The osmium isotopic composition of the Earth's primitive upper mantle
Article Abstract:
A value for the osmium isotopic composition of the modern 'primitive upper mantle' (PUM), a hypothetical undifferentiated upper-mantle reservoir, is reported. A minimum (super 187)Os/(super 188)Os ratio for PUM of 0.1290 +/- 0.0009 is derived from suites of melt-depleted mantle xenoliths from three continents through a correlation between (super 187)Os/(super 188)Os and geochemical indices of 'fertility' to extrapolate to the Os isotope ratio of undepleted mantle. A comparison with the (super 187)Os/(super 188)Os ratios in different classes of chrondritic meteorite leads to the conclusion that the late veneer has siderophile element abundances similar to those of enstatite or ordinary chrondrites.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
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Geochemical evidence for melt migration and reaction in the upper mantle
Article Abstract:
Geochemical analysis of the Horoman peridotite complex in Hokkaido in northern Japan provides further details of the melt segregation that influenced the chemical evolution of the Earth's crust and mantle. The Horoman complex, which consists of layered upper-mantle rock, contains chondrite-normalized rare-earth element patterns that probably resulted from chromatographic fractionation as melts moved upward and produced compositional heterogeneities in the upper mantle by interacting with peridotite. These heterogeneities augmented other geochemical processes that produced melts.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1992
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The Earth's mantle
Article Abstract:
Research describing the composition and structure of the Earth's mantle is presented. In particular analysis of heat-flow, geochemical and seismological data is used to support a whole mantle convection theory.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 2001
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