Diamond, subcalcic garnet, and mantle metasomatism: Kimberlite sampling patterns define the link

Research Article| April 01, 2007 Diamond, subcalcic garnet, and mantle metasomatism: Kimberlite sampling patterns define the link V.G. Malkovets; V.G. Malkovets 1Geochemical Evolution and Metallogeny of Continents, Australian Research Council National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, Sydney, NSW 2109, Australia and Institute of Mineralogy and Petrography, Siberian Branch Russian Academy of Sciences, Novosibirsk 630090, Russia Search for other works by this author on: GSW Google Scholar W.L. Griffin; W.L. Griffin 2Geochemical Evolution and Metallogeny of Continents, Australian Research Council National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, Sydney, NSW 2109, Australia Search for other works by this author on: GSW Google Scholar S.Y. O'Reilly; S.Y. O'Reilly 2Geochemical Evolution and Metallogeny of Continents, Australian Research Council National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, Sydney, NSW 2109, Australia Search for other works by this author on: GSW Google Scholar B.J. Wood B.J. Wood 2Geochemical Evolution and Metallogeny of Continents, Australian Research Council National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, Sydney, NSW 2109, Australia Search for other works by this author on: GSW Google Scholar Author and Article Information V.G. Malkovets 1Geochemical Evolution and Metallogeny of Continents, Australian Research Council National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, Sydney, NSW 2109, Australia and Institute of Mineralogy and Petrography, Siberian Branch Russian Academy of Sciences, Novosibirsk 630090, Russia W.L. Griffin 2Geochemical Evolution and Metallogeny of Continents, Australian Research Council National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, Sydney, NSW 2109, Australia S.Y. O'Reilly 2Geochemical Evolution and Metallogeny of Continents, Australian Research Council National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, Sydney, NSW 2109, Australia B.J. Wood 2Geochemical Evolution and Metallogeny of Continents, Australian Research Council National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, Sydney, NSW 2109, Australia Publisher: Geological Society of America Received: 14 Jun 2006 Revision Received: 19 Nov 2006 Accepted: 27 Nov 2006 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2007) 35 (4): 339–342. https://doi.org/10.1130/G23092A.1 Article history Received: 14 Jun 2006 Revision Received: 19 Nov 2006 Accepted: 27 Nov 2006 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation V.G. Malkovets, W.L. Griffin, S.Y. O'Reilly, B.J. Wood; Diamond, subcalcic garnet, and mantle metasomatism: Kimberlite sampling patterns define the link. Geology 2007;; 35 (4): 339–342. doi: https://doi.org/10.1130/G23092A.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract A genetic relationship between diamond and subcalcic Cr-pyrope garnet, both being produced by a metasomatic process, can be inferred from the sampling patterns of kimberlites in the Daldyn-Alakit province, Yakutia, Russia. Pressure-temperature estimates for xenoliths and xenocrysts show a strong concentration of highly depleted rocks in a well-defined zone 140–190 km deep; diamond inclusions and diamond-bearing xenoliths show that most diamonds come from harzburgites within this layer. Xenocryst distribution curves indicate that diamondiferous kimberlites have sampled both garnet and chromite from the harzburgitic layer, but low-grade pipes have sampled only chromite. Diamond formation probably is due to the oxidation of methane-rich, silica-bearing fluids: Fe2O3 (in chromite) + CH4 → C + H2O + FeO (in chromite), accompanied by another reaction: chromite ± olivine ± orthopyroxene + Si, Ca (in fluid) → low-Ca, high-Cr garnet. The presence or absence of diamond in kimberlites thus reflects the distribution of metasomatized fluid conduits in a lithospheric mantle that originally consisted of highly refractory harzburgites containing neither garnet nor diamond. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.