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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 80 for “"greenschist"”.
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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 grade on a regional scale from lower greenschist facies in the outer perimeter of the Potchefstroom syncline, throughupper greenschist and amphibolite grades within rocks of the Witwatersrand Supergroupand Dominion Group in the collar of the Vredefort dome, to granulite grades in the …
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Polyphase deformation and metamorphism in the Penobscot Bay Area, Coastal Maine
… mineral elongation lineation under upper greenschist to lower amphibolite conditions. D₃ ductile strike-slip shear zones formed under upper greenschist to lower amphibolite conditions, and D₄ open, steeply-reclined folds formed under greenschist facies conditions. D₃ and D₄ are probably …
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P-T-t-d evolution paths within the Gander Zone, NE Newfoundland
… narrow high strain zones. S4WES~amphibolite to greenschist facies shear fabrics (predominantly dextral) overprint prograde fabrics (S3WEST)within domain 2 and are cross-cut by the c. 427 Ma Middle Brook Granite, Locally in domains 3 and 4 prograde (D3EAsT) fabrics are overprinted by amphibolite …
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Kinematics and timing of the Pinto shear zone, New York Mountains, northeastern Mojave Desert, California
… temperatures, from lower amphibolite-uppermost greenschist through lower greenschist facies conditions. The decrease in temperature of deformation probably occurred during progressive deformation. (Abstract shortened by UMI.).
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The Fries Fault near Riner, Virginia: an example of a polydeformed, ductile deformation zone
… altered basement rocks from lower amphibolite to greenschist facies. Chilhowee Group rocks remained at lower greenschist facies. Post-faulting deformation produced an S₃ crenulation cleavage associated with northeast trending, overturned F₃ folds. Subsequent refolding produced open, northwest …
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Tectogenesis of the Hylas zone and eastern Piedmont near Richmond, Virginia
… which initiated retrograde metamorphism to greenschist facies, carried an allochthonous plate of coarse-grained, locally porphyry tic Petersburg(?) Granite over a layered sequence of metamorphosed sedimentary and volcanic rocks now represented by biotite gneiss, biotite schist and …
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Ο ΠΛΟΥΤΩΝΙΤΗΣ ΤΗΣ ΜΑΡΩΝΕΙΑΣ ΚΑΙ Η ΜΕΤΑΜΟΡΦΙΚΗ ΤΟΥ ΕΠΙΔΡΑΣΗ ΣΤΑ ΠΕΡΙΒΑΛΛΟΝΤΑ ΠΕΤΡΩΜΑΤΑ ΤΗΣ ΦΥΛΛΙΤΙΚΗΣ ΣΕΙΡΑΣ
… OF MARBLES, CALCAREOUS PHYLLITES, GNEISSES, GREENSCHISTS, MICA SCHISTS, AND QUARTZITES. THESE ROCKS HAD UNDERGONE REGIONAL METAMORPHISM BELONGING TOTHE GREENSCHIST FACIES. (SHORTENED)
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Tectonic and geologic development of the Charlotte belt south central Virginia Piedmont
… grade gneisses, whereas the slate belt is at greenschist grade. The major results of the study are as follows: (1) The Carolina slate belt units, the Hyco Formation and the Aaron Formation, are present in the Charlotte belt, and a correlation between the two belts has been made. (2) The …
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Geology of the Humpback Mountain area of the Blue Ridge in Nelson and Augusta counties, Virginia
… granulite facies, retrograded to as low as the greenschist facies, and deformed into a series of east-trending folds prior to Late Precambrian. The relationships between the two metamorphic events and structural deformation was not determined. An angular unconformity separates the Catoctin Group …
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Petrology and contact relationships, SW portion PC Mullen Creek mafic complex, Medicine Bow Mts., Wy.
… fractures, veinlets and minerals typical of the greenschist facies such as chlorite, epidote, talc, serpentine and saussurite.
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Geodynamic evolution and petrogenesis of the neoarchaean Francistown granite-greenstone complex in NE Botswana, SW margin of the Zimbabwe craton
… rocks and mafic intrusions have undergone greenschist to lower amphibolite facies metamorphism, but most mafic intrusions have preserved original igneous textures. The Francistown Granite Greenstone Complex likely represents an arc complex that developed along an active continental margin …
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Petrology of Metadiabase Intrusions in the White Rock Quadrangle, Western North Carolina
… to the chlorite and biotite zones of the greenschist facies during the early or middle Paleozoic. The degree of metamorphic alteration varies both from one body to another and within an individual body. However, there does not appear to be any regular pattern of gradation within a …
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The structural setting of the Canaã dos Carajás region and Sossego-Sequeirinho deposits, Carajás – Brazil
… overprinted by deformation at middle to upper greenschist facies conditions (~400-500°C). The Canaã dos Carajás region represents part of an original granite-greenstone terrane that has undergone substantial reworking during a late sinistral transpressional deformation. The reworking took place …
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Structural geology of the southern Silurian hills, San Bernardino County, Calif
… acidic plutonic rocks. Metamorphism reaches high greenschist to low amphibolite grade with an overprint of contact metamorphism caused by the intrusion of the acidic plutonic rocks. The Riggs thrust fault separates the Pahrump Group, which is in the lower plate, from all of the other units. The …
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Aspects of the geochemistry of Onverwacht Group lavas from the Barberton Greenstone Belt
… phases have usually been reconstituted to greenschist facies mineral assemblages. Although original phenocryst phases are often pseudomorphed, they can still be identified from occasionally preserved relict grains and from the secondary mineral assemblages. In this way all the major phases …
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Effects of metamorphism and structure on aeromagnetic anomalies over the Carolina slate belt near Roxboro, North Carolina
… the subsurface configuration of a magnetized greenschist facies metasedimentary unit in the faulted core of the Virgilina synclinorium. Magnetic anomalies appear to be caused by the entire fold structure in some locations and by only the upper limbs of the structure in others. Two alternative …
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Banded metasiltstones in Trigo Canyon : the story they tell about the Proterozoic deformational history of the Manzano Mountains
… southeast were thrust west and north on top of greenschist-grade rocks to the north (top to the northwest). Thrusting probably took place between 1.656 billion years and 1.427 billion years ago, as shown by available geochronology in the Monte Largo thrust zone. This thesis involves field and …
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Geochemistry and origin of the Asimotrypes carbonate hosted mesothermal gold deposit, Pangeon mountain, N. Greece
… of U. Cretaceous - M. Eocene age, reached upper greenschist to lower amphibolite conditions. A low-pressure greenshist fades retrograde overprint during uplift marked the end of Alpine metamorphism in the Miocene. Post-metamorphic Miocene uplift has been recognised in the Pangeon Mt and it was …
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Petrography of Precambrian iron formation, Pembina County, North Dakota
… Akra site contained mineral assemblages of the greenschist and amphibolite facies of regional metamorphism, the metamorphic grade increasing with depth. The mineral assemblages of the Hensel core indicate amphibolite facies metamorphism. The Precambrian rocks of eastern North Dakota represent …
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Determining the physico-chemical conditions on the early earth : Barberton scientific drilling project, South Africa
… rocks are sparse and the nature of greenschist facies metamorphism is poorly characterized. In addition, alteration and silicification associated with distinct emerald green, fuchsite-(Crmica)- carbonate-quartz alteration zones is commonly found beneath chert horizons in the …
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