A new tetragonal silicate mineral occurring as inclusions in lower-mantle diamonds
Article Abstract:
Aluminium is one element in a group that forms the bulk of the Earth's mantle. Al, in the upper mantle, is mostly contained in minerals with a garnet structure, but there is uncertainty about the mineral transformations linked to garnet structures in the uppermost lower mantle. The discovery of a new aluminous mineral in lower mantle diamonds in Brazil is described. The structure is distinctly tetragonal and is referred to as tetragonal almandine-pyrope phase (TAPP). TAPP may be significant in determining density differences.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1997
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Experimental evidence for the origin of lead enrichment in convergent-margin magmas
Article Abstract:
Piston-cylinder experiments conducted at 900 degrees celsius and 2.0 GPa reveal that the generation of subduction zone magmas from mantle sources fluxed by basalt-derived fluid results in the addition of lead-rich, cerium-deficient, mantle-released substance to the continent. The continuing process of lead augmentation to Earth's continental crust is occurring at convergent margins. The mineral/fluid coefficients of rare earth element cerium is measured and is found to be independent of concentration.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1995
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Extreme crustal oxygen isotope signatures preserved in coesite in diamond
Article Abstract:
The oxygen isotope composition of eclogite mineral inclusion, analyzed in situ in diamonds, is presented. The oxygen isotope values of coesite, a Polymorph of SiO2, inclusions are substantially higher than previously reported for xenoliths from the subcratonic mantle.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 2003
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