GROWTH FORMS AND COMPOSITION OF CHROMIAN SPINEL IN MORB MAGMA: DIFFUSION-CONTROLLED CRYSTALLIZATION OF CHROMIAN SPINEL
نویسندگان
چکیده
منابع مشابه
Chromian spinel–olivine phase chemistry and the origin of primitive basalts of the southern Washington Cascades
Geochemically diverse basalts occur in an ~160-km-wide transect that stretches across the Quaternary southern Washington Cascades (SWC) volcanic arc. Two fundamental groups of SWC basalts can be identified on the basis of major and trace element chemistry. On primitive mantle-normalized “spidergrams”, Group I lavas resemble within-plate basalts, whereas Group II lavas exhibit chemical character...
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Archaean komatiites of the greenstone belt in Manica area, western Mozambique contains accessory amount of disseminated chromite grains. The komatiite rocks comprise peridotitic and basaltic komtiite. These komatiites are affected by regional metamorphism as all of the studied area. It is observed that only chromian spinel is preserved as the primary mineral and that all the other primary miner...
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In the upper Proterozoic Anarak ophiolite, the marbles are present and havr excellent exposures in different areas. Their best exposure is in southern slope of Chah-Gorbeh mountain (Chah-Mahdi valley). In the field, marbles have massive and dike like exposures. Petrographic studies and geochemistry of minerals show that marbles consist of carbonate (calcite), garnet (andradite), clinopyroxene (...
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The Kermanshah ophiolite complex is located in outer Zagros ophiolitic belt and consists of both mantle and crustal suites as remnants of southern branch of the Neo-Tethys Ocean in Iran. Chemical composition determinative diagram of minerals indicates that olivine in dunite, harzburgite and lherzolites has forsteritic composition and in wherlitic rocks is chrysolite in composition likewise orth...
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Geologists usually deal with rocks that are up to several thousand million years old. They try to reconstruct the tectonic settings where these rocks were formed and the history of events that affected them through the geological time. The spinel group minerals provide useful information regarding the geological environment in which the host rocks were formed. They constitute excellent indicato...
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ژورنال
عنوان ژورنال: The Canadian Mineralogist
سال: 2001
ISSN: 0008-4476,1499-1261
DOI: 10.2113/gscanmin.39.2.397