Contaminated komatiites
نویسندگان
چکیده
منابع مشابه
Thermal evolution of the Earth as recorded by komatiites
Komatiites are rare ultramafic lavas that were produced most commonly during the Archean and Early Proterozoic and less frequently in the Phanerozoic. These magmas provide a record of the thermal and chemical characteristics of the upper mantle through time. The most widely cited interpretation is that komatiites were produced in a plume environment and record high mantle temperatures and deep ...
متن کاملKomatiites: From Earth’s Geological Settings to Planetary and Astrobiological Contexts
Fodor, R.V. and Keil, K.: 1976, Earth Planet. Sci. Lett. 29, issue 1, 1-6.Francis, P. and Oppenheimer, C.: 2004, Extraterrestrial volcanoes. Volcanoes, second edition,Oxford University Press Inc., New York, pp. 392-393. Francis, D.: 2003, Lithos 71, 135-152.Frankel, C.: 1996, Martian volcanism in space and time. Volcanoes of the Solar System,Cambridge University Press, pp. 119-1...
متن کاملChromite composition as evidence of metamorphism in komatiites, greenstone belt, Mozambique
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...
متن کامل186Os^187Os systematics of Gorgona Island komatiites : implications for early growth of the inner core
The presence of coupled enrichments in 186Os/188Os and 187Os/188Os in some mantle-derived materials reflects longterm elevation of Pt/Os and Re/Os relative to the primitive upper mantle. New Os data for the 89 Ma Gorgona Island, Colombia komatiites indicate that these lavas are also variably enriched in 186Os and 187Os, with 186Os/188Os ranging between 0.11983977 22 and 0.11984707 38, and with ...
متن کاملHighly siderophile element geochemistry of Os-enriched 2.8 Ga Kostomuksha komatiites, Baltic Shield
New analyses of highly siderophile elements (HSE; Re, Os, Ir, Ru, Pt, and Pd) obtained by Carius tube digestion isotope dilution inductively coupled plasma mass-spectrometry (ID-ICPMS) technique are reported for Os-enriched 2.8 Ga komatiites from the Kostomuksha greenstone belt. As a result of a significant improvement in the yield over our previous digestions by the NiS fire-assay technique, t...
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ژورنال
عنوان ژورنال: Nature
سال: 1985
ISSN: 0028-0836,1476-4687
DOI: 10.1038/313247a0