Geochemistry of kimberlites from the Nakyn field, Siberia: Evidence for unique source composition

Abstract

Research Article| March 01, 2001 Geochemistry of kimberlites from the Nakyn field, Siberia: Evidence for unique source composition A.M. Agashev; A.M. Agashev 1Institute of Mineralogy and Petrography, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk-90, Koptug street 3, Russia Search for other works by this author on: GSW Google Scholar T. Watanabe; T. Watanabe 2Department of Earth and Planetary Sciences, Graduate School of Sciences, Hokkaido University, Sapporo, Japan Search for other works by this author on: GSW Google Scholar D.A. Bydaev; D.A. Bydaev 3Institute of Mineralogy and Petrography, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia Search for other works by this author on: GSW Google Scholar N.P. Pokhilenko; N.P. Pokhilenko 3Institute of Mineralogy and Petrography, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia Search for other works by this author on: GSW Google Scholar A.S. Fomin; A.S. Fomin 4Botyobinskaya enterprise of Almazy Rossii-Sakha com., Mirny, Russia Search for other works by this author on: GSW Google Scholar K. Maehara; K. Maehara 5Department of Earth and Planetary Sciences, Hokkaido University, Sapporo, Japan Search for other works by this author on: GSW Google Scholar J. Maeda J. Maeda 5Department of Earth and Planetary Sciences, Hokkaido University, Sapporo, Japan Search for other works by this author on: GSW Google Scholar Geology (2001) 29 (3): 267–270. https://doi.org/10.1130/0091-7613(2001)029<0267:GOKFTN>2.0.CO;2 Article history received: 05 Jul 2000 rev-recd: 01 Dec 2000 accepted: 01 Dec 2000 first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation A.M. Agashev, T. Watanabe, D.A. Bydaev, N.P. Pokhilenko, A.S. Fomin, K. Maehara, J. Maeda; Geochemistry of kimberlites from the Nakyn field, Siberia: Evidence for unique source composition. Geology 2001;; 29 (3): 267–270. doi: https://doi.org/10.1130/0091-7613(2001)029<0267:GOKFTN>2.0.CO;2 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 Two newly discovered kimberlite pipes in the Nakyn field, Siberia yield Rb-Sr isochron ages of ca. 364 Ma, similar to emplacement ages of other major diamond-bearing pipes on the Siberian platform. Unlike any other Siberian kimberlites, however, the rocks from the Nakyn field show some similarities to South African group II (micaceous) kimberlites in their mineralogy and chemical compositions. Several key geochemical ratios (TiO2/K2O, 0.43; Nb/Zr, 0.4) in the Nakyn kimberlites are the same as for group II, whereas others such as Ba/Nb (0.95) and Ni/MgO (45.2) are intermediate between groups I and II, and La/Nb (0.58) ratios are similar to group I kimberlites.The Nakyn kimberlites are unique in having concentrations of incompatible elements two to three times lower than kimberlites from any cratonic area worldwide, coupled with higher Sm/Nd (0.21) and Lu/Hf (0.06) and lower La/Yb (25.8). Ranges of initial Sr and Nd isotope composition are very narrow in the Nakyn kimberlites, at ϵNd(t) +0.9 to −0.7 and 87Sr/86Sr(t) 0.7059–0.7068. These compositions are closer to group I than to group II kimberlites, but they require a source with higher Rb/Sr and lower Sm/Nd ratios than Group I kimberlites from both Siberia and South Africa. The trace element and isotope signatures of the Nakyn kimberlites appear to indicate a specific source located within the lithospheric mantle, distinct from that of other Siberian kimberlites. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.