The minimum T-XCO₂ location of the reaction boundary calcite + quartz + rutile = sphene + CO₂ has been experimentally determined in H₂0-CO₂-NaCl fluids at 2 kbar. Extent and direction of reaction were monitored by the CO₂ weight change method using natural materials. All bulk compositions contain 23 wt. % NaCI, relative to NaCl-H₂0. Synthetic fluid inclusions trapped at the T-XCO₂ conditions of several points along the curve suggest unmixing of the fluid phase, as evidenced by coexisting CO₂ vapor-rich and aqueous, halite-bearing inclusions. Results from 450-520 °C are listed below. / Master of Science

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on December 28, 2007) Includes bibliographical references.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2005. / Includes bibliographical references. Also available online.

Graduation date: 1991

No description available.

No description available.

No description available.

Detailed structural and mineralogical mapping was undertaken in an area of 130 square kilometres within the Pennine Zone of the south-east Tauern Window, the Eastern Alps. A coherent tectono-metamorphic history is established for this area. Three pre-Alpine metamorphic events are recognised. The Alpine history involves two discrete phases of intense penetrative deformation which occurred under conditions of rising temperature, a widespread phase of thermal crystallisation at 35-40 mybp representing the attainment of maximum temperatures, and a minor post-metamorphic phase of deformation. The regional tectonic significance of this sequence is discussed. The spatial variation in Alpine peak metamorphic conditions is examined in terms of the distribution of mineral zones and isograds in metapelites. Staurolite+biotite assemblages were developed at low structural levels, and chloritoid+biotite assemblages along a thin wedge-shaped zone. Barrovian and Stonehavian facies series are both represented. Oxygen isotope studies on whole-rocks and mineral separates suggest that widespread circulation of metamorphic fluids did not occur during Alpine metamorphism. Thermodynamic calculations indicate that metamorphic conditions during the Alpine thermal peak were 570ºC and 7 kb at the basement-cover interface. These results can be reconciled both with models in which tectonic burial alone was sufficient to cause Alpine metamorphism of the Pennine Zone and with models in which a transient high heat flow regime is invoked.

This thesis attempts to unravel the complex thermal and structural history of part of the High Himalayan Slab in NW India and combines reconnaissance-style field structural mapping of an area covering ~10,000 km² with petrography, microstructural analysis, thermobarometry and geochronology techniques. The results of this work show that the oldest protoliths of the High Himalayan Slab are at least Cambrian in age and that they may have experienced a major pre-Himalayan metamorphism at c.500 Ma. The youngest protoliths are Mesozoic in age (the Tandi Group) and demonstrate that the High Himalayan Slab represents the metamorphosed equivalents of the Tibetan Sedimentary Series. Metamorphism was achieved via substantial crustal shortening and thickening following the India-Asia collision at 50-54 Ma ago. Phase relationships demonstrate that metamorphism was a regional Barrovian-type event associated with the growth of biotite-, garnet-, staurolite-, kyanite- and sillimanite-bearing assemblages in metapelites. Quantitative thermobarometry demonstrates that near-peak conditions of c.6-8 kbar and 550-650°C were attained in the deepest exposed levels. Growth of metamorphic assemblages was underway by at least 30 Ma, as indicated by U-Pb ages of metamorphic monazites. Exhumation of the High Himalayan Slab was achieved through a combination of extensional unroofing along major detachments (namely the Zanskar Shear Zone), thermal doming, thrusting along the Main Central Thrust and surface erosion. Exhumation is closely associated with the growth of sillimanite- and cordierite-bearing assemblages in pelites and the generation and emplacement of crustal melt leucogranites in the upper parts of the slab. U-Pb dating of accessory phases from one of the crustal melt leucogranites (the Gumburanjon leucogranite) constrains its crystallisation and emplacement age at c.21-22 Ma. This is only slightly older than its ⁴⁰Ar/³⁹Ar muscovite and biotite cooling ages of c.20-21 Ma, which is attributed to the emplacement of the Gumburanjon leucogranite into the immediate footwall of the ZSZ. Field and geochronological data therefore support a strong temporal and spatial relationship between upper crustal melting and extension in a convergent orogen.

2 v. : ill. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Minerology, 1972