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Showing 1 to 20 of 295 for “"metamorphism"”.
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Mineral ages and metamorphism
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Geology and Geophysics, 1960.
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Metamorphism of the Troodos Massif, Cyprus
… at a constructive plate margin. Here, the metamorphism and geochemistry of the dyke/pillow lava sequence at the top of the igreous succession are shown to be compatible with this proposal. The greater part of the sequence is basaltic and is divided by a metamorphic discontinuity near the …
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Studies in mass transport in contact metamorphism,
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Geology and Geophysics, 1968.
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Metamorphism in the Northern Front Range, Colorado
… by both blocks. Both blocks experienced peak metamorphism within the sillimanite-K-feldspar zone accompanied by partial melting, are characterized by stromatic migmatites, and show textural evidence for localized reactions related to decompression and cooling. Differences between the blocks …
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Salobo Sequence, Carajas, Brazil: Geology, Geochemistry And Metamorphism
… Cu.;The Salobo sequence underwent progressive metamorphism close to pyroxene hornfels facies, followed by two episodes of hydrothermal alteration, at amphibolite and greenschist facies. The first metamorphic episode took place at low pressure (2-3 kbar) with a temperature of …
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Archean metamorphism in northwestern Ontario and southeastern Manitoba
<p> Four areas are considered in this study. In Ontario, north-south traverses were made along Highway 599 between Savant Lake and Central Patricia, along the Vermilion River road (40 kilometers northeast of Sioux Lookout) and along Highway 105 between Vermilion Bay and Ear Falls (Fig. 3). The …
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Contact metamorphism of the Lucerne pluton, Hancock Co., Maine
… pressure between 1000 and 3000 bars during metamorphism with temperatures between 700°C and 450°C. Isobaric univariant assemblages in the calc-silicate beds indicate buffering of H₂O/CO₂ fluids produced by prograde reactions. H₂O rich fluids that produced zoisite were probably associated …
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The stratigraphy and metamorphism of the Snyder Group, Labrador
… undergone deformation and a medium to high grade metamorphism as the result of the emplacement of the Elsonian Kiglapait intrusion. Five lithostratigraphic units totaling 239 m in thickness have been recognized: (1) a lower quartz arenite with local arkosic arenites, pelites, conglomerates, and a …
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The timing of prograde metamorphism in the Garhwal Himalaya, India
… obtained from garnets indicate that prograde metamorphism occurred during crustal thickening and "peak" thermobarometric estimates show that the presently exposed HHCS records temperatures of -700 °C throughout the section accompanied by a decrease in pressures from --13 kbar at the base to -6 …
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Unrecognized complexities of metamorphism : crystallization kinetics, reaction affinity, and geochronology
… pressure-temperature conditions during regional metamorphism are based on the assumption of chemical equilibrium, and geochronology in metamorphic rocks can suffer from cryptic redistribution of isotopes. In this research, the scales of disequilibrium in regionally metamorphosed rocks and the …
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On Ultra-High Temperature Metamorphism in the Mid-Lower Crust
… contribute to the understanding of UHT metamorphism in the Earth's crust. This work focuses on the development of hybrid monzonorites and emery at Salt Hill, located in the southeasternmost edge of the Cortlandt Complex. First, a thermobarometric study focuses on the P-T conditions of …
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High pressure acadian metamorphism of the Straits Schist, Western Connecticut
… Vermont, respectively. Furthermore, the age of metamorphism is interpreted as being Acadian based on the proposed age and stratigraphy, simple metamorphic textures, and uniform grain sizes. Quantitative estimates of the pressure and temperature conditions under which the mineral assemblages of …
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Polyphase deformation and metamorphism in the Penobscot Bay Area, Coastal Maine
… (D₁, D₂, D₃, and D₄) and interdeformational metamorphism and granitic plutonism. D₁ (early Acadian ?) produced tight to isoclinal folds and an axial plane foliation that deform all three metasedimentary units and contacts between these units. These units and therefore the PGW and Bucksport …
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The structure and metamorphism of the Santa Marta area, Colombia, South America
… The Concha Formation has suffered retrograde metamorphism under high PCO2 conditions which account for the general absence of Ca-amphibole and the abundance of chlorite + carbonate assemblages. Local occurrences of coarse grained amphibole schists radiometrically determined to be Cretaceous in …
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Structural geology, metamorphism and origin of the Kanmantoo Copper deposit, South Australia
On the basis of the present study it is concluded that there is no firm evidence that the bulk of the mineralisation is pre-metamorphic, although the possibility has not been excluded.
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