, Sospeter

    2009-11-01

    A section through the Neoproterozoic Mozambique Belt of Tanzania exposes western foreland (Archaean Tanzania Craton and Palaeoproterozoic Usagaran Belt), marginal (Western Granulites) and eastern, internal (Eastern Granulites) portions of the orogen. The assembly of granulite nappes at ca. 620 Ma displays westward emplacement along an eastward deepening basal decollement and forward propagation of thrusts, climbing from the deep crust to the surface. This goes along with eastward increase of syntectonic temperatures, derived from prevalent deformation mechanisms, and eastward decrease of the kinematic vorticity number. Distinctly different pressure - temperature paths with a branch of isothermal decompression (ITD) in Western Granulites and isobaric cooling (IBC) in Eastern Granulites reflect residence times of rocks within lower crustal levels. Western Granulites, exhumed rapidly at the orogen margin, display ITD and non-coaxial fabrics. Eastern Granulites in the internal orogen portions escaped from rapid exhumation and show IBC and co-axial flow fabrics. The vertical variation of structural elements, i.e. basement — cover relations within the Eastern Granulites, shows decoupling between lower and middle crust with horizontal west — east stretching in the basement and horizontal west — east shortening in the cover. A model of hot fold nappes [Beaumont, C., Nguyen, M.H., Jamieson, R.A., Ellis, S., 2006. Crustal flow modes in large hot orogens. In: Law, R.D., Searle, M.P., Godin, L., (eds). Channel Flow, Ductile Extrusion and Exhumation in Continental Collision Zones. Geological Society, London, Special Publications. vol. 268, 91-145] is adopted to explain flow diversity in the deep crust. The lower crust represented by Eastern Granulite basement flowed coaxially outwards (westward) in response to thickened crust and elevated gravitational forces, supported by a melt-weakened, viscous channel at the crustal base. Horizontal flow with rates faster than thermal

  10. Petrogenesis of Variscan lamproites of the Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Krmíček, Lukáš; Romer, Rolf L.; Glodny, Johannes

    2015-04-01

    Paleozoic convergence of Laurussia and Gondwana-derived terranes with subduction of oceanic and continental crust of various compositions metasomatized the local mantle, a process which eventually led to a highly heterogeneous lithospheric mantle beneath the European Variscides. The eastern termination of the European Variscides (Moldanubian and Saxo-Thuringian zones of the Bohemian Massif in the Czech Republic, Austria, Germany, and Poland) is unusual as within a small area, the mantle had been modified by material from several subduction zones. Along the eastern border of the Bohemian Massif, mantle-derived dyke intrusions of peralkaline, perpotassic, and ultrapotassic compositions occur. The rocks are distinguished by mineral associations with K-amphibole and Fe-microcline and correspond mineralogically to a new variety of silica-rich lamproites. Lamproites from the Moldanubian Zone contain characteristic Ba-Ti-Zr accessory minerals (e.g., baotite, benitoite, hollandite), whereas lamproites from the Saxo-Thuringian Zone lack these minerals. Variscan lamproites from the Bohemian Massif sampled lithospheric mantle, whose chemical signature reflects extreme depletion (low CaO and Al2O3 contents) followed by strong metasomatic enrichment by material released from the subducted rocks, giving rise to crust-like trace element pattern, variably radiogenic Sr and unradiogenic Nd isotopic compositions, crustal Pb isotopic compositions, and a wide range of δ7Li ratios ranging from markedly positive to highly negative values. The metasomatic component is variably prominent in the lamproites, depending on the extent of partial melting, and the nature of the source of the metasomatic component. Preferential melting of the metasomatically enriched lithospheric mantle with stable K-amphibole resulted in lamproitic melts with very negative δ7Li values, which correlate positively with the peralkalinity, HFSE contents, and lower ɛNd of these rocks. Both, higher degree of

  11. Adakites—the key to understanding LILE depletion in granulites

    NASA Astrophysics Data System (ADS)

    Rollinson, Hugh R.; Tarney, John

    2005-01-01

    For more than 20 years, it has been argued that granulites of the lower continental crust are depleted in fluid-mobile elements such as Cs, Rb, U and Th, either because they were removed by melting of the lower crust or through dehydration. We argue that there is little evidence for a simple relationship between granulite-facies metamorphism and element depletion, and propose that, for felsic orthogneisses, the depletion may be a primary feature of crust generation processes. Modern adakites show a range of fluid-mobile element ratios and adakites from the Austral Volcanic Zone (AVZ), Chile show fluid-mobile element ratios very similar to those found in lower crustal felsic granulites. This suite of adakites has a strong slab-derived component. We propose that modern adakites of the type found in the Austral Volcanic Zone are analogous, in their genesis, to lower crustal felsic granulites and that their mafic precursors were already depleted in fluid-mobile trace elements, prior to melting. An incremental melting model, in which fluid-mobile elements are released from an eclogitic slab prior to partial melting, can explain the fluid-mobile element behaviour of both modern adakites and lower crustal felsic granulites.

  12. Granulites: Melts and fluids in the deep crust

    NASA Technical Reports Server (NTRS)

    Valley, John W.

    1988-01-01

    Known examples of granulite facies metamorphism span at least 3.5 by. of Earth history. Mineralogic geobarometry indicates that such metamorphism has occurred in the deep crust, typically at 20 to 30 km (6 to 9 kbar). Geothermometry indicates that peak T = 700 to 900 C and therefore that T was elevated by at least 200 C over an anorgenic geotherm of 15 to 20 C/km. Commonly invoked sources of heat include rising magmas, radioactive decay insulated by continent/continent collision, mantle volatiles, or crustal thinning. Present day crustal thicknesses are normal beneath exposed granulite terranes and the common absence of evidence for post-metamorphic underplating suggests synmetamorphic thicknesses of 60 to 80 km. Thus granulites form in tectonically active regions of thickened crust and elevated geotherm. Xenolith suites suggest that granulite facies mineralogy persists in the deepest crust after tectonism in spite of declining temperature to greenschist/amphibolite facies conditions. The relative proportions of granulite terranes that are formed by Adirondack-type metamorphism dominantly magmatic/fluid-absent), India-type metamorphism (CO2 saturated), or some combination of 1 and 2 remains an important tectonic question.

  13. Nature and origin of fluids in granulite facies metamorphism

    NASA Technical Reports Server (NTRS)

    Newton, R. C.

    1988-01-01

    The various models for the nature and origin of fluids in granulite facies metamorphism were summarized. Field and petrologic evidence exists for both fluid-absent and fluid-present deep crustal metamorphism. The South Indian granulite province is often cited as a fluid-rich example. The fluids must have been low in H2O and thus high in CO2. Deep crustal and subcrustal sources of CO2 are as yet unproven possibilities. There is much recent discussion of the possible ways in which deep crustal melts and fluids could have interacted in granulite metamorphism. Possible explanations for the characteristically low activity of H2O associated with granulite terranes were discussed. Granulites of the Adirondacks, New York, show evidence for vapor-absent conditions, and thus appear different from those of South India, for which CO2 streaming was proposed. Several features, such as the presence of high-density CO2 fluid inclusions, that may be misleading as evidence for CO2-saturated conditions during metamorphism, were discussed.

  14. The timing and mechanism of depletion in Lewisian granulites

    NASA Technical Reports Server (NTRS)

    Cohen, A. S.; Onions, R. K.; Ohara, M. J.

    1988-01-01

    Large Ion Lithophile (LIL) depletion in Lewisian granulites is discussed. Severe depletions in U, Th, and other LIL have been well documented in Lewisan mafic and felsic gneisses, but new Pb isotopic analyses show little or no depletion in lithologies with high solidus temperatures, such as peridotite. This suggests that LIL transport in this terrane took place by removal of partial melts rather than by pervasive flooding with externally derived CO2. The Pb and Nd isotopic data gathered on these rocks show that the depletion and granulite metamorphism are distinct events about 250 Ma apart. Both fluid inclusions and cation exchange geothermometers date from the later metamorphic event and therefore have little bearing on the depletion event, suggesting a note of caution for interpretations of other granulite terranes.

  15. Granulite Facies Metamorphism in the Kabul Block, Afghanistan

    NASA Astrophysics Data System (ADS)

    Collett, S.; Faryad, S. W.

    2012-04-01

    The Proterozoic Kabul Block is part of the Afghan Central Massif and occurs between the Hindu Kush and Sulaiman Mountain ranges. It consists of amphibolite to granulite facies rocks of Paleo-Neoproterzoic age. The Kabul block has a lens-like shape and is encircled by the Chaman fault from NW and the Altimoor faults from SE. The basement rocks of the Kabul Block are predominantly represented by schists, gneisses and migmatites with lenses of amphibolites and locally also marble. They are mostly unconformably overlain by low-grade early to late Paleozoic sequences. As the Kabul block occurs between the magmatic arc and accretionary wedge which formed during subduction and subsequent collision of the Indian Plate beneath the Laurasian continent, it was subjected to compression and a metamorphic overprint during Alpine orogeny to various degrees. The granulite facies rocks are exposed only locally within amphibolite facies gneisses and migmatites, exposed in the hills that surround Kabul city. They are represented by quartz-feldspathic lithology, which contains lenses of marble and amphibolite. Granulite facies conditions are confirmed by the presence of orthopyroxene both in the gneiss and amphibolite. In addition to orthopyroxene (XMg = 0.4, Al2O3 = 1.3 wt %), the gneiss contains quartz, plagioclase (An27-36), orthoclase and biotite with XMg = 0.36 and TiO2 = 3.5 wt %. The rocks are overprinted by amphibolite facies metamorphism, which is represented by the formation of garnet overgrowing biotite and orthopyroxene. The mafic rocks consist of plagioclase (An87), hornblende (XMg = 0.81), biotite and orthopyroxene (XMg = 0.57, Al2O3 = 1.1 wt %) with inclusions of ilmenite, cummingtonite (XMg = 0.6) and biotite. Hornblende forms as a rim around cummingtonite and overgrows orthopyroxene. Biotite present in this sample has XMg = 0.63 with almost 4 wt % TiO2. Marble adjacent to the granulites are mostly pure calcite, but at contact with surrounding rocks may contain also

  16. Petrogenetic grids for sapphirine-bearing granulites

    NASA Astrophysics Data System (ADS)

    Podlesskii, Konstantin K.

    2010-05-01

    Phase relations involving sapphirine, garnet, spinel, orthopyroxene, olivine, cordierite, alumina silicates, corundum, and quartz have been calculated in the system FeO-MgO-Al2O3-SiO2 based on internally consitent thermodynamic properties of both the end-member minerals and the solid solutions (Gerya et al., 2004; Podlesskii et al., 2008). The derived P-T diagrams imply stable invariant points and stability fields of key assemblages that differ from those proposed by other authors (Kelsey et al., 2004; Harley 2008). The sapphirine + quartz assemblage, which is widely recognized as indicative of ultrahigh-temperature metamorphism, can be stable down to 835° C and ~6 kbar. The sapphirine + kyanite assemblage has been found stable at temperatures below 860° C and 11.3 kbar, whereas the sapphirine + forsterite assemblage may be stable below 800° C only under specific conditions of a very low activity of water. The existing constraints on the thermodynamic properties of sapphirine are considered insufficient to make decisive conclusions about metamorphic conditions. Granulites containing the sapphirine + quartz assemblage have been investigated with the microprobe to apply both the conventional thermobarometry and thermometry based on Ti contents of quartz (TitaniQ, Wark & Watson, 2006). The results demonstrate that, in some cases, this assemblage might have formed at relatively low temperatures during retrograde stages of metamorphism. The research has been supported by the RFBR grant 09-05-00193. References Gerya,T.V., Perchuk,L.L., & Podlesskii,K.K. In: Zharikov,V.A. & Fed'kin,V.V. (eds.) Experimental Mineralogy: Some Results on the Century's Frontier. Moscow: Nauka, Vol. 2, 188-206 (2004). Harley,S.L. Refining the P-T records of UHT crustal metamorphism. Journal of Metamorphic Geology, 26, 125-154 (2008). Kelsey,D.E., White,R.W., Holland,T.J.B., & Powell,R. Journal of Metamorphic Geology, 22, 559-578 (2004). Podlesskii,K.K., Aranovich,L.Y., Gerya

  17. The Curious Case of the Lunar Magnesian Granulitic Breccias

    NASA Technical Reports Server (NTRS)

    Korotev, R. L.; Jolliff, B. L.

    2001-01-01

    Magnesian granulitic breccias have high Th/Sm ratios, they are not related to Mg-suite plutonic rocks in any straightforward manner, and they may have an igneous rock precursor that is not yet recognized among our samples of the Moon. Additional information is contained in the original extended abstract.

  18. Documentation and evaluation of slope instabilities and other geological phenomena in the Geopark Bohemian Paradise (Czech Republic)

    NASA Astrophysics Data System (ADS)

    Krejčí, Oldřich; Krejčí, Vladimíra; Švábenická, Lilian; Hartvich, Filip

    2016-04-01

    Geographically, the area is part of the Bohemian Cretaceous Basin, the unit Jičín Hilly land. Since October 2005, the area belongs to the European Geopark UNESCO Bohemian Paradise. The reason of the protection is a major complex of rocks, natural forest communities and geomorphological valuable territory. The territory has been newly geologically mapped in a scale of 1 : 25,000. Sediments of the Czech Cretaceous Basin covers an area of 181 km2 and were deposited transgressively on the Permian - Carboniferous and crystalline basement of the Bohemian Massif. Except for locally developed basal sediments of fluvial origin they are mostly shallow marine sediments. Middle Turonian to Lower Coniacian rocks of the Jizera lithofacies are dominant by calcareous sandstones deposited under extremely dynamic conditions. Scattered alkaline volcanics penetrate the older formations as small intrusions and form locally preserved bodies at the surface. Area is strongly predisposed to the development of various types of landforms by structural segmentation of the Cretaceous sandstones and claystones and by Plio-Pleistocene inverse erosion. Numerous archival manuscripts are available from this area together with published geological, engineering-geological, geomorphological and historical papers. This is due to the fact that in 1926 a large landslide destroyed a substantial part of the village Dneboh, situated on the slope below a rock castle Drabske Svetnicky. Drabske Svetnicky is a ruin of a 13th century castle. It is located on the ragged edge of a sandstone cliff high above surrounding landscape. The castle covers a group of seven sandstone rocks, connected with wooden bridges. In the 50ies of the 20th century, an increased attention was paid to Drabske Svetnicky by experts on medieval architecture and a restoration of the original state of the castle rock was accomplished. Remnants of pottery and other findings suggest that the plateau region of the castle was first inhabited

  19. Bohemian circular structure, Czechoslovakia: Search for the impact evidence

    NASA Technical Reports Server (NTRS)

    Rajlich, Petr

    1992-01-01

    Test of the impact hypothesis for the origin of the circular, 260-km-diameter structure of the Bohemian Massif led to the discovery of glasses and breccias in the Upper Proterozoic sequence that can be compared to autogeneous breccias of larger craters. The black recrystallized glass contains small exsolution crystals of albite-oligoclase and biotite, regularly dispersed in the matrix recrystallized to quartz. The occurrence of these rocks is limited to a 1-sq-km area. It is directly underlain by the breccia of the pelitic and silty rocks cemented by the melted matrix, found on several tens of square kilometers. The melt has the same chemistry as rock fragments in major and in trace elements. It is slightly impoverished in water. The proportion of melted rocks to fragments varies from 1:5 to 10:1. The mineralogy of melt viens is the function of later, mostly contact metamorphism. On the contact of granitic plutons it abounds on sillimanite, cordierite, and small bullets of ilmenite. Immediately on the contact with syenodiorites it contains garnets. The metamorphism of the impact rock melt seems the most probable explanation of the mineralogy and the dry total fusion of rocks accompanied by the strong fragmentation. Other aspects of this investigation are discussed.

  20. Cl-rich minerals in Archean granulite facies ironstones from the Beartooth Mountains, Montana, USA: Implications for fluids involved in granulite metamorphism

    NASA Technical Reports Server (NTRS)

    Henry, D. J.

    1988-01-01

    The implications of Cl-rich minerals in granulite facies rocks are discussed. Results from ironstones of the Beartooth Mountains, Montana are discussed. It is suggested that CO2-brine immiscibility might be applicable to granulite facies conditions, and if so, then aqueous brines might be preferentially adsorbed onto mineral surfaces relative to CO2.

  1. A Treasure Chest of Nanogranites: the Bohemian Massif (Central Europe)

    NASA Astrophysics Data System (ADS)

    Ferrero, S.; O'Brien, P. J.; Walczak, K.; Wunder, B.; Ziemann, M. A.; Hecht, L.

    2014-12-01

    Despite 150 years of investigation of the Bohemian Massif (Central Europe), it is only recently that the investigation of old and new samples displayed the occurrence of tiny portions of crystallized anatectic melt in regional migmatites. These vestiges of magma, called "nanogranites", are natural probes of the partial melting processes in the crust. Original melt composition and water content can be directly analyzed after piston cylinder re-homogenization. When compared to classic re-melting experiments, nanogranites are ideal "natural" experimental charges of anatectic melt. They are encapsulated in peritectic garnet immediately after production - both phases are products of the same partial melting reaction. Sheltered inside garnet, they remain unaffected by the physico-chemical changes which affected the host migmatites during their slow cooling, unlike leucosomes and anatexis-related plutons. Five different case studies of nanogranite-bearing high-grade rocks have been identified so far: three in metapelites from the Moldanubian Zone, and two in metagranitoids from the Granulitgebirge and Orlica-Śnieżnik Dome. Their characterization provides insights into how the continental crust melts at different depths, from shallow levels to mantle depths, during different moments of its metamorphic history (prograde vs. decompressional melting). For example, the investigation and experimental re-melting of nanogranites from Grt+Ky leucogranulites (Orlica-Śnieżnik Dome) recently provided evidence of prograde melting of metagranitoids under eclogite-facies conditions (T≥875°C and P~2.7 GPa), close to the stability field of coesite. The melt generated is granitic, hydrous (6 wt% H2O) and metaluminous (ASI=1.03), and is at the moment the "deepest" glass obtained through re-homogenization of primary polycrystalline inclusions in natural rocks. This work confirms that nanogranites in migmatites 1) are a powerful tool to constrain anatexis in natural rocks, and 2) can

  2. Post-granulite facies fluid infiltration in the Adirondack Mountains

    SciTech Connect

    Morrison, J.; Valley, J.W.

    1988-06-01

    Granulite facies lithologies from the Adirondack Mountains of New York contain alteration assemblages composed dominantly of calcite +/- chlorite +/- sericite. These assemblages document fluid infiltration at middle to upper crustal levels. Cathodoluminescence of samples from the Marcy anorthosite massif indicates that the late fluid infiltration is more widespread than initially indicated by transmitted-light petrography alone. Samples that appear unaltered in transmitted light show extensive anastomosing veins of calcite (< 0.05 mm wide) along grain boundaries, in crosscutting fractures, and along mineral cleavages. The presence of the retrograde calcite documents paleopermeability in crystalline rocks and is related to the formation of high-density CO/sub 2/-rich fluid inclusions. Recognition of this process has important implications for studies of granulite genesis and the geophysical properties of the crust.

  3. Origin of granulite terranes and the formation of the lowermost continental crust.

    PubMed

    Bohlen, S R; Mezger, K

    1989-04-21

    Differences in composition and pressures of equilibration between exposed, regional granulite terranes and suites of granulite xenoliths of crustal origin indicate that granulite terranes do not represent exhumed lowermost crust, as had been thought, but rather middle and lower-middle crustal levels. Application of well-calibrated barometers indicate that exposed granulites record equilibration pressures of 0.6 to 0.8 gigapascal (20 to 30 kilometers depth of burial), whereas granulite xenoliths, which also tend to be more mafic, record pressures of at least 1.0 to 1.5 gigapascals (35 to 50 kilometers depth of burial). Thickening of the crust by the crystallization of mafic magmas at the crust-mantle boundary may account for both the formation of regional granulite terranes at shallower depths and the formation of deep-seated mafic crust represented by many xenolith suites.

  4. Origin of granulite terranes and the formation of the lowermost continental crust

    USGS Publications Warehouse

    Bohlen, S.R.; Mezger, K.

    1989-01-01

    Differences in composition and pressures of equilibration between exposed, regional granulite terranes and suites of granulite xenoliths of crustal origin indicate that granulite terranes do not represent exhumed lowermost crust, as had been thought, but rather middle and lower-middle crustal levels. Application of well-calibrated barometers indicate that exposed granulites record equilibration pressures of 0.6 to 0.8 gigapascal (20 to 30 kilometers depth of burial), whereas granulite xenoliths, which also tend to be more mafic, record pressures of at least 1.0 to 1.5 gigapascals (35 to 50 kilometers depth of burial). Thickening of the crust by the crystalliztion of mafic magmas at the crust-mantle boundary may account for both the formation of regional granulite terranes at shallower depths and the formation of deep-seated mafic crust represented by many xenolith suites.

  5. Origin of granulite terranes and the formation of the lowermost continental crust.

    PubMed

    Bohlen, S R; Mezger, K

    1989-04-21

    Differences in composition and pressures of equilibration between exposed, regional granulite terranes and suites of granulite xenoliths of crustal origin indicate that granulite terranes do not represent exhumed lowermost crust, as had been thought, but rather middle and lower-middle crustal levels. Application of well-calibrated barometers indicate that exposed granulites record equilibration pressures of 0.6 to 0.8 gigapascal (20 to 30 kilometers depth of burial), whereas granulite xenoliths, which also tend to be more mafic, record pressures of at least 1.0 to 1.5 gigapascals (35 to 50 kilometers depth of burial). Thickening of the crust by the crystallization of mafic magmas at the crust-mantle boundary may account for both the formation of regional granulite terranes at shallower depths and the formation of deep-seated mafic crust represented by many xenolith suites. PMID:17738304

  6. Magnetism of the Lower Crust: Observations from the Athabasca Granulite Terrain, Northern Canada

    NASA Astrophysics Data System (ADS)

    Brown, L. L.; Williams, M. L.; Seaman, S. J.; Regan, S.; Webber, J.; Orlandini, O. F.

    2012-12-01

    granulites rich with oxide (magnetite) layers. NRM values also show considerable variability, from 1 mA/m to 10 A/m, with the weakest magnetization found in many of the Chipman mafic dikes, intruding across the AGT at ~1.9 Ga, and in granite bodies both in the east and west. The magnetite layers in the mafic granulites are readily identified on ground magnetic traverses. Q values (Koenigsberger ratios) indicate that nearly 30% of the samples measured (N=66) have remanent magnetization greater than induced magnetization. Hysteresis and low temperature measurements identify PSD (pseudo-single domain) magnetite as the predominant oxide; pyrrhotite is also present in a number of samples. In this section of lower crust the high anomalies are directly related to zones of mafic granulite riddled with magnetite layers; the lower anomalies reflect rocks very low in, or even devoid of, magnetic material.

  7. Retrograde fluids in granulites: Stable isotope evidence of fluid migration

    SciTech Connect

    Morrison, J. ); Valley, J.W. )

    1991-07-01

    Widespread retrograde alteration assemblages document the migration of mixed H{sub 2}O-CO{sub 2} fluids into granulite facies rocks in the Adirondack Mountains. Fluid migration is manifest by (1) veins and patchy intergrowths of chlorite {plus minus} sericite {plus minus} calcite, (2) small veins of calcite, many only identifiable by cathodoluminescence, and (3) high-density, CO{sub 2}-rich or mixed H{sub 2}O-CO{sub 2} fluid inclusions. The distinct and varied textural occurrences of the alteration minerals indicate that fluid-rock ratios were low and variable on a local scale. Stable isotope ratios of C, O, and S have been determined in retrograde minerals from samples of the Marcy anorthosite massif and adjacent granitic gneisses (charnockites). Retrograde calcite in the anorthosite has a relatively small range in both {delta}{sup 18}O{sub SMOW} and {delta}{sup 13}C{sub PDB} (8.6 to 14.9% and {minus}4.1 to 0.4%, respectively), probably indicating that the hydrothermal fluids that precipitated the calcite had exchanged with a variety of crustal lithologies including marbles and orthogneisses, and that calcite was precipitated over a relatively narrow temperature interval. Values of {delta}{sup 34}S{sub CDT} that range from 2.8 to 8.3% within the anorthosite can also be interpreted to reflect exchange between orthogneisses and metasediments. The recognition of retrograde fluid migration is particularly significant in granulite facies terranes because the controversy surrounding the origin of granulites arises in part from differing interpretations of fluid inclusion data, specifically, the timing of entrapment of high-density, CO{sub 2}-rich inclusions. Results indicate that retrograde fluid migration, which in some samples may leave only cryptic petrographic evidence, is a process capable of producing high-density, CO{sub 2}-rich fluid inclusions.

  8. Comparative oxygen barometry in granulites, Bamble sector, SE Norway

    SciTech Connect

    Harlov, D.E. )

    1992-07-01

    Oxygen fugacities have been estimated for the high-grade portion of the Bamble granulite facies terrane, SE Norway, using both titaniferous magnetite-ilmenite and orthopyroxene-titaniferous magnetite-quartz oxygen barometers. The two oxygen barometers show good agreement, for samples indicating high titaniferous magnetite-ilmenite temperatures whereas agreement is poor for low-temperature samples. Oxygen fugacities estimated from titaniferous magnetite-ilmenite are considerably lower than those estimated from orthopyroxene-titaniferous magnetite-quartz. This discrepancy increases with a decrease in temperature, which appears to reflect preferential resetting of the hematite content in the ilmenite grains, without much alteration of the more numerous titaniferous magnetite or orthopyroxene grains. The mean temperature for non-reset samples, 795 {plus minus} 60C (1{sigma}), agrees well with temperatures obtained from garnet-orthopyroxene K{sub D} exchange thermometry in the same region, 785 {plus minus} 60C (1{sigma}). The non-reset oxygen fugacities also agree well with an independent study of the Bamble granulites by Cameron. The QUIlP equilibrium (Quartz-Ulvospinel-Ilmenite-Pyroxene) is used to project self-consistent equilibrium temperatures and oxygen fugacities for samples reset due to hematite loss from the ilmenite grains. These projected temperatures and oxygen fugacities agree reasonably well with non-reset samples. The mean projected temperature is 830 {plus minus} 40C (1{sigma}). This agreement strongly supports the conclusion that low titaniferous magnetite-ilmenite temperatures (down to 485C) and accompanying low-oxygen fugacities are the result of hematite loss from the ilmenite grains at some time after granulite-facies metamorphism.

  9. Comparison of Archean and Phanerozoic granulites: Southern India and North American Appalachians

    NASA Technical Reports Server (NTRS)

    Mcsween, Harry Y., Jr.; Kittleson, Roger C.

    1988-01-01

    Archean granulites at the southern end of the Dharwar craton of India and Phanerozoic granulites in the southern Appalachians of North America share an important characteristic: both show continuous transitions from amphibolite facies rocks to higher grade. This property is highly unusual for granulite terranes, which commonly are bounded by major shears or thrusts. These two terranes thus offer an ideal opportunity to compare petrogenetic models for deep crustal rocks formed in different time periods, which conventional wisdom suggests may have had different thermal profiles. The salient features of the Archean amphibolite-to-granulite transition in southern India have been recently summarized. The observed metamorphic progression reflects increasing temperature and pressure. Conditions for the Phanerozoic amphibolite-to-granulite transition in the southern Appalachians were documented. The following sequence of prograde reactions was observed: kyanite = sillimanite, muscovite = sillimanite + K-feldspar, partial melting of pelites, and hornblende = orthopyroxene + clinopyroxene + garnet. The mineral compositions of low-variance assemblages in mafic and intermediate rocks are almost identical for the two granulite facies assemblages. In light of their different fluid regimes and possible mechanisms for heat flow augmentation, it seems surprising that these Archean and Phanerozoic granulite terranes were apparently metamorphosed under such similar conditions of pressure and temperature. Comparison with other terrains containing continuous amphibolite-to-granulite facies transitions will be necessary before this problem can be addressed.

  10. August, 2002 - floods events, affected areas revitalisation and prevention for the future in the central Bohemian region, Czech Republic

    NASA Astrophysics Data System (ADS)

    Bina, L.; Vacha, F.; Vodova, J.

    2003-04-01

    Central Bohemian Region is located in a shape of a ring surrounding the capitol of Prague. Its total territorial area is 11.014 sq.km and population of 1 130.000 inhabitants. According to EU nomenclature of regional statistical units, the Central Bohemian Region is classified as an independent NUTS II. Bohemia's biggest rivers, Vltava and Labe form the region's backbone dividing it along a north-south line, besides that there are Sazava and Berounka, the two big headwaters of Vltava, which flow through the region and there also are some cascade man made lakes and 2 important big dams - Orlik and Slapy on the Vltava River in the area of the region. Overflowing of these rivers and their feeders including cracking of high-water dams during the floods in August 2002 caused total or partial destruction or damage of more than 200 towns and villages and total losses to the extend of 450 mil. EUR. The worst impact was on damaged or destroyed human dwellings, social infrastructure (schools, kindergartens, humanitarian facilities) and technical infrastructure (roads, waterworks, power distribution). Also businesses were considerably damaged including transport terminals in the area of river ports. Flowage of Spolana Neratovice chemical works caused critical environmental havoc. Regional crisis staff with regional Governor in the lead worked continuously during the floods and a regional integrated rescue system was subordinated to it. Due to the huge extent of the floods the crisis staff coordinated its work with central bodies of state including the Government and single "power" resorts (army, interior, transport). Immediately after floods a regional - controlled management was set up including an executive body for regional revitalisation which is connected to state coordinating resort - Ministry for Local Development, EU sources and humanitarian aid. In addition to a program of regional revitalisation additional preventive flood control programs are being developed

  11. Alkaline intrusion in a granulite ensemble in the eastern ghats belt, India: Shear zone pathway and a pull-apart structure

    NASA Astrophysics Data System (ADS)

    Bhattacharya, S.; Kar, Rajib

    2004-03-01

    The alkaline complex of Koraput, Orissa, India, is one of several bodies in the high-grade Eastern Ghats belt, but this one is an integral part of the high-grade belt and remote from the western boundary against the Bastar craton. The Koraput complex forms a lozenge-shaped intrusion into the metapelitic granulites and is bounded by shear zones. The combined effect of movement along these shear zones, is a northeasterly elongated sygmoidal cavity with maximum width along the northwesterly trending Reidel shear. Thus the Koraput alkaline complex can be considered to have been emplaced in a pull-apart structure, developed in the granulitic country rocks. Moreover, in view of the fact that the western margin of the high-grade Eastern Ghats belt bears clear evidence of collisional features, rather than that of rifting or break-up, the rift-valley model for the alkaline magmatism in this high-grade belt appears untenable.

  12. Horizontal strain field of the Bohemian Massif determined from GPS measurements

    NASA Astrophysics Data System (ADS)

    Schenkova, Z.; Talich, M.; Schenk, V.

    2011-12-01

    Permanent GNSS and campaign GPS data monitored on several geodynamic networks located in the territory of the Bohemian Massif, Central Europe, allowed site movements to be determined. To constrain the first image of regional strain field for this territory a 2-D numerical modeling based on the theory of continuum mechanics under an assumption of homogeneity of the area was applied and site movements, i.e. displacement vectors, were taken as calculation inputs. This approach represents a purely geometric solution. Further attention was paid to influences of regional geological discontinuities of the Massif, by means of an evaluation of their mechanical decoupling along major faults and/or fault zones that play an important role in the distribution of the regional and local motions and stress patterns. The particular analysis of the behavior of tectonic zones in the Bohemian Massif was performed. Fundamental source of the mobility of these zones depends directly on sizes and directions of existing northward movements of structural blocks of the Alpine orogenic system. It was found that common horizontal strain field of the Bohemian Massif displays significant E-W extensions in the eastern and western parts of the Massif and mild N-S compressions in its central part. Additional analyses of the strain field pattern and its numerical uncertainties will be discussed from the viewpoint of data processing and knowledge of geological structures.

  13. Significance of Geological Units of the Bohemian Massif, Czech Republic, as Seen by Ambient Noise Interferometry

    NASA Astrophysics Data System (ADS)

    Růžek, Bohuslav; Valentová, Lubica; Gallovič, František

    2016-05-01

    Broadband recordings of 88 seismic stations distributed in the Bohemian Massif, Czech Republic, and covering the time period of up to 12 years were processed by a cross-correlation technique. All correlograms were analyzed by a novel approach to get both group and phase dispersion of Rayleigh and Love waves. Individual dispersion curves were averaged in five distinct geological units which constitute the Bohemian Massif (Saxothuringian, Teplá-Barrandean, Sudetes, Moravo-Silesian, and Moldanubian). Estimated error of the averaged dispersion curves are by an order smaller than the inherent variability due to the 3D distribution of seismic velocities within the units. The averaged dispersion data were inverted for 1D layered velocity models including their uncertainty, which are characteristic for each of the geological unit. We found that, overall, the differences between the inverted velocity models are of similar order as the variability inside the geological units, suggesting that the geological specification of the units is not fully reflected into the S-wave propagation velocities on a regional scale. Nevertheless, careful treatment of the dispersion data allowed us to identify some robust characteristics of the area. The vp to vs ratio is anomalously low (~1.6) for all the units. The Moldanubian is the most rigid and most homogeneous part of the Bohemian Massif. Middle crust in the depth range of ~3-15 km is relatively homogeneous across the investigated region, while both uppermost horizon (0-3 km) and lower crust (>15 km) exhibit lower degree of homogeneity.

  14. Southeastern slope of the Bohemian Massif: Paleogene submarine fill of the Nesvacilka depression and its importance for petroleum exploration

    SciTech Connect

    Benada, S.; Berka, J.; Brzobohaty, J.; Rehanek, J. )

    1993-09-01

    The Nesvacilka depression is a trough-like paleovalley, about 2000 m deep, that was cut at the transition from the Cretaceous to the Paleocene by fluvial erosion into Jurassic and Carboniferous strata. This morphological feature, which is superimposed on an ancient tectonic zone, trends to the present southeast boundary of the Bohemian massif and is, from a hydrocarbon exploration point of view, the most important structure in the Czech Republic. During the Paleogene, marine transgressions gradually flooded this paleovalley. In the resulting relatively closed water body, more than 1500 m of thick deeper water clastics accumulated. These clastics display features similar to those described from submarine fan lobes in other hydrocarbon-producing basins. Following the discovery of two oil and gas accumulations contained in Jurassic and Paleogene clastic rocks, exploration was focused on the central parts of the Nesvacilka depression. The depositional pattern of its Paleogene fill was worked out on the basis of well data and the results of two-dimensional and three-dimensional seismic surveys. From this, it was concluded that accumulation of the Paleogene clastic series was significantly influenced by sea level changes. The depositional concepts developed may be applied to the deeper parts of the Nesvacilka Canyon, where exploration for hydrocarbons is still at an early stage. Results obtained so far indicate that the Nesvacilka depression can be ranked as the most prospective oil play in the Czech Republic. Play concepts developed may be extrapolated to similar morphological features occurring elsewhere in the Carpathian foreland.

  15. Heterogeneity within a deep crustal strike-slip shear zone with implications for lower crustal flow, Athabasca granulite terrane, western Canadian Shield

    NASA Astrophysics Data System (ADS)

    Leslie, S. R.; Mahan, K. H.; Regan, S.; Williams, M. L.

    2011-12-01

    increasing proximity to and within the CLsz. This relationship may be explained by a mechanical emplacement of mafic and felsic granulite bodies during CLsz Neoarchean shearing, suggesting an external origin for the granulite bodies. Alternatively, this intimate m-scale relationship between mixed lithologies and the CLsz suggests that the CLsz may have localized along this zone of preexisting lithologic heterogeneity during initial Neoarchean shear. To further test these and other potential alternatives for the nature of the western Chipman domain, structural, petrological, and geochronological analyses on mafic and felsic granulites will allow for quantitative comparison between along-strike occurrences of these rocks as well as similar lithologies in other domains. The Clsz thus represents a rare opportunity to constrain the crucial role of deep crustal strike-slip shear zones in heterogeneous lower crustal flow.

  16. The main features of the interaction of mantle magmas with granulite complexes of the lower crust and their relationship with granitic melts (exemplified by the Early Caledonides of the West Baikal Region, Russia)

    NASA Astrophysics Data System (ADS)

    Vladimirov, Alexandr; Khromykh, Sergei; Mekhonoshin, Alexei; Volkova, Nina; Travin, Alexei; Mikheev, Evgeny; Vladimirova, Anna

    2016-04-01

    Granulite complexes occurring in the Early Caledonian southern folded framing of the Siberian Craton are deeply eroded fragments of the Vendian-Early Paleozoic accretionary prism, which is an indicator of the early stages of the Paleo-Asian Ocean (Gladkochub et al., 2010). The main feature of the granulite complexes is a wide development of gabbro-pyroxenites composing tectonic plates, synmetamorphic intrusive bodies, and numerous disintegrated fragments (boudins and enclaves), immersed in a metamorphic matrix. The volume of basites reaches 5-10 %, which allows us to consider mantle magmatism as a heat source for the granulite metamorphism. The most studied polygon is Chernorud granulite zone, which is a part of the Olkhon metamorphic terrane, West Baikal Region. Just this polygon was used for considering the problems of interaction of mantle magmas with lower crust granulite complexes and their relationship with granitic melts. The Chernorud Zone is a typical example of the accretionary prism with a predominance of metabasalts (70-80 %), subordinate amounts of marbles, quartzites and metapelites that have been subjected to granulite facies metamorphism and viscoelastic flow of rock masses. Study of two-pyroxene granulites (metabasalts) and garnet-sillimanite gneisses (metapelites) allows us to estimate P-T metamorphic conditions (P = 7.7-8.6 kbar, T = 770-820°C) and their U-Pb metamorphic age (530-500 Ma). Metabasalts correspond in their geochemistry to the island-arc tholeiitic series (Volkova et al., 2010; Gladkochub et al., 2010). Sin-metamorphic gabbro-pyroxenites formed in two stages: 1) Chernorud complex - tectonic slices and body's exhumed from deep earth crust levels (10-12 kb) and composed of arc tholeiitic series rocks (age T ≥ 500 Ma); 2) Ulan-Khargana complex - supply magmatic canals and fragmented tabular intrusions. This rocks composition corresponds to subalkaline petrochemical series (OIB) and U/Pb age is equal to 485±10 Ma (Travin et al., 2009

  17. Two-billion-year granulites in the late precambrian metamorphic basement along the southern peruvian coast.

    PubMed

    Dalmayrac, B; Lancelot, J R; Leyreloup, A

    1977-10-01

    Uranium-lead data indicate that the high-pressure granulitic and charnockitic nuclei within the medium-grade metamorphic complex of the Peruvian coastal area must be related to an orogenic event 2 x 10(9) years ago. As in western Africa and Brazil, this old granulitic basement is reworked by Late Precambrian orogeny. Its presence along the Peru-Chile Trench must be taken into account in interpreting the anomalously high strontium isotopic ratios of recent calc-alkaline volcanism.

  18. Significance of the late Archaean granulite facies terrain boundaries, Southern West Greenland

    NASA Technical Reports Server (NTRS)

    Friend, C. R. L.; Nutman, A. P.; Mcgregor, V. R.

    1988-01-01

    Three distinct episodes and occurrences of granulite metamorphism in West Greenland are described: (1) the oldest fragmentary granulites occur within the 3.6-Ga Amitsoq gneisses and appear to have formed 200 Ma after the continental crust in which they lie (Spatially associated rapakivi granites have zircon cores as old as 3.8 Ga, but Rb-Sr, whole-rock Pb-Pb, and all other systems give 3.6 Ga, so these granulites apparently represent a later metamorphic event); (2) 3.0-Ga granulites of the Nordlandet Peninsula NW of Godthaab, developed immediately after crustal formation in hot, dry conditions, are carbonate-free, associated with voluminous tonalite, and formed at peak metamorphic conditions of 800 C and 7 to 8 kbar (Synmetamorphic trondhjemite abounds and the activity of H2O has been indicated by Pilar to have varied greatly); and (3) 2.8-Ga granulites south of Godthaab, lie to the south of retrogressed amphibolite terranes. Prograde amphibolite-granulite transitions are clearly preserved only locally at the southern end of this block, near Bjornesund, south of Fiskenaesset. Progressively deeper parts of the crust are exposed from south to north as a major thrust fault is approached. Characteristic big hornblende pegmatites, which outcrop close to the thrust in the east, have been formed by replacement of orthopyroxene. Comparable features were not seen in South Indian granulites. It was concluded that no one mechanism accounts for the origin of all granulites in West Greenland. Various processes have interacted in different ways, and what happened in individual areas must be worked out by considering all possible processes.

  19. Deformation of Granulite at 1-2 GPa: Implications for Deep Crustal Earthquakes

    NASA Astrophysics Data System (ADS)

    Green, H. W.; Zhang, J.

    2006-12-01

    The eclogitic pseudotachylytes from western Norway demonstrate unambiguously that faulting took place in deep-seated lower crustal rock °C dry granulite, perhaps at pressures approaching 3 GPa. However, the corresponding faulting mechanism remains unclear. It is questionable whether earthquakes can occur by unassisted brittle shear fracture or frictional sliding at such depths, a fluid source is prerequisite for dehydration embrittlement and the transformation-induced faulting mechanism can only operate during polymorphic phase changes with a significant ΔV. Runaway shear heating is also problematic due to lack of evidence of large strains or rapid strain rates in the granulite. Therefore, all these potential high- pressure faulting mechanisms are unlikely to operate alone in the dry Norwegian granulites. We have conducted preliminary deformation experiments on synthetic granulite (+/- added serpentinite for fault trigger) prepared from Norway granulite kindly provided by T. M. Boundy. Rheological experiments on granulite alone show plastic flow with very high strength within and outside its stability field; no evidence was found for a faulting instability. The eclogitization process is extremely sluggish within the dry experimental samples. Most permanent strain is partitioned into feldspar; pyroxene and garnet remain almost rigid. In contrast, experiments with a short specimen of serpentinite on top of a short specimen of granulite showed that faults generated in serpentinite by dehydration propagated into granulite. The fault zones consist of fine- grained (< 1 μm) angular fragments likely to be eclogitic phase transformation products together with water. Based upon such observations, we hypothesize that pseudotachylyte formation occurs during deceleration of fault propagation rather than during acceleration as is generally assumed. Such hypothesis also has potentially important implications for fault propagation into otherwise stable materials at great

  20. Metamorphic evolution of pelitic-semipelitic granulites in the Kon Tum massif (south-central Vietnam)

    NASA Astrophysics Data System (ADS)

    Tích, Vu Van; Leyreloup, Andrey; Maluski, Henry; Lepvrier, Claude; Lo, Chinh-hua; Vượng, Nguyễn V.

    2013-09-01

    Pelitic and semipelitic anatectic granulites form one of the major lithological units in Kan Nack complex of the Kon Tum massif (in south-central Vietnam), which comprises HT metamorphic and magmatic rocks including granulites and charnockites is classically regarded as the older part of the Gondwana-derived Indosinia terrain. Metamorphic evolution study of pelitic granulite, the most abundant among granulites exposed in this massif, facilitates to understand that tectonic setting take place during the Indosinian time. The paragenetic assemblages, mineral chemistry, thermobarometry and P-T evolution path of pelitic-semipelitic granulites from Kon Tum massif has been studied in detail. Petrographic feature demonstrates that the pelitic granulite experienced prograde history, from pregranulitic conditions in the amphibolite facies up to the peak granulitic assemblages. Successive prograde reactions led to the temperature-climax giving rise to assemblages with cordierite-hercynite and cordierite-hercynite-K-feldspar. Then, as attested by the mineralogic association occurring in cordieritic coronas, these rocks have been affected by retrograde conditions coeval with a decrease of the pressure. Thermobarometic results show that the highest temperature obtained by ksp/pl thermometry is 850 °C and the highest pressure obtained by GASP (Garnet Alumino-Silicate Plagioclase) is 7.8 kbar. The obtained clockwise P-T evolution path involving heating decompression, then nearly isothermal decompression and nearly isobar cooling conditions shows that high temperature-low pressure metamorphism of the studied pelitic anatectic granulites of Kan Nack complex occurred possibly in extensional setting during the Indosinian orogeny of 260-240 Ma in age.

  1. Age and geochemical constraints for partial melting of granulites in Estonia

    NASA Astrophysics Data System (ADS)

    Soesoo, A.; Košler, J.; Kuldkepp, R.

    2006-03-01

    The rocks of the crystalline basement of the East European Craton in southern Estonia show effects of partial melting under granulite facies conditions. Zircons extracted from partial melting products (tonalite from the Tapa Zone 1824 ± 26, tonalite from the South Estonian Zone 1788 ± 16 Ma and charnockite from the Tapa Zone 1761 ± 11 Ma) yield U Pb crystallisation ages that span over approximately 80 Ma, suggesting a prolonged high-grade metamorphism or several separate events. U Pb zircon age of one sample of charnockite is concordant with the Nd model age of partial melting of its host mafic granulite facies gneiss (intercept at 1.76 Ga). Linear geochemical trends and similar initial Nd isotopic compositions of mafic granulites and charnockites suggest their possible genetic relationship. From our new and previously published data it follows that the peak granulite metamorphic conditions and formation of tonalites and charnockites (850 °C and 6 kbar) in the Estonian basement occurred at 1788 1778 Ma. Then, the rocks cooled down, passing through the garnet closure temperature of approximately 650 700 °C at 1728 ± 24 Ma. The age of metamorphism of the Estonian granulites is lower than the metamorphic ages known from southern Finland, but it is similar to the age of metamorphism reported from the Belarus-Baltic Granulite Belt in Latvia.

  2. Archean granulite gneisses from eastern Hebei Province, China: rare earth geochemistry and tectonic implications

    NASA Astrophysics Data System (ADS)

    Jahn, Bor-Ming; Zhang, Zong-Qing

    1984-03-01

    The granulite gneisses and their retrograded products of the Qianxi Group from eastern Hebei Province, China, have been investigated for their isotope and trace element geochemistry. A consistent age of about 2.5 AE has been obtained by the Rb-Sr and Sm-Nd whole-rock isochron methods, in agreement with the zircon U-Pb data (Pidgeon 1980; D.Y. Liu, unpubl.). Geochemical arguments from initial isotopic ratios (ISr and INd) and elemental distribution patterns have led us to conclude that this age of about 2.5 AE represents the time of granulite facies metamorphism, which must have followed closely the primary emplacement of their protoliths. Previous claims for early Archean ages (>3.5 AE) of these granulites are not substantiated. The mineral isotope systematics register an important thermal event at about 1.7 AE, roughly corresponding to the time of the widespread Luliang Orogeny (Ma and Wu 1981) or Chungtiao Movement (Huang 1978). The granulites of the Qianxi Group have diverse compositions ranging from ultrabasic through basic-intermediate to acid. Discriminant function calculations suggest that most analyzed samples have igneous parentage. Only a few show characteristics of metasedimentary rocks. The igneous protoliths apparently belong to two series — tholeiitic and calc-alkaline, with the latter dominating in abundance. The majority of the acid granulites have compositions corresponding to tonalite-granodiorite. Except for ultrabasic and metasedimentary rocks, all REE patterns are significantly fractionated with LREE enrichment. The degree of fractionation, as measured by the (La/Yb)N ratios, is most important in the acid granulites. These rocks often show positive Eu anomalies and HREE depletions that are typical of Archean TTG rocks (tonalitetrondhjemite-granodiorite). The existence of komatiites has been previously reported in this region. Although a few rocks have a major element chemistry similar to that for peridotitic komatiites, the lack of associated

  3. UHP-UHT peak conditions and near-adiabatic exhumation path of diamond-bearing garnet-clinopyroxene rocks from the Eger Crystalline Complex, North Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Haifler, Jakub; Kotková, Jana

    2016-04-01

    Intermediate garnet-clinopyroxene rocks from the Eger Crystalline Complex, North Bohemian Massif, contain microdiamonds enclosed in garnet and zircon. The variable mineral assemblage of these rocks allows for an evaluation of the P-T evolution using numerous univariant equilibria and thermodynamic modelling, in addition to the ternary feldspar solvus, Ti-in-garnet, Zr-in-rutile and Ti-in-zircon thermometry. Zircon mantle domains with diamond inclusions contain 111-189 ppm Ti, reflecting temperatures of 1037-1117 °C. The peak pressure consistent with diamond stability corresponds to c. 4.5-5.0 GPa. Ti-in-garnet thermometry using the Ti content of diamond-bearing garnet core yielded temperatures of 993-1039 °C at c. 5.0 GPa. An omphacite inclusion in garnet (reflecting c. 2.3-2.4 GPa at c. 1050 °C) and metastably preserved kyanite represent relics of eclogite-facies conditions. The dominant high-pressure granulite-facies mineral assemblage of low-Ca garnet, diopsidic clinopyroxene, antiperthitic feldspar and quartz equilibrated at 1.8-2.1 GPa and c. 1050 °C, based on the XGrs isopleth of the garnet mantle, garnet-feldspar-kyanite-quartz univariant equilibria and ternary feldspar solvus. Our thermodynamic modelling shows that a steep decrease of XGrs from a maximum core value of 0.32 to 0.17 at the rim as well as a rimward XMg increase (from 0.42 to 0.50) are consistent with significant decompression without heating. The latter is related to omphacite and kyanite breakdown reactions producing garnet and plagioclase. The Ti content in the rim zone of zircon (13-42 ppm), exsolved plagioclase and K-feldspar associated with matrix diopside and garnet rim, and late biotite reflect temperatures of c. 830-900 °C at c. 1.4 GPa. A similar temperature is recorded by matrix rutile grains, containing 2028-4390 ppm Zr and representing a relatively homogeneous population in contrast to rutile enclosed in garnet with variable Zr content. Our results show that the garnet

  4. Reactivity of North Bohemian coals in coprocessing of coal/oil mixtures

    SciTech Connect

    Sebor, G.; Cerny, J.; Maxa, D.; Blazek, J.; Sykorova, I.

    1995-12-01

    Autoclave experiments with North Bohemian coal were done in order to evaluate their reactivity in coprocessing with petroleum vacuum residue, Selected coals were comprehensively characterized by using a number of analytical methods. While the coals were of similar geological origin, some of their characteristics differed largely from one coal to another. Despite the differences in physical and chemical structure, the coals provided very similar yields of desired reaction products. The yields of a heavy non- distillable fraction and/or an insoluble solid residue were, under experimental conditions, largely affected by retrogressive reactions (coking). The insoluble solid fractions were examined microscopically under polarized light.

  5. Character, Distribution and Significance of Coarse Sedimentary Material in Mid-Mountain Valleys: Case Studies from Bohemian Forest Mts.

    NASA Astrophysics Data System (ADS)

    Hartvich, F.; Langhammer, J.; Taborik, P.

    2014-12-01

    The aim of this study is to collect information on the distribution, character and parameters of the coarse fluvial sediments in order to reconstruct the formation and significant changes in development of mid-mountain streams and their valleys. The studied area is situated to two small catchments in the Bohemian Forest Mts. Roklanský/Javoří brooks are observed in a 10 km long segment on the flat area of the Šumava Plateau, the Losenice R. was followed on a 7 km segment in a deeply incised, steep-sloped valley. First, the hydromorphological mapping of the floodplain and channel landforms took place to collect information on position of the fluvial landforms. The mapping was performed using the HEM methodics, developed by the authors. The Electric Resistivity Tomography was used in 20 profiles across the valleys. These cross-sections formed a backbone of the research aiming to observe the depth and distribution of the coarse sediment valley fill (above bedrock) both across the valleys and along. Next we employed digital optical granulometry using Sedimetrics software on the mapped gravel bodies, classic sieve granulometry on sandy accumulations, and on-site, in-channel boulder granulometry. Finally, magnetic susceptibility measurements were performed on suitable sediment profiles along the courses to assess the provenience of the material. There are several notions, indicated by the results of the abovementioned analyses. First, the valley floor sedimentary infill is surprisingly shallow (10-15 m), notably in the case of Javoří and Roklanský brook where the valley floor often exceeds 200 - 300 m. Also, the MS points to rather fast changes in the main sediment sources. Observations of the sediment character in the Losenice valley indicate significant role of the slope/channel coupling, namely persisting influence of large, slope-based sources of angular material (rockslides, debris flows), as well as strong impact of flood events on the valley floor morphology.

  6. Formation of Garnet Granulite in the Lower Crust of a paleo-Island Arc

    NASA Astrophysics Data System (ADS)

    Garrido, Carlos J.; Padrón-Navarta, José Alberto; López Sánchez-Vizcaíno, Vicente; Bodinier, Jean-Louis; Bosch, Delphine; Marchesi, Claudio; Hidas, Károly

    2016-04-01

    The Jijal complex (Kohistan paleo-island arc complex, NW Pakistan) is a unique occurrence of high-pressure (HP), mafic, opx-free, garnet granulite formed in the lower crust of an island arc. The upper part of the Jijal Granulitic Gabbro Unit (GGU) records the arrested transformation of hornblende gabbronorite to garnet granulite, involving the coeval breakdown of amphibole and orthopyroxene, and the formation of garnet and quartz. Close to the transformation front (2-3 cm), clinopyroxene from the granulite displays a strong Ca-tschermak zoning with lower Al-contents at rims. REE zoning of clinopyroxene and pseudosection diagrams indicate that only clinopyroxene rims reflect chemical equilibrium with garnet in the reaction front (P = 1.1 ± 0.1 GPa, T = 800 ± 50 °C), whereas the cores retained high-Al contents inherited from precursor gabbronorite clinopyroxene and remained in chemical disequilibrium within a few centimeters of the garnet granulite assemblage. Clinopyroxene of garnet granulites from the Jijal lower GGU are completely re-equilibrated with garnet (P = 1.5 ± 0.1 GPa, T = 800 ± 50 °C). If ferric iron corrections are disregarded, equilibration pressure and temperature are highly overestimated yielding exceedingly high pressures for an island arc setting. The pressure difference between the upper and lower Jijal GGU granulites (~0.4 GPa) and its current thickness (<5 km) implies delamination of the denser parts of Jijal crust. Thermodynamically computed phase diagram sections for upper GGU bulk compositions show that, at the equilibration conditions of Jijal garnet granulite, the equilibrium assemblage is orthopyroxene-free and amphibole-free garnet granulite coexisting with melt or a fluid phase, depending on the water activity at the onset of amphibole breakdown. Pseudosections indicate that hornblende gabbronorite assemblages are highly metastable at lower arc crust depths. The transformation to garnet granulite was therefore substantially

  7. P-wave velocity in granulites from South India: implications for the continental crust

    NASA Astrophysics Data System (ADS)

    Ramachandran, C.

    1992-01-01

    P-wave velocities ( Vp) were measured in 160 high-grade metamorphic rocks from the South Indian granulite terrain (SGT). The wide variations observed in the Vp of charnockites and gneisses could be due to the complex prograde and retrograde metamorphic histories of the two major rock types of the SGT. The velocity-density relation showed distinct trends for charnockites and gneisses. Initial stages of retrograde metamorphism in charnockites significantly affected their magnetic properties, however, its effect on velocity and density is not diagnostic. Contrasting physical properties on either side of the Palghat-Cauvery (P-C) shear zone lends support for the contention that the P-C shear zone is a major paleosuture. The laboratory mean Vpof the rocks from the northern SGT are comparable with the mid-crustal DSS velocity in the adjacent granite greenstone terrain (GGT), suggesting that the GGT is possibly underlain by a felsic granulite basement. The physical properties of the high-grade metamorphic rocks from SGT are significantly lower than that of the lower crust. The physical properties and tectonic considerations show that the granulites of South India may not be of lower crustal origin and hence not representative of the lower crust, as generally thought. A simplified two-layer crustal model with a predominantly felsic granulite upper crust and a mafic granulite lower crust, is suggested for the SGT.

  8. Forearc deformation and strain partitioning during growth of a continental magmatic arc: The northwestern margin of the Central Bohemian Plutonic Complex, Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Žák, Jiří; Dragoun, František; Verner, Kryštof; Chlupáčová, Marta; Holub, František V.; Kachlík, Václav

    2009-04-01

    The Late Devonian subduction followed by the Early Carboniferous continental collision of the Saxothuringian and overriding upper-crustal Teplá-Barrandian units led to the growth of a large magmatic arc (the ˜ 354-337 Ma Central Bohemian Plutonic Complex) in the central part of the Bohemian Massif. Far-field tectonic forces resulting from the collision produced ˜WNW-ESE to ˜NW-SE regional shortening across the forearc upper crust above the subduction zone; the shortening was accommodated by predominantly top-to-the-ESE tectonic transport along the southeastern flank of the Teplá-Barrandian unit. Approaching the magmatic arc margin, the regional structural pattern changes and exhibits significant across- and along-strike variations interpreted as a result of strain partitioning, where the Saxothuringian/Teplá-Barrandian convergence interacted in different ways with the intruding magma pulses. Around the voluminous, northeasterly ˜ 354 Ma Sázava pluton the principal shortening was at high angle to the forearc-facing intrusive contact and the host rocks were significantly thermally softened. The regional top-to-the-ESE tectonic transport converted here into arc-parallel ductile flow within the structural aureole around and above the pluton. In contrast, a narrow to nonexistent ductile strain aureole is preserved in the host rocks around discordant sheet-like plutons (the southwesterly pre-354 (?) Ma Marginal granite and the Milín granodiorite of unknown radiometric age). Our AMS study of the Marginal granite and Milín granodiorite, and mapping of mesoscopic magmatic foliations and lineations in another neighboring sheet-like pluton (the ˜ 346 Ma Kozárovice granodiorite), reveals sigmoidal map-scale fabric patterns consistent with dextral transpression. We thus suggest that the thin sheet-like plutons were oriented obliquely to the principal shortening and were rheologically weaker than the host rocks prior to final crystallization, producing dextral

  9. Paleomagnetic results from Cenozoic volcanics of Lusatia, NW Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Schnabl, P.; Cajz, V.; Tietz, O.; Buechner, J.; Suhr, P.; Pecskay, Z.; Cizkova, K.

    2013-05-01

    Lusatia is situated in the NE continuation of the Ohre Rift (OR) behind Lusatian Overtrust. Compared to the neighbouring volcanic complex of the České stredohorí Mts. (CS) inside the OR. The scattered occurrences of basaltic bodies in Lusatia are spread on wider area. This can be caused by different tectonic development of the regions and from derived erosional conditions. The Lusatian Overtrust, high-order tectonic structure running across the course of the OR, separates Lusatian region into two different geological areas where Cretaceous sediments or granodiorites of Lusatian Massif represent the country rock of the Cenozoic volcanism, respectively. The age of volcanic activity ranges from 19 to 33 Ma, it's proved by newly obtained Ar-Ar data from Freiberg and K-Ar data from Debrecen. Forty two scattered remnants of Cenozoic volcanic products were sampled to get paleomagnetic data. The superficial volcanics with detectable geological position and volcanology were chosen preferentially, several dykes and separate vents were sampled as well. Paleomagnetic research was processed on more than 500 samples which were demagnetized using alternate field in the range 0-80 mT. Q-ratio was counted to prevent the lightning influence - solitary volcanic occurrences build positive morphology and thus, they are prone to be targeted by lightnings. The values of Q-ratio predominantly span from 0.1 to 7.0; those samples having the value over 10, were excluded for evaluation. The mean paleomagnetic direction (MPD) was acquired from several samples on each sampling site. Declination and Inclination show values of 11.8 deg and 62.7 deg (α95 = 9.3 deg) for normal polarity, or 182.1 deg and -59.2 deg (α95 = 6.1 deg) for reverse polarity, respectively,The corresponding paleolatitude of 41.9 deg was counted from the Inclination. This is 1000 km to the South, compared to recent position. The dispersions of the MPD are relatively wide. This coincides well with the idea of long

  10. Thermal contraints on high-pressure granulite metamorphism of supracrustal rocks

    NASA Technical Reports Server (NTRS)

    Ashwal, L. D.; Morgan, P.; Leslie, W. W.

    1983-01-01

    The circumstances leading to the formation and exposure at the Earth's surface of supracrustal granulites are examined. These are defined as sediments, volcanics, and other rock units which originally formed at the surface of the Earth, were metamorphosed to high-pressure granulite facies (T = 700-900 C, P = 5-10 kbar), and reexposed at the Earth's surface, in many cases underlain by normal thicknesses of continental crust (30-40 km). Five possible heating mechanisms to account for granulite metamorphism of supracrustal rocks are discussed: magnetic heating, thermal relaxation of perturbed temperature profiles following underthrusting of the continental crust, thermal relaxation after underthrusting of thin slivers of supracrustal rocks below continental crust of normal thickness, major preheating of the upper plate, and shear heating caused by frictional stress along the thrust plane.

  11. Polymetamorphic evolution of the granulite-facies Paleoproterozoic basement of the Kabul Block, Afghanistan

    NASA Astrophysics Data System (ADS)

    Collett, Stephen; Faryad, Shah Wali; Mosazai, Amir Mohammad

    2015-08-01

    The Kabul Block is an elongate crustal fragment which cuts across the Afghan Central Blocks, adjoining the Indian and Eurasian continents. Bounded by major strike slip faults and ophiolitic material thrust onto either side, the block contains a strongly metamorphosed basement consisting of some of the only quantifiably Proterozoic rocks south of the Herat-Panjshir Suture Zone. The basement rocks crop-out extensively in the vicinity of Kabul City and consist predominantly of migmatites, gneisses, schists and small amounts of higher-grade granulite-facies rocks. Granulite-facies assemblages were identified in felsic and mafic siliceous rocks as well as impure carbonates. Granulite-facies conditions are recorded by the presence of orthopyroxene overgrowing biotite in felsic rocks; by orthopyroxene overgrowing amphibole in mafic rocks and by the presence of olivine and clinohumite in the marbles. The granulite-facies assemblages are overprinted by a younger amphibolite-facies event that is characterized by the growth of garnet at the expense of the granulite-facies phases. Pressure-temperature (P-T) conditions for the granulite-facies event of around 850 °C and up to 7 kbar were calculated through conventional thermobarometry and phase equilibria modeling. The younger, amphibolite-facies event shows moderately higher pressures of up to 8.5 kbar at around 600 °C. This metamorphism likely corresponds to the dominant metamorphic event within the basement of the Kabul Block. The results of this work are combined with the litho-stratigraphic relations and recent geochronological dating to analyze envisaged Paleoproterozoic and Neoproterozoic metamorphic events in the Kabul Block.

  12. Stable isotope studies on granulites from the high grade terrain of Southern India

    NASA Technical Reports Server (NTRS)

    Jackson, D. H.; Santosh, M.; Mattey, D. P.; Harris, N. B. W.

    1988-01-01

    Fluid inclusion and petrologic characteristics of South India granulites and their bearing on the sources of metamorphic fluids are discussed. This paper served as a review and an introduction to the next paper by D. Jackson. Jackson presented carbon isotope data from gases extracted from fluid inclusions in South Indian granulites. The uniformly low Delta C-13 values (minus 10 plus or minus 2 per mil) and the greater abundance of CO2 in the incipient charnockites are suggestive of fluid influx from an externally buffered reservoir.

  13. In Situ Chemical Characterization of Mineral Phases in Lunar Granulite Meteorite Northwest Africa 5744

    NASA Technical Reports Server (NTRS)

    Kent, J. J.; Brandon, A. D.; Lapen, T. J.; Peslier, A. H.; Irving, A. J.; Coleff, D. M.

    2012-01-01

    Northwest Africa (NWA) 5744 meteorite is a granulitic and troctolitic lunar breccia which may represent nearly pristine lunar crust (Fig. 1). NWA 5744 is unusually magnesian compared to other lunar breccias, with bulk [Mg/(Mg+Fe)] 0.79 [1, 2]. Inspection shows impactor content is likely to be very minor, with low Ni content and a lack of metal grains. Some terrestrial contamination is present, evidenced by calcite within cracks. NWA 5744 has notably low concentrations of incompatible trace elements (ITEs) [2]. The goal of this study is to attempt to classify this lunar granulite through analyses of in situ phases.

  14. The granulite suite: Impact melts and metamorphic breccias of the early lunar crust

    NASA Technical Reports Server (NTRS)

    Cushing, J. A.; Taylor, G. J.; Norman, M. D.; Keil, K.

    1993-01-01

    The granulite suite consists of two major types of rocks. One is coarse-grained and poikilitic with many euhedral crystals of olivine and plagioclase. These characteristics indicate crystallization from a melt; the poikilitic granulites are impact melt breccias. The other group is finer-grained and granoblastic, with numerous triple junctions; the granoblastic granulites are metamorphic rocks. Compositional groups identified by Lindstrom and Lindstrom contain both textural types. Two pyroxene thermometry indicates that both groups equilibrated at 1000 to 1150 C. Calculations suggest that the granoblastic group, which has an average grain size of about 80 microns, was annealed for less than 6 x 10 exp 4 y at 1000 C, and for less than 2500 y at 1150 C. Similar equilibration temperatures suggest that both groups were physically associated after impact events produced the poikilitic melts. Granulitic impactites hold important information about the pre-Nectarian bombardment history of the Moon, and the composition and thermal evolution of the early lunar crust. Granulitic impactites are widely considered to be an important rock type in the lunar crust, but how they formed is poorly understood. Metal compositions and elevated concentrations of meteoritic siderophile elements suggest that most lunar granulites are impact breccias. Their occurrence as clasts in approximately 3.9 Ga breccias, and Ar-(40-39) ages greater than or = 4.2 Ga for some granulites show that they represent a component of the lunar crust which formed prior to the Nectarian cataclysm. Petrographic characteristics of lunar granulites indicate at least two endmember textural variants which apparently formed in fundamentally different ways. One type has granoblastic textures consisting of equant, polygonal to rounded grains, and abundant triple junctions with small dispersions around 120 degrees indicating a close approach to textural equilibrium. As suggested by many authors, granoblastic granulites

  15. Mass transfer and trace element redistribution during hydration of granulites in the Bergen Arcs, Norway

    NASA Astrophysics Data System (ADS)

    Centrella, Stephen; Austrheim, Håkon; Putnis, Andrew

    2016-10-01

    The Bergen Arcs, located on the western coast of Norway, are characterized by Precambrian granulite facies rocks partially hydrated at amphibolite and eclogite facies conditions. At Hilland Radöy, granulite displays sharp hydration fronts across which the granulite facies assemblage composed of garnet (55%) and clinopyroxene (45%) is replaced by an amphibolite facies mineralogy defined by chlorite, epidote, and amphibole. The replacement of both phases is pseudomorphic and the overall reaction is isovolumetric. In the present study, LA ICPMS has been used to determine the trace element redistribution during the hydration. Although the bulk concentrations of the trace elements do not change, the LILE, HFSE, and REE losses and gains in replacing the garnet are qualitatively balanced by the opposite gains and losses associated with the replacement of clinopyroxene. From the REE compositions of the parent granulite and the product amphibolite, measured in μg/cm3, we conclude that the mass of rock lost to the fluid phase during the hydration is approximately 20%. This suggests a mechanism for coupling between the local stress generated by hydration reactions and mass transfer, dependent on the spatial scale over which the system is open.

  16. Ultrahigh-Temperature Metamorphism in Madurai Granulites, Southern India: Evidence from Carbon Isotope Thermometry.

    PubMed

    Satish-Kumar

    2000-07-01

    Ultrahigh-temperature (UHT) metamorphism in the Madurai Block of the southern Indian granulite terrain has been verified using the calcite-graphite isotope exchange thermometer. Carbon isotope thermometry has been applied to marbles from a locality near the reported occurrence of sapphirine granulites that have yielded temperature estimates of around 1000 degrees C. The delta(13)C and delta(18)O values of calcite are homogenous, implying equilibration of the isotopes during metamorphism. However, the delta(13)C values of single graphite crystals show variations in the order of 1 per thousand within a hand specimen. Detailed isotopic zonation studies indicate that graphite preserves either the time-integrated crystal growth history or reequilibrium fractionation during its cooling history. The graphite cores preserve higher delta(13)C values than the rims. The fractionation between calcite and graphite cores gives the highest metamorphic temperature of about 1060 degrees C, which matches the petrologically inferred temperature estimates in the high-magnesian pelites. The fractionation between graphite rims and calcite suggests a temperature of around 750 degrees C, which is interpreted to reflect retrograde cooling. This event is also observed in the sapphirine granulites. Calcite-graphite thermometry thus provides a useful tool to define UHT metamorphism in granulite terrains.

  17. Petrology and geochemistry of lower crustal granulites from the Geronimo Volcanic Field, southeastern Arizona

    SciTech Connect

    Kempton, P.D.; Hawkesworth, C.J. ); Harmon, R.S. ); Moorbath, S. )

    1990-12-01

    Mafic to intermediate composition granulite xenoliths occur in Pliocene to Recent alkali basalts from the Geronimo Volcanic Field (GVF), southeastern Arizona, USA. The range of compositions and mineral assemblages observed suggests that the ultimate derivation of these rocks is from a variety of protoliths and that more than one mechanism has operated during the geologic evolution of the lower crust in this area. Two-pyroxene, two-feldspar granulites (meta-diorites) have major and trace element characteristics similar to estimates of post-Archaen lower crust. Low {sup 143}Nd/{sup 144}Nd values and Proterozoic Nd-depleted-mantle model ages (1.2-1.4 Ga) for these rocks require that Precambrian material exists in the lower crust of southeastern Arizona, either as the meta-diorites themselves or as older crust available for melting during production of the meta-diorite protoliths. K-feldspar-free granulites have more mafic compositions and their trace element characteristics are consistent with a cumulate origin. A negative correlation of {sup 208}Pb/{sup 204}Pb vs. {sup 206}Pb/{sup 204}Pb suggests that the meta-cumulate granulites represent mixing between Basin and Range age lavas with older meta-diorite crust and is, thus, evidence for Cenozoic underplating of the lower crust beneath the Basin and Range.

  18. Origin and geodynamic significance of the early Mesozoic Weiya LP and HT granulites from the Chinese Eastern Tianshan

    NASA Astrophysics Data System (ADS)

    Mao, Ling-Juan; He, Zhen-Yu; Zhang, Ze-Ming; Klemd, Reiner; Xiang, Hua; Tian, Zuo-Lin; Zong, Ke-Qing

    2015-12-01

    The Chinese Tianshan in the southwestern part of the Central Asian Orogenic Belt (CAOB) is characterized by a variety of high-grade metamorphic rocks, which provide critical constraints for understanding the geodynamic evolution of the CAOB. In this paper, we present detailed petrological and zircon U-Pb geochronological studies of the Weiya low-pressure and high-temperature (LP-HT) granulites of the Chinese Eastern Tianshan. These granulites were previously considered to be a product of a regional metamorphic orogenic event. Due to different bulk-rock chemistries the Weiya granulites, which occur as lenses within the contact metamorphic aureole of the Weiya granitic ring complex, have a variety of felsic-pelitic and mafic granulites with different textural equilibrium mineral assemblages including garnet-cordierite-sillimanite-bearing granulites, cordierite-sillimanite-bearing granulites, cordierite-orthopyroxene-bearing granulites, and orthopyroxene-clinopyroxene-bearing granulites. Average P-T thermobarometric calculations and conventional geothermobarometry indicates that the Weiya granulites underwent early prograde metamorphism under conditions of 600-650 °C at 3.2-4.2 kbar and peak metamorphism of 750-840 °C at 2.9-6.3 kbar, indicating a rather high geothermal gradient of ca. 60 °C/km. Zircon U-Pb LA-ICP-MS dating revealed metamorphic ages between 244 ± 1 to 237 ± 3 Ma, which are in accordance with the crystallization age of the Weiya granitic ring complex. We suggest that the formation of the Weiya granulites was related to contemporaneous granitic magmatism instead of a regional metamorphic orogenic event. In addition, a Late Devonian metamorphic age of ca. 380 Ma was recorded in zircon mantle domains from two pelitic samples which is consistent with the metamorphic age of the Xingxingxia metamorphic complex in the Chinese Eastern Tianshan. This suggests that the mantle domains of the zircon grains of the Weiya granulites probably formed during the

  19. Magmatic to solid state fabrics in syntectonic granitoids recording early Carboniferous orogenic collapse in the Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Žák, Jiří; Verner, Kryštof; Holub, František V.; Kabele, Petr; Chlupáčová, Marta; Halodová, Patricie

    2012-03-01

    The ˜354-336 Ma Central Bohemian Plutonic Complex is a Variscan magmatic arc that developed in the central Bohemian Massif in response to subduction of the Saxothuringian lithosphere beneath the Teplá-Barrandian microplate. Magmatic to solid state fabrics in the most voluminous portion of this arc (the ˜346 Ma Blatná pluton) record two superposed orogenic events: dextral transpression associated with arc-parallel stretching and arc-perpendicular shortening, and normal shearing associated with exhumation of the high-grade core of the orogen (Moldanubian unit). This kinematic switch is an important landmark in the evolution of this segment of the Variscan belt for it marks the cessation of subduction-related compressive forces in the upper crust giving way to gravity-driven normal movements of the Teplá-Barrandian hanging wall block relative to the high-grade Moldanubian footwall. We use thermal modeling to demonstrate that the emplacement of huge volumes of arc magmas and their slow cooling produced a thermally softened domain in the upper crust and that the magmatic arc granitoids may have played a major role in initiating the orogenic collapse in the Bohemian Massif through lubrication and reactivation of a pre-existing lithospheric boundary and decreasing the overall strength of the rigid orogenic lid.

  20. Experimental constraints on ultrapotassic magmatism from the Bohemian Massif (durbachite series, Czech Republic)

    NASA Astrophysics Data System (ADS)

    Parat, Fleurice; Holtz, François; René, Miloš; Almeev, Renat

    2010-03-01

    The equilibrium phase relations of a mafic durbachite (53 wt.% SiO2) from the Třebíč pluton, representative of the Variscan ultrapotassic magmatism of the Bohemian Massif (338-335 Ma), have been determined as a function of temperature (900-1,100°C), pressure (100-200 MPa), and H2O activity (1.1-6.1 wt.% H2O in the melt). Two oxygen fugacity ranges were investigated: close to the Ni-NiO (NNO) buffer and 2.6 log unit above NNO buffer (∆NNO + 2.6). At 1,100°C, olivine is the liquidus phase and co-crystallized with phlogopite and augite at 1,000°C for the whole range of investigated pressure and water content in the melt. At 900°C, the mineral assemblage consists of augite and phlogopite, whereas olivine is not stable. The stability field of both alkali feldspar and plagioclase is restricted to low pressure (100 MPa) at nearly water-saturated conditions (<3-4 wt.% H2O) and T < 900°C. A comparison between experimental products and natural minerals indicates that mafic durbachites have a near-liquidus assemblage of olivine, augite, Ti-rich phlogopite, apatite and zircon, followed by alkali feldspar and plagioclase, similar to the mineral assemblage of minette magma. Natural amphibole, diopside and orthopyroxene were not reproduced experimentally and probably result from sub-solidus reactions, whereas biotite re-equilibrated at low temperature. The crystallization sequence olivine followed by phlogopite and augite reproduces the sequence inferred in many mica-lamprophyre rocks. The similar fractionation trends observed for durbachites and minettes indicate that mafic durbachites are probably the plutonic equivalents of minettes and that K- and Mg-rich magmas in the Bohemian Massif may have been generated from partial melting of a phlogopite-clinopyroxene-bearing metasomatized peridotite. Experimental melt compositions also suggest that felsic durbachites can be generated by simple fractionation of a more mafic parent and mixing with mantle-derived components at

  1. Mantle anisotropy of the Bohemian Massif as seen by SKS-wave splitting

    NASA Astrophysics Data System (ADS)

    Vecsey, Ludek; Plomerova, Jaroslava; Babuska, Vladislav

    2014-05-01

    The Bohemian Massif (BM) assembled during the collision of Laurasia (Laurentia-Baltica) and Gondwana as a part of the Armorican Terrane Assemblage. It represents the estern-most outcrop of the European Variscan belt. The detailed tomographic and seismic anisotropy research of the deep structure of the BM has proceeded in several passive seismic experiments: BOHEMA I (2001-2003), BOHEMA II (2004-2005), BOHEMA III (2005-2006), PASSEQ (2006-2008) and Eger Rift (2007-2011). During these periods, the whole massif was stepwise covered by networks of temporal short-period and broad-band stations that recorded large amount of data from teleseismic events. The inferences from seismic anisotropy image the Bohemian Massif as a mosaic of microplates with a rigid mantle lithosphere preserving a fossil olivine fabric. The mantle domains can be associated with the tectonic units recognized by geological studies: Saxothuringian (ST), Teplá-Barrandian (TB), Moldanubian (MB) and finally Moravian (M) and Silesian (S) parts of the MS Zone, overlying the Brunovistulian mantle lithosphere. In this contribution, we concetrate on the large-scale mantle anisotropy modelled from splitting of SKS waves and their particle motion (PM). An advantage of using PM analysis is its ability to employ even events with lower signal-to-noise ratio (SNR) that are otherwise not usable for splitting analysis. To improve results of splitting analysis of signals distorted by noise, we use stacking of individual splitting measurements from waves closely propagating through the mantle. Another way of improving our analysis is a stacking of individual splittings of a single event measured at nearby stations. On average, the fast shear waves are polarized in the E-W direction in the ST, MD, TB units, but exhibit different regional variations of the splitting parameters in dependence on back-azimuths. Thus, different lithosphere mantle fabrics in the ST, MD and TB units were modelled. Moreover, the ST unit can

  2. Timing and duration of garnet granulite metamorphism in magmatic arc crust, Fiordland, New Zealand

    USGS Publications Warehouse

    Stowell, H.; Tulloch, A.; Zuluaga, C.; Koenig, A.

    2010-01-01

    Pembroke Granulite from Fiordland, New Zealand provides a window into the mid- to lower crust of magmatic arcs. Garnet Sm-Nd and zircon U-Pb ages constrain the timing and duration of high-P partial melting that produced trondhjemitic high Sr/Y magma. Trace element zoning in large, euhedral garnet is compatible with little post growth modification and supports the interpretation that garnet Sm-Nd ages of 126.1??2.0 and 122.6??2.0. Ma date crystal growth. Integration of the garnet ages with U-Pb zircon ages elucidates a history of intrusion(?) and a protracted period of high-temperature metamorphism and partial melting. The oldest zircon ages of 163 to 150. Ma reflect inheritance or intrusion and a cluster of zircon ages ca. 134. Ma date orthopyroxene-bearing mineral assemblages that may be magmatic or metamorphic in origin. Zircon and garnet ages from unmelted gneiss and garnet reaction zones record garnet granulite facies metamorphism at 128 to 126. Ma. Peritectic garnet and additional zircon ages from trondhjemite veins and garnet reaction zones indicate that garnet growth and partial melting lasted until ca. 123. Ma. Two single fraction garnet ages and young zircon ages suggest continued high-temperature re-equilibration until ca. 95. Ma. Phase diagram sections constrain orthopyroxene assemblages to <0.6 GPa @ 650??C, peak garnet granulite facies metamorphic conditions to 680-815??C @ 1.1-1.4. GPa, and a P-T path with a P increase of???0.5. GPa. These sections are compatible with water contents???0.28wt.%, local dehydration during garnet granulite metamorphism, and <0.3. GPa P increases during garnet growth. Results demonstrate the utility of integrated U-Pb zircon and Sm-Nd garnet ages, and phase diagram sections for understanding the nature, duration, and conditions of deep crustal metamorphism and melting. Geochronologic and thermobarometric data for garnet granulite indicate that thickening of arc crust, which caused high-pressure metamorphism in northern

  3. Mass transfer and trace element redistribution during hydration of granulites in the Bergen Arcs, Norway.

    NASA Astrophysics Data System (ADS)

    Centrella, Stephen; Austrheim, Håkon; Putnis, Andrew

    2016-04-01

    The Bergen Arcs located on the Western coast of Norway are characterized by Precambrian granulite facies rocks partially hydrated at amphibolite and eclogite facies conditions. Over an area of ca. 1000 km², relict of granulite facies lenses make up only ca. 10% of the observed outcrops. At Hilland Radöy, granulite displays sharp hydration fronts across which the granulite facies assemblage composed of garnet (55%) and clinopyroxene (45%) is replaced by an amphibolite facies mineralogy defined by chlorite, epidote and amphibole. The major element bulk composition does not change significantly across the hydration front, apart from the volatile components (loss on ignition, LOI) that increases from 0.17 wt.% in the granulite to 2.43 wt.% in the amphibolite (Centrella et al., 2015). The replacements of garnet and clinopyroxene are pseudomorphic indicating a perfect preservation of the parent crystal shape. The textural evolution during the replacement is consistent with the coupled dissolution-precipitation mechanism where garnet is replaced by chlorite, epidote and pargasite and clinopyroxene by hornblende and quartz. Based on the observations of an isovolumetric replacement, the mass loss during hydration was estimated at 13%. This study is based on the trace element redistribution during the hydration using the same samples as Centrella et al. (2015). The local mass transfer during the replacement process determined from the major element is also confirmed by the trace element redistribution. The LILE, HFSE and REE losses and gains in replacing the garnet are approximately balanced by the opposite gains and losses associated with the replacement of clinopyroxene. Because the hydration involves reduction of rock density, the volume preservation (isovolumetric reaction), together with the mass balance calculations, requires a significant loss of the mass of the rock to the fluid phase: 13% based on the major element redistribution and around 20% based on the REE

  4. 40Ar- 39Ar geochronology of the charnockites and granulites of the Kan Nack complex, Kon Tum Massif, Vietnam

    NASA Astrophysics Data System (ADS)

    Maluski, Henri; Lepvrier, Claude; Leyreloup, André; Tich, Vu Van; Thi, Phan Truong

    2005-07-01

    The Truong Son Belt forms the eastern rim of the Indochina Block in Southeast Asia. The age of the metamorphism, mainly along NW-SE mylonitic shear zones that affects this belt, has been formerly determined at about 240-250 Ma. This age corresponds to the Indosinian tectonometamorphic episode. The Kon Tum Massif, situated to the south of this belt, comprises high-temperature rocks, the Kan Nack Complex, including charnockites and granulites. The main charnockitic outcrops, restricted to the Song Ba Valley, establish the intrusive nature of these magmatic rocks within granulite facies material. Basic charnockitic rocks are mainly quartz enderbites to norites and hornblende-pyroxene granulite facies rocks. The 40Ar- 39Ar age of intrusion-cooling of charnockitic magmas is determined from primary magmatic biotites at about 245 Ma. In the east of the Kan Nack Complex some granulite facies rocks exhibit relicts of primary granulite facies parageneses, whereas others show evidence of overprinting by a retrogressive low-grade metamorphism. Ar-Ar dating confirm this evolution, giving ages of 400 Ma for primary relict granulite facies phases and 260-270 Ma from the most retrogressed samples establishing the youngest limit for the granulite facies metamorphism. Granulites intruded by charnockites in the Song Ba Valley yield ages of about 250 Ma, equivalent to the ages of the charnockites, and have evidently been completely reset by these high temperature intrusions. Therefore, the Kan Nack Complex of the Kon Tum Massif is not an independent unit with respect to the Indosinian orogen, but represents the deep-crustal part of this belt.

  5. Magnesian anorthositic granulites in lunar meteorites Allan Hills A81005 and Dhofar 309: Geochemistry and global significance

    NASA Astrophysics Data System (ADS)

    Treiman, Allan H.; Maloy, Amy K.; Shearer, Charles K.; Gross, Juliane

    2010-02-01

    Fragments of magnesian anorthositic granulite are found in the lunar highlands meteorites Allan Hills (ALH) A81005 and Dhofar (Dho) 309. Five analyzed clasts of meteoritic magnesian anorthositic granulite have Mg' [molar Mg/(Mg+Fe)]=81-87 FeO~5%wt Al2O3~22% wt; rare earth elements abundances~0.5-2×CI (except Eu~10×CI) and low Ni and Co in a non-chondritic ratio. The clasts have nearly identical chemical compositions, even though their host meteorites formed at different places on the Moon. These magnesian anorthositic granulites are distinct from other highlands materials in their unique combination of mineral proportions, Mg', REE abundances and patterns, Ti/Sm ratio, and Sc/Sm ratio. Their Mg' is too high for a close relationship to ferroan anorthosites, or to have formed as flotation cumulates from the lunar magma ocean. Compositions of these magnesian anorthositic granulites cannot be modeled as mixtures of, or fractionates from, known lunar rocks. However, compositions of lunar highlands meteorites can be represented as mixtures of magnesian anorthositic granulite, ferroan anorthosite, mare basalt, and KREEP. Meteoritic magnesian anorthositic granulite is a good candidate for the magnesian highlands component inferred from Apollo highland impactites: magnesian, feldspathic, and REE-poor. Bulk compositions of meteorite magnesian anorthositic granulites are comparable to those inferred for parts of the lunar farside (the Feldspathic Highlands Terrane): ~4.5 wt% FeO; ~28 wt% Al2O3; and Th<1ppm. Thus, magnesian anorthositic granulite may be a widespread and abundant component of the lunar highlands.

  6. Evolution of high-pressure mafic granulites and pelitic gneisses from NE Madagascar: Tectonic implications

    NASA Astrophysics Data System (ADS)

    Ishwar-Kumar, C.; Sajeev, K.; Windley, B. F.; Kusky, T. M.; Feng, P.; Ratheesh-Kumar, R. T.; Huang, Y.; Zhang, Y.; Jiang, X.; Razakamanana, T.; Yagi, K.; Itaya, T.

    2015-11-01

    The occurrence of high-pressure mafic-ultramafic bodies within major shear zones is one of the indicators of paleo-subduction. In mafic granulites of the Andriamena complex (north-eastern Madagascar) we document unusual textures including garnet-clinopyroxene-quartz coronas that formed after the breakdown of orthopyroxene-plagioclase-ilmenite. Textural evidence and isochemical phase diagram calculations in the Na2O-CaO-K2O-FeO-MgO-Al2O3-SiO2-H2O-TiO2 system indicate a pressure-temperature (P-T) evolution from an isothermal (780 °C) pressure up to c. 24 kbar to decompression and cooling. Such a P-T trajectory is typically attained in a subduction zone setting where a gabbroic/ultramafic complex is subducted and later exhumed to the present crustal level during oceanic closure and final continental collision. The present results suggest that the presence of such deeply subducted rocks of the Andriamena complex is related to formation of the Betsimisaraka suture. LA-ICPMS U-Pb zircon dating of pelitic gneisses from the Betsimisaraka suture yields low Th/U ratios and protolith ages ranging from 2535 to 2625 Ma. A granitic gneiss from the Alaotra complex yields a zircon crystallization age of ca. 818 Ma and Th/U ratios vary from 1.08 to 2.09. K-Ar dating of muscovite and biotite from biotite-kyanite-sillimanite gneiss and garnet-biotite gneiss yields age of 486 ± 9 Ma and 459 ± 9 Ma respectively. We have estimated regional crustal thicknesses in NE Madagascar using a flexural inversion technique, which indicates the presence of an anomalously thick crust (c. 43 km) beneath the Antananarivo block. This result is consistent with the present concept that subduction beneath the Antananarivo block resulted in a more competent and thicker crust. The textural data, thermodynamic model, and geophysical evidence together provide a new insight to the subduction history, crustal thickening and evolution of the high-pressure Andriamena complex and its link to the terminal

  7. Protolith age of Santa Maria Chico granulites dated on zircons from an associated amphibolite-facies granodiorite in southernmost Brazil.

    PubMed

    Hartmann, Léo A; Liu, Dunyi; Wang, Yenbin; Massonne, Hans-Joachim; Santos, João O S

    2008-09-01

    U-Pb dating of zircon was undertaken with the Beijing SHRIMP II (sensitive high resolution ion microprobe) on anamphibolite facies granodiorite and an almandine-albite granulite from the Santa Maria Chico Granulitic Complex, southern Brazilian Shield. This work was also done to unravel protolith ages which are often hidden in the array of partly reset data. The obtained metamorphic ages of the granodiorite gneiss and the granulite are 2035 +/- 9 Ma and 2006 +/- 3 Ma, respectively. These data are within the range of metamorphic ages determined in previous studies (2022 +/- 18 Ma and 2031 +/- 40 Ma). However, protolith ages for the granodiorite (2366 +/- 8 Ma) and the granulite (2489 +/- 6 Ma) were obtained which are outside the previously recognized range (> 2510-2555 Ma). The magmatic protolith age of the granodiorite refers to a previously little known magmatic event in the shield. Further investigations may demonstrate that amphibolite facies zircon crystals are useful as a window into geological events in associated granulites, because zircon ages are blurred in the studied granulites.

  8. On the occurrence of Ctenocheles (Decapoda, Axiidea, Ctenochelidae) in the Bohemian Cretaceous Basin

    PubMed Central

    HYŽNÝ, MATÚŠ; VESELSKÁ, MARTINA KOČOVÁ; DVOŘÁK, PAVEL

    2015-01-01

    Because of close morphological affinities, fossil cheliped fragments of the ghost shrimp Ctenocheles (Decapoda, Axiidea, Ctenochelidae) can be easily misidentified as remains of different decapod crustacean taxa. Re-examination of the Cretaceous decapods deposited in the National Museum in Prague revealed that all supposed specimens of the lobster genus Oncopareia found in the Middle Coniacian calcareous claystones of the Březno Formation, including one of the Fritsch’s original specimens of Stenocheles parvulus, actually belong to Ctenocheles. This material together with newly collected specimens from the same locality, allowed for erection of a new species, Ctenocheles fritschi. Its major chela possesses a serrated ischium and ovoid, unarmed merus; therefore, it is considered a close relative of the extant C. collini and C. maorianus. Ctenocheles fritschi sp. nov. represents the first report on the occurrence of the genus from the Bohemian Cretaceous Basin. It is one of the oldest records of Ctenocheles and simultaneously one of the best preserved fossils of the genus reported to date. Confusing taxonomy of S. parvulus is reviewed and shortly discussed. PMID:25983568

  9. Adjusting stream-sediment geochemical maps in the Austrian Bohemian Massif by analysis of variance

    USGS Publications Warehouse

    Davis, J.C.; Hausberger, G.; Schermann, O.; Bohling, G.

    1995-01-01

    The Austrian portion of the Bohemian Massif is a Precambrian terrane composed mostly of highly metamorphosed rocks intruded by a series of granitoids that are petrographically similar. Rocks are exposed poorly and the subtle variations in rock type are difficult to map in the field. A detailed geochemical survey of stream sediments in this region has been conducted and included as part of the Geochemischer Atlas der Republik O??sterreich, and the variations in stream sediment composition may help refine the geological interpretation. In an earlier study, multivariate analysis of variance (MANOVA) was applied to the stream-sediment data in order to minimize unwanted sampling variation and emphasize relationships between stream sediments and rock types in sample catchment areas. The estimated coefficients were used successfully to correct for the sampling effects throughout most of the region, but also introduced an overcorrection in some areas that seems to result from consistent but subtle differences in composition of specific rock types. By expanding the model to include an additional factor reflecting the presence of a major tectonic unit, the Rohrbach block, the overcorrection is removed. This iterative process simultaneously refines both the geochemical map by removing extraneous variation and the geological map by suggesting a more detailed classification of rock types. ?? 1995 International Association for Mathematical Geology.

  10. Crustal structure and tectonics of the northern part of the Southern Granulite Terrane, India

    USGS Publications Warehouse

    Rao, V.V.; Sain, K.; Reddy, P.R.; Mooney, W.D.

    2006-01-01

    Deep seismic reflection studies investigating the exposed Archean lower continental crust of the Southern Granulite Terrane, India, yield important constraints on the nature and evolution of the deep crust, including the formation and exhumation of granulites. Seismic reflection images along the Kuppam-Bhavani profile reveal a band of reflections that dip southward from 10.5 to 15.0??s two-way-time (TWT), across a distance of 50??km. The bottom of these reflections beneath the Dharwar craton is interpreted as the Moho. Further south, another reflection band dipping northward is observed. These bands of reflectivity constitute a divergent reflection fabric that converges at the Moho boundary observed at the Mettur shear zone. Reflection fabrics that intersect at a steep angle are interpreted as a collisional signature due to the convergence of crustal blocks, which we infer resulted in crustal thickening and the formation of granulites. Anomalous gravity and magnetic signatures are also observed across the Mettur shear zone. The gravity model derived from the Bouguer gravity data corroborates seismic results. The tectonic regime and seismic reflection profiles are combined in a 3-D representation that illustrates our evidence for paleo-subduction at a collision zone. The structural dissimilarities and geophysical anomalies suggest that the Mettur shear zone is a suture between the Dharwar craton in the north and another crustal block in the south. This study contributes significantly to our understanding of the operation of Archean plate tectonics, here inferred to involve collision and subduction. Furthermore, it provides an important link between the Gondwanaland and global granulite evolution occurring throughout the late Archean. ?? 2006 Elsevier B.V. All rights reserved.

  11. Magnetism of the lower crust: Observations from the Chipman Domain, Athabasca Granulite Terrain, northern Canada

    NASA Astrophysics Data System (ADS)

    Brown, Laurie L.; Webber, Jeffery; Williams, Michael; Regan, Sean; Seaman, Sheila

    2014-06-01

    Magnetic properties of lower crustal rocks produce anomalies seen in satellite, aeromagnetic, and ground studies, and are assumed to be responsible for observed long wave-length anomalies (LWA) of +/- 20 nT. The soon to be launched SWARM satellites will provide extensive data on the magnetization of the lower to middle crust. In anticipation of this event we are investigating magnetic properties in a superbly exposed section of lower crust in northern Saskatchewan. The Athabasca Granulite Terrain (AGT) is a complex region of felsic and mafic lower crustal rocks, part of the Snowbird Tectonic zone, stretching NE-SW across the Canadian Shield. The AGT is composed of a sequence of rocks identified as lower crustal in origin by their high pressure (> 1.0 GPa) and high temperature (~ 800 °C) metamorphism, dated at 2.6 Ga and 1.9 Ga, with uplift and exhumation at 1.85-1.80 Ga. The AGT is characterized by low (negative) aeromagnetic anomalies with distinct large positive anomalies in the southern and central regions. The Chipman Domain, on the east side, consists of tonalites, mafic granulites, and granite, intruded by the Chipman dike swarm at ~ 1.9 Ga, where anomalies cut across mapped lithologic boundaries. Susceptibility measurements from both field and lab readings range over several orders of magnitude, from 1 × 10- 5 to 3 × 10- 1 SI, with higher values related to both mafic granulite and some tonalite samples. Remanence values also show considerable variability, from 0.1 mA/m to 90 A/m, with the weakest magnetization found in the Chipman dikes and the Fehr granite. Forty samples out of 89 have Koenigsberger ratios greater than 1, but low initial remanence limits its influence on anomalies. Hysteresis and low temperature measurements identify magnetite as the predominant iron oxide. This section of lower crustal rocks has paramagnetic granites and dikes, with ferromagnetic mafic granulites and bimodal tonalites, defined by geographic location.

  12. What can we learn from melt inclusions in migmatites and granulites?

    NASA Astrophysics Data System (ADS)

    Cesare, B.; Acosta-Vigil, A.; Bartoli, O.; Ferrero, S.

    2015-12-01

    With less than two decades of activity, research on melt inclusions (MI) in crystals from rocks that have undergone crustal anatexis - migmatites and granulites - is a recent addition to crustal petrology and geochemistry. Studies on this subject started with glassy inclusions in anatectic crustal enclaves in lavas, and then progressed to regionally metamorphosed and partially melted crustal rocks, where melt inclusions are normally crystallized into a cryptocrystalline aggregate (nanogranitoid). Since the first paper on melt inclusions in the granulites of the Kerala Khondalite Belt in 2009, reported and studied occurrences are already a few tens. Melt inclusions in migmatites and granulites show many analogies with their more common and long studied counterparts in igneous rocks, but also display very important differences and peculiarities, which are the subject of this review. Microstructurally, melt inclusions in anatectic rocks are small, commonly 10 μm in diameter, and their main mineral host is peritectic garnet, although several other hosts have been observed. Inclusion contents vary from glass in enclaves that were cooled very rapidly from supersolidus temperatures, to completely crystallized material in slowly cooled regional migmatites. The chemical composition of the inclusions can be analyzed combining several techniques (SEM, EMP, NanoSIMS, LA-ICP-MS), but in the case of crystallized inclusions the experimental remelting under confining pressure in a piston cylinder is a prerequisite. The melt is generally granitic and peraluminous, although granodioritic to trondhjemitic compositions have also been found. Being mostly primary in origin, inclusions attest for the growth of their peritectic host in the presence of melt. As a consequence, the inclusions have the unique ability of preserving information on the composition of primary anatectic crustal melts, before they undergo any of the common following changes in their way to produce crustal magmas

  13. Fluid evolution of the Hub Stock, Horní Slavkov-Krásno Sn-W ore district, Bohemian Massif, Czech Republic

    NASA Astrophysics Data System (ADS)

    Dolníček, Zdeněk; René, Miloš; Prochaska, Walter; Kovář, Michal

    2012-10-01

    The Horní Slavkov-Krásno Sn-W ore district is hosted by strongly altered Variscan topaz-albite granite (Krudum granite body) on the northwestern margin of the Bohemian Massif. We studied the fluid inclusions on greisens, ore pockets, and ore veins from the Hub Stock, an apical expression of the Krudum granite. Fluid inclusions record almost continuously the post-magmatic cooling history of the granite body from ˜500 to <50°C. Rarely observed highest-temperature (˜500°C) highest-salinity (˜30 wt.% NaCl eq.) fluid inclusions are probably the result of secondary boiling of fluids exsolved from the crystallizing magma during pressure release which followed hydraulic brecciation of the gneissic mantle above the granite cupola. The greisenization was related to near-critical low-salinity (0-7 wt.% NaCl eq.) aqueous fluids with low amount of CO2, CH4, and N2 (≤10 mol% in total) at temperatures of ˜350-400°C and pressures of 300-530 bar. Crush-leach data display highly variable and negatively correlated I/Cl and Br/Cl values which are incompatible with both orthomagmatic and/or metamorphic origin of the fluid phase, but can be explained by infiltration of surficial and/or sedimentary fluids. Low fluid salinity indicates a substantial portion of meteoric waters in the fluid mixture that is in accordance with previous stable isotope data. The post-greisenization fluid activity associated with vein formation and argillitization is characterized by decreasing temperature (<350 to <50°C), decreasing pressure (down to ˜50-100 bar), and mostly also decreasing salinity.

  14. UHT granulite-facies metamorphism in Rogaland, S Norway, is polyphase in nature

    NASA Astrophysics Data System (ADS)

    Laurent, Antonin; Duchene, Stéphanie; Bingen, Bernard; Seydoux-Guillaume, Anne-Magali; Bosse, Valérie

    2016-04-01

    Propensity of metamorphic assemblages to remain metastable after melt extraction complicates singularly the petrologist's task to discriminate between a single granulite-facies P-T path and a polyphase one. Using an integrated petrological and in-situ geochronological approach in key rock-samples, we reconstruct the pressure-temperature-time path of Sveconorwegian metamorphism across a 30 km-wide metamorphic gradient ranging from upper amphibolite facies to ultra-high temperature (UHT) granulite-facies in Rogaland, S. Norway. Thermodynamic modelling of phase equilibria in the Na2O-CaO-K2O-FeO-MgO-Al2O3-SiO2-H2O-Ti2O-O2 chemical system (PerpleX code) are carried out with an emphasis on moderately oxidized, spinel-bearing assemblages resulting from either garnet or sapphirine breakdown. Geochronological U-(Th)-Pb data acquired on both monazite (LA-ICP-MS) and zircon (SIMS) are complemented by minor- and trace-elements signatures of both minerals, to monitor REE distribution through time and to evaluate garnet apparition or demise. Coupling field, petrological and geochronological data lead to a polyphase metamorphic history, lasting about 100 My. The onset of regional granulite facies metamorphism at 1035 Ma is associated with the emplacement of large volumes of granitic magmas in the amphibolite to granulite facies transition zone. In the deeper part of the crustal section, localized sapphirine-bearing restitic lithologies testify to UHT temperatures (900‑920 °C). These conditions were reached at ca. 1010 Ma following a tight clockwise P-T path associated with minor exhumation (7 to 5.5 kbar) and subsequent cooling to 700 °C. A distinct thermal episode, initiated at ca. 950 Ma, reached UHT granulite-facies conditions with the intrusion of massif-type anorthosite plutons at ca. 930 Ma producing a 5-km wide aureole. The aureole is delimited by the presence of osumilite in high Fe-Al rocks yielding quantitative estimates of 900-950 °C at a maximum pressure of 5

  15. UHT granulite-facies metamorphism in Rogaland, S Norway, is polyphase in nature

    NASA Astrophysics Data System (ADS)

    Laurent, Antonin; Duchene, Stéphanie; Bingen, Bernard; Seydoux-Guillaume, Anne-Magali; Bosse, Valérie

    2016-04-01

    Propensity of metamorphic assemblages to remain metastable after melt extraction complicates singularly the petrologist's task to discriminate between a single granulite-facies P-T path and a polyphase one. Using an integrated petrological and in-situ geochronological approach in key rock-samples, we reconstruct the pressure-temperature-time path of Sveconorwegian metamorphism across a 30 km-wide metamorphic gradient ranging from upper amphibolite facies to ultra-high temperature (UHT) granulite-facies in Rogaland, S. Norway. Thermodynamic modelling of phase equilibria in the Na2O-CaO-K2O-FeO-MgO-Al2O3-SiO2-H2O-Ti2O-O2 chemical system (PerpleX code) are carried out with an emphasis on moderately oxidized, spinel-bearing assemblages resulting from either garnet or sapphirine breakdown. Geochronological U-(Th)-Pb data acquired on both monazite (LA-ICP-MS) and zircon (SIMS) are complemented by minor- and trace-elements signatures of both minerals, to monitor REE distribution through time and to evaluate garnet apparition or demise. Coupling field, petrological and geochronological data lead to a polyphase metamorphic history, lasting about 100 My. The onset of regional granulite facies metamorphism at 1035 Ma is associated with the emplacement of large volumes of granitic magmas in the amphibolite to granulite facies transition zone. In the deeper part of the crustal section, localized sapphirine-bearing restitic lithologies testify to UHT temperatures (900-920 °C). These conditions were reached at ca. 1010 Ma following a tight clockwise P-T path associated with minor exhumation (7 to 5.5 kbar) and subsequent cooling to 700 °C. A distinct thermal episode, initiated at ca. 950 Ma, reached UHT granulite-facies conditions with the intrusion of massif-type anorthosite plutons at ca. 930 Ma producing a 5-km wide aureole. The aureole is delimited by the presence of osumilite in high Fe-Al rocks yielding quantitative estimates of 900-950 °C at a maximum pressure of 5 kbar

  16. Extraction and carbon isotope analysis of CO 2 from scapolite in deep crustal granulites and xenoliths

    NASA Astrophysics Data System (ADS)

    Moecher, David P.; Valley, John W.; Essene, Eric J.

    1994-01-01

    Carbon isotope compositions of scapolite from granulite facies gneisses and lower crustal xenoliths document the composition and constrain the source of carbon in scapolite from the lower crust. CO 2 is extracted from scapolite without fractionating carbon isotopes by reaction with phosphoric acid at 25 or 75°C. Thus, partial yields of CO 2 from scapolite are sufficient for accurate carbon isotopic analysis. Isotopic compositions of coexisting scapolite and calcite in high-grade calc-silicate gneisses and marbles, and consideration of the crystal chemical environment of CO 3 in the scapolite structure, indicate little fractionation of 13C /12C between scapolite and calcite (0.1 ± 1.2%.) at equilibrium conditions of 650-800°C. The carbon isotope composition of CO 2 extracted from scapolite in twenty-nine samples of regional granulite facies gneisses, amphibolites, calc-silicate gneisses, and crustal xenoliths yield values of δ 13C that range from -10 to -1%. (PDB). High-grade marbles and graphitic paragneisses are precluded as major sources of carbon for scapolite in the high grade rocks analyzed in this study, as the former are isotopically enriched, and the latter isotopically depleted in 13C /12C relative to the range of isotopic compositions determined here. The δ 13C values for mafic granulites and amphibolites in granulite terranes composed of supracrustal sequences (-10.1 to -4.0%.) may reflect the isotopic composition of diagenetic carbonate present in their basaltic protoliths. The values of δ 13C for scapolite in mafic xenoliths and some granulite facies orthogneisses (-8.2 to -1.2%.) are consistent with crystallization of the scapolite from a mafic melt or derivation of CO 2 from mafic melts emplaced in the lower crust or upper mantle. The values of δ 13C for scapolites from calc-silicate gneisses and calc-silicate xenoliths (-10.0 to -2.9%.) may result from depletion of 13C /12C as a result of decarbonation of calcite-bearing protoliths during

  17. P-T history and geochemical characteristics of mafic granulites and charnockites from west of Periya, North Kerala, southern India

    NASA Astrophysics Data System (ADS)

    Prakash, D.; Chandra Singh, P.; Arima, M.; Singh, Triveni

    2012-11-01

    The study region forms the northern part of Kerala (south India) and constitutes part of granulite-facies rocks of the exhumed Proterozoic south Indian Granulite Terrain (SGT). The SGT consists of a large variety of rock types with a wide range of mineral parageneses and chemical compositions, namely charnockite, mafic granulite, gneiss, schist, anorthosite, granite and minor meta-sedimentary rocks. Garnet-bearing mafic granulites occur as small enclaves within charnockites. We report for the first time P-T constraints on the prograde path preceding peak metamorphism in the northernmost part of Kerala. An increase of the Mg, Fe and decrease of Ca and Mn contents from the core towards the rim of garnet in the mafic granulites suggest prograde garnet growth. The prograde path was followed by peak metamorphism at a temperature of c. 800 °C and a pressure of c. 7.5 kbar as computed by isopleths of XMg garnet, XCa garnet and XAn plagioclase. The resorption of garnet in various reaction textures and the development of spectacular orthopyroxene-plagioclase, biotite-quartz and hornblende-plagioclase symplectites characterize the subsequent stages of metamorphism. The PT path is characteristically T-convex suggesting an isothermal decompression path and reflects rapid uplift followed by cooling of a tectonically thickened crust. Diffusion modeling of Fe-Mg exchange between garnet and hornblende suggests a near-peak cooling rate of 10-70 °C/myr. Such cooling rates are too high to be accounted for by normal isostatic uplift and erosion and suggest that the terrain was tectonically exhumed. Charnockites are richer in SiO2 and lower in MgO and CaO when compared to mafic granulites. Their REE patterns are relatively flat and show prominent negative europium anomalies. The mafic granulites are metamorphosed tholeiitic basalts as revealed by major- and trace-element geochemistry.

  18. The Freyenstein Shear Zone - Implications for exhumation of the South Bohemian Batholith (Moldanubian Superunit, Strudengau, Austria)

    NASA Astrophysics Data System (ADS)

    Griesmeier, Gerit; Iglseder, Christoph; Konstantin, Petrakakis

    2016-04-01

    The Moldanubian superunit is part of the internal zone of the Variscan Orogen in Europe and borders on the Saxothuringian and Sudetes zones in the north. In the south, it is blanketed by the Alpine foreland molasse. Tectonically it is subdivided into the Moldanubian Nappes (MN), the South Bohemian Batholith (SBB) and the Bavarian Nappes. This work describes the ~ 500 m thick Freyenstein shear zone, which is located at the southern border of the Bohemian Massif north and south of the Danube near Freyenstein (Strudengau, Lower Austria). The area is built up by granites of Weinsberg-type, which are interlayered by numerous dikes and paragneisses of the Ostrong nappe system. These dikes include medium grained granites and finegrained granites (Mauthausen-type granites), which form huge intrusions. In addition, smaller intrusions of dark, finegrained diorites und aplitic dikes are observed. These rocks are affected by the Freyenstein shear zone und ductily deformed. Highly deformed pegmatoides containing white mica crystals up to one cm cut through the deformed rocks and form the last dike generation. The Freyenstein shear zone is a NE-SW striking shear zone at the eastern edge of the SBB. The mylonitic foliation is dipping to the SE with angles around 60°. Shear-sense criteria like clast geometries, SĆ structures as well as microstructures show normal faulting top to S/SW with steep (ca. 50°) angles. The Freyenstein shear zone records a polyphase history of deformation and crystallization: In a first phase, mylonitized mineral assemblages in deformed granitoides can be observed, which consist of pre- to syntectonic muscovite-porphyroclasts and biotite as well as dynamically recrystallized potassium feldspar, plagioclase and quartz. The muscovite porphyroclasts often form mica fishes and show top to S/SW directed shear-sense. The lack of syntectonic chlorite crystals points to metamorphic conditions of lower amphibolite-facies > than 450° C. In a later stage fluid

  19. The rare earth element potential of kaolin deposits in the Bohemian Massif (Czech Republic, Austria)

    NASA Astrophysics Data System (ADS)

    Höhn, S.; Frimmel, H. E.; Pašava, J.

    2014-12-01

    Four kaolin deposits in the Bohemian Massif were studied in order to assess the potential for the recovery of rare earth elements (REE) as by-products from the residue after extraction and refining of the raw kaolin. The behaviour of REE + Y during kaolinitization was found to be largely a function of pre-alteration mineralogy. In the examples studied, i.e. granite-derived deposits of Kriechbaum (Austria) and Božičany, and arkose-derived deposits of Kaznějov and Podbořany (all Czech Republic), the REE + Y are predominantly hosted by monazite which has remained unaffected by kaolinitization. The overall REE + Y content of the variably kaolinitized rocks is strongly dependent on their genesis. While ion adsorption plays only a minor role in the concentration of REE + Y in the studied kaolinitized rocks, the processing and refining of the raw kaolin leads to residues that are enriched in REE + Y by a factor of up to 40. The use of a magnetic separator and a hydrocyclone in the processing of the raw material can yield REE + Y contents of as much as 0.77 wt%. Although this value compares well with the REE + Y concentration in some potentially economic REE + Y projects elsewhere, the overall tonnage of the (REE + Y)-enriched residue is by far not sufficient to consider economic extraction of REE + Y as by-product. Our results are most probably applicable also to other kaolin deposits derived from the weathering of Hercynian basement granites elsewhere (e.g. in Saxonia and Bavaria, Germany). Overall, the potential for REE + Y production as by-product from kaolin mining has to be regarded as minimal.

  20. Flash flood in 1714 in the Bohemian-Moravian Highlands - Reconstructing a Catastrophe.

    NASA Astrophysics Data System (ADS)

    Elleder, Libor; Krejčí, Jakub; Šírová, Jolana

    2015-04-01

    Read against the backdrop of the past twenty years with their exceptional frequency of summer floods, records of historical flood events have become highly topical. Aside from the May flood of 1872, the flash flood that occurred at the turn of July and August 1714 in the Bohemian-Moravian Highlands is probably the most important case of its kind in the Czech lands, and may likely be ranked among the most notable occurrences of extreme weather even within the larger Central European context. Within the catchment basin of the Sázava River, the headwater level rose about three meters above the highest floods on the hydrological record and 1.5m above the highest historical flood-mark. Taking into account the time period - i.e., the beginning of the 18th century - some of the concurrent accounts of the flood are uncommonly detailed, containing not only a specification of the damage caused, but also high water mark figures and, at least in broad strokes, a record of the changing water levels over time. The flood caused tremendous material damage at the time, breaching e.g. about 70 fish ponds and destroying essentially all bridges; over 230 people were killed. It was revealed that the area of Žďárské vrchy (Žďár Hills) at the divide of the rivers Loučná, Chrudimka, Sázava, and Svratka which was impacted by the causative extreme precipitation may have measured 800 to 1000 square kilometers. Rough estimates of the headwater flow rate equal about four times current Q100 values. We therefore used the hydrological model Aqualog in order to determine whether an event of this scope was at all realistic. The goal was to assess whether it was realistically possible that precipitation may have been of such scope as to trigger a hydrological response of this intensity.

  1. Reintroduction of gold, other chalcophile elements and LILE during retrogression of depleted granulite, Tromøy, Norway

    NASA Astrophysics Data System (ADS)

    Cameron, Eion M.

    1993-02-01

    Several metamorphic and magmatic events were associated with the Sveconorwegian orogeny (˜ 1.1 Ga) that affected the Bamble shear belt, south Norway. Among the most important were (1) granuliteto amphibolite-facies metamorphism of the entire belt; (2) intrusion of mafic dykes ("hyperites"), followed by their localized metamorphism to amphibolite; (3) intrusion of granitic sheets, which in granulite terrane caused rehydration and retrogression. Previous studies have shown that rocks from across the belt metamorphosed to amphibolite and granulite grade during event (1) are strongly depleted in Au, Sb and As; while some granulites are also depleted in Rb, Cu and S. Gold and chalcophile elements were also lost during (2) amphibolization of hyperites. This paper is concerned with event (3), at which time the granulites had been uplifted and cooled. H 2OCO 2 fluids, at least in part derived from the granitic magma, caused localized rehydration and retrogression of granulite. This was accompanied by the variable reintroduction of the same elements (Au, As, Sb, Cu, S and Rb) that had earlier been depleted. The nature of the reintroduction of Au and other elements has relevance to the origin of mesothermal gold deposits.

  2. Long-lived high-temperature granulite-facies metamorphism in the Eastern Himalayan orogen, south Tibet

    NASA Astrophysics Data System (ADS)

    Zhang, Zeming; Xiang, Hua; Dong, Xin; Ding, Huixia; He, Zhenyu

    2015-01-01

    The Namche Barwa Complex exposed in the Eastern Himalayan Syntaxis, south Tibet, underwent high-pressure (HP) and high-temperature (HT) granulite-facies metamorphism and associated anatexis. The HP pelitic granulites contain garnet, kyanite, sillimanite, cordierite, biotite, quartz, plagioclase, K-feldspar, spinel, ilmenite and graphite. These minerals show composite reaction texture and varying chemical compositions and form four successive mineral assemblages. Phase equilibrium modeling constrains the P-T conditions of 10-12 kbar and 550-700 °C for the prograde stage, 13-16 kbar and 840-880 °C for the peak-metamorphic stage, and 5-6 kbar and 830-870 °C for the late retrograde stage, indicating that the HP granulites recorded a clockwise P-T path involving the early heating burial and anatexis through dehydration melting of both muscovite and biotite, and the late isothermal decompression and gradual melt crystallization under HT granulite-facies conditions. The zircon U-Pb dating reveals that the HT granulite-facies metamorphism probably initiated at ca. 40 Ma, and lasted to ca. 8 Ma. Therefore, the present study provides robust evidence for a long-lived HT metamorphism and associated anatexis in the deeply buried Indian continent and important constraints on the leucogranite generation and tectonic evolution of the Himalayan orogen.

  3. Lunar highland meteorite Dhofar 026 and Apollo sample 15418: Two strongly shocked, partially melted, granulitic breccias

    USGS Publications Warehouse

    Cohen, B. A.; James, O.B.; Taylor, L.A.; Nazarov, M.A.; Barsukova, L.D.

    2004-01-01

    Studies of lunar meteorite Dhofar 026, and comparison to Apollo sample 15418, indicate that Dhofar 026 is a strongly shocked granulitic breccia (or a fragmental breccia consisting almost entirely of granulitic breccia clasts) that experienced considerable post-shock heating, probably as a result of diffusion of heat into the rock from an external, hotter source. The shock converted plagioclase to maskelynite, indicating that the shock pressure was between 30 and 45 GPa. The post-shock heating raised the rock's temperature to about 1200 ??C; as a result, the maskelynite devitrified, and extensive partial melting took place. The melting was concentrated in pyroxene-rich areas; all pyroxene melted. As the rock cooled, the partial melts crystallized with fine-grained, subophitic-poikilitic textures. Sample 15418 is a strongly shocked granulitic breccia that had a similar history, but evidence for this history is better preserved than in Dhofar 026. The fact that Dhofar 026 was previously interpreted as an impact melt breccia underscores the importance of detailed petrographic study in interpretation of lunar rocks that have complex textures. The name "impact melt" has, in past studies, been applied only to rocks in which the melt fraction formed by shock-induced total fusion. Recently, however, this name has also been applied to rocks containing melt formed by heating of the rocks by conductive heat transfer, assuming that impact is the ultimate source of the heat. We urge that the name "impact melt" be restricted to rocks in which the bulk of the melt formed by shock-induced fusion to avoid confusion engendered by applying the same name to rocks melted by different processes. ?? Meteoritical Society, 2004.

  4. An occurrence of metastable cristobalite in high-pressure garnet Granulite

    USGS Publications Warehouse

    Darling, R.S.; Chou, I.-Ming; Bodnar, R.J.

    1997-01-01

    High-pressure (0.8 gigapascals) granulite facies garnet from Gore Mountain, New York, hosts multiple solid inclusions containing the low- pressure silica polymorph cristobalite along with albite and minor ilmenite. Identification of cristobalite is based on Raman spectra, electron microprobe analysis, and microthermometric measurements on the ??/?? phase transformation. The cristobalite plus albite inclusions may have originated as small, trapped samples of hydrous sodium-aluminum-siliceous melt. Diffusive loss of water from these inclusions under isothermal, isochoric conditions may have resulted in a large enough internal pressure decrease to promote the metastable crystallization of cristobalite.

  5. Geo-thermometry and barometry in the southern Blue Ridge crustal section: Evidence for tectonic granulites

    SciTech Connect

    Eckert, J.O. Jr. )

    1993-03-01

    The study of Ramberg and DeVore established the framework within which the Mg-Fe[sup 2+] distribution between coexisting minerals, specifically olivine and Opx, could be calibrated as a thermometer. Experimentally calibrated thermobarometric systems applicable to high-grade rocks include Grt-pyroxene assemblages. Grt-Opx and Grt-Cpx thermometry apply the theory established by Ramberg and DeVore. Barometry, based on the Ca distribution in Grt-Opx Plg-Qtz (GAPES) and Grt-Cpx-Plg-Qtz (GADS) assemblages, was improved by solution calorimetry on synthetic Mg end members to produce reliable enthalpies of reaction. The resultant barometric expressions are: P = 3.47 + 0.01307T + 0.003504T lnK[sub GAPES] ([plus minus]1.55 kbars) (GAPES) and P = 2.60 + 0.01718T + 0.003596T lnK[sub GADS] ([plus minus]1.90 kbars) (GADS). Current work is focused on reversing the Mg-Fe[sup 2+] exchange between Grt and Opx. In the SW North Carolina Blue Ridge, where Grt-Opx and Grt-Cpx T calculations yield plausible granulite-facies temperature ([>=] 700C), P-T conditions calculated with these pyroxene-based reactions generally agree with calculations using equilibria in pelitic rocks (T from Grt-Bt; P from Grt-Plg-Al[sub 2]SiO[sub 5]-Qtz, GASP). Grt-Opx/Cpx systems allow P-T estimation only in the granulite and eclogite facies; Grt-Bt and GASP permit P-T calculations throughout this amphibolite to granulite facies transition. Results from metapelites indicate increasing P with T (positive dP/dT); this implies a depth-zone array. This progression thus represents a Paleozoic (Taconian ) middle-to-lower crustal cross section, the southern Blue Ridge crustal section (SBRCS). The SBRCS P-T array shows greater dP/dT than would be likely near an external heat source. These high-grade rocks likely heated after crustal thickening, forming as tectonic granulites.

  6. Fluid heterogeneity during granulite facies metamorphism in the Adirondacks: stable isotope evidence

    USGS Publications Warehouse

    Valley, J.W.; O'Neil, J.R.

    1984-01-01

    The preservation of premetamorphic, whole-rock oxygen isotope ratios in Adirondack metasediments shows that neither these rocks nor adjacent anorthosites and gneisses have been penetrated by large amounts of externally derived, hot CO2-H2O fluids during granulite facies metamorphism. This conclusion is supported by calculations of the effect of fluid volatilization and exchange and is also independently supported by petrologic and phase equilibria considerations. The data suggest that these rocks were not an open system during metamorphism; that fluid/rock ratios were in many instances between 0.0 and 0.1; that externally derived fluids, as well as fluids derived by metamorphic volatilization, rose along localized channels and were not pervasive; and thus that no single generalization can be applied to metamorphic fluid conditions in the Adirondacks. Analyses of 3 to 4 coexisting minerals from Adirondack marbles show that isotopic equilibrium was attained at the peak of granulite and upper amphibolite facies metamorphism. Thus the isotopic compositions of metamorphic fluids can be inferred from analyses of carbonates and fluid budgets can be constructed. Carbonates from the granulite facies are on average, isotopically similar to those from lower grade or unmetamorphosed limestones of the same age showing that no large isotopic shifts accompanied high grade metamorphism. Equilibrium calculations indicate that small decreases in ??18O, averaging 1 permil, result from volatilization reactions for Adirondack rock compositions. Additional small differences between amphibolite and granulite facies marbles are due to systematic lithologie differences. The range of Adirondack carbonate ??18O values (12.3 to 27.2) can be explained by the highly variable isotopic compositions of unmetamorphosed limestones in conjunction with minor 18O and 13C depletions caused by metamorphic volatilization suggesting that many (and possibly most) marbles have closely preserved their

  7. Garnet granulite xenoliths from the Northern Baltic shield- The underplated lower crust of a palaeoproterozoic large igneous province

    USGS Publications Warehouse

    Kempton, P.D.; Downes, H.; Neymark, L.A.; Wartho, J.A.; Zartman, R.E.; Sharkov, E.V.

    2001-01-01

    Garnet granulite facies xenoliths hosted in Devonian lamprophyres from the Kola Peninsula are interpreted to represent the high-grade metamorphic equivalents of continental flood tholeiites, emplaced into the Baltic Shield Archaean lower crust in early Proterozoic time. Geochronological data and similarities in major and trace element geochemistry suggest that the xenoliths formed during the same plume-related magmatic event that created a widespread Palaeoproterozoic large igneous province (LIP) at 2.4-2.5 Ga. They are, thus, the first samples of the lower crust of a Palaeo-proterozoic LIP to be studied in petrological detail. The suite includes mafic granulites (gar + cpx + rutile ?? plag ?? opx ?? phlog ?? amph), felsic granulites (plag + gar + cpx + rutile ?? qtz ?? Kspar ?? phlog ?? amph) and pyroxenites (?? phlog ?? amph), but mafic garnet granulites predominate. Although some samples are restites, there is no evidence for a predominance of magmatic cumulates, as is common for Phanerozoic lower-crustal xenolith suites. Metasediments are also absent. Phlogopite and/or amphibole occur in xenoliths of all types and are interpreted to be metasomatic in origin. The K-rich metasomatic event occurred at ?????0 Ga, and led to substantial enrichment in Rb, K, LREE/HREE, Th/U, Th/Pb and, to a lesser extent, Nb and Ti. The fluids responsible for this metasomatism were probably derived from a second plume that arrived beneath the region at this time. Evidence for partial melting of mafic crust exists in the presence of migmatitic granulites. The timing of migmatization overlaps that of metasomatism, and it is suggested that migmatization was facilitated by the metasomatism. The metamorphism, metasomatism and migmatization recorded in the Kola granulite xenoliths may be representative of the processes responsible for converting Archaean LIP-generated proto-continents into continental crust.

  8. Nd isotopic systematics and chemistry of Central Australian sapphirine granulites: an example of rare earth element mobility

    NASA Astrophysics Data System (ADS)

    Windrim, D. P.; McCulloch, M. T.; Chappell, B. W.; Cameron, W. E.

    1984-09-01

    Lower Proterozoic sapphirine-bearing and associated granulites from Central Australia exhibit the greatest range of present-day 143Nd/ 144Nd ratios (∈ Nd(O)= -26.5 to +112.3) yet reported for rocks believed to be cogenetic. The Nd isotopic data and REE abundances of these rocks demonstrate extreme fractionation of the rare earths during the formation of stratiform Cu sbnd Pb sbnd Zn sulfide deposits with which they are closely associated. Field relationships, petrography and chemistry of the sapphirine granulites suggest that their protoliths comprised chlorite-rich rocks which were generated by hydrothermal alteration of a range of rock types prior to metamorphism; calculations employing REE abundances of the sapphirine granulites and associated rocks, combined with bulk solid-fluid distribution coefficient data yield high fluid/rock ratios, consistent with a pre-metamorphic hydrothermal origin for the unusual REE patterns. The Sm sbnd Nd data for these rocks define an age of 1760±75Ma, which is significantly younger than the crust formation age of the terrain ( 2070±125Ma) but indistinguishable from the Rb sbnd Sr whole rock age for granulite facies metamorphism (1790±35Ma). These data are interpreted in terms of major hydrothermal fractionation of the rare earths shortly (perhaps tens of millions of years) before granulite facies metamorphism, followed by redistribution of Nd isotopes or small fractionations of the Sm/Nd ratio during the granulite facies event, and possibly also during intense retrogression which reset Rb sbnd Sr whole rock and U sbnd Pb zircon and monazite systematics at about 1700 Ma.

  9. Early Cretaceous vein-related garnet granulite in Fiordland, southwest New Zealand: a case for infiltration of mantle-derived CO2-rich fluids

    USGS Publications Warehouse

    Bradshaw, J.Y.

    1989-01-01

    Regionally extensive two-pyroxene granulite facies orthogneisses of Early Cretaceous age in Fiordland, southwest New Zealand, are criss-crossed by garnet-bearing feldspathic veins (and dikes) having associated marginal reaction zones of garnet granulite. The two-pyroxene granulites resulted from fluid-absent metamorphism of a suite of synkinematic primary anhydrous intrusions. Subsequent restricted formation of garnet granulite in feldspathic compositions, and locally eclogite in ultramafic compositions, proceeded chiefly via reactions involving hornblende breakdown, and occurred in response to sharply increased load pressure and local lowering of water activity. Fluid infiltration occurred at or near peak metamorphic pressure (~12 kbar at 650-700??C). Granulite metamorphism was of short duration (<20 m.y.) and accompanied tectonic thickening in a subduction-related magmatic arc. -from Author

  10. Lead isotopes and the origin of granulite and eclogite inclusions in deep-seated pipes

    USGS Publications Warehouse

    Lovering, J.F.; Tatsumoto, M.

    1968-01-01

    The isotopic composition of lead and the concentrations of lead, uranium, and thorium in Delegate basic pipes from Australia and in South African kimberlite pipes have been determined. The observed 238U/204Pb and observed 232Th/238U of eclogite inclusions in the pipes range from 2.9 to 18.7 and from 3.5 to 5.9, respectively. This result as well as the isotopic composition of lead suggests that the upper mantle is chemically heterogeneous with regard to the trace elements. Pyrochemically extracted leads from eclogite inclusions in the Delegate basic pipes and in a South African kimberlite pipe appear to be different in isotopic compositions from leads extracted from the host rock (matrix). These data are consistent with the hypothesis that the eclogitic inclusions in deep-seated pipes are of "accidental" origin and represent upper mantle materials caught up in the host materials during their intrusion. Lead extracted from a two-pyroxene granulite inclusion in one of the Delegate pipes has an isotopic composition indistinguishable from lead in the host rock. This observation is consistent either with a "cognate" origin for the granulite inclusion or with a modified "accidental" origin in which the isotopic composition of the original lead in the inclusion has been contaminated by lead from the host magma. Other evidence would indicate that an "accidental" origin be preferred. ?? 1968.

  11. Pressure-temperature conditions in granulite facies rocks of the northern Canadian Shield, Arctic Canada

    SciTech Connect

    Frisch, T.

    1985-01-01

    The northernmost part of the Churchill Structural Province of the Canadian Shield, underlying 60,000 km/sup 2/ of southeastern Ellesmere Island, Coburg Island and eastern Devon Island, consists of granulite facies metasedimentary, meta-igneous and plutonic intrusive rocks 2400 to 1900 m.y. old. Garnet+pyroxene+plagioclase of quartzofeldspathic gneisses from Ellesmere and Coburg islands indicate pressures, at 750/sup 0/C, ranging from greater than or equal to 6 to approx. 4kb; the lower pressures are derived largely, but not solely, from rim compositions. Similar rocks from Devon Island consistently indicate higher pressures of 6 to 7 kb. Garnet and plagioclase cores in sillimanite+cordierite-rich pelitic gneisses give pressures between 5 and 6.5 kb at 750/sup 0/C, the highest pressures being found in Devon Island rocks. Orthopyroxene+cordierite symplectites around garnet in magnesian metapelites indicate pressures under 4 kb at 650/sup 0/C. All cordierite is clearly of retrograde origin, having formed as a result of decompression during uplift, but even the highest pressures determined fall below the stability limit of cordierite in metapelites. Circumstantial evidence exists for the former stable coexistence of orthopyroxene+sillimanite, which would attest to pressures well in excess of 7 kb, but existing geobarometric equilibria have been strongly influenced by retrograde processes. Retrograde pressure-temperature conditions may well predominate in many granulite terranes but are not always recognized due to a scarcity of suitable mineral assemblages.

  12. Soil Collembola communities within Plešné Lake and Čertovo Lake catchments, the Bohemian Forest

    NASA Astrophysics Data System (ADS)

    Čuchta, Peter

    2016-04-01

    The soil Collembola communities were studied for three years in disturbed spruce forest stands in the catchments areas of Čertovo and Plešné Lakes in the Bohemian Forest, Czech Republic. The study was focused on the impact of the windthrow, bark beetle outbreak damage and consecutive changes in the forest stands including soil environment. Four different treatments were selected for the study on both study areas: undamaged (control) forest stands, "dead" forest stands damaged by bark beetle, slightly managed windthrown forest stands left for the natural succession, and freshly harvested windthrown stands. After two years of research a total of 7,294 Collembola specimens were recorded belonging to 93 species. We recorded the highest collembolan abundance and species richness in the reference stands within catchments of both lakes, while both given parameters were considerably lower in harmed forest stands. To summarize, the disturbance led to a general decrease of Collembola communities.

  13. Cross-border radon index map 1:100 000 Lausitz - Jizera - Karkonosze - Region (northern part of the Bohemian Massif).

    PubMed

    Barnet, Ivan; Pacherová, Petra; Preusse, Werner; Stec, Bartosz

    2010-10-01

    The first cross-border map describing the radon (Rn) risk from bedrock was assembled in the northern part of the Bohemian Massif at a scale 1:100 000. The map covers the area of Lausitz (Germany), Karkonosze (Czech Republic and Poland) and Jizera (Czech Republic). The map is based on 818 measurements of soil gas Rn in rock types of Precambrian to Mesozoic age with variable geology. Geographic information system (GIS) processing enabled a good coincidence of soil gas Rn concentrations between data from all three countries in lithologically adjacent rock types as well as the direct correlation to georeferenced indoor Rn values, which was tested using the Czech indoor Rn data. The method of data processing can contribute to assembling the European Geogenic Radon Map. PMID:20022148

  14. Pan-African granulites of central Dronning Maud Land and Mozambique: A comparison within the East-African-Antarctic orogen

    USGS Publications Warehouse

    Engvik, A.K.; Elevevold, S.; Jacobs, J.; Tveten, E.; de Azevedo, S.; Njange, F.

    2007-01-01

    Granulite-facies metamorphism is extensively reported in Late Neoproterozoic/Early Palaeozoic time during formation of the East-African-Antarctic orogen (EAAO). Metamorphic data acquired from the Pan-African orogen of central Dronning Maud Land (cDML) are compared with data from northern Mozambique. The metamorphic rocks of cDML are characterised by Opx±Grt-bearing gneisses and Sil+Kfs-bearing metapelites which indicate medium-P granulite-facies metamorphism. Peak conditions, which are estimated to 800-900ºC at pressures up to 1.0 GPa, were followed by near-isothermal decompression during late Pan-African extension and exhumation. Granulite-facies lithologies are widespread in northern Mozambique, and Grt+Cpx-bearing assemblages show that high-P granulite-facies conditions with PT reaching 1.55 GPa and 900ºC were reached during the Pan-African orogeny. Garnet is replaced by symplectites of Pl+Opx+Mag indicating isothermal decompression, and the subsequent formation of Pl+amphibole-coronas suggests cooling into amphibolite facies. It is concluded that high-T metamorphism was pervasive in EAAO in Late Neoproterozoic/Early Paleozoic time, strongly overprinting evidences of earlier metamorphic assemblages.

  15. Metamorphic history of LP/HT migmatites from the Bavarian Unit (Bohemian Massif)

    NASA Astrophysics Data System (ADS)

    Sorger, Dominik; Hauzenberger, Christoph; Linner, Manfred; Iglseder, Christoph

    2016-04-01

    Granulite facies migmatites are commonly observed in the Bavarian Unit which were formed during a late Variscan (post 330 Ma) LP-HT overprint. This event is related to a delamination of mantle lithosphere and subsequent asthenospheric upwelling. Most of these rocks underwent high degrees of melting forming meta- and diatexites. Former work in the Sauwald area, Upper Austria, by Tropper et al. (2006) determined metamorphic conditions of 700-800°C and 0.4-0.5 Gpa. In this study samples were taken along the (1) Danube valley (west of Linz), from the (2) Lichtenberg area (north of Linz), the (3) Bad Leonfelden area (west of the Rodl Fault) and the (4) Sauwald area (south of the river Danube). Biotite and plagioclase bearing migmatite is very common and occurs all over the investigated area. These rocks are the product of intensive melting (anatexite) and formed at conditions of ~650-700°C and 0.25-0.45 Gpa. Scarce outcrops of garnet bearing Al-rich migmatitic metapelites occur along the Danube valley. The formation of the migmatitc texture with well-developed leucosomes (K-feldspar, plagioclase, quartz) and melanosomes (garnet, cordierite, sillimanite, spinel, ilmenite, ± biotite) indicate high temperature metamorphism. Most of the garnet grains show a homogenous iron-rich composition and form generally an almandine-pyrope (Xalm=0.78-0.80, Xprp=0.16-0.18) solid solution with minor contents of grossular and spessartine (Xgrs=0.028-0.032, Xsps=0.020-0.024). Large garnet porphyroblasts (up to 1cm in size) display a distinct chemical zoning, especially in grossular component. Elevated homogeneous grossular content in the core is followed discontinously by low grossular content at the rim indicating a two stage growth. Garnet core and rim also display different mineral inclusions. Thermobarometric calculations using garnet core compositions with inclusions and garnet rim compositions with matrix phases as well as pseudosection calculations allow the reconstruction of a P

  16. Evaluation of Water Use Efficiency of Short Rotation Poplar Coppice at Bohemian-Moravian Highlands

    NASA Astrophysics Data System (ADS)

    Hlaváčová, Marcela; Fischer, Milan; Mani Tripathi, Abhishek; Orság, Matěj; Trnka, Miroslav

    2015-04-01

    The water availability of the locality constitutes one of the main constraint for short rotation coppices grown on arable land. As a convenient characteristic assessing how the water use is coupled with the biomass yields, so called water use efficiency (WUE) is proposed. One method of water use efficiency determination is presented within this study. The study was carried out at short rotation poplar coppice (poplar clone J-105) at the Test Station Domanínek, Ltd. at Bohemian-Moravian Highlands during the growing season 2013. Diameters at breast height (DBH) were measured for 16 sample trees where sap flow measuring systems (Granier's Thermal Dissipation Probe, TDP) were installed. TDP outputs are expressed as temperature differences (ΔT) between the heated and non-heated probes. Estimation of sap flux density (Fd) by the Granier method relies on the measurement of temperature difference (ΔT). Determination of maximum temperature difference (ΔTmax) is fundamental for sap flux density (Fd) calculation. Although ΔTmax can be theoretically defined as ΔT at Fd = 0, many factors may prevent the occurrence of the zero flow state, such as night-time water movement for new growth (vegetative or reproductive) or water loss from the canopy due to high vapour pressure deficit (VPD). Therefore, the VPD condition was established for determination of ΔTmax. VPD condition was established as follows: VPD reaching values 0.2 at least 6 hours during night (from 21 p. m. to 3 a. m. and when the condition was fullfilled, the value at 3 a. m. was taken) because it is a supposed time after that the tree has no transpiration. The programmable part of Mini 32 software (www.emsbrno.cz) was used for application of the script establishing ΔTmax values under this VPD condition. Nevertheless, another script was applied on ΔT data set to determination of ΔTmax values for every night at 3 a. m. (as this is when ΔT should be at its daily maximum) without VPD condition restriction for

  17. Insights into the Crustal Structure and Geodynamic Evolution of the Southern Granulite Terrain, India, from Isostatic Considerations

    NASA Astrophysics Data System (ADS)

    Kumar, Niraj; Singh, A. P.; Singh, B.

    2011-10-01

    The Southern Granulite Terrain of India, formed through an ancient continental collision and uplift of the earth's surface, was accompanied by thickening of the crust. Once the active tectonism ceased, the buoyancy of these deep crustal roots must have supported the Nilgiri and Palani-Cardamom hills. Here, the gravity field has been utilized to provide new constraints on how the force of buoyancy maintains the state of isostasy in the Southern Granulite Terrain. Isostatic calculations show that the seismically derived crustal thickness of 43-44 km in the Southern Granulite Terrain is on average 7-8 km more than that required to isostatically balance the present-day topography. This difference cannot be solely explained applying a constant shift in the mean sea level crustal thickness of 32 km. The isostatic analysis thus indicates that the current topography of the Southern Granulite Terrain is overcompensated, and about 1.0 km of the topographic load must have been eroded from this region without any isostatic readjustment. The observed gravity anomaly, an order of magnitude lower than that expected (-125 mGal), however, shows that there is no such overcompensation. Thermal perturbations up to Pan-African, present-day high mantle heat flow and low Te together negate the possible resistance of the lithosphere to rebound in response to erosional unloading. To isostatically compensate the crustal root, compatible to seismic Moho, a band of high density (2,930 kg m-3) in the lower crust and low density (3,210 kg m-3) in the lithospheric mantle below the Southern Granulite Terrain is needed. A relatively denser crust due to two distinct episodes of metamorphic phase transitions at 2.5 Ga and 550 Ma and highly mobilized upper mantle during Pan-African thermal perturbation reduced significantly the root buoyancy that kept the crust pulled downward in response to the eroded topography.

  18. Dating High Temperature Mineral Fabrics in Lower Crustal Granulite Facies Rocks

    NASA Astrophysics Data System (ADS)

    Stowell, H. H.; Schwartz, J. J.; Tulloch, A. J.; Klepeis, K. A.; Odom Parker, K.; Palin, M.; Ramezani, J.

    2015-12-01

    Granulite facies rocks may record strain that provides a record of compressional and/or extensional crustal events in hot orogenic cores and the roots of magmatic arcs. Although the precise timing of these events is important for constructing tectonic histories, it is often difficult to determine due to uncertain relationships between isotopic signatures, mineral growth, and textural features that record strain. In addition, there may be large uncertainties in isotope data due to intracrystalline diffusion and multiple crystallization events. L-S tectonites in lower crustal rocks from Fiordland, NZ record the early stages of extensional collapse of thickened magmatic arc crust. The precise age of these fabrics is important for constraining the timing of extension that led to opening of the Tasman Sea. High temperature granulite facies L-S fabrics in garnet reaction zones (GRZ) border syn- to post-deformational leucosomes. U-Pb zircon, Lu-Hf garnet, and Sm-Nd garnet ages, and trace elements in these phases indicate the complexity of assigning precise and useful ages. Zircon have soccer ball morphology with patchy and sector zoned CL. Zircon dates for igneous host and adjacent GRZ range over ca. 17 Ma. 236U-208Pb LA-ICP-MS are 108-125 Ma, N=124 (host & GRZ); however, chemical abrasion (CA) shifts GRZ dates ca. 2 Ma older. 236U-208Pb SHRIMP-RG dates cluster in 2 groups: 118.5±0.8 Ma, N=23 and 111.0±0.8 Ma, N=6. CA single crystal TIMS dates also fall into 2 groups: 117.6±0.1 Ma, N=4 and 116.6±0.2 Ma N=4. Garnet isochron ages determined from coarse garnet selvages adjacent to leucosomes range from 112.8±2.2 (147Sm-143Nd, 10 pts.) to 114.8±3.5 (177Lu-176Hf, 6 pts.) Ma. Zircon dates from all methods show ranges (>10 Ma) and 2 distinct populations. Host and GRZ zircon cannot be readily distinguished by age, lack younger rims, but have distinct Th/U trends and Eu/Eu* vs. Hf ratios. Difference in zircon trace element composition indicates either early leucosome

  19. Mid-Paleozoic age of granitoids in enclaves within early Cretaceous granulites, Fiordland, southwest New Zealand

    USGS Publications Warehouse

    Bradshaw, J.Y.; Kimbrough, D.L.

    1991-01-01

    Orthogneisses of granite, quartz monzonite, monzonite, and tonalite, occur locally as isolated enclaves within the Early Cretaceous granulite terrain (Western Fiordland Orthogneiss - WFO). Discordant U-Pb zircon isotopic data (seven fractions) from four granitoid samples from enclaves at George Sound, define an upper intecept age of 341??34 Ma that is interpreted as approximating the time of formation of the granitoid suite. The lower intercept age of 93??37 Ma is interpreted as approximating the time of zircon isotopic disturbance by major episodic Pb loss. The low 87Sr/ 86Sr initial ratio indicates that these mid-Paleozoic granitoids were derived from an isotopically primitive source. The granitoid enclaves within WFO show influences of several different sources. The granitoids provide evidence linking WFO to a mid-Palaeozoic country rock similar to the central Fiordland metasediments. -from Authors

  20. Crustal evolution and the eclogite to granulite phase transition in xenoliths from the West African Craton

    NASA Technical Reports Server (NTRS)

    Haggerty, S. E.; Hills, D. V.; Toft, P. B.

    1988-01-01

    A suite of eclogite and granulite facies xenoliths from kimberlite pipes in the Archean Man Shield of West Africa is described. The xenoliths include lithologies ranging in composition from komatiite to anorthosite and appear to be geochemically, petrologically, and geophysically related. The suite may represent fractionation of felsic material separated from ancient mantle and added to early Archean crust. The samples can be used to define a xenolith geotherm, which may represent an ancient episode of high heat flow. The samples also imply that the crust-mantle boundary is a gradational and possibly interlayered geochemical, mineralogical, and seismic transition. It is speculated that the depleted subcontinental mantle required by diamond bearing coalescence of smaller depletion cells formed by extraction of ancient crustal components. These depleted zones are surrounded by fertile asthenospheric mantle, which may have given rise to later flood basalts such as the Karroo and Parana Provinces.

  1. Ultrahigh temperature deformation microstructures in felsic granulites of the Napier Complex, Antarctica

    NASA Astrophysics Data System (ADS)

    Lund, Majbritt D.; Piazolo, Sandra; Harley, Simon L.

    2006-12-01

    Detailed electron microscope and microstructural analysis of two ultrahigh temperature felsic granulites from Tonagh Island, Napier Complex, Antarctica show deformation microstructures produced at ˜ 1000 °C at 8-10 kbar. High temperature orthopyroxene (Al ˜7 wt.% and ˜ 11 wt.%), exhibits crystallographic preferred orientation (CPO) and frequent subgrain boundaries which point to dislocation creep as the dominating deformation mechanism within opx. Two different main slip systems are observed: in opx bands with exclusively opx grains containing subgrain boundaries with traces parallel to [010] and a strong coupling of low angle misorientations (2.5°-5°) with rotation axes parallel to [010] the dominating slip system is (100)[001]. Isolated opx grains and grain clusters of 2-5 grains embedded in a qtz-fsp matrix show an additional slip system of (010)[001]. The latter slip system is harder to activate. We suggest that differences in the activation of these slip systems is a result of higher differential stresses imposed onto the isolated opx grains and grain clusters. In contrast to opx, large qtz grains (up to 200 μm) show random crystallographic orientation. This together with their elongate and cuspate shape and the lack of systematic in the rotation axes associated with the subgrain boundaries is consistent with diffusion creep as the primary deformation mechanism in quartz. Our first time detailed microstructural observations of ultrahigh temperature and medium to high pressure granulites and their interpretation in terms of active deformation mechanisms give some insight into the type of rheology that can be expect at lower crustal conditions. If qtz is the mineral phase governing the rock rheology, Newtonian flow behaviour is expected and only low differential stress can be supported. However, if the stress supporting mineral phase is opx, the flow law resulting from dislocation creep will govern the rheology of the rock unit; hence, an exponential

  2. The systematics and paleobiogeographic significance of Sub-Boreal and Boreal ammonites (Aulacostephanidae and Cardioceratidae) from the Upper Jurassic of the Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Hrbek, Jan

    2014-10-01

    Upper Jurassic marine deposits are either rarely preserved due to erosion or buried under younger sediments in the Bohemian Massif. However, fossil assemblages from a few successions exposed in northern Bohemia and Saxony and preserved in museum collections document the regional composition of macro-invertebrate assemblages and thus provide unique insights into broad-scale distribution and migration pathways of ammonites during the Late Jurassic. In this paper, we focus on the systematic revision of ammonites from the Upper Oxfordian and Lower Kimmeridgian deposits of northern Bohemia and Saxony. The ammonites belong to two families (Aulacostephanidae and Cardioceratidae) of high paleobiogeographic and stratigraphic significance. Six genera belong to the family Aulacostephanidae (Prorasenia, Rasenia, Eurasenia, Rasenioides, Aulacostephanus, Aulacostephanoides) and one genus belongs to the family Cardioceratidae (Amoeboceras). They show that the Upper Jurassic deposits of the northern Bohemian Massif belong to the Upper Oxfordian and Lower Kimmeridgian and paleobiogeographically correspond to the German-Polish ammonite branch with the geographical extent from the Polish Jura Chain to the Swabian and Franconian Alb. Therefore, the occurrences of ammonites described here imply that migration pathway connecting the Polish Jura Chain with habitats in southern Germany was located during the Late Oxfordian and Early Kimmeridgian in the Bohemian Massif.

  3. Cenozoic volcanism in the Bohemian Massif in the context of P- and S-velocity high-resolution teleseismic tomography of the upper mantle

    NASA Astrophysics Data System (ADS)

    Plomerová, Jaroslava; Munzarová, Helena; Vecsey, Luděk.; Kissling, Eduard; Achauer, Ulrich; Babuška, Vladislav

    2016-08-01

    New high-resolution tomographic models of P- and S-wave isotropic-velocity perturbations for the Bohemian upper mantle are estimated from carefully preprocessed travel-time residuals of teleseismic P, PKP and S waves recorded during the BOHEMA passive seismic experiment. The new data resolve anomalies with scale lengths 30-50 km. The models address whether a small mantle plume in the western Bohemian Massif is responsible for this geodynamically active region in central Europe, as expressed in recurrent earthquake swarms. Velocity-perturbations of the P- and S-wave models show similar features, though their resolutions are different. No model resolves a narrow subvertical low-velocity anomaly, which would validate the "baby-plume" concept. The new tomographic inferences complement previous studies of the upper mantle beneath the Bohemian Massif, in a broader context of the European Cenozoic Rift System (ECRIS) and of other Variscan Massifs in Europe. The low-velocity perturbations beneath the Eger Rift, observed in about 200km-broad zone, agree with shear-velocity models from full-waveform inversion, which also did not identify a mantle plume beneath the ECRIS. Boundaries between mantle domains of three tectonic units that comprise the region, determined from studies of seismic anisotropy, represent weak zones in the otherwise rigid continental mantle lithosphere. In the past, such zones could have channeled upwelling of hot mantle material, which on its way could have modified the mantle domain boundaries and locally thinned the lithosphere.

  4. Small scale heterogeneity of Phanerozoic lower crust: evidence from isotopic and geochemical systematics of mid-Cretaceous granulite gneisses, San Gabriel Mountains, southern California

    USGS Publications Warehouse

    Barth, A.P.; Wooden, J.L.; May, D.J.

    1992-01-01

    An elongate belt of mid-Cretaceous, compositionally banded gneisses and granulites is exposed in Cucamonga terrane, in the southeastern foothills of the San Gabriel Mountains of southern California. Banded gneisses include mafic granulites of two geochemical types: type 1 rocks are similar to high Al arc basalts and andesites but have higher HFSE (high-field-strength-element) abundances and extremely variable LILE (largeion-lithophile-element) abundances, while type 2 rocks are relatively low in Al and similar to alkali rich MOR (midocean-ridge) or intraplate basalts. Intercalated with mafic granulites are paragneisses which include felsic granulites, aluminous gneisses, marble, and calc-silicate gneisses. Type 1 mafic granulites and calcic trondhjemitic pegmatites also oceur as cross-cutting, synmetamorphic dikes or small plutons. Small-scale heterogeneity of deep continental crust is indicated by the lithologic and isotopic diversity of intercalated ortho-and paragneisses exposed in Cucamonga terrane. Geochemical and isotopic data indicate that K, Rb, and U depletion and Sm/Nd fractionation were associated with biotite +/- muscovite dehydration reactions in type 1 mafic granulites and aluminous gneisses during high-grade metamorphism. Field relations and model initial isotopic ratios imply a wide range of protolith ages, ranging from Early Proterozoic to Phanerozoic. ?? 1992 Springer-Verlag.

  5. Palaeomagnetism and geochemistry of Early Palaeozoic rocks of the Barrandian (Teplé-Barrandian Unit, Bohemian Massif): palaeotectonic implications

    NASA Astrophysics Data System (ADS)

    Patočka, F.; Pruner, P.; Štorch, P.

    The Barrandian area (the Teplá-Barrandian unit, Bohemian Massif) provided palaeomagnetic results on Early Palaeozoic rocks and chemical data on siliciclastic sediments of both Middle Cambrian and Early Ordovician to Middle Devonian sedimentary sequences; an outcoming interpretation defined source areas of clastic material and palaeotectonic settings of the siliciclastic rock deposition. The siliciclastic rocks of the earliest Palaeozoic sedimentation cycle, deposited in the Cambrian Přı´bram-Jince Basin of the Barrandian, were derived from an early Cadomian volcanic island arc developed on Neoproterozoic oceanic lithosphere and accreted to a Cadomian active margin of northwestern Gondwana. Inversion of relief terminated the Cambrian sedimentation, and a successory Prague Basin subsided nearby since Tremadocian. Source area of the Ordovician and Early Silurian shallow-marine siliciclastic sediments corresponded to progressively dissected crust of continental arc/active continental margin type of Cadomian age. Since Late Ordovician onwards both synsedimentary within-plate basic volcanics and older sediments had been contributing in recognizable proportions to the siliciclastic rocks. The siliciclastic sedimentation was replaced by deposition of carbonate rocks throughout late Early Silurian to Early Devonian period of withdrawal of the Cadomian clastic material source. Above the carbonates an early Givetian flysch-like siliciclastic suite completed sedimentation in the Barrandian. In times between Middle Cambrian and Early/Middle Devonian boundary interval an extensional tectonic setting prevailed in the Teplá-Barrandian unit. The extensional regime was related to Early Palaeozoic large-scale fragmentation of the Cadomian belt of northwestern Gondwana and origin of Armorican microcontinent assemblage. The Teplá-Barrandian unit was also engaged in a peri-equatorially oriented drift of Armorican microcontinent assemblage throughout the Early Palaeozoic

  6. Late Cretaceous and Cenozoic dynamics of the Bohemian Massif inferred from the paleostress history of the Lusatian Fault Belt

    NASA Astrophysics Data System (ADS)

    Coubal, Miroslav; Málek, Jiří; Adamovič, Jiří; Štěpančíková, Petra

    2015-07-01

    An analysis of fault-slip data from the Lusatian Fault Belt, limiting the Lusatian Block of the Bohemian Massif in the SW, yielded parameters of eight successive paleostress patterns, Late Cretaceous to Plio-Pleistocene in age. These patterns were linked with specific stages in fault kinematics and fault-belt deformation. They include (1) α1, NE- to NNE-directed compression in a reverse fault regime (σ3 vertical) associated with major thrusting and drag zone formation in the latest Cretaceous, preceded by pre-drag origin of deformation bands α0; (2) αβ1-2, WNW-directed extension associated with emplacement of polzenite-group volcanics (≈80-61 Ma) and influx of hydrothermal fluids, overlapping in time with α1; (3) α2, N-directed compression in a reverse fault regime, probably Paleocene in age, associated with thrusting and intensive shear faulting in adjacent parts of blocks; (4) αβ3, Early Oligocene W- to WNW-directed extension in a regime of strike-slip faulting (σ2 vertical), probably connected with an emplacement of phonolitic magmas and influx of hydrothermal fluids; (5) α3, NNW-directed compression associated with activation of transverse/oblique faults of the fault belt, close in age to αβ3 with unclear mutual superposition; (6) β, Late Oligocene-Early Miocene multi-stage N- to NE-directed extension in a normal fault regime, specific to the Bohemian Massif, responsible for downfaulting of the hangingwall block; (7) γ, Mid to Late Miocene NE-directed compression in a reverse fault regime associated with thrusting; (8) δ, Pliocene (to Pleistocene?) NW- to NNW-directed compression in a strike-slip regime, associated with transverse faulting in the fault belt. The identified paleostress patterns show a good correlation with the hitherto identified paleostress fields transmitted to the Alpine foreland and refine the temporal sequence of paleostress states, especially in the post-Lower Miocene period.

  7. Mantle lithosphere transition from the East European Craton to the Variscan Bohemian Massif imaged by shear-wave splitting

    NASA Astrophysics Data System (ADS)

    Vecsey, L.; Plomerová, J.; Babuška, V.

    2014-08-01

    We analyse splitting of teleseismic shear waves recorded during the PASSEQ passive experiment (2006-2008) focused on the upper mantle structure across and around the Trans-European Suture Zone (TESZ). Altogether 1009 pairs of the delay times of the slow split shear waves and orientations of the polarized fast shear waves exhibit lateral variations across the array, as well as back-azimuth dependences of measurements at individual stations. Variable components of the splitting parameters can be associated with fabrics of the mantle lithosphere of tectonic units. In comparison with a distinct regionalization of the splitting parameters in the Phanerozoic part of Europe that particularly in the Bohemian Massif (BM) correlate with the large-scale tectonics, variations of anisotropic parameters around the TESZ and in the East European Craton (EEC) are smooth and of a transitional character. No general and abrupt change in the splitting parameters (anisotropic structure) can be related to the Teisseyre-Tornquist Zone (TTZ), marking the edge of the Precambrian province on the surface. Instead, regional variations of anisotropic structure were found along the TESZ/TTZ. The coherence of anisotropic signals evaluated beneath the northern part of the Brunovistulian in the eastern rim of the BM and the pattern continuation to the NE towards the TTZ, support the idea of a common origin of the lithosphere micro-plates, most probably related to Baltica. Smooth changes in polarizations of the core-mantle boundary refracted shear waves (SKS), polarizations, or even a large number of null splits northward of the BM and further across the TESZ towards the EEC indicate less coherent fabrics and a transitional character of structural changes in the mantle beneath the surface trace of the TESZ/TTZ. The narrow and near-vertical TTZ in the crust does not seem to have a steep continuation in the mantle lithosphere. The mantle part of the TESZ, whose crust was formed by an assemblage of

  8. Single inclusion piezobarometry confirms high-temperature decompression path for Variscan granulites

    NASA Astrophysics Data System (ADS)

    Angel, Ross; Alvaro, Matteo; Mazzucchelli, Mattia; Nimis, Paolo; Nestola, Fabrizio

    2016-04-01

    The identification and chemistry of inclusions trapped in host minerals during growth of the host phase have long been used to infer P-T points on metamorphic paths. The determination of the remnant pressure on the inclusion, e.g., using data from X-ray diffractometry, birefringence analysis or Raman spectroscopy, provides an alternative method of barometry using elasticity theory. A remnant pressure in an inclusion is developed because the inclusion and the host have different thermal expansion and compressibilities, and the inclusion does not expand in response to P and T as would a free crystal. Instead it is restricted to expand only as much as the host mineral, and this constriction in volume can result in inclusions exhibiting over-pressures when the host is studied at room conditions. This concept has been known for a long time, but satisfactory quantitative modelling of inclusion-host systems based on non-linear elasticity theory and precise thermal-pressure euqations of state has only recently come available (Angel et al., 2014, 2015), even though it is still restricted to elastically isotropic minerals. No mineral is elastically isotropic, but garnets and diamond are almost so. Calculations show that diamonds trapped as inclusions in host silicates at P and T within the stability field of diamond should exhibit zero pressure when the samples are recovered to room conditions. However, some diamond inclusions in garnets in granulites are reported to exhibit significant residual overpressures (e.g., Kotková et al., 2011). This indicates that the inclusion was elastically re-equilibrated (e.g., by plastic flow in the garnet host) at high temperatures and lower pressures in the stability field of graphite, consistent also with the observed partial inversion of diamond to graphite. In this case, the elastic analysis of the diamond-in-garnet inclusions provides qualitative independent evidence that the Variscan granulites underwent pressure reduction at high

  9. The Pikwitonei granulite domain: A lower crustal level along the Churchill-Superior boundary in central Manitoba

    NASA Technical Reports Server (NTRS)

    Weber, W.

    1983-01-01

    The greenschist to amphibolite facies tonalite-greenstone terrain of the Gods Lake subprovince grades - in a northwesterly direction - into the granulite facies Pikwitonei domain at the western margins of the Superior Province. The transition is the result of prograde metamorphism and takes place over 50 - 100 km without any structural or lithological breaks. Locally the orthopyroxene isograd is oblique to the structural grain and transects greenstone belts, e.g., the Cross Lake belt. The greenstone belts in the granulite facies and adjacent lower grade domain consist mainly of mafic and (minor) ultramafic metavolcanics, and clastic and chemical metasedimentary rocks. Typical for the greenstone belts crossed by the orthopyroxene isograd are anorthositic gabbros and anorthosites, and plagiophyric mafic flows. The Pikwitonei granulite domain has been interpreted as to represent a lower crustal level which was uplifted to the present level of erosion. On the basis of gravimetric data this uplift has been modelled as an obduction onto the Churchill Province during the Hudsonian orogeny, similar to the Ivrea Zone. The fault between the Churchill and Superior Province is described.

  10. K, Rb, Sr, Ba, U and Th geochemistry of the Lapland Granulites (Fennoscandia). LILE fractionation controlling factors

    NASA Astrophysics Data System (ADS)

    Barbey, P.; Cuney, M.

    1982-12-01

    The LILE geochemical patterns of the three main lithological units (graywacke-shale metasedimentary sequence, tholeiitic metaigneous rocks and migmatitic rocks) of the Lapland Granulite belt are described. K, Ba, Sr and Th concentrations in metasediments are nearly similar to average continental crust, whereas Rb and U are unevenly impoverished. In particular graphitic metashales and calcsilicate rocks are not significantly depleted in uranium. Tholeiitic metaigneous rocks comprises metavolcanics which present K/Rb ratios similar to metasediments, and metaplutonics with LILE abundances close to those of the low-K-tholeiites. Migmatites show wide range in LILE content. Metatexites and diatexites have higher K, Rb, Th and U concentrations and similar K/Rb ratios with respect to equivalent unmobilized rocks. Potassic pegmatoïds are strongly enriched K, Rb, Ba and Th but moderately in Sr and U. Plagioclasic pegmatoids and ferromagnesian restites are rich in Sr and poor in other LIL elements. A comparative review of the LILE geochemistry between Lapland granulites and equivalent lithological units taken from non metamorphosed to high grade terrains suggest that fractionation processes are not systematic but controlled by original lithology and mineralogy, mineral — fluid equilibria during progressive (or retrogressive) metamorphism and mineral-melt-fluid equilibria during anatexis. Moreover, statistical analysis on K-Rb distribution patterns in these various rock types shows that there is no metamorphic trend characteristic of granulite facies terrains as previously suggested.

  11. Deformation mechanisms of pyroxenes in a sheared mafic granulite from the Seiland Igneous Province (northern Norway)

    NASA Astrophysics Data System (ADS)

    degli Alessandrini, Giulia; Menegon, Luca; Malaspina, Nadia; Dijkstra, Arjan; Anderson, Mark

    2015-04-01

    A detailed microstructural and EBSD study was performed on a sheared mafic granulite from the Seiland Igneous Province (northern Norway) to investigate the deformation mechanisms of clino- and orthopyroxenes in a continental lower-crust mafic shear zone. Shearing occurred at T ≈750-820 degC, P ≈0.75-0.95 GPa, following magmatic emplacement and granulite facies riequilibration under dry conditions. The sample consists of clinopyroxene [Ca0.47,Mg0.35,Fe0.18]Si2O3 + orthopyroxene [Ca0.1,Mg0.5,Fe0.4]Si2O3 + plagioclase porphyroclasts (ranging in size from 25 to 650 μm) embedded in a fine-grained matrix (7 μm average grainsize) of cpx + opx + plag and qtz. The cpx and opx porphyroclasts show varying degrees of elongation, with the opx reaching aspect ratios up to 16 and the cpx reaching rare maxima of 7. Elongated opx grains display activity of the {100}<001> and {100}<010> slip systems. Many porphyroclasts have low aspect ratio (≈80% < 3) and show intracrystalline bands of recrystallized grains, as well as micro-boudinage with recrystallized grains in the boudin necks. All porphyroclasts have strong internal misorientations (undulatory and sweeping extinction) and a general lack of recovery features (subgrains). The new grains, with the same composition of the porphyroclasts, shows no host-control. The poly-phase matrix lacks of a crystallographic preferred orientation (CPO). These results suggest that crystal plasticity was not the main deformation mechanism in opx and cpx, and that recovery leading to dynamic recrystallization was not efficient despite the high P-T conditions of deformation. The absence of a CPO in the poly-phase matrix and the well mixed phase distribution are consistent with grains-size-sensitive creep (GSS). We speculate that GSS creep in the matrix has imposed a bulk high strain rate, which hampered crystal plasticity and recovery. High strain rates produced work hardening, causing microcracking and microboudinage in many pyroxene

  12. Long-term studies (1871-2000) on acidification and recovery of lakes in the Bohemian Forest (central Europe).

    PubMed

    Vrba, Jaroslav; Kopácek, Jirí; Fott, Jan; Kohout, Leos; Nedbalová, Linda; Prazáková, Miroslava; Soldán, Tomás; Schaumburg, Jochen

    2003-07-01

    This paper evaluates long-term changes in the atmospheric depositions of S and N compounds, lake water quality, and biodiversity at eight glacial lakes in the Bohemian Forest over the past 130 years. This time interval covers (i) the 'background' pre-acidification status of the lakes, (ii) a period of changes in the communities that can be partly explained by introduction of fish, (iii) a period of strong lake acidification with its adverse impacts on the communities, (iv) the lake reversal from acidity, which includes the recent status of the lakes. The lake water chemistry has followed-with a characteristic hysteresis-both the sharp increase and decline in the deposition trends of strong anions. Remarkable changes in biota have mirrored the changing water quality. Fish became extinct and most species of zooplankton (Crustacea) and benthos (Ephemeroptera and Plecoptera) retreated due to the lake water acidification. Independent of ongoing chemical reversal, microorganisms remain dominant in the recent plankton biomass as well as in controlling the pelagic food webs. The first signs of the forthcoming biological recovery have already been evidenced in some lakes, such as the population of Ceriodaphnia quadrangula (Cladocera) returning into the pelagial of one lake or the increase in both phytoplankton biomass and rotifer numbers in another lake.

  13. Cross-borehole flow analysis to characterize fracture connections in the Melechov Granite, Bohemian-Moravian Highland, Czech Republic

    USGS Publications Warehouse

    Paillet, Frederick L.; Williams, John H.; Urik, Joseph; Lukes, Joseph; Kobr, Miroslav; Mares, Stanislav

    2012-01-01

    Application of the cross-borehole flow method, in which short pumping cycles in one borehole are used to induce time-transient flow in another borehole, demonstrated that a simple hydraulic model can characterize the fracture connections in the bedrock mass between the two boreholes. The analysis determines the properties of fracture connections rather than those of individual fractures intersecting a single borehole; the model contains a limited number of adjustable parameters so that any correlation between measured and simulated flow test data is significant. The test was conducted in two 200-m deep boreholes spaced 21 m apart in the Melechov Granite in the Bohemian-Moravian Highland, Czech Republic. Transient flow was measured at depth stations between the identified transmissive fractures in one of the boreholes during short-term pumping and recovery periods in the other borehole. Simulated flows, based on simple model geometries, closely matched the measured flows. The relative transmissivity and storage of the inferred fracture connections were corroborated by tracer testing. The results demonstrate that it is possible to assess the properties of a fracture flow network despite being restricted to making measurements in boreholes in which a local population of discrete fractures regulates the hydraulic communication with the larger-scale aquifer system.

  14. Field and Microstructure Study of Transpressive Jogdadi shear zone near Ambaji, Aravalli- Delhi Mobile Belt, NW India and its tectonic implication on the exhumation of granulites.

    NASA Astrophysics Data System (ADS)

    Tiwari, Sudheer Kumar; Biswal, Tapas Kumar

    2016-04-01

    Aravalli- Delhi mobile belt is situated in the northwestern part of Indian shield. It comprises tectono- magmatic histories from Archean to Neoproterozoic age. It possesses three tectono- magmatic metamorphic belts namely Bhilwara Supergroup (3000 Ma), Aravalli Supergorup (1800 Ma) and Delhi Supergroup (1100 -750Ma). The Delhi Supergroup is divided in two parts North Delhi and South Delhi; North Delhi (1100 Ma to 850 Ma) is older than South Delhi (850 Ma to 750 Ma). The study area falls in the South Delhi terrane; BKSK granulites are the major unit in this terrane. BKSK granulites comprise gabbro- norite-basic granulite, pelitic granulite, calcareous granulite and occur within the surrounding of low grade rocks as meta- rhyolite, quartzite, mica schist and amphibolites. The high grade and low grade terranes share a sheared margin. Granulites have undergone three phases of folding, intruded by three phases of granites and traversed by many shear zones. One of the shear zones is Jogdadi shear zone which consists of granitic mylonites and other sheared rocks. Jogdadi shear zone carries the evidence of both ductile as well as brittle shearing. It strikes NW- SE; the mylonitic foliation dip moderately to SW or NE and stretching lineations are oblique towards SE. The shear zone is folded and gabbro- norite - basic granulite occurs at the core. One limb of fold passes over coarse grained granite while other limb occurs over gabbro- norite- basic granulite. Presence of mylonitic foliation, asymmetric folding, S-C fabrics, porphyroclasts, mica fishes and book shelf- gliding are indicative of ductile deformation. Most of the porphyroclasts are sigmoidal and delta types but there are also some theta and phi type porphyroclasts. Book shelf-gliding structures are at low angle to the C plane. The shear zone successively shows protomylonite, mylonite and ultramylonites from margin to the centre. As the mylonitization increases recrystallized quartz grains appear. Porphyroclasts

  15. Metamorphism of cordierite gneisses from Eastern Ghat Granulite Terrain, Andhra Pradesh, South India

    NASA Technical Reports Server (NTRS)

    Murthy, D. S. N.; Charan, S. Nirmal

    1988-01-01

    Cordierite-bearing metapelites of the Eastern Ghat granulite terrain occur in close association of Khondalites, quartzites, calc-silicate rocks and charnockites. Rocks occurring between Bobbili in the north and Guntur in the south of Andhra Pradesh are studied. The association of the mineral and textural relationships suggest the following metamorphic reactions: Garnet + sillimanite + quartz = cordierite, hypersthene + sillimanite + quartz = cordierite, sillimanite + spinel = cordierite + corundum, and biotite + quartz + sillimanite = cordierite + K=feldspar. Generally the minerals are not chemically zoned except garnet-biotite showing zoning when they come in close contact with one another. The potential thermometers are provided by the Fe-Mg distribution of coexisting biotite-garnet and cordierite-garnet. Conflicting interpretation of the P/T dependence of these reactions involving cordierite are due to H2O in the cordierite. The presence of alkali feldspar-quartz assemblage which is common in these gneisses will be constrained from melting only if H2O activity is less than 0.5. The piezometric array inferred is convex towards the temperature array, indicating a rapid and isothermal crustal uplift probably aided by thrust tectonics.

  16. Granulite fades Nd-isotopic homogenization in the Lewisian complex of northwest Scotland

    USGS Publications Warehouse

    Whitehouse, M.J.

    1988-01-01

    A published Sm-Nd whole-rock isochron of 2,920 ?? 50 Myr, obtained from a wide range of lithologies in the Lewisian complex of north-west Scotland, was interpreted1 as the time of protolith formation. This date is ???260 Myr older than estimates for the timing of high-grade metamorphism in the complex at ??? 2,660 Myr2'3, and this period is considered to represent the duration of the Lewisian crustal accretion-differentiation superevent (CADS)4. Here we give new Sm-Nd data, obtained specifically from granulite facies tonalitic gneisses, that yield a date of 2,600 ??155 Myr. Although depleted-mantle model ages (tDM suggest >200 Myr of premetamorphic crustal residence, the regression date and its associated initial Nd-isotopic parameters demonstrate Nd-isotopic homogenization during the high-grade event, as well as the probability of general rare-earth-element (REE) mobility. Models for selective element depletion in the complex have previously assumed REE immobility since 2,920 Myr, but the data presented here suggest that a reappraisal of the depletion mechanism is required. ?? 1988 Nature Publishing Group.

  17. Eclogite, peridotite, granulite and associated high-grade rocks from Palu-Koro region, Central Sulawesi, Indonesia: An example for mantle and crust interactions in young orogenic belt

    NASA Astrophysics Data System (ADS)

    Kadarusman, A.; Sopaheluwakan, J.; van Leeuwen, T.

    2002-12-01

    The Neogene collision of three major plates defines the geological development of Eastern Indonesia. Sulawesi is K-shape island lying at the junction of Eurasian, Indo-Australian and Pacific Plates. Eclogites, peridotites, granulites and associated high-grade metamorphic rocks are exposed within the floor and valley of the deep-seated Palu-Koro fault zone in Central Sulawesi. These rocks are occurs as a large number of various size tectonic block juxtaposed with Neogene Palu granitoids. In this particular region, we found evidences that provided another alternative for interaction and upbringing mechanisms of the upper mantle and crustal rocks into the surface. Eclogite are typically grt+omp+qtz+rut assemblages and show well-developed retrograde facies of granulite-grade equilibrium. The mineral assemblages record a cooling history from 1060°C to 750-870°C with decompression from min 20 kbar to 10-12 kbar. The orogenic peridotites consist of spinel- and garnet-bearing lherzolite. The garnet lherzolite P-T time path indicate a prograde subduction zone peridotite, and reach max pressure up to 38 kbar and temperature range between 1025-1210°C. The rim compositions and fine grain minerals give earliest information on the retrograde condition. They generally records decompression of around 4-12 kbar accompanied by cooling of 50-240°C from the peak stage. The granulite-amphibolite facies assemblages are manifest as kelyphitic development in coronas around coarse-grained garnet porphyroblasts, and they have been resulted from the isothermal decompression reaction. The granulites consists of cpx-grt-plag granulite, plag-cpx-opx-grt granulite and feldspar-ky-qtz-grt granulite. The primary paragenesis of mafic granulite shows peak equilibrium of about 700-850°C and 10-16 kbars. Kelyphitic rims around garnet and kyanite are concurrently developed during the fast uplift, similar to other equilibrium microstructure related to mylonitization. High-temperature assemblages of

  18. Variscan potassic dyke magmatism of durbachitic affinity at the southern end of the Bohemian Massif (Lower Austria)

    NASA Astrophysics Data System (ADS)

    Zeitlhofer, Helga; Grasemann, Bernhard; Petrakakis, Konstantin

    2016-06-01

    Dykes in the Strudengau area (SW Moldanubian Zone, Austria) can be mineralogically divided into lamprophyres (spessartites and kersantites) and felsic dykes (granite porphyries, granitic dykes and pegmatoid dykes). Geochemical analyses of 11 lamprophyres and 7 felsic dykes show evidence of fractional crystallization. The lamprophyres are characterized by metaluminous compositions, intermediate SiO2 contents and high amounts of MgO and K2O; these rocks have high Ba (800-3000 ppm) and Sr (250-1000 ppm) contents as well as an enrichment of large-ion lithophile elements over high field strength elements, typical for enriched mantle sources with variable modifications due to fractionation and crustal contamination. This geochemical signature has been reported from durbachites (biotite- and K feldspar-rich mela-syenites particularly characteristic of the Variscan orogen in Central Europe). For most major elements, calculated fractionation trends from crystallization experiments of durbachites give an excellent match with the data from the Strudengau dykes. This suggests that the lamprophyres and felsic dykes were both products of fractional crystallization and subsequent magma mixing of durbachitic and leucogranitic melts. Rb-Sr geochronological data on biotite from five undeformed kersantites and a locally deformed granite porphyry gave cooling ages of c. 334-318 Ma, indicating synchronous intrusion of the dykes with the nearby outcropping Weinsberger granite (part of the South Bohemian Batholith, c. 330-310 Ma). Oriented matrix biotite separated from the locally deformed granite porphyry gave an Rb-Sr age of c. 318 Ma, interpreted as a deformation age during extensional tectonics. We propose a large-scale extensional regime at c. 320 Ma in the Strudengau area, accompanied by plutonism of fractionated magmas of syncollisional mantle-derived sources, mixed with crustal components. This geodynamic setting is comparable to other areas in the Variscan belt documenting an

  19. Petrography, geochemistry and geochronology of granite hosted rhyodacites associated with a disseminated pyrite mineralization (Arnolz, Southern Bohemian Massif, Austria)

    NASA Astrophysics Data System (ADS)

    Göd, Richard; Kurzweil, Johannes; Klötzli, Urs

    2016-09-01

    The study focuses on a subvolcanic rhyodacite dyke intruding a fine grained biotite granite and paragneisses of the South Bohemian Massif, part of the Variscan Orogenic Belt in Central Europe. The subvertical dyke strikes NNE, displays a thickness of about 30 m and has been traced by boulder mapping for approximately 7 km. The rhyodacites have been affected by two hydrothermal fluids. An older one of oxidizing condition giving rise to a reddish to brownish type of rock (Type I) and a younger fluid of reducing condition causing a greenish variety (Type II). The hydrothermal alteration is associated with the formation of the clay minerals chlorite, sericite, kaolinite and smectite and a disseminated pyrite mineralization. Bulk chemistries of the rhyodacites emphasize the hydrothermal alterations to be isochemical with the exception of sulphur enriched up to a maximum of 0.6 wt%. Trace element composition of the rhyodacites points to a barren geochemical environment in terms of base and precious elements. Sulphur isotope investigations of pyrites from the rhyodacites and the hosting granites respectively yield d34S data ranging from +0.07 to -2.22 ‰, emphasizing a magmatic origin of the sulphur. Geochronological investigations yield in situ U/Pb zircon ages of 312 ± 4 Ma for the biotite granite and of 292 ± 4 Ma for the rhyodacitic dykes indicating a time gap of ≈ 20 Ma between these two intrusive events. A contemporaneous but geochemically specialized granitic intrusion associated with NW striking "felsitic" dykes occurs about 10 to 20 km to the NW of Arnolz. However, the rhyodacites around Arnolz differ significantly from these felsitic dykes in their geochemistry and alteration phenomena which points to a different magmatic source. This coincides with a change in the orientation of the dykes from a NW direction controlling the geochemically specialized intrusions in the NW to a dominating NNE direction mirrored by the studied rhyodacites at Arnolz.

  20. Country, cover or protection: what shapes the distribution of red deer and roe deer in the Bohemian Forest Ecosystem?

    PubMed

    Heurich, Marco; Brand, Tom T G; Kaandorp, Manon Y; Šustr, Pavel; Müller, Jörg; Reineking, Björn

    2015-01-01

    The Bohemian Forest Ecosystem encompasses various wildlife management systems. Two large, contiguous national parks (one in Germany and one in the Czech Republic) form the centre of the area, are surrounded by private hunting grounds, and hunting regulations in each country differ. Here we aimed at unravelling the influence of management-related and environmental factors on the distribution of red deer (Cervus elaphus) and roe deer (Capreolus capreolus) in this ecosystem. We used the standing crop method based on counts of pellet groups, with point counts every 100 m along 218 randomly distributed transects. Our analysis, which accounted for overdispersion as well as zero inflation and spatial autocorrelation, corroborated the view that both human management and the physical and biological environment drive ungulate distribution in mountainous areas in Central Europe. In contrast to our expectations, protection by national parks was the least important variable for red deer and the third important out of four variables for roe deer; protection negatively influenced roe deer distribution in both parks and positively influenced red deer distribution in Germany. Country was the most influential variable for both red and roe deer, with higher counts of pellet groups in the Czech Republic than in Germany. Elevation, which indicates increasing environmental harshness, was the second most important variable for both species. Forest cover was the least important variable for roe deer and the third important variable for red deer; the relationship for roe deer was positive and linear, and optimal forest cover for red deer was about 70% within a 500 m radius. Our results have direct implications for the future conservation management of deer in protected areas in Central Europe and show in particular that large non-intervention zones may not cause agglomerations of deer that could lead to conflicts along the border of protected, mountainous areas.

  1. Country, Cover or Protection: What Shapes the Distribution of Red Deer and Roe Deer in the Bohemian Forest Ecosystem?

    PubMed Central

    Heurich, Marco; Brand, Tom T. G.; Kaandorp, Manon Y.; Šustr, Pavel; Müller, Jörg; Reineking, Björn

    2015-01-01

    The Bohemian Forest Ecosystem encompasses various wildlife management systems. Two large, contiguous national parks (one in Germany and one in the Czech Republic) form the centre of the area, are surrounded by private hunting grounds, and hunting regulations in each country differ. Here we aimed at unravelling the influence of management-related and environmental factors on the distribution of red deer (Cervus elaphus) and roe deer (Capreolus capreolus) in this ecosystem. We used the standing crop method based on counts of pellet groups, with point counts every 100 m along 218 randomly distributed transects. Our analysis, which accounted for overdispersion as well as zero inflation and spatial autocorrelation, corroborated the view that both human management and the physical and biological environment drive ungulate distribution in mountainous areas in Central Europe. In contrast to our expectations, protection by national parks was the least important variable for red deer and the third important out of four variables for roe deer; protection negatively influenced roe deer distribution in both parks and positively influenced red deer distribution in Germany. Country was the most influential variable for both red and roe deer, with higher counts of pellet groups in the Czech Republic than in Germany. Elevation, which indicates increasing environmental harshness, was the second most important variable for both species. Forest cover was the least important variable for roe deer and the third important variable for red deer; the relationship for roe deer was positive and linear, and optimal forest cover for red deer was about 70% within a 500 m radius. Our results have direct implications for the future conservation management of deer in protected areas in Central Europe and show in particular that large non-intervention zones may not cause agglomerations of deer that could lead to conflicts along the border of protected, mountainous areas. PMID:25781942

  2. Monazite and zircon as major carriers of Th, U, and Y in peraluminous granites: examples from the Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Breiter, Karel

    2016-06-01

    The chemical compositions of zircon and monazite and the relationships between the contents of Th, U, Y, and REE in both minerals and in the bulk samples of their parental rocks were studied in three Variscan composite peraluminous granite plutons in the Bohemian Massif. It was established that granites of similar bulk composition contain zircon and monazite of significantly different chemistry. Monazite typically contains 5-13 wt% (rarely up to 28 wt%) ThO2, 0.4-2 wt% (up to 8.2 wt%) UO2, and 0.5-2 wt% (up to 5 wt%) Y2O3, whereas zircon typically contains less than 0.1 wt% (rarely up to 1.7 wt%) ThO2, less than 1 wt% UO2 (in the Plechý/Plockenstein granite, commonly, 1-2 wt% and scarcely up to 4.8 wt% UO2), and less than 1 wt% Y2O3 (in the Nejdek pluton often 2-5, maximally 7 wt% Y2O3). Monazite is an essential carrier of thorium, hosting more than 80 % of Th in all studied granites. Monazite also appears to be an important carrier of Y (typically 14-16 %, and in the Melechov pluton, up to 81 % of the total rock content) and U (typically 18-35 % and occasionally 6-60 % of the total rock budget). The importance of zircon for the rock budget of all the investigated elements in granites is lower: 4-26 % U, 5-17 % Y, and less than 5 % Th.

  3. Silvibacterium bohemicum gen. nov. sp. nov., an acidobacterium isolated from coniferous soil in the Bohemian Forest National Park.

    PubMed

    Lladó, Salvador; Benada, Oldrich; Cajthaml, Tomáš; Baldrian, Petr; García-Fraile, Paula

    2016-02-01

    During the course of a study assessing the bacterial diversity of a coniferous forest soil (pH 3.8) in the Bohemian Forest National Park (Czech Republic), we isolated strain S15(T) which corresponded to one of the most abundant soil OTUs. Strain S15(T) is represented by Gram-negative, motile, rod-like cells that are 0.3-0.5μm in diameter and 0.9-1.1μm in length. Its pH range for growth was 3-6, with optimal conditions found at approximately 4-5. It can grow at temperatures between 20°C and 28°C, with optimum growth at 22-24°C. Its respiratory quinone is MK-8, and its main fatty acid is iso-C15:0 (73.7%). The G+C DNA content was 58.2mol%. According to the 16S rRNA gene sequence analysis, strain S15(T) belongs to subdivision 1 of the phylum Acidobacteria, being affiliated to the cluster of Acidipila rosea AP8(T) and Acidobacterium capsulatum ATCC 51196(T). Analysis of the S15(T) genome revealed the presence of 404 genes that are involved in carbohydrate metabolism, which indicates the metabolic potential to degrade polysaccharides of plant and fungal origin. Based on genotypic and phenotypic characteristics, the strain S15(T) represents a new genus and species within the family Acidobacteriaceae, for which the name Silvibacterium bohemicum gen. nov., sp. nov. is proposed (type strain S15(T)=LMG 28607(T)=CECT 8790(T)).

  4. Pseudotachylytes of the Deep Crust: Examples from a Granulite-Facies Shear Zone

    NASA Astrophysics Data System (ADS)

    Orlandini, O.; Mahan, K. H.; Regan, S.; Williams, M. L.; Leite, A.

    2013-12-01

    The Athabasca Granulite Terrane is an exhumed section of deep continental crust exposed in the western Canadian shield. The terrane hosts the 1.88 Ga Cora Lake shear zone, a 3-5 km wide sinistral and extensional oblique-slip system that was active at high-pressure granulite-grade conditions ( ~1.0 GPa, >800°C to ~0.8 GPa and 700 °C). Pseudotachylyte, a glassy vein-filling substance that results from frictional melting during seismic slip, is common in ultramylonitic strands of the shear zone, where veins run for tens of meters subparallel to foliation. Some but not all PST veins have been overprinted with the Cora Lake shear zone foliation, and undeformed PST locally bears microlitic garnet. The frictional melts that quench into PST may reach >1400 °C, but are extremely localized and cool to country rock temperatures within minutes, resulting in glass and/or microlitic mineral growths. The melt itself is thought by many to be in disequilibrium with the host rock due to its rapid nature, but during cooling equilibrium is probably reached at small scales. This allows for microprobe analysis of adjacent microlites for thermobarometric calculations. Preliminary results from undeformed (e.g., youngest of multiple generations) PST suggest that quenching occurred in upper amphibolite facies ambient conditions and is compatible with later stages of Cora Lake shear zone activity. Host-rock mylonites contain abundant garnet and pyroxene sigma clasts indicating sinistral shear, and where PST-bearing slip surfaces are found at low angles to the foliation, they display sinistral offset. The host rock contains abundant macroscopic and microscopic sinistral shear fracture systems (e.g., Riedel [R], Y, and P displacement surfaces) within the immediate proximity of PST veins, indicating a complex interplay of brittle and ductile behavior that is interpreted to be genetically related to the formation of the PST. The shear fracture systems are characterized by sharply bounded

  5. Wagnerite-MA5BC From Granulite-Facies Paragneiss, Larsemann Hills, Prydz Bay, East Antarctica

    NASA Astrophysics Data System (ADS)

    Ren, L.; Grew, E. S.; Xiong, M.; Ma, Z.

    2003-04-01

    Wagnerite-Ma5bc, which is one of three new polytypes of (Mg,Fe)_2(PO_4)(F,OH) (Chopin, Armbruster &Leyx, this conference), occurs in paragneiss associated with banded cordierite-prismatine gneiss. It forms anhedral to euhedral grains mostly 0.5-2 mm across, some with a tabular habit. Textures are consistent with a primary assemblage wagnerite-Ma5bc + plagioclase + apatite + magnetite + ilmenite-hematite that crystallized under granulite-facies conditions (750 - ˜860^oC, 6-7 kbar). Also present are biotite, quartz, K-feldspar, monazite, xenotime, corundum, hercynite, sulfide. Electron microprobe analyses give P_2O_5 41.39, SiO_2 0.06, TiO_2 0.88, FeO 4.16, MnO 0.09, MgO 44.54, CaO 0.09, F 6.87, H_2O (calculated for OH + F = 1) 2.04, O=F -2.89, total 97.22 wt%, corresponding to (Mg1.88Fe0.10Ti0.02)(P0.99O_4)(F0.61OH0.39). Space group is Ia. Lattice parameters a = 9.645(2)Å, b = 31.659(6) Å , c = 11.914(2) Å, â=108.26 (3)^o, V= 3455(1) Å^3 for Z=40, Dcalc = 3.18(1) g/cm^3. The crystal structure has been solved by direct methods and refined to R_1=0.0413 for the independent 4521 reflections [I>2σ(I)] using MoKα radiation. The primary difference among the wagnerite polytypes is ordering of the (F,OH) positions. F can occupy one of two positions resulting in two distinct configurations along the a direction. In magniotriplite the sequence of configurations in the b direction is disordered, whereas in wagnerite-Ma2bc the sequence is ordered 121212... and in wagnerite-Ma5bc, 12112... Magniotriplite and the wagnerite polytypes do not overlap in composition: minerals richer in Fe and Mn (average ionic radius >= 0.76 Å) crystallize as the disordered minerals in the triplite group, whereas highly magnesian minerals (average ionic radius <= 0.73 Å or >= 86% of the Mg end member) crystallize as the ordered wagnerite polytypes. Magniotriplite formed at moderate temperatures (e.g., amphibolite-facies), whereas wagnerite-Ma2bc is found in rocks formed under a wide range

  6. Texture and anisotropy analysis of a laminated lower crust: a neutron diffraction study of felsic granulites

    NASA Astrophysics Data System (ADS)

    Benitez Perez, J.; Gomez Barreiro, J.; Martinez-Catalan, J. R.; Castiñeiras Garcia, P.; Vogel, S. C.; Wenk, H.; Alvarez Valero, A.

    2013-12-01

    Quantitative fabric analyses of high-P and high-T tectonites were done with HIPPO, a Time-Of-Flight (TOF) neutron diffractometer at Los Alamos National Lab. Samples were collected in the Sobrado unit (NW Spain), a tectonic stack of highly deformed slices of metabasites, paragneisses and ultramafic rocks. Metamorphism ranges from granulites on top, to eclogites at the bottom of the unit. The ensemble represents and excellent example of laminated lower crust. The alternation of mechanically contrasted lithologies and/or the development of crystal preferred orientation might result into anisotropy. We explore the contribution of crystallographic preferred orientation or texture to the seismic anisotropy of the lower crust. Since strain partitioning occurred between mechanically strong and weak lithologies, a higher crystal preferred orientation is expected along the weak levels: the metasediments. TOF neutron diffraction experiments were conducted in HIPPO (LANSCE) with high-P and high-T mylonitic felsic paragneisses. Quantitative texture analysis of neutron data was accomplished by using the Rietveld method, with E-WIMW algorithm, implemented in the program package MAUD (Material Analysis Using Diffraction; Lutterotti, 1999). The orientation distribution function (ODF) for each mineral was calculated in MAUD and then processed in BEARTEX (Wenk et al. 1998). Selected pole figures were plotted for major components, quartz, plagioclase and biotite (first setting in monoclinic crystals). Texture patterns are compatible with non-coaxial progressive deformation and discussed accordingly in terms of dislocation activity. Besides, seismic waves velocities were computed from the texture data in BEARTEX. Calculated velocities and anisotropy were based on ODF, volume fraction of each mineral and their single-crystal elastic constant. Kinematic and mechanical implications are discussed in terms of the regional geology. The correlation of texture, mineral composition and seismic

  7. U-Pb age of the Diana Complex and Adirondack granulite petrogenesis

    USGS Publications Warehouse

    Basu, A.R.; Premo, W.R.

    2001-01-01

    U-Pb isotopic analyses of eight single and multi-grain zircon fractions separated from a syenite of the Diana Complex of the Adirondack Mountains do not define a single linear array, but a scatter along a chord that intersects the Concordia curve at 1145 ?? 29 and 285 ?? 204 Ma. For the most concordant analyses, the 207Pb/206Pb ages range between 1115 and 1150 Ma. Detailed petrographic studies revealed that most grains contained at least two phases of zircon growth, either primary magmatic cores enclosed by variable thickness of metamorphic overgrowths or magmatic portions enclosing presumably older xenocrystic zircon cores. The magmatic portions are characterized by typical dipyramidal prismatic zoning and numerous black inclusions that make them quite distinct from adjacent overgrowths or cores when observed in polarizing light microscopy and in back-scattered electron micrographs. Careful handpicking and analysis of the "best" magmatic grains, devoid of visible overgrowth of core material, produced two nearly concordant points that along with two of the multi-grain analyses yielded an upper-intercept age of 1118 ?? 2.8 Ma and a lower-intercept age of 251 ?? 13 Ma. The older age is interpreted as the crystallization age of the syenite and the younger one is consistent with late stage uplift of the Appalachian region. The 1118 Ma age for the Diana Complex, some 35 Ma younger than previously believed, is now approximately synchronous with the main Adirondack anorthosite intrusion, implying a cogenetic relationship among the various meta-igneous rocks of the Adirondacks. The retention of a high-temperature contact metamorphic aureole around Diana convincingly places the timing of Adirondack regional metamorphism as early as 1118 Ma. This result also implies that the sources of anomalous high-temperature during granulite metamorphism are the syn-metamorphic intrusions, such as the Diana Complex.

  8. Ultra-high temperature granulite-facies metamorphic rocks from the Mozambique belt of SW Tanzania

    NASA Astrophysics Data System (ADS)

    Sommer, H.; Kröner, A.

    2013-06-01

    The metamorphic rocks in the Neoproterozoic (Pan-African) Mozambique belt of southwestern Tanzania, around the town of Songea, can be subdivided into one- and two pyroxene bearing charnockitic gneisses, migmatitic granitoid gneisses and amphibolite-facies metapelites. Lower-grade amphibolite-facies rocks are rare and can be classified as sillimanite- and/or garnet-bearing metapelites. Most of the studied charnockitic gneisses show excellent corona textures with large orthopyroxene grains rimmed by clinopyroxene, followed by quartz and well developed garnet rims due to the reaction Opx + Pl = Grt + Cpx + Qtz that formed during isobaric cooling. These and other charnockitic gneisses show symplectites of orthopyroxene and An-rich plagioclase that resulted from the breakdown of garnet during isothermal decompression due to the reaction Grt + Cpx + Qtz = Opx + Pl. Geothermobarometric calculations yield up to ~ 1050 °C and up to ~ 12 kbar for peak metamorphic conditions. These are higher temperature and slightly lower pressure conditions than reported for other granulite-facies terrains in the Mozambique belt of Tanzania. Single zircon Pb-Pb evaporation and U-Pb SHRIMP ages for magmatic zircons extracted from two charnockitic and two granitic gneisses cluster in two groups, one at ~ 750 Ma and one at ~ 1150 Ma with the older reflecting the time of emplacement of the igneous precursors, and the younger approximating the time of charnockitization. These protolith ages are similar to those farther east in the Masasi area of southern Tanzania, as well as in northern Mozambique and in southern Malawi, and suggest that the Mozambique belt consists of chronologically heterogeneous assemblages whose pre-metamorphic tectonic setting remains obscure.

  9. Fluid induced microstructures in granulites from the Reynolds Range, central Australia

    NASA Astrophysics Data System (ADS)

    Prent, Alexander; Beinlich, Andreas; Raimondo, Tom; Putnis, Andrew

    2016-04-01

    Fluids play a major role in the evolution of the Earth's crust, driving metamorphic reactions, facilitating transport of mass and heat, and changing the physical properties of rock. Shear zones present in intraplate orogens are ideal natural laboratories to study the relationship of fluid-driven rock weakening to deformation, and thus the impact of fluid availability on the tectonic reworking of continental interiors. Here we present preliminary observations from the Aileron Shear Zone (ASZ), Reynolds Range, central Australia, a major crustal-scale thrust of the Palaeozoic Alice Springs Orogen (ASO). This study focuses on the effects of fluids on the mineralogy and mineral chemistry of deep crustal rocks collected from a transect running through the ASZ. The ASZ is thought to have been of major importance during exhumation of the ASO, and exhumes a partly retrogressed suite of felsic and metasedimentary granulite facies gneisses. Hydration reactions associated with retrogression resulted in the partial replacement of orthopyroxene and numerous myrmekite textures associated with plagioclase and mica. In undeformed samples, orthopyroxene (En56 Fer44) rims are partly replaced by a zoned sequence of biotite (Phl70 Ann30), sub-parallel rims of magnetite, biotite and K-feldspar (Or87). Deformed samples gradually show an increase in dynamic recrystallization of quartz, with fully recrystallized bands of foam texture quartz defining the foliation together with biotite. Quartz and minor biotite replacement then dominates the mineral assemblage with increasing strain. The presence of fluid-driven mineral replacement reactions in undeformed samples suggests that hydration predates shearing and exhumation, and furthermore, that strain may have been localised in areas of intense hydration and rock weakening. Retrograde reactions and myrmekite textures suggest the availability of a silica-saturated fluid. Additional mass-balance calculations will be applied to constrain the

  10. Peraluminous sapphirine-cordierite pods in Mg-rich orthopyroxene granulite from southern India: Implications for lower crustal processes

    NASA Astrophysics Data System (ADS)

    Shazia, J. R.; Santosh, M.; Sajeev, K.

    2012-09-01

    Sapphirine-cordierite intergrowths occur as pods within garnet-absent, high-Mg orthopyroxene-granulite xenoliths in the Kambam valley, Madurai Block, southern India. Whereas the cores of the pods are composed of sapphirine (XMg = 0.871-0.897) - cordierite (XMg = 0.892-0.931) intergrowth along with rutile, zircon and monazite, the rims are characterized by cordierite, apatite, plagioclase, K-feldspar, quartz and minor calcite. The surrounding matrix comprises orthopyroxene (maximum Al2O3 4.1 wt.%, XMg 0.848-0.850), plagioclase, biotite and quartz, similar to the assemblage in the surrounding charnockites. Sapphirine in the Kambam rocks is characterized by high Al contents with an end-member composition in the range of 7:9:3 and 3:5:1. The occurrence of peraluminous sapphirine in association with cordierite and in the absence of phases such as sillimanite and garnet is distinct from ultrahigh-temperature assemblages in other localities within the Madurai Block. The peraluminous composition of the pods suggests that these domains could represent cryptic pathways through which aluminous melts migrated. The reaction of such peraluminous melts with Mg-rich orthopyroxene in the host granulite at temperatures of 1025 °C and pressures around 8 kbar as computed from phase equilibria modeling followed by an isobaric cooling is inferred to have generated the sapphirine-cordierite pods. The unusual high-Mg orthopyroxene granulite suggests interaction of supracrustal rocks with mafic magmas, which probably acted as the heat source for the partial melting of lower crust and UHT metamorphism.

  11. Partial melting of apatite-bearing charnockite, granulite, and diorite: Melt compositions, restite mineralogy, and petrologic implications

    NASA Technical Reports Server (NTRS)

    Beard, James S.; Lofgren, Gary E.; Sinha, A. Krishna; Tollo, Richard P.

    1994-01-01

    Melting experiments (P = 6.9 kbar, T = 850-950 deg C, NNO is less than fO2 is less than HM) were done on mafic to felsic charnockites, a dioritic gneiss, and a felsic garnet granulite, all common rock types in the Grenville basement of eastern North America. A graphite-bearing granulite gneiss did not melt. Water (H2O(+) = 0.60 to 2.0 wt %) is bound in low-grade, retrograde metamorphic minerals and is consumed during the earliest stages of melting. Most melts are water-undersaturated. Melt compositions range from metaluminous, silicic granodiorite (diorite starting composition) to peraluminous or weakly metaluminous granites (all others). In general, liquids become more feldspathic, less silicic, and less peraluminous and are enriched in FeO, MgO, and TiO2 with increasing temperature. Residual feldspar mineralogy controls the CaO, K2O, and Na2O contents of the partial melts and the behavior of these elements can be used, particularly if the degree of source melting can be ascertained, to infer some aspects of the feldspar mineralogy of the source. K-feldspar, a common restite phase in the charnockite and granulite (but not the diorite) should control the behavior of Ba and, possibly, Eu in these systems and yield signatures of these elements that can distinguish source regions and, in some cases, bulk versus melt assimilation. Apatite, a common restite phase, is enriched in rare earth elements (REE), especially middle REE. Retention of apatite in the restite will result in steep, light REE-enriched patterns for melts derived from the diorite and charnockites.

  12. Regional variation in the Amitsoq gneisses related to crustal levels during late Archean granulite facies metamorphism: Southern west Greenland

    NASA Technical Reports Server (NTRS)

    Nutman, A. P.; Bridgwater, D.; Mcgregor, V. R.

    1986-01-01

    The dominant lithology at Kangimut sangmissoq is described as nebulitic tonalitic gneiss containing highly distended plagioclase phyric amphibolites. The gneiss amphibolite complex was intruded by Nuk gneiss between 3.05 and 2.90 Ga and later (2.6 to 2.7 Ga) by post granulite facies granitoid sheets. The amphibolites are though to be Ameralik dikes and the older gray gneiss are then Amitsoq by definition. The problem arises when the isotopic data are considered, none of which indicate rocks older that about 3.0 Ga.

  13. Constraints on formation and evolution of the lunar crust from feldspathic granulitic breccias NWA 3163 and 4881

    NASA Astrophysics Data System (ADS)

    McLeod, Claire L.; Brandon, Alan D.; Fernandes, Vera A.; Peslier, Anne H.; Fritz, Jörg; Lapen, Thomas; Shafer, John T.; Butcher, Alan R.; Irving, Anthony J.

    2016-08-01

    Lunar granulitic meteorites provide new constraints on the composition and evolution of the lunar crust as they are potentially derived from outside the Apollo and Luna landing sites. Northwest Africa (NWA) 3163, the focus of this study, and its paired stones NWA 4881 and NWA 4483, are shocked granulitic noritic anorthosites. They are petrographically and compositionally distinct from the Apollo granulites and noritic anorthosites. Northwest Africa 3163 is REE-depleted by an order of magnitude compared to Apollo granulites and is one of the most trace element depleted lunar samples studied to date. New in-situ mineral compositional data and Rb-Sr, Ar-Ar isotopic systematics are used to evaluate the petrogenetic history of NWA 3163 (and its paired stones) within the context of early lunar evolution and the bulk composition of the lunar highlands crust. The NWA 3163 protolith was the likely product of reworked lunar crust with a previous history of heavy REE depletion. The bulk feldspathic and pyroxene-rich fragments have 87Sr/86Sr that are indistinguishable and average 0.699282 ± 0.000007 (2σ). A calculated source model Sr TRD age of 4.340 ± 0.057 Ga is consistent with (1) the recently determined young FAS (Ferroan Anorthosite) age of 4.360 ± 0.003 Ga for FAS 60025, (2) 142Nd model ages for the closure of the Sm-Nd system for the mantle source reservoirs of the Apollo mare basalts (4.355-4.314 Ga) and (3) a prominent age peak in the Apollo lunar zircon record (c. 4.345 Ga). These ages are ∼100 Myr younger than predicted timescales for complete LMO crystallization (∼10 Myrs after Moon formation, Elkins-Tanton et al., 2011). This supports a later, major event during lunar evolution associated with crustal reworking due to magma ocean cumulate overturn, serial magmatism, or a large impact event leading to localized or global crustal melting and/or exhumation. The Ar-Ar isotopic systematics on aliquots of paired stone NWA 4881 are consistent with an impact event

  14. Magnetic Anomalies and Rock Magnetic Properties Related to Deep Crustal Rocks of the Athabasca Granulite Terrane, Northern Canada

    NASA Astrophysics Data System (ADS)

    Brown, L. L.; Williams, M. L.

    2010-12-01

    The Athabasca granulite terrane in northernmost Saskatchewan, Canada is an exceptional exposure of lower crustal rocks having experienced several high temperature events (ca 800C) during a prolonged period of deep-crustal residence (ca 1.0 GPa) followed by uplift and exhumation. With little alteration since 1.8 Ga these rocks allow us to study ancient lower crustal lithologies. Aeromagnetic anomalies over this region are distinct and complex, and along with other geophysical measurements, define the Snowbird Tectonic zone, stretching NE-SW across northwestern Canada, separating the Churchill province into the Hearne (mid-crustal rocks, amphibolite facies) from the Rae (lower crust rocks, granulite facies). Distinct magnetic highs and lows appear to relate roughly to specific rock units, and are cut by mapped shear zones. Over fifty samples from this region, collected from the major rock types, mafic granulites, felsic granulites, granites, and dike swarms, as well as from regions of both high and low magnetic anomalies, are being used to investigate magnetic properties. The intention is to investigate what is magnetic in the lower crust and how it produces the anomalies observed from satellite measurements. The samples studied reveal a wide range of magnetic properties with natural remanent magnetization ranging from an isolated high of 38 A/m to lows of 1 mA/m. Susceptibilities also range over several orders of magnitude, from 1 to 1 x10-4 SI. Magnetite is identified in nearly all samples using both low and high temperature measurements, but concentrations are generally very low. Hysteresis properties on 41 samples reveal nearly equal numbers of samples represented by PSD and MD grains, with a few samples (N=6) plotting in or close to the SD region. Low temperature measurements indicate that most samples contain magnetite, showing a marked Verway transition around 120K. Also identified in nearly half of the samples is pyrrhotite, noted by low temperature

  15. Fluid inclusions in Scourian granulites from the Lewisian complex of NW Scotland: evidence for CO 2-rich fluid in Late Archaean high-grade metamorphism

    NASA Astrophysics Data System (ADS)

    Andersen, T.; Whitehouse, M. J.; Burke, E. A. J.

    1997-07-01

    In this paper the first fluid-inclusion data are presented from Late Archaean Scourian granulites of the Lewisian complex of mainland northwest Scotland. Pure CO 2 or CO 2-dominated fluid inclusions are moderately abundant in pristine granulites. These inclusions show homogenization temperatures ranging from - 54 to + 10 °C with a very prominent histogram peak at - 16 to - 32 °C. Isochores corresponding to this main histogram peak agree with P-T estimates for granulite-facies recrystallization during the Badcallian (750-800 °C, 7-8 kbar) as well as with Inverian P-T conditions (550-600 °C, 5 kbar). The maximum densities encountered could correspond to fluids trapped during an early, higher P-T phase of the Badcallian metamorphism (900-1000 °C, 11-12 kbar). Homogenization temperatures substantially higher than the main histogram peak may represent Laxfordian reworking (≤ 500 °C, < 4 kbar). In the pristine granulites, aqueous fluid inclusions are of very subordinate importance and occur only along late secondary healed fractures. In rocks which have been retrograded to amphibolite facies from Inverian and/or Laxfordian shear zones, CO 2 inclusions are conspicuously absent; only secondary aqueous inclusions are present, presumably related to post-granulite hydration processes. These data illustrate the importance of CO 2-rich fluids for the petrogenesis of Late Archaean granulites, and demonstrate that early fluid inclusions may survive subsequent metamorphic processes as long as no new fluid is introduced into the system.

  16. The Blaník Gneiss in the southern Bohemian Massif (Czech Republic): a rare rock composition among the early palaeozoic granites of Variscan Central Europe

    NASA Astrophysics Data System (ADS)

    René, Miloš; Finger, Fritz

    2016-08-01

    Metamorphosed and deformed tourmaline-bearing leucogranites with a Cambro-Ordovician formation age are widespread in the Monotonous Group of the Variscan southern Bohemian Massif, Czech Republic. The rocks, known locally as Blaník gneiss, are strongly peraluminous and classify as phosphorus-rich low-T, S-type granite. The magma formed from a metapelitic source, most likely through muscovite dehydration melting. With respect to its low-T origin and the abundance of tourmaline, the Blaník gneiss is exotic within the spectrum of Early Palaeozoic granites of the Variscan fold belt of Central Europe. Coeval granitic gneisses in the neighbouring Gföhl unit of the Bohemian Massif can be classified as higher T S-type granites and were probably generated through biotite dehydration melting. The geochemical differences between the Early Palaeozoic granitic magmatism in the Gföhl unit and the Monotonous Group support models claiming that these two geological units belonged to independent peri-Gondwana terranes before the Variscan collision. It is suggested here, that the Gföhl unit and the Monotonous Group represent zones of higher and lower heat flow within the Early Palaeozoic northern Gondwana margin, respectively. The geochemical data presented in this study could be helpful for terrane correlations and palaeogeographic reconstructions.

  17. Granulite-amphibolite facies metasediments from the Serre (Calabria, Southern Italy): their protoliths and the processes controlling their chemistry

    NASA Astrophysics Data System (ADS)

    Maccarrone, Eleonora; Paglionico, Antonio; Piccarreta, Giuseppe; Rottura, Allesandro

    1983-04-01

    In the northwestern Serre, a near continuous section through the Palaeozoic lower continental crust crops out. This paper deals with granulite facies metasedimentary rocks of this section. Fifty-five chemical analyses (major elements, Sc, V, Cr, Co, Ni, Rb, Sr, Y, Nb and Ba) are given. Chemical data indicate that the original sedimentary sequence was made up of arenites in the lower part and mainly Fe and Mg rich pelites in the upper part. The metapelites experienced anatexis and removal of some melt, whereas the meta-arenites suffered only incipient anatexis and became dehydration granulites. The various rock types display an overall relatively low K/Rb ratio due mainly to the stability of K- and Rb-retaining phases. A weighted mean composition of the fragment of the lower continental crust outcropping in the Serre has been established by integrating the chemical data for metasediments (55 analyses), metabasites (92 analyses) and dioritic and tonalitic gneisses (10 analyses) with the field data. This composition compared to the compositions of the bulk continental crust and of other sections considered as belonging to the lower crust, confirms the hypothesis that (1) the lower crust is heterogeneous, and (2) it is more basic than the continental crust.

  18. Multiple migmatite events and cooling from granulite facies metamorphism within the Famatina arc margin of northwest Argentina

    NASA Astrophysics Data System (ADS)

    Mulcahy, Sean R.; Roeske, Sarah M.; McClelland, William C.; Ellis, Joshua R.; Jourdan, Fred; Renne, Paul R.; Vervoort, Jeffrey D.; Vujovich, Graciela I.

    2014-01-01

    The Famatina margin records an orogenic cycle of convergence, metamorphism, magmatism, and extension related to the accretion of the allochthonous Precordillera terrane. New structural, petrologic, and geochronologic data from the Loma de Las Chacras region demonstrate two distinct episodes of lower crustal migmatization. The first event preserves a counterclockwise pressure-temperature path in kyanite-K-feldspar pelitic migmatites that resulted in lower crustal migmatization via muscovite dehydration melting at ˜12 kbar and 868°C at 461 ±1.7 Ma. The shape of the pressure temperature path and timing of metamorphism are similar to those of regional midcrustal granulites and suggest pervasive Ordovician migmatization throughout the Famatina margin. One-dimensional thermal modeling coupled with regional isotopic data suggests Ordovician melts remained at temperatures above their solidus for 20-30 Ma following peak granulite facies metamorphism, throughout a time period marked by regional oblique convergence. The onset of synconvergent extension occurred only after regional migmatites cooled beneath their solidus and was synchronous with the cessation of Precordillera terrane accretion at ˜436 Ma. The second migmatite event was regionally localized and occurred at ˜700°C and 12 kbar between 411 and 407 Ma via vapor saturated melting of muscovite. Migmatization was synchronous with extension, exhumation, and strike-slip deformation that likely resulted from a change in the plate boundary configuration related to the convergence and collision of the Chilenia terrane.

  19. Brittle-viscous transition in granulite-facies perthites: implications for lower crustal strength

    NASA Astrophysics Data System (ADS)

    Menegon, L.; Stünitz, H.; Nasipuri, P.; Heilbronner, R.; Svahnberg, H.

    2012-04-01

    Deformation in granulite facies rocks of the mangerite-charnockites in Lofoten (Norway) is localized in shear zones, which have formed at P=0.65-0.8 GPa, T=710-725° C. In the shear zones, recrystallization of perthites is localized along intracrystalline bands. The bands are parallel to shear microcracks and to trails of amphibole and biotite, interpreted as healed microcracks. Fracturing preferentially occurred (but non necessarily) along the excellent cleavage planes (010) and (001). EBSD analysis of perthite porphyroclasts indicates a very low degree of internal misorientation (within 5°) and the lack of recovery features. Recrystallized grains show coarsening with increasing width of the bands, and chemical changes with respect to the host grains (e.g. An14 in the recrystallized grains vs. An22 in the hosting perthites). Crystallographic orientation of the new grains does not show a host-control relation to the parent perthite grains. In summary, there is no evidence for dominant dislocation creep deformation, and the microstructure and CPO data consistently indicate an intragranular recrystallization of perthite by nucleation and growth processes along microcracks. Perthite porphyroclasts are surrounded by a matrix of recrystallized plagioclase + K-feldspar (average grain size of 25 μm) ± amphibole. Amphibole and K-feldspar commonly occur at triple and quadruple junctions between plagioclase grains. There is extensive evidence of phase boundary migration in the matrix, with plagioclase grains forming bulges and protrusions towards K-feldspar. The phase boundaries between K-feldspar and plagioclase are more frequent than grain boundaries, indicating that feldspars are well intermixed in the matrix. Phase boundaries occur with a high density in a C'-type shear band orientation. These observations are consistent with diffusion creep as the dominant deformation mechanism in the matrix, associated with grain boundary sliding and syndeformational nucleation of

  20. The Petrology and Geochemistry of Feldspathic Granulitic Breccia NWA 3163: Implications for the Lunar Crust

    NASA Technical Reports Server (NTRS)

    McLeod, C. L.; Brandon, A. D.; Lapen, T. J.; Shafer, J. T.; Peslier, A. H.; Irvine, A. J.

    2013-01-01

    Lunar meteorites are crucial to understand the Moon s geological history because, being samples of the lunar crust that have been ejected by random impact events, they potentially originate from areas outside the small regions of the lunar surface sampled by the Apollo and Luna missions. The Apollo and Luna sample sites are contained within the Procellarum KREEP Terrain (PKT, Jolliff et al., 2000), where KREEP refers to potassium, rare earth element, and phosphorus-rich lithologies. The KREEP-rich rocks in the PKT are thought to be derived from late-stage residual liquids after approx.95-99% crystallization of a lunar magma ocean (LMO). These are understood to represent late-stage liquids which were enriched in incompatible trace elements (ITE) relative to older rocks (Snyder et al., 1992). As a consequence, the PKT is a significant reservoir for Th and KREEP. However, the majority of the lunar surface is likely to be significantly more depleted in ITE (84%, Jolliff et al., 2000). Lunar meteorites that are low in KREEP and Th may thus sample regions distinct from the PKT and are therefore a valuable source of information regarding the composition of KREEP-poor lunar crust. Northwest Africa (NWA) 3163 is a thermally metamorphosed ferroan, feldspathic, granulitic breccia composed of igneous clasts with a bulk anorthositic, noritic bulk composition. It is relatively mafic (approx.5.8 wt.% FeO; approx.5 wt.% MgO) and has some of the lowest concentrations of ITEs (17ppm Ba) compared to the feldspathic lunar meteorite (FLM) and Apollo sample suites (Hudgins et al., 2011). Localized plagioclase melting and incipient melting of mafic minerals require localized peak shock pressures in excess of 45 GPa (Chen and El Goresy, 2000; Hiesinger and Head, 2006). NWA 3163, and paired samples NWA 4481 and 4883, have previously been interpreted to represent an annealed micro-breccia which was produced by burial metamorphism at depth in the ancient lunar crust (Fernandes et al., 2009

  1. Preliminary Analysis of Borosilicate Minerals in Pegmatitic Leucosomes within Aluminous Granulites at Ledge Mountain, Central Adirondack Highlands, New York

    NASA Astrophysics Data System (ADS)

    Gervais, S. M.; Metzger, E. P.

    2011-12-01

    The borosilicates tourmaline and dumortierite have been identified by polarized light microscopy and electron microprobe analysis in anatectic abyssal-type pegmatites within aluminum-rich granulite-facies migmatites at Ledge Mountain, Central Adirondacks, New York. No other boron-bearing minerals are found in these rocks, and neither borosilicate has been found in the adjacent host gneiss. Tourmaline is ubiquitous in the granulite and upper amphibolite-facies metamorphic rocks of the Central Adirondacks. Dumortierite has been reported from pegmatites of the Batchellerville Province of the Southern Adirondacks, approximately 66 km to the southeast of Ledge Mountain, but not previously at this locality. The tourmaline is alkali dravite-schorl with Mg# = 0.49- 0.53. It is present as anhedral grains less than 2 mm wide intergrown with perthitic microcline and quartz, and as euhedral megacrysts several centimeters in diameter. The dumortierite is strongly pleochroic, ranging from deep indigo blue and violet to colorless. Two strikingly different habits of dumortierite coexist within centimeters of one another in the same sample: bundles of fine prisms less than a few tenths of a millimeter across, and larger granular intergrowths with quartz and chlorite. Apatite and xenotime are also present in both leucosomes and melanosomes, indicating phosphate-enrichment and yttrium in the granulites. According to experimentally determined fields of stability for boron-bearing minerals, the presence of tourmaline and dumortierite and absence of other boron-bearing minerals, especially prismatine, in the pegmatites is consistent with estimated metamorphic conditions of approximately 695-770°C and 7.4-8.2 kbar, as previously determined for this locality using garnet-biotite thermometry and GASP barometry (Boone, 1978). The presence of borosilicates in the leucosomes of these migmatites and the conspicuous lack of them in the paleosome may suggest destabilization of boron

  2. (222)Rn activity concentration differences in groundwaters of three Variscan granitoid massifs in the Sudetes (NE Bohemian Massif, SW Poland).

    PubMed

    Przylibski, Tadeusz A; Gorecka, Joanna

    2014-08-01

    Based on research conducted in three Variscan granitoid massifs located within the crystalline Bohemian Massif, the authors confirmed that the higher the degree of their erosional dissection, the smaller the concentration of (222)Rn in groundwaters circulating in these massifs. This notion implies that radon waters and high-radon waters, from which at least some of the dissolved radon should be removed before feeding them as drinking water to the water-supply system, could be expected in granitoid massifs which have been poorly exposed by erosion. At the same time, such massifs must be taken into account as the areas of possible occurrence of radon medicinal waters, which in some countries can be used for balneotherapy in health resorts. Slightly eroded granitoid massifs should be also regarded as very probable radon prone areas or areas of high radon potential. PMID:24657989

  3. (222)Rn activity concentration differences in groundwaters of three Variscan granitoid massifs in the Sudetes (NE Bohemian Massif, SW Poland).

    PubMed

    Przylibski, Tadeusz A; Gorecka, Joanna

    2014-08-01

    Based on research conducted in three Variscan granitoid massifs located within the crystalline Bohemian Massif, the authors confirmed that the higher the degree of their erosional dissection, the smaller the concentration of (222)Rn in groundwaters circulating in these massifs. This notion implies that radon waters and high-radon waters, from which at least some of the dissolved radon should be removed before feeding them as drinking water to the water-supply system, could be expected in granitoid massifs which have been poorly exposed by erosion. At the same time, such massifs must be taken into account as the areas of possible occurrence of radon medicinal waters, which in some countries can be used for balneotherapy in health resorts. Slightly eroded granitoid massifs should be also regarded as very probable radon prone areas or areas of high radon potential.

  4. Gallium and germanium geochemistry during magmatic fractionation and post-magmatic alteration in different types of granitoids: a case study from the Bohemian Massif (Czech Republic)

    NASA Astrophysics Data System (ADS)

    Breiter, Karel; Gardenová, Nina; Kanický, Viktor; Vaculovič, Tomáš

    2013-06-01

    Contents of Ga and Ge in granites, rhyolites, orthogneisses and greisens of different geochemical types from the Bohemian Massif were studied using inductively coupled plasma mass spectrometry analysis of typical whole-rock samples. The contents of both elements generally increase during fractionation of granitic melts: Ga from 16 to 77 ppm and Ge from 1 to 5 ppm. The differences in Ge and Ga contents between strongly peraluminous (S-type) and slightly peraluminous (A-type) granites were negligible. The elemental ratios of Si/1000Ge and Al/1000Ga significantly decreased during magmatic fraction: from ca. 320 to 62 and from 4.6 to 1.2, respectively. During greisenization, Ge is enriched and hosted in newly formed hydrothermal topaz, while Ga is dispersed into fluid. The graph Al/Ga vs. Y/Ho seems to be useful tool for geochemical interpretation of highly evolved granitoids.

  5. Remelting of nanogranites in peritectic garnet from granulites of Jubrique, Betic Cordillera, Southern Spain

    NASA Astrophysics Data System (ADS)

    Barich, Amel; Bartoli, Omar; Acosta-Vigil, Antonio; Poli, Stefano; Cesare, Bernardo; Garrido, Carlos J.

    2014-05-01

    Peritectic minerals in migmatites can trap droplets of melt that form via incongruent melting reactions during crustal anatexis [1]. In most cases, these melts crystallize and form nanogranites upon slow cooling of the anatectic terrane [2]. To obtain information on the primary compositions of crustal melts, including volatile concentrations in melt and information on fluid regimes, nanogranites must be remelted and rehomogenized before analysis [3]. A new occurrence of nanogranites was recently reported in granulitic gneisses at the bottom of the prograde metamorphic sequence of Jubrique, located on top of the Ronda peridotite slab (Betic Cordillera, S Spain) [4]. These nanogranites are trapped in garnet porphyroblasts. They show partially irregular to well facetted negative crystal shapes, and have variable size from ~5-10 μm to several tens of μm or even ~200 μm in diameter. They appear at the core and rim of large Grt crystals, and are composed of rare glass, daughter Qz, Pl, Kfs, Bt and Ms, and solid inclusions of Ky and less frequently Gr, Hc, Rt, Ilm, Zrn and Mnz. Ky was the main solid phase that favored the trapping of melt inclusions (MI) by poisoning crystal surfaces during Grt growth. The presence of Ky+Rt within MI, and their occurrence in the high-P cores of Grt, suggest that partial melting in the gneisses initiated at relatively high P conditions, and that most Grt in these rocks crystallized in the presence of melt. To recover the major and trace element composition of the primary melt during anatexis, we performed remelting experiments on chips of MI-bearing Grt separated from a sample of gneiss at Jubrique, using a piston cylinder apparatus. Experiments were run at 800, 825 and 850° C, 15 Kbar and dry conditions (i.e. no added H2O) for 24 hrs. Preliminary results of the first experiment at 850º show that nanogranites have been successfully remelted; they all contain glass regardless of their textural position, i.e. at the core and rim of

  6. Constraining long-term denudation and faulting history in intraplate regions by multisystem thermochronology: An example of the Sudetic Marginal Fault (Bohemian Massif, central Europe)

    NASA Astrophysics Data System (ADS)

    DanišíK, Martin; Å TěPančíKová, Petra; Evans, Noreen J.

    2012-04-01

    The Rychlebské hory Mountain region in the Sudetes (NE Bohemian Massif) provides a natural laboratory for studies of postorogenic landscape evolution. This work reveals both the exhumation history of the region and the paleoactivity along the Sudetic Marginal Fault (SMF) using zircon (U-Th)/He (ZHe), apatite fission track (AFT), and apatite (U-Th)/He (AHe) dating of crystalline basement and postorogenic sedimentary samples. Most significantly, and in direct contradiction of traditional paleogeographic reconstructions, this work has found evidence of a large Cretaceous sea and regional burial (to >6.5 km) of the Carboniferous-Permian basement in the Late Cretaceous (˜95-80 Ma). During the burial by sediments of the Bohemian Cretaceous Basin System, the SMF acted as a normal fault as documented by offset ZHe ages across the fault. At 85-70 Ma, the basin was inverted, Cretaceous strata eroded, and basement blocks were exhumed to the near surface at a rate of ˜300 m/Ma as evidenced by Late Cretaceous-Paleocene AFT ages and thermal modeling results. There is no appreciable difference in AFT and AHe ages across the fault, suggesting that the SMF acted as a reverse fault during exhumation. In the late Eocene-Oligocene, the basement was locally heated to <70°C by magmatic activity related to opening of the Eger rift system. Neogene or younger thermal activity was not recorded in the thermochronological data, confirming that late Cenozoic uplift and erosion of the basement blocks was limited to less than ˜1.5 km in the study area.

  7. Underground electromagnetic activity in two regions with contrasting seismicity: a case study from the Eastern Alps and Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Baroň, Ivo; Koktavý, Pavel; Stemberk, Josef; Macků, Robert; Trčka, Tomáš; Škarvada, Pavel; Lenhardt, Wolfgang; Meurers, Bruno; Rowberry, Mattew; Marti, Xavi; Plan, Lukas; Grasemann, Berhnard; Mitrovic, Ivanka

    2016-04-01

    Electromagnetic emissions (EME) occur during the fracturing of solid materials under laboratory conditions and may represent potential earthquake precursors. We recorded EME from May 2015 to October 2015 in two caves situated in contrasting seismotectonic settings. Zbrašov Aragonite Caves are located close to the seismically quiescent contact between the Bohemian Massif and the Outer Western Carpathians while Obir Caves are located near the seismically active Periadriatic Fault on the southern margin of the Eastern Alps. The specific monitoring points are located at depths of tens of metres below the ground surface as such places are assumed to represent favourably shielded environments. The EME signals were continuously monitored by two custom-made Emission Data Loggers (EDLOG), comprising both analogue and digital parts. The crucial analogue component within the EDLOG is a wideband shielded magnetic loop antenna. To be able to observe EME related rock deformation and microfracturing we recorded signals between 10 and 200 kHz with a sampling frequency of 500 kHz. An ultralow noise preamplifier placed close to the antenna increases the signal-to-noise ratio. Further signal processing consisted of filtering, such as antialiasing and interference rejection, and additional amplification to fit the signal to the full scale range of the AD convertor. The digital part of the EDLOG comprises a range of PC components such as high-capacity replaceable data storage and unbuffered RAM, high-speed multichannel DAQ cards, and custom made control software in the programming environment LabVIEW. During our EME monitoring all the raw data were stored. This has allowed us to perform advanced data processing and detailed analysis. During the study period some artificial EME signals were observed in Zbrašov Aragonite Caves. This artificial noise may have overprinted any natural signals and is most likely to relate to the pumping of CO2. In contrast, markedly different signals were

  8. Onset of the Sveconorwegian orogeny: 1220-1130 Ma bimodal magmatism, sedimentation and granulite-facies metamorphism

    NASA Astrophysics Data System (ADS)

    Bingen, Bernard; Viola, Giulio; Engvik, Ane K.; Solli, Arne

    2013-04-01

    indicates that Kongsberg was linked to Telemarkia, before 1147 Ma and before their final tectonic juxtaposition. A similar pattern is known between the Bamble and Telemarkia terranes, indicating similar relations. (4) The classical medium pressure granulite-facies metamorphism in Tromøy-Arendal, Bamble, was redated. Three granulite samples show metamorphic zircon at 1147 +/-18 and 1132 +/-7 Ma. Protolith ages between c. 1553 and 1544 Ma demonstrate a Gothian low-K calc-alkaline orthogneiss protolith and question recent interpretations representing the Tromøy complex as an early Sveconorwegian oceanic volcanic arc accreted to the Bamble terrane. (5) A granulite-facies domain was discovered north of Kragerø in Bamble, in an area generally assigned to amphibolites-facies metamorphism. Geothermobarometry and pseudosection calculation using the Grt +Opx +/-Cpx +Pl +Qtz assemblage yield an estimate of about 1.15 GPa and 800°C for peak granulite facies metamorphism. Late clinopyroxene and garnet zoning are consistent with an anticklockwise P-T path and suggest magma loading and heating of the crust. Soccer ball zircon dates this metamorphism at 1144 ±6 Ma. (6) C. 1193-1183 Ma A-type granite plutonism is reported in the Caledonian Middle-Allochthon Risberget Nappe and c. 1221-1204 Ma syenite plutons are known along the Sveconorwegian Frontal Deformation Zone. C. 1220-1130 Ma magmatism is however entirely lacking in the Idefjorden terrane. Using these constraints, we envisage the 1220-1130 Ma pre- to early-Sveconorwegian event in a trans(?)-tensional continental setting at the margin of Baltica, before final continental collision. The Telemarkia terrane was possibly located in a back arc position above an east dipping subduction system. Abundant magmatism is possibly a consequence of subduction of an oceanic ridge. Inversion took place after 1130 Ma leading to westwards thrusting of the Bamble and Kongsberg terranes.

  9. Archaean associations of volcanics, granulites and eclogites of the Belomorian province, Fennoscandian Shield and its geodynamic interpretation

    NASA Astrophysics Data System (ADS)

    Slabunov, Alexander

    2013-04-01

    An assembly of igneous (TTG-granitoids and S-type leucogranites and calc-alkaline-, tholeiite-, kometiite-, boninite- and adakite-series metavolcanics) and metamorphic (eclogite-, moderate-pressure (MP) granulite- and MP amphibolite-facies rocks) complexes, strikingly complete for Archaean structures, is preserved in the Belomorian province of the Fennoscandian Shield. At least four Meso-Neoarchaean different-aged (2.88-2.82; 2.81-2.78; ca. 2.75 and 2.735-2.72 Ga) calc-alkaline and adakitic subduction-type volcanics were identified as part of greenstone belts in the Belomorian province (Slabunov, 2008). 2.88-2.82 and ca. 2.78 Ga fore-arc type graywacke units were identified in this province too (Bibikova et al., 2001; Mil'kevich et al., 2007). Ca.2.7 Ga volcanics were generated in extension structures which arose upon the collapse of an orogen. The occurrence of basalt-komatiite complexes, formed in most greenstone belts in oceanic plateau settings under the influence of mantle plumes, shows the abundance of these rocks in subducting oceanic slabs. Multiple (2.82-2.79; 2.78-2.76; 2.73-2.72; 2.69-2.64 Ga) granulite-facies moderate-pressure metamorphic events were identified in the Belomorian province (Volodichev, 1990; Slabunov et al., 2006). The earliest (2.82-2.79 Ga) event is presumably associated with accretionary processes upon the formation of an old continental crust block. Two other events (2.78-2.76; 2.73-2.72 Ga) are understood as metamorphic processes in suprasubduction setting. Late locally active metamorphism is attributed to the emplacement of mafic intrusions upon orogen collapse. Three groups of crustal eclogites with different age were identified in the Belomorian province: Mesoarchaean (2.88-2.86 and 2.82-2.80 Ga) eclogites formed from MORB and oceanic plateau type basalts and oceanic high-Mg rocks (Mints et al., 2011; Shchipansky at al., 2012); Neoarchaean (2.72 Ga) eclogites formed from MORB and oceanic plateau type basalts. The formation of

  10. Structural framework across the Bastar craton - the Eastern Ghats Granulite Belt interface: Implications for making of eastern Gondwana

    NASA Astrophysics Data System (ADS)

    Patole, Vishal; Nasipuri, Pritam

    2015-04-01

    The transformation of palaeo-continents involve breakup, dispersal and reassembly of cratonic blocks by collisional suturing that develop a network of orogenic (mobile) belts around the periphery of the stable cratons. During the collision, partial melting of the different crustal blocks produces migmatites at the craton-mobile belt interface. Thus, migmatites at the craton-mobile belt contact can provide valuable information regarding the pressure-temperature conditions of the melting of lower crust during supercontinent building processes. In this contribution, we document the structural framework across the Bastar craton- Eastern Ghats Granulite Belt (EGGB) interface that developed during the accretion of EGGB over Bastar craton. Near Bhawanipatna, Orissa, Eastern India, the granulites of the mobile belt are juxtaposed against the granitic rocks of the Bastar craton. Away from the contact domain, the cratonic granite is non-migmatitic and blasto-porphyritic in nature that gradually transforms to migmatitic variety towards the contact domain. In the non-migmatitic variety, the E-W trending stromatic leucozomes and biotite-hornblende rich fabric (S1) wraps around recrystallized K-feldspar augens. In the migmatitic variety towards the contact domain, NNE-SSW trending diatexite leucozomes (S2) are prominent and the intensity of melting and tightness of folding increases towards the contact domain. Structural measurements indicate that the S1 fabric is folded with the development of NNE-SSW axial plane with easterly plunging fold axis (50 -> 050N). To correlate the geological history of EGGB in the context of supercontinent reconstruction, the existence of a cratonic block consisting of India - Madagascar - Sri Lanka - Enderby Land-Kalahari ("IMSLEK") from 3000 Ma upto 750 Ma has been invoked by several authors. The apparent continuity of the Grenvillian metamorphic orogen along the East Antarctica-Australia-India margin has been taken as conclusive evidence for the

  11. P-T-t path for the Archean Pikwitonei Granulite Domain and Cross Lake Subprovince, Manitoba, Canada

    NASA Technical Reports Server (NTRS)

    Mezger, K.; Bohlen, S. R.; Hanson, G. N.

    1988-01-01

    The rationale was outlined for constructing pressure-temperature-time (P-T-t) paths by using U-Pb dating of garnet produced in thermobarometrically sensitive reactions. In an example from the Pikwitonei granulites of the Northwestern Superior Province of the Canadian Shield, garnets were formed at 2744-2742 Ma, 2700-2689 Ma, and 2605-2590 Ma, the latter events coinciding with times recorded by U-Pb zircon systems. Garnet grew during metamorphism at 6.5 kbar, 630 to 750 C and later at 7.2 to 7.5 kbar, 800 C; the later metamorphism apparently did not exceed the U-Pb closure temperature. The resultant P-T-t path is counterclockwise, with late isobaric cooling, interpreted to result from magmatic heating at an Andean margin.

  12. Palaeoproterozoic high-pressure granulite overprint of the Archaean continental crust: evidence for homogeneous crustal thickening (Man Rise, Ivory Coast)

    NASA Astrophysics Data System (ADS)

    Pitra, Pavel; Kouamelan, Alain N.; Ballèvre, Michel; Peucat, Jean-Jacques

    2010-05-01

    The character of mountain building processes in the Palaeoproterozoic times is subject to much debate. The local observation of Barrovian-type assemblages and high-pressure granulite relics in the Man Rise (Côte d'Ivoire), led some authors to argue that Eburnean (Palaeoproterozoic) reworking of the Archaean basement was achieved by modern-style thrust-dominated tectonics (e.g., Feybesse & Milési, 1994). However, it has been suggested that crustal thickening and subsequent exhumation of high-pressure crustal rocks can be achieved by virtue of homogeneous, fold-dominated deformation of hot crustal domains even in Phanerozoic orogenic belts (e.g., Schulmann et al., 2002; 2008). We describe a mafic granulite of the Kouibli area (Archaean part of the Man Rise, western Ivory Coast) that displays a primary assemblage (M1) containing garnet, diopsidic clinopyroxene, red-brown pargasitic amphibole, plagioclase (andesine), rutile, ilmenite and quartz. This assemblage is associated with a subvertical regional foliation. Symplectites that develop at the expense of the M1 assemblage contain orthopyroxene, clinopyroxene, plagioclase (bytownite), green pargasitic amphibole, ilmenite and magnetite (M2). Multiequilibrium thermobarometric calculations and P-T pseudosections calculated with THERMOCALC suggest granulite-facies conditions of ca. 13 kbar, 850°C and <7 kbar, 700-800°C for M1 and M2, respectively. In agreement with the qualitative information obtained from reaction textures and chemical zoning of minerals, this suggests an evolution dominated by decompression accompanied by moderate cooling. A Sm-Nd garnet - whole-rock age of 2.03 Ga determined on this sample indicates that this evolution occurred during the Palaeoproterozoic. We argue that from the geodynamic point of view the observed features are best explained by homogeneous thickening of the margin of the Archaean craton, re-heated and softened due to the accretion of hot, juvenile Palaeoproterozoic crust, as

  13. Generation of trondhjemite from partial melting of dacite under granulite facies conditions: an example from the New Jersey Highlands, USA

    USGS Publications Warehouse

    Puffer, J.H.; Volkert, R.A.

    1991-01-01

    New field and geochemical data place the Losee Metamorphic Suite (a tonalite/trondhjemite complex) of northern New Jersey into the context of a major Proterozoic continental are represented by a discontinuous belt of northern Appalachian metadacite. Samples of Losee rock range from extremely leucocratic trondhjemite locally associated with amphibolite, to banded biotite, hornblende, pyroxene, and garnet-bearing tonalites. The major element and REE composition of the tonalite closely resembles dacite from continental are settings and model melts extracted from an eclogite residue by partial melting at 15 kbar. The REE composition of most Losee trondhjemite is enriched in REE, particularly HREE, compared with Losee tonalite, and is interpreted as the product of local anatectic melting of Losee tonalite (metadacite) that occurred in a granulite facies environment during the Grenville orogeny. ?? 1991.

  14. Provenance of the Lapland Granulite Belt: evidence for silicic crustal acretion at 2.1-1.97 Ga

    NASA Astrophysics Data System (ADS)

    Tuisku, Pekka; Huhma, Hannu

    2003-04-01

    SIMS was used to reveal the provenance of Lapland Granulite Belt metasediments, now appearing as migmatitic granulites. Majority of the detrital grains in two outcrops studied fall in the age group 1.97-2.0 Ga, the medians are at 2015 and 2039Ma. The detrital grains are similar to those found in silicic plutonic and volcanic rocks. Because the LGB has great area extend, about 400 times 90 km, and because other studies (Sorjonen-Ward et. al., 1994, Claesson et. al, 1993) give similar results, it is concluded that there must have been a relatively large acid igneous province active between 1.97-2.1 Ga, which has eroded and then fed the sedimentary material for the LGB sediments and other comparable metasediments in the Fennoscandian shield. The Sm-Nd DM model age of the LGB metasediments is between 2300-2380 Ma. This also a common model age elsewhere in the shield. This kind of model age may be obtained by mixing of Svecofennian (1.9Ga) and Archaean material, as has been proposed earlier. However, considering the provenance of zircons, it is also possible to construct the model age by mixing Archaean and Palaeoproterozoic 2.0-2.1 Ga material; and possibly also Svecofennian ~1.9 Ga material as some, apparently relatively young detrital grains around 1.93-1.95 were found in the LGB metasediments. The major problem arises from the fact that there is no major outcropped acid igneous province of that age in the Fennoscandian Shield, and neither are such rocks common elsewhere in the world.

  15. Geochronology of granulite, charnockite and gneiss in the poly-metamorphosed Gaozhou Complex (Yunkai massif), South China: Emphasis on the in-situ EMP monazite dating

    NASA Astrophysics Data System (ADS)

    Chen, Cheng-Hong; Liu, Yung-Hsin; Lee, Chi-Yu; Xiang, Hua; Zhou, Han-Wen

    2012-07-01

    The in-situ EMP (electron microprobe) monazite age dating performed directly in the polished sections, in addition to the conventional U-Pb zircon and EMP monazite age dating on grains from heavy mineral concentrates, has been applied to the granulite, charnockite and gneiss in the Gaozhou Complex of the Yunkai massif in South China. While the conventional dating systems all give Caledonian ages, the in-situ EMP monazite ages provide more information to reveal not only detailed age groups pertaining to the Caledonian orogeny but also traces of later thermal events overprinting these rocks. For granulites, although some monazites present zoning (concentric, patchy and complex) in the BSE images, no discernable age differences are observed. Resetting of the Th-U-Pb monazite dating system under the high temperature condition could be the reason. Ages of homogeneous monazite in garnet porphyroblast (ca. 440 Ma) of the garnet-cordierite granulite that match nicely with the U-Pb zircon ages are systematically older than those in the matrix (ca. 430 Ma). The same case of two age groups is also present in the orthopyroxene-biotite granulite as revealed by monazite inclusions in plagioclase and orthopyroxene and those in quartz, respectively. For charnockites, despite similar ages of ca. 430 Ma are given by monazite in biotite and zircon in the rock, significant younger ages are obtained from monazites with particular features. Relict monazites with a breakdown texture to form successive layers of apatite and allanite in the rim as well as those which are close to the biotite-chlorite microvein always show a similar age of ca. 230 Ma. Moreover, tiny monazites in close association with the garnetiferous corona mainly surrounding orthopyroxene give rise to another age group around 370 Ma. For gneissic rocks, monazites enclosed by quartz give 434 Ma and those setting in the chlorite-epidote microvein of a paragneiss yield 237 Ma, consistent with the U-Pb zircon core-rim age

  16. Pan-African high pressure granulites from SE-Kenya: Petrological and geothermobarometric evidence for a polycyclic evolution in the Mozambique belt

    NASA Astrophysics Data System (ADS)

    Hauzenberger, C. A.; Bauernhofer, A. H.; Hoinkes, G.; Wallbrecher, E.; Mathu, E. M.

    2004-12-01

    Two different Pan-African tectono-metamorphic events are recognised in the Taita Hill Tsavo East National Park/Galana river area, SE-Kenya (Mozambique belt) based on petrographic and geothermobarometric evidence. Structurally, this area can be subdivided into four units: (1) the easternmost part of the basement along the Galana river is characterized by subhorizontal slightly to the west and east dipping foliation planes. Migmatic paragneisses with intercalated marbles, calcsilicates and metapelites and bands of amphibolites are the dominant rock type. (2) The western part of the Galana river within the Tsavo East National Park is a ca. 25 km wide shear zone with subvertical foliation planes. The eastern part shows similar rocks as observed in unit 1, while towards west, metasedimentary units become rare and the main rock types are tonalitic gneisses with intercalated amphibolites. (3) A 10 km wide zone (Sagala Hills zone) between the strike slip zone (unit 2) and the Taita Hills (unit 4) is developed. This zone is characterized by elongated and folded felsic migmatic amphibole and garnet bearing orthogneiss bodies with intercalated bands of mafic rocks. (4) The Taita Hills are a slightly to the N dipping nappe stack. The main rock type in the Taita Hills are amphibole-biotite-plagioclase-quartz ± garnet ± clinopyroxene ± scapolite bearing migmatic gneisses with mafic bands. In the southern part, metapelites, marbles and some amphibolites are common. Although the geological structures are different in units 1 and 2, the calculated PT conditions are similar with peak PT of 760-820 °C and 7.5-9.5 kbar. Temperatures in unit 3 (Sagalla Hills zone) and unit 4 (Taita Hills) are slightly higher ca. 760-840 °C, but pressure is significantly higher, ranging from 10 to 12 kbar. Sillimanite growth around kyanite, garnet zonation pattern, mineral reaction textures, and PT calculations constrain a "clock-wise" PT-path with near isobaric cooling following the peak of

  17. Improved assessment of P-T paths from combined Zr-in-rutile thermometry and major phase element zoning: An example from UHT granulites of the Gruf Complex, Central Alps

    NASA Astrophysics Data System (ADS)

    Oalmann, J.; Moeller, A.; Bousquet, R.

    2012-12-01

    Combining major element compositions of major minerals with accessory phase thermometry can provide robust constraints on the P-T evolution of polymetamorphic rocks. The Gruf Complex in the Lepontine Alps has experienced UHT metamorphism and an upper amphibolite to lower granulite facies overprint. Migmatitic orthogneisses are the volumetrically dominant rock type in the Gruf Complex, but charnockites and rare sapphirine-bearing granulites preserve UHT mineral assemblages. Distinct types of granulites include: 1) massive, Al- and Mg-rich granulites; 2) foliated, stromatic granulites; 3) foliated, leucocratic granulites; 4) massive to foliated retrogressed granulites. X-ray compositional maps were obtained by electron microprobe to characterize porphyroblasts in the different granulite types. Trace element compositions of rutile inclusions and matrix grains were determined by LA-ICP-MS, and Zr-in-rutile temperatures were calculated. Large (up to 2 cm) garnet porphyroblasts within residual granulites contain inclusion-rich inner zones and inclusion-poor outer zones. In the inner zones, Fe and Ca contents increase toward the outer zones, whereas Mg content decreases. The outer zones are characterized by concave-up Fe profiles and concave-down Mg profiles. These complex profiles possibly indicate at least two stages of garnet growth, with modification of inner zone growth zoning by diffusion during the second growth stage. Rutile inclusions in garnet record temperatures from 600-900°C, potentially spanning the full temperature range of garnet growth. In the stromatic granulites, garnet porphyroblasts exhibit concentric zoning characterized by increasing Mg and decreasing Fe, Ca, and Mn contents from core to rim. Rutile inclusions in garnet crystallized from 500-700°C, whereas rutile grains in symplectites around garnet porphyroblasts record UHT conditions. Leucocratic granulites are characterized by semi-atoll garnet porphyroblasts in which garnet is partly consumed

  18. LILE, REE, and HFSE partition coefficients between crystal and melt in migmatites of granulite facies of the Nimnyr block, Aldan shield

    NASA Astrophysics Data System (ADS)

    Glebovitskii, V. A.; Sedova, I. S.

    2015-05-01

    The behavior of Rb, Sr, Ba, Cr, V, Nb, Zr, REEs, and Y is studied in migmatites of granulite facies and the transitional zone to amphibolite facies in the western part of the Aldan granulite area. Our data allowed estimation of the partition coefficients of these elements in the crystal-melt system ( D i ) for orthopyroxene, garnet, clinopyroxene, and hornblende. The leucosomes of anatectic migmatites and diatectites (high-K charnockites and granites) were accepted as a melt, and the metapelites or previously granitized rocks (nebulites) and early leucosomes relative to late leucosome were the primary rocks and restite. The dependence of D i on the REE ionic radius is close to parabolic [7]. Our data allow identification of a qualitative link between the D {/i Grt/melt} and the thermodynamic conditions of high-grade metamorphism and the accompanying partial melting, which leads to formation of a series of ultrametamorphic granitic rocks: lower temperature rocks (conditions of amphibolite facies) are characterized by higher D REE values relative to the zone of granulite facies. The late granitic rocks formed after diatectic charnockites are also characterized by higher D REE values relative to the preceding charnockites. For the conditions of granulite facies, the material belongs to rocks similar in the formation conditions; however, the series are strongly distinct in K content. The influence of the composition of the anatectic melt and acidity-alkalinity conditions on the partition coefficients of the studied elements is so strong that it eliminates the effect of temperature and pressure. The LREEs, Rb, Sr, and Ba will mostly accumulate in the garnet-orthopyroxene assemblage in the zone of melt origination, whereas HREEs will remain in restite along with Cr and V. Niobium and Zr may enrich the granitic melts. In contrast, the stability of amphibole in restite causes the depletion of melts in all REEs, Y, and Nb and enrichment in Rb, Sr, Ba, and, to a lesser

  19. The timing of eclogite facies metamorphism and migmatization in the Orlica–Śnieżnik complex, Bohemian Massif: Constraints from a multimethod geochronological study

    USGS Publications Warehouse

    Brocker, M.; Klemd, R.; Cosca, M.; Brock, W.; Larionov, A.N.; Rodionov, N.

    2009-01-01

    The Orlica–Śnieżnik complex (OSC) is a key geological element of the eastern Variscides and mainly consists of amphibolite facies orthogneisses and metasedimentary rocks. Sporadic occurrences of eclogites and granulites record high-pressure (HP) to ultrahigh-pressure (UHP) metamorphic conditions. A multimethod geochronological approach (40Ar–39Ar, Rb–Sr, Sm–Nd, U–Pb) has been used to gain further insights into the polymetamorphic evolution of eclogites and associated country rocks. Special attention was given to the unresolved significance of a 370- to 360 Ma age group that was repeatedly described in previous studies. Efforts to verify the accuracy of c.370 Ma K–Ar phengite and biotite dates reported for an eclogite and associated country-rock gneiss from the location Nowa Wieś suggest that these dates are meaningless, due to contamination with extraneous Ar. Extraneous Ar is also considered to be responsible for a significantly older 40Ar–39Ar phengite date of c. 455 Ma for an eclogite from the location Wojtowka. Attempts to further substantiate the importance of 370–360 Ma zircon dates as an indicator for a melt-forming high-temperature (HT) episode did not provide evidence in support of anatectic processes at this time. Instead, SHRIMP U–Pb zircon dating of leucosomes and leucocratic veins within both orthogneisses and (U)HP granulites revealed two age populations (490–450 and 345–330 Ma respectively) that correspond to protolith ages of the magmatic precursors and late Variscan anatexis. The results of this study further underline the importance of Late Carboniferous metamorphic processes for the evolution of the OSC that comprise the waning stages of HP metamorphism and lower pressure HT overprinting with partial melting. Eclogites and their country rocks provided no chronometric evidence for an UHP and ultrahigh-temperature episode at 387–360 Ma, as recently suggested for granulites from the OSC, based on Lu–Hf garnet

  20. Petrographical Evidence for Ultra High Temperature Metamorphism from Sapphirine-bearing Granulites; the Central Highland Complex Sri Lanka

    NASA Astrophysics Data System (ADS)

    Dharmapriya, P. L.; Malaviarachchi, S.

    2013-05-01

    Extreme crustal metamorphism at temperatures of 900-1150 0C generates rocks with specific mineralogical characteristics termed as ultra high temperature (UHT) granulites. UHT conditions have been derived and inferred from Sapphirine-bearing granulites throughout the world including Sri Lanka. In this study we put forward petrographical evidence for UHT metamorphism observed in thin sections of four types of sapphirine-bearing granulites. Sapphirine (Spr), Kayanite (Ky) (?) and Spinel (Spl) bearing Garnet (Grt)- Orthopyroxene (Opx)-Sillimanite (Sil)-Cordiarite (Cord)-Biotite (Bt) gneiss (Rock A) collected from quarry close to Gampola where the rock is occurred as a layer within Sapphirine bearing Grt-Opx-Sil- Bt gneiss (Rock B). In Rock A, anhedral Spr grains are founded in two phases; as inclusion with in core area of porphyroblastic Grt and within the Quartz (Qtz) saturated matrix. Former type is coexisting with Ky (?) while later types where Spr grain close to Grt porpyroblasts associated with Plagioclase (Plag)-Opx and Spr grain away from garnets are coexisting with K-feldspar and Plag. There are plenty of retrograde Opx+Sil+Cord intergrowth in the matrix of Rock A could be the Spr+Qtz brake down product after the peak metamorphism via the reaction Spr+Qtz=Opx+Sil+Qtz. In Rock B, Spr comprise as inclusion within Grt as mono-phase. Multiple modes of occurrences of Opx-Sil-Qtz assemblage can also be observed in both Rocks A and B enhance that the rocks have been evolved through UHT conditions. Spr, Spl and Sil bearing Grt-Opx-Bt gneiss (Rock C) was collected from a quarry close Kotmale where the rock is occur as a thin layer within a massive charnockite. The Rock C contains medium grained Grt porphyroblasts in which Spr, Spl, Sil, Rutile, Qtz and Bt occur as rare inclusions as either monophase or multiphase assemblages. Spr and Spl have coexisted with tiny mineral which shows inclined extinction and low order birefringence it is very difficult to identify. Based

  1. Chevkinite-group minerals from granulite-facies metamorphic rocks and associated pegmatites of East Antarctica and South India

    USGS Publications Warehouse

    Belkin, H.E.; Macdonald, R.; Grew, E.S.

    2009-01-01

    Electron microprobe data are presented for chevkinite-group minerals from granulite-facies rocks and associated pegmatites of the Napier Complex and Mawson Station charnockite in East Antarctica and from the Eastern Ghats, South India. Their compositions conform to the general formula for this group, viz. A4BC2D2Si4O22 where, in the analysed specimens A = (rare-earth elements (REE), Ca, Y, Th), B = Fe2+, Mg, C = (Al, Mg, Ti, Fe2+, Fe3+, Zr) and D = Ti and plot within the perrierite field of the total Fe (as FeO) (wt.%) vs. CaO (wt.%) discriminator diagram of Macdonald and Belkin (2002). In contrast to most chevkinite-group minerals, the A site shows unusual enrichment in the MREE and HREE relative to the LREE and Ca. In one sample from the Napier Complex, Y is the dominant cation among the total REE + Y in the A site, the first reported case of Y-dominance in the chevkinite group. The minerals include the most Al-rich yet reported in the chevkinite group (49.15 wt.% Al2O3), sufficient to fill the C site in two samples. Conversely, the amount of Ti in these samples does not fill the D site, and, thus, some of the Al could be making up the deficiency at D, a situation not previously reported in the chevkinite group. Fe abundances are low, requiring Mg to occupy up to 45% of the B site. The chevkinite-group minerals analysed originated from three distinct parageneses: (1) pegmatites containing hornblende and orthopyroxene or garnet; (2) orthopyroxene-bearing gneiss and granulite; (3) highly aluminous paragneisses in which the associated minerals are relatively magnesian or aluminous. Chevkinite-group minerals from the first two parageneses have relatively high FeO content and low MgO and Al2O3 contents; their compositions plot in the field for mafic and intermediate igneous rocks. In contrast, chevkinite-group minerals from the third paragenesis are notably more aluminous and have greater Mg/Fe ratios. ?? 2009 The Mineralogical Society.

  2. Element Transport in Granulite-Facies Fluids: a TEM Study in Exsolved Ternary Feldspar From Charnockites of Lofoten, Norway

    NASA Astrophysics Data System (ADS)

    Hartmann, K. T.; Wirth, R.; Markl, G.

    2006-12-01

    TEM was used to study exsolution features in feldspars indicative of high-p-T fluid transport during granulite facies metamorphism in charnockites from the Lofoten Islands in Northern Norway. The protoliths formed about 1750 Ma ago, at about ~800 to 900°C and 4 kbar. During a crustal thickening event, they reached high-pressure granulite-facies conditions of about 8-11 kbar at ~700°C (1). During this event, tiny magmatic pyroxenes enclosed in alkali feldspar reacted with a fluid to Cl-rich amphiboles and biotite. These have always a direct connection to elongated albite exsolutions which seem to surround amphiboles and biotite arranged in a linear fashion. This is evidence of extensive element transport (Fe, H, Cl) through the feldspar. The primary pyroxenes show no spatial relation to the lamellae and are evenly distributed in the feldspars. We tried to unravel the details of the transport and transformation mechanisms recorded by these textures using EMPA and TEM. Focused Ion Beam (FIB) prepared TEM-foils (2) revealed that pyroxenes, when spatially connected to albite exsolutions, show dissolution features. Additionally, amorphous Fe- and Cl-bearing material was found in albite lamellae even when not connected to a pyroxene. Based on composition, nanostructures and the known p-T-history, we propose the following succession of events. Feldspar containing small magmatic pyroxenes began to exsolve between about 800 and 650°C. The exsolution lamellae changed from coherent to incoherent and a fluid infiltrated the feldspar along nanotunnels (see also 3) at the margins of the exsolution lamellae. When the fluid had access to pyroxene, reaction took place and either amphibole or biotite formed. This study shows that fluid migration at elevated p and T is strongly dependent on the mineralogy of the percolated rocks. Exsolving alkali feldspars may offer fluid pathways not yet considered in studies on metamorphic fluid flow which is typically believed to happen along

  3. The evolution of a Gondwanan collisional orogen: A structural and geochronological appraisal from the Southern Granulite Terrane, South India

    NASA Astrophysics Data System (ADS)

    Plavsa, Diana; Collins, Alan S.; Foden, John D.; Clark, Chris

    2015-05-01

    Gondwana amalgamated along a suite of Himalayan-scale collisional orogens, the roots of which lace the continents of Africa, South America, and Antarctica. The Southern Granulite Terrane of India is a generally well-exposed, exhumed, Gondwana-forming orogen that preserves a record of the tectonic evolution of the eastern margin of the East African Orogen during the Ediacaran-Cambrian (circa 600-500 Ma) as central Gondwana formed. The deformation associated with the closure of the Mozambique Ocean and collision of the Indian and East African/Madagascan cratonic domains is believed to have taken place along the southern margin of the Salem Block (the Palghat-Cauvery Shear System, PCSS) in the Southern Granulite Terrane. Investigation of the structural fabrics and the geochronology of the high-grade shear zones within the PCSS system shows that the Moyar-Salem-Attur shear zone to the north of the PCSS system is early Paleoproterozoic in age and associated with dextral strike-slip motion, while the Cauvery shear zone (CSZ) to the south of the PCSS system can be loosely constrained to circa 740-550 Ma and is associated with dip-slip dextral transpression and north side-up motion. To the south of the proposed suture zone (the Cauvery shear zone), the structural fabrics of the Northern Madurai Block suggest four deformational events (D1-D4), some of which are likely to be contemporaneous. The timing of high pressure-ultrahigh temperature metamorphism and deformation (D1-D3) in the Madurai Block (here interpreted as the southern extension of Azania) is constrained to circa 550-500 Ma and interpreted as representing collisional orogeny and subsequent orogenic collapse of the eastern margin of the East African Orogen. The disparity in the nature of the structural fabrics and the timing of the deformation in the Salem and the Madurai Blocks suggest that the two experienced distinct tectonothermal events prior to their amalgamation along the Cauvery shear zone during the

  4. Petrochronological and structural arguments for upper plate thickening and relamination of the lower plate buoyant material in the Variscan Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Peřestý, Vít; Holder, Robert; Lexa, Ondrej; Racek, Martin; Jeřábek, Petr

    2014-05-01

    Recent tectonic models for the Variscan evolution of the Bohemian Massif emphasize the role of Rayleigh-Taylor instability for the 355-340 Ma evolution of the Moldanubian domain. This model is based on the presence of weak, low-density felsic material tectonically underplating a high-density mafic layer and its subsequent gravity-driven overturn. However, earlier phases of the Variscan orogeny concerning the emplacement of felsic low-density material to the base of the upper plate are so far poorly documented. We contribute to this problem by deciphering of polyphase early-Variscan (~375 Ma) deformation and metamorphism close to the main Variscan suture. Detailed structural, pseudosection and microstructural analyses combined with LASS monazite dating were carried out in metapelites along the western margin of the upper plate represented by the Teplá Crystalline Complex (TCC). This region is represented by a ~25 km wide deformation zone with E-W metamorphic gradients associated with two distinct early-Variscan events (~380-375 and ~375-370 Ma). The first compressional event produced a vertical NNE-SSW trending fabric and a continuous and prograde Barrovian metamorphic sequence ranging from biotite to kyanite zones at a field geotherm of 20 to 25 °C/km. Subsequently, a gently SE dipping normal shear-zone associated with retrogression develops along the base of the TCC. This sub-horizontal fabric shows normal metamorphic zonation ranging from sillimanite, biotite to chlorite zones and indicates vertical shortening related to unroofing of high pressure metabasites of the underlying Mariánské-Lázně Complex. The first metamorphic fabric is interpreted to result from early thickening of the upper plate during continental underthrusting of Saxothuringian continent (380 to 375 Ma) while the second deformation and metamorphism (~370 Ma) reflects vertical shortening produced by buoyant uplift of accreted Saxothuringian felsic crust. This event is the unique yet

  5. Brittle deformation in Southern Granulite Terrane (SGT): A study of pseudotachylyte bearing fractures along Gangavalli Shear Zone (GSZ), Tamil Nadu, India.

    NASA Astrophysics Data System (ADS)

    mohan Behera, Bhuban; Thirukumaran, Venugopal; Biswal, Tapas kumar

    2016-04-01

    High grade metamorphism and intense deformation have given a well recognition to the Southern Granulite Terrane (SGT) in India. TTG-Charnockite and basic granulites constitute the dominant lithoassociation of the area. Dunite-peridotite-anorthosite-shonkinite and syenites are the intrusives. TTG-charnockite-basic granulite have undergone F1 (isoclinal recumbent), F2 (NE-SW) and F3 (NW-SE) folds producing several interference pattern. E-W trending Neoarchean and Palaeoproterozoic Salem-Attur Shear Zone exhibits a low angle ductile thrust as well as some foot print of late stage brittle deformation near Gangavalli area of Tamil Nadu. The thrust causes exhumation of basic granulites to upper crust. Thrusting along the decollement has retrograded the granulite into amphibolite rock. Subsequently, deformation pattern of Gangavalli area has distinctly marked by numerous vertical to sub-vertical fractures mostly dominating along 0-15 and 270-300 degree within charnockite hills that creates a maximum stress (σ1) along NNW and minimum stress (σ3) along ENE. However, emplacement of pseudotachylyte vein along N-S dominating fracture indicates a post deformational seismic event. Extensive fractures produce anastomose vein with varying thickness from few millimeters to 10 centimeters on the outcrop. ICP-AES study results an isochemical composition of pseudotachylyte vein that derived from the host charnockitic rock where it occurs. But still some noticeable variation in FeO-MgO and Na2O-CaO are obtained from different parts within the single vein showing heterogeneity melt. Electron probe micro analysis of thin sections reveals the existence of melt immiscibility during its solidification. Under dry melting condition, albitic rich melts are considered to be the most favorable composition for microlites (e.g. sheaf and acicular micro crystal) re-crystallization. Especially, acicular microlites preserved tachylite texture that suggest its formation before the final coagulation

  6. Contrasts in sillimanite deformation in felsic tectonites from anhydrous granulite- and hydrous amphibolite-facies shear zones, western Canadian Shield

    NASA Astrophysics Data System (ADS)

    Leslie, S. R.; Mahan, K. H.; Regan, S.; Williams, M. L.; Dumond, G.

    2015-02-01

    The deformation behavior of crustal materials in variably hydrated metamorphic environments can significantly influence the rheological and seismic properties of continental crust. Optical observations and electron backscatter diffraction (EBSD) analyses are used to characterize sillimanite deformation behavior in felsic tectonites from two deformation settings in the Athabasca granulite terrane, western Canadian Shield. Under estimated conditions of 0.8-1.0 GPa, 725-850 °C in the Cora Lake shear zone, the data suggest that sillimanite deformed by dislocation creep with slip in the [001] direction accompanied by subgrain rotation recrystallization. Where sillimanite locally remained undeformed, strain was concentrated in surrounding weaker phases. Under hydrated conditions of 0.4-0.6 GPa, 550-650 °C in the Grease River shear zone, textures and cathodoluminescence imaging point to dissolution-precipitation creep as the major deformation mechanism for sillimanite, resulting in synkinematic growth of foliation-parallel euhedral sillimanite in a preferred orientation with [001] parallel to the lineation. The results suggest that temperature, fluid content, and modal mineralogy of the surrounding phases may all have significant influence on sillimanite deformation but that preferential alignment of sillimanite [001] parallel to the lineation persists regardless of contrasts in the conditions or mechanisms of deformation.

  7. Kibaran magmatism and Pan-African granulite metamorphism in northern Mozambique: single zircon ages and regional implications

    NASA Astrophysics Data System (ADS)

    Kroner, A.; Sacchi, R.; Jaeckel, P.; Costa, M.

    1997-10-01

    Single zircons from granitoid orthogneisses in the foreland of the Lurio Belt of northern' Mozambique were dated by the evaporation method and yielded 207Pb/ 206Pb magmatic emplacement ages between 1040.1 ±0.4 and 1148.2±0.4 Ma. These data confirm previous RbSr whole rock and SHRIMP zircon analyses and record a period of magmatic activity corresponding to the Kibaran event of east central Africa. A1300 Ma old zircon xenocryst in one sample suggests the presence of still older crust in the region. Metamorphic zircons from a granulite-facies psammopelitic gneiss of the Mugeba klippe, which is derived tectonically from the Lurio Belt, were dated by evaporation, conventional techniques and SHRIMP at ˜615 Ma. This us interpreted as reflecting the peak of high-grade metamorphism in this rock and, by implication, in the Lurio Belt. It is concluded from this that the main metamorphism in the basement of northern Mozambique occured in Pan-African times, as is the case in adjacent regions of Tanzania and Malawi, and that this may be the result of collision between East and West Gondwana

  8. Contrasts in sillimanite deformation in felsic tectonites from anhydrous granulite- and hydrous amphibolite-facies shear zones, western Canadian Shield

    NASA Astrophysics Data System (ADS)

    Leslie, S. R.; Mahan, K. H.; Regan, S.; Williams, M. L.; Dumond, G.

    2015-02-01

    The deformation behavior of crustal materials in variably hydrated metamorphic environments can significantly influence the rheological and seismic properties of continental crust. Optical observations and electron backscatter diffraction (EBSD) analyses are used to characterize sillimanite deformation behavior in felsic tectonites from two deformation settings in the Athabasca granulite terrane, western Canadian Shield. Under estimated conditions of 0.8-1.0 GPa, 725-850 °C in the Cora Lake shear zone, the data suggest that sillimanite deformed by dislocation creep with slip in the [001] direction accompanied by subgrain rotation recrystallization. Where sillimanite locally remained undeformed, strain was concentrated in surrounding weaker phases. Under hydrated conditions of 0.4-0.6 GPa, 550-650 °C in the Grease River shear zone, textures and cathodoluminescence imaging point to dissolution-precipitation creep as the major deformation mechanism for sillimanite, resulting in synkinematic growth of foliation-parallel euhedral sillimanite in a preferred orientation with [001] parallel to the lineation. The results suggest that temperature, fluid content, and modal mineralogy of the surrounding phases may all have significant influence on sillimanite deformation but that preferential alignment of sillimanite [001] parallel to the lineation persists regardless of contrasts in the conditions or mechanisms of deformation.

  9. Radiometric dating of granitic rocks from the Central Bohemian Plutonic Complex (Czech Republic): constraints on the chronology of thermal and tectonic events along the Moldanubian-Barrandian boundary

    NASA Astrophysics Data System (ADS)

    Holub, František V.; Cocherie, Alain; Rossi, Philippe

    1997-07-01

    ingle-zircon dating by step-wise evaporation has established that successive granitic intrusions were emplaced in the Central Bohemian Plutonic Complex (CBPC) during a short time span of about 10 Ma. In agreement with field data, the Požáry trondhjemite, emplaced early at 351 ±11 Ma and subcontemporaneously with the Sázava granodiorite dated at 349 ±12 Ma, was followed by the Blatná granodiorite at 346 ±10 Ma. The magnesium-potassium-rich units (durbachites) indicate younger ages both for the Čertovo Břemeno melagranite at 343 ±6 Ma (within the CPBC) and for durbachite from the Třebíč Massif (south-east of the CPBC) at 340 ±8 Ma. These data provide evidence that the sequence of intrusion and the age of the emplacement of the CBPC are comparable with those of other western Variscan batholiths (i.e. the Vosges or the French Massif Central) in similar structural environment.

  10. Soil mesofauna in disturbed spruce forest stands near Čertovo and Plešné Lakes, the Bohemian Forest: preliminary results

    NASA Astrophysics Data System (ADS)

    Čuchta, Peter; Starý, Jozef

    2016-04-01

    The soil microarthropod communities were studied in disturbed spruce forest stands in the catchments areas of Čertovo (CT) and Plešné (PL) Lakes in the Bohemian Forest, Czech Republic. The study is focused on the impact of the windthrow, bark beetle outbreak damage and consecutive changes in the forest stands including soil environment. Within the soil microarthropods, two main groups, Collembola (Hexapoda) and Oribatida (Acari) are analysed. Four different treatments were selected for the study on both study areas: CT1 and PL1 stands - undamaged control forest stands, CT2 and PL2 stands - "dead" forest stands damaged by bark beetle, CT3 and PL3 stands - slightly managed windthrown forest stands left for the natural succession, and CT4 and PL4 stands - harvested windthrown stands. Soil samples were taken in June (CT1/PL1 - CT3/PL3), July and October (CT1/PL1 - CT4/PL4) 2012 from each treatment. Microarthropods were subsequently extracted in a modified high-gradient apparatus in the laboratory for seven days. Finally, the comparison of the microarthropod assemblages found at different treatment stands was performed. The most abundant groups in both study areas (Čertovo and Plešné Lakes) were Collembola and Oribatida with considerable diferences within particular treatments and in time as well.

  11. Granitic magma emplacement and deformation during early-orogenic syn-convergent transtension: The Staré Sedlo complex, Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Tomek, Filip; Žák, Jiří; Chadima, Martin

    2015-07-01

    The Late Devonian Staré Sedlo complex, Bohemian Massif, was emplaced as a subhorizontal sheeted sill pluton into a transtension zone. The transtensional setting is documented by strong constrictional fabric, corroborated by the anisotropy of magnetic susceptibility (AMS), with variably developed subhorizontal magmatic to solid-state foliation suggesting vertical shortening. Intrusive contacts of the granitoids with metapelitic screens and tapered sill tips indicate that magma wedging was the dominant process of sill propagation. The sills exhibit two intrusive styles, ranging from thin lit-par-lit injections to widely spaced meter-thick sills. These two styles are interpreted as reflecting variable viscosities of intruding magma where low-viscosity magma percolated along foliation planes whereas high-viscosity magma produced more localized thicker sills. We propose that the magma/host rock system in transtension must have evolved from initial crack tip propagation and vertical expansion due to new magma additions through conduit flow to ductile thinning after the magma input had ceased. The sill emplacement and their subsequent deformation are then interpreted as recording early-orogenic syn-convergent sinistral transtension along the rear side of an upper-crustal wedge, which was extruded both upward and laterally in response to subduction and continental underthrusting.

  12. High fluorine pargasites in ultrahigh temperature granulites from Tonagh Island in the Archean Napier Complex, East Antarctica

    NASA Astrophysics Data System (ADS)

    Tsunogae, Toshiaki; Osanai, Yasuhito; Owada, Masaaki; Toyoshima, Tsuyoshi; Hokada, Tomokazu; Crowe, Warwick A.

    2003-09-01

    Pargasites (F/(F+Cl+OH) ratio ( XF) of up to 0.48) from Tonagh Island in Enderby Land, East Antarctica are closely associated with typical high-grade minerals such as orthopyroxene in quartzo-feldspathic, mafic, and ultramafic granulites, and is regarded as a stable mineral at the peak metamorphic conditions (>1100 °C) calculated for the ultrahigh-temperature Archean Napier Complex. Although experimental investigations have suggested that the upper thermal stability limit of F-free pargasite is below 1050 °C, thermodynamic calculations for the present pargasite+quartz assemblage indicate that the thermal stability limit of pargasite with XF=0.5 is about 150 °C higher than that of the hydroxyl end member. Fluorine substitution in the pargasite therefore allowed the mineral to survive the ultrahigh-temperature metamorphism at Tonagh Island. A positive correlation between the F content of pargasite and coexisting biotite indicates that the minerals approach chemical equilibrium in terms of F-OH distribution. Although the fluorine composition of pargasites ( XF=0.12-0.48) and bulk rock (300-2500 ppm) varies widely, the log( fH 2O / fHF) values calculated for these rocks are relatively constant (3.2-3.7), which is consistent with infiltration of an F-bearing fluid during prograde metamorphism. The infiltration of such a fluid is also supported by the higher bulk F content of most of the analyzed samples compared to those of continental and oceanic basaltic rocks, that is, F had been added from an external source. A positive correlation between bulk MgO and F content suggests that F may have been selectively trapped in high- XMg pargasite in MgO-rich rocks.

  13. The Suruli shear zone and regional scale folding pattern in Madurai block of Southern Granulite Terrain, south India

    NASA Astrophysics Data System (ADS)

    Srinivasan, V.; Rajeshdurai, P.

    2010-04-01

    Through the application of remote sensing techniques followed by field checks, the exact extension and nature of Suruli shear zone in Madurai block of southern granulite terrain (SGT) in south India is brought out for the first time in this work. The dominant rock type exposed in this area is charnockite intruded by granites. The Suruli ductile shear zone extends from just west of Kadaiyanallur in the south to Ganguvarpatti in the north over a length of 150 km. Between Kadaiyanallur and Kambam, the shear zone extends roughly in N-S direction. From Kambam, it swerves towards NE and then towards ENE near Ganguvarpatti. The strongly developed transposed foliation and mylonite foliation within the shear zone dip towards east only and so the eastern block (Varushanad hills) is the hanging wall and the western block (Cardamom hills) is the footwall of the shear zone. In the eastern block, three distinct phases of regional scale folding (F1, F2 and F3) are recognized. In complete contrast, the western block recorded only the last phase (F3) regional scale folding. As the more deformed eastern block (older terrain) moved over the relatively less deformed western block (younger terrain) along the Suruli shear zone, it is proposed that this shear zone is a thrust or reverse fault, probably of Proterozoic age. As there are evidences for decreasing displacement from north to south (i.e., from Ganguvarpatti to Kadaiyanallur), the Suruli shear zone could be a rotational thrust or reverse fault with the pivot located close to Kadaiyanallur. As the pivot is located near Achankovil shear zone which trends WNW-ESE (dip towards SSW), the Suruli shear zone could be splaying (branching) out from Achankovil shear zone. In a nutshell, the Suruli shear zone could be a splay, rotational thrust or reverse fault.

  14. Geochemical signatures of metasedimentary rocks of high-pressure granulite facies and their relation with partial melting: Carvalhos Klippe, Southern Brasília Belt, Brazil

    NASA Astrophysics Data System (ADS)

    Cioffi, Caue Rodrigues; Campos Neto, Mario da Costa; da Rocha, Brenda Chung; Moraes, Renato; Henrique-Pinto, Renato

    2012-12-01

    High-grade metasedimentary rocks can preserve geochemical signatures of their sedimentary protolith if significant melt extraction did not occur. Retrograde reaction textures provide the main evidence for trapped melt in the rock fabrics. Carvalhos Klippe rocks in Southern Brasília Orogen, Brazil, present a typical high-pressure granulite assemblage with evidence of mica breakdown partial melting (Ky + Grt + Kfs ± Bt ± Rt). The metamorphic peak temperatures obtained by Zr-in-Rt and ternary feldspar geothermometers are between 850 °C and 900 °C. The GASP baric peak pressure obtained using grossular rich garnet core is 16 kbar. Retrograde reaction textures in which the garnet crystals are partially to totally replaced by Bt + Qtz ± Fsp intergrowths are very common in the Carvalhos Klippe rocks. These reactions are interpreted as a result of interactions between residual phases and trapped melt during the retrograde path. In the present study the geochemical signatures of three groups of Carvalhos Klippe metasedimentary rocks are analysed. Despite the high metamorphic grade these three groups show well-defined geochemical features and their REE patterns are similar to average compositions of post-Archean sedimentary rocks (PAAS, NASC). The high-pressure granulite facies Grt-Bt-Pl gneisses with immature arenite (wacke, arkose or lithic-arenite) geochemical signatures present in the Carvalhos Klippe are compared to similar rocks in amphibolite facies from the same tectonic framework (Andrelândia Nappe System). The similar geochemical signatures between Grt-Bt-Pl gneisses metamorphosed in high-pressure granulite facies and Grt-Bt-Pl-Qtz schists from the Andrelândia and Liberdade Nappes, with minimal to absent melting conditions, are suggestive of low rates of melt extraction in these high-grade rocks. The rocks with pelitic compositions most likely had higher melt extraction and even under such circumstances nevertheless tend to show REE patterns similar to

  15. Metasedimentary rocks of the Angara-Kan granulite-gneiss block (Yenisey Ridge, south-western margin of the Siberian Craton): Provenance characteristics, deposition and age

    NASA Astrophysics Data System (ADS)

    Urmantseva, L. N.; Turkina, O. M.; Larionov, A. N.

    2012-04-01

    The Angara-Kan granulite-gneiss block (Yenisey Ridge) is one of the main basements uplift within the south-western margin of the Siberian Craton. The major part of the Angara-Kan block is composed of Early Precambrian high-grade metamorphic rocks. Metasedimentary association of the Kan granulitic complex is composed of garnet-bearing, garnet-orthopyroxene and orthopyroxene-bearing gneisses, garnet- and orthopyroxene-bearing gneisses with cordierite and sillimanite. Studied paragneisses were formed at the expense of granulite metamorphism of terrigenous rocks, ranging from graywacke to pelitic rock or mudstone. To estimate the time of sedimentation and metamorphism of the terrigenous deposits, the U-Pb zircon dating has been performed using the SHRIMP II ion microprobe. Detrital zircon cores from the biotite-orthopyroxene and high-alumina gneisses yield ages of 2.6-1.94 and 2.4-1.94 Ga, respectively. Together with the age of the magmatic zircons formed during high-grade metamorphism and partial melting (˜1.89 Ga) and metamorphic rims (˜1.87 Ga) it defines the time of sedimentation between 2.0-1.94 and 1.89-1.87 Ga. Detrital zircon ages indicate both Archean and Paleoproterozioc rocks in provenance source, that agrees with the Nd model ages of metasediments ranging in interval 2.4-2.8 Ga. Potential source of the Archean detrital zircons was the exposed basement of the southwestern Siberian Craton, whereas the Paleoproterozoic juvenile crustal source seems to be buried basement of the Tungus province of the Siberian Craton. Deposition of the Kan terrigeneous rocks was coeval with sedimentation in the southeastern part of the Sharyzhalgay uplift, where ages of detrital zircon cores and metamorphic rims from paragneisses bracket sediment deposition between 1.95 and 1.85 Ga.

  16. Thermochronological record of long term faulting, burial and exhumation history in the Sudetes (Bohemian Massif, Central Europe): a multi-system thermochronological approach

    NASA Astrophysics Data System (ADS)

    Štěpančíková, P..; Danišík, M.; Evans, N. J.

    2012-04-01

    Reconstructing erosional and faulting history in the old crystalline basement terrains, with lacking or sparse post-tectonic geological records, is a challenging task where even radiometric data on the basement rocks need not to provide ultimate answers. NE part of the Bohemian Massif (known as the Sudetes) represents a classic example where numerous attempts to constrain denudation, faulting and relief formation on the Variscan basement, often based on incomplete lines of evidence, led to formulation of controversial models. In this study we aim to reconstruct the post-orogenic exhumation history of the Rychlebské hory Mts. in the eastern Sudetes and constrain paleo-activity along the Sudetic Marginal Fault (SMF) - one of the morphologically most prominent, but poorly understood features of Central Europe, forming a >140 km long escarpment separating the Sudetic Mountains from the foreland in the northeast. We do so by applying zircon (U-Th)/He (ZHe), apatite fission track (AFT) and apatite (U-Th)/He (AHe) dating methods to the basement samples from different fault-bounded blocks and sparsely preserved post-orogenic sedimentary samples. New thermochronological data reveals that in the Late Cretaceous at ~95-80 Ma, the Carboniferous-Permian basement blocks SW and NE of the SMF were buried to ~4-7 km and >6.5 km depths, respectively, by sediments of the Bohemian Cretaceous Basin System. This finding contradicts the traditional paleogeographic reconstructions suggesting exposure of large portions of the Sudetes for most of the Mesozoic-Cenozoic. During the burial, the SMF acted as a normal fault as documented by offset in ZHe ages across the fault. At 85-70 Ma, the basin was inverted, Cretaceous strata eroded and basement blocks were exhumed to the near-surface at exhumation rate of ~300 m/Ma as evidenced by Late Cretaceous-Paleocene AFT ages and thermal modelling results. There is no appreciable difference in AFT and AHe ages across the fault suggesting that the

  17. Crustal melting during subduction at mantle depth: anatomy of near-UHP nanogranites (Orlica-Śnieżnik Dome, Bohemian Massif)

    NASA Astrophysics Data System (ADS)

    Ferrero, Silvio; Ziemann, Martin; Walczak, Katarzyna; Wunder, Bernd; O'Brien, Patrick J.; Hecht, Lutz

    2015-04-01

    Small volumes (≤ 50µm) of hydrous melt were trapped as primary inclusions in peritectic garnets during partial melting of metagranitoids from the Orlica-Śnieżnik Dome (Bohemian Massif) at mantle depth [1]. Detailed microstructural/microchemical investigation confirmed the occurrence of a granitic assemblage (biotite+feldspars+quartz) in every investigated inclusion, i.e they are nanogranites [2]. MicroRaman mapping of unexposed inclusions showed the occurrence of residual, H2O-rich glass in interstitial position. Despite the oddity of this finding within a classic regional HP/HT terrain, an incomplete crystallization of the melt inclusions (MI) is consistent with the (relatively) rapid exhumation of the Orlica-Śnieżnik Dome proposed by some authors [e.g. 3]. Moreover glassy and partially crystallized MI have been already reported in lower-P (<1 GPa) migmatites [4]. MicroRaman investigation also showed the possible presence of kumdykolite, a high-temperature polymorph of albite reported in UHP rocks from the Kokchetav Massif as well as the Bohemian massif ([5] and references therein). Experimental re-homogenization of nanogranites was achieved using a piston cylinder apparatus at 2.7 GPa and 875°C under dry conditions, in order to investigate melt composition and H2O content with in situ techniques. The trapped melt is granitic, hydrous (6 wt% H2O) and metaluminous (ASI=1.03), and it is similar to those produced experimentally from crustal lithologies at mantle conditions. Re-homogenization conditions are consistent with the results of geothermobarometric calculations on the host rock, suggesting that no H2O loss occurred during exhumation - this would have caused a shift of the inclusion melting T toward higher values. Coupled with the absence of H2O-loss microstructural evidence, e.g. decrepitation cracks and/or vesciculation [4] in re-homogenized nanogranites, this evidence suggests that the nanogranites still preserves the original H2O content of the

  18. Petrology and mineral equilibrium modeling of incipient charnockite from the Lützow-Holm Complex, East Antarctica: implications for granulite formation in a Gondwana fragment

    NASA Astrophysics Data System (ADS)

    Tsunogae, Toshiaki

    2015-04-01

    Charnockite (orthopyroxene-bearing granitoid) is regarded as one of the fundamental lithologies in many high-grade metamorphic terranes including Neoproterozoic collisional orogen formed during the amalgamation of Gondwana supercontinent. Although both magmatic (massive) and metamorphic charnockites have been reported, several classic examples for the spectacular development of 'incipient charnockites' within orthopyroxene-free felsic gneisses are exposed in several quarry sections in Neoproterozoic granulite terrenes in southern India (e.g., Trivandrum Block) and Sri Lanka. (e.g., Wanni Complex). The charnockite-forming process in these localities is considered to have been triggered by the infiltration of CO2-rich anhydrous fluids along structural pathways within upper amphibolite facies gneisses, resulting in the lowering of water activity and stabilization of orthopyroxene through the breakdown of biotite. However, no detailed study of incipient charnockites in the Lützow-Holm Complex of East Antarctica, which is regarded as an extension of Neoproterozoic to Cambrian orogeny in India and Sri Lanka, has been reported so far. This study thus reports new petrological data of incipient charnockite patches in orthopyroxene-free felsic gneiss from Skallevikshalsen in the granulite-facies region of the Lützow-Holm Complex, East Antarctica, and discuss the timing and process of charnockite formation. Incipient charnockite (Opx + Qtz + Pl + Kfs + Grt) occurs as dark brownish patches of several cm in length within coarse-grained leucocratic gneiss (Qtz + Pl + Kfs + Grt) interlayered with various supracrustal lithologies such as mafic granulite, pelitic granulite, and marble. Orthopyroxene, which occurs only in garnet-bearing portion of the rock, probably formed by a FMAS continuous reaction: Grt + Qtz => Opx + Pl. Phase equilibrium modeling in the system NCKFMASH suggests a wide range of P-T stability (>780 C, >6 kbar), although the condition is broadly consistent with

  19. A seismogenic zone in the deep crust indicated by pseudotachylytes and ultramylonites in granulite-facies rocks of Calabria (Southern Italy)

    NASA Astrophysics Data System (ADS)

    Altenberger, U.; Prosser, G.; Grande, A.; Günter, C.; Langone, A.

    2013-10-01

    Pseudotachylyte veins frequently associated with mylonites and ultramylonites occur within migmatitic paragneisses, metamonzodiorites, as well as felsic and mafic granulites at the base of the section of the Hercynian lower crust exposed in Calabria (Southern Italy). The crustal section is tectonically superposed on lower grade units. Ultramylonites and pseudotachylytes are particularly well developed in migmatitic paragneisses, whereas sparse fault-related pseudotachylytes and thin mylonite/ultramylonite bands occur in granulite-facies rocks. The presence of sillimanite and clinopyroxene in ultramylonites and mylonites indicates that relatively high-temperature conditions preceded the formation of pseudotachylytes. We have analysed pseudotachylytes from different rock types to ascertain their deep crustal origin and to better understand the relationships between brittle and ductile processes during deformation of the deeper crust. Different protoliths were selected to test how lithology controls pseudotachylyte composition and textures. In migmatites and felsic granulites, euhedral or cauliflower-shaped garnets directly crystallized from pseudotachylyte melts of near andesitic composition. This indicates that pseudotachylytes originated at deep crustal conditions (>0.75 GPa). In mafic protoliths, quenched needle-to-feather-shaped high-alumina orthopyroxene occurs in contact with newly crystallized plagioclase. The pyroxene crystallizes in garnet-free and garnet-bearing veins. The simultaneous growth of orthopyroxene and plagioclase as well as almandine, suggests lower crustal origin, with pressures in excess of 0.85 GPa. The existence of melts of different composition in the same vein indicates the stepwise, non-equilibrium conditions of frictional melting. Melt formed and intruded into pre-existing anisotropies. In mafic granulites, brittle faulting is localized in a previously formed thin high-temperature mylonite bands. migmatitic gneisses are deformed into

  20. Coupled mass transfer through a fluid phase and volume preservation during the hydration of granulite: An example from the Bergen Arcs, Norway

    NASA Astrophysics Data System (ADS)

    Centrella, Stephen; Austrheim, Håkon; Putnis, Andrew

    2015-11-01

    The Precambrian granulite facies rocks of Lindås Nappe, Bergen Arcs, Caledonides of W. Norway are partially hydrated at amphibolite and eclogite facies conditions. The Lindås Nappe outcrops over an area of ca. 1000 km2 where relict granulite facies lenses make up only ca. 10%. At Hillandsvatnet, garnetite displays sharp hydration fronts across which the granulite facies assemblage composed of garnet (55%) and clinopyroxene (45%) is replaced by an amphibolite facies mineralogy defined by chlorite, epidote and amphibole. The major element bulk composition does not change significantly across the hydration front, apart from the volatile components (loss on ignition, LOI) that increases from 0.17 wt.% in the granulite to 2.43 wt.% in the amphibolite. However the replacements of garnet and of clinopyroxene are pseudomorphic so that the grain shapes of the garnet and clinopyroxene are preserved even when they are completely replaced. The textural evolution during the replacement of garnet by pargasite, epidote and chlorite and of pyroxene by hornblende and quartz in our rock sample conforms to that expected by a coupled dissolution-precipitation mechanism. SEM and electron microprobe analysis coupled with the software XMapTools V 1.06.1 were used to quantify the local mass transfer required during the replacement processes. The element losses and gains in replacing the garnet are approximately balanced by the opposite gains and losses associated with the replacement of clinopyroxene. The coupling between dissolution and precipitation on both the grain and whole rock spatial scale preserves the volume of the rock throughout the hydration process. However, the hydration involves reduction of rock density and mass balance calculations, together with volume preservation (isovolumetric reaction) require a significant loss of the mass of the rock to the fluid phase. This suggests a mechanism for coupling between the local stress generated by hydration reactions and mass

  1. Magnetic Characteristics of the Lower Crust: Examples from the Chipman Tonalite, Chipman Dikes, and Fehr Granite, Athabasca Granulite Terrane, Northern Canada

    NASA Astrophysics Data System (ADS)

    Brown, L. L.; Koteas, C.; Seaman, S. J.; Williams, M. L.

    2011-12-01

    The Athabasca granulite terrane (AGT) in northernmost Saskatchewan, Canada is an outstanding exposure of lower crustal rocks having experienced high temperature (~800°C) and high pressure (>1.0 GPa) conditions followed by uplift and exhumation to the surface. With little alteration since 1.9 Ga these rocks allow us to study ancient lower crustal lithologies. Aeromagnetic anomalies over this region are distinct and complex, and along with other geophysical measurements, define the Snowbird Tectonic zone, stretching NE-SW across the Canadian Shield and separating the Churchill province into the Hearne domain (mid-crustal rocks, lower metamorphism) from the Rae domain (lower crust rocks, higher metamorphism). The eastern part of the AGT is dominated by the Chipman tonalite batholith (3.3 Ga), and on the far east the Fehr Granite (2.4 Ga). Both units were intruded by the extensive mafic Chipman dike swarm at ~1.9 Ga. On-going magnetic studies of these three units are aimed at characterizing the rock magnetism and remanence of each group as well as relating magnetic properties to the observed aeromagnetic signatures. The Fehr granite is weakly magnetic, with susceptibilities ranging from 9.4 x 10-6 to 2.1 x 10-4 with an average of 9 x 10-5 SI. The remanence held by many Fehr granite samples is weak, but stronger than expected at ~1 mA/m. The bland aeromagnetic signature over the Fehr granite reflects low susceptibility and low remanence. Chipman tonalite samples show a wide range of magnetic properties including distinct oxide zones with susceptibilities of 0.3 SI and remanence values greater than 10 A/m to relatively non-magnetic areas with susceptibilities of 1x 10-4 SI and magnetization of .01 A/m. Hysteresis properties indicate a range of behavior from single-domain to multi-domain magnetite with a majority of samples indicating pseudo-single-domain behavior (average Mr/Ms = 0.13, Hcr/Hc = 3.3). Low temperature experiments confirm the presence of magnetite, and

  2. Variscan granitoids related to shear zones and faults: examples from the Central Sudetes (Bohemian Massif) and the Middle Odra Fault Zone

    NASA Astrophysics Data System (ADS)

    Oberc-Dziedzic, T.; Kryza, R.; Pin, C.

    2015-07-01

    The granitoid intrusions of the Central Sudetes (CS) and of the Middle Odra Fault Zone (MOFZ), NE part of the Bohemian Massif, are both spatially and temporally related to large-scale shear zones and faults (including possible terrane boundaries) that provided effective channels for melt migration. Summarizing common features of the CS and MOFZ granitoids, we have delineated a set of characteristics of the fault-related and shear zone-related granitoids: (1) they are mainly generated by partial melting of crustal sources, with variable contribution (or no contribution) of mantle materials; (2) the sheet-like, steeply inclined, narrow and rather small granitoid intrusions are emplaced within shear zones at mid-crustal level (c. 20 km depth), whereas the larger, flat-lying plutons intrude into the upper crust, outside or above these shear zones; (3) the magmatic foliation and lineation in granitoids of the deeper, sheet-like intrusions are concordant with those in the surrounding metamorphic rocks, suggesting that the solidification of granitoids was coeval with the deformation in the shear zones; instead, the magmatic foliation in the shallower and larger dome-like plutons reflects magma flow; (4) ductile, transcurrent movements along the shear zones postdate medium-pressure regional metamorphism and are accompanied by an increase in the local thermal gradient, as documented by the crystallization of cordierite, andalusite and sillimanite; (5) the increase in the thermal gradient precedes the emplacement of granitoids and their concomitant thermal influence on the country rocks. The granitoids related to the final stages of tectonothermal activity of the shear zones are good-time markers of their evolutionary path.

  3. Two-stage exhumation of subducted Saxothuringian continental crust records underplating in the subduction channel and collisional forced folding (Krkonoše-Jizera Mts., Bohemian Massif)

    NASA Astrophysics Data System (ADS)

    Jeřábek, Petr; Konopásek, Jiří; Žáčková, Eliška

    2016-08-01

    The Krkonoše-Jizera Massif in the northern part of the Variscan Bohemian Massif provides insight into the exhumation mechanisms for subducted continental crust. The studied region exposes a relatively large portion of a flat-lying subduction-related complex that extends approximately 50 km away from the paleosuture. wide extent of HP-LT metamorphism has been confirmed by new P-T estimates indicating temperatures of 400-450 °C at 14-16 kbar and 450-520 °C at 14-18 kbar for the easternmost and westernmost parts of the studied area, respectively. A detailed study of metamorphic assemblages associated with individual deformation fabrics together with analysis of quartz deformation microstructures and textures allowed characterisation of the observed deformation structures in terms of their subduction-exhumation memory. An integration of the lithostratigraphic, metamorphic and structural data documents a subduction of distal and proximal parts of the Saxothuringian passive margin to high-pressure conditions and their subsequent exhumation during two distinct stages. The initial stage of exhumation has an adiabatic character interpreted as the buoyancy driven return of continental material from the subduction channel resulting in underplating and progressive nappe stacking at the base of the Teplá-Barrandian upper plate. With the transition from continental subduction to continental collision during later stages of the convergence, the underplated high-pressure rocks were further exhumed due to shortening in the accretionary wedge. This shortening is associated with the formation of large-scale recumbent forced folds extending across the entire studied area.

  4. Origin of the Zálesí U-Ni-Co-As-Ag/Bi deposit, Bohemian Massif, Czech Republic: fluid inclusion and stable isotope constraints

    NASA Astrophysics Data System (ADS)

    Dolníček, Zdeněk; Fojt, Bohuslav; Prochaska, Walter; Kučera, Jan; Sulovský, Petr

    2009-01-01

    The Zálesí vein-type deposit is hosted by Early Paleozoic high-grade metamorphic rocks on the northern margin of the Bohemian Massif. The mineralization is composed of three main stages: uraninite, arsenide, and sulfide. The mineral assemblages formed at low temperatures (~80 to 130°C, locally even lower) and low pressures (<100 bars). The salinity of the aqueous hydrothermal fluids (0 to 27 wt.% salts) and their chemical composition vary significantly. Early fluids of the oldest uraninite stage contain a small admixture of a clathrate-forming gas, possibly CO2. Salinity correlates with oxygen isotope signature of the fluid and suggests mixing of brines [ δ 18O around +2‰ relative to standard mean ocean water (SMOW)] with meteoric waters ( δ 18O around -4‰ SMOW). The fluid is characterized by highly variable halogen ratios (molar Br/Cl = 0.8 × 10-3 to 5.3 × 10-3; molar I/Cl = 5.7 × 10-6 to 891 × 10-6) indicating a dominantly external origin for the brines, i.e., from evaporated seawater, which mixed with iodine-enriched halite dissolution brine. The cationic composition of these fluids indicates extensive interaction of the initial brines with their country rocks, likely associated with leaching of sulfur, carbon, and metals. The brines possibly originated from Permian-Triassic evaporites in the neighboring Polish Basin, infiltrated into the basement during post-Variscan extension and were finally expelled along faults giving rise to the vein-type mineralization. Cenozoic reactivation by low-salinity, low- δ 18O (around -10‰ SMOW) fluids of mainly meteoric origin resulted in partial replacement of primary uraninite by coffinite-like mineral aggregates.

  5. Petrology, phase equilibria and monazite geochronology of granulite-facies metapelites from deep drill cores in the Ordos Block of the North China Craton

    NASA Astrophysics Data System (ADS)

    He, Xiao-Fang; Santosh, M.; Bockmann, Kiara; Kelsey, David E.; Hand, Martin; Hu, Jianmin; Wan, Yusheng

    2016-10-01

    Among the various Precambrian crustal blocks in the North China Craton (NCC), the geology and evolution of the Ordos Block remain largely enigmatic due to paucity of outcrop. Here we investigate granulite-facies metapelites obtained from deep-penetrating drill holes in the Ordos Block and report petrology, calculated phase equilibria and in-situ monazite LA-ICP-MS geochronology. The rocks we studied are two samples of cordierite-bearing garnet-sillimanite-biotite metapelitic gneisses and one graphite-bearing, two-mica granitic gneiss. The peak metamorphic age from LA-ICP-MS dating of monazite in all three samples is in the range of 1930-1940 Ma. The (U + Pb)-Th chemical ages through EPMA dating reveals that monazite occurring as inclusions in garnet are older than those in the matrix. Calculated metamorphic phase diagrams for the cordierite-bearing metapelite suggest peak P-T conditions ca. 7-9 kbar and 775-825 °C, followed by decompression and evolution along a clockwise P-T path. Our petrologic and age data are consistent with those reported from the Khondalite Belt in the Inner Mongolia Suture Zone in the northern part of the Ordos Block, suggesting that these granulite-facies metasediments represent the largest Paleoproterozoic accretionary belt in the NCC.

  6. Oxygen isotope variations in granulite-grade iron formations: constraints on oxygen diffusion and retrograde isotopic exchange

    USGS Publications Warehouse

    Sharp, Z.D.; O'Neil, J.R.; Essene, E.J.

    1988-01-01

    The oxygen isotope ratios of various minerals were measured in a granulite-grade iron formation in the Wind River Range, Wyoming. Estimates of temperature and pressure for the terrane using well calibrated geothermometers and geobarometers are 730??50?? C and 5.5??0.5 kbar. The mineral constraints on fluid compositions in the iron formation during retrogression require either very CO2-rich fluids or no fluid at all. In the iron formation, isotopic temperature estimates from quartz-magnetite fractionations are controlled by the proximity to the enclosing granitic gneiss, and range from 500?? C (??qz - mt=10.0???) within 2-3 meters of the orthogneiss contact to 600?? C (??qz - mt=8.0???) farther from the contact. Temperature estimates from other isotopic thermometers are in good agreement with those derived from the quartz-magnetite fractionations. During prograde metamorphism, the isotopic composition of the iron formation was lowered by the infiltration of an external fluid. Equilibrium was achieved over tens of meters. Closed-system retrograde exchange is consistent with the nearly constant whole-rock ??18Owr value of 8.0??0.6???. The greater ??qz-mt values in the iron formation near the orthogneiss contact are most likely due to a lower oxygen blocking temperature related to greater exchange-ability of deformed minerals at the contact. Cooling rates required to preserve the quartz-magnetite fractionations in the central portion of the iron formation are unreasonably high (???800?? C/Ma). In order to preserve the 600?? C isotopic temperature, the diffusion coefficient D (for ??-quartz) should be two orders of magnitude lower than the experimentally determined value of 2.5??10-16 cm2/s at 833 K. There are no values for the activation energy (Q) and pre-exponential diffusion coefficient (D0), consistent with the experimentally determined values, that will result in reasonable cooling rates for the Wind River iron formation. The discrepancy between the diffusion

  7. P-T Evolution and Ages of Granulite Facies Rocks from the Winding Stair Gap, Eastern Blue Ridge

    NASA Astrophysics Data System (ADS)

    El-Shazly, A. K.; Loehn, C.

    2007-12-01

    The Winding Stair Gap, NW of Franklin, North Carolina, exposes schists, gneisses, granofelses, stromatic metatexites, and minor diatexites representing mostly pelitic and semipelitic rocks affected by granulite facies conditions. Characteristic mineral assemblages in mesosomes and melanosomes include: garnet (Gt) + biotite (Bt) + sillimanite (Sill) + plagioclase (Plg) + quartz (Qz), Gt+ hornblende (Hb) + Bt + Plg + Qz, and orthopyroxene (Opx) + Bt + Qz. Leucosomes are predominated by Plg + Qz, and contain Gt, kyanite (Ky), Sill, and retrograde muscovite (Musc). Moecher et al. (2004) concluded that these rocks followed a counterclockwise P-T path with peak conditions at 850-900°C, 8-9 kbar. However, the occurrence of relict Ky and staurolite overgrown by Gt and Sill, rutile included in Gt or rimmed by ilmenite, and texturally early Ky in leucosomes relative to intergranular fibrolite, all suggest that these rocks followed a clockwise P-T path in which dehydration melting of muscovite began in the stability field of Ky. Rinds of Plg + Qz + Musc separating Gt from Bt, and Bt inclusions in Opx suggest the onset of dehydration melting of Bt. Calculations using THERMOCALC and compositions of Gt and Bt separated by Qz or Plg (XAn = 0.35) suggest equilibration at 750 to 830°C, 7 to 9 kbar. This was followed by a stage of near isobaric cooling during which K- feldspar back reacted to Musc, and Sill + Bt replaced Gt. Two monazite crystals from a Bt + Gt + Sill + Qz + Plg schist, display patchy zoning for Th, Y, U, and Ca. Statistical analysis of microprobe age profiles across these grains yields three age populations of 353 ± 11 Ma, 450 ± 8 Ma, and 488 ± 8 Ma, with the oldest ages restricted to the grain interiors. A third monazite associated with Sill and Bt truncating Gt is almost homogeneous, and yields ages of ~348 ± 8 Ma. These data suggest that peak T metamorphism and partial melting in the eastern Blue Ridge was Taconic (~450 Ma) during which monazite crystals

  8. Formation of garnet + corundum during isobaric cooling at UHT conditions: an example from pelitic granulites of the Highland Complex, Sri Lanka

    NASA Astrophysics Data System (ADS)

    Laksthitha Dharmapriya, Prasanna; Galli, Andrea; Prabath Malaviarachchi, Sanjeeva; Su, Ben-Xun

    2014-05-01

    Coexisting garnet and corundum have been reported from different rock types such as UHP rocks, aluminous eclogites, kimberlites and numerous granulites worldwide which experienced UHT conditions of 900-1050 °C at relatively high but not eclogitic pressures of 10-12 kbar. In pelitic granulites the assemblage garnet + corundum is usually interpreted to form at peak P during prograde heating along a clock-wise metamorphic path and subsequently breaks down during decompression to form sapphirine, cordierite-sapphirine-spinel or spinel-sillimanite bearing assemblages, depending on the PT-trajectory and bulk rock composition. In any cases, coexisting garnet + corundum are rarely preserved. Even less usual is the occurrence of garnet + corundum in pyroxene-free rocks. In this study, we report the occurrence of coexisting garnet + corundum within spinel- and corundum-bearing, orthopyroxene-free garnet-sillimanite-biotite-graphite gneisses from the Highland Complex (HC), Sri Lanka. In the investigated pelitic granulites, quartz-saturated domains and quartz-deficient domains are distinguishable. Quartz-saturated domains consist of quartz, plagioclase, alkali-feldspar, garnet-porphyroblasts and biotite flakes around garnet. Quartz-deficient domains are constituted of sillimanite, plagioclase, alkali-feldspar, corundum, spinel, biotite and two generations of garnet. Grt1 is coarse- to medium-grained (0.5-3 cm in diameter) and encloses rare Ti-rich biotite and numerous rutile needles and apatite rods. Grt2 is medium- to fine-grained (0.25-1 cm in diameter), contains rare sillimanite and/or spinel inclusions and is always associated with corundum. Corundum occurs in mutual contact with Grt2, partially embedded within rim area of Grt2 or as inclusions in Grt2. Rarely, tiny spinel inclusions can be observed in corundum. The chemistry of minerals preserved as inclusion in Grt1 indicates that pelitic granulites attained maximal P of 10.5-11 kbar at T around 850°C during their

  9. Grain-scale processes in actively deforming magma mushes: New insights from electron backscatter diffraction (EBSD) analysis of biotite schlieren in the Jizera granite, Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Žák, Jiří; Verner, Kryštof; Týcová, Patricie

    2008-12-01

    In the porphyritic Jizera granite, Bohemian Massif, three distinct types of lattice-preferred orientations of biotite grains were revealed in schlieren-delineated magmatic structures using the electron backscatter diffraction (EBSD) method. (1) Biotite basal planes (001) reorient from schlieren-subparallel near the schlieren base to schlieren-perpendicular in the upper part of the schlieren. Both orientations share subhorizontal ˜N-S to ˜NNE-SSW-trending a axes. (2) In some domains, the a axes are steep and at a high angle to the schlieren plane while the c axes plunge shallowly and rotate around an ill-defined a axis. (3) In other domains, the EBSD coincides with background magnetic fabric of the host granite revealed using the anisotropy of magnetic susceptibility (AMS) method: that is, the a axes plunge shallowly to the SE or NW while the c axes are subhorizontal and cluster around the ˜NE-SW trend. These multiple biotite orientations in the schlieren are interpreted to reflect (1) velocity-gradient in laminar magma flow along channel-like conduits, localized within the high-strength host phenocryst framework, (2) grain-scale gravity-driven constrictional deformation of the magma mush, and (3) overprinting background (tectonic?) deformation transmitted across large parts of the magma chamber prior to its final crystallization. The grain-scale mechanisms of biotite fabric acquisition in the schlieren presumably involved rotation of biotite crystals during flow, with the biotite alignment reflecting the flow geometry and kinematics, replaced after flow cessation by melt-aided grain-boundary sliding of those biotite crystals still enclosed in melt pockets within otherwise static, highly crystallized magma mush. The latter process was sufficient to reorient biotite grains but not to cause destruction of the schlieren. Using the Jizera granite as a case example, we argue that the lattice-preferred orientation of mineral grains in mafic schlieren is highly

  10. Structural style, deformation mechanisms and paleodifferential stress along an exposed crustal section: constraints on the rheology of quartzofeldspathic rocks at supra- and infrastructural levels (Bohemian Massif)

    NASA Astrophysics Data System (ADS)

    Zulauf, G.

    2001-03-01

    Investigations of Variscan shortening of quartzofeldspathic rocks have been carried out along an exposed crustal section located in the western part of the Teplá Barrandian unit (Bohemian Massif). The study focuses on determining differential stress, deformation mechanisms and geometry of Cadomian metagreywackes and Cambrian granitoids which show different grade of Variscan Barrovian-type metamorphism ranging from the greenschist-/subgreenschist-facies boundary (semibrittle deformation regime) to the high-grade amphibolite facies. The semibrittle deformation regime ( T=ca. 300°C) is characterized by large-scale thrusting within a folding environment and by similar intensities of cataclasis, diffusive mass transfer, and crystal plasticity of quartz, the latter including low-temperature migration recrystallization. Within Cadomian quartz veins of the greenschist-facies part, dislocation creep of quartz operated at differential stresses ranging from ca. 70 MPa in the lowermost greenschist-facies to ca. 20 MPa in the uppermost greenschist-facies. These values have been derived by paleopiezometry using the grain size of recrystallized quartz. They are interpreted as upper bounds for the bulk stress because of intense diffusive mass transfer within the adjacent metagreywackes. A marking increase in recrystallized grain size of quartz occurs within the lower greenschist-facies, where low-temperature grain boundary migration is replaced by subgrain rotation. Thus, causion is needed when applying the recrystallized grain size paleopiezometer to this crustal level. Pressure solution of quartz and development of discrete crenulation cleavage was common in fine-grained metagreywackes of the lower greenschist-facies, whereas the upper greenschist-facies ( T=ca. 500-570°C) is characterized by increasing intensity of metamorphic reactions, grain coarsening and development of a schistosity. The entire greenschist-facies level forms a suprastructure where viscosity contrasts

  11. Re-Os and Lu-Hf isotopic constraints on the formation and age of mantle pyroxenites from the Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Ackerman, Lukáš; Bizimis, Michael; Haluzová, Eva; Sláma, Jiří; Svojtka, Martin; Hirajima, Takao; Erban, Vojtěch

    2016-07-01

    We report on the Lu-Hf and Re-Os isotope systematics of a well-characterized suite of spinel and garnet pyroxenites from the Gföhl Unit of the Bohemian Massif (Czech Republic, Austria). Lu-Hf mineral isochrons of three pyroxenites yield undistinguishable values in the range of 336-338 Ma. Similarly, the slope of Re-Os regression for most samples yields an age of 327 ± 31 Ma. These values overlap previously reported Sm-Nd ages on pyroxenites, eclogites and associated peridotites from the Gföhl Unit, suggesting contemporaneous evolution of all these HT-HP rocks. The whole-rock Hf isotopic compositions are highly variable with initial εHf values ranging from - 6.4 to + 66. Most samples show a negative correlation between bulk rock Sm/Hf and εHf and, when taking into account other characteristics (e.g., high 87Sr/86Sr), this may be explained by the presence of recycled oceanic sediments in the source of the pyroxenite parental melts. A pyroxenite from Horní Kounice has decoupled Hf-Nd systematics with highly radiogenic initial εHf of + 66 for a given εNd of + 7.8. This decoupling is consistent with the presence of a melt derived from a depleted mantle component with high Lu/Hf. Finally, one sample from Bečváry plots close to the MORB field in Hf-Nd isotope space consistent with its previously proposed origin as metamorphosed oceanic gabbro. Some of the websterites and thin-layered pyroxenites have variable, but high Os concentrations paralleled by low initial γOs. This reflects the interaction of the parental pyroxenitic melts with a depleted peridotite wall rock. In turn, the radiogenic Os isotope compositions observed in most pyroxenite samples is best explained by mixing between unradiogenic Os derived from peridotites and a low-Os sedimentary precursor with highly radiogenic 187Os/188Os. Steep increase of 187Os/188Os at nearly uniform 187Re/188Os found in a few pyroxenites may be connected with the absence of primary sulfides, but the presence of minor

  12. Human impacts of hydrometeorological extremes in the Bohemian-Moravian Highlands derived from documentary sources in the 18th-19th centuries

    NASA Astrophysics Data System (ADS)

    Dolák, Lukáš; Brázdil, Rudolf; Valášek, Hubert

    2014-05-01

    The extent of damage caused by hydrometeorological events or extremes (HME) has risen up in the entire world in the last few years. Especially the floods, flash floods, torrential rains and hailstorms are the most typical and one of the most frequent kind of natural disasters in the central Europe. Catastrophes are a part of human history and people were forced to cope with their consequences (e. g. material damage, economical losses, impacts on agriculture and society or losses of human lives). This paper analyses the human impacts of HME in the Bohemian-Moravian Highlands (central part of the Czech Republic) on the basis of documentary sources from the 18th-19th centuries. The paper presents various negative impacts of natural disasters on lives and property and subsequent inconveniences of Czech peasants. The preserved archival documents of estates or domains became the primary sources of data (e. g. taxation reliefs, damaged records, reports of afflicted farmers, administrative correspondence etc.). Particularly taxation reliefs relate to taxation system in the Czech lands during the 17th-19th centuries allowing to farmers to ask for tax alleviation when their crops were significantly damaged by any HME. These archival documents are a highly valuable source for the study of human impacts of natural disasters. Devastating consequences of these extremes affected individual farmers much more than the aristocracy. Floods caused inundations of farmer's fields, meadows, houses and farm buildings, washed away the arable land with crops, caused losses of cattle, clogged the land with gravel and mud and destroyed roads, bridges or agricultural equipment. Afflicted fields became worthless and it took them many years to become became fertile again. Crop was also damaged by hailstorms, droughts or late/early frosts. All these events led to lack of food and seeds in the following year and it meant the decrease of living standard, misery and poverty of farmers. Acquired

  13. A ˜ 700 Ma Sm Nd garnet whole rock age from the granulite facies Central Kaoko Zone (Namibia): Evidence for a cryptic high-grade polymetamorphic history?

    NASA Astrophysics Data System (ADS)

    Jung, S.; Kröner, A.; Kröner, S.

    2007-09-01

    Continental collision of the Kalahari and the Congo craton in Africa and the Rio de la Plata Craton in South America resulted in a structurally complex Neoproterozoic belt system, the Kaoko-Dom Feliciano-Ribeira belt. It is uncertain whether these three cratons collided more or less simultaneously during one single orogenic event at ˜ 580-550 Ma or whether the belt owe its structural and metamorphic features to several so far poorly constrained events. The Kaoko Belt (NW Nambia), representing the belt system between the southern Congo Craton and the Rio de la Plata Craton, is an ideal object to study these complexities. Within this belt, high-grade meta-igneous and metasedimentary rocks of the sillimanite-K-feldspar zone contain large garnet porphyroblasts that grew at ca. 730 ± 10 °C at 6.7 ± 1.2 kbar during peak metamorphic granulite-facies conditions. A Sm-Nd garnet-whole rock errorchron ( n = 7, MSWD = 6.0) obtained on a siliceous metasediment yielded an unexpected old age of 692 ±14 Ma which is interpreted as an inherited metamorphic age of an older granulite facies event. It is evident that the dated garnets survived the younger high-grade granulite facies metamorphism that occurred between ca. 570 and 520 Ma and preserved their old Sm-Nd isotope systematics implying that the closure temperature for Sm-Nd in garnet is higher than ca. 730 °C in this case. These results imply fast cooling rates at different times during the Pan-African orogeny that prevent isotopic homogenization at sample scale. Moreover, it is suggestive that trace element (REE) diffusion in garnet is considerably slower than major element diffusion. From a regional point of view, it is possible that these specific siliceous metasedimentary rocks may be unrelated to the Pan-African metamorphic evolution of the Kaoko Belt between 570 and 520 Ma and may represent lithological units that belong to so far unrecognized terranes in the Kaoko Belt.

  14. Rare earth geochemistry of Lewisian granulite-facies gneisses, northwest Scotland: Implications for the petrogenesis of the Archaean lower continental crust

    NASA Astrophysics Data System (ADS)

    Weaver, Barry L.; Tarney, John

    1980-12-01

    Rare earth element (REE) data, together with data for major elements and 14 other trace elements, are presented for ultramafic, mafic, intermediate, tonalitic, trondhjemitic, anorthositic and microline gneisses, representative of the range of rock types making up the 2.9-b.y. Lewisian granulite complex of northwest Scotland. The data are used to constrain petrogenetic models for the Archaean lower crust. Ultramafic gneisses have flat REE patterns with 3-5 times chondrite abundance. The more Fe-rich mafic gneisses show slight light-REE enrichment, range up to 40 times chondritic and some have negative Eu anomalies. Intermediate gneisses have more fractionated REE distributions (Ce N/Yb N= 4-25) but with rather constant heavy REE. Tonalitic gneiss REE patterns are also strongly fractionated, show variable heavy-REE depletion and have positive Eu anomalies. REE patterns of trondhjemitic gneisses are very strongly fractionated (Ce N/Yb N up to ˜ 300), show strong heavy-REE depletion and most have marked positive anomalies. Anorthosites and microcline gneisses have similar REE distributions to the trondhjemites in spite of different major element compositions. Modelling of the REE and other trace element patterns of processes such as fractional crystallisation and partial melting suggests that whereas the mafic gneisses can be related by low-pressure fractional crystallisation, the more silicic gneisses can only be related by high-pressure partial melting of a mafic source. Most of the gneisses represent liquid compositions; few can be regarded as cumulates or the residues of partial melting. The computed average Lewisian granulite does have a positive Eu anomaly, but this is imparted by the more fractionated tonalites and trondhjemites and not by the more mafic components of the gneiss complex. Elements such as K, Rb, Cs, Th and U are removed from the lower crust by a fluid (CO 2-rich) not a melt phase during granulite-facies metamorphism. The Archean lower crust is

  15. The Rožná uranium deposit (Bohemian Massif, Czech Republic): shear zone-hosted, late Variscan and post-Variscan hydrothermal mineralization

    NASA Astrophysics Data System (ADS)

    Kříbek, Bohdan; Žák, Karel; Dobeš, Petr; Leichmann, Jaromír; Pudilová, Marta; René, Miloš; Scharm, Bohdan; Scharmová, Marta; Hájek, Antonín; Holeczy, Daniel; Hein, Ulrich F.; Lehmann, Bernd

    2009-01-01

    Three major mineralization events are recorded at the Rožná uranium deposit (total mine production of 23,000 t U, average grade of 0.24% U): (1) pre-uranium quartz-sulfide and carbonate-sulfide mineralization, (2) uranium, and (3) post-uranium quartz-carbonate-sulfide mineralization. (1) K-Ar ages for white mica from wall rock alteration of the pre-uranium mineralization style range from 304.5 ± 5.8 to 307.6 ± 6.0 Ma coinciding with the post-orogenic exhumation of the Moldanubian orogenic root and retrograde-metamorphic equilibration of the high-grade metamorphic host rocks. The fluid inclusion record consists of low-salinity aqueous inclusions, together with H2O-CO2-CH4, CO2-CH4, and pure CH4 inclusions. The fluid inclusion, paragenetic, and isotope data suggest that the pre-uranium mineralization formed from a reduced low-salinity aqueous fluid at temperatures close to 300°C. (2) The uraniferous hydrothermal event is subdivided into the pre-ore, ore, and post-ore substages. K-Ar ages of pre-ore authigenic K-feldspar range from 296.3 ± 7.5 to 281.0 ± 5.4 Ma and coincide with the transcurrent reorganization of crustal blocks of the Bohemian Massif and with Late Stephanian to Early Permian rifting. Massive hematitization, albitization, and desilicification of the pre-ore altered rocks indicate an influx of oxidized basinal fluids to the crystalline rocks of the Moldanubian domain. The wide range of salinities of fluid inclusions is interpreted as a result of the large-scale mixing of basinal brines with meteoric water. The cationic composition of these fluids indicates extensive interaction with crystalline rocks. Chlorite thermometry yielded temperatures of 260°C to 310°C. During this substage, uranium was probably leached from the Moldanubian crystalline rocks. The hydrothermal alteration of the ore substage followed, or partly overlapped in time, the pre-ore substage alteration. K-Ar ages of illite from ore substage alteration range from 277.2 ± 5.5 to

  16. Magmatic Activity and Crustal Melting During Orogenesis: Laser-ablation U-Pb Geochronology of Dike and Leucosome Generations in Granulites of the Gruf Complex, Central Alps

    NASA Astrophysics Data System (ADS)

    Savage, J. A.; Oalmann, J.; Bousquet, R.; Moeller, A.

    2012-12-01

    Magmatic leucosomes and dikes in metamorphic terranes provide an opportunity to correlate accessory phase crystallization ages with the timing of deformation and metamorphic events, as well as larger scale magmatic intrusions. The Gruf Complex consists of upper amphibolite to lower granulite facies migmatitic gneisses and scarce, UHT sapphirine granulites and is bordered by the c. 31 Ma tonalite-granodiorite Bergell Intrusion and the c. 24 Ma Novate S-type leucogranite. Several mineralogically distinct types of leucosomes and dikes have been identified: 1) biotite-bearing leucosomes, which define the main foliation and are commonly folded; 2) hornblende- and biotite-bearing dikes, which are either boudinaged or crosscut the main foliation; 3) pegmatitic muscovite-, garnet-, beryll-bearing dikes, which commonly crosscut all other rock types. These field observations indicate a change in melt composition during and after the regional metamorphic event and its associated deformation. To correlate these melt types with the timing of metamorphism of the Gruf Complex, and the Bergell and Novate intrusions, U-Pb zircon ages were obtained from several dike and leucosome samples. Grains were separated, mounted in epoxy, and imaged by cathodoluminescence prior to U-Pb isotope analysis by LA-ICP-MS. The outermost zircon growth zones were targeted in order to determine the crystallization age of the host magma. All of the analyzed samples contain oscillatory-zoned domains with ages between 250 Ma and 300 Ma. A leucosome sample from within a brecciated metaperidotite enclave in the granulites contains equant, sector-zoned "soccer ball" zircon grains with an age of 32.4±1.0 Ma. Most dike samples contain unzoned or sector-zoned rims or mantles that range from 30-33 Ma. Most of the pegmatitic samples, regardless of their degree of deformation, contain zircon crystals with weakly zoned rims ranging from 24-27 Ma. However, some undeformed pegmatitic samples lack zircon domains

  17. Tectono-metamorphic evolution of a hot orogen during Gondwanaland assembly: a case study from Palni hills metapelite granulite, south India

    NASA Astrophysics Data System (ADS)

    Bhadra, S.; Nasipuri, P.

    2012-04-01

    This study deals with the tectono-metamorphic evolution of Sapphirine-cordierite-bearing metapelite granulite at Perumalmalai, south India, that occurs as enclave within deformed migmatitic enderbite gneiss of Kodaikanal massif, Madurai granulite block (MB), south India. Pre-peak mineral paragenesis is represented by an inclusion assemblage of sillimanite + plagioclase + Ti-rich biotite ±quartz in Al-rich orthopyroxene. Dehydration melting of biotite marked the onset of ultra-high temperature metamorphism (M1A, ~1000 °C, 10 Kbar). Early stage of retrograde metamorphism (M1B) is characterized by the development of type1-symplectite and corona textures. In type1-symplectite an innermost vermicular sapphirine (Spr - XMg: 0.90, Al/Si: 6.17) - cordierite (Crd) symplectite on sillimanite is followed by cordierite (XMg: 0.94) moat. A meso-perthitic layer laced the interface between cordierite moat and orthopyroxene porphyroblast, the latter showing prominent rim-ward decrease in Al2O3 (up to 3 wt%). The cordierite rim at the interface between sillimanite and orthopyroxene characterizes corona texture. Type1-symplectite and corona domains are circumnavigated by Ti-poor biotite (TiO2: ~3.2 wt%) showing shape preferred alignment, and set in a feldspar matrix showing wide compositional range. By implication, leucosome crystallization was possibly prolonged and enhanced by deformation. Type1-symplectite and corona textures were resulted from melt-solid interaction or silica-metasomatism during early stage of retrogression, Opx+Sil = Spr+Crd → Opx+Sil+melt = Crd. The retrograde metamorphism is constrained at 9 kbar and 950°C, implying an early stage of near-isothermal decompression. Late stage retrograde metamorphism (M2) is also characterized by symplectite textures, type2-symplectite, with innermost sapphirine-cordierite symplectite followed by cordierite corona. Sapphirine in type2-symplectite domain (XMg: 0.89; Al/Si: 5.92), which occurs as inclusion in Opx, is

  18. Feldspathic granulite 79215 - Limitations on T-fo2 conditions and time of metamorphism. [temperature-oxygen fugacity relationship in annealed lunar polymict beccia

    NASA Technical Reports Server (NTRS)

    Mcgee, J. J.; Bence, A. E.; Eichhorn, G.; Schaeffer, O. A.

    1978-01-01

    Feldspathic granulite 79215, an annealed polymict breccia which has a bulk composition between anorthositic gabbro and gabbroic anorthosite, contains numerous oxide complexes in the matrix. An Ar-39-Ar-40 stepwise heating experiment gives a well-defined plateau corresponding to an age of 4.03 + or - 0.02 AE. The polmict character of this breccia and the variability of the complexes suggest that they formed as a consequence of reactions between spinel-rich clasts and matrix under the high-T low-P conditions of an ejecta blanket. The duration of annealing is estimated to have been less than 10 million yr; the absence of a KREEP component may indicate an inhomogeneous distribution of this component at the lunar surface at 4.0 AE.

  19. The Cora Lake Shear Zone: Strain Localization in an Ultramylonitic, Deep Crustal Shear Zone, Athabasca Granulite Terrain, Western Churchill Province, Canada

    NASA Astrophysics Data System (ADS)

    Regan, S.; Williams, M. L.; Mahan, K. H.; Orlandini, O. F.; Jercinovic, M. J.; Leslie, S. R.; Holland, M.

    2012-12-01

    Ultramylonitic shear zones typically involve intense strain localization, and when developed over large regions can introduce considerable heterogeneity into the crust. The Cora Lake shear zone (CLsz) displays several 10's to 100's of meters-wide zones of ultramylonite distributed throughout its full 3-5 km mylonitized width. Detailed mapping, petrography, thermobarometry, and in-situ monazite geochronology suggest that it formed during the waning phases of granulite grade metamorphism and deformation, within one of North America's largest exposures of polydeformed lower continental crust. Anastomosing zones of ultramylonite contain recrystallized grain-sizes approaching the micron scale and might appear to suggest lower temperature mylonitization. However, feldspar and even clinopyroxene are dynamically recrystallized, and quantitative thermobarometry of syn-deformational assemblages indicate high P and T conditions ranging from 0.9 -10.6 GPa and 775-850 °C. Even at these high T's, dynamic recovery and recrystallization were extremely limited. Rocks with low modal quartz have extremely small equilibrium volumes. This is likely the result of inefficient diffusion, which is further supported by the unannealed nature of the crystals. Local carbonate veins suggests that H2O poor, CO2 rich conditions may have aided in the preservation of fine grain sizes, and may have inhibited dynamic recovery and recrystallization. The Cora Lake shear zone is interpreted to have been relatively strong and to have hardened during progressive deformation. Garnet is commonly fractured perpendicular to host rock fabric, and statically replaced by both biotite and muscovite. Pseudotachylite, with the same sense of shear, occurs in several ultramylonitized mafic granulites. Thus, cataclasis and frictional melt are interpreted to have been produced in the lower continental crust, not during later reactivation. We suggest that strengthening of rheologically stiffer lithologies led to

  20. Body Hair

    MedlinePlus

    ... girlshealth.gov/ Home Body Puberty Body hair Body hair Even before you get your first period , you ... removing pubic hair Ways to get rid of hair top Removing body hair can cause skin irritation, ...

  1. Petrology and geochemistry of charnockites (felsic ortho-granulites) from the Kerala Khondalite Belt, Southern India: Evidence for intra-crustal melting, magmatic differentiation and episodic crustal growth

    NASA Astrophysics Data System (ADS)

    Ravindra Kumar, G. R.; Sreejith, C.

    2016-10-01

    The Kerala Khondalite Belt (KKB) of the southern India encompasses volumetrically significant magmatic components. Among these, orthopyroxene-bearing, felsic ortho-granulites, popularly known as charnockites in Indian context, constitute an important lithology. In contrast to the well-known phenomena of arrested charnockitization, the geochemical characteristics and petrogenesis of these ortho-granulite suites remain poorly studied, leaving geodynamic models envisaged for the KKB highly conjectural. In this paper, we try to bridge this gap with detailed results on orthopyroxene-bearing, felsic ortho-granulites spread over the entire KKB and propose a new petrogenetic and crustal evolution model. Based on geochemical characteristics, the orthopyroxene-bearing, felsic ortho-granulites (charnockites sensu lato) of KKB are classified into (1) tonalitic (TC), (2) granitic (GC), and (3) augen (AC) suites. Members of the TC follow sodic (characterized by decreasing CaO/Na2O), whereas those of the GC and AC follow calc-alkaline trends of differentiation. Geochemical patterns of the TC resemble those of the Archaean tonalite-trondhjemite-granodiorite (TTG) suites, with slightly magnesian character (average Mg# = 33), moderate LREE (average LaN = 154), low HREE (average YbN = 6) and Y (1-53 ppm; average 11 ppm). The TC is also characterized by positive to slightly negative europium anomalies (Eu/Eu* = 0.7 to 1.67). The GC and AC suites, on the other hand, resemble post-Archaean arc-related granites. The GC displays ferroan nature (average Mg# = 22), low to moderate degrees of REE fractionation (average [La/Yb]N = 34.84), high contents of Y (5-128 ppm; average 68), and low Sr/Y (1-98) ratios. Significant negative Eu anomalies (Eu/Eu* = 0.18-0.91; average 0.50) and low Sr (65-690 ppm) are also noted in the GC. Similar chemical characteristics are shown by the AC, with ferroan nature (average Mg# = 21), low to moderate degrees of REE fractionation (average [La/Yb]N = 26), high

  2. Isobaric heating and cooling path of the lower crust of a Variscan exotic unit: evidences from P -T estimates in NW Iberian metapelitic granulites

    NASA Astrophysics Data System (ADS)

    Alampi, A.; Gomez Barreiro, J.; Alvarez Valero, A.; Castiñeiras, P.

    2012-12-01

    Allochthonous complexes (AC) in NW Iberia consist of a pile of exotic units characterized by distinct tectonothermal evolution and lithological association, and separated from each other by tectonic contacts, either thrust or extensional detachments. In the Órdenes AC, three groups of units are recognized from bottom to top in the pile: Basal, Ophiolitic and Upper units. Upper units comprise an ensemble of arc-related rocks with a lower section that underwent a high-P and high-T (HP-HT) evolution, and an upper section with an intermediate - pressure (IP) evolution. Extensional detachments have been commonly identifying at the boundary between HP-HT and IP Upper units, like the Fornás and Corredoiras detachments. Pelitic granulites from one IP upper unit, the O Pino unit, have been investigated. Petrologic studies reveal an isobaric tectono-metamorphic crustal evolution throughout a multidisciplinary integration of: (i) detailed microstructural analysis; (ii) EMP mineral chemistry; (iii) mass-balance of the key and representative chemical reactions observed in the microstructures and subsequent interpretation of the reaction sequence; (iv) P-T estimates and paths from phase diagram modeling. Results in the NCKFMASHT system describe an isobaric (c. 7 kbar) continuous heating (and later cooling) evolution ranging from c. 620 to 680 C crossing into the melt-bearing stability fields. These achieved anatectic conditions are evidenced by the presence of both leucosomes (quartz, plagioclase and muscovite) and glass inclusions, mainly in local garnet cores through the dehydration/melting reactions of muscovite first and biotite later. Chemically distinct generations of garnet and plagioclase are evident and stoichiometrically balance each other in continuous reactions. They are consistent with the observations of both a garnet overgrowth and large patches of plagioclase which host euhedral, smaller garnets. In the cooling episode, the newly-grown garnet reacted with melt

  3. Zircon U-Pb and trace element zoning characteristics in an anatectic granulite domain: Insights from LASS-ICP-MS depth profiling

    NASA Astrophysics Data System (ADS)

    Marsh, Jeffrey H.; Stockli, Daniel F.

    2015-12-01

    Understanding the geochemical characteristics of metamorphic zircon, and how they may be modified by recrystallization processes, is fundamental to defining the timescales of tectonic processes affecting continental lithosphere. We utilize laser ablation split-stream (LASS)-ICP-MS depth-profiling analysis to obtain a continuous rim-to-core record of the U-Pb ages and trace-element composition preserved within variably recrystallized zircon from different rock types within a well-studied granulite domain in the western Grenville Province, Canada. Detailed analysis of the depth-resolved signal enables definition of chemically distinct (homogeneous) internal domains and heterogeneous intervening zones that can generally be correlated with textural features observed in CL. Three age populations have been distinguished within the ~ 35 μm deep profiles that correlate well with the established timing of protolith formation, granulite-facies metamorphism, and amphibolite-facies shearing, respectively. The U-Pb isotopic system and Th/U ratios in much of the crystal interiors have undergone considerable modification, as evidenced by a linear correlation between 207Pb/206Pb age and Th/U ratio. Interior and rim domains commonly contain blurred or faded oscillatory zoning patterns, suggesting that solid-state recrystallization is at least partially responsible for the modified U-Th-Pb composition. A number of systematic trends in trace element composition are also observed between interior domains and recrystallized rims, including 1) decreased Th/U (to ~ 0.1), 2) tighter clustering of Hf concentrations, 3) decreased total REE, 4) unchanged Eu anomalies, and 5) a widened spread of HREE enrichment values (YbN/GdN). Both YbN/GdN vs. Th/U and U/Ce vs. Th plots show increasing degree of compositional differentiation from protolith zircon as a function of metamorphic reworking processes (i.e. sample type). The transition zones between interior and rim domains exhibit textural

  4. Mineralogical and textural evidences of melt transfer in a granulite from the Paleoproterozoic Itabuna-Salvador-Curaça belt (Salvador da Bahia, Brazil)

    NASA Astrophysics Data System (ADS)

    Goncalves, Philippe; Santos de Souza, Jailma; Barbosa, Johildo; Bourque, Hugo; Floess, David

    2014-05-01

    In pelitic rocks, the effect of melt transfer (loss and/or gain) on phase relations can be successfully predicted via phase equilibrium modeling and more particularly using pseudosections with bulk composition as a variable (e.g. White et al., 2001). One of the most obvious effect of melt loss is the dehydration of the rock that limits further melting and favors the preservation of peak metamorphic assemblage. However, in most cases, melt loss has a limited effect that can be hardly seen mineralogically. Indeed, composition of phases like garnet, cordierite or plagioclase, that are first-order metamorphic phase, will not be affected significantly by melt loss. Therefore, evidences of melt extraction must be evidenced texturally. The goal of this contribution is to present an example where both mineralogical and textural evidences of melt extraction have been inferred. The studied sample is a pelitic granulite from the Paleoproterozoic Itabuna-Salvador-Curaça belt (Salvador da Bahia, Brazil). It is located in the city of Salvador da Bahia, next to the Farol da Bara. Structurally, it is located in a steeply deeping high strain zone that could have play a major role on the segregation and transfer of melt. The gneissic foliation is marked by a compositional banding with centimer-wide quartzo-feldspathic leucosomes in a garnet-bearing granulite. Leucosomes are almost systematically surrounded by a darker layer that is quartz-undersaturated and enriched in spinel and primatic sillimanite. This silica undersaturation is interpreted as the effect of extreme melt extraction and was modeled using phase diagram section. An interesting feature of the rock is that garnet grain size decreases and the number of garnet grains increases in the melanosome away from the leucosome. Furthermore, the type, amount and shape of inclusions in garnet, chemical composition and zoning in garnet also varies greatly and continuously across the gneissic foliation. Texturally, the presence of

  5. Late Paleozoic tectono-metamorphic evolution of the Altai segment of the Central Asian Orogenic Belt: Constraints from metamorphic P-T pseudosection and zircon U-Pb dating of ultra-high-temperature granulite

    NASA Astrophysics Data System (ADS)

    Li, Zilong; Yang, Xiaoqiang; Li, Yinqi; Santosh, M.; Chen, Hanlin; Xiao, Wenjiao

    2014-09-01

    Ultra-high-temperature (UHT) granulite-facies rocks offer important constraints on crustal evolution processes and tectonic history of orogens. UHT granulites are generally rare in Phanerozoic orogens. In this study, we investigate the late Paleozoic pelitic UHT granulites from Altai in the western segment of the Central Asian Orogenic Belt (CAOB). The diagnostic minerals in these rocks include high alumina orthopyroxene (Al2O3 up to 9.76 wt.%, and y(opx) = AlVI in orthopyroxene up to 0.21) coexisting with sillimanite and quartz, and low Zn spinel (ZnO = 1.85-2.50 wt.%) overgrowth with quartz. Cordierite corona separates sillimanite from orthopyroxene. The high alumina orthopyroxene is replaced by symplectites of low-alumina orthopyroxene (~ 5.80 wt.% Al2O3) and cordierite. These textural observations are consistent with a significant decompression following the peak UHT metamorphism. Phase equilibrium modeling using pseudosections and the y(opx) isopleths indicate an anti-clockwise P-T path for the exhumation of the Altai orogenic belt. The pre-peak assemblage of spinel + quartz in garnet is stable at high- to ultra-high-temperature and low-pressure conditions (P < 5.8 kbar at T ~ 900 °C). The peak P-T values recorded by high aluminium orthopyroxene is > 940 °C and 7.8 to 10 kbar. Subsequent near-isothermal decompression occurred at 890 to 940 °C and 5 to 6 kbar. The final-stage cooling is recorded at 750 and 800 °C and 4 to 5 kbar accompanied by a decrease in the y(opx) values (0.11-0.12). In the UHT granulite, zircon grains are commonly enclosed within cordierite. The overgrowth rims of the zircon grains yield a weighted mean 206Pb/238U age of 277 ± 2 Ma using LA-ICP-MS zircon dating, which is interpreted to mark the timing of decompression and cooling. We propose that the anti-clockwise P-T path of the UHT granulite in the Altai orogenic belt could be related to an extensional event related to the sinistral strike-slip along the Irtish tectonic belt after

  6. CT -- Body

    MedlinePlus

    ... News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Body Computed tomography (CT) of the body uses special x-ray ... Body? What is CT Scanning of the Body? Computed tomography, more commonly known as a CT or CAT ...

  7. Body Composition.

    ERIC Educational Resources Information Center

    Mayhew, Jerry L.

    1981-01-01

    Body composition refers to the types and amounts of tissues which make up the body. The most acceptable method for assessing body composition is underwater weighing. A subcutaneous skinfold provides a quantitative measurement of fat below the skin. The skinfold technique permits a valid estimate of the body's total fat content. (JN)

  8. Scapolite phase equilibria and carbon isotope variations in high grade rocks: Tests of the CO sub 2 -flooding hypothesis of granulite gneiss

    SciTech Connect

    Moecher, D.P.

    1988-01-01

    Scapolite decarbonation reactions and carbon isotope analysis of CO{sub 2} extracted from scapolite are used to determine the presence, composition, and source of fluid components in high grade rocks. Scapolite-plagioclase-garnet-quartz assemblages, common to many lithologies in high grade terranes, monitors CO{sub 2} activity (aCO{sub 2}) by the reaction 2 Meionite + Quarts = 5 Anorthite + Grossular + 2 CO{sub 2}. The P-T-X location of this reaction was calculated using an internally consistent thermodynamic data set for meionite and phases in the CASCH system. Activity-composition relations for meionite in scapolite were calculated from the thermodynamic data set and compositional data on natural scapolite-plagioclase-calcite assemblages. Equilibration pressures of scapolite assemblages were calculated from clinopyroxene-garnet-plagioclass-quartz barometers calibrated for this study. The aCO{sub 2} was calculated for a variety of high grade gneisses from the southwestern Grenville Province and other terranes. Granulites typically yield low to moderate values of aCO{sub 2} (less than 0.5). Calc-silicates and meta-anorthosite yield moderate aCO{sub 2}. Deep crustal xenoliths yield a range of aCO{sub 2}.

  9. LA-MC-ICPMS Pb Pb dating of rutile from slowly cooled granulites: Confirmation of the high closure temperature for Pb diffusion in rutile

    NASA Astrophysics Data System (ADS)

    Vry, Julie K.; Baker, Joel A.

    2006-04-01

    Rapid Pb-Pb dating of natural rutile crystals by laser ablation multiple-collector inductively coupled plasma mass spectrometry (LA-MC-ICPMS) is investigated as a tool for constraining geological temperature-time histories. LA-MC-ICPMS was used to analyse Pb isotopes in rutile from granulite-facies rocks from the Reynolds Range, Northern Territory, Australia. The resultant ages were compared with previous U-Pb zircon and monazite age determinations and new mica (muscovite, phlogopite, and biotite) Rb-Sr ages from the same metamorphic terrane. Rutile crystals ranging in size from 3.5 to 0.05 mm with ⩽20 ppm Pb were ablated with a 300-25 μm diameter laser beam. Crystals larger than 0.5 mm yielded sufficiently precise 206Pb/ 204Pb and 207Pb/ 204Pb ratios to correct for the presence of common Pb, and individual rutile crystals often exhibited sufficient Pb isotopic heterogeneity to allow isochron calculations to be performed on replicate analyses of a single crystal. The mean of 12 isochron ages is 1544 ± 8 Ma (2 SD), with isochron ages for single crystals having uncertainties as low as ±1.3 Myr (2 SD). The 207Pb- 206Pb ages calculated without correction for common Pb are typically <0.5% higher than the common-Pb-corrected isochron ages reflecting the very minor amounts of common Pb present in the rutile. The LA-MC-ICPMS method described samples only the outer 0.1-0.2 mm of the rutile crystals, resulting in a grain size-independent apparent closure temperature ( Tc) for Pb diffusion in rutile that is less than the Tc of monazite ⩽0.1 mm in diameter, but significantly higher than the Rb-Sr system in muscovite (550 °C), phlogopite (435 °C) and biotite (400 °C). Even small rutile crystals are extremely resistant to isotopic resetting. For the established slow cooling rate of ca. 3 °C/Myr, the Tc for Pb diffusion in the analysed rutile is ca. 630 °C. This is in excellent agreement with recent experimental results that indicate that rutile has a higher Tc than

  10. LASS U-Th-Pb monazite and rutile geochronology of felsic high-pressure granulites (Rhodope, N Greece): Effects of fluid, deformation and metamorphic reactions in local subsystems

    NASA Astrophysics Data System (ADS)

    Wawrzenitz, Nicole; Krohe, Alexander; Baziotis, Ioannis; Mposkos, Evripidis; Kylander-Clark, Andrew R. C.; Romer, Rolf L.

    2015-09-01

    The specific chemical composition of monazite in shear zones is controlled by the syndeformation dissolution-precipitation reactions of the rock-forming minerals. This relation can be used for dating deformation, even when microfabric characteristics like shape preferred orientation or intracrystalline deformation of monazite itself are missing. Monazite contemporaneously formed in and around the shear zones may have different compositions. These depend on the local chemical context rather than reflecting successive crystallization episodes of monazite. This is demonstrated in polymetamorphic, mylonitic high-pressure (HP) garnet-kyanite granulites of the Alpine Sidironero Complex (Rhodope UHP terrain, Northern Greece). The studied mylonitic rocks escaped from regional migmatization at 40-36 Ma and from subsequent shearing through cooling until 36 Ma. In-situ laser-ablation split-stream inductively-coupled plasma mass spectrometry (LASS) analyses have been carried out on monazite from micro-scale shear zones, from pre-mylonitic microlithons as well as of monazite inclusions in relictic minerals complimented by U-Pb data on rutile and Rb-Sr data of biotite. Two major metamorphic episodes, Mesozoic and Cenozoic, are constrained. Chemical compositions, isotopic characteristics and apparent ages systematically vary among monazite of four different microfabric domains (I-IV). Within three pre-mylonitic domains (inclusions in (I) pre-mylonitic kyanite and (II) garnet porphyroclasts, and (III) in pre-mylonitic microlithons) monazite yields ages of ca. 130-150 Ma for HP-granulite metamorphism, in line with previous geochronological results in the area. Patchy alteration of the pre-mylonitic monazite by intra-grain dissolution-precipitation processes variably increased negative Eu anomaly and reduced the HREE contents. The apparent age of this altered monazite is reduced. Monazite in the syn-mylonitic shear bands (IV) differs in chemical composition from unaltered and

  11. Anomalous Seismic Velocity Drop in Iron and Biotite Rich Amphibolite to Granulite Facies Transitional Rocks from Deccan Volcanic Covered 1993 Killari Earthquake Region, Maharashtra (India): a Case Study

    NASA Astrophysics Data System (ADS)

    Pandey, O. P.; Tripathi, Priyanka; Vedanti, Nimisha; Srinivasa Sarma, D.

    2016-07-01

    65 Ma Deccan Volcanic Province of western India forms one of the largest flood basaltic eruptions on the surface of the earth. The nature of the concealed crust below this earthquake prone region, which is marked by several low velocity zones at different depths has hardly been understood. These low velocity zones have been invariably interpreted as fluid-filled zones, genetically connected to earthquake nucleation. While carrying out detailed geological and petrophysical studies on the Late Archean basement cores, obtained from a 617 m deep KLR-1 borehole, drilled in the epicentral zone of 1993 Killari earthquake region of the southern Deccan Volcanic Province, we came across several instances where we observed remarkable drop in measured P-wave velocity in a number of high density cores. We provide detailed petrographic and geological data on 11 such anomalous samples which belong to mid-crustal amphibolite to granulite facies transitional rocks. They are associated with a mean P-wave velocity of 6.02 km/s (range 5.82-6.22 km/s) conforming to granitic upper crust, but in contrast have a high mean density of 2.91 g/cm3 (range 2.75-3.08 g/cm3), which characterise mid to lower crust. This velocity drop, which is as much as 15 % in some cores, is primarily attributed to FeOT enrichment (up to about 23 wt%) during the course of mantle-fluid driven retrogressive metasomatic reactions, caused by exhumation of deep-seated mafic rocks. Presence of Iron content (mainly magnetite), widely seen as opaques in thin sections of the rocks, seems to have resulted into sharp increase in density, as well as mean atomic weight. Our study indicates that the measured V p is inversely related to FeOT content as well as mean atomic weight of the rock.

  12. Body Piercing

    PubMed Central

    Koenig, Laura M; Carnes, Molly

    1999-01-01

    OBJECTIVE To review the current information on medical complications, psychological implications, and legislative issues related to body piercing, a largely unregulated industry in the United States. METHODS We conducted a MEDLINE search of English language articles from 1966 until May 1998 using the search terms “body piercing” and “ear piercing.” Bibliographies of these references were reviewed for additional citations. We also conducted an Internet search for “body piercing” on the World Wide Web. MAIN RESULTS: In this manuscript, we review the available body piercing literature. We conclude that body piercing is an increasingly common practice in the United States, that this practice carries substantial risk of morbidity, and that most body piercing in the United States is being performed by unlicensed, unregulated individuals. Primary care physicians are seeing growing numbers of patients with body pierces. Practitioners must be able to recognize, treat, and counsel patients on body piercing complications and be alert to associated psychological conditions in patients who undergo body piercing. PMID:10354260

  13. Durbachites from the Eastern Moldanubicum (Bohemian Massif): erosional relics of large, flat tabular intrusions of ultrapotassic melts—geophysical and petrological record

    NASA Astrophysics Data System (ADS)

    Leichmann, J.; Gnojek, I.; Novák, M.; Sedlák, J.; Houzar, S.

    2016-01-01

    The results of the airborne survey comprising gamma-ray spectrometry and proton magnetometry, ground gravity survey, and field geological observations (e.g., deep borehole profiles, contact aureole in dolomite marbles, distribution of granitic pegmatites within the Třebíč pluton) suggest that the ultrapotassic Třebíč and Jihlava plutons are flat intrusions. They intruded distinct deep levels of the crust, 2-4 kbar for Třebíč pluton, and 5-7 kbar for Jihlava-pluton. Current thickness of the intrusions is generally less than 2 km, with two exceptions: (1) central part of the Jihlava pluton and (2) a small body near Věžnice, where the estimated depth of tube-shaped stocks of shoshonitic and ultrapotassic gabbros or monzogabbros is around 2.5 km. These stocks could represent feeding pipes of basic and alkaline and dry magmas protruding to the upper crust level. The NE part of the Třebíč pluton is a bottom part of this body, whereas the NW corner and the southern promontory of the pluton could represent an upper (roof) part of the intrusion. Small isolated durbachite bodies located within the Moldanubian gneisses and migmatites of the Strážek Unit represent rootless remnants of a former large and flat durbachite body initially extending significantly more to N and NE and eroded since Lower Carboniferous. Discrepancy between the long-wave magnetic and gravity anomalies, and surface geological structure of the eastern part of the Moldanubian Zone indicates a crucial role of the thrust tectonics.

  14. Body Basics

    MedlinePlus

    ... more about how the body works, what basic human anatomy is, and what happens when parts of the body don't function properly. Blood Bones, Muscles, and Joints Brain and Nervous System Digestive System Endocrine System Eyes Female Reproductive System ...

  15. Monitoring and validating the temporal dynamics of interday streamflow from two upland head micro-watersheds with different vegetative conditions during dry periods of the growing season in the Bohemian Massif, Czech Republic.

    PubMed

    Deutscher, Jan; Kupec, Petr

    2014-06-01

    At present, dynamic land use, climate change, and growing needs for fresh water are increasing the demand on the ecosystem effects of forest vegetation. Mountainous areas are at the forefront of scientific interest in European forest ecology and forest hydrology. Although uplands cover a significant area of the Czech Republic and other countries and are often covered with forest formations, they do not receive an appropriate amount of attention. Therefore, two experimental upland head micro-watersheds in the Bohemian Massif were selected for study because they display similar natural conditions, but different vegetative conditions (forest versus meadow). During the 2011 growing season, short-term streamflow measurements were carried out at the discharge profiles of both catchments and were evaluated in relation to climatic data (rainfall and temperature). The basic premise was that the streamflow in a forested catchment must exhibit different temporal dynamics compared to that in treeless areas and that these differences can be attributed to the effects of woody vegetation. These conclusions were drawn from measurements performed during dry periods lasting several days. A decreasing streamflow trend during the day part of the day (0900-1900 hours) was observed in both localities. The decrease reached approx. 44 % of the initial morning streamflow (0.24 dm(3) s(-1) day(-1)) in the treeless catchment and approx. 20 % (0.19 dm(3) s(-1) day(-1)) in the forested catchment. At night (1900-0900 hours), the streamflow in the forested catchment increased back to its initial level, whereas the streamflow in the treeless catchment stagnated or slowly decreased. We attribute these differences to the ecosystem effects of woody vegetation and its capacity to control water loss during the day. This type of vegetation can also function as a water source for the hydrographic network during the night.

  16. Strain partitioning into dry and wet zones and the formation of Ca-rich myrmekite in syntectonic syenites: A case for melt-assisted dissolution-replacement creep under granulite facies conditions

    NASA Astrophysics Data System (ADS)

    De Toni, G. B.; Bitencourt, M. F.; Nardi, L. V. S.

    2016-10-01

    The formation of Ca-rich myrmekites is described in syntectonic syenites crystallized and progressively deformed under granulite facies conditions. The syenites are found in high- and low-strain zones where microstructure and mineral composition are compared. Heterogeneously distributed water-rich, late-magmatic liquids were responsible for strain partitioning into dry and wet high-strain zones at outcrop scale, where contrasting deformation mechanisms are reported. In dry high-strain zones K-feldspar and clinopyroxene are recrystallized under high-T conditions. In wet high-strain zones, the de-stabilization of clinopyroxene and pervasive replacement of relatively undeformed K-feldspar porphyroclasts by myrmekite and subordinate micrographic intergrowths indicate dissolution-replacement creep as the main deformation mechanism. The reworking of these intergrowths is observed and is considered to contribute significantly to the development of the mylonitic foliation and banding. A model is proposed for strain partitioning relating a positive feedback between myrmekite-forming reaction, continuous inflow of late-magmatic liquids and dissolution-replacement creep in the wet zone at the expenses of original mineralogy preserved in the dry zones. Melt-assisted dissolution-replacement creep in syntectonic environments under granulite-facies conditions may extend the field of operation of dissolution-replacement creep, changing significantly the rheology of the lower continental crust.

  17. Granodiorites of the South Mountain Batholith (Nova Scotia, Canada) derived by partial melting of Avalonia granulite rocks beneath the Meguma terrane: Implications for the heat source of the Late Devonian granites of the Northern Appalachians

    NASA Astrophysics Data System (ADS)

    Shellnutt, J. Gregory; Dostal, Jaroslav

    2015-08-01

    The Late Devonian South Mountain Batholith (SMB) of Nova Scotia is the largest batholith of the northern Appalachians. The peraluminous granitic rocks range from biotite granodiorite to leucogranite. Samples collected from a drill core of the Scrag Lake granodioritic pluton of the western SMB are chemically homogeneous from the surface to a depth of ~ 1425 m. The homogeneous composition implies that the granodiorite was derived from a relatively homogeneous source and that country rock assimilation was not an important source for the parental magma. Equilibrium partial melt modeling of underlying sub-Meguma granulite rocks indicates that they are the primary source rocks of the granodiorites. We suggest that mantle-derived magmas intruded the lower crust and induce large-scale melting of the granulite basement rocks to produce the granodiorites. Fractional crystallization of the granodiorites plus assimilation of Meguma Supergroup metasediments likely produces the silica-rich rocks of the SMB. The cause of mantle melting is uncertain however it may be related to the transitioning of the northern Appalachians from a position above the deep mantle Pacific large low shear velocity province (LLSVP) to a higher shear velocity region of the mantle.

  18. Geochemistry and geochronology of the Mkhondo suite, Swaziland: evidence for passive-margin deposition and granulite facies metamorphism in the Late Archean of Southern Africa

    NASA Astrophysics Data System (ADS)

    Condie, K. C.; Kröner, A.; Milisenda, C. C.

    1996-05-01

    The Archean Mkhondo suite in southern Swaziland is a multiply deformed succession of metasediments intruded with amphibolite dykes and sills and granitoid gneisses. Mineral and textural relationships indicate an early period of granulite facies metamorphism, followed later by amphibolite facies metamorphism. Geothermobarometry indicates maximum temperatures of 700-900°C and burial depths of 25-3 km. Paragneisses and biotite quartzites have LREE enriched patterns with small negative Eu anomalies, whereas white quartzites show variable REE patterns and low REE concentrations. BIF has slight LREE enrichment and Eu anomalies. Amphibolites have moderate LREE enrichment and depletions in TaNb and P. Unlike many Archean granitoids, the Mkhondo granitoid gneisses are high in K and other LILE, have large negative Eu anomalies and are not depleted in HREE. SHRIMP {U}/{Pb} isotopic analyses of detrital zircons from a biotite quartzite define a source age of ˜3600-3460 Ma. A deformed granitoid in tectonic contact with the Mkhondo suite yields a zircon evaporation {207Pb}/{206Pb} mean age of 3192±5 Ma, which is interpreted as the age of emplacement. A zircon evaporation age of a granitic melt patch in paragneiss, as well as whole-rock and garnet SmNd isotopic ages, suggest that the peak of high-grade metamorphism in the Mkhondo suite occurred at about 2750 Ma. This is the first evidence for Late Archean high-grade metamorphism in the southeastern Kaapvaal craton. The age data of this study restrict deposition of the Mkhondo suite to between ˜3.2 and ˜2.75 Ga. Mkhondo paragneisses are interpreted as shales with biotite quartzites as iron- and quartz-rich detrital sediments. Geochemical mixing calculations indicate that the sediment sources were composed of basalt (±komatiite), TTG and Eu-depleted granitoids. The Mkhondo assemblage may have been deposited along a passive continental margin or in a continental interior basin. The presence of minor BIF with positive Eu

  19. Body lice

    MedlinePlus

    ... off the body. Your provider may prescribe a skin cream or a wash that contains permethrin, malathione, or benzyl alcohol. If your case is severe, the provider may prescribe medicine that you take by mouth.

  20. Body Image

    MedlinePlus

    ... spider veins Body dysmorphic disorder (BDD) Eating disorders Anorexia nervosa Binge eating disorder Bulimia nervosa Over-exercising ... conditions? Visit our Mental health section. Fact sheets Anorexia nervosa Binge eating disorder Bulimia nervosa Cosmetics and ...

  1. Bog bodies.

    PubMed

    Lynnerup, Niels

    2015-06-01

    In northern Europe during the Iron Age, many corpses were deposited in bogs. The cold, wet and anaerobic environment leads in many cases to the preservation of soft tissues, so that the bodies, when found and excavated several thousand years later, are remarkably intact. Since the 19th century the bog bodies have been studied using medical and natural scientific methods, and recently many bog bodies have been re-examined using especially modern, medical imaging techniques. Because of the preservation of soft tissue, especially the skin, it has been possible to determine lesions and trauma. Conversely, the preservation of bones is less good, as the mineral component has been leached out by the acidic bog. Together with water-logging of collagenous tissue, this means that if the bog body is simply left to dry out when found, as was the case pre-19th century, the bones may literally warp and shrink, leading to potential pitfalls in paleopathological diagnostics. Bog bodies have in several instances been crucial in determining the last meal, as gut contents may be preserved, and thus augment our knowledge on pre-historic diet by adding to, for example, stable isotope analyses. This article presents an overview of our knowledge about the taphomic processes as well as the methods used in bog body research. PMID:25998635

  2. Body Imaging

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The high-tech art of digital signal processing (DSP) was pioneered at NASA's Jet Propulsion Laboratory (JPL) in the mid-1960s for use in the Apollo Lunar Landing Program. Designed to computer enhance pictures of the Moon, this technology became the basis for the Landsat Earth resources satellites and subsequently has been incorporated into a broad range of Earthbound medical and diagnostic tools. DSP is employed in advanced body imaging techniques including Computer-Aided Tomography, also known as CT and CATScan, and Magnetic Resonance Imaging (MRI). CT images are collected by irradiating a thin slice of the body with a fan-shaped x-ray beam from a number of directions around the body's perimeter. A tomographic (slice-like) picture is reconstructed from these multiple views by a computer. MRI employs a magnetic field and radio waves, rather than x-rays, to create images.

  3. Body Imaging

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The high-tech art of digital signal processing (DSP) was pioneered at NASA's Jet Propulsion Laboratory (JPL) in the mid-1960s for use in the Apollo Lunar Landing Program. Designed to computer enhance pictures of the Moon, this technology became the basis for the Landsat Earth resources satellites and subsequently has been incorporated into a broad range of Earthbound medical and diagnostic tools. DSP is employed in advanced body imaging techniques including Computer-Aided Tomography, also known as CT and CATScan, and Magnetic Resonance Imaging (MRI). CT images are collected by irradiating a thin slice of the body with a fan-shaped x-ray beam from a number of directions around the body's perimeter. A tomographic (slice-like) picture is reconstructed from these multiple views by a computer. MRI employs a magnetic field and radio waves, rather than x-rays, to create images. In this photograph, a patient undergoes an open MRI.

  4. Body Imaging

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Magnetic Resonance Imaging (MRI) and Computer-aided Tomography (CT) images are often complementary. In most cases, MRI is good for viewing soft tissue but not bone, while CT images are good for bone but not always good for soft tissue discrimination. Physicians and engineers in the Department of Radiology at the University of Michigan Hospitals are developing a technique for combining the best features of MRI and CT scans to increase the accuracy of discriminating one type of body tissue from another. One of their research tools is a computer program called HICAP. The program can be used to distinguish between healthy and diseased tissue in body images.

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  6. Transition from island-arc to passive setting on the continental margin of Gondwana: U Pb zircon dating of Neoproterozoic metaconglomerates from the SE margin of the Teplá Barrandian Unit, Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Sláma, Jiří; Dunkley, Daniel J.; Kachlík, Václav; Kusiak, Monika A.

    2008-12-01

    Sedimentological, petrological and geochemical data combined with SHRIMP and LA ICP-MS U-Pb ages of pebbles of granitic rocks and detrital zircons from Neoproterozoic Vletice metaconglomerates of the SE margin of the Teplá-Barrandian Unit were used to characterize the regional geotectonic setting at the Proterozoic/Paleozoic boundary. The metaconglomerates form several-metres thick intercalations in metasediments of the Svrchnice Formation (roof pendants of Central Bohemian Plutonic Complex), which is considered to have been deposited in Neoproterozoic/Cambrian times. A sedimentological study indicates that the metaconglomerates are products of debris flows deposited in submarine canyons or proximal parts of submarine fans. Geochemistry of metaconglomerate matrix and petrography of pebbles revealed an obvious difference from the western and central part of the Teplá-Barrandian Unit Proterozoic where pebbles eroded from uplifted parts of the basin and island arc sources are most common. The abundance of quartz, quartzite, granite and crystalline limestone in pebbles together with the more mature composition of host metagreywackes indicate the presence of relatively evolved continental crust in the source area for the Vletice metaconglomerates, and shallowing of the Neoproterozoic basin to the SE (in the present geographic co-ordinate system). The Neoproterozoic to lowermost Cambrian age of the Svrchnice Formation, suggested by its comparison with similar rocks in the central part of the Teplá-Barrandian Unit, was confirmed by U-Pb dating. Ages of detrital zircons from the metaconglomerate matrix cluster around two values: Archaean to Paleoproterozoic U/Pb ages between ca. 2580 and 1780 Ma and Neoproterozoic to early Cambrian ages between 660 and 520 Ma with a significant peaks at 600 and 544 Ma suggesting local volcanic activity extending shortly beyond the Proterozoic/Paleozoic boundary. Zircons separated from two trondhjemite pebbles from the metaconglomerate

  7. The Cadomian Orogeny and the opening of the Rheic Ocean: The diacrony of geotectonic processes constrained by LA-ICP-MS U Pb zircon dating (Ossa-Morena and Saxo-Thuringian Zones, Iberian and Bohemian Massifs)

    NASA Astrophysics Data System (ADS)

    Linnemann, Ulf; Pereira, Francisco; Jeffries, Teresa E.; Drost, Kerstin; Gerdes, Axel

    2008-12-01

    Cadomian orogenic processes and their continuum to the opening of the Rheic Ocean were modeled by making use of new LA-ICP-MS U-Pb ages from detrital zircons of sedimentary rocks of Late Neoproterozoic (Ediacaran) and Cambro-Ordovician sediments of the Ossa-Morena Zone (Iberian Massif) compared with those from the Saxo-Thuringian Zones (Bohemian Massif). Presented data constrain a diachrony of Cadomian and related geotectonic processes along the northern realm of the Gondwana Supercontinent. Early stage of Cadomian evolution is characterized by a continental magmatic arc at the periphery of the West African Craton and a related back-arc basin opened at c. 590 to 570 Ma. Diacronic arc-continent collision was caused by oblique vector of subduction and started first in the East of Peri-Gondwana at c. 560-570 Ma and resulted at c. 543 Ma in the formation of a short-lived Cadomian retro-arc basin in the Saxo-Thuringian Zone. In contrast, more to the West in the Ossa-Morena Zone, the Cadomian back-arc basin was longer active, at least until c. 545 Ma. In that region, final magmatic pulse of the Cadomian magmatic arc at c. 550 Ma is documented by new zircon data. Closure of the Cadomian back-arc basin and arc-continent collision in the Ossa-Morena Zone occurred between c. 545 Ma and the overall onset of Cambrian plutonism at c. 540 Ma. A mid-oceanic ridge was subducted underneath the Cadomian orogen accompanied by slab break-off of the subducted oceanic plate. Oblique incision of the oceanic ridge into the continent caused the formation of rift basins during the Lower to Middle Cambrian (c. 530-500 Ma). This process continued and finally caused the opening of the Rheic Ocean documented by thick Lower Ordovician siliciclastic sediments and a final magmatic event at c. 490-485 Ma. Opening of the Cambrian rift basin and of the Rheic Ocean again was diachronic and started from the West of Peri-Gondwana and expanded eastward.

  8. Geochemical characteristics and petrogenesis of phonolites and trachytic rocks from the České Středohoří Volcanic Complex, the Ohře Rift, Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Ackerman, Lukáš; Ulrych, Jaromír; Řanda, Zdeněk; Erban, Vojtěch; Hegner, Ernst; Magna, Tomáš; Balogh, Kadosa; Frána, Jaroslav; Lang, Miloš; Novák, Jiří K.

    2015-05-01

    distinct fluids are implicated from the Li-Cs correlations. The derivation of these melts/liquids from sedimentary and/or meta-sedimentary crustal sources is underscored by variable but overall light Li isotopic compositions. Some phonolites exhibit enrichments in high-field-strength elements coupled with increased Zr/Nb ratios. In contrast to previous studies, we show that this feature, apparent in many volcanic rocks from the Bohemian Massif, can be explained with progressive melt fractionation of parental magmas involving amphibole and plagioclase.

  9. Evolution of the Chilka Lake granulite complex, northern Eastern Ghats Belt, India: First evidence of ~ 780 Ma decompression of the deep crust and its implication on the India-Antarctica correlation

    NASA Astrophysics Data System (ADS)

    Bose, S.; Das, K.; Torimoto, J.; Arima, M.; Dunkley, D. J.

    2016-10-01

    High-grade para- and orthogneissic rocks near the Chilka Lake granulite complex, northern part of the Eastern Ghats Belt show complex structural and petrological history. Based on field and petrographic characters, five (M1-M5) metamorphic events could be identified. The earliest metamorphic event (M1) produced amphibolite grade mineral assemblage which produced the peak granulite (M2) assemblages at 900-950 °C, 8.5-9.0 kbar. The third metamorphic event caused decompression of the deeper crust up to 700-800 °C, 6.0-6.5 kbar. This was followed by cooling (M4) and subsequent thermal overprinting (M5). Fluid-composition during M3 was dominated by high-density CO2 and changed to low-density mixed CO2-H2O during the M3. Zircon U-Pb SHRIMP data suggest 781 ± 9 Ma age for M3 event. Texturally constrained monazite U-Th-Pb EPMA data, on the other hand, yield a group age of 988 ± 23 Ma from grain interior, which can signifies the age of M2 event. Few spots with younger dates in the range of 550-500 Ma are also noted. This interpretation changes the existing tectonothermal history of northern Eastern Ghats Belt. Our data show that the two adjacent crustal domains of the Eastern Ghats Belt show distinctly contrasting Neoproterozoic histories. While the central Domain 2 evolved through early anticlockwise P-T path culminating in ultrahigh temperature, the northern Domain 3 evolved through a clockwise P-T path. It appears that the Domain 3 was contiguous to East Antarctica and became part of the Eastern Ghats Belt during the assembly of Gondwana. The ca. 780 Ma decompression event in the northern Eastern Ghats Belt opens up new possibilities for interpreting the breakup of Rodinia.

  10. Anticlockwise P-T evolution at ∼280 Ma recorded from ultrahigh-temperature metapelitic granulite in the Chinese Altai orogenic belt, a possible link with the Tarim mantle plume?

    NASA Astrophysics Data System (ADS)

    Tong, Laixi; Xu, Yi-Gang; Cawood, Peter A.; Zhou, Xin; Chen, Yibing; Liu, Zhao

    2014-11-01

    An ultrahigh-temperature (UHT) metapelitic granulite assemblage consisting of garnet(g)-spinel(sp)-orthopyroxene(opx)-sillimanite(sil)-cordierite(cd)-ilmenite(ilm)-biotite(bi)-plagioclase(pl)-quartz(q) occurs within migmatitic paragneiss near Kalasu in the Chinese Altai, NW China. Textural relations, mineral compositions and P-T estimates, indicate three stages of mineral assemblages: (1) pre-peak prograde stage (M1) consisting of a sp-sil-bearing or sp-opx-bearing inclusion assemblage, with low-Al2O3 contents (4-5 wt.%) in orthopyroxene and P-T conditions of ∼7 kbar and ∼890 °C, (2) peak UHT stage (M2) comprising a g-opx-cd-bearing coarse-grained assemblage, with high-Al2O3 contents (8-9 wt.%) in orthopyroxene and peak conditions of ∼8 kbar and ∼970 °C, and (3) post-peak HT stage (M3) containing an oriented opx-bi-sil-bearing assemblage in matrix, with moderate amounts of Al2O3 (6-7 wt.%) in orthopyroxene and P-T conditions of 8-9 kbar and ∼870 °C. The three discrete stages define an anticlockwise P-T path involving initial prograde heating and post-peak near isobaric cooling. Such a near isobaric cooling anticlockwise P-T path suggests that UHT metamorphism likely occurred in an overall extensional tectonic setting with associated underplating of mantle-derived mafic magma. A SHRIMP zircon U-Pb age of 278 ± 2 Ma obtained from the metapelitic granulite indicates UHT metamorphism in the Altai orogen occurred during the Permian, coeval with spacially associated mantle-derived mafic intrusions (∼280 Ma) and the Tarim mantle plume (∼275 Ma). Thus, the Permian UHT metamorphism of the Chinese Altai is likely associated with underplating and heating of mantle-derived mafic magma as a result of the Tarim mantle plume.

  11. [Body contouring].

    PubMed

    Krüger, N; Lübberding, S; Sattler, G

    2015-10-01

    In our contemporary postmodern society, a modified perception of the human body is accompanied by an increasing demand for body shaping procedures. The treatment needs to be effective but it is just as important that they are safe and can be easily integrated into the daily working and routine schedule. While the options for minimally invasive volume addition are largely limited to injectable implants based on hyaluronic acid or autologous fat, a multitude of options are available for volume reduction. Before deciding on the method of choice, the following needs to be considered: which indications need to be treated, the extent of the reduction in volume and how much pain and possible undesired reactions the patient is prepared to accept.

  12. Lewy bodies

    PubMed Central

    Shults, Clifford W.

    2006-01-01

    Lewy bodies (LB) in the substantia nigra are a cardinal pathological feature of Parkinson's disease, but they occur in a number of neurodegenerative diseases and can be widespread in the nervous system. The characteristics, locations, and composition of LB are reviewed, with particular attention to α-synuclein (α-SYN), which appears to be the major component of LB. The propensity for α-SYN, a presynaptic protein widely expressed in the brain, to aggregate is because of an amyloidogenic central region. The factors that favor the aggregation of α-SYN and mechanisms of toxicity are examined, and a mechanism through which aggregates of α-SYN could induce mitochondrial dysfunction and/or release of proapoptotic molecules is proposed. PMID:16449387

  13. Late Devonian - Early Carboniferous polyphase metamorphic evolution of the Orlica-Śnieżnik Dome (NE Bohemian Massif, Poland): evidence from Th-U-total Pb monazite dating

    NASA Astrophysics Data System (ADS)

    Budzyń, Bartosz; Jastrzębski, Mirosław; Stawikowski, Wojciech

    2014-05-01

    The Orlica-Śnieżnik Dome, located in the NE part of the Bohemian Massif, mainly consists of Cambro-Ordovician orthogneisses and the metavolcano-sedimentary Młynowiec and Stronie Formations. This study constrains electron microprobe Th-U-total Pb ages of monazite in (1) orthogneisses, (2) paragneisses of the Młynowiec Formation (MF), (3) mica schists of the Stronie Formation (SF) and (4) light quartzites. The latter light quartzites form a continuous 'horizon' between two metavolcano-sedimentary formations, however, they are traditionally treated as the lowest member of the Stronie Formation (SF). Our field and structural studies conducted along the transects crossing the boundaries between the above-mentioned rocks indicate that there is a stratigraphic and structural continuity between the Młynowiec and Stronie Formations. Samples for the monazite dating were collected at different distances from the contact between orthogneisses and metasediments. The aim of this study was to provide a new data to verify a hypothesis of Cambro-Ordovician contact or regional metamorphism of the Młynowiec-Stronie Group and to constrain age of the Variscan metamorphic events in the Orlica-Śnieżnik Dome. Monazite from medium-grained orthogneiss yield dates ranging from 546 to 322 Ma, while three age domains of ca. 481 Ma, ca. 421 Ma and ca. 370 Ma are defined in fine-grained orthogneiss. Monazite in two porphyroblastic paragneisses (MF) yields two age domains of 369-361 Ma and 340-336 Ma. It should be noted that the older ages are recorded by inclusions of monazite in staurolite and plagioclase, as well as by matrix monazite. Monazite in leucosome of the migmatized paragneiss (MF) yields ca. 337 Ma age, while matrix monazite in melanosome yields ages of ca. 331 Ma age and a faint record of ca. 355 Ma. In two K-feldspar bearing light quartzites (SF), older spectrum of ages within 524-463 Ma, as well as younger ages of ca. 358 Ma and 347 Ma are obtained. On the other hand, only

  14. Very high-density carbonic fluid inclusions in sapphirine-bearing granulites from Tonagh Island in the Archean Napier Complex, East Antarctica: implications for CO2 infiltration during ultrahigh-temperature (T>1,100 °C) metamorphism

    NASA Astrophysics Data System (ADS)

    Tsunogae, Toshiaki; Santosh, M.; Osanai, Yasuhito; Owada, Masaaki; Toyoshima, Tsuyoshi; Hokada, Tomokazu

    2002-02-01

    The ultrahigh-temperature (UHT) metamorphism of the Napier Complex is characterized by the presence of dry mineral assemblages, the stability of which requires anhydrous conditions. Typically, the presence of the index mineral orthopyroxene in more than one lithology indicates that H2O activities were substantially low. In this study, we investigate a suite of UHT rocks comprising quartzo-feldspathic garnet gneiss, sapphirine granulite, garnet-orthopyroxene gneiss, and magnetite-quartz gneiss from Tonagh Island. High Al contents in orthopyroxene from sapphirine granulite, the presence of an equilibrium sapphirine-quartz assemblage, mesoperthite in quartzo-feldspathic garnet gneiss, and an inverted pigeonite-augite assemblage in magnetite-quartz gneiss indicate that the peak temperature conditions were higher than 1,000 °C. Petrology, mineral phase equilibria, and pressure-temperature computations presented in this study indicate that the Tonagh Island granulites experienced maximum P-T conditions of up to 9 kbar and 1,100 °C, which are comparable with previous P-T estimates for Tonagh and East Tonagh Islands. The textures and mineral reactions preserved by these UHT rocks are consistent with an isobaric cooling (IBC) history probably following an counterclockwise P-T path. We document the occurrence of very high-density CO2-rich fluid inclusions in the UHT rocks from Tonagh Island and characterize their nature, composition, and density from systematic petrographic and microthermometric studies. Our study shows the common presence of carbonic fluid inclusions entrapped within sapphirine, quartz, garnet and orthopyroxene. Analysed fluid inclusions in sapphirine, and some in garnet and quartz, were trapped during mineral growth at UHT conditions as 'primary' inclusions. The melting temperatures of fluids in most cases lie in the range of -56.3 to -57.2 °C, close to the triple point for pure CO2 (-56.6 °C). The only exceptions are fluid inclusions in magnetite

  15. [Multifaceted body. I. The bodies of medicine].

    PubMed

    Saraga, M; Bourquin, C; Wykretowicz, H; Stiefel, F

    2015-02-11

    The human body is the object upon which medicine is acting, but also lived reality, image, symbol, representation and the object of elaboration and theory. All these elements which constitute the body influence the way medicine is treating it. In this series of three articles, we address the human body from various perspectives: medical (1), phenomenological (2), psychosomatic and socio-anthropological (3). This first article discusses four distinct types of representation of the body within medicine, each related to a specific epistemology and shaping a distinct kind of clinical legitimacy: the body-object of anatomy, the body-machine of physiology, the cybernetic body of biology, the statistical body of epidemiology.

  16. Timing and conditions of regional metamorphism and crustal shearing in the granulite facies basement of south Namibia: Implications for the crustal evolution of the Namaqualand metamorphic basement in the Mesoproterozoic

    NASA Astrophysics Data System (ADS)

    Bial, Julia; Büttner, Steffen; Appel, Peter

    2016-11-01

    Granulite facies basement gneisses from the Grünau area in the Kakamas Domain of the Namaqua-Natal Metamorphic Province in south Namibia show high-grade mineral assemblages, most commonly consisting of garnet, cordierite, sillimanite, alkali feldspar and quartz. Cordierite + hercynitic spinel, and in some places quartz + hercynitic spinel, indicate granulite facies P-T conditions. The peak assemblage equilibrated at 800-850 °C at 4.0-4.5 kbar. Sillimanite pseudomorphs after kyanite1 and late-stage staurolite and kyanite2 indicate that the metamorphic record started and ended within the stability field of kyanite. Monazite in the metamorphic basement gneisses shows a single-phase growth history dated as 1210-1180 Ma, which we interpret as the most likely age of the regional metamorphic peak. This time coincides with the emplacement of granitic plutons in the Grünau region. The ∼10 km wide, NW-SE striking Grünau shear zone crosscuts the metamorphic basement and overprints high-temperature fabrics. In sheared metapelites, the regional metamorphic peak assemblage is largely obliterated, and is replaced by synkinematic biotite2, quartz, alkali feldspar, sillimanite and cordierite or muscovite. In places, gedrite, staurolite, sillimanite and green biotite3 may have formed late- or post-kinematically. The mylonitic mineral assemblage equilibrated at 590-650 °C at 3.5-5.0 kbar, which is similar to a retrograde metamorphic stage in the basement away from the shear zone. Monazite cores in two mylonite samples are similar in texture and age (∼1200 Ma) to monazite in metapelites away from the shear zone. Chemically distinct monazite rims indicate a second growth episode at ∼1130-1120 Ma. This age is interpreted to date the main deformation episode along the Grünau shear zone and the retrograde metamorphic stage seen in the basement. The main episode of ductile shearing along the Grünau shear zone took place 70-80 million years after the thermal peak metamorphism

  17. Body Image and Body Contouring Procedures.

    PubMed

    Sarwer, David B; Polonsky, Heather M

    2016-10-01

    Dissatisfaction with physical appearance and body image is a common psychological phenomena in Western society. Body image dissatisfaction is frequently reported by those who have excess body weight, but also is seen in those of normal body weight. For both groups of individuals, this dissatisfaction impacts self-esteem and quality of life. Furthermore, it is believed to be the motivational catalyst to a range of appearance-enhancing behaviors, including weight loss efforts and physical activity. Body image dissatisfaction is also believed to play a role in the decision to seek the wide range of body contouring procedures offered by aesthetic physicians. Individuals who seek these procedures typically report increased body image dissatisfaction, focus on the feature they wish to alter with treatment, and often experience improvement in body image following treatment. At the same time, extreme body image dissatisfaction is a symptom of a number of recognized psychiatric disorders. These include anorexia nervosa, bulimia nervosa, and body dysmorphic disorder (BDD), all of which can contraindicate aesthetic treatment. This special topic review paper provides an overview of the relationship between body image dissatisfaction and aesthetic procedures designed to improve body contouring. The review specifically focuses on the relationship of body image and body weight, as well as the presentation of body image psychopathology that would contraindicate aesthetic surgery. The overall goal of the paper is to highlight the clinical implications of the existing research and provide suggestions for future research on the psychological aspects of body contouring procedures.

  18. Body Image and Body Contouring Procedures.

    PubMed

    Sarwer, David B; Polonsky, Heather M

    2016-10-01

    Dissatisfaction with physical appearance and body image is a common psychological phenomena in Western society. Body image dissatisfaction is frequently reported by those who have excess body weight, but also is seen in those of normal body weight. For both groups of individuals, this dissatisfaction impacts self-esteem and quality of life. Furthermore, it is believed to be the motivational catalyst to a range of appearance-enhancing behaviors, including weight loss efforts and physical activity. Body image dissatisfaction is also believed to play a role in the decision to seek the wide range of body contouring procedures offered by aesthetic physicians. Individuals who seek these procedures typically report increased body image dissatisfaction, focus on the feature they wish to alter with treatment, and often experience improvement in body image following treatment. At the same time, extreme body image dissatisfaction is a symptom of a number of recognized psychiatric disorders. These include anorexia nervosa, bulimia nervosa, and body dysmorphic disorder (BDD), all of which can contraindicate aesthetic treatment. This special topic review paper provides an overview of the relationship between body image dissatisfaction and aesthetic procedures designed to improve body contouring. The review specifically focuses on the relationship of body image and body weight, as well as the presentation of body image psychopathology that would contraindicate aesthetic surgery. The overall goal of the paper is to highlight the clinical implications of the existing research and provide suggestions for future research on the psychological aspects of body contouring procedures. PMID:27634782

  19. [Multifaceted body. 2. The lived body].

    PubMed

    Wykretowicz, H; Saraga, M; Bourquin, C; Stiefel, F

    2015-02-11

    The human body is the object upon which medicine is acting, but also lived reality, image, symbol, representation and the object of elaboration and theory. All these elements which constitute the body influence the way medicine is treating it. In this series of three articles, we address the human body from various perspectives: medical (1), phenomenological (2), psychosomatic and socio-anthropological (3). This second article distinguishes between the body as an object of knowledge or representation and the way the body is lived. This distinction which originates in phenomenological psychiatry aims to understand how the patient experiences his body and to surpass the classical somatic and psychiatric classifications. PMID:25895215

  20. [Multifaceted body. 2. The lived body].

    PubMed

    Wykretowicz, H; Saraga, M; Bourquin, C; Stiefel, F

    2015-02-11

    The human body is the object upon which medicine is acting, but also lived reality, image, symbol, representation and the object of elaboration and theory. All these elements which constitute the body influence the way medicine is treating it. In this series of three articles, we address the human body from various perspectives: medical (1), phenomenological (2), psychosomatic and socio-anthropological (3). This second article distinguishes between the body as an object of knowledge or representation and the way the body is lived. This distinction which originates in phenomenological psychiatry aims to understand how the patient experiences his body and to surpass the classical somatic and psychiatric classifications.

  1. [Multifaceted body. I. The bodies of medicine].

    PubMed

    Saraga, M; Bourquin, C; Wykretowicz, H; Stiefel, F

    2015-02-11

    The human body is the object upon which medicine is acting, but also lived reality, image, symbol, representation and the object of elaboration and theory. All these elements which constitute the body influence the way medicine is treating it. In this series of three articles, we address the human body from various perspectives: medical (1), phenomenological (2), psychosomatic and socio-anthropological (3). This first article discusses four distinct types of representation of the body within medicine, each related to a specific epistemology and shaping a distinct kind of clinical legitimacy: the body-object of anatomy, the body-machine of physiology, the cybernetic body of biology, the statistical body of epidemiology. PMID:25895214

  2. [Perspectives on body: embodiment and body image].

    PubMed

    Chang, Shiow-Ru; Chao, Yu-Mei Yu

    2007-06-01

    "Body" is a basic concept of both the natural and human sciences. This extensive review of the literature explores the various philosophical approaches to the body, including empiricism, idealism, existentialism and phenomenology, as well as the relationship between body and mind. Embodiment and body image are the two main concepts of body addressed in this article. Merleau-Ponty's perspective on embodiment, an important new area of theory development, emphasizes that embodiment research must focus on life experiences, such as the study of body image. Using Schilder's framework of psychosocialology, this article provides a comprehensive understanding of the concept of body image and women's perspectives on the "body" in both Western culture and Eastern cultures. Body size and shape significantly influence the self-image of women. Body image is something that develops and changes throughout one's life span and is continually being constructed, destructed, and reconstructed. Personal body image has important psychological effects on the individual, especially women. This integrative review can make a significant contribution to knowledge in this area and, consequently, to related practice and research.

  3. Lewy Body Disease

    MedlinePlus

    Lewy body disease is one of the most common causes of dementia in the elderly. Dementia is the loss of mental ... to affect normal activities and relationships. Lewy body disease happens when abnormal structures, called Lewy bodies, build ...

  4. Body Composition Tests

    MedlinePlus

    ... more bone and muscle will weigh more in water than a person with less bone and muscle. The volume of the body is calculated and body density and body fat percentage are calculated. This technique ...

  5. The occurrence of fluor-wagnerite in UHT granulites and its implications towards understanding fluid regimes in the evolution of deep crust: a case study from the Eastern Ghats Belt, India

    NASA Astrophysics Data System (ADS)

    Das, Kaushik; Tomioka, Naotaka; Bose, Sankar; Ando, Jun-ichi; Ohnishi, Ichiro

    2016-09-01

    We report the occurrence of a rare phosphate mineral, fluor-wagnerite (Mg1.91-1.94Fe0.06-0.07Ca<0.01) (P0.99-1.00O4)(OH0.02-0.17F0.98-0.83) from the Eastern Ghats Belt of India, an orogenic belt evolved during Meso- to Neoproterozoic time. The host rock, i.e. high- to ultrahigh temperature (UHT) granulites (~1000 °C, 8-9 kbar) of the studied area was retrogressed after emplacement to mid-crustal level (800-850 °C, 6-6.5 kbar) as deduced from their pressure-temperature histories. Based on mineral chemical data and micro-Raman analyses, we document an unusual high Mg-F-rich chemistry of the F-wagnerite, which occur both in peak metamorphic porphyroblastic assemblages as well as in the retrograde matrix assemblage. Therefore, in absence of other common phosphates like apatite, fluor-wagnerite can act as an indicator for the presence of F-bearing fluids for rocks with high X Mg and/or fO2. The occurrence of F-rich minerals as monitors for fluid compositions has important implications for the onset of biotite dehydration melting and hence melt production in the deep crust. We propose that fluor-wagnerite can occur as an accessory mineral associated with F-rich fluids in lower-mid crustal rocks, and F in coexisting minerals should be taken into consideration when reconciling the petrogenetic grid of biotite-dehydration melting.

  6. Timing of Early Proterozoic collisional and extensional events in the granulite-gneiss-charnockite-granite complex, Lake Baikal, USSR: A U-Pb, Rb-Sr, and Sm-Nd isotopic study

    SciTech Connect

    Aftalion, M. ); Bibikova, E.V. ); Bowes, D.R. ); Hopwood, A.M. ); Perchuk, L.L. )

    1991-11-01

    In the Sharyzhalgay Complex of the Lake Baikal region in eastern Siberia Early Proterozoic collisional and extensional events were separated by ca. 100 m.yr. The earlier collisional event, associated with the development of granulites and gneisses as the result of high-grade dynamothermal metamorphism, took place close to 1965 {plus minus} 4 Ma. A {sup 207}Pb/{sup 204}Pb vs. {sup 206}Pb/{sup 204}Pb isochron for zircon from five size fractions and a six point Rb-Sr whole-rock errorchron give generally corresponding ages of 1956 {plus minus} 8 and 1963 {plus minus} 163 Ma, respectively. The later extensional event, associated with charnockitization due to the uprise of fluids and heat in a regime corresponding to the middle to upper crustal levels of a Basin and Range-type province, was initiated in the 1880-1860 Ma period. The event was continued with magmatic emplacement of granitic masses into the deep levels of caldera-like structures, possibly during the upper time range of lower concordia intercept ages of 1817 +30/{minus}32 and 1797 +40/{minus}44 Ma for two distinctly different zircon populations in a pyroxene-bearing granodiorite interpreted as an evolved (and contaminated) product of the mantle-derived magma that was the source of CO{sub 2} involved in the charnockitization. Upper intercept ages of 2784 +48/{minus}45 and 2775 +61/{minus}55 Ma indicate late Archean crust at depth as the source region of the incorporated zircon. T{sub DM} ages from Sm-Nd isotopic data show that the protolith of the lithologically layered supracrustal assemblage, subsequently polyphase deformed and polymetamorphosed in Early Proterozoic times, was also formed in Early Proterozoic (not Archean) times.

  7. Timing and rate of granulite facies metamorphism and cooling from multi-mineral chronology on migmatitic gneisses, Sierras de La Huerta and Valle Fértil, NW Argentina

    NASA Astrophysics Data System (ADS)

    Gallien, Florian; Mogessie, Aberra; Bjerg, Ernesto; Delpino, Sergio; de Machuca, Brigida Castro; Thöni, Martin; Klötzli, Urs

    2010-01-01

    Migmatitic paragneisses of the Valle Fértil-La Huerta Ranges at the Western margin of the Sierras Pampeanas are composed of garnet-cordierite-plagioclase-biotite-quartz-bearing units that experienced peak metamorphic conditions of ca. 800 °C at 6-7 kbar. Based on petrological studies, pseudosection modeling and petrographic observations, an anticlockwise P- T path with a small pressure increment is proposed. Rare earth element LA-ICP-MS patterns acquired from rutile bearing garnets suggest a single stage of garnet growth at high- T at pressures above the ilmenite-rutile transition. U-Pb dating of zircon rims from the migmatites indicates two distinct metamorphic U-Pb ages of 525 ± 9 Ma and 478 ± 9 Ma. The older age is suggested to record an amphibolite facies event of the Pampean orogeny. The younger metamorphic age is contemporary with igneous zircons from metatonalites and pegmatites that yield 478 ± 4 Ma. We suggest that the prograde high- T metamorphic Famatinian event is associated with the emplacement of large magmatic bodies in which large-scale magmatic activity gave rise to an increased geothermal gradient of about 35 °C/km. Sm-Nd garnet ages of 447 ± 3 Ma indicate a time span of around 30 Ma for which temperatures above the garnet closure temperature prevailed. Using U-Pb, Sm-Nd and Rb-Sr isotope systems, a cooling rate of 3 to 6 °C/Myr is inferred.

  8. [Multifaceted body. 3. The contextualised body].

    PubMed

    Bourquin, C; Wykretowicz, H; Saraga, M; Stiefel, F

    2015-02-11

    The human body is the object upon which medicine is acting, but also lived reality, image, symbol, representation and the object of elaboration and theory. All these elements which constitute the body influence the way medicine is treating it. In this series of three articles, we address the human body from various perspectives: medical (1), phenomenological (2), psychosomatic and socio-anthropological (3). This third and last article focuses on the psychosomatic and socio-anthropological facets of the body and their contribution to its understanding. PMID:25895216

  9. [Multifaceted body. 3. The contextualised body].

    PubMed

    Bourquin, C; Wykretowicz, H; Saraga, M; Stiefel, F

    2015-02-11

    The human body is the object upon which medicine is acting, but also lived reality, image, symbol, representation and the object of elaboration and theory. All these elements which constitute the body influence the way medicine is treating it. In this series of three articles, we address the human body from various perspectives: medical (1), phenomenological (2), psychosomatic and socio-anthropological (3). This third and last article focuses on the psychosomatic and socio-anthropological facets of the body and their contribution to its understanding.

  10. Adolescence and Body Image.

    ERIC Educational Resources Information Center

    Weinshenker, Naomi

    2002-01-01

    Discusses body image among adolescents, explaining that today's adolescents are more prone to body image distortions and dissatisfaction than ever and examining the historical context; how self-image develops; normative discontent; body image distortions; body dysmorphic disorder (BDD); vulnerability of boys (muscle dysmorphia); who is at risk;…

  11. Body Image and Body Dysmorphic Concerns.

    PubMed

    Tomas-Aragones, Lucia; Marron, Servando E

    2016-08-23

    Most people would like to change something about their bodies and the way that they look, but for some it becomes an obsession. A healthy skin plays an important role in a person's physical and mental wellbeing, whereas a disfiguring appearance is associated with body image concerns. Skin diseases such as acne, psoriasis and vitiligo produce cosmetic disfigurement and patients suffering these and other visible skin conditions have an increased risk of depression, anxiety, feelings of stigmatization and self-harm ideation. Body image affects our emotions, thoughts, and behaviours in everyday life, but, above all, it influences our relationships. Furthermore, it has the potential to influence our quality of life. Promotion of positive body image is highly recommended, as it is important in improving people's quality of life, physical health, and health-related behaviors. Dermatologists have a key role in identifying body image concerns and offering patients possible treatment options. PMID:27283435

  12. "You have no good blood in your body". Oral communication in sixteenth-century physicians' medical practice.

    PubMed

    Stolberg, Michael

    2015-01-01

    In his personal notebooks, the little known Bohemian physician Georg Handsch (1529-c. 1578) recorded, among other things, hundreds of vernacular phrases and expressions he and other physicians used in their oral interaction with patients and families. Based primarily on this extraordinary source, this paper traces the terms, concepts and images to which sixteenth-century physicians resorted when they explained the nature of a patient's disease and justified their treatment. At the bedside and in the consultation room, Handsch and his fellow physicians attributed most diseases to a local accumulation of impure, putrid or otherwise pathological humours. The latter were commonly said to result, in turn, from an insufficient concoction and assimilation of food and drink in the stomach and the liver or from an obstruction of the humoral flow inside the body and across its borders. By contrast, other notions and explanatory models, which had a prominent place in contemporary learned medical writing, hardly played a role at all in the physicians' oral communication. Specific disease terms were rarely used, a mere imbalance of the four natural humours in the body was almost never inculpated, and the patient's personal life-style and other non-naturals did not attract much attention either. These striking differences between the ways in which physicians explained the patients' diseases in their daily practice and the explanatory models we find in contemporary textbooks, are attributed, above all, to the physicians' precarious situation in the early modern medical marketplace. Since dissatisfied patients were quick to turn to another healer, physicians had to explain the disease and justify their treatment in a manner that was comprehensible to ordinary lay people and in line with their expectations and beliefs, which, at the time, revolved almost entirely around notions of impurity and evacuation.

  13. Stereometric body volume measurement

    NASA Technical Reports Server (NTRS)

    Herron, R. E.

    1975-01-01

    The following studies are reported: (1) effects of extended space flight on body form of Skylab astronauts using biostereometrics; (2) comparison of body volume determinations using hydrostatic weighing and biostereometrics; and (3) training of technicians in biostereometric principles and procedures.

  14. Inclusion Body Myositis

    MedlinePlus

    ... What is Inclusion Body Myositis? Inclusion body myositis (IBM) is one of a group of muscle diseases ... muscle weakness. The onset of muscle weakness in IBM is generally gradual (over months or years) and ...

  15. Body mass index

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/007196.htm Body mass index To use the sharing features on this ... your height is to figure out your body mass index (BMI). You and your health care provider ...

  16. Inside Your Body

    MedlinePlus

    ... sweeping things like dust out of the body. Endocrine system The endocrine (say: EN-doh-krun) system is ... to tissues and organs throughout the body. The endocrine system makes sure that there is the right amount ...

  17. Lewy Body Dementia Research

    MedlinePlus

    ... Alzheimer's when Lewy Bodies are present Lewy body pathology is found in up to 50% of cases ... between people who have autopsy-verified Alzheimer’s disease pathology alone versus those who have both Alzheimer’s and ...

  18. Lewy Body Dementia Diagnosis

    MedlinePlus

    ... individuals, it may also be due to the natural course of the disease. All Rights Reserved Lewy Body Dementia Association, Inc. 912 Killian Hill Road S.W., Lilburn, GA 30047 © 2016 Lewy Body Dementia Association, Inc. Connect ...

  19. Foreign Body Retrieval

    MedlinePlus

    ... extended over the patient while an x-ray film holder or image recording plate is placed beneath ... through the body, recording an image on photographic film or a special detector. Many foreign bodies, like ...

  20. Avatar body dimensions and men's body image.

    PubMed

    Cacioli, Jon-Paul; Mussap, Alexander J

    2014-03-01

    Two online surveys examined the significance of the visual analogues, or 'avatars', men (total N=266) create and use online. Two-dimensional (adiposity×muscle) somatomorphic matrices revealed that avatars are generally thinner than their creator's actual body and similar to their ideal, but more muscular than either their actual or ideal. Men's ratings of the importance of their avatar's appearance correlated with their actual weight and muscle concerns, and disparity between their avatar and actual body dimensions predicted their offline context body change concerns additional to that accounted for by disparity between their ideal and actual bodies. Together with the observation that men also reported higher self-esteem, less social interaction anxiety and less social phobia while online (which correlated with the time they spent online), these results suggest that the physical dimensions of avatars used in social interactions online may serve a compensatory function.

  1. Avatar body dimensions and men's body image.

    PubMed

    Cacioli, Jon-Paul; Mussap, Alexander J

    2014-03-01

    Two online surveys examined the significance of the visual analogues, or 'avatars', men (total N=266) create and use online. Two-dimensional (adiposity×muscle) somatomorphic matrices revealed that avatars are generally thinner than their creator's actual body and similar to their ideal, but more muscular than either their actual or ideal. Men's ratings of the importance of their avatar's appearance correlated with their actual weight and muscle concerns, and disparity between their avatar and actual body dimensions predicted their offline context body change concerns additional to that accounted for by disparity between their ideal and actual bodies. Together with the observation that men also reported higher self-esteem, less social interaction anxiety and less social phobia while online (which correlated with the time they spent online), these results suggest that the physical dimensions of avatars used in social interactions online may serve a compensatory function. PMID:24394638

  2. Literacies in the Body

    ERIC Educational Resources Information Center

    Jones, Stephanie

    2013-01-01

    In this commentary, the author invites readers to consider the body and its central place in literacy pedagogy, practice and research. She emphasizes two interrelated paths for teachers and researchers interested in literacies to tend to the body: (1) the ways literacies are engaged and cultivated for making sense of bodies, and (2) the literacies…

  3. Coiled bodies without coilin.

    PubMed Central

    Bauer, D W; Gall, J G

    1997-01-01

    Nuclei assembled in vitro in Xenopus egg extract contain coiled bodies that have components from three different RNA processing pathways: pre-mRNA splicing, pre-rRNA processing, and histone pre-mRNA 3'-end formation. In addition, they contain SPH-1, the Xenopus homologue of p80-coilin, a protein characteristic of coiled bodies. To determine whether coilin is an essential structural component of the coiled body, we removed it from the egg extract by immunoprecipitation. We showed that nuclei with bodies morphologically identical to coiled bodies (at the light microscope level) formed in such coilin-depleted extract. As expected, these bodies did not stain with antibodies against coilin. Moreover, they failed to stain with an antibody against the Sm proteins, although Sm proteins associated with snRNAs were still present in the extract. Staining of the coilin- and Sm-depleted coiled bodies was normal with antibodies against two nucleolar proteins, fibrillarin and nucleolin. Similar results were observed when Sm proteins were depleted from egg extract: staining of the coiled bodies with antibodies against the Sm proteins and coilin was markedly reduced but bright nucleolin and fibrillarin staining remained. These immunodepletion experiments demonstrate an interdependence between coilin and Sm snRNPs and suggest that neither is essential for assembly of nucleolar components in coiled bodies. We propose that coiled bodies are structurally heterogeneous organelles in which the components of the three RNA processing pathways may occur in separate compartments. Images PMID:9017596

  4. Body, biometrics and identity.

    PubMed

    Mordini, Emilio; Massari, Sonia

    2008-11-01

    According to a popular aphorism, biometrics are turning the human body into a passport or a password. As usual, aphorisms say more than they intend. Taking the dictum seriously, we would be two: ourself and our body. Who are we, if we are not our body? And what is our body without us? The endless history of identification systems teaches that identification is not a trivial fact but always involves a web of economic interests, political relations, symbolic networks, narratives and meanings. Certainly there are reasons for the ethical and political concerns surrounding biometrics but these reasons are probably quite different from those usually alleged.

  5. Biogenesis of nuclear bodies.

    PubMed

    Dundr, Miroslav; Misteli, Tom

    2010-12-01

    The nucleus is unique amongst cellular organelles in that it contains a myriad of discrete suborganelles. These nuclear bodies are morphologically and molecularly distinct entities, and they host specific nuclear processes. Although the mode of biogenesis appears to differ widely between individual nuclear bodies, several common design principles are emerging, particularly, the ability of nuclear bodies to form de novo, a role of RNA as a structural element and self-organization as a mode of formation. The controlled biogenesis of nuclear bodies is essential for faithful maintenance of nuclear architecture during the cell cycle and is an important part of cellular responses to intra- and extracellular events.

  6. Nucleation of nuclear bodies.

    PubMed

    Dundr, Miroslav

    2013-01-01

    The nucleus is a complex organelle containing numerous highly dynamic, structurally stable domains and bodies, harboring functions that have only begun to be defined. However, the molecular mechanisms for their formation are still poorly understood. Recently it has been shown that a nuclear body can form de novo by self-organization. But little is known regarding what triggers the formation of a nuclear body and how subsequent assembly steps are orchestrated. Nuclear bodies are frequently associated with specific active gene loci that directly contribute to their formation. Both coding and noncoding RNAs can initiate the assembly of nuclear bodies with which they are physiologically associated. Thus, the formation of nuclear bodies occurs via recruitment and consequent accumulation of resident proteins in the nuclear bodies by nucleating RNA acting as a seeder. In this chapter I describe how to set up an experimental cell system to probe de novo biogenesis of a nuclear body by nucleating RNA and nuclear body components tethered on chromatin. PMID:23980018

  7. Body perception in newborns.

    PubMed

    Filippetti, Maria Laura; Johnson, Mark H; Lloyd-Fox, Sarah; Dragovic, Danica; Farroni, Teresa

    2013-12-01

    Body ownership and awareness has recently become an active topic of research in adults using paradigms such as the "rubber hand illusion" and "enfacement" [1-11]. These studies show that visual, tactile, postural, and anatomical information all contribute to the sense of body ownership in adults [12]. While some hypothesize body perception from birth [13], others have speculated on the importance of postnatal experience [14, 15]. Through studying body perception in newborns, we can directly investigate the factors involved prior to significant postnatal experience. To address this issue, we measured the looking behavior of newborns presented with visual-tactile synchronous and asynchronous cues, under conditions in which the visual information was either an upright (body-related stimulus; experiment 1) or inverted (non-body-related stimulus; experiment 2) infant face. We found that newborns preferred to look at the synchronous condition compared to the asynchronous condition, but only when the visual stimulus was body related. These results are in line with findings from adults and demonstrate that human newborns detect intersensory synchrony when related to their own bodies, consistent with the basic processes underlying body perception being present at birth. PMID:24268410

  8. The Body Bites Back!

    ERIC Educational Resources Information Center

    Alsop, Steve

    2011-01-01

    How should we think about the body in science education? What ought it mean to be alive and live within epistemologies and pedagogies? What does it mean to be human in science education? In response to Auli Arvola Orlander and Per-Olof Wickram's article, this essay explores some of the possibilities and questions that the body evokes in science…

  9. Disorders of body temperature.

    PubMed

    Gomez, Camilo R

    2014-01-01

    The human body generates heat capable of raising body temperature by approximately 1°C per hour. Normally, this heat is dissipated by means of a thermoregulatory system. Disorders resulting from abnormally high or low body temperature result in neurologic dysfunction and pose a threat to life. In response to thermal stress, maintenance of normal body temperature is primarily maintained by convection and evaporation. Hyperthermia results from abnormal temperature regulation, leading to extremely elevated body temperature while fever results from a normal thermoregulatory mechanism operating at a higher set point. The former leads to specific clinical syndromes with inability of the thermoregulatory mechanism to maintain a constant body temperature. Heat related illness encompasses heat rash, heat cramps, heat exhaustion and heat stroke, in order of severity. In addition, drugs can induce hyperthermia and produce one of several specific clinical syndromes. Hypothermia is the reduction of body temperature to levels below 35°C from environmental exposure, metabolic disorders, or therapeutic intervention. Management of disorders of body temperature should be carried out decisively and expeditiously, in order to avoid secondary neurologic injury.

  10. Body Basics Library

    MedlinePlus

    ... for Parents for Kids for Teens Teens Home Body Mind Sexual Health Food & Fitness Diseases & Conditions Infections Q&A School & Jobs Drugs & Alcohol Staying Safe Recipes En Español Making a Change – Your ... KidsHealth > For Teens > About the Body ...

  11. [Body and philosophy].

    PubMed

    Paturet, Jean-Bernard

    2011-06-01

    Reflections on the body and its representations have marked every era throughout the history of mankind. Philosophical, religious, political, social, etc. the body is multi-faceted. It is a "living object" which is part of the fabric of the world.

  12. Porous body infiltrating method

    DOEpatents

    Corman, Gregory Scot

    2002-01-01

    A mixture is formed that comprises at least some to about 10 wt % boron nitride and silicon. A body comprising a component that is wetted by or reacts with silicon is contacted with the mixture and the contacted body is infiltrated with silicon from the mixture.

  13. Teaching Bodies in Place

    ERIC Educational Resources Information Center

    Jones, Stephanie; Woglom, James F.

    2013-01-01

    Background/Context: This piece draws on literature in justice-oriented teacher education, feminist pedagogy, and postmodern notions of bodies and place to make sense of data generated from a three-year study of an undergraduate teacher education course. A feminist lens was used to engage a body- and place-focused pedagogy that aimed to engage…

  14. The Cajal Body and Histone Locus Body

    PubMed Central

    Nizami, Zehra; Deryusheva, Svetlana; Gall, Joseph G.

    2010-01-01

    The Cajal body (CB) is a nuclear organelle present in all eukaryotes that have been carefully studied. It is identified by the signature protein coilin and by CB-specific RNAs (scaRNAs). CBs contain high concentrations of splicing small nuclear ribonucleoproteins (snRNPs) and other RNA processing factors, suggesting that they are sites for assembly and/or posttranscriptional modification of the splicing machinery of the nucleus. The histone locus body (HLB) contains factors required for processing histone pre-mRNAs. As its name implies, the HLB is associated with the genes that code for histones, suggesting that it may function to concentrate processing factors at their site of action. CBs and HLBs are present throughout the interphase of the cell cycle, but disappear during mitosis. The biogenesis of CBs shows the features of a self-organizing structure. PMID:20504965

  15. The body as art.

    PubMed

    Barker, D J; Barker, M J

    2002-07-01

    For millennia people have altered the appearance of their bodies with cosmetics, jewellery, tattoos, piercings, and other surgical procedures. It would appear that they wish to conform to a perceived 'ideal body', although the actual appearance of such a body is subject to temporal, cultural and geographical change. In contemporary society the media are largely responsible for providing the yardsticks against which individual body shape is measured. Today the desired form is generally young, slim, tanned and blemish-free. Sadly, dissatisfaction with body image can be the source of great unhappiness and may even lead to suicide. Interested scholars have debated the meaning of beauty for centuries but it seems that every human society has its own standards. At the simplest it would appear that youth and symmetry are the most highly prized ingredients. There is no doubt that those who fit the conventional standards of attractiveness are treated better by society. Individuals have an inalienable right to their own body appearance, and to alter it as they see fit, however such modifications may not always be in their own best interests. Practitioners of cosmetic procedures must be alert to clients with histories of weight fluctuation, unrealistic body image, or low self-esteem. Psychological disorders may present with dysmorphophobic symptoms. Doctors providing cosmetic services need to be adept at diagnosing psychological illness.

  16. Pulmonary blue bodies.

    PubMed

    Koss, M N; Johnson, F B; Hochholzer, L

    1981-03-01

    Pulmonary blue bodies are intra-alveolar laminated basophilic concretions of uncertain etiology. Blue bodies were studied in lung biopsy specimens from 10 patients. The patients ranged in age from 47 to 69 years and were predominantly men. Three had a history of overt exposure to environmental dusts such as sawdust and asbestos, and two showed occasional ferruginous bodies in the lung, raising the possibility of pneumoconiosis. In eight cases there was interstitial pneumonitis, which resembled desquamative interstitial pneumonia by light microscopy but which was often seen to be patchy and asymmetrically distributed in the lung by chest x-ray examination. Of two other patients, one had xanthogranulomatous inflammation and the other, necrotizing granulomatous inflammation. Light and electron microscopic, histochemical, microchemical, and x-ray diffraction studies of blue bodies were also performed. Calcium carbonate is a major component of blue bodies and is responsible for their birefringence in unstained sections and ready solubility in acid solutions. Blue bodies also contain a mucopolysaccharide matrix and iron. We offer the hypothesis that blue bodies (calcium carbonate) are a product of histiocytic catabolism.

  17. The body as art.

    PubMed

    Barker, D J; Barker, M J

    2002-07-01

    For millennia people have altered the appearance of their bodies with cosmetics, jewellery, tattoos, piercings, and other surgical procedures. It would appear that they wish to conform to a perceived 'ideal body', although the actual appearance of such a body is subject to temporal, cultural and geographical change. In contemporary society the media are largely responsible for providing the yardsticks against which individual body shape is measured. Today the desired form is generally young, slim, tanned and blemish-free. Sadly, dissatisfaction with body image can be the source of great unhappiness and may even lead to suicide. Interested scholars have debated the meaning of beauty for centuries but it seems that every human society has its own standards. At the simplest it would appear that youth and symmetry are the most highly prized ingredients. There is no doubt that those who fit the conventional standards of attractiveness are treated better by society. Individuals have an inalienable right to their own body appearance, and to alter it as they see fit, however such modifications may not always be in their own best interests. Practitioners of cosmetic procedures must be alert to clients with histories of weight fluctuation, unrealistic body image, or low self-esteem. Psychological disorders may present with dysmorphophobic symptoms. Doctors providing cosmetic services need to be adept at diagnosing psychological illness. PMID:17147524

  18. Body cooling after death.

    PubMed

    Kuehn, L A; Tikuisis, P; Livingstone, S; Limmer, R

    1980-09-01

    In the analyses of cases of death in cold air environments, it is often of interest to determine the time required for the body of the individual to cool to ambient temperature. Usually such determinations have been based on Newton's law of cooling. This paper describes a case history in which this technique was experimentally tested and consequently abandoned in favour of a more complex biophysical model which more accurately described the thermo-physical events inherent in body cooling. This model is recommended for determination of the times required for various body parts to cool to ambient environmental temperatures.

  19. Foreign Body Granulomas.

    PubMed

    Molina-Ruiz, Ana M; Requena, Luis

    2015-07-01

    A large list of foreign substances may penetrate the skin and induce a foreign body granulomatous reaction. These particles can enter the skin by voluntary reasons or be caused by accidental inclusion of external substances secondary to cutaneous trauma. In these cases, foreign body granulomas are formed around such disparate substances as starch, cactus bristles, wood splinters, suture material, pencil lead, artificial hair, or insect mouthparts. The purpose of this article is to update dermatologists, pathologists, and other physicians on the most recent etiopathogenesis, clinical presentations, systemic associations, evaluation, and evidence-based management concerning foreign body granulomatous reactions of skin. PMID:26143429

  20. Magnetic human body communication.

    PubMed

    Park, Jiwoong; Mercier, Patrick P

    2015-01-01

    This paper presents a new human body communication (HBC) technique that employs magnetic resonance for data transfer in wireless body-area networks (BANs). Unlike electric field HBC (eHBC) links, which do not necessarily travel well through many biological tissues, the proposed magnetic HBC (mHBC) link easily travels through tissue, offering significantly reduced path loss and, as a result, reduced transceiver power consumption. In this paper the proposed mHBC concept is validated via finite element method simulations and measurements. It is demonstrated that path loss across the body under various postures varies from 10-20 dB, which is significantly lower than alternative BAN techniques.

  1. About Body Water

    MedlinePlus

    ... Thoughts As Traffic Piles Up, So Does Air Pollution Heart Docs: Never Expose Kids to Cigarette Smoke ... Insulin Delivery Additional Content Medical News About Body Water By James L. Lewis, III, MD NOTE: This ...

  2. [Towards the bionic body].

    PubMed

    Andrieu, Bernard

    2011-06-01

    Global technological progress is enabling people to see their mutilated bodies assisted by sophisticated prostheses. Multi-disciplinary and associative care help patients relearn daily living activities and accomplish various exploits.

  3. Body Fluids Monitor

    NASA Technical Reports Server (NTRS)

    Siconolfi, Steven F. (Inventor)

    2000-01-01

    Method and apparatus are described for determining volumes of body fluids in a subject using bioelectrical response spectroscopy. The human body is represented using an electrical circuit. Intra-cellular water is represented by a resistor in series with a capacitor; extra-cellular water is represented by a resistor in series with two parallel inductors. The parallel inductors represent the resistance due to vascular fluids. An alternating, low amperage, multifrequency signal is applied to determine a subject's impedance and resistance. From these data, statistical regression is used to determine a 1% impedance where the subject's impedance changes by no more than 1% over a 25 kHz interval. Circuit component, of the human body circuit are determined based on the 1% impedance. Equations for calculating total body water, extra-cellular water, total blood volume, and plasma volume are developed based on the circuit components.

  4. Lewy Body Dementia Association

    MedlinePlus

    ... promoting scientific advances. Featured LBD Stories & Tributes Dad's Dementia Journey It's been years since my father passed ... I received an email from the Lewy Body Dementia Association about a benefit... Read Story The Lewy ...

  5. Body Mass Index Table

    MedlinePlus

    ... Families ( We Can! ) Health Professional Resources Body Mass Index Table 1 for BMI greater than 35, go ... to content Twitter Facebook YouTube Google+ SEARCH | SITE INDEX | ACCESSIBILITY | PRIVACY STATEMENT | FOIA | OIG | CONTACT US National ...

  6. [Foreign body stories].

    PubMed

    Stenz, Volker; Thurnheer, Robert; Widmer, Fritz; Krause, Martin

    2008-12-01

    Gastrointestinal and bronchial foreign bodies may cause significant clinical complications with a high degree of morbidity. In adults, a large variety of foreign bodies are accidentally or intentionally ingested, inserted or aspirated. In the majority of cases, the objects are expelled conservatively by coughing, vomiting or bowel movements. The risk for obstruction, perforation and penetration depends upon the type of object, those with sharp edges or tips having the highest risk. In these situations, the objects have to be removed by an endoscopic or an operative intervention. We present four foreign body stories including a young lady who swallowed a pen during sleep, a farmer who inserted a corncob into the rectum because of intractable diarrhoea, an elderly gentleman who aspirated a dental bridge while laughing and a cocain body packer who was caught at the border. Back ground, complications and removal procedures of the four cases are discussed.

  7. Multichannel Human Body Communication

    NASA Astrophysics Data System (ADS)

    Przystup, Piotr; Bujnowski, Adam; Wtorek, Jerzy

    2016-01-01

    Human Body Communication is an attractive alternative for traditional wireless communication (Bluetooth, ZigBee) in case of Body Sensor Networks. Low power, high data rates and data security makes it ideal solution for medical applications. In this paper, signal attenuation for different frequencies, using FR4 electrodes, has been investigated. Performance of single and multichannel transmission with frequency modulation of analog signal has been tested. Experiment results show that HBC is a feasible solution for transmitting data between BSN nodes.

  8. Experience with Free Bodies

    NASA Technical Reports Server (NTRS)

    Butler, T. G.

    1985-01-01

    Some of the problems that confront an analyst in free body modeling, to satisfy rigid body conditions are discussed and with some remedies for these problems are presented. The problems of detecting these culprits at various levels within the analysis are examined. A new method within NASTRAN for checking the model for defects very early in the analysis without requiring the analyst to bear the expense of an eigenvalue analysis before discovering these defects is outlined.

  9. WELDED JACKETED URANIUM BODY

    DOEpatents

    Gurinsky, D.H.

    1958-08-26

    A fuel element is presented for a neutronic reactor and is comprised of a uranium body, a non-fissionable jacket surrounding sald body, thu jacket including a portion sealed by a weld, and an inclusion in said sealed jacket at said weld of a fiux having a low neutron capture cross-section. The flux is provided by combining chlorine gas and hydrogen in the intense heat of-the arc, in a "Heliarc" welding muthod, to form dry hydrochloric acid gas.

  10. Male Body Contouring.

    PubMed

    Singh, Babu; Keaney, Terrence; Rossi, Anthony M

    2015-09-01

    Men are increasingly turning to dermatologists and plastic surgeons to request procedures that correct or enhance physical features. With the advent of this emerging new patient population, alterations in preexisting aesthetic techniques, gender-specific uses of existing devices and overall approaches need to be revisited and adapted to obtain results that are suitable for the male patient. Recently, body contouring has become one of the most sought out procedures by men. Although the majority of clinical studies involving body contouring esthetics are performed with female patients, gains from such studies can be extrapolated to men. Body contouring can be broadly classified as non-invasive or invasive, depending on the modality used. Non-invasive contouring is most frequently performed with devices that target subcutaneous adipose with focused electrical or thermal energy, including low-level laser, cryolipolysis, ultrasonography, and radiofrequency. Invasive body contouring modalities useful for male body contouring include liposuction, pectoral and abdominal wall etching, jawline fillers, synthetic deoxycholic acid injections, and solid silicone implants. The purpose of this review is to bring attention to the unique aspects, strategies, and modalities used in aesthetic body contouring for the male patient.

  11. The neural basis of body form and body action agnosia.

    PubMed

    Moro, Valentina; Urgesi, Cosimo; Pernigo, Simone; Lanteri, Paola; Pazzaglia, Mariella; Aglioti, Salvatore Maria

    2008-10-23

    Visual analysis of faces and nonfacial body stimuli brings about neural activity in different cortical areas. Moreover, processing body form and body action relies on distinct neural substrates. Although brain lesion studies show specific face processing deficits, neuropsychological evidence for defective recognition of nonfacial body parts is lacking. By combining psychophysics studies with lesion-mapping techniques, we found that lesions of ventromedial, occipitotemporal areas induce face and body recognition deficits while lesions involving extrastriate body area seem causatively associated with impaired recognition of body but not of face and object stimuli. We also found that body form and body action recognition deficits can be double dissociated and are causatively associated with lesions to extrastriate body area and ventral premotor cortex, respectively. Our study reports two category-specific visual deficits, called body form and body action agnosia, and highlights their neural underpinnings.

  12. Bacterial body plans

    PubMed Central

    Rieger, Tomáš; Neubauer, Zdeněk; Blahůšková, Anna; Cvrčková, Fatima

    2008-01-01

    The bacterium Serratia marcescens produces a plethora of multicellular shapes of different colorations on solid substrates, allowing immediate visual detection of varieties. Such a plasticity allows studies on multicellular community scale spanning two extremes, from well-elaborated individual colonies to undifferentiated cell mass. For a single strain and medium, we obtained a range of different multicellular bodies, depending on the layout of initial plating. Four principal factors affecting the morphogenetic pathways of such bodies can be distinguished: (1) amount, density and distribution pattern of founder cells; (2) the configuration of surrounding free medium; (3) the presence and character of other bacterial bodies sharing the same niche; and (4) self-perception, resulting in delimitation towards other bodies. The last feature results in an ability of well-formed multicellular individuals to maintain their identity upon a close mutual contact, as well as in spontaneous separation of cell masses in experimental chimeras. We propose an “embryo-like” colony model where multicellular bacterial bodies develop along genuine ontogenetic pathways inherent to the given species (clone), while external shaping forces (like nutrient gradients, pH, etc.,) exert not formative, but only regulative roles in the process. PMID:19513204

  13. Calculate Your Body Mass Index

    MedlinePlus

    ... Can! ) Health Professional Resources Calculate Your Body Mass Index Body mass index (BMI) is a measure of body fat based ... to content Twitter Facebook YouTube Google+ SEARCH | SITE INDEX | ACCESSIBILITY | PRIVACY STATEMENT | FOIA | OIG | CONTACT US National ...

  14. Magnetic human body communication.

    PubMed

    Park, Jiwoong; Mercier, Patrick P

    2015-01-01

    This paper presents a new human body communication (HBC) technique that employs magnetic resonance for data transfer in wireless body-area networks (BANs). Unlike electric field HBC (eHBC) links, which do not necessarily travel well through many biological tissues, the proposed magnetic HBC (mHBC) link easily travels through tissue, offering significantly reduced path loss and, as a result, reduced transceiver power consumption. In this paper the proposed mHBC concept is validated via finite element method simulations and measurements. It is demonstrated that path loss across the body under various postures varies from 10-20 dB, which is significantly lower than alternative BAN techniques. PMID:26736639

  15. Inclusion Body Myositis

    PubMed Central

    Dimachkie, Mazen M.; Barohn, Richard J.

    2012-01-01

    The idiopathic inflammatory myopathies are a group of rare disorders that share many similarities. These include dermatomyositis (DM), polymyositis (PM), necrotizing myopathy (NM), and sporadic inclusion body myositis (IBM). Inclusion body myositis is the most common idiopathic inflammatory myopathy after age 50 and it presents with chronic proximal leg and distal arm asymmetric mucle weakness. Despite similarities with PM, it is likely that IBM is primarily a degenerative disorder rather than an inflammatory muscle disease. Inclusion body myositis is associated with a modest degree of creatine kinase (CK) elevation and an abnormal electromyogram demonstrating an irritative myopathy with some chronicity. The muscle histopathology demonstrates inflammatory exudates surrounding and invading nonnecrotic muscle fibers often times accompanied by rimmed vacuoles. In this chapter, we review sporadic IBM. We also examine past, essentially negative, clinical trials in IBM and review ongoing clinical trials. For further details on DM, PM, and NM, the reader is referred to the idiopathic inflammatory myopathies chapter. PMID:23117948

  16. Inclusion body myositis.

    PubMed

    Dimachkie, Mazen M; Barohn, Richard J

    2012-07-01

    The idiopathic inflammatory myopathies are a group of rare disorders that share many similarities. These include dermatomyositis (DM), polymyositis (PM), necrotizing myopathy (NM), and sporadic inclusion body myositis (IBM). Inclusion body myositis is the most common idiopathic inflammatory myopathy after age 50 and it presents with chronic proximal leg and distal arm asymmetric mucle weakness. Despite similarities with PM, it is likely that IBM is primarily a degenerative disorder rather than an inflammatory muscle disease. Inclusion body myositis is associated with a modest degree of creatine kinase (CK) elevation and an abnormal electromyogram demonstrating an irritative myopathy with some chronicity. The muscle histopathology demonstrates inflammatory exudates surrounding and invading nonnecrotic muscle fibers often times accompanied by rimmed vacuoles. In this chapter, we review sporadic IBM. We also examine past, essentially negative, clinical trials in IBM and review ongoing clinical trials. For further details on DM, PM, and NM, the reader is referred to the idiopathic inflammatory myopathies chapter.

  17. [The "invisible" foreign body].

    PubMed

    Knopf, A; Dobritz, M; Fauser, C

    2009-11-01

    A 58-year-old female patient fell down a stairs carrying a plant pot. The bamboo stem penetrated the left lower lip and remained stuck in the throat. The patient pulled the bamboo stem out immediately. The lower lip was sutured and a tear in the mucous membrane in the tonsils was explored and cleansed. A foreign body could not be detected either clinically or by computed tomography (CT) of the neck. After 1 week a control CT of the neck was carried out because the patient complained of odynophagy and a putrid taste. An initially overlooked foreign body was now detected in the "lung window" and lay in an abscess cavity on the prevertebral surface. The foreign body was surgically removed with the patient under narcosis and there were no aftereffects. PMID:19838653

  18. Body Integrity Identity Disorder

    PubMed Central

    Blom, Rianne M.; Hennekam, Raoul C.; Denys, Damiaan

    2012-01-01

    Introduction Body Integrity Identity Disorder (BIID) is a rare, infrequently studied and highly secretive condition in which there is a mismatch between the mental body image and the physical body. Subjects suffering from BIID have an intense desire to amputate a major limb or severe the spinal cord in order to become paralyzed. Aim of the study is to broaden the knowledge of BIID amongst medical professionals, by describing all who deal with BIID. Methods Somatic, psychiatric and BIID characteristic data were collected from 54 BIID individuals using a detailed questionnaire. Subsequently, data of different subtypes of BIID (i.e. wish for amputation or paralyzation) were evaluated. Finally, disruption in work, social and family life due to BIID in subjects with and without amputation were compared. Results Based on the subjects' reports we found that BIID has an onset in early childhood. The main rationale given for their desire for body modification is to feel complete or to feel satisfied inside. Somatic and severe psychiatric co-morbidity is unusual, but depressive symptoms and mood disorders can be present, possibly secondary to the enormous distress BIID puts upon a person. Amputation and paralyzation variant do not differ in any clinical variable. Surgery is found helpful in all subjects who underwent amputation and those subjects score significantly lower on a disability scale than BIID subjects without body modification. Conclusions The amputation variant and paralyzation variant of BIID are to be considered as one of the same condition. Amputation of the healthy body part appears to result in remission of BIID and an impressive improvement of quality of life. Knowledge of and respect for the desires of BIID individuals are the first steps in providing care and may decrease the huge burden they experience. PMID:22514657

  19. Asymptomatic inhaled foreign body

    PubMed Central

    Salim, Muhammad U.; Asghar, Asif; Tareen, Irum; Azhar, Muhammad

    2016-01-01

    It is very rare to have a big foreign body in the lungs without any complications or symptoms for 2 years. A 14-year-old male with episodes of minor hemoptysis for 4 weeks had a history of inhalation of a bullet 2 years earlier. He had asymptomatic for lung complications for 2 years. The bullet was removed by right thoracotomy and non-anatomical wedge stapled resection, and he followed an uneventful recovery. An aspirated foreign body although big can remain asymptomatic for a long time, especially if it has migrated to the periphery. PMID:27652366

  20. Very Young Children's Body Image: Bodies and Minds under Construction

    ERIC Educational Resources Information Center

    Birbeck, David; Drummond, Murray

    2006-01-01

    In recent years research has recognised that notions of body image, body image ideals and body dissatisfaction develop much earlier than was once thought. Forty-seven children (25 male; 22 female) aged between 5 and 6 years were interviewed on three occasions over 12 months regarding their perceptions of body image. The interviews revealed…

  1. World Ethics Body Proposed

    ERIC Educational Resources Information Center

    Holden, Constance

    1972-01-01

    Outlines the main features and areas of responsibility of an international, non-governmental body proposed by the Council for International Organizations of Medical Sciences to explore the moral and social issues raised by recent and impending developments in biology and medicine. (AL)

  2. Body Mass Index

    PubMed Central

    Nuttall, Frank Q.

    2015-01-01

    The body mass index (BMI) is the metric currently in use for defining anthropometric height/weight characteristics in adults and for classifying (categorizing) them into groups. The common interpretation is that it represents an index of an individual’s fatness. It also is widely used as a risk factor for the development of or the prevalence of several health issues. In addition, it is widely used in determining public health policies.The BMI has been useful in population-based studies by virtue of its wide acceptance in defining specific categories of body mass as a health issue. However, it is increasingly clear that BMI is a rather poor indicator of percent of body fat. Importantly, the BMI also does not capture information on the mass of fat in different body sites. The latter is related not only to untoward health issues but to social issues as well. Lastly, current evidence indicates there is a wide range of BMIs over which mortality risk is modest, and this is age related. All of these issues are discussed in this brief review. PMID:27340299

  3. Automotive Body Repair Competencies.

    ERIC Educational Resources Information Center

    D'Armond, Jack; And Others

    Designed to provide a model curriculum and guidelines, this manual presents tasks that were identified by employers, employees, and teachers as important in a postsecondary auto body repair curriculum. The tasks are divided into ten major component areas of instruction: metalworking and fiberglass, painting, frame and suspension, glass and trim,…

  4. Marijuana and Body Weight

    PubMed Central

    Sansone, Lori A.

    2014-01-01

    Acute marijuana use is classically associated with snacking behavior (colloquially referred to as “the munchies”). In support of these acute appetite-enhancing effects, several authorities report that marijuana may increase body mass index in patients suffering from human immunodeficiency virus and cancer. However, for these medical conditions, while appetite may be stimulated, some studies indicate that weight gain is not always clinically meaningful. In addition, in a study of cancer patients in which weight gain did occur, it was less than the comparator drug (megestrol). However, data generally suggest that acute marijuana use stimulates appetite, and that marijuana use may stimulate appetite in low-weight individuals. As for large epidemiological studies in the general population, findings consistently indicate that users of marijuana tend to have lower body mass indices than nonusers. While paradoxical and somewhat perplexing, these findings may be explained by various study confounds, such as potential differences between acute versus chronic marijuana use; the tendency for marijuana use to be associated with other types of drug use; and/or the possible competition between food and drugs for the same reward sites in the brain. Likewise, perhaps the effects of marijuana are a function of initial weight status—i.e., maybe marijuana is a metabolic regulatory substance that increases body weight in low-weight individuals but not in normal-weight or overweight individuals. Only further research will clarify the complex relationships between marijuana and body weight. PMID:25337447

  5. Body Odor (For Girls)

    MedlinePlus

    ... drink more water? Yes! When you sweat, your body loses water. If you lose too much water, you can ... around your vaginal area with mild soap and water and changing your underwear regularly is usually ... Related Content Puberty What does it ...

  6. Understanding Body Language.

    ERIC Educational Resources Information Center

    Sielski, Lester M.

    1979-01-01

    The article details the significance of nonverbal communication or body language for the counselor in interview situations. It gives background material of the research done in the area of nonverbal communication, and quotes extensively from the leaders in the field. (Author)

  7. Lewy body dementias.

    PubMed

    Walker, Zuzana; Possin, Katherine L; Boeve, Bradley F; Aarsland, Dag

    2015-10-24

    The broad importance of dementia is undisputed, with Alzheimer's disease justifiably getting the most attention. However, dementia with Lewy bodies and Parkinson's disease dementia, now called Lewy body dementias, are the second most common type of degenerative dementia in patients older than 65 years. Despite this, Lewy body dementias receive little attention and patients are often misdiagnosed, leading to less than ideal management. Over the past 10 years, considerable effort has gone into improving diagnostic accuracy by refining diagnostic criteria and using imaging and other biomarkers. Dementia with Lewy bodies and Parkinson's disease dementia share the same pathophysiology, and effective treatments will depend not only on successful treatment of symptoms but also on targeting the pathological mechanisms of disease, ideally before symptoms and clinical signs develop. We summarise the most pertinent progress from the past 10 years, outlining some of the challenges for the future, which will require refinement of diagnosis and clarification of the pathogenesis, leading to disease-modifying treatments. PMID:26595642

  8. Computed body tomography.

    PubMed

    Alfidi, R J; Haaga, J R

    1976-12-01

    Only the surface of the diagnostic possibilities inherent in CT imaging has been scratched. Solic organ pathology is readily visible in most instances by computed tomography. With further extension of present knowledge and development of newer contrast agents, the ability of computed body tomography to image a wide range of diseases appears almost limitless.

  9. Porous metallic bodies

    DOEpatents

    Landingham, R.L.

    1984-03-13

    Porous metallic bodies having a substantially uniform pore size of less than about 200 microns and a density of less than about 25 percent theoretical, as well as the method for making them, are disclosed. Group IIA, IIIB, IVB, VB, and rare earth metal hydrides a

  10. Weightlessness and Free Bodies.

    ERIC Educational Resources Information Center

    Easton, D.

    1983-01-01

    Provides additional information on a demonstration described in the March 1981 issue of "The Physics Teacher" involving free-falling objects using styrofoam cups, rubber bands, and weights. Approaches the subject using free-body diagrams (included) and discusses the mechanism by which the weights are pulled into the cup. (JM)

  11. Body inversion effect without body sense: insights from deafferentation.

    PubMed

    Bosbach, Simone; Knoblich, Guenther; Reed, Catherine L; Cole, Jonathan; Prinz, Wolfgang

    2006-01-01

    Like faces, human bodies are recognized via the configuration of their parts; their recognition is impaired by inversion. Processing of configural relations has been shown to depend on perceptual expertise with certain classes of objects. Because people see their own body and others' bodies frequently, humans are experts in the visual processing of human body postures. In addition, the observer's own on-line, multimodal body representation which heavily relies on current proprioception may play a crucial role in recognizing human body postures. We investigated whether static body posture recognition relied on current proprioceptive inputs or whether visual familiarity and stored body representations were sufficient. IW, who is deafferented (lost cutaneous touch and proprioception from his body), was tested on the recognition of upright and inverted human body postures, faces, and houses. As controls, IW showed an inversion effect for abstract, common, and rare human body postures as well as faces, but not houses. Results rule out a strong contribution of current afferent inputs to the recognition of human postures. The findings are discussed in terms of the role of the body schema in body posture recognition and how other contributions from one's own body may be involved in the visual processing of human bodies.

  12. Early Adolescence: Whole Body Learning.

    ERIC Educational Resources Information Center

    Cannon, Roger K., Jr.; Padilla, Michael J.

    1982-01-01

    "Whole body" denotes using the entire body to sense and experience a concept or idea. Typical whole body learning activities involve use of several senses: muscle sense, temperature, pain, pressure, and sense of equilibrium. Four whole body science activities are described, including identifying trees by touch. (Author/JN)

  13. Body Art: A Panel Discussion.

    ERIC Educational Resources Information Center

    Surgenor, Peter; And Others

    1997-01-01

    Three camp directors discuss their policies regarding body art and body piercing. Only one director reported a strict policy prohibiting tattoos or body art based on standards that the camp portrays to families. However, all directors enforced policies prohibiting clothing or body art that mentions alcohol, tobacco, drug use, or inappropriate…

  14. Body image inflexibility mediates the relationship between body image evaluation and maladaptive body image coping strategies.

    PubMed

    Mancuso, Serafino G

    2016-03-01

    Body image inflexibility, the unwillingness to experience negative appearance-related thoughts and emotions, is associated with negative body image and eating disorder symptoms. The present study investigated whether body image inflexibility mediated the relationship between body image evaluation and maladaptive body image coping strategies (appearance-fixing and experiential avoidance) in a college and community sample comprising 156 females aged 18-51 years (M=22.76, SD=6.96). Controlling for recruitment source (college vs. community), body image inflexibility fully mediated the relationship between body image evaluation and maladaptive body image coping strategies. Results indicated that an unwillingness to experience negative appearance-related thoughts and emotions is likely responsible for negative body image evaluation's relationship to appearance-fixing behaviours and experiential avoidance. Findings support extant evidence that interventions that explicitly target body image inflexibility, such as Acceptance and Commitment Therapy, may have utility in treating body dissatisfaction in nonclinical populations. PMID:26595857

  15. Body image inflexibility mediates the relationship between body image evaluation and maladaptive body image coping strategies.

    PubMed

    Mancuso, Serafino G

    2016-03-01

    Body image inflexibility, the unwillingness to experience negative appearance-related thoughts and emotions, is associated with negative body image and eating disorder symptoms. The present study investigated whether body image inflexibility mediated the relationship between body image evaluation and maladaptive body image coping strategies (appearance-fixing and experiential avoidance) in a college and community sample comprising 156 females aged 18-51 years (M=22.76, SD=6.96). Controlling for recruitment source (college vs. community), body image inflexibility fully mediated the relationship between body image evaluation and maladaptive body image coping strategies. Results indicated that an unwillingness to experience negative appearance-related thoughts and emotions is likely responsible for negative body image evaluation's relationship to appearance-fixing behaviours and experiential avoidance. Findings support extant evidence that interventions that explicitly target body image inflexibility, such as Acceptance and Commitment Therapy, may have utility in treating body dissatisfaction in nonclinical populations.

  16. Body composition in detoxified alcoholics.

    PubMed

    York, J L; Pendergast, D E

    1990-04-01

    Body composition was evaluated in healthy detoxified alcoholics (aged 20-39) and lifestyle controls, with the expectation that prolonged, excessive consumption of alcohol may bring about nutritional or toxicologic alterations in the relationship between body fat and lean body mass. Body fat was assessed by measurements of skin-fold thickness and by means of bioelectric impedance methodology. No noteworthy differences were observed between alcoholics and controls with regard to the relationship between lean body mass and body fat or in the relationship between extracellular and intracellular water. It would appear that 15-20 years of heavy alcohol consumption does not necessarily alter body composition in healthy, young alcoholics.

  17. Full body restraint system

    NASA Technical Reports Server (NTRS)

    Ryder, Susan (Inventor)

    1990-01-01

    A body restraint system (30) allows the user's body (10) to be in the zero gravity neutral posture. The system (30) includes a waist restraint (32) in the form of a curved, padded unit (34) containing a retractable belt (36) coiled on a spring loaded capstan (38) with a buckle (40) extending from front (42) of the unit (34). A second belt (44) is fastened around the user's waist (16). A clasp (46) is configured to engage the buckle (40). The waist restraint (32) is positioned near foot restraints (52). The foot restraints (52) have foot platforms (59) with pads (60) of a suitable two part attaching material, such as the fasteners available from Minnesota Mining and Manufacturing Company under the trademark Scotchmate Duallock. A mating pad (62) of the material is provided on soles (64) of cotton net shoes (66).

  18. Imaging body armor.

    PubMed

    Harcke, H Theodore; Schauer, David A; Harris, Robert M; Campman, Steven C; Lonergan, Gael J

    2002-04-01

    This study examined the feasibility of performing radiographic studies on patients wearing standard-issue body armor. The Kevlar helmet, fragmentation vest, demining suit sleeve, and armor plate were studied with plain film and computed tomography in a simulated casualty situation. We found that the military helmet contains metal screws and metal clips in the headband, but diagnostic computed tomographic images can be obtained. Kevlar, the principal component of soft armor, has favorable photon attenuation characteristics. Plate armor of composite material also did not limit radiographic studies. Therefore, when medically advantageous, patients can be examined radiographically while wearing standard military body armor. Civilian emergency rooms should be aware of these observations because law enforcement officers wear similar protective armor. PMID:11977874

  19. Carotid body paraganglioma.

    PubMed

    Manzoor, Tahir; Ahmed, Bashir; Najam, Atif; Ayub, Zeeshan

    2009-08-01

    Carotid body tumours are benign neoplasms. This case report describes two patients with this rare tumour with diagnostic workup and treatment options. The first case was a 36-year-old gentleman who presented with 6 months history of painless swelling on the left side of neck. The second patient was 60-years-old man who presented with slowly growing swelling on the right side of neck for the last 20 years. Both patients had transmitted pulsations over the swelling. On suspicion of a vascular lesion, a contrast enhanced CT scan and Doppler's ultrasound of neck was advised which suggested the diagnosis of a carotid body tumour. Magnetic Resonance Angiography (MRA) confirmed the diagnosis. Excision in collaboration with vascular surgeon was planned for the first case. The second case was subjected to radiation therapy due to the large size of tumour and the patient's age.

  20. Dementia with Lewy bodies

    PubMed Central

    Ferman, Tanis J.; Boeve, Bradley F.

    2009-01-01

    Synopsis The advent of new immunostains have improved our ability to detect limbic and cortical Lewy bodies, and it is now evident that Dementa with Lewy bodies (DLB) is the second most common neurodegenerative dementia, after Alzheimer’s disease (AD). Distinguishing DLB from AD has important implications for treatment, in terms of substances that may worsen symptoms (i.e., anticholinergic and certain neuroleptic medications) and those that may improve them (i.e., cholinesterase inhibitors, carbidopa-levodopa). Neurocognitive patterns, psychiatric features, extrapyramidal signs and sleep disturbance are helpful in differentiating DLB from AD early in the disease course. Differences in the severity of cholinergic depletion as well as type and distribution of neuropathology contribute to these clinical differences, though DLB patients with a high density of co-occuring AD pathology are less clinical distinguishable from AD. PMID:17659188

  1. SHAPED FISSIONABLE METAL BODIES

    DOEpatents

    Wigner, E.P.; Williamson, R.R.; Young, G.J.

    1958-10-14

    A technique is presented for grooving the surface of fissionable fuel elements so that expansion can take place without damage to the interior structure of the fuel element. The fissionable body tends to develop internal stressing when it is heated internally by the operation of the nuclear reactor and at the same time is subjected to surface cooling by the circulating coolant. By producing a grooved or waffle-like surface texture, the annular lines of tension stress are disrupted at equally spaced intervals by the grooves, thereby relieving the tension stresses in the outer portions of the body while also facilitating the removal of accumulated heat from the interior portion of the fuel element.

  2. N-body models

    NASA Technical Reports Server (NTRS)

    Miller, R. H.

    1990-01-01

    The experimental discovery of an overstability in the central regions of galaxies is briefly discussed, and numerical methods for integrating orbits are briefly addressed. The overstability manifests itself as a growing amplitude in the orbit of a galaxy's nucleus about its mass centroid. This finding may complicate studies of the topological properties of orbits and studies of the bifurcation structure of orbits. A sample problem is used to illustrate the importance of a Liouville theorem in N-body calculations.

  3. [Body-contouring surgery].

    PubMed

    Pitanguy, Ivo

    2003-01-01

    Concepts of beauty have been continuously evolving throughout the history of mankind. The voluptuous figures that were idealized by artists in the past have been substituted by slimmer forms. Medical advances in this century have permitted safe and efficient surgical correction of contour deformities. Until recently, these alterations were mostly hidden under heavy clothing or were reluctantly accepted. Current fashion trends generally promote body-revealing attire. The media frequently encourages the importance of fitness and good health linking these qualities with youthfulness and beauty. The subliminal as well as overt message is that these are necessary and desirable requirements for social acceptance and professional success. On the other hand, current sedentary lifestyle and dietary excesses, associated with factors such as genetic determination, pregnancy and the aging process, contribute to alterations of body contour that result in the loss of the individual's body image. This creates a strong psychological motivation for surgical correction. Localized fat deposits and skin flaccidity are sometimes resistant to the most sincere efforts in weight loss and sport activities. This ever-increasing request for contour surgery has been favorably met by safe and effective anesthesiology as well as efficient surgical techniques, resulting in a high degree of patient satisfaction. It is essential that today's aesthetic surgeon understand the motivations of patients who present with body contour deformities. A request for surgical treatment should be seen as a legitimate desire to achieve a physical form that approximates the individual with his or her ideal self-image. Additionally, the surgeon must always consider the possible benefit of including the participation of a multidisciplinary team approach. Depending on each case, this team should include consultants in endocrinology, dermatology, oculoplastics, pediatrics and other appropriate specialties.

  4. Schlemm, the body snatcher?

    PubMed

    Winkelmann, Andreas

    2008-01-01

    Friedrich Schlemm (1795-1858) is well known for his original description of the scleral venous sinus, known since as Schlemm's canal. He grew up in a village in the Duchy of Braunschweig (Brunswick). As his family could not afford higher education, he was apprenticed to a barber-surgeon in Braunschweig. This gave him the opportunity to study anatomy and surgery at the local Anatomico-Surgical Institute. Recently discovered archival sources demonstrate that, in June of 1816, Schlemm and a fellow student disinterred the body of a deceased woman late at night in a Braunschweig churchyard to bring the body to this Institute and study the effects of rickets on the woman's bones. They were caught and sentenced to 4 weeks of prison. Subsequently, Schlemm left Braunschweig and found work as a low-rank army surgeon in Berlin. Professor Rudolphi, the director of the Berlin Institute of Anatomy, took note of Schlemm's manual dexterity in anatomical dissection and supported his impressive career. Schlemm eventually became full professor of anatomy in 1833 and spent his remaining 25 years in Berlin with a focus on teaching students and training surgeons. As historical background information is largely lacking in this regard, it is impossible to decide whether Schlemm's episode of grave robbing was a solitary instance or a more common method of acquiring bodies for anatomical instruction in early 19th century Germany. PMID:18396022

  5. Immunization alters body odor.

    PubMed

    Kimball, Bruce A; Opiekun, Maryanne; Yamazaki, Kunio; Beauchamp, Gary K

    2014-04-10

    Infections have been shown to alter body odor. Because immune activation accompanies both infection and immunization, we tested the hypothesis that classical immunization might similarly result in the alteration of body odors detectable by trained biosensor mice. Using a Y-maze, we trained biosensor mice to distinguish between urine odors from rabies-vaccinated (RV) and unvaccinated control mice. RV-trained mice generalized this training to mice immunized with the equine West Nile virus (WNV) vaccine compared with urine of corresponding controls. These results suggest that there are similarities between body odors of mice immunized with these two vaccines. This conclusion was reinforced when mice could not be trained to directly discriminate between urine odors of RV- versus WNV-treated mice. Next, we trained biosensor mice to discriminate the urine odors of mice treated with lipopolysaccharide (LPS; a general elicitor of innate immunological responses) from the urine of control mice. These LPS-trained biosensors could distinguish between the odors of LPS-treated mouse urine and RV-treated mouse urine. Finally, biosensor mice trained to distinguish between the odors of RV-treated mouse urine and control mouse urine did not generalize this training to discriminate between the odors of LPS-treated mouse urine and control mouse urine. From these experiments, we conclude that: (1) immunization alters urine odor in similar ways for RV and WNV immunizations; and (2) immune activation with LPS also alters urine odor but in ways different from those of RV and WNV. PMID:24524972

  6. Body as subject1

    PubMed Central

    MEIR, IRIT; PADDEN, CAROL A.; ARONOFF, MARK; SANDLER, WENDY

    2011-01-01

    The notion of subject in human language has a privileged status relative to other arguments. This special status is manifested in the behavior of subjects at the morphological, syntactic, semantic and discourse levels. Here we bring evidence that subjects have privileged status at the lexical level as well, by analyzing lexicalization patterns of verbs in three different sign languages. Our analysis shows that the sublexical structure of iconic signs denoting state of affairs in these languages manifests an inherent pattern of form–meaning correspondence: the signer’s body consistently represents one argument of the verb, the subject. The hands, moving in relation to the body, represent all other components of the event – including all other arguments. This analysis shows that sign languages provide novel evidence in support of the centrality of the notion of subject in human language. It also solves a typological puzzle about the apparent primacy of object in sign language verb agreement, a primacy not usually found in spoken languages, in which subject agreement ranks higher. Our analysis suggests that the subject argument is represented by the body and is part of the lexical structure of the verb. Because it is always inherently represented in the structure of the sign, the subject is more basic than the object, and tolerates the omission of agreement morphology. PMID:23066169

  7. Few-body physics

    SciTech Connect

    Briceno, Raul

    2015-05-01

    Few-body hadronic observables play an essential role in a wide number of processes relevant for both particle and nuclear physics. In order for Lattice QCD to offer insight into the interpretation of few-body states, a theoretical infrastructure must be developed to map Euclidean-time correlation functions to the desired Minkowski-time few-body observables. In this talk, I will first review the formal challenges associated with the studies of such systems via Lattice QCD, as first introduced by Maiani and Testa, and then review methodology to circumvent said limitations. The first main example of the latter is the formalism of Luscher to analyze elastic scattering and a second is the method of Lellouch & Luscher to analyze weak decays. I will then proceed to discus recent theoretical generalizations of these frameworks that allow for the determination of scattering amplitudes, resonances, transition and elastic form factors. Finally, I will outline outstanding problems, including those that are now beginning to be addressed.

  8. Implicit beliefs about ideal body image predict body image dissatisfaction

    PubMed Central

    Heider, Niclas; Spruyt, Adriaan; De Houwer, Jan

    2015-01-01

    We examined whether implicit measures of actual and ideal body image can be used to predict body dissatisfaction in young female adults. Participants completed two Implicit Relational Assessment Procedures (IRAPs) to examine their implicit beliefs concerning actual (e.g., I am thin) and desired ideal body image (e.g., I want to be thin). Body dissatisfaction was examined via self-report questionnaires and rating scales. As expected, differences in body dissatisfaction exerted a differential influence on the two IRAP scores. Specifically, the implicit belief that one is thin was lower in participants who exhibited a high degree of body dissatisfaction than in participants who exhibited a low degree of body dissatisfaction. In contrast, the implicit desire to be thin (i.e., thin ideal body image) was stronger in participants who exhibited a high level of body dissatisfaction than in participants who were less dissatisfied with their body. Adding further weight to the idea that both IRAP measures captured different underlying constructs, we also observed that they correlated differently with body mass index, explicit body dissatisfaction, and explicit measures of actual and ideal body image. More generally, these findings underscore the advantage of using implicit measures that incorporate relational information relative to implicit measures that allow for an assessment of associative relations only. PMID:26500567

  9. Rotor/body aerodynamic interactions

    NASA Technical Reports Server (NTRS)

    Betzina, M. D.; Smith, C. A.; Shinoda, P.

    1983-01-01

    A wind tunnel investigation was conducted in which independent, steady state aerodynamic forces and moments were measured on a 2.24 m diam. two bladed helicopter rotor and on several different bodies. The mutual interaction effects for variations in velocity, thrust, tip-path-plane angle of attack, body angle of attack, rotor/body position, and body geometry were determined. The results show that the body longitudinal aerodynamic characteristics are significantly affected by the presence of a rotor and hub, and that the hub interference may be a major part of such interaction. The effects of the body on the rotor performance are presented.

  10. Rotor/body aerodynamic interactions

    NASA Technical Reports Server (NTRS)

    Betzina, M. D.; Smith, C. A.; Shinoda, P.

    1985-01-01

    A wind tunnel investigation was conducted in which independent, steady state aerodynamic forces and moments were measured on a 2.24 m diam. two bladed helicopter rotor and on several different bodies. The mutual interaction effects for variations in velocity, thrust, tip-path-plane angle of attack, body angle of attack, rotor/body position, and body geometry were determined. The results show that the body longitudinal aerodynamic characteristics are significantly affected by the presence of a rotor and hub, and that the hub interference may be a major part of such interaction. The effects of the body on the rotor performance are presented.

  11. Distance to Dark Bodies

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Using the unique orbit of NASA's Spitzer Space Telescope and a depth-perceiving trick called parallax, astronomers have determined the distance to an invisible Milky Way object called OGLE-2005-SMC-001. This artist's concept illustrates how this trick works: different views from both Spitzer and telescopes on Earth are combined to give depth perception.

    Our Milky Way galaxy is heavier than it looks, and scientists use the term 'dark matter' to describe all the 'heavy stuff' in the universe that seems to be present but invisible to our telescopes. While much of this dark matter is likely made up of exotic materials, different from the ordinary particles that make up the world around us, some may consist of dark celestial bodies -- like planets, black holes, or failed stars -- that do not produce light or are too faint to detect from Earth. OGLE-2005-SMC-001 is one of these dark celestial bodies.

    Although astronomers cannot see a dark body, they can sense its presence from the way light acts around it. When a dark body like OGLE-2005-SMC-001 passes in front of a bright star, its gravity causes the background starlight to bend and brighten, a process called gravitational microlensing. When the observing telescope, dark body, and star system are closely aligned, the microlensing event reaches maximum, or peak, brightness.

    A team of astronomers first sensed OGLE-2005-SMC-001's presence when it passed in front of a star in a neighboring satellite galaxy called the Small Magellanic Cloud. In this artist's rendering, the satellite galaxy is depicted as the fuzzy structure sitting to the left of Earth. Once they detected this microlensing event, the scientists used Spitzer and the principle of parallax to figure out its distance. Humans naturally use parallax to determine distance. Each eye sees the distance of an object differently. The brain takes each eye's perspective and instantaneously calculates how far away the object is.

    To determine OGLE

  12. VIEW OF A BODY COUNTING ROOM IN BUILDING 122. BODY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF A BODY COUNTING ROOM IN BUILDING 122. BODY COUNTING MEASURES RADIOACTIVE MATERIAL IN THE BODY. DESIGNED TO MINIMIZE EXTERNAL SOURCES OF RADIATION, BODY COUNTING ROOMS ARE CONSTRUCTED OF PRE-WORLD WAR II (WWII) STEEL. PRE-WWII STEEL, WHICH HAS NOT BEEN AFFECTED BY NUCLEAR FALLOUT, IS LOWER IS RADIOACTIVITY THAN STEEL CREATED AFTER WWII. (10/25/85) - Rocky Flats Plant, Emergency Medical Services Facility, Southwest corner of Central & Third Avenues, Golden, Jefferson County, CO

  13. Agricultural Body-Building: Incorporations of Gender, Body and Work

    ERIC Educational Resources Information Center

    Brandth, Berit

    2006-01-01

    This paper is concerned with gendered embodiment of agricultural work, particularly the connection between women's gender identity and the body at work. Focussing on how the body enters into relations with the tools of work, four processes are identified by which women's bodies, work and machinery are incorporated into each other and give each…

  14. Body Build Satisfaction and the Congruency of Body Build Perceptions.

    ERIC Educational Resources Information Center

    Hankins, Norman E.; Bailey, Roger C.

    1979-01-01

    Females were administered the somatotype rating scale. Satisfied subjects showed greater congruency between their own and wished-for body build, and greater congruency between their own and friend/date body builds, but less congruency between their own body build and the female stereotype. (Author/BEF)

  15. Two-Body and Three-Body Atomic Recombination Reactions.

    ERIC Educational Resources Information Center

    Alvarino, Jose M.; Martinez, E.

    1983-01-01

    Discusses how, in some circumstances, a two-body reaction (association in absence of a third body) is the only possible association, and how reactions proceed in this case. Taking competition between two/three-body reactions into account, considers relative importance of such combinations and conditions under which the former can be competitive.…

  16. Body shape preferences: associations with rater body shape and sociosexuality.

    PubMed

    Price, Michael E; Pound, Nicholas; Dunn, James; Hopkins, Sian; Kang, Jinsheng

    2013-01-01

    There is accumulating evidence of condition-dependent mate choice in many species, that is, individual preferences varying in strength according to the condition of the chooser. In humans, for example, people with more attractive faces/bodies, and who are higher in sociosexuality, exhibit stronger preferences for attractive traits in opposite-sex faces/bodies. However, previous studies have tended to use only relatively simple, isolated measures of rater attractiveness. Here we use 3D body scanning technology to examine associations between strength of rater preferences for attractive traits in opposite-sex bodies, and raters' body shape, self-perceived attractiveness, and sociosexuality. For 118 raters and 80 stimuli models, we used a 3D scanner to extract body measurements associated with attractiveness (male waist-chest ratio [WCR], female waist-hip ratio [WHR], and volume-height index [VHI] in both sexes) and also measured rater self-perceived attractiveness and sociosexuality. As expected, WHR and VHI were important predictors of female body attractiveness, while WCR and VHI were important predictors of male body attractiveness. Results indicated that male rater sociosexuality scores were positively associated with strength of preference for attractive (low) VHI and attractive (low) WHR in female bodies. Moreover, male rater self-perceived attractiveness was positively associated with strength of preference for low VHI in female bodies. The only evidence of condition-dependent preferences in females was a positive association between attractive VHI in female raters and preferences for attractive (low) WCR in male bodies. No other significant associations were observed in either sex between aspects of rater body shape and strength of preferences for attractive opposite-sex body traits. These results suggest that among male raters, rater self-perceived attractiveness and sociosexuality are important predictors of preference strength for attractive opposite

  17. Scaling body size fluctuations

    PubMed Central

    Giometto, Andrea; Altermatt, Florian; Carrara, Francesco; Maritan, Amos; Rinaldo, Andrea

    2013-01-01

    The size of an organism matters for its metabolic, growth, mortality, and other vital rates. Scale-free community size spectra (i.e., size distributions regardless of species) are routinely observed in natural ecosystems and are the product of intra- and interspecies regulation of the relative abundance of organisms of different sizes. Intra- and interspecies distributions of body sizes are thus major determinants of ecosystems’ structure and function. We show experimentally that single-species mass distributions of unicellular eukaryotes covering different phyla exhibit both characteristic sizes and universal features over more than four orders of magnitude in mass. Remarkably, we find that the mean size of a species is sufficient to characterize its size distribution fully and that the latter has a universal form across all species. We show that an analytical physiological model accounts for the observed universality, which can be synthesized in a log-normal form for the intraspecies size distributions. We also propose how ecological and physiological processes should interact to produce scale-invariant community size spectra and discuss the implications of our results on allometric scaling laws involving body mass. PMID:23487793

  18. Porous metallic bodies

    DOEpatents

    Landingham, Richard L.

    1985-01-01

    Porous metallic bodies having a substantially uniform pore size of less than about 200 microns and a density of less than about 25 percent theoretical, as well as the method for making them, are disclosed. Group IIA, IIIB, IVB, VB, and rare earth metal hydrides are heated in a confining container at a controlled rate to a temperature of about greater than the temperature at which the hydride decomposes. Hydrogen is removed from the container and the remaining metal is heated during a second stage to a temperature greater than the temperature at which it was previously heated but not greater than the temperature of 1/2 to 2/3 the temperature at which the metal melts at a controlled rate. The resulting porous metallic body produced has a density less than about 25 percent theoretical and a pore size of less than about 200 microns. The metallic particles of the present invention have high inner surface area and possess minimum resistance to gas flow.

  19. Help! Is This My Body?

    MedlinePlus

    ... for Parents for Kids for Teens Teens Home Body Mind Sexual Health Food & Fitness Diseases & Conditions Infections Q& ... twenties are (yet again) a time when the body and mind take another step in maturing and changing. For ...

  20. Inclusion-Body Myositis: Diagnosis

    MedlinePlus

    ... How to Get Involved Donate Inclusion-Body Myositis (IBM) Share print email share facebook twitter google plus ... Causes/Inheritance Medical Management Research Inclusion-Body Myositis (IBM) News Gene Therapy Success in IBM- A Quest ...

  1. Symptoms of Lewy Body Dementia

    MedlinePlus

    ... of the environment or personal interactions, and the natural progression of the disease. All Rights Reserved Lewy Body Dementia Association, Inc. 912 Killian Hill Road S.W., Lilburn, GA 30047 © 2016 Lewy Body Dementia Association, Inc. Connect ...

  2. R-body-producing bacteria.

    PubMed

    Pond, F R; Gibson, I; Lalucat, J; Quackenbush, R L

    1989-03-01

    Until 10 years ago, R bodies were known only as diagnostic features by which endosymbionts of paramecia were identified as kappa particles. They were thought to be limited to the cytoplasm of two species in the Paramecium aurelia species complex. Now, R bodies have been found in free-living bacteria and other Paramecium species. The organisms now known to form R bodies include the cytoplasmic kappa endosymbionts of P. biaurelia and P. tetraurelia, the macronuclear kappa endosymbionts of P. caudatum, Pseudomonas avenae (a free-living plant pathogen), Pseudomonas taeniospiralis (a hydrogen-oxidizing soil microorganism), Rhodospirillum centenum (a photosynthetic bacterium), and a soil bacterium, EPS-5028, which is probably a pseudomonad. R bodies themselves fall into five distinct groups, distinguished by size, the morphology of the R-body ribbons, and the unrolling behavior of wound R bodies. In recent years, the inherent difficulties in studying the organization and assembly of R bodies by the obligate endosymbiont kappa, have been alleviated by cloning and expressing genetic determinants for these R bodies (type 51) in Escherichia coli. Type 51 R-body synthesis requires three low-molecular-mass polypeptides. One of these is modified posttranslationally, giving rise to 12 polypeptide species, which are the major structural subunits of the R body. R bodies are encoded in kappa species by extrachromosomal elements. Type 51 R bodies, produced in Caedibacter taeniospiralis, are encoded by a plasmid, whereas bacteriophage genomes probably control R-body synthesis in other kappa species. However, there is no evidence that either bacteriophages or plasmids are present in P. avenae or P. taeniospiralis. No sequence homology was detected between type 51 R-body-encoding DNA and DNA from any R-body-producing species, except C. varicaedens 1038. The evolutionary relatedness of different types of R bodies remains unknown. PMID:2651865

  3. Blending in with the Body.

    ERIC Educational Resources Information Center

    Lewis, Andrew L.; Driver, Mike

    2002-01-01

    Explains the basics of the biocompatibility of products that are used to replace body parts and mimic the biology of the human body. Describes where phosphorylcholine coating technology is used commercially in the body and discuses the use of phosphorylcholine in lenses and blood. (Contains 12 references.) (YDS)

  4. Moments of Cambered Round Bodies

    NASA Technical Reports Server (NTRS)

    Kempf, Gunther

    1949-01-01

    Results are presented for the moments and position of force centers of a series of cambered round bodies derived from a torpedo-like body of revolution. The effects of placing fins on the rear of the body of revolution are also included.

  5. Exploring Feminist Women's Body Consciousness

    ERIC Educational Resources Information Center

    Rubin, Lisa R.; Nemeroff, Carol J.; Russo, Nancy Felipe

    2004-01-01

    In a qualitative investigation of young feminists' experience of body consciousness, 25 feminist women each participated in one of 6 focus groups examining the ways they experienced body image and negotiated cultural messages about women's appearance. Participants described their experience with objectification and its impact on their body image,…

  6. Body metaphors--reading the body in contemporary culture.

    PubMed

    Skara, Danica

    2004-01-01

    This paper addresses the linguistic reframing of the human body in contemporary culture. Our aim is to provide a linguistic description of the ways in which the body is represented in modern English language. First, we will try to focus on body metaphors in general. We have collected a sample of 300 words and phrases functioning as body metaphors in modern English language. Reading the symbolism of the body we are witnessing changes in the basic metaphorical structuring of the human body. The results show that new vocabulary binds different fields of knowledge associated with machines and human beings according to a shared textual frame: human as computer and computer as human metaphor. Humans are almost blended with computers and vice versa. This metaphorical use of the human body and its parts reveals not only currents of unconscious though but also the structures of modern society and culture.

  7. [Dementia with Lewy bodies].

    PubMed

    Orimo, Satoshi

    2016-03-01

    It is important to differentiate dementia with Lewy bodies (DLB) and other dementia, especially Alzheimer disease (AD), because the medical treatment, management, and the prognosis of these diseases are different. In regard to clinical features, DLB patients have relatively mild memory disturbance, fluctuating cognition, more severe disturbances of attention, executive function, visuospacial function, visual hallucination, depression, autonomic symptoms, REM sleep behavior disorder, and idiopathic parkinsonism compared to AD patients. In regard to imaging tools, DLB patients have milder atrophy of medial temporal lobe by brain MRI, reduced occipital activity by SPECT or PET, reduced MIBG uptake by MIBG cardiac scintigraphy, and low dopamine transporter activity in the basal ganglia by SPECT or PET. PMID:27025091

  8. PML body meets telomere

    PubMed Central

    Chung, Inn; Osterwald, Sarah; Deeg, Katharina I.; Rippe, Karsten

    2012-01-01

    The unlimited proliferation potential of cancer cells requires the maintenance of their telomeres. This is frequently accomplished by reactivation of telomerase. However, in a significant fraction of tumors an alternative lengthening of telomeres (ALT) mechanism is active. The molecular mechanism of the ALT pathway remains elusive. In particular, the role of characteristic complexes of promyelocytic leukemia nuclear bodies (PML-NBs) with telomeres, the ALT-associated PML-NBs (APBs), is currently under investigation. Here, we review recent findings on the assembly, structure and functions of APBs. It is discussed how genomic aberrations in ALT-positive cancer cells could result in the formation of APBs and in ALT activity. We conclude that they are important functional intermediates in what is considered the canonical ALT pathway and discuss deregulations of cellular pathways that contribute to the emergence of the ALT phenotype. PMID:22572954

  9. BODY SENSING SYSTEM

    NASA Technical Reports Server (NTRS)

    Mah, Robert W. (Inventor)

    2005-01-01

    System and method for performing one or more relevant measurements at a target site in an animal body, using a probe. One or more of a group of selected internal measurements is performed at the target site, is optionally combined with one or more selected external measurements, and is optionally combined with one or more selected heuristic information items, in order to reduce to a relatively small number the probable medical conditions associated with the target site. One or more of the internal measurements is optionally used to navigate the probe to the target site. Neural net information processing is performed to provide a reduced set of probable medical conditions associated with the target site.

  10. Foreign Body Gingivitis.

    PubMed

    Koh, Richard U; Ko, Eugene; Oh, Tae-Ju; Edwards, Paul C

    2015-03-01

    Foreign body gingivitis (FBG) is a non-plaque induced chronic inflammatory process involving the marginal and/or attached gingiva. It results from the introduction of foreign particulate material, primarily dental prophylaxis paste and restorative dental materials, into the gingival tissues. Clinical presentation varies from an erythematous to vesiculoerosive-like process that may mimic a localized form of desquamative gingivitis or an erosive lichenoid process. Rarely, it may also present with a granular appearance. We describe the clinical presentation, differential diagnosis and clinical management of a 52-year-old Woman who presented with localized chronic inflammation of the maxillary anterior and left posterior gingiva secondary to the presence of foreign material.

  11. Body dysmorphic disorder

    PubMed Central

    Bjornsson, Andri S.; Didie, Elizabeth R.; Phillips, Katharine A.

    2010-01-01

    Body dysmorphic disorder (BDD) is a relatively common disorder that consists of a distressing or impairing preoccupation with imagined or slight defects in appearance. BDD is commonly considered to be an obsessivecompulsive spectrum disorder, based on similarities it has with obsessive-compulsive disorder. It is important to recognize and appropriately treat BDD, as this disorder is associated with marked impairment in psychosocial functioning, notably poor quality of life, and high suicidality rates. In this review, we provide an overview of research findings on BDD, including its epidemiology, clinical features, course of illness, comorbidity, psychosocial functioning, and suicidality We also briefly review recent research on neural substrates and cognitive processing. Finally, we discuss treatment approaches that appear efficacious for BDD, with a focus on serotonin-reuptake inhibitors and cognitive-behavioral therapy. PMID:20623926

  12. Insar of Aquatic Bodies

    NASA Astrophysics Data System (ADS)

    Tarikhi, P.

    2012-07-01

    Radar remote sensing is a new earth observation technology with promising results and future. InSAR is a sophisticated radar remote sensing technique for combining synthetic aperture radar (SAR) single look complex images to form interferogram and utilizing its phase contribution to land topography, surface movement and target velocity. In recent years considerable applications of Interferometric SAR technique have been developed. It is an established technique for precise assessment of land surface movements, and generating high quality digital elevation models (DEM) from space-borne and airborne data. InSAR is able to produce DEMs with the precision of a couple of ten meters whereas its movement map results have sub-centimeter precision. The technique has many applications in the context of earth sciences such as topographic mapping, environmental modelling, rainfall-runoff studies, landslide hazard zonation, and seismic source modelling. Nevertheless new developments are taking place in the application of InSAR for aquatic bodies. We have observed that using SAR Interferometry technique for aquatic bodies with the maximum temporal baseline of 16 seconds for image pairs shows considerable results enabling us to determine the direction of sea surface motion in a large area, estimate the sea surface fluctuations in the direction of sensor line-of-the-sight, detect wave pattern and the sea surface disturbance and whether the water motion is bulk and smooth or otherwise. This paper presents our experience and achievements on this new topic through discussing the facts and conditions for the use of InSAR technique. The method has been examined for Haiti, Dominican Republic, Western Chile and Western Turkey coast areas and inland lakes however ground truth data is needed for final verification. This technique scheduled to be applied in some other sites for which the proper data is available.

  13. [Nutrition and body weight].

    PubMed

    Gohlke, H

    2002-01-01

    Certain dietary components play a key role for the development of coronary artery disease (CAD). Complex carbohydrates lower the prevalence of CAD. Protein should provide 15% of daily calories. Populations with a high consumption of soy protein have a low coronary event rate and a high life expectancy. Soy protein has a favorable effect on LDL cholesterol, triglycerides and HDL cholesterol. Dietary cholesterol correlates with an increased incidence of CAD. Saturated fats increase cholesterol levels as well as the activity of clotting factor VII and promote progression of CAD. Mono-(MUFA) and poly-unsaturated fatty acids lower LDL-cholesterol to a similar extent. MUFA are contained in rape seed oil, olive oil and pea nut oil, but also in avocados and almonds. Omega-3-fatty acids are in fatty fish like salmon, tuna and herring and improve survival after myocardial infarction. They improve among others endothelial function (adhesion molecules). Eating 1-2 fish meals per week has a preventive effect on CAD and stroke. Dietary fiber decreases the risk for CAD up to 30% and favorably influences carbohydrate metabolism. Antioxidants have a favorable effect in their natural form (fruits and fresh vegetables). The secondary preventive effect of a mediterranean diet after myocardial infarction (probably by a combination of the above effects) has been validated. Body weight correlates with coronary risk, diabetes and use of health care resources. A reduction of body weight is best achieved by calory reduction plus an increase of physical activity. A calory-adjusted diet, low in total fat with a significant proportion of unsaturated fats and omega-3-fatty acids and rich in fiber is of great importance for primary and secondary prevention of cardiovascular diseases. Fruits, vegetables and whole grain products are important components of this diet, which lowers the coronary event rate, increases longevity and is associated with a low rate of malignancies and osteoporosis.

  14. Assessing outcomes in body contouring.

    PubMed

    Klassen, Anne F; Cano, Stefan J; Scott, Amie; Tsangaris, Elena; Pusic, Andrea L

    2014-10-01

    Patient-reported outcome (PRO) instruments are questionnaires designed to measure outcomes of importance to patients from their perspective. This article describes the methods used to develop a new PRO instrument for obese patients and patients having bariatric and cosmetic body contouring surgery. The BODY-Q is composed of 19 newly designed scales that measure: (1) appearance; (2) health-related quality of life; and (3) process of care. Recommended guidelines for PRO instrument development were followed to ensure that the BODY-Q meets requirements of regulatory bodies. The BODY-Q is currently being field-tested in an international study.

  15. CORROSION RESISTANT JACKETED METAL BODY

    DOEpatents

    Brugmann, E.W.

    1958-08-26

    S>Metal jacketed metallic bodies of the type used as feel elements fer nuclear reactors are presented. The fuel element is comprised of a plurality of jacketed cylindrical bodies joined in end to end abutting relationship. The abutting ends of the internal fissionable bodies are provided with a mating screw and thread means for joining the two together. The jacket material is of a corrosion resistant metal and overlaps the abutting ends of the internal bodies, thereby effectively sealing these bodies from contact with exteral reactive gases and liquids.

  16. Body size and work output.

    PubMed

    Satyanarayana, K; Naidu, A N; Chatterjee, B; Rao, N

    1977-03-01

    The relationship between work output and anthropometric, biochemical, and socioeconomic varables was studied in 57 male industrial workers engaged in the production of detonator fuses. These workers were studied for 3 months and their daily work output was carefully measured. Work output was measured in terms of the number of fuses produced per day. Clinical and biochemical examination indicated that their current nutritional status was adequate. Among the parameters studied only body weight, height, and lean body weight were significantly correlated with work output. Body weight and lean body weight were significantly correlated (P less than 0.001) with work output even after removing the influence of height by partial correlation. Total daily work output was significantly higher (P less than 0.01) in those with higher body weight and lean body weight. The rate of work was also higher in the higher body weight group

  17. Body checking behaviors in men.

    PubMed

    Walker, D Catherine; Anderson, Drew A; Hildebrandt, Thomas

    2009-06-01

    Males have been facing increasing pressure from the media to attain a lean, muscular physique, and are at risk for body dissatisfaction, disturbed eating and exercise behaviors, and abuse of appearance- and performance-enhancing drugs (APEDs). The aim of the current study was to examine the relationship between body checking and mood, symptoms of muscle dysmorphia, importance of shape and weight, and APED use in undergraduate males. Body checking in males was correlated with weight and shape concern, symptoms of muscle dysmorphia, depression, negative affect, and APED use. Body checking predicted APED use and uniquely accounted for the largest amount of variance in Muscle Dysmorphic Disorder Inventory (MDDI) scores (16%). Findings support the view that body checking is an important construct in male body image, muscle dysmorphia, and body change strategies and suggest a need for further research. PMID:19482568

  18. Gonadotropin excretion and body composition.

    PubMed

    Penny, R; Goldstein, I P; Frasier, S D

    1978-02-01

    Urinary follicle stimulating hormone (FSH) and luteinizing hormone (LH) excretion was correlated with calculated total body water (TBW) and body fat (BF) in 140 normal girls and 142 normal boys, ages 3 to 16 years. In girls, there was a significant increase in gonadotropin excretion at the time of a significant increase in BF as a percent of body weight and decrease in TBW as a percent of body weight. Pubertal changes in body composition were seen in girls at the same chronological age and stage of puberty as increased gonadotropin excretion. Similar findings were observed in boys. Pubertal changes in body composition (an increase in TBW as a percent of body weight and decrease of BF as a percent of body weight) accompanied significantly increased gonadotropin excretion. Both developmental changes were seen at the same chronological age and stage of puberty. Our findings are consistent with the hypothesis that characteristic changes in body composition as well as the other hallmarks of puberty, including menarche in girls, result from increased gonadotropin and gonadal steroid secretion. They do not support the hypothesis that changes of body composition trigger increased hypothalamic function and hormone secretion leading to the subsequent events of puberty. PMID:634687

  19. Paramecium tetraurelia basal body structure.

    PubMed

    Tassin, Anne-Marie; Lemullois, Michel; Aubusson-Fleury, Anne

    2015-01-01

    Paramecium is a free-living unicellular organism, easy to cultivate, featuring ca. 4000 motile cilia emanating from longitudinal rows of basal bodies anchored in the plasma membrane. The basal body circumferential polarity is marked by the asymmetrical organization of its associated appendages. The complex basal body plus its associated rootlets forms the kinetid. Kinetids are precisely oriented within a row in correlation with the cell polarity. Basal bodies also display a proximo-distal polarity with microtubule triplets at their proximal ends, surrounding a permanent cartwheel, and microtubule doublets at the transition zone located between the basal body and the cilium. Basal bodies remain anchored at the cell surface during the whole cell cycle. On the opposite to metazoan, there is no centriolar stage and new basal bodies develop anteriorly and at right angle from the base of the docked ones. Ciliogenesis follows a specific temporal pattern during the cell cycle and both unciliated and ciliated docked basal bodies can be observed in the same cell. The transition zone is particularly well organized with three distinct plates and a maturation of its structure is observed during the growth of the cilium. Transcriptomic and proteomic analyses have been performed in different organisms including Paramecium to understand the ciliogenesis process. The data have incremented a multi-organism database, dedicated to proteins involved in the biogenesis, composition and function of centrosomes, basal bodies or cilia. Thanks to its thousands of basal bodies and the well-known choreography of their duplication during the cell cycle, Paramecium has allowed pioneer studies focusing on the structural and functional processes underlying basal body duplication. Proteins involved in basal body anchoring are sequentially recruited to assemble the transition zone thus indicating that the anchoring process parallels the structural differentiation of the transition zone. This feature

  20. The relation between body semantics and spatial body representations.

    PubMed

    van Elk, Michiel; Blanke, Olaf

    2011-11-01

    The present study addressed the relation between body semantics (i.e. semantic knowledge about the human body) and spatial body representations, by presenting participants with word pairs, one below the other, referring to body parts. The spatial position of the word pairs could be congruent (e.g. EYE / MOUTH) or incongruent (MOUTH / EYE) with respect to the spatial position of the words' referents. In addition, the spatial distance between the words' referents was varied, resulting in word pairs referring to body parts that are close (e.g. EYE / MOUTH) or far in space (e.g. EYE / FOOT). A spatial congruency effect was observed when subjects made an iconicity judgment (Experiments 2 and 3) but not when making a semantic relatedness judgment (Experiment 1). In addition, when making a semantic relatedness judgment (Experiment 1) reaction times increased with increased distance between the body parts but when making an iconicity judgment (Experiments 2 and 3) reaction times decreased with increased distance. These findings suggest that the processing of body-semantics results in the activation of a detailed visuo-spatial body representation that is modulated by the specific task requirements. We discuss these new data with respect to theories of embodied cognition and body semantics.

  1. Inclusion Body Myositis

    PubMed Central

    Barohn, Richard J.

    2014-01-01

    The idiopathic inflammatory myopathies (IIM) are a heterogenous group of rare disorders that share many similarities. In addition to sporadic inclusion body myositis (IBM), these include dematomyositis (DM), polymyositis (PM), and autoimmune necrotizing myopathy (NM). For discussion of later three disorders, the reader is referred to the IIM review in this issue. IBM is the most common IIM after age 50. It typically presents with chronic insidious proximal leg and/or distal arm asymmetric muscle weakness leading to recurrent falls and loss of dexterity. Creatine kinase (CK) is up to 15 times elevated in IBM and needle electromyograhy (EMG) mostly shows a chronic irritative myopathy. Muscle histopathology demonstrates endomysial inflammatory exudates surrounding and invading non-necrotic muscle fibers often times accompanied by rimmed vacuoles and protein deposits. Despite inflammatory muscle pathology suggesting similarity with PM, it likely that IBM is has a prominent degenerative component as supported by refractoriness to immunosuppressive therapy. We review the evolution of our knowledge in IBM with emphasis on recent developments in the field and discuss ongoing clinical trials. PMID:25037082

  2. [Inclusion-body myositis].

    PubMed

    Benveniste, O

    2014-07-01

    Sporadic inclusion-body myositis (sIBM) presents in average at the sixth decade of life and affects three men for one woman. It is a non-lethal, slowly progressive but disabling disease. Except the striated muscles, no other organs (such as the interstitial lung) are involved. The phenotype of this myopathy is particular since it involves the axial muscles (camptocormia, swallowing dysfunction) and limb girdle (notably the quadriceps) but also the distal muscles (in particular the fingers' and wrists' flexors) in a bilateral but non-symmetrical manner. The clinical presentation is then very suggestive of the diagnosis, which remains to be proven by a muscle biopsy. Histological features defining the diagnosis associate endomysial inflammatory infiltrates with frequent invaded fibres (the myositis) and amyloid deposits generally accompanying rimmed vacuoles (the inclusions). There is still today a debate to know if this disease is at its beginning a degenerative or an auto-immune condition. Nonetheless, usual immunosuppressive drugs (corticosteroids, azathioprine, methotrexate) or polyvalent immunoglobulines remain ineffective and even may worsen the handicap. Some controlled randomized trials will soon be launched for this condition, but for now, the best therapeutic approach to slow down the rapidity of progression of the disease is to maintain muscle exercise with the help of the physiotherapists.

  3. Body Shape Preferences: Associations with Rater Body Shape and Sociosexuality

    PubMed Central

    Price, Michael E.; Pound, Nicholas; Dunn, James; Hopkins, Sian; Kang, Jinsheng

    2013-01-01

    There is accumulating evidence of condition-dependent mate choice in many species, that is, individual preferences varying in strength according to the condition of the chooser. In humans, for example, people with more attractive faces/bodies, and who are higher in sociosexuality, exhibit stronger preferences for attractive traits in opposite-sex faces/bodies. However, previous studies have tended to use only relatively simple, isolated measures of rater attractiveness. Here we use 3D body scanning technology to examine associations between strength of rater preferences for attractive traits in opposite-sex bodies, and raters’ body shape, self-perceived attractiveness, and sociosexuality. For 118 raters and 80 stimuli models, we used a 3D scanner to extract body measurements associated with attractiveness (male waist-chest ratio [WCR], female waist-hip ratio [WHR], and volume-height index [VHI] in both sexes) and also measured rater self-perceived attractiveness and sociosexuality. As expected, WHR and VHI were important predictors of female body attractiveness, while WCR and VHI were important predictors of male body attractiveness. Results indicated that male rater sociosexuality scores were positively associated with strength of preference for attractive (low) VHI and attractive (low) WHR in female bodies. Moreover, male rater self-perceived attractiveness was positively associated with strength of preference for low VHI in female bodies. The only evidence of condition-dependent preferences in females was a positive association between attractive VHI in female raters and preferences for attractive (low) WCR in male bodies. No other significant associations were observed in either sex between aspects of rater body shape and strength of preferences for attractive opposite-sex body traits. These results suggest that among male raters, rater self-perceived attractiveness and sociosexuality are important predictors of preference strength for attractive opposite

  4. The older woman's body image.

    PubMed

    Price, Bob

    2010-02-01

    Body image is an important concept that has a significant effect on a person's self-esteem and self-confidence. Appreciating how the older body is perceived by a woman is an important first step to understanding how nurses might support patient dignity. This article reviews the latest literature on ageing and body image and suggests practical dialogues that nurses and patients can share.

  5. The functional architecture of the human body: assessing body representation by sorting body parts and activities.

    PubMed

    Bläsing, Bettina; Schack, Thomas; Brugger, Peter

    2010-05-01

    We investigated mental representations of body parts and body-related activities in two subjects with congenitally absent limbs (one with, the other without phantom sensations), a wheelchair sports group of paraplegic participants, and two groups of participants with intact limbs. To analyse mental representation structures, we applied Structure Dimensional Analysis. Verbal labels indicating body parts and related activities were presented in randomized lists that had to be sorted according to a hierarchical splitting paradigm. Participants were required to group the items according to whether or not they were considered related, based on their own body perception. Results of the groups of physically intact and paraplegic participants revealed separate clusters for the lower body, upper body, fingers and head. The participant with congenital phantom limbs also showed a clear separation between upper and lower body (but not between fingers and hands). In the participant without phantom sensations of the absent arms, no such modularity emerged, but the specific practice of his right foot in communication and daily routines was reflected. Sorting verbal labels of body parts and activities appears a useful method to assess body representation in individuals with special body anatomy or function and leads to conclusions largely compatible with other assessment procedures.

  6. The Body and the Beautiful: Health, Attractiveness and Body Composition in Men's and Women's Bodies.

    PubMed

    Brierley, Mary-Ellen; Brooks, Kevin R; Mond, Jonathan; Stevenson, Richard J; Stephen, Ian D

    2016-01-01

    The dominant evolutionary theory of physical attraction posits that attractiveness reflects physiological health, and attraction is a mechanism for identifying a healthy mate. Previous studies have found that perceptions of the healthiest body mass index (weight scaled for height; BMI) for women are close to healthy BMI guidelines, while the most attractive BMI is significantly lower, possibly pointing to an influence of sociocultural factors in determining attractive BMI. However, less is known about ideal body size for men. Further, research has not addressed the role of body fat and muscle, which have distinct relationships with health and are conflated in BMI, in determining perceived health and attractiveness. Here, we hypothesised that, if attractiveness reflects physiological health, the most attractive and healthy appearing body composition should be in line with physiologically healthy body composition. Thirty female and 33 male observers were instructed to manipulate 15 female and 15 male body images in terms of their fat and muscle to optimise perceived health and, separately, attractiveness. Observers were unaware that they were manipulating the muscle and fat content of bodies. The most attractive apparent fat mass for female bodies was significantly lower than the healthiest appearing fat mass (and was lower than the physiologically healthy range), with no significant difference for muscle mass. The optimal fat and muscle mass for men's bodies was in line with the healthy range. Male observers preferred a significantly lower overall male body mass than did female observers. While the body fat and muscle associated with healthy and attractive appearance is broadly in line with physiologically healthy values, deviations from this pattern suggest that future research should examine a possible role for internalization of body ideals in influencing perceptions of attractive body composition, particularly in women. PMID:27257677

  7. Body size and chronic acceleration

    NASA Technical Reports Server (NTRS)

    Pitts, G. C.

    1976-01-01

    Experiments were conducted to study body composition as a function of acceleration (1-4.7 G) in mice and rats. It is shown that fat-free body mass is a predictable function of acceleration, and that of nine components of the fat-free body mass only skeletal muscle, liver and heart contributed to observed changes induced by delta G. Fat-free body mass was found to pass through a maximum at 1 G when it was plotted vs G for mice, rats and monkeys (1-4.7 G) and men (0-1 G).

  8. [Neuroanatomy of Isolated Body Lateropulsion].

    PubMed

    Nakazato, Yoshihiko; Tamura, Naotoshi; Ikeda, Kei; Tanaka, Ai; Yamamoto, Toshimasa

    2016-03-01

    Axial body lateropulsion, a phenomenon where the body is pulled toward the side of the lesion, with tendency of falling down, is the well-known transient feature of lateral medullary syndrome. In some cases, axial body lateropulsion occurs without vestibular and cerebellar symptoms (isolated body lateropulsion:[iBL]). Patients with iBL have a lesion located in the spinocerebellar tract, descending lateral vestibulospinal tract, vestibulo-thalamic pathway, dentatorubrothalamic pathway, or thalamocortical fascicle. This review deals with the anatomic basis and clinical significance of iBL. PMID:27001775

  9. CORROSION RESISTANT JACKETED METAL BODY

    DOEpatents

    Brugmann, E.W.

    1958-08-26

    Jacketed metal bodies of the type used as fuel elements for nuclear reactors, which contain an internal elongated body of fissionable material jacketed in a corrosion resistant metal are described. The ends of the internal bodies are provided with screw threads having a tapered outer end. The jacket material overlaps the ends and extends into the tapered section of the screw threaded opening. Screw caps with a mating tapered section are screwed into the ends of the body to compress the jacket material in the tapered sections to provtde an effective seal against corrosive gases and liquids.

  10. Body composition in clinical practice.

    PubMed

    Andreoli, Angela; Garaci, Francesco; Cafarelli, Francesco Pio; Guglielmi, Giuseppe

    2016-08-01

    Nutritional status is the results of nutrients intake, absorption and utilization, able to influence physiological and pathological conditions. Nutritional status can be measured for individuals with different techniques, such as CT Body Composition, quantitative Magnetic Resonance Imaging, Ultrasound, Dual-Energy X-Ray Absorptiometry and Bioimpendance. Because obesity is becoming a worldwide epidemic, there is an increasing interest in the study of body composition to monitor conditions and delay in development of obesity-related diseases. The emergence of these evidence demonstrates the need of standard assessment of nutritional status based on body weight changes, playing an important role in several clinical setting, such as in quantitative measurement of tissues and their fluctuations in body composition, in survival rate, in pathologic condition and illnesses. Since body mass index has been shown to be an imprecise measurement of fat-free and fat mass, body cell mass and fluids, providing no information if weight changes, consequently there is the need to find a better way to evaluate body composition, in order to assess fat-free and fat mass with weight gain and loss, and during ageing. Monitoring body composition can be very useful for nutritional and medical interventional. This review is focused on the use of Body Composition in Clinical Practice.

  11. [Neuroanatomy of Isolated Body Lateropulsion].

    PubMed

    Nakazato, Yoshihiko; Tamura, Naotoshi; Ikeda, Kei; Tanaka, Ai; Yamamoto, Toshimasa

    2016-03-01

    Axial body lateropulsion, a phenomenon where the body is pulled toward the side of the lesion, with tendency of falling down, is the well-known transient feature of lateral medullary syndrome. In some cases, axial body lateropulsion occurs without vestibular and cerebellar symptoms (isolated body lateropulsion:[iBL]). Patients with iBL have a lesion located in the spinocerebellar tract, descending lateral vestibulospinal tract, vestibulo-thalamic pathway, dentatorubrothalamic pathway, or thalamocortical fascicle. This review deals with the anatomic basis and clinical significance of iBL.

  12. The "Body Domestic" and the "Body Politic": Education and Advocacy.

    ERIC Educational Resources Information Center

    Thompson, Patricia J.

    This paper offers a new consideration of the "body domestic" and the "body politic" in educational issues. It proposes that these entities be developed as complementary, rather than oppositional, theoretical categories to explain the historical development of, and contemporary issues in, family and consumer sciences (home economics). The text…

  13. Body Fat and Muscle Mass as Functions of Body Water

    ERIC Educational Resources Information Center

    Sutton, R. A.; Miller, Carolyn

    2007-01-01

    Hydrostatic weighing and chemical dilution are well accepted methods for measuring body composition. Recently, Dual Energy X-ray Absorptiometry (DEXA) has become the preferred method. The two compartment algorithms used by these methods assume a fixed constant for lean body tissue. This constant has long been suspect of variations due to many…

  14. Body Talk: Body Image Commentary on Queerty.com.

    PubMed

    Schwartz, Joseph; Grimm, Josh

    2016-08-01

    In this study, we conducted a content analysis of 243 photographic images of men published on the gay male-oriented blog Queerty.com. We also analyzed 435 user-generated comments from a randomly selected 1-year sample. Focusing on images' body types, we found that the range of body types featured on the blog was quite narrow-the vast majority of images had very low levels of body fat and very high levels of muscularity. Users' body image-related comments typically endorsed and celebrated images; critiques of images were comparatively rare. Perspectives from objectification theory and social comparison theory suggest that the images and commentary found on the blog likely reinforce unhealthy body image in gay male communities. PMID:26849832

  15. Body Talk: Body Image Commentary on Queerty.com.

    PubMed

    Schwartz, Joseph; Grimm, Josh

    2016-08-01

    In this study, we conducted a content analysis of 243 photographic images of men published on the gay male-oriented blog Queerty.com. We also analyzed 435 user-generated comments from a randomly selected 1-year sample. Focusing on images' body types, we found that the range of body types featured on the blog was quite narrow-the vast majority of images had very low levels of body fat and very high levels of muscularity. Users' body image-related comments typically endorsed and celebrated images; critiques of images were comparatively rare. Perspectives from objectification theory and social comparison theory suggest that the images and commentary found on the blog likely reinforce unhealthy body image in gay male communities.

  16. Body dissatisfaction, engagement in body change behaviors and sociocultural influences on body image among Chinese adolescents.

    PubMed

    Xu, Xiaoyan; Mellor, David; Kiehne, Melanie; Ricciardelli, Lina A; McCabe, Marita P; Xu, Yangang

    2010-03-01

    Body dissatisfaction and body image disorders are becoming increasingly prevalent in developing non-Western countries such as China, but there is a lack of research examining the sociocultural factors that in other contexts have been associated with these problems. The current study investigated body dissatisfaction, engagement in body change behaviors, and sociocultural pressures on body image, and the relationships between these variables among 517 adolescent males (N=219) and females (N=298) in China. Females reported greater body dissatisfaction than males, and males reported using strategies to increase their muscle bulk more often than females. Males reported pressure from a variety of sociocultural sources to increase their muscles or weight, while females reported pressure from the media to lose weight. For males body dissatisfaction was predicted by pressure from peers to increase their muscle bulk, while for females pressure to lose weight from peers, adult relatives, and the media was likely to increase body dissatisfaction. Pressure from the media and adult relatives was also predictive of body change behaviors in both males and females. The findings are discussed in relation to previous research in both Western and non-Western contexts.

  17. Medicine's Life Inside the Body

    MedlinePlus

    ... A Medicine's Life Inside the Body Inside Life Science View All Articles | Inside Life Science Home Page A Medicine's Life Inside the Body ... Work Computation Aids Drug Discovery This Inside Life Science article also appears on LiveScience . Learn about related ...

  18. Introduction to Exploring Our Bodies

    ERIC Educational Resources Information Center

    Early Childhood Today, 2006

    2006-01-01

    The body is probably one of a child's first science experiments. Young children are curious about their own bodies and how they work. They love to explore how they move (and do not move), the sounds they makes, how they look, how different textures feel on their skin, even how it tastes when they suck their thumb. Activities suggested in this…

  19. Incongruent Bodies: Teaching while Leaking

    ERIC Educational Resources Information Center

    Moore, Lisa Jean

    2007-01-01

    In this article, the author describes her experience, hired seven years ago by a CUNY school, The College of Staten Island (CSI). She expresses that although incredibly challenging, that first year taught her an invaluable lesson. It was through these embodied experiences that she now understands the teacher's body, her body, creates a…

  20. Gravity and body mass regulation

    NASA Technical Reports Server (NTRS)

    Warren, L. E.; Horwitz, B. A.; Fuller, C. A.

    1997-01-01

    The effects of altered gravity on body mass, food intake, energy expenditure, and body composition are examined. Metabolic adjustments are reviewed in maintenance of energy balance, neural regulation, and humoral regulation are discussed. Experiments with rats indicate that genetically obese rats respond differently to hypergravity than lean rats.

  1. Body Language in the Classroom

    ERIC Educational Resources Information Center

    Miller, Patrick W.

    2005-01-01

    Ralph Waldo Emerson and Mae West would seem to have little in common, but there is one thing they both understood--the importance of body language. Educators, psychologists, anthropologists and sociologists define body language or nonverbal communication as communication without words. It includes overt behaviors such as facial expressions, eye…

  2. The Actor and His Body.

    ERIC Educational Resources Information Center

    Rubin, Lucille S., Ed.

    Fourteen brief articles deal with training actors to use their bodies effectively on stage. The articles discuss the following topics: the concept of succession-sequential movement (movement that passes through the body joint by joint); learning physical action through staged fight sequences; techniques of empty-handed combat; protecting students…

  3. Skin Pedagogies and Abject Bodies

    ERIC Educational Resources Information Center

    Kenway, Jane; Bullen, Elizabeth

    2011-01-01

    How does the beauty industry "narrate the skin"? What does it teach women from different cultural groups about the female body? How does skin function as a site where female subjection and abjection are produced and reproduced? In this paper we examine the skin industry pointing to its extreme commodification of the female body and to the…

  4. Body Modification and Suicidal Behavior

    ERIC Educational Resources Information Center

    Hicinbothem, Julie; Gonsalves, Sonia; Lester, David

    2006-01-01

    In a large sample of individuals who belong to a website for body modification, having body modifications (e.g., piercings, tattoos, scarification and surgical procedures) was associated with a higher incidence of prior suicidality (i.e., suicidal ideation and attempted suicide). However, controls for self-reported depression weakened the strength…

  5. Euler's Three-Body Problem.

    ERIC Educational Resources Information Center

    Wild, Walter J.

    1980-01-01

    Discusses the simplest three-body problem, known as Euler's problem. The article, intended for students in the undergraduate mathematics and physics curricula, shows how the complex equations for a specific three-body problem can be solved on a small calculator. (HM)

  6. Longevity, mortality and body weight.

    PubMed

    Samaras, Thomas T; Storms, Lowell H; Elrick, Harold

    2002-09-01

    The purpose of this study was to analyze the relation of total body weight to longevity and mortality. The MEDLINE database was searched for data that allow analysis of the relationship between absolute body weight and longevity or mortality. Additional data were used involving US veterans and baseball players. Trend lines of age at death versus body weight are presented. Findings show absolute body size is negatively related to longevity and life expectancy and positively to mortality. Trend lines show an average age at death versus weight slope of -0.4 years/kg. We also found that gender differences in longevity may be due to differences in body size. Animal research is consistent with the findings presented. Biological mechanisms are also presented to explain why increased body mass may reduce longevity. Life expectancy has increased dramatically through improved public health measures and medical care and reduced malnutrition. However, overnourishment and increased body size have promoted an epidemic of chronic disease and reduced our potential longevity. In addition, both excess lean body mass and fat mass may promote chronic disease.

  7. Re-Educating the Body

    ERIC Educational Resources Information Center

    Holst, Jonas

    2013-01-01

    This article means to investigate the philosophical concept of human embodiment in relation to physical education. As human beings not only do we have a body that we can control, but we "are" our body and live embodied in the world, as the German thinker, Helmuth Plessner, puts it in one of his many contributions to the philosophical…

  8. Central control of body temperature.

    PubMed

    Morrison, Shaun F

    2016-01-01

    Central neural circuits orchestrate the behavioral and autonomic repertoire that maintains body temperature during environmental temperature challenges and alters body temperature during the inflammatory response and behavioral states and in response to declining energy homeostasis. This review summarizes the central nervous system circuit mechanisms controlling the principal thermoeffectors for body temperature regulation: cutaneous vasoconstriction regulating heat loss and shivering and brown adipose tissue for thermogenesis. The activation of these thermoeffectors is regulated by parallel but distinct efferent pathways within the central nervous system that share a common peripheral thermal sensory input. The model for the neural circuit mechanism underlying central thermoregulatory control provides a useful platform for further understanding of the functional organization of central thermoregulation, for elucidating the hypothalamic circuitry and neurotransmitters involved in body temperature regulation, and for the discovery of novel therapeutic approaches to modulating body temperature and energy homeostasis. PMID:27239289

  9. [The ideal body: media pedagogy].

    PubMed

    Ribeiro, Rubia Guimarães; da Silva, Karen Schein; Kruse, Maria Henriqueta Luce

    2009-03-01

    We present enunciations that circulate in the media regarding the body, discussing the ways in which the speeches related with the maintenance of health and aesthetics invest in its improvement. Therefore, we used the Caderno Vida, a weekly insert of Zero Hora, for we understand it as owner of a proper speech that has the power of subjectivate people The analysis is part of Cultural Studies and it is based on the ideas of Michel Foucault. The methodological strategy used was the speech analysis of subjects about body care. The periodical questions its readers using speeches that point to beauty health and success The constructed categories were: how is the ideal body, what to do to have such body and why we must have this body Balanced feeding, practice of regular physical activities and the accomplishment of plastic surgeries are recommendations recurrently found in weekly inserts.

  10. Body Size in Mammalian Paleobiology

    NASA Astrophysics Data System (ADS)

    Damuth, John; MacFadden, Bruce J.

    1990-11-01

    This valuable collection of essays presents and evaluates techniques of body-mass estimation and reviews current and potential applications of body-size estimates in paleobiology. Papers discuss explicitly the errors and biases of various regression techniques and predictor variables, and the identification of functionally similar groups of species for improving the accuracy of estimates. At the same time other chapters review and discuss the physiological, ecological, and behavioral correlates of body size in extant mammals; the significance of body-mass distributions in mammalian faunas; and the ecology and evolution of body size in particular paleofaunas. Coverage is particularly detailed for carnivores, primates, and ungulates, but information is also presented on marsupials, rodents, and proboscideans.

  11. Central control of body temperature

    PubMed Central

    Morrison, Shaun F.

    2016-01-01

    Central neural circuits orchestrate the behavioral and autonomic repertoire that maintains body temperature during environmental temperature challenges and alters body temperature during the inflammatory response and behavioral states and in response to declining energy homeostasis. This review summarizes the central nervous system circuit mechanisms controlling the principal thermoeffectors for body temperature regulation: cutaneous vasoconstriction regulating heat loss and shivering and brown adipose tissue for thermogenesis. The activation of these thermoeffectors is regulated by parallel but distinct efferent pathways within the central nervous system that share a common peripheral thermal sensory input. The model for the neural circuit mechanism underlying central thermoregulatory control provides a useful platform for further understanding of the functional organization of central thermoregulation, for elucidating the hypothalamic circuitry and neurotransmitters involved in body temperature regulation, and for the discovery of novel therapeutic approaches to modulating body temperature and energy homeostasis. PMID:27239289

  12. [Obesity: stigmatization, discrimination, body image].

    PubMed

    Kinzl, Johann F

    2016-03-01

    Obesity is a heterogeneous condition with multifactorial genesis (genetic predisposition, life-style, psychosocial situation), but there is a relatively homogeneous negative stereotype of obese individuals, because overweight and obesity are seen as self-inflicted disorders caused by physical inactivity and disorderd eating behavior. Obese individuals are confronted with far-reaching stigmatization and discrimination. Typical stereotypes are laziness, unattractiveness, work refusal. This negative image by the environment contributes to negative self-awareness and self-stigmatization, accompanied by a poor self-esteem and feelings of poor self-control and reduced self-efficacy, resulting in poor constructive coping strategies for overweight reduction. In addition, a disturbed body image combined with deep dissatisfaction with their own body is often found in many obese individuals. There is not always a close connection between body weight and body dissatisfaction. Young women and individuals with a binge eating disorder often show an increased body dissatisfaction as well. PMID:26883770

  13. Central control of body temperature.

    PubMed

    Morrison, Shaun F

    2016-01-01

    Central neural circuits orchestrate the behavioral and autonomic repertoire that maintains body temperature during environmental temperature challenges and alters body temperature during the inflammatory response and behavioral states and in response to declining energy homeostasis. This review summarizes the central nervous system circuit mechanisms controlling the principal thermoeffectors for body temperature regulation: cutaneous vasoconstriction regulating heat loss and shivering and brown adipose tissue for thermogenesis. The activation of these thermoeffectors is regulated by parallel but distinct efferent pathways within the central nervous system that share a common peripheral thermal sensory input. The model for the neural circuit mechanism underlying central thermoregulatory control provides a useful platform for further understanding of the functional organization of central thermoregulation, for elucidating the hypothalamic circuitry and neurotransmitters involved in body temperature regulation, and for the discovery of novel therapeutic approaches to modulating body temperature and energy homeostasis.

  14. Body fluid identification in forensics.

    PubMed

    An, Ja Hyun; Shin, Kyoung-Jin; Yang, Woo Ick; Lee, Hwan Young

    2012-10-01

    Determination of the type and origin of the body fluids found at a crime scene can give important insights into crime scene reconstruction by supporting a link between sample donors and actual criminal acts. For more than a century, numerous types of body fluid identification methods have been developed, such as chemical tests, immunological tests, protein catalytic activity tests, spectroscopic methods and microscopy. However, these conventional body fluid identification methods are mostly presumptive, and are carried out for only one body fluid at a time. Therefore, the use of a molecular genetics-based approach using RNA profiling or DNA methylation detection has been recently proposed to supplant conventional body fluid identification methods. Several RNA markers and tDMRs (tissue-specific differentially methylated regions) which are specific to forensically relevant body fluids have been identified, and their specificities and sensitivities have been tested using various samples. In this review, we provide an overview of the present knowledge and the most recent developments in forensic body fluid identification and discuss its possible practical application to forensic casework. PMID:23101507

  15. Proximal bodies in hypersonic flow

    SciTech Connect

    Deiterding, Ralf; Laurence, Stuart J; Hornung, Hans G

    2007-01-01

    Hypersonic flows involving two or more bodies travelling in close proximity to one another are encountered in several important situations, both natural and man-made. The present work seeks to investigate one aspect of the resulting flow problem by exploring the forces experienced by a secondary body when it is within the domain of influence of a primary body travelling at hypersonic speeds. An analytical methodology based on the blast wave analogy is developed and used to predict the secondary force coefficients for simple geometries in both two and three dimensions. When the secondary body is entirely inside the primary shocked region, the nature of the lateral force coefficient is found to depend strongly on the relative size of the two bodies. For two spheres, the methodology predicts that the secondary body will experience an exclusively attractive lateral force if the secondary diameter is larger than one-sixth the primary diameter. The analytical results are compared with those from numerical simulations and reasonable agreement is observed if an appropriate normalization for the lateral displacement is used. Results from a series of experiments in the T5 hypervelocity shock tunnel are also presented and compared with perfect-gas numerical simulations, with good agreement. A new force-measurement technique for short-duration hypersonic facilities, enabling the experimental simulation of the proximal bodies problem, is described. This technique provides two independent means of measurement, and the agreement observed between the two gives a further degree of confidence in the results obtained.

  16. Pacemakers charging using body energy.

    PubMed

    Bhatia, Dinesh; Bairagi, Sweeti; Goel, Sanat; Jangra, Manoj

    2010-01-01

    Life-saving medical implants like pacemakers and defibrillators face a big drawback that their batteries eventually run out and patients require frequent surgery to have these batteries replaced. With the advent of technology, alternatives can be provided for such surgeries. To power these devices, body energy harvesting techniques may be employed. Some of the power sources are patient's heartbeat, blood flow inside the vessels, movement of the body parts, and the body temperature (heat). Different types of sensors are employed, such as for sensing the energy from the heartbeat the piezoelectric and semiconducting coupled nanowires are used that convert the mechanical energy into electricity. Similarly, for sensing the blood flow energy, nanogenerators driven by ultrasonic waves are used that have the ability to directly convert the hydraulic energy in human body to electrical energy. Another consideration is to use body heat employing biothermal battery to generate electricity using multiple arrays of thermoelectric generators built into an implantable chip. These generators exploit the well-known thermocouple effect. For the biothermal device to work, it needs a 2°C temperature difference across it. But there are many parts of the body where a temperature difference of 5°C exists - typically in the few millimeters just below the skin, where it is planned to place this device. This study focuses on using body heat as an alternative energy source to recharge pacemaker batteries and other medical devices and prevent the possibility of life-risk during repeated surgery.

  17. Body fluid identification in forensics.

    PubMed

    An, Ja Hyun; Shin, Kyoung-Jin; Yang, Woo Ick; Lee, Hwan Young

    2012-10-01

    Determination of the type and origin of the body fluids found at a crime scene can give important insights into crime scene reconstruction by supporting a link between sample donors and actual criminal acts. For more than a century, numerous types of body fluid identification methods have been developed, such as chemical tests, immunological tests, protein catalytic activity tests, spectroscopic methods and microscopy. However, these conventional body fluid identification methods are mostly presumptive, and are carried out for only one body fluid at a time. Therefore, the use of a molecular genetics-based approach using RNA profiling or DNA methylation detection has been recently proposed to supplant conventional body fluid identification methods. Several RNA markers and tDMRs (tissue-specific differentially methylated regions) which are specific to forensically relevant body fluids have been identified, and their specificities and sensitivities have been tested using various samples. In this review, we provide an overview of the present knowledge and the most recent developments in forensic body fluid identification and discuss its possible practical application to forensic casework.

  18. Body size, body proportions, and mobility in the Tyrolean "Iceman".

    PubMed

    Ruff, Christopher B; Holt, Brigitte M; Sládek, Vladimir; Berner, Margit; Murphy, William A; zur Nedden, Dieter; Seidler, Horst; Recheis, Wolfgang

    2006-07-01

    Body mass and structural properties of the femoral and tibial midshafts of the "Iceman," a late Neolithic (5,200 BP) mummy found in the Tyrolean Alps, are determined from computed tomographic scans of his body, and compared with those of a sample of 139 males spanning the European early Upper Paleolithic through the Bronze Age. Two methods, based on femoral head breadth and estimated stature/bi-iliac (pelvic) breath, yield identical body-mass estimates of 61 kg for the Iceman. In combination with his estimated stature of 158 cm, this indicates a short but relatively wide or stocky body compared to our total sample. His femur is about average in strength compared to our late Neolithic (Eneolithic) males, but his tibia is well above average. His femur also shows adaptations for his relatively broad body (mediolateral strengthening), while his tibia shows adaptations for high mobility over rough terrain (anteroposterior strengthening). In many respects, his tibia more closely resembles those of European Mesolithic rather than Neolithic males, which may reflect a more mobile lifestyle than was characteristic of most Neolithic males, perhaps related to a pastoral subsistence strategy. There are indications that mobility in general declined between the European Mesolithic and late Neolithic, and that body size and shape may have become more variable throughout the continent following the Upper Paleolithic.

  19. Uncommon, undeclared oesophageal foreign bodies.

    PubMed

    Akenroye, M I; Osukoya, A T

    2012-01-01

    We report two cases of unusual and undeclared oesophageal foreign bodies. A small double-rounded calabash or bottle gourd Lagenaria siceraria, stuffed with traditional medicine designed to acquire spiritual power. A whole tricotyledonous kola nut Cola nitida also designed to make medicine to gain love from a woman after passing it out in stool. Each case presented with a sudden onset of total dysphagia and history of ingestion of foreign bodies was not volunteered by any despite direct questioning. Plain radiograph of the neck and chest in either case did not reveal presence of foreign body. Both were successfully removed through rigid oesophagoscopy. PMID:22718184

  20. Virtual reality and virtual bodies

    NASA Astrophysics Data System (ADS)

    Richards, Catherine; Korba, Larry W.; Shaw, Christopher D.; Green, Mark

    1994-04-01

    There are many ways to produce the sense of `presence' or telepresence in the user of virtual reality. For example attempting to increase the realism of the visual environment is a commonly accepted strategy. In contrast, this paper explores a way for the user to feel present in an unrealistic virtual body. It investigates an unusual approach, proprioceptive illusions. Proprioceptive or body illusions are used to generate and explore the experience of virtuality and presence outside of the normal body limits. These projects are realized in art installations.

  1. Protein Bodies of the Soybean

    PubMed Central

    Tombs, M. P.

    1967-01-01

    Some microscope observations of the protein bodies of the cotyledon cells of the soybean (Glycine max) are described, together with changes in their appearance which occur on germination. Density gradient centrifugation permits the isolation of protein bodies from soymeal. They contain about 70% of the protein of the bean. Only 1 protein could be detected in them: glycinin, the major soybean protein. The protein bodies were fractionated to light and heavy fractions. The former contained 97.5% protein, the latter 78.5%. RNA, phytic acid and lipids were also present. The 2 fractions probably differ only in the extent of contamination by other cell fragments. Images PMID:16656574

  2. Gravitational N-Body Simulations

    NASA Astrophysics Data System (ADS)

    Aarseth, Sverre J.

    2010-01-01

    Preface; 1. The N-body problem; 2. Predictor-corrector methods; 3. Neighbour treatments; 4. Two-body regularization; 5. Multiple regularization; 6. Tree codes; 7. Program organization; 8. Initial setup; 9. Decision-making; 10. Neighbour schemes; 11. Two-body algorithms; 12. Chain procedures; 13. Accuracy and performance; 14. Practical aspects; 15. Star clusters; 16. Galaxies; 17. Planetary systems; 18. Small-N experiments; Appendix A. Global regularization algorithms; Appendix B. Chain algorithms; Appendix C. High-order systems; Appendix D. Practical algorithms; Appendix E. KS procedures with GRAPE; Appendix F. Alternative simulation method; Appendix G. Table of symbols; Appendix H. Hermite integration method; References; Index.

  3. Gravitational N-Body Simulations

    NASA Astrophysics Data System (ADS)

    Aarseth, Sverre J.

    2003-10-01

    Preface; 1. The N-body problem; 2. Predictor-corrector methods; 3. Neighbour treatments; 4. Two-body regularization; 5. Multiple regularization; 6. Tree codes; 7. Program organization; 8. Initial setup; 9. Decision-making; 10. Neighbour schemes; 11. Two-body algorithms; 12. Chain procedures; 13. Accuracy and performance; 14. Practical aspects; 15. Star clusters; 16. Galaxies; 17. Planetary systems; 18. Small-N experiments; Appendix A. Global regularization algorithms; Appendix B. Chain algorithms; Appendix C. High-order systems; Appendix D. Practical algorithms; Appendix E. KS procedures with GRAPE; Appendix F. Alternative simulation method; Appendix G. Table of symbols; Appendix H. Hermite integration method; References; Index.

  4. The three-body problem.

    PubMed

    Musielak, Z E; Quarles, B

    2014-06-01

    The three-body problem, which describes three masses interacting through Newtonian gravity without any restrictions imposed on the initial positions and velocities of these masses, has attracted the attention of many scientists for more than 300 years. In this paper, we present a review of the three-body problem in the context of both historical and modern developments. We describe the general and restricted (circular and elliptic) three-body problems, different analytical and numerical methods of finding solutions, methods for performing stability analysis and searching for periodic orbits and resonances. We apply the results to some interesting problems of celestial mechanics. We also provide a brief presentation of the general and restricted relativistic three-body problems, and discuss their astronomical applications. PMID:24913140

  5. The three-body problem.

    PubMed

    Musielak, Z E; Quarles, B

    2014-06-01

    The three-body problem, which describes three masses interacting through Newtonian gravity without any restrictions imposed on the initial positions and velocities of these masses, has attracted the attention of many scientists for more than 300 years. In this paper, we present a review of the three-body problem in the context of both historical and modern developments. We describe the general and restricted (circular and elliptic) three-body problems, different analytical and numerical methods of finding solutions, methods for performing stability analysis and searching for periodic orbits and resonances. We apply the results to some interesting problems of celestial mechanics. We also provide a brief presentation of the general and restricted relativistic three-body problems, and discuss their astronomical applications.

  6. The ORNL whole body counter

    SciTech Connect

    Not Available

    1988-01-01

    This report is a non-technical document intended to provide an individual about to undergo a whole-body radiation count with a general understanding of the counting procedure and with the results obtained. 9 figs. (TEM)

  7. The Mind-Body Problem.

    ERIC Educational Resources Information Center

    Fodor, Jerry A.

    1981-01-01

    Describes several different philosophies of mind with each philosophy's explanation of the mind-body problem. Philosophies discussed include dualism, materialism, functionalism, radical behaviorism, logical behaviorism and central-state identity. (DS)

  8. Origin Story: Blended Wing Body

    NASA Video Gallery

    NASA is partnering with the Boeing Company, among others, to develop and test the blended wing body aircraft. The BWB has the potential to significantly reduce fuel use and noise. In this video, Bo...

  9. Hanford whole body counting manual

    SciTech Connect

    Palmer, H.E.; Brim, C.P.; Rieksts, G.A.; Rhoads, M.C.

    1987-05-01

    This document, a reprint of the Whole Body Counting Manual, was compiled to train personnel, document operation procedures, and outline quality assurance procedures. The current manual contains information on: the location, availability, and scope of services of Hanford's whole body counting facilities; the administrative aspect of the whole body counting operation; Hanford's whole body counting facilities; the step-by-step procedure involved in the different types of in vivo measurements; the detectors, preamplifiers and amplifiers, and spectroscopy equipment; the quality assurance aspect of equipment calibration and recordkeeping; data processing, record storage, results verification, report preparation, count summaries, and unit cost accounting; and the topics of minimum detectable amount and measurement accuracy and precision. 12 refs., 13 tabs.

  10. Ketone bodies as signaling metabolites

    PubMed Central

    Newman, John C.; Verdin, Eric

    2014-01-01

    Traditionally, the ketone body β-hydroxybutyrate (βOHB) has been looked upon as a carrier of energy from liver to peripheral tissues during fasting or exercise. However, βOHB also signals via extracellular receptors and acts as an endogenous inhibitor of histone deacetylases (HDACs). These recent findings support a model in which βOHB functions to link the environment, in this case the diet, and gene expression via chromatin modifications. Here, we review the regulation and functions of ketone bodies, the relationship between ketone bodies and calorie restriction, and the implications of HDAC inhibition by the ketone body βOHB in the modulation of metabolism, and diseases of aging. PMID:24140022

  11. Gravitational Many-Body Problem

    SciTech Connect

    Makino, J.

    2008-04-29

    In this paper, we briefly review some aspects of the gravitational many-body problem, which is one of the oldest problems in the modern mathematical science. Then we review our GRAPE project to design computers specialized to this problem.

  12. Body composition in healthy aging.

    PubMed

    Baumgartner, R N

    2000-05-01

    Health risks in elderly people cannot be evaluated simply in conventional terms of body fatness or fat distribution. Elderly people have less muscle and bone mass, expanded extracellular fluid volumes, and reduced body cell mass compared to younger adults. These nonfat components of body composition play critical roles, influencing cognitive and physical functional status, nutritional and endocrine status, quality of life, and comorbidity in elderly people. Different patterns of "disordered body composition" have different relationships to these outcomes and may require different, tailored approaches to treatment that combine various exercise regimens and dietary supplements with hormone replacement or appetite-stimulating drugs. Skeletal muscle atrophy, or "sarcopenia," is highly prevalent in the elderly population, increases with age, and is strongly associated with disability, independent of morbidity. Elders at greatest risk are those who are simultaneously sarcopenic and obese. The accurate identification of sarcopenic obesity requires precise methods of simultaneously measuring fat and lean components, such as dual-energy X-ray absorptiometry.

  13. Body Language in the Classroom

    ERIC Educational Resources Information Center

    Hennings, Dorothy G.; Grant Barbara M.

    1972-01-01

    Teacher needs to analyze the components of his style, discover excessive activity, experiment with motions and perfect his skill if he is to use body language as an effective communication medium. (RB)

  14. Valve body for oilfield applications

    SciTech Connect

    Bailey, T.F.; Campbell, J.E.

    1992-01-21

    This patent describes a valve to pump fluids, save valve sealingly cooperating with a valve set having a throughbore. It comprises a valve head having an axial cavity with an interior annular side wall; a valve body attached to the valve head, the valve body including an axial neck portion received within the cavity of the valve head and having an outer annular surface corresponding to the interior annular side wall of the cavity; and means to lockingly attach the valve body to the valve head, the valve head being made of a metal material and the valve body being made of an elastomer material, the locking means including at least one annular tongue formed on the outer annular surface of the neck portion of the valve body, the at least one tongue having a frusto-conical upper surface, a cylindrical intermediate surface and a curved lower surface the at least one annular tongue lockingly engaging at least one corresponding annular groove formed in the interior annular side wall of the internal cavity of the valve head thereby preventing inadvertent withdrawal of the neck portion from the cavity and separation of the valve body from the valve head.

  15. Personality disorders and body weight.

    PubMed

    Maclean, Johanna Catherine; Xu, Haiyong; French, Michael T; Ettner, Susan L

    2014-01-01

    We examine the impact of Axis II personality disorders (PDs) on body weight. PDs are psychiatric conditions that develop early in life from a mixture of genetics and environment, are persistent, and lead to substantial dysfunction for the affected individual. The defining characteristics of PDs conceptually link them with body weight, but the direction of the relationship likely varies across PD type. To investigate these links, we analyze data from Wave II of the National Epidemiological Survey of Alcohol and Related Conditions. We measure body weight with the body mass index (BMI) and a dichotomous indicator for obesity (BMI≥30). We find that women with PDs have significantly higher BMI and are more likely to be obese than otherwise similar women. We find few statistically significant or economically meaningful effects for men. Paranoid, schizotypal, and avoidant PDs demonstrate the strongest adverse impacts on women's body weight while dependent PD may be protective against elevated body weight among men. Findings from unconditional quantile regressions demonstrate a positive gradient between PDs and BMI in that the effects are greater for higher BMI respondents.

  16. [The anthropological approach to the "other body"].

    PubMed

    Rozenberg, Jacques J

    2011-06-01

    Research into the anthropology of the body has tackled this wide-reaching concept of the "other body", highly relevant when applied to the field of nursing care. From the healthy biological body to the sick body, the history of anthropology shows the stages of acceptance and rejection of the "other body", male, female and animal.

  17. Sensing the body, representing the body: Evidence from a neurologically based delusion of body ownership.

    PubMed

    Pia, Lorenzo; Garbarini, Francesca; Fossataro, Carlotta; Burin, Dalila; Berti, Anna

    2016-01-01

    Humans experience their own body as unitary and monolithic in nature. However, recent findings in cognitive neuroscience seem to suggest that body awareness has a complex and multifaceted structure that can be dissociated in several subcomponents, possibly underpinned by different brain circuits. In the present paper, we focus on a recently reported neuropsychological disorder of body ownership in which patients misattribute to themselves someone else's arm and its movements. As first, we briefly review the clinical and functional features of this disorder. Secondly, we attempt to explain the nature of the delusion and to gain new hints regarding the mechanisms subserving the construction and the maintenance of the sense of body ownership in the intact brain functioning. PMID:27314302

  18. Accurate body composition measures from whole-body silhouettes

    PubMed Central

    Xie, Bowen; Avila, Jesus I.; Ng, Bennett K.; Fan, Bo; Loo, Victoria; Gilsanz, Vicente; Hangartner, Thomas; Kalkwarf, Heidi J.; Lappe, Joan; Oberfield, Sharon; Winer, Karen; Zemel, Babette; Shepherd, John A.

    2015-01-01

    Purpose: Obesity and its consequences, such as diabetes, are global health issues that burden about 171 × 106 adult individuals worldwide. Fat mass index (FMI, kg/m2), fat-free mass index (FFMI, kg/m2), and percent fat mass may be useful to evaluate under- and overnutrition and muscle development in a clinical or research environment. This proof-of-concept study tested whether frontal whole-body silhouettes could be used to accurately measure body composition parameters using active shape modeling (ASM) techniques. Methods: Binary shape images (silhouettes) were generated from the skin outline of dual-energy x-ray absorptiometry (DXA) whole-body scans of 200 healthy children of ages from 6 to 16 yr. The silhouette shape variation from the average was described using an ASM, which computed principal components for unique modes of shape. Predictive models were derived from the modes for FMI, FFMI, and percent fat using stepwise linear regression. The models were compared to simple models using demographics alone [age, sex, height, weight, and body mass index z-scores (BMIZ)]. Results: The authors found that 95% of the shape variation of the sampled population could be explained using 26 modes. In most cases, the body composition variables could be predicted similarly between demographics-only and shape-only models. However, the combination of shape with demographics improved all estimates of boys and girls compared to the demographics-only model. The best prediction models for FMI, FFMI, and percent fat agreed with the actual measures with R2 adj. (the coefficient of determination adjusted for the number of parameters used in the model equation) values of 0.86, 0.95, and 0.75 for boys and 0.90, 0.89, and 0.69 for girls, respectively. Conclusions: Whole-body silhouettes in children may be useful to derive estimates of body composition including FMI, FFMI, and percent fat. These results support the feasibility of measuring body composition variables from simple

  19. Hanford whole body counting manual

    SciTech Connect

    Palmer, H.E.; Rieksts, G.A.; Lynch, T.P.

    1990-06-01

    This document describes the Hanford Whole Body Counting Program as it is administered by Pacific Northwest Laboratory (PNL) in support of the US Department of Energy--Richland Operations Office (DOE-RL) and its Hanford contractors. Program services include providing in vivo measurements of internally deposited radioactivity in Hanford employees (or visitors). Specific chapters of this manual deal with the following subjects: program operational charter, authority, administration, and practices, including interpreting applicable DOE Orders, regulations, and guidance into criteria for in vivo measurement frequency, etc., for the plant-wide whole body counting services; state-of-the-art facilities and equipment used to provide the best in vivo measurement results possible for the approximately 11,000 measurements made annually; procedures for performing the various in vivo measurements at the Whole Body Counter (WBC) and related facilities including whole body counts; operation and maintenance of counting equipment, quality assurance provisions of the program, WBC data processing functions, statistical aspects of in vivo measurements, and whole body counting records and associated guidance documents. 16 refs., 48 figs., 22 tabs.

  20. The Art of Free-Body Diagrams.

    ERIC Educational Resources Information Center

    Puri, Avinash

    1996-01-01

    Discusses the difficulty of drawing free-body diagrams which only show forces exerted on a body from its neighbors. Presents three ways a body may be modeled: a particle, rigid extended, and nonrigid extended. (MKR)

  1. Genetics Home Reference: inclusion body myopathy 2

    MedlinePlus

    ... Conditions inclusion body myopathy 2 inclusion body myopathy 2 Enable Javascript to view the expand/collapse boxes. ... Open All Close All Description Inclusion body myopathy 2 is a condition that primarily affects skeletal muscles , ...

  2. [Spheroid body myopathy: case report].

    PubMed

    Scola, Rosana Hermínia; Trentin, Alcides Júnior; Vaez, Rodrigo; Gignon, Vinicius de Faria; Costa, Thaís Gurgel; Werneck, Lineu Cesar

    2005-06-01

    Spheroid body myopathy is a rare illness classified in the group of the congenital myopathies as a desmin-related neuromuscular disorder, presenting dominant autosomical origin with the beginning of the symptoms in the adult phase. We report on a seven years old girl with facial paresia, generalized muscular hypotrophy and hypotony, generalized deep areflexia, proximal upper and lower limbs muscular strengh and distal upper limbs grade 3 and distal lower limbs grade 1. Needle electromyography evidenced increased conscription and potentials of motor unit of short duration and low amplitude, characterizing a myopathic standard. The muscle biopsy disclosed mixed standard to myopathy, denervation and inclusion bodies that are consistent to spheroid body myopathy. In this case, the patient presented, in advance, early beginning of the symptoms and there are no similar cases in the family.

  3. Recognizing Body Dysmorphic Disorder (Dysmorphophobia)

    PubMed Central

    Varma, Anukriti; Rastogi, Rajesh

    2015-01-01

    Dysmorphophobia is a psychiatric condition which frequently presents in the clinics of dermatologists and plastic surgeons. This disorder (also called body dysmorphic disorder) is troublesome to the patient whilst being confusing for the doctor. This commonly undiagnosed condition can be detected by a few simple steps. Timely referral to a psychiatrist benefits most patients suffering from it. This article describes with a case vignette, how to recognize body dysmorphic disorder presenting in the dermatological or aesthetic surgery set up. Diagnostic criteria, eitiology, approach to patient, management strategy and when to refer are important learning points. The importance of recognizing this disorder timely and referring the patient to the psychiatrist for appropriate treatment is crucial. This article covers all aspects of body dysmorphic disorder relevant to dermatologists and plastic surgeons and hopes to be useful in a better understanding of this disorder. PMID:26644741

  4. Gravitational effects on body composition in birds

    NASA Technical Reports Server (NTRS)

    Smith, A. H.; Sanchez P., O.; Burton, R. R.

    1975-01-01

    Gallinaceous birds, presenting a wide range of body size, were adapted physiologically to hyperdynamic environments, provided by chronic centrifugation. Chemical composition was measured directly on prepared carcasses, which were anatomically comparable, and more amenable to analysis than the intact body. Body mass and body fat decreased arithmetically with increasing field strength and also with increasing body mass. Water content of lean tissue increased in hyperdynamic environments, but irrespectively of body size.

  5. Realistic Simulation for Body Area and Body-To-Body Networks.

    PubMed

    Alam, Muhammad Mahtab; Ben Hamida, Elyes; Ben Arbia, Dhafer; Maman, Mickael; Mani, Francesco; Denis, Benoit; D'Errico, Raffaele

    2016-01-01

    In this paper, we present an accurate and realistic simulation for body area networks (BAN) and body-to-body networks (BBN) using deterministic and semi-deterministic approaches. First, in the semi-deterministic approach, a real-time measurement campaign is performed, which is further characterized through statistical analysis. It is able to generate link-correlated and time-varying realistic traces (i.e., with consistent mobility patterns) for on-body and body-to-body shadowing and fading, including body orientations and rotations, by means of stochastic channel models. The full deterministic approach is particularly targeted to enhance IEEE 802.15.6 proposed channel models by introducing space and time variations (i.e., dynamic distances) through biomechanical modeling. In addition, it helps to accurately model the radio link by identifying the link types and corresponding path loss factors for line of sight (LOS) and non-line of sight (NLOS). This approach is particularly important for links that vary over time due to mobility. It is also important to add that the communication and protocol stack, including the physical (PHY), medium access control (MAC) and networking models, is developed for BAN and BBN, and the IEEE 802.15.6 compliance standard is provided as a benchmark for future research works of the community. Finally, the two approaches are compared in terms of the successful packet delivery ratio, packet delay and energy efficiency. The results show that the semi-deterministic approach is the best option; however, for the diversity of the mobility patterns and scenarios applicable, biomechanical modeling and the deterministic approach are better choices. PMID:27104537

  6. Realistic Simulation for Body Area and Body-To-Body Networks

    PubMed Central

    Alam, Muhammad Mahtab; Ben Hamida, Elyes; Ben Arbia, Dhafer; Maman, Mickael; Mani, Francesco; Denis, Benoit; D’Errico, Raffaele

    2016-01-01

    In this paper, we present an accurate and realistic simulation for body area networks (BAN) and body-to-body networks (BBN) using deterministic and semi-deterministic approaches. First, in the semi-deterministic approach, a real-time measurement campaign is performed, which is further characterized through statistical analysis. It is able to generate link-correlated and time-varying realistic traces (i.e., with consistent mobility patterns) for on-body and body-to-body shadowing and fading, including body orientations and rotations, by means of stochastic channel models. The full deterministic approach is particularly targeted to enhance IEEE 802.15.6 proposed channel models by introducing space and time variations (i.e., dynamic distances) through biomechanical modeling. In addition, it helps to accurately model the radio link by identifying the link types and corresponding path loss factors for line of sight (LOS) and non-line of sight (NLOS). This approach is particularly important for links that vary over time due to mobility. It is also important to add that the communication and protocol stack, including the physical (PHY), medium access control (MAC) and networking models, is developed for BAN and BBN, and the IEEE 802.15.6 compliance standard is provided as a benchmark for future research works of the community. Finally, the two approaches are compared in terms of the successful packet delivery ratio, packet delay and energy efficiency. The results show that the semi-deterministic approach is the best option; however, for the diversity of the mobility patterns and scenarios applicable, biomechanical modeling and the deterministic approach are better choices. PMID:27104537

  7. Total body water and total body potassium in anorexia nervosa

    SciTech Connect

    Dempsey, D.T.; Crosby, L.O.; Lusk, E.; Oberlander, J.L.; Pertschuk, M.J.; Mullen, J.L.

    1984-08-01

    In the ill hospitalized patient with clinically relevant malnutrition, there is a measurable decrease in the ratio of the total body potassium to total body water (TBK/TBW) and a detectable increase in the ratio of total exchangeable sodium to total exchangeable potassium (Nae/Ke). To evaluate body composition analyses in anorexia nervosa patients with chronic uncomplicated semistarvation, TBK and TBW were measured by whole body K40 counting and deuterium oxide dilution in 10 females with stable anorexia nervosa and 10 age-matched female controls. The ratio of TBK/TBW was significantly (p less than 0.05) higher in anorexia nervosa patients than controls. The close inverse correlation found in published studies between TBK/TBW and Nae/Ke together with our results suggest that in anorexia nervosa, Nae/Ke may be low or normal. A decreased TBK/TBW is not a good indicator of malnutrition in the anorexia nervosa patient. The use of a decreased TBK/TBW ratio or an elevated Nae/Ke ratio as a definition of malnutrition may result in inappropriate nutritional management in the patient with severe nonstressed chronic semistarvation.

  8. Oxidative refolding from inclusion bodies.

    PubMed

    Nelson, Christopher A; Lee, Chung A; Fremont, Daved H

    2014-01-01

    This protocol describes the growth and purification of bacterial inclusion body proteins with an option to selenomethionine label the targeted protein through feedback inhibition of methionine biosynthesis in common (non-auxotrophic) strains of E. coli. The method includes solubilization of inclusion body proteins by chemical denaturation and disulfide reduction, renaturation of the solubilized material through rapid dilution by pulsed injection into refolding buffer containing arginine and a mixture of oxidized and reduced glutathione, recovery of the recombinant protein using a stirred cell concentrator, and removal of the aggregated or misfolded fraction by passage over size-exclusion chromatography. The quality of the resulting protein can be assessed by SDS-PAGE.

  9. Computed tomography of the body

    SciTech Connect

    Lee, J.K.T.; Stanley, R.J.

    1982-01-01

    By the end of the fourth year of clinical use, the number of articles dealing with computed body tomography (CT) had increased exponentially. Over 100 articles were published during this review period. This chapter examines new application of CT in the neck, musculoskeletal system and the breast. The chapter begins with an examination of the technical aspects of the operation and performance of CT scanners during this review period. The anatomy of various regions of the body, such as neck, chest, liver and biliary system, genitourinary tract, and pelvis are examined. Brief discussions of pediatric computed tomography, computed tomography-guided biopsy, and radiation therapy are presented. (KRM)

  10. APPARATUS FOR GRINDING SPHERICAL BODIES

    DOEpatents

    Burch, R.F. Jr.

    1963-09-24

    A relatively inexpensive device is described for grinding rough ceramic bodies into accurate spherical shapes using a conventional drill press and a belt sander. A horizontal disk with an abrasive-surfaced recess in its lower face is mounted eccentrically on a vertical shaft which is forced downward against a stop by a spring. Bodies to be ground are placed in the recess and are subjected to the abrasive action of the belt sander as the disk is rotated by the drill press. (AEC)

  11. Inclusion body myositis and myopathies.

    PubMed

    Sivakumar, K; Dalakas, M C

    1997-10-01

    Sporadic inclusion body myositis is a frequent, acquired, adult-onset vacuolar myopathy affecting proximal and distal muscles with a distinct, easily identifiable clinical pattern. Although its primary cause is still unknown, autoimmune, viral, and degenerative processes, alone or in combination, are being considered. A uniform and sustained therapeutic response using the currently available immunomodulatory agents has not yet been achieved. Hereditary, inherited noninflammatory rimmed vacuolar myopathies with similar histologic features, collectively called hereditary inclusion body myopathies, are being redefined with the use of molecular genetics. The implications of the recent advances in clinical and basic sciences are discussed in the present review.

  12. METHOD OF MAKING REFRACTORY BODIES

    DOEpatents

    Andersen, J.C.

    1960-05-31

    A method is given for the manufacture of silicon carbide bodies that are characterized by high density, high purity, and superior resistance to oxidative deterioration. Dense silicon bodies are obtained by a process in which granular silicon carbide, a carbonizable material, and a carbonaceous material are mixed together, the mixture is shaped as desired, and then the shape is fired in the presence of more than the stoichiometric amount of silicon. The carbonizable material preferably includes a temporary binder that is set before the firing step to hold the mix in shape for firing.

  13. Lexical-semantic body knowledge in 5- to 11-year-old children: How spatial body representation influences body semantics.

    PubMed

    Auclair, Laurent; Jambaqué, Isabelle

    2015-01-01

    This study addresses the relation between lexico-semantic body knowledge (i.e., body semantics) and spatial body representation (i.e., structural body representation) by analyzing naming performances as a function of body structural topography. One hundred and forty-one children ranging from 5 years 2 months to 10 years 5 months old were asked to provide a lexical label for isolated body part pictures. We compared the children's naming performances according to the location of the body parts (body parts vs. head features and also upper vs. lower limbs) or to their involvement in motor skills (distal segments, joints, and broader body parts). The results showed that the children's naming performance was better for facial body parts than for other body parts. Furthermore, it was found that the naming of body parts was better for body parts related to action. These findings suggest that the development of a spatial body representation shapes the elaboration of semantic body representation processing. Moreover, this influence was not limited to younger children. In our discussion of these results, we focus on the important role of action in the development of body representations and semantic organization. PMID:24814800

  14. Lexical-semantic body knowledge in 5- to 11-year-old children: How spatial body representation influences body semantics.

    PubMed

    Auclair, Laurent; Jambaqué, Isabelle

    2015-01-01

    This study addresses the relation between lexico-semantic body knowledge (i.e., body semantics) and spatial body representation (i.e., structural body representation) by analyzing naming performances as a function of body structural topography. One hundred and forty-one children ranging from 5 years 2 months to 10 years 5 months old were asked to provide a lexical label for isolated body part pictures. We compared the children's naming performances according to the location of the body parts (body parts vs. head features and also upper vs. lower limbs) or to their involvement in motor skills (distal segments, joints, and broader body parts). The results showed that the children's naming performance was better for facial body parts than for other body parts. Furthermore, it was found that the naming of body parts was better for body parts related to action. These findings suggest that the development of a spatial body representation shapes the elaboration of semantic body representation processing. Moreover, this influence was not limited to younger children. In our discussion of these results, we focus on the important role of action in the development of body representations and semantic organization.

  15. Experimental Introduction to Moving Bodies.

    ERIC Educational Resources Information Center

    Peterson, Lars Ostrup; Justesen, Uffe

    1996-01-01

    Presents a simple experiment--a marble rolling on a tilted desk--to introduce students to moving bodies. Makes difficult subjects such as measurement, calculus, modeling, and uncertainty easier to identify by putting them into a simple context. Discusses misconceptions, models, and measurements. (JRH)

  16. Holder for rotating glass body

    DOEpatents

    Kolleck, Floyd W.

    1978-04-04

    A device is provided for holding and centering a rotating glass body such as a rod or tube. The device includes a tubular tip holder which may be held in a lathe chuck. The device can utilize a variety of centering tips each adapted for a particular configuration, such as a glass O-ring joint or semi-ball joint.

  17. Education and the Body: Prolegomena

    ERIC Educational Resources Information Center

    Barrow, Robin

    2008-01-01

    There is a need to disentangle various distinct kinds of claim. The body may be important in schooling, though not in education. Movement, sport, fitness and health need to be distinguished. Does sport improve character? Does education imply knowledge about matters of health? Is learning to dance analogous to either learning to play cricket or…

  18. Boys' Bodies in Early Childhood

    ERIC Educational Resources Information Center

    Drummond, Murray

    2012-01-01

    This paper is based on qualitative research data from a project investigating early childhood boys' constructions of masculinities in relation to sport, health and the body. The focus group data, with 33 boys, has been collected in each of the boys' first three years at school. It is part of the data that will be collected over eight years with…

  19. Guy's Guide to Body Image

    MedlinePlus

    ... for Parents for Kids for Teens Teens Home Body Mind Sexual Health Food & Fitness Diseases & Conditions Infections Q&A School & Jobs Drugs & Alcohol Staying Safe Recipes En Español Making a Change – ... KidsHealth > For Teens > A Guy's Guide to ...

  20. The Student Body, for Sale

    ERIC Educational Resources Information Center

    Troop, Don

    2013-01-01

    The sale of bodily goods or services--"body commodification"--is nothing new among college students. But strides in medical technology, the encroachment of market values on all facets of life, and the reach and culture of the Internet have combined to create a fertile environment for people who want or need to exploit the value of their skin or…

  1. Fluid simulation with articulated bodies.

    PubMed

    Kwatra, Nipun; Wojtan, Chris; Carlson, Mark; Essa, Irfan; Mucha, Peter J; Turk, Greg

    2010-01-01

    We present an algorithm for creating realistic animations of characters that are swimming through fluids. Our approach combines dynamic simulation with data-driven kinematic motions (motion capture data) to produce realistic animation in a fluid. The interaction of the articulated body with the fluid is performed by incorporating joint constraints with rigid animation and by extending a solid/fluid coupling method to handle articulated chains. Our solver takes as input the current state of the simulation and calculates the angular and linear accelerations of the connected bodies needed to match a particular motion sequence for the articulated body. These accelerations are used to estimate the forces and torques that are then applied to each joint. Based on this approach, we demonstrate simulated swimming results for a variety of different strokes, including crawl, backstroke, breaststroke, and butterfly. The ability to have articulated bodies interact with fluids also allows us to generate simulations of simple water creatures that are driven by simple controllers. PMID:19910662

  2. Foreign body in the nose

    MedlinePlus

    ... such as marbles), crayon pieces, erasers, paper wads, cotton, and beads. A foreign body in a child's ... DO NOT search the nose with cotton swabs or other tools. This may push the object further into the nose. DO NOT use tweezers or other tools to remove ...

  3. Variability in human body size

    NASA Technical Reports Server (NTRS)

    Annis, J. F.

    1978-01-01

    The range of variability found among homogeneous groups is described and illustrated. Those trends that show significantly marked differences between sexes and among a number of racial/ethnic groups are also presented. Causes of human-body size variability discussed include genetic endowment, aging, nutrition, protective garments, and occupation. The information is presented to aid design engineers of space flight hardware and equipment.

  4. Calculating body frame size (image)

    MedlinePlus

    ... boned category. Determining frame size: To determine the body frame size, measure the wrist with a tape measure and use the following chart to determine whether the person is small, medium, or large boned. Women: Height under 5'2" Small = wrist size less ...

  5. OXALATE DEPOSITION ON ASBESTOS BODIES

    EPA Science Inventory

    The clinical and histopathologic findings in three patients with a deposition of calcium oxalate crystals on ferruginous bodies after occupational exposure to asbestos are provided. In addition, we test the hypothesis that this oxalate can be generated through a nonenzymatic o...

  6. Body dysmorphia and plastic surgery.

    PubMed

    Kyle, Allison

    2012-01-01

    Body dysmorphic disorder is a mental disorder characterized by a preoccupation with some aspect of one's appearance. In cosmetic surgery, this preoccupation can be overlooked by practitioners resulting in a discrepancy between expected and realistic outcome. Identifying the characteristics of this disorder may be crucial to the practitioner-patient relationship in the plastic surgery setting. PMID:22929194

  7. [Diagnostic imaging of "body packers"].

    PubMed

    Ichikawa, K; Tajima, N; Tajima, H; Murakami, R; Okada, S; Hosaka, J; Ito, K; Yamamoto, K; Kumazaki, T; Masuno, T; Yokota, H; Makino, T

    1997-02-01

    Drug smuggling by intra-abdominal concealment, so called "body packing," has recently increased, even in Japan. Because of fatal drug intoxication and other adverse side effects, it is important to make a radiological diagnosis of body packers as soon as possible. A retrospective analysis of the images of plain abdominal radiography, computed tomography (CT) and ultrasound (US) was performed in twenty-three body packers to evaluate the imaging characteristics of three drugs (cannabis, cocaine and heroin). Cannabis (16 patients) and cocaine (5 patients) packages were demonstrated as well-demarcated rectangular-shaped high-density shadows surrounded by gas halo ("double condom sign") in abdominal plain radiographs and CT. Heroin packages (2 patients) were demonstrated as obscure shadows and were difficult to identify on plain radiographs, because they resembled stool masses. US was performed in one cannabis patient because of the refusal of radiological examination, and packages were demonstrated as round echogenic structures with dorsal echo extinctions. In conclusion, abdominal plain radiography, CT and US represent valuable diagnostic modalities in the assessment of body packers.

  8. Bodies Matter in Literacy Coaching

    ERIC Educational Resources Information Center

    Vasudevan, Lalitha

    2014-01-01

    Reading the implicit invitation in new literacies scholarship to reimagine pedagogy that leans into the lives of youth, Vasudevan reminds readers how the teacher's body is central to the meaning making of students in literacy classrooms. She extends this notion of embodiment to the work of the literacy coach and reiterates Skinner, Hagood,…

  9. Space Weathering of Small Bodies

    NASA Astrophysics Data System (ADS)

    McFadden, L. A.

    2002-12-01

    Space weathering is defined as any process that wears away and alters surfaces, here confined to small bodies in the Solar System. Mechanisms which possibly alter asteroid and comet surfaces include solar wind bombardment, UV radiation, cosmic ray bombardment, micrometeorite bombardment. These processes are likely to contribute to surface processes differently. For example, solar wind bombardment would be more important on a body closer to the Sun compared to a comet where cosmic ray bombardment might be a more significant weathering mechanism. How can we measure the effects of space weathering? A big problem is that we don't know the nature of the surface before it was weathered. We are in a new era in the study of surface processes on small bodies brought about by the availability of spatially resolved, color and spectral measurements of asteroids from Galileo and NEAR. What processes are active on which bodies? What physics controls surface processes in different regions of the solar system? How do processes differ on different bodies of different physical and chemical properties? What combinations of observable parameters best address the nature of surface processes? Are there alternative explanations for the observed parameters that have been attributed to space weathering? Should we retain the term, space weathering? How can our understanding of space weathering on the Moon help us understand it on asteroids and comets? Finally, we have to leave behind some presuppositions, one being that there is evidence of space weathering based on the fact that the optical properties of S-type asteroids differs from those of ordinary chondrites.

  10. Many-body wave functions

    SciTech Connect

    Chasman, R.R.

    1995-08-01

    In the past few years, we developed many-body variational wave functions that allow one to treat pairing and particle-hole two-body interactions on an equal footing. The complexity of these wave functions depends on the number of levels included in the valence space, but does not depend on the number of nucleons in the system. By using residual interaction strengths (e.g. the quadrupole interaction strength or pairing interaction strength) as generator coordinates, one gets many different wave functions, each having a different expectation value for the relevant interaction mode. These wave functions are particularly useful when one is dealing with a situation in which the mean-field approximation is inadequate. Because the same basis states are used in the construction of the many-body wave functions, it is possible to calculate overlaps and interaction matrix elements for the many-body wave functions (which are not in general orthogonal) easily. The valence space can contain a large number of single-particle basis states, when there are constants of motion that can be used to break the levels up into groups. We added a cranking term to the many-body Hamiltonian and modified the projection procedure to get states of good signature before variation. In our present implementation, each group is limited to eight pairs of single-particle levels. We are working on ways of increasing the number of levels that can be included in each group. We are also working on including particle-particle residual interaction modes, in addition to pairing, in our Hamiltonian.

  11. Changing bodies changes minds: owning another body affects social cognition.

    PubMed

    Maister, Lara; Slater, Mel; Sanchez-Vives, Maria V; Tsakiris, Manos

    2015-01-01

    Research on stereotypes demonstrates how existing prejudice affects the way we process outgroups. Recent studies have considered whether it is possible to change our implicit social bias by experimentally changing the relationship between the self and outgroups. In a number of experimental studies, participants have been exposed to bodily illusions that induced ownership over a body different to their own with respect to gender, age, or race. Ownership of an outgroup body has been found to be associated with a significant reduction in implicit biases against that outgroup. We propose that these changes occur via a process of self association that first takes place in the physical, bodily domain as an increase in perceived physical similarity between self and outgroup member. This self association then extends to the conceptual domain, leading to a generalization of positive self-like associations to the outgroup. PMID:25524273

  12. Between My Body and My "Dead Body": Narratives of Coma.

    PubMed

    Meoded Danon, Limor

    2016-01-01

    This article is based on narrative research that focuses on corporeal experience during coma and during the rehabilitation process. Seventeen participants from different areas of Israel who had been in various kinds of coma states reveal what the corporeal experience of coma is. The participants are divided into three types of narrative protagonists--"dead-alive," "rational," and "emissaries." Each of the participants redefined the boundaries of the body, especially in cases when they spoke of experiences they did not understand as corporeal, for example, out-of-body experiences, near-death experiences, or experiences of being between the earthly and unearthly. Their struggle to find suitable words to tell their coma stories emphasizes these boundaries between experiencing and telling, which crossed the normative discursive border of the medical establishment and illustrates the ambiguous nature of human existence.

  13. Small Bodies, Big Discoveries: NASA's Small Bodies Education Program

    NASA Astrophysics Data System (ADS)

    Mayo, L.; Erickson, K. J.

    2014-12-01

    2014 is turning out to be a watershed year for celestial events involving the solar system's unsung heroes, small bodies. This includes the close flyby of comet C/2013 A1 / Siding Spring with Mars in October and the historic Rosetta mission with its Philae lander to comet 67P/Churyumov-Gerasimenko. Beyond 2014, the much anticipated 2015 Pluto flyby by New Horizons and the February Dawn Mission arrival at Ceres will take center stage. To deliver the excitement and wonder of our solar system's small bodies to worldwide audiences, NASA's JPL and GSFC education teams in partnership with NASA EDGE will reach out to the public through multiple venues including broadcast media, social media, science and math focused educational activities, observing challenges, interactive visualization tools like "Eyes on the Solar System" and more. This talk will highlight NASA's focused education effort to engage the public in small bodies mission science and the role these objects play in our understanding of the formation and evolution of the solar system.

  14. The Rhetorical Limits of the "Plastic Body"

    ERIC Educational Resources Information Center

    Jordan, John W.

    2004-01-01

    This essay analyzes the "plastic body" as it is produced in the discourse of plastic surgery. The contemporary industry has constructed a popular image of plastic surgery as a readily available and personally empowering means to resolve body image issues, on the presumption that any body can become a "better" body. The ideology underlying the…

  15. 7 CFR 1230.8 - Delegate Body.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Delegate Body. 1230.8 Section 1230.8 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Body. Delegate Body means the National Pork Producers Delegate Body established pursuant to § 1230.30....

  16. 7 CFR 1230.8 - Delegate Body.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Delegate Body. 1230.8 Section 1230.8 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Body. Delegate Body means the National Pork Producers Delegate Body established pursuant to § 1230.30....

  17. 42 CFR 460.62 - Governing body.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 4 2011-10-01 2011-10-01 false Governing body. 460.62 Section 460.62 Public Health... Administrative Requirements § 460.62 Governing body. (a) Governing body. A PACE organization must be operating under the control of an identifiable governing body (for example, a board of directors) or a...

  18. Body Image in the Dance Class

    ERIC Educational Resources Information Center

    Oliver, Wendy

    2008-01-01

    Although some research has shown that dance enhances body image and self-esteem, other research shows that it sometimes has the opposite effect and causes dancers to develop a negative body image and even eating disorders. In dance, body image is not only about maintaining a certain weight; it can also refer to specific perceived body flaws.…

  19. Body Posture Facilitates Retrieval of Autobiographical Memories

    ERIC Educational Resources Information Center

    Dijkstra, Katinka; Kaschak, Michael P.; Zwaan, Rolf A.

    2007-01-01

    We assessed potential facilitation of congruent body posture on access to and retention of autobiographical memories in younger and older adults. Response times were shorter when body positions during prompted retrieval of autobiographical events were similar to the body positions in the original events than when body position was incongruent.…

  20. Not simply a foreign body

    SciTech Connect

    Foltan, R.; Hlousek, M.; Dundr, P.; Skalicky, M.; Hejnak, V.

    2008-02-15

    The presence of foreign biological substances in the human body can lead to violent immune reactions. This is the report of a very rare case involving not only the presence of a biological substance, but also a symbiotic relationship between a living plant (the common wheat grain, Triticum aestivum L.) and the human body. Black coal particles and one cereal grain were removed from the subgalea of the right parietal region of a 35-year-old man who had sustained injuries in a motor vehicle accident 16 days earlier. There were signs of germination of the grain, but no macroscopic or microscopic evidence of an inflammatory reaction. Grain germination was verified microscopically. There are various explanations for the absence of an immune reaction, but only coal-tar-induced immunosuppression can explain the observed phenomenon.

  1. A look at Bodies Corporate.

    PubMed

    Chope, J

    1997-10-11

    One of the most exclusive clubs in the dental world comprises the 27 members who can call themselves Dental Bodies Corporate (DBCs). Among this elite are well-known names such as Dental World, Dencare, Whitecross, Benedent and also Oakley, which is owned by Denplan. In the UK only dentists and DBCs are permitted to carry on the business of dentistry. DBCs are simply companies whose directors (the majority of whom must be dentists) are protected by the laws of limited liability, with the purpose of encouraging investment by shareholders (who need not be dentists). This article outlines the story of how this select band of Corporate Bodies gained their exclusive status which goes back to the very earliest days of our profession.

  2. Body Contouring After Bariatric Surgery.

    PubMed

    Ellison, Jo M; Steffen, Kristine J; Sarwer, David B

    2015-11-01

    Individuals who undergo bariatric surgery generally experience rapid and dramatic weight loss. While the weight loss typically confers significant health benefits, an undesirable consequence is often excessive quantities of hanging, surplus skin. Some patients undergo body-contouring surgery (BCS) in order to improve health, mobility, appearance and psychological adjustment. While the majority of post-bariatric patients desire BCS in one or more body regions, a small percentage of patients receive such surgeries. Lack of knowledge about procedures, cost and (in the USA and several other countries) difficulty obtaining insurance reimbursement likely prevents many patients from undergoing BCS. Those who do undergo BCS appear to be at heightened risk for wound-healing complications. Despite these complications, the majority of patients report satisfactory BCS outcomes. The extant literature in this area provides a great deal of information about these issues; nevertheless, additional research is needed to further inform clinical management and improve patient outcomes.

  3. Barbed sutures in body surgery.

    PubMed

    Moya, Alexander P

    2013-09-01

    Wound-closing technology continues to evolve with the advent of barbed sutures, which appear to address some of the limitations of traditional sutures (numerous knots and time-consuming insertion, among other things). Advantages of knotless suture devices, specifically in body contouring, have been discussed in the literature over the past decade, with a recent increase over the past several years due to the US Food and Drug Administration (FDA) approval of unidirectional V-Loc (Covidien, Mansfield, Massachusetts) and bidirectional Quill (Angiotech Pharmaceuticals, Inc, Vancouver, British Columbia, Canada) barbed sutures for soft tissue approximation. A thorough review of the existing literature and evaluation of the author's personal experience are presented in this article. As with any new surgical device, a learning curve is present that needs to be overcome to realize the full benefits of utilizing barbed sutures in body surgery while minimizing their complications.

  4. What determines human body odour?

    PubMed

    Hamada, Kaoru; Haruyama, Sanehito; Yamaguchi, Takashi; Yamamoto, Kayo; Hiromasa, Kana; Yoshioka, Manabu; Nishio, Daisuke; Nakamura, Motonobu

    2014-05-01

    Human body odour and earwax type are genetically dependent on a single-nucleotide polymorphism (SNP) located in the ABCC11 gene. So far, it still remains to be clear how SNP in the ABCC11 gene is associated with human malodour. In a recent issue of Experimental Dermatology, Baumann et al. propose one of the underlying molecular pathways. Although one of the amino acid conjugated of the odorants, Cys-Gly-3-methyl-3-sulfanylhexanol (3M3SH), was not taken up by the transporter ABCC11, glutathione conjugate of 3MSH (SG-3MSH) was transported by ABCC11. Moreover, SG-3MSH was processed to 3M3SH by γ-glutamyl-transferase 1 (GGT1), which was abundantly expressed in apocrine sweat glands. These findings may pave a way for the pharmacogenetics of human body odour and the development of innovative deodorant products.

  5. Body Contouring After Bariatric Surgery.

    PubMed

    Ellison, Jo M; Steffen, Kristine J; Sarwer, David B

    2015-11-01

    Individuals who undergo bariatric surgery generally experience rapid and dramatic weight loss. While the weight loss typically confers significant health benefits, an undesirable consequence is often excessive quantities of hanging, surplus skin. Some patients undergo body-contouring surgery (BCS) in order to improve health, mobility, appearance and psychological adjustment. While the majority of post-bariatric patients desire BCS in one or more body regions, a small percentage of patients receive such surgeries. Lack of knowledge about procedures, cost and (in the USA and several other countries) difficulty obtaining insurance reimbursement likely prevents many patients from undergoing BCS. Those who do undergo BCS appear to be at heightened risk for wound-healing complications. Despite these complications, the majority of patients report satisfactory BCS outcomes. The extant literature in this area provides a great deal of information about these issues; nevertheless, additional research is needed to further inform clinical management and improve patient outcomes. PMID:26395601

  6. The body fades away: investigating the effects of transparency of an embodied virtual body on pain threshold and body ownership.

    PubMed

    Martini, Matteo; Kilteni, Konstantina; Maselli, Antonella; Sanchez-Vives, Maria V

    2015-09-29

    The feeling of "ownership" over an external dummy/virtual body (or body part) has been proven to have both physiological and behavioural consequences. For instance, the vision of an "embodied" dummy or virtual body can modulate pain perception. However, the impact of partial or total invisibility of the body on physiology and behaviour has been hardly explored since it presents obvious difficulties in the real world. In this study we explored how body transparency affects both body ownership and pain threshold. By means of virtual reality, we presented healthy participants with a virtual co-located body with four different levels of transparency, while participants were tested for pain threshold by increasing ramps of heat stimulation. We found that the strength of the body ownership illusion decreases when the body gets more transparent. Nevertheless, in the conditions where the body was semi-transparent, higher levels of ownership over a see-through body resulted in an increased pain sensitivity. Virtual body ownership can be used for the development of pain management interventions. However, we demonstrate that providing invisibility of the body does not increase pain threshold. Therefore, body transparency is not a good strategy to decrease pain in clinical contexts, yet this remains to be tested.

  7. The body fades away: investigating the effects of transparency of an embodied virtual body on pain threshold and body ownership

    PubMed Central

    Martini, Matteo; Kilteni, Konstantina; Maselli, Antonella; Sanchez-Vives, Maria V.

    2015-01-01

    The feeling of “ownership” over an external dummy/virtual body (or body part) has been proven to have both physiological and behavioural consequences. For instance, the vision of an “embodied” dummy or virtual body can modulate pain perception. However, the impact of partial or total invisibility of the body on physiology and behaviour has been hardly explored since it presents obvious difficulties in the real world. In this study we explored how body transparency affects both body ownership and pain threshold. By means of virtual reality, we presented healthy participants with a virtual co-located body with four different levels of transparency, while participants were tested for pain threshold by increasing ramps of heat stimulation. We found that the strength of the body ownership illusion decreases when the body gets more transparent. Nevertheless, in the conditions where the body was semi-transparent, higher levels of ownership over a see-through body resulted in an increased pain sensitivity. Virtual body ownership can be used for the development of pain management interventions. However, we demonstrate that providing invisibility of the body does not increase pain threshold. Therefore, body transparency is not a good strategy to decrease pain in clinical contexts, yet this remains to be tested. PMID:26415748

  8. Perceptual adaptation affects attractiveness of female bodies.

    PubMed

    Winkler, Christopher; Rhodes, Gillian

    2005-05-01

    We investigated whether short durations (5 minutes) of exposure to distorted bodies can change subsequent perceptions of attractiveness and normality. Participants rated 110 female bodies, varying in width, on either their attractiveness or normality before and after exposure to either extremely narrow (-50% of original width in Experiments 1 and 2) or extremely wide bodies (+50% of original width in Experiment 1, and +70% of original width in Experiment 2). In both experiments, the most attractive and most normal looking bodies became significantly and substantially narrower after exposure to narrow bodies. The most normal looking body changed significantly after exposure to wide bodies, but the most attractive body did not. These results show that perceptions of body attractiveness can be influenced by experience, but that there is an asymmetry between the effects of exposure to narrow and wide bodies. We consider a possible mechanism for this unexpected asymmetry, as well as possible implications for the effects of media exposure on body-image. The most attractive body shape was consistently narrower than the most normal looking body shape. Substantial changes in what looked normal were accompanied by congruent changes in what looked attractive, suggesting that a normal or average body shape may function as a reference point against which body attractiveness is judged. PMID:15969827

  9. Five-body Moshinsky brackets

    SciTech Connect

    Xiao, Shuyuan; Mu, Xueli; Deng, Zhixuan; Chen, Hong

    2015-04-15

    In variational calculations with harmonic oscillator wavefunctions as trial bases, the transformation coefficients that relate harmonic oscillator wavefunctions in two different sets of internal coordinates are convenient to the evaluation of some matrix elements. Here, we present the explicit expression of these transformation coefficients for five-body systems. These transformation coefficients can be collected in a matrix according to the quantum number N of harmonic oscillator shell and can be programmed for arbitrary N. .

  10. Biostereometric analysis of body form

    NASA Technical Reports Server (NTRS)

    Whittle, M. W.; Herron, R. L.; Cuzzi, J. R.

    1977-01-01

    Four-camera stereophotogrammetry of Skylab crewmen, preflight and postflight, revealed a loss of volume of one to one and one-half liters from the legs, much of which was replaced during the first 4 postflight days. It is estimated that about one third of the loss represents partial atrophy due to relative disuse in zero-gravity, the remainder being due to a deficit in body fluid. Reduction in volume of the abdomen has also been noted.

  11. Almond-Shaped Test Body

    NASA Technical Reports Server (NTRS)

    Dominek, Allen; Wood, Richard; Gilreath, Mel

    1992-01-01

    Almond shaped test body developed for use in electromagnetic anechoic chamber for evaluation of range and measurement of components has low radar cross section that varies with angle over large dynamic range. Surface is composite formed by joining properly scaled ellipsoidal surfaces. Used to mount components whose radar cross sections are to be measured, and simulate backscatter characteristics of component as though it were over infinite ground plane.

  12. Body mass index in amputees.

    PubMed

    Tzamaloukas, A H; Patron, A; Malhotra, D

    1994-01-01

    Whereas estimates of percent deviation of body weight from ideal (F delta weight) are corrected for amputation, those of body mass index (BMI) are not, creating discrepancies in evaluating obesity. A correction of the BMI formula for amputation is proposed. The formula for BMI was corrected for amputation mathematically. The mathematical model predicts that the uncorrected BMI formula underestimates body fat in unilateral amputees and overestimates body fat in subjects with bilateral amputations at the same length of the legs. F delta weight and corrected and uncorrected BMI estimates were computed in 15 subjects with unilateral leg amputation and in 8 subjects with multiple amputations. BMI estimates were as follows: in unilateral amputees, corrected 24.1 +/- 4.1 kg/m2, uncorrected 22.2 +/- 3.9 kg/m2 (p < .001); and in multiple amputees, corrected 21.6 +/- 2.4 kg/m2, uncorrected 32.6 +/- 11.8 kg/m2 (p = .043). Linear regressions of F delta weight obtained from standard nutrition assessment on F delta weight computed from uncorrected and corrected BMI values were as follows: in unilateral amputees, uncorrected F delta weight = -0.079 + 0.932 x actual F delta weight, r = .974, p < .01, and corrected F delta weight = 0.002 + 1.005 x actual F delta weight, r = .997, p < .01; in multiple amputees, uncorrected F delta weight = 0.528 + 1.930 x actual F delta weight, r = .607, p is not significant, and corrected F delta weight = -0.010 + 0.920 x actual F delta weight, r = .936, p < .01.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Galileo's Exploration of Small Bodies

    NASA Astrophysics Data System (ADS)

    Johnson, Torrence

    The Galileo mission to the Jupiter system afforded the opportunity to make the first ever flyby observations of main belt asteroids. The first encounter with 951 Gaspra revealed an irregular cratered surface that shows evidence of regolith optical space weatering processes. The second encounter with 243 Ida resulted in the discovery of the first confirmed satellite of an asteroid Dactyl. Measruements of Dactyl's orbit also allowed a useful determination of mass and density for Ida. In addition to these pioneering asteroid observations Galileo also made observations of Jupiter's small inner moons and found that they were the major source for material in Jupiter's tenuous ring system. During it's final data taking orbit in 2002 Galileo passed within about 250 km of the irregularly shaped satellite Amalthea. Determination of Amalthea's mass from tracking data yields a bulk density for this small body of less than 1 gm/cc suggesting a body of relatively high porosity. This is consistent with the growing body of data on small asteroid densities and estimates of their porosity

  14. Galileo's Exploration of Small Bodies

    NASA Astrophysics Data System (ADS)

    Johnson, Torrence

    2005-01-01

    The Galileo mission to the Jupiter system afforded the opportunity to make the first ever flyby observations of main belt asteroids. The first encounter with 951 Gaspra revealed an irregular cratered surface that shows evidence of regolith optical space weatering processes. The second encounter with 243 Ida resulted in the discovery of the first confirmed satellite of an asteroid Dactyl. Measruements of Dactyl's orbit also allowed a useful determination of mass and density for Ida. In addition to these pioneering asteroid observations Galileo also made observations of Jupiter's small inner moons and found that they were the major source for material in Jupiter's tenuous ring system. During it's final data taking orbit in 2002 Galileo passed within about 250 km of the irregularly shaped satellite Amalthea. Determination of Amalthea's mass from tracking data yields a bulk density for this small body of less than 1 gm/cc suggesting a body of relatively high porosity. This is consistent with the growing body of data on small asteroid densities and estimates of their porosity.

  15. Basal body structure in Trichonympha.

    PubMed

    Guichard, Paul; Gönczy, Pierre

    2016-01-01

    Trichonympha is a symbiotic flagellate of many species of termites and of the wood-feeding cockroach. Remarkably, this unicellular organism harbors up to over ten thousand flagella on its surface, which serve to propel it through the viscous environment of the host hindgut. In the 1960s, analysis of resin-embedded Trichonympha samples by electron microscopy revealed that the basal bodies that give rise to these flagella are exceptionally long, with a proximal, cartwheel-bearing, region some 50 times longer than that of regular centrioles. In recent years, this salient feature has prompted the analysis of the 3D architecture of Trichonympha basal bodies in the native state using cryo-electron tomography. The resulting ~40 Å resolution map of the basal body proximal region revealed a number of novel features that may be conserved in centrioles of other systems. These include proximal-distal polarity of the pinhead structure that links the cartwheel to centriolar microtubules, as well as of the linker between the A and the C microtubules. Moreover, this work demonstrated that the cartwheel is made of stacked ring-like structures that likely each comprise 18 molecules of SAS-6 proteins. PMID:26937279

  16. Plasma Escape from Unmagnetized Bodies

    NASA Technical Reports Server (NTRS)

    Hartle, R. E.; Grebowsky, J. M.; Intriligator, D. S.

    1998-01-01

    A considerable fraction of atmospheric loss at Venus and Titan is in the form of plasma escape. This is due in part to the fact that the ionospheres of these unmagnetized bodies interact directly with the high speed plasmas flowing around them. The similarities of the interactions help reinforce interpretations of measurements made at each body, especially when instruments and measurement sites differ. For example, it is well established through this method that ions born in the exospheres above the ionopauses are picked up and carried away by the solar wind at Venus and the rotating plasma in Saturn's magnetosphere. On the other hand, it is more difficult to relate the observations associated with escape of cooler ionospheric plasma down the ionotails of each body. A clear example of ionospheric plasma escaping Titan was observed as it flowed down its ionotail (1). Measurements at Venus have not as yet clearly distinguished between ionospheric and pickup ion escape in the ionotail; however, cold ions detected in the distant wake at 1 AU by the CELIAS/CTOF instrument on SOHO have been interpreted as ionospheric in origin (2). An algorithm to determine ionospheric flow from Pioneer Venus aeronomical measurements is used to show that escape of cold ionospheric plasma is likely to occur. These results along with plasma flow measurements made in the ionotail of Venus are combined and compared to the corresponding flow at Titan.

  17. Four-body trajectory optimization

    NASA Technical Reports Server (NTRS)

    Pu, C. L.; Edelbaum, T. N.

    1973-01-01

    A collection of typical three-body trajectories from the L1 libration point on the sun-earth line to the earth is presented. These trajectories in the sun-earth system are grouped into four distinct families which differ in transfer time and delta V requirements. Curves showing the variations of delta V with respect to transfer time, and typical two and three-impulse primer vector histories, are included. The development of a four-body trajectory optimization program to compute fuel optimal trajectories between the earth and a point in the sun-earth-moon system are also discussed. Methods for generating fuel optimal two-impulse trajectories which originate at the earth or a point in space, and fuel optimal three-impulse trajectories between two points in space, are presented. A brief qualitative comparison of these methods is given. An example of a four-body two-impulse transfer from the Li libration point to the earth is included.

  18. Menzerite-(Y) a New Species {(Y REE)(Ca Fe2plus)2}[(Mg Fe2plus)(Fe3plus Al)](Si3)O12 from a Felsic Granulite Parry Sound Ontario and a New Garnet End-member (Y2Ca)Mg2(SiO4)3

    SciTech Connect

    E Grew; J Marsh; M Yates; B Lazic; T Armbruster; A Locock; S Bell; M Dyar; H Bernhardt; O Medenbach

    2011-12-31

    Menzerite-(Y), a new mineral species, forms reddish brown cores, n = 1.844 (20), up to 70 {micro}m across, rimmed successively by euhedral almandine containing up to 2.7 wt% Y{sub 2}O{sub 3} and by K-feldspar in a felsic granulite on Bonnet Island in the interior Parry Sound domain, Grenville Orogenic Province, Canada. It is named after Georg Menzer (1897-1989), the German crystallographer who solved the crystal structure of garnet. Single-crystal X-ray-diffraction results yielded space group Ia3d, a = 11.9947(6) {angstrom}. An electron-microprobe analysis of the grain richest in Y (16.93 wt% Y{sub 2}O{sub 3}) gave the following formula, normalized to eight cations and 12 oxygen atoms: {l_brace}Y{sub 0.83}Gd{sub 0.01}Dy{sub 0.05}Ho{sub 0.02}Er{sub 0.07}Tm{sub 0.01}Yb{sub 0.06}Lu{sub 0.02}Ca{sub 1.37}Fe{sub 0.49}{sup 2+}Mn{sub 0.07}{r_brace} [Mg{sub 0.55}Fe{sub 0.42}{sup 2+}Fe{sub 0.58}{sup 3+}Al{sub 0.35} V{sub 0.01}Sc{sub 0.01}Ti{sub 0.08}](Si{sub 2.82}Al{sub 0.18})O{sub 12}, or {l_brace}(Y,REE)(Ca,Fe{sup 2+}){sub 2}{r_brace}[(Mg,Fe{sup 2+})(Fe{sup 3+},Al)](Si{sub 3})O{sub 12}. Synchrotron micro-XANES data gave Fe{sup 3+}/{Sigma}Fe = 0.56(10) versus 0.39(2) calculated from stoichiometry. The scattering power refined at the octahedral Y site, 17.68 epfu, indicates that a relatively light element contributes to its occupancy. Magnesium, as determined by electron-microprobe analyses, would be a proper candidate. In addition, considering the complex occupancy of this site, the average Y-O bond length of 2.0244(16) {angstrom} is in accord with a partial occupancy by Mg. The dominance of divalent cations with Mg > Fe{sup 2+} and the absence of Si at the octahedral Y site (in square brackets) are the primary criteria for distinguishing menzerite-(Y) from other silicate garnet species; the menzerite-(Y) end-member is {l_brace}Y{sub 2}Ca{r_brace}[Mg{sub 2}](Si{sub 3})O{sub 12}. The contacts of menzerite-(Y) with almandine are generally sharp and, in places, cuspate. It is

  19. The relation of body dissatisfaction to salience of particular body sizes

    PubMed Central

    Seifert, A.L.; Arnell, K.M.; Kiviniemi, M.T.

    2009-01-01

    Objective Research examining body image schemas has found that individuals high in body dissatisfaction direct increased attention toward body shapes relative to neutral stimuli. However, it is not known whether attention is attracted to particular body shapes over others (e.g., thin or obese). The present study examined whether body dissatisfaction would moderate the extent to which women find thin, average, and/or obese body sizes salient. Method Women with high and low body dissatisfaction (N=32) completed an indirect cognitive task assessing the relative salience of different body sizes (thin, average, obese). Results Degree of body dissatisfaction was inversely related to frequency estimates of obese body sizes; highly dissatisfied participants found obese body sizes less salient. Conclusion These results highlight the importance of examining the salience of specific body sizes. The present study has implications for understanding cognitive aspects of social comparison and body dissatisfaction. PMID:19169068

  20. An examination of body tracing among women with high body dissatisfaction.

    PubMed

    Williams, Gail A; Hudson, Danae L; Whisenhunt, Brooke L; Crowther, Janis H

    2014-09-01

    Within eating disorder treatment programs, a body tracing activity is often used to address body dissatisfaction and overestimation of body size; however, the effects of this activity have never been empirically evaluated. This research examined the effects of body tracing on body dissatisfaction and mood among 56 female participants assigned to either a body tracing or control group. Scores were collected on trait body dissatisfaction and a series of Visual Analogue Scales (VAS). Results showed that trait body dissatisfaction moderated the relationship between group and levels of state appearance dissatisfaction and anxiety. These results suggest that individuals experiencing higher levels of trait body dissatisfaction demonstrated greater state body dissatisfaction following participation in the body tracing activity. Individuals with lower trait body dissatisfaction experienced greater anxiety after drawing a human body. These findings have potential implications for the use of this strategy in the treatment of eating disorder patients.