Diamondiferous eclogites from Yakutia, Siberia: evidence for a diversity of protoliths
Article Abstract:
Electron microprobe and secondary ion mass spectrometer (SIMS) detect the major-element and REE compositions of 14 diamondiferous eclogites from the Udachnaya kimberlite in Yakutia, Siberia. Differences in the nature of the source material and the processes are found between the Siberian and the South African eclogites. LREE depletions are shown by many reconstructed REE compositions. Some depletions need material of eclogitie or pyroxenitic affinities to undergo partial melting, which leads to the depletion of LREE, and the HREE are left at the original levels. Other depletions conform to the origin of normal or Type I ocean floor basalt. In South Africa, many eclogites are consistent with a protolith of 'anomalous' or Type II ocean floor basalt.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1993
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Exsolution of garnet within clinopyroxene of mantle eclogites: major- and trace-element chemistry
Article Abstract:
An examination of clinopyroxene and garnet of eclogite xenoliths from kimberlites at Bellsbank, South Africa, and Obnazherraya, Russia, is conducted to study the rare earth elements (REE) in eclogites showing garnet exsolution from clinopyroxene. Various compositions of the major- and the trace-elements are revealed. SIMS determines the REE concentrations of pyroxene and garnet. The REE patterns vary slightly from those of eclogites that do not have garnet exsolution textures. All three eclogite groups contain exsolved samples, and since samples with exsolution and those without are very different chemically, the variation between the two sets is mainly textural.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1993
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Comment on "Trace-element crystal chemistry of mantle eclogites" by F.A. Caporuscio and J.R. Smith
Article Abstract:
An alternative interpretation on the crystal chemistry of eclogites was presented to disprove arguments which cited high-pressure igneous accumulations of hyperaluminous pyroxene as evidence for a mid oceanic ridge basalt-like melt for kyanite bearing mantle eclogites. Trace element and rare earth element compositions were determined for samples from the Bellbank eclogite suite of South Africa. Results of the study confirmed that eclogites were not formed by igneous fractionation of hyperaluminous clinopyroxene.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1993
User Contributions:
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