The Yale Creek area is underlain by the pelitic Settler Schist, Spuzzum hornblende quartz diorites, and minor gneiss and granodiorite. Mineral textures in the schists define three phases of folding. The structural geology is dominated by the second phase, f₂, characterized by northwest plunging isoclinal folds. Regional metamorphism reached its culmination just after f₂. The structurally concordant and broadly syn-tectonic Spuzzum intrusions were emplaced over a period of time encompassing the period of folding and regional metamorphism and served as a heat source for the regional metamorphism and early contact metamorphism. Late faulting has juxtaposed Settler Schist and Custer Gneiss across the Hope Fault, and Settler Schists of contrasting metamorphic grades across the Cogburn Creek Fault. A Triassic Rb-Sr date obtained for the Settler Schist is interpreted as the date of deposition of original—eugeosyclinal sedimentsHornblende K-Ar ages of 75.5±2.6 and 92.1±3.2 Ma obtained for Spuzzum quartz diorites conform to a regional east-younging trend in Spuzzum K-Ar ages which reflects the cooling history of the area rather than age of intrusive emplacement. The date of emplacement of the structurally discordant and post-tectonic body of granodiorite was defined as 32±2Ma by concordant Rb-Sr and K-Ar dates. The distribution of aluminosilicate assemblages in the Settler Schist defines three regional metamorphic zones increasing in grade to the north. The kyanite zone and two sillimanite zones are separated by two isograds which mark equilibrium and overstepped kyanite-sillimanite transitions. The metamorphic conditions near the first sillimanite iso- grad are estimated to be 705±45°C and 7.6±0.5kb from the mutual intersection of equilibria calculated from thermodynamic data and microprobe analyses. Anatectic relations established to date for pelitic systems appear to be inconsistent with, this thermodynamic P-T estimate. Mineral assemblages in scattered ultramafic pods are consistent with the metamorphic P-T estimates for the pelitic assemblages. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Unknown

Ordinary chondrites are the most common type of meteorite to fall to Earth and are composed of lithified primitive nebular materials which have experienced variable extents of thermal metamorphism and shock processing. They were subjected to radiogenic heating by incorporation of unstable short lived radionuclides such as 26Al in the early solar system. The relationship between metamorphism and impact processing in ordinary chondrites is not fully understood. An unresolved issue in the study of ordinary chondrites is whether their original parent bodies were fragmented by impacts into rubble-pile bodies while they were still hot, or whether they retained their onion-shell structures until they had shed their radiogenic heat. Heat is lost more quickly due to catastrophic impacts because warm material from the interior is exposed directly to the space environment until the impact debris re-accretes into a rubble-pile body, and is then distributed evenly between the surface and the interior of the new rubble-pile body. The extent of retrograde metamorphism possible in ordinary chondrites would therefore largely be dictated by the extent to which their parent bodies were broken up by impacts. Disaggregation caused by an impact would record fast cooling between the temperature at the time of breakup and the temperature at the time of re-accretion. In this thesis project, five H6 chondrites (Butsura, Estacado, Kernouve, Portales Valley, Queen's Mercy) and five L6 chondrites (Bruderheim, Holbrook, Leedey, Morrow County, Park) were subjected to three different thermometry analyses (pyroxene, olivine spinel, and metallographic) to determine their cooling profiles and evaluate same set of samples. Cooling rates for pyroxene and olivine--spinel thermometry systems are determined using the formulation of Dodson (1973) as modified by Ganguly & Tirone (1999). Cooling rates for the metallographic system are determined using the method developed by Wood (1967) as modified by Willis & Goldstein (1981). At temperatures higher than ~600 degrees C, all samples experienced cooling rates which are orders of magnitude faster (100's to 1000's of degrees C/kyr) than what is predicted for onion--shell thermal evolution (10's of degrees C/Myr) by e.g. Monnereau et al. (2013). At temperatures below ~600 degrees C, i.e. those recorded by the metals, cooling rates are much slower in comparison to the silicate/oxide systems, with the exception of Park, which continued to cool quickly. The discrepancy between high-- and low--temperature cooling rates for both H-- and L--chondrites can best be accounted for by a catastrophic impact which occurred while each body was still near its peak metamorphic temperature, followed by re--accretion into a rubble--pile, which would then cool slowly due to the poor thermal conductivity of rubble--piles. Shock heating does not appear to affect silicate--oxide thermometers.

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Includes copies of articles co-authored by author during the preparation of this thesis in back pocket. / Includes bibliographical references (leaves 113-124). / viii, 172 leaves : ill. (some col.), maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Focuses on the impact of change in the distribution of heat producing elements on lithospheric thermal regimes and on temperature dependent processes such as metamorphism, magmatism and deformation, with application to Proteozoic Australia (Mount Isa and Mount Painter inliers). / Thesis (Ph.D.)--Adelaide University, Dept. of Geology and Geophysics, 2001

"Two independent geochronological techniques specifically targeting post-kinematic or late-stage growth of kyanite, staurolite and late-stage garnet in the southern Curnamona Province has found that these minerals grew during the Delamerian Orogeny (~530-500 Ma). Prograde metamorphism during the Delamerian Orogeny attained kyanite-staurolite-garnet grade (amphibolite-facies). Previous interpretations of an anticlockwise P-T path for the Olarian Orogeny need revising, as these interpretations have been shown in this study to be based on textural relationships spanning ~1100 million years. This highlights the importance of in situ geochronological techniques in defining robust P-T-t paths for a region." --p. 121 of source document. / Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2006.

Thesis (M.S.)--University of Tennessee, Knoxville, 2010. / Title from title page screen (viewed on July 20, 2010). Thesis advisor: Robert D. Hatcher, Jr. Vita. Includes bibliographical references.

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Conditions of 8kb and 800°C are estimated for sillimanite K feldspar bearing metapelites and garnet-clinopyroxene bearing amnphibolites in Glen Muick. These conditions are inconsistent with the simultaneous nearby presence of equilibrium between andalusite and kyanite. Andalusite in the Glen Muick area is late. The sillimanite zone may have been in part primary. There is a transition without major structural break between Tay Nappe flat belt and the "Banff Nappe". A dataset has been derived for phases in the system KCMASHCO₂. The MHSRK equation of Kerrick and Jacobs (1981) has been used to extract data from mixed devolatilisation equilibria. Heats of formation are in agreement with calorimetrically determined values. Phlogopite equilibria calculated using disordered phlogopite data seem most appropriate to natural metapelite assemblages. Variations in pressure and temperature have been constrained across the Dalradian using various calibrated reactions. Temperatures vary from about 500°C in the low kyanite zone to 800°C in the sillimanite-K feldspar zone and pressures vary from 4kb to 10kb. Pressure estimates are justified on the basis that they are consistent with the aluminosilicate phase diagram. Rocks from the Central Highlands to Glen Clova underwent a decrease in pressure during evolution through peak metamorphic conditions. Amphibolites from the southern Moines show evidence of a former eclogitic assemblage of early Grampian age or earlier. High temperature regional metamorphic rocks lie at high structural levels and are are suggested to be an allochthonous unit, the Banff Nappe of Grampian age. The western margin of the Banff Nappe is marked by a temperature maximum to the immediate east, sharp thermal transitions, a train of metabasites and a high strain zone. It is suggested that emplacement of a Banff Nappe resulted in the deformation and metamorphism of structurally lower rocks.