Anticorrelation between low δ13C of eclogitic diamonds and high δ18O of their coesite and garnet inclusions requires a subduction origin

Title:
Anticorrelation between low δ13C of eclogitic diamonds and high δ18O of their coesite and garnet inclusions requires a subduction origin
Authors:
Schulze, Daniel J.; Harte, Ben; Page, F. Zeb ( 0000-0002-2100-0806 ) ; Valley, John W.; Channer, Dominic M. DeR.; Jaques, A. Lynton; Edinburgh Ion Microprobe Facility staff
Abstract:
Diamond is essentially impermeable and unreactive under many conditions, and tiny mineral inclusions within natural diamonds can faithfully preserve information on the chemical and physical conditions during diamond growth. The stable isotope ratios of carbon, nitrogen, oxygen, and sulfur in diamonds and their mineral inclusions have been used to constrain models of diamond formation, but interpretations of the data have differed dramatically. The crux of the controversy lies in the interpretation of the carbon isotope ratios of eclogite-suite diamonds, which range well outside those expected for typical mantle materials such as peridotites, basalts, and carbonatites. Proposed explanations for these anomalous carbon isotope ratios include derivation from primordial mantle inhomogeneities, fractionated mantle fluids, and subducted biogenic carbon. Working with samples from three continents, we have analyzed the carbon isotope compositions of eclogite-suite diamonds and the oxygen isotope composition of their mineral inclusions, primarily by ion microprobe methods. We have discovered a previously unrecognized, remarkably consistent anticorrelation between these two isotopic systems, in that virtually all diamonds with anomalously low carbon isotope ratios have silicate inclusions with anomalously high oxygen isotope ratios. This is a fundamental observation that can only be explained by formation of eclogite-suite diamonds through subduction of seafloor altered basalt, admixed with marine biogenic carbon, into the field of diamond stability.
Citation:
Schulze, Daniel J., Ben Harte, Edinburgh Ion Microprobe Facility staff, F. Zeb Page, et al. 2013. "Anticorrelation between low δ13C of eclogitic diamonds and high δ18O of their coesite and garnet inclusions requires a subduction origin." Geology 41(4): 455-458.
Publisher:
Geological Society of America
DATE ISSUED:
2013-02-20
Department:
Geology
Type:
Article
PUBLISHED VERSION:
10.1130/G33839.1
Additional Links:
http://geology.gsapubs.org/cgi/doi/10.1130/G33839.1
PERMANENT LINK:
http://hdl.handle.net/11282/594541

Full metadata record

DC FieldValue Language
dc.contributor.authorSchulze, Daniel J.en
dc.contributor.authorHarte, Benen
dc.contributor.authorPage, F. Zeben
dc.contributor.authorValley, John W.en
dc.contributor.authorChanner, Dominic M. DeR.en
dc.contributor.authorJaques, A. Lyntonen
dc.contributor.authorEdinburgh Ion Microprobe Facility staffen_US
dc.date.accessioned2016-01-21T19:38:53Zen
dc.date.available2016-01-21T19:38:53Zen
dc.date.issued2013-02-20en
dc.identifier.citationSchulze, Daniel J., Ben Harte, Edinburgh Ion Microprobe Facility staff, F. Zeb Page, et al. 2013. "Anticorrelation between low δ13C of eclogitic diamonds and high δ18O of their coesite and garnet inclusions requires a subduction origin." Geology 41(4): 455-458.en
dc.identifier.issn0091-7613en
dc.identifier.urihttp://hdl.handle.net/11282/594541en
dc.description.abstractDiamond is essentially impermeable and unreactive under many conditions, and tiny mineral inclusions within natural diamonds can faithfully preserve information on the chemical and physical conditions during diamond growth. The stable isotope ratios of carbon, nitrogen, oxygen, and sulfur in diamonds and their mineral inclusions have been used to constrain models of diamond formation, but interpretations of the data have differed dramatically. The crux of the controversy lies in the interpretation of the carbon isotope ratios of eclogite-suite diamonds, which range well outside those expected for typical mantle materials such as peridotites, basalts, and carbonatites. Proposed explanations for these anomalous carbon isotope ratios include derivation from primordial mantle inhomogeneities, fractionated mantle fluids, and subducted biogenic carbon. Working with samples from three continents, we have analyzed the carbon isotope compositions of eclogite-suite diamonds and the oxygen isotope composition of their mineral inclusions, primarily by ion microprobe methods. We have discovered a previously unrecognized, remarkably consistent anticorrelation between these two isotopic systems, in that virtually all diamonds with anomalously low carbon isotope ratios have silicate inclusions with anomalously high oxygen isotope ratios. This is a fundamental observation that can only be explained by formation of eclogite-suite diamonds through subduction of seafloor altered basalt, admixed with marine biogenic carbon, into the field of diamond stability.en
dc.language.isoen_USen
dc.publisherGeological Society of Americaen
dc.identifier.doi10.1130/G33839.1en
dc.relation.urlhttp://geology.gsapubs.org/cgi/doi/10.1130/G33839.1en
dc.subject.departmentGeologyen_US
dc.titleAnticorrelation between low δ13C of eclogitic diamonds and high δ18O of their coesite and garnet inclusions requires a subduction originen_US
dc.typeArticleen
dc.identifier.journalGeologyen
dc.subject.keywordCarbon isotopeen_US
dc.subject.keywordStable isotopesen_US
dc.subject.keywordOxygenen_US
dc.subject.keywordMantleen_US
dc.subject.keywordLithosphereen_US
dc.subject.keywordKimberlitesen_US
dc.subject.keywordBotswanaen_US
dc.subject.keywordOrapaen_US
dc.identifier.volume41en_US
dc.identifier.issue4en_US
dc.identifier.startpage455en_US
dc.rightsArchived with thanks to Geologyen
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