Results 171 to 180 of about 297,462 (204)
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Geochemistry of Archaean Metavolcanic Rocks from the Kudremukh Area, Karnataka
Journal Geological Society of India, 1981Abstract Major and trace element data for metabasaits and metaperidotites from the littleknown Archaean volcanic-sedimentary belt at Kudremukh are presented. The dominant rocks are low K tholeiites showing evidence of partial melting from a Zr, Y and Nb enriched, P and Ta depleted mantle source, at depths where garnet was stable in ...
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Scottish Journal of Geology, 1993
Synopsis A detailed petrological and geochemical study of metavolcanic schists of the Dalradian Argyll Group of the southern Highlands of Scotland reveals the activity of five main centres of volcanicity. Volcanic activity started with the localized eruption of low HFSE tholeiites comprising the Laoigh Metabasites during the deposition of the
S. Goodman, J. A. Winchester
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Synopsis A detailed petrological and geochemical study of metavolcanic schists of the Dalradian Argyll Group of the southern Highlands of Scotland reveals the activity of five main centres of volcanicity. Volcanic activity started with the localized eruption of low HFSE tholeiites comprising the Laoigh Metabasites during the deposition of the
S. Goodman, J. A. Winchester
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Steep tilting of metavolcanic rocks by multiple mechanisms, central Sierra Nevada, California
Geological Society of America Bulletin, 2000For ∼200 km along the eastern Sierra Nevada continental magmatic arc, Mesozoic metavolcanogenic rocks dip steeply to the southwest (∼80°), a feature that must reflect fundamental processes in magmatic-arc construction. Although tight folds can account for such steep bedding tilts, folds in the metavolcanogenic sections are sparse and small scale.
Tobisch, Othmar T. +4 more
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Petrography and Geochemistry of the North of Ilgin (Konya) Metavolcanic Rocks
In this study, investigated the geology, mineralogy, petrography and geochemistry of metavolcanic rocks in northern Ilgın (Konya). There are two Paleozoic and Mesozoic metamorphic rock groups in the study area. Alluvium and Neogene sediments are unconformably layered over these rocks.Oral Sarıkaya, Şenel Özdamar
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Canadian Journal of Earth Sciences, 1977
Base metal and gold ores in thin calc-silicate and cordierite gneiss units at Montauban-Les-Mines have historically been described as pyrometasomatic deposits related to granitic intrusions. They are stratigraphically overlain by quartzo–feldspathic gneiss and amphibolite, the uppermost amphibolite unit being a pillowed metabasalt.Chemical analysis ...
Karen Stamatelopoulou-Seymour +1 more
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Base metal and gold ores in thin calc-silicate and cordierite gneiss units at Montauban-Les-Mines have historically been described as pyrometasomatic deposits related to granitic intrusions. They are stratigraphically overlain by quartzo–feldspathic gneiss and amphibolite, the uppermost amphibolite unit being a pillowed metabasalt.Chemical analysis ...
Karen Stamatelopoulou-Seymour +1 more
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U-Pb and Th-Pb whole-rock isochrons from metavolcanic rocks of the Carolina slate belt
Geological Society of America Bulletin, 1987Felsic volcaniclastic rocks and massive pyrite of a part of the Carolina slate belt in South Carolina referred to as the “Haile-Brewer block” seem to have remained closed systems with respect to U, Th, and Pb since ∼465 Ma. U-Pb and Th-Pb whole-rock isochrons indicate ages of 466 ± 40 (2σ) and 462 + 53 Ma, respectively. The Pb-Pb secondary isochron age
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Geological Society, London, Special Publications, 1987
Summary The dominantly metavolcanic Issineru Formation (IF) forms the lower 5–7 km of the stratotype for the early Proterozoic Mazaruni greenstone belt, N Guyana. Basalts and gabbros comprise the lower part of the section. The upper half includes some basalts, but is predominantly intermediate and felsic rocks.
R. Renner, A. K. Gibbs
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Summary The dominantly metavolcanic Issineru Formation (IF) forms the lower 5–7 km of the stratotype for the early Proterozoic Mazaruni greenstone belt, N Guyana. Basalts and gabbros comprise the lower part of the section. The upper half includes some basalts, but is predominantly intermediate and felsic rocks.
R. Renner, A. K. Gibbs
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Sm-Nd Isotopic Data from Archean Metavolcanic Rocks at Holenarsipur, South India
The Journal of Geology, 1987Results of a Sm-Nd isotopic analysis of Archean metavolcanics in the Holenarsipur greenstone belt, Karnataka, South India, give a whole-rock isochron age of 2.62 Ga for lightly deformed metabasaltic amphibolites in the northern part of the belt. This is within error of the age of high-grade metamorphism and crustal thickening which affected areas ...
S. A. Drury +2 more
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Economic Geology, 1985
West Shasta district bimodal volcanics (Copley Greenstone and Balaklala Rhyolite) are members of a low K calc-alkaline suite. They have rare earth element distributions characterized by pronounced light rare earth element depletion and unfractionated heavy rare earth elements. The striking similarities of the rare earth element patterns between the two
A. E. Bence, Bruce E. Taylor
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West Shasta district bimodal volcanics (Copley Greenstone and Balaklala Rhyolite) are members of a low K calc-alkaline suite. They have rare earth element distributions characterized by pronounced light rare earth element depletion and unfractionated heavy rare earth elements. The striking similarities of the rare earth element patterns between the two
A. E. Bence, Bruce E. Taylor
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The origin of metavolcanic and associated argillaceous rocks at Island Bay, Wellington, New Zealand
New Zealand Journal of Geology and Geophysics, 1985Abstract The alternating greywacke‐argillite turbidite beds exposed on the eastern side of Island Bay, Wellington, New Zealand, belong to the Torlessia fossil zone of the Torlesse Supergroup. They were deposited in a deep‐water marine environment.
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