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 13 of 13 for “"metamorphic assemblages"”.
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Variable water pressure metamorphic assemblages in the Meguma Group, Nova Scotia
… P<sub>H₂O</sub> estimates based on Ms-and-Pl-V assemblages indicate that P<sub>H₂O</sub> = .4-.9 P<sub>Total</sub> for rocks from the Shelburne area and P<sub>H₂O</sub>=P<sub>Total</sub> for the rocks south of West Pubnico. Whole rock chemical analyses on samples from the three traverses show no …
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Characterization of metamorphic assemblages and assessment of Cu-Pb-Ag-Au-Zn mobility at the Lalor deposit, Snow Lake, Manitoba
… the Paleoproterozoic Flin Flon belt. A regional metamorphic event at 1.81 Ga, up to middle amphibolite facies (550˚C, 5kbar), recrystallized the mineral assemblages in the massive sulfide and hydrothermally altered rocks that are associated with the formation of VMS deposits in the area. The …
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A detailed petrographic and oxygen isotope study of metamorphic rocks and archean basement complex Gneisses from the Vredefort dome, South Africa
… in the core ofthe dome. In the collar, two metamorphic assemblages have been identified, one representing a peak metamorphic event pre-impact in age and constrained to temperatures >420-620°C at 3.0-4.0 kbar, and a younger retrograde event, constrained to 500-540 ± 15°C, which overprints the …
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Tectonic development of Proterozoic structures and their influence on Laramide and Miocene deformation, north Virgin Moutains, SE Nevada and NW Arizona
… by distinct structural fabrics and associated metamorphic assemblages and microstructures. The most prominent Proterozoic structure is the Virgin Mountains shear zone (VMSZ), which was initially defined as a crustal weak zone during D1 northeast-southwest contraction and may represent an …
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The effects of high temperature metamorphic and melting processes on granulite-facies rocks
This thesis presents research on high-temperature metamorphic processes. A recent development in petrological modelling of granulite facies rocks is reintegration of melt generated and lost during metamorphism. The aim of melt reintegration is to create bulk compositions suitable for modelling …
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On Ultra-High Temperature Metamorphism in the Mid-Lower Crust
… natural example of ultra-high temperature (UHT) metamorphic processes and country rock-magma interaction due to mappable units of hybrid igneous rocks and the presence of large, partially melted, politic "emery" xenoliths. Previous attempts to understand the formation of the UHT xenoliths in the …
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Archean metamorphism in northwestern Ontario and southeastern Manitoba
… province) and Wabigoon Subprovince indicate that metamorphic conditions were 2-4 kb and 425-600°C (Fig. 3). </p><p> The Vermilion River logging road crosses the English River Subprovince and has four lithologies that are useful in determining metamorphic conditions: hypersthene ± clinopyroxene …
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Structural and metamorphic evolution of an area around Kakamas and Keimoes, Cape Province, South Africa
… event M2 is characterised by contact metamorphic assemblages as a result of the emplacement of hyperstene bearing granitoids. These intrusions undoubtedly postdate D 2 but appear to have suffered from some shearing. n+ Vertical displacement along the two main shear zones (Neusspruit …
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The stratigraphy and metamorphism of the Snyder Group, Labrador
… an Aphebian platform assemblage. Three zones of metamorphic grade are defined by the aluminum silicates: I, andalusite; II, andalusite-sillimanite; III, sillimanite. Anatexis has occurred in zone III. The total width of the aureole is 2-2.5 km. Progressive metamorphic assemblages are: …
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Polyphase Proterozoic tectonometamorphic history of the Taos Range, northern New Mexico
… Ga plutons. Supracrustal rocks preserve peak metamorphic conditions of T less than or equal to 650 degrees Celsius, 6-8 kb in the northern Taos Range, and T greater than or equal to 550 degrees Celsius, 6 kb in the southern Taos Range. In the northern Taos Range, relationships between field …
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A coming together: The juxtaposition of the Rae and Hearne cratons along the Virgin River shear zone (Snowbird tectonic zone), Saskatchewan, Canada, and the implications for proto-Laurentia
… along the southwestern margin of the Rae. The metamorphic culmination of the Taltson orogeny developed at 1.94-1.93 Ga, independently of the Thelon orogeny, which culminated some 10-20 million years earlier. The footwall of the Virgin River shear zone comprises rocks of the southern Hearne …
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The Mesoproterozoic Hallandian event - a region-scale orogenic event in the Fennoscandian Shield
… Segment, which bears the imprint of at least two metamorphic events; the 1460-1380 Ma Hallandian and the 1150-970 Ma Sveconorwegian. However, the nature and extent of the Hallandian event have been difficult to access due to the Sveconorwegian, effectively masking earlier metamorphic assemblages, …
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Tectono-metamorphic history of the re-worked, high-grade Maud Belt at central-Eastern H.U. Sverdrupfjella, Antarctica
… will either completely overprint earlier peak assemblages or prevent the formation of new 'peak' minerals. The extent of reworking in granulites is controlled by three main factors, namely: (1) the pressures and temperatures reached in earlier and later metamorphic events, (2) the extent of …