Major-element variability in the Hawaiian mantle plume
Article Abstract:
The isotope ratios and major elements present in the shield-stage basaltic lavas from eight Hawaiian volcanoes, such as Loihi, Koolau and Loa, exhibit distinct correlated variations. The composition of this region is different from the usual mantle peridotite. The data indicate the presence of a solid mantle below Hawaii, probably formed from recycled oceanic crust. The crust may have been distributed within the Hawaiian plume as segregations of quartz-bearing garnet pyroxenite or eclogite. The segregations produce silica-rich magmas on partial melting.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
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Electrical conductivity of silicate perovskite at lower-mantle conditions
Article Abstract:
Laboratory conductivity measurements on silicate perovskite at high pressures give conflicting estimates of mantle conductivity. Measurements of electrical conductivity of perovskite in a multi-anvil press under appropriate conditions for the uppermost lower mantle, were undertaken. The conductivity of the perovskite part of a low-oxygen-fugacity mantle consisting of pyrolite explains the geophysical estimate of low-mantle electrical conductivity.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1998
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Non-chondritic platinum-group element ratios in the Earth's mantle
Article Abstract:
The high precision analyses of platinum-group elements (PGE) from upper-mantle lherzolites indicates that the Pd/Ir ratio, at 1.76, is considerably more than that of chonidritic meteorites. The mantle is heterogeneous in its PGE content, and the Pd and Rh content of the terrestrial mantle vary on the spatial scale up to nearly 100 km. The Pd/Rh ratio of undifferentiated meteorite is less than the Pyrenean lherzolites.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
User Contributions:
Comment about this article or add new information about this topic:
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