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Diamonds from the asthenosphere and the transition zone

Thomas Stachel
Diamonds from the asthenosphere and the transition zone
European Journal of Mineralogy (October 2001) 13 (5): 883-892

Abstract

The evidence for diamond formation in the asthenosphere and the transition zone of the Earth's mantle rests exclusively on the observation of syngenetic inclusions of majorite garnet in diamond. A review of the compositions of these garnets shows them to have eclogitic chemistries. It is speculated that sublithospheric eclogitic diamonds originated in subducted oceanic crust which is relatively oxidized compared to pyrolitic mantle due to sea-water alteration. In such a scenario diamonds may originate either from redox reactions involving reduced mantle fluids and slab material or from reduction of carbonates which invariably occur with increasing depth as P promotes the formation of ferrous iron rich minerals and therefore decreasing fO (sub 2) .


ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 13
Serial Issue: 5
Title: Diamonds from the asthenosphere and the transition zone
Author(s): Stachel, Thomas
Affiliation: Institut fuer Mineralogie, Frankfurt, Federal Republic of Germany
Pages: 883-892
Published: 200110
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 76
Accession Number: 2001-075364
Categories: Geophysics of minerals and rocks
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2020, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
Update Code: 200123
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