Results 181 to 190 of about 1,706 (214)
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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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Metavolcanic rocks and their origin, Southern Adirondack mountains, New York
Bulletin Volcanologique, 1970One of the problems associated with massif-type anorthosite in high grade metamorphic terranes is the absence of anorthositic extrusives. However, if anorthosite formed by crystal segregation, volcanic equivalents of the final fluid differentiate might occur.
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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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Geochemistry of the Archaean Metavolcanic Rocks of Kolar and Hutti Gold Fields, Karnataka, India
Journal Geological Society of India, 1979Abstract Geochemical data on Archaean goldfields metavolcanics (2.7 b. yrs) have been plotted on major and minor element discriminant diagrams to define the magma type and to formulate the tectonic environment model for the origin of these ancient volcanic rocks.
Iyer, GVA, Vasudev, VN
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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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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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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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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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Canadian Journal of Earth Sciences, 1996
The Beardmore–Geraldton greenstone belt lies between the Wabigoon volcanic arc (Onaman–Tashota terrane) and the Quetico metasedimentary subprovince and thus has an important bearing on the accretionary model that has been proposed for the amalgamation of these terranes.
K. Y. Tomlinson +3 more
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The Beardmore–Geraldton greenstone belt lies between the Wabigoon volcanic arc (Onaman–Tashota terrane) and the Quetico metasedimentary subprovince and thus has an important bearing on the accretionary model that has been proposed for the amalgamation of these terranes.
K. Y. Tomlinson +3 more
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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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