Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 26 for “"thermobarometry"”.
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Thermobarometry of Hawaiian Spinel Peridotites
<p>Mantle peridotite xenoliths found within the rejuvenated stage lavas on the islands of O`ahu and Kaua`i, Hawaii provide a unique window into the oceanic mantle. These peridotites are thought to represent variably metasomatized fragments of the Pacific lithosphere. If these peridotites are …
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Applications of Elastic Modeling, Thermobarometry, and Thermal History Modeling to (Ultra)high-Pressure Metamorphic Rocks
… subduction zone metamorphic rocks. Elastic thermobarometry, trace element thermobarometers, and numerical modeling approaches were integrated to determine P–T(–t) histories of (U)HP metamorphic rocks. In the first chapter of this dissertation, multi-diffusion domain numerical modelling of …
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Thermobarometry and geochemistry of peridotite xenoliths from the southwestern margin of the Kaapvaal craton, South Africa
… I kimberlites studied here. Major element-based thermobarometry results and the resulting FITPLOT paleogeotherms indicate that at the time of Grp II kimberlite magmatism the Namaqua-Natal lithosphere was ~ 200 km thick, with a 60 km “diamond window”, and had a geothermal gradient of 40 mW/m2 . In …
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Mechanisms of Shear Zone Localization and Raman Thermobarometry in Spinel Peridotites from the Alpine Fault, New Zealand
<p> A suite of xenoliths from two localities on South Island, New Zealand, exhibit rare microstructures and provide information on deformation during the early stages of development of the Alpine Fault. The first set of samples has evidence of dislocation creep with subgrains, recrystallized …
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Thermobarometry, ⁴⁰A r/³⁹Ar geochronology, and structure of the Main Central Thrust zone and Tibetan Slab, eastern Nepal Himalaya
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1988.
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Constraining Metamorphic and Tectonic Evolution in Convergent Terranes: How Trace Elements and Mineral Inclusions Shape Mechanical and Reconstructive Models
Conventional thermobarometry in metamorphic systems has been primarily limited to constraining peak temperature (or pressure) along a generalized P-T loop. This is largely attributed to the assumption that mineral assemblages and chemistries achieve a state closest to equilibrium with the maximum …
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Inferring the thermomechanical state of the lithosphere using geophysical and geochemical observables
… crustal geodynamics. In Chapter 2, I utilize thermobarometry, diffusion models, and thermodynamic modelling to constrain the ultra-high formation conditions and cooling rates of the Gore Mountain Garnet Amphibolite in order to understand the rheology of the lower crust during orogenic …
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Geochemical Constraints of Porphyry Cu Deposits-Forming Magmas in Sonora, Mexico
… geochemistry, U–Pb geochronology, and thermobarometry, I assess the magmatic conditions under which PCDs and barren rocks formed, and identify key proxies, such as REE anomalies, H₂O content, and oxidation state, that distinguish fertile magmas from barren magmatic systems. These …
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Inferring the Thermomechanical State of the Lithosphere Using Geophysical and Geochemical Observables
… crustal geodynamics. In Chapter 2, I utilize thermobarometry, diffusion models, and thermodynamic modelling to constrain the ultra-high formation conditions and cooling rates of the Gore Mountain Garnet Amphibolite in order to understand the rheology of the lower crust during orogenic …
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Pressure, temperature, and stress conditions of Southern Alpine Fault (New Zealand) mylonites
… Alpine Fault. Constraints from Ti-in-quartz thermobarometry and Raman Spectroscopy of Carbonaceous Material (RSCM) indicate mylonitization occurred at 390 – 495 °C, somewhat cooler than observed along the central Alpine Fault. Given similar bulk compositions, and no known variation in strain …
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Metamorphic P-T Path and Multiple Fluid Events During Burial and Exhumation of the Tso Morari UHP Terrane, NW Himalaya
… protocols are consistent with the conventional thermobarometry results and petrographic observations from the Tso Morari eclogites. Secondly, thermodynamic modelling using P-M(H2O) pseudosections on Tso Morari UHP rocks indicates three distinct fluid events during the prograde and retrograde …
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Structural and petrologic aspects of the emplacement of granitoid plutons : case studies from the western margin of the Joshua Flat-Beer Creek-Pluton (White-Inyo Mountains, California) and the Flasergranitoid zone (Odenwald, Germany)
… --> Beer Creek Granodiorite as nested diapirs. Thermobarometry shows that the JBP intruded at temperatures between 664 and 900 °C into a depth of c. 8 km. In the contact aureole three metamorphic zones were distinguished with decreasing distance from the pluton: the andalusite-cordierite, …
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Transitions between effusive and explosive activity at Merapi volcano, Indonesia: a volcanological and petrological study of the 2006 and 2010 eruptions.
… geochemical analysis, mineral compositions and thermobarometry, quantitative textural analysis of feldspar microlites and analysis of volatiles and light lithophile elements in melt inclusions. These data were gathered from a detailed set of stratigraphically controlled samples, correlated to …
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Metamorphism in the Northern Front Range, Colorado
Thermobarometry, detailed petrography, electron microprobe analysis, and fluid inclusion microthermometry were used to quantify the history of a high grade Proterozoic terrane exposed within the northeastern Colorado Front Range. Pressure-temperature calculations identified two blocks from …
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The magmatic-hydrothermal fluid history of the Harrison Pass Pluton, Ruby Mountains, NV: implications for the Ruby Mountains-East Humboldt Range metamorphic core complex and Carlin-type Au deposits
… disagreement exists between published mineral thermobarometry data and stratigraphic reconstructions. Synchronous with emplacement of the HPP was a regional hydrothermal fluid event responsible for deposition of >200 Moz of Au in sediment-hosted Carlin-type deposits (CTD's) along four linear …
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Guiana Shield diamonds, the sub-cratonic lithosphere, and kimberlite emplacement in the upper crust.
… conditions (log ƒO2 (ΔFMQ) -1.6±1.1). Raman thermobarometry suggests entrapment at 5 – 7 GPa within cratonic roots. Low OH active infrared absorbances indicate low ppm H2O contents of forsterite inclusions, from which we were able to estimate high viscosities of 1023.7±2.1 Pa∙s within the …
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Magmatic processes recorded in crystals from intraplate basalt volcanoes, Kaikohe-Bay of Islands volcanic field, New Zealand
… with depths calculated from clinopyroxene thermobarometry. Thus, it can be inferred that buoyancy and/or rheology contrasts may have caused basalt magmas to temporarily or permanently stall, promoting crystallisation and interaction with earlier magmas or intrusions. The magmas are derived …
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Investigations of Trace Element Titanium in Silica Minerals
… mineral to target for thermobarometric uses. Thermobarometry is the quantitative determination of the pressure (baro-) and temperature (thermo-) conditions at which a natural rock sample reached chemical equilibrium. This dissertation contains three chapters describing mineral synthesis …
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Kimberlites, megacrysts and related xenocrysts from southern and Central Africa: geochemistry and petrology
… The geochemistry and single mineral thermobarometry of peridotitic clinopyroxene xenocrysts suggests that the SCLM is cooler and more depleted beneath Tshibwe compared to that below Mbuji-Mayi, and this is consistent with the finding from this work that the age of Tshibwe is 84 Ma, …
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Petrology of the Taconian-Acadian Overlap Zone, Hartland Belt, Western Connecticut
… thermodynamic database with the software TWEEQU (thermobarometry with estimations of equilibria). Both of these methods produced consistent results with peak P-T conditions of 575-650 °C and 6-9 kbars. Wavelength dispersive X-ray compositional images (WDS images) along with quantitative traverses …
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