Diamond-graphite relationships in ultrahigh-pressure metamorphic rocks from the Kokchetav Massif, northern Kazakhstan

Korsakov, AV; Perraki, M; Zedgenizov, DA; Bindi, L; Vandenabeele, P; Suzuki, A; Kagi, H

dc.contributor.author	Korsakov, AV	en
dc.contributor.author	Perraki, M	en
dc.contributor.author	Zedgenizov, DA	en
dc.contributor.author	Bindi, L	en
dc.contributor.author	Vandenabeele, P	en
dc.contributor.author	Suzuki, A	en
dc.contributor.author	Kagi, H	en
dc.date.accessioned	2014-03-01T01:33:09Z
dc.date.available	2014-03-01T01:33:09Z
dc.date.issued	2010	en
dc.identifier.issn	0022-3530	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/20348
dc.subject	Diamond	en
dc.subject	Graphite	en
dc.subject	Kokchetav Massif	en
dc.subject	Metastable growth	en
dc.subject	Raman spectroscopy	en
dc.subject	UHP metamorphism	en
dc.subject.classification	Geochemistry & Geophysics	en
dc.subject.other	clinopyroxene	en
dc.subject.other	diamond	en
dc.subject.other	garnet	en
dc.subject.other	graphite	en
dc.subject.other	graphitization	en
dc.subject.other	inclusion	en
dc.subject.other	kyanite	en
dc.subject.other	metamorphic rock	en
dc.subject.other	Raman spectroscopy	en
dc.subject.other	scanning electron microscopy	en
dc.subject.other	ultrahigh pressure metamorphism	en
dc.subject.other	X-ray diffraction	en
dc.subject.other	Kazakhstan	en
dc.subject.other	Kokchetav Massif	en
dc.title	Diamond-graphite relationships in ultrahigh-pressure metamorphic rocks from the Kokchetav Massif, northern Kazakhstan	en
heal.type	journalArticle	en
heal.identifier.primary	10.1093/petrology/egq001	en
heal.identifier.secondary	egq001	en
heal.identifier.secondary	http://dx.doi.org/10.1093/petrology/egq001	en
heal.language	English	en
heal.publicationDate	2010	en
heal.abstract	Graphite inclusions in diamond, K-bearing clinopyroxene, garnet and kyanite and graphite coatings around microdiamonds from the ultrahigh-pressure Kokchetav Massif, northern Kazakhstan were investigated by means of scanning electron microscopy, laser Raman spectroscopy and X-ray diffraction. Important observations include the increasing size of the graphite crystals from the diamond-graphite interface to the external part of the graphite coatings, the high volume fraction of graphite in the graphite coatings, the presence of composite crystals of successively formed diamond core-graphite mantle zone-diamond rim-external graphite coating, the spherulitic texture of the graphite coatings, the formation of both ordered and disordered graphite and the absence of any fluid associated with the graphite inclusions in diamond and other ultrahigh-pressure metamorphic (UHPM) minerals. These features combined with the presence of oriented graphite flakes in K-bearing clinopyroxene and in diamond-bearing garnet and kyanite and the presence of intergranular diamonds without graphite coatings in the quartzo-feldspathic matrix require reconsideration of the generally accepted diamond graphitization model for interpreting the formation of graphite in UHPM rocks. Metastable growth of graphite within the diamond stability field is suggested and the following crystallization scheme for the C-polymorph is proposed: graphite was the first C-polymorph formed in the diamond stability field, followed by diamond; the graphite coatings around diamond formed during the final stage of UHPM conditions. © The Author 2010. Published by Oxford University Press.	en
heal.publisher	OXFORD UNIV PRESS	en
heal.journalName	Journal of Petrology	en
dc.identifier.doi	10.1093/petrology/egq001	en
dc.identifier.isi	ISI:000274500700007	en
dc.identifier.volume	51	en
dc.identifier.issue	3	en
dc.identifier.spage	763	en
dc.identifier.epage	783	en