Late metasomatic addition of garnet to the SCLM: Os-isotope evidence

V. G. Malkovets, W. L. Griffin, N. J. Pearson, D. I. Rezvukhin, S. Y. O'Reilly, N. P. Pokhilenko, V. K. Garanin, Z. V. Spetsius, K. D. Litasov

    Research output: Contribution to journalMeeting abstract


    Archean cratons are underlain by highly depleted subcontinental lithospheric mantle (SCLM). However, xenolith and xenocryst data [1; references therein] suggest that Archean SCLM has been extensively refertilized by metasomatic processes, with the addition of Fe, Ca, and Al to depleted protoliths. The distribution of sub-calcic garnets in the SCLM beneath the Siberian craton suggests (1) sub-calcic garnets and diamonds are metasomatic phases in the cratonic SCLM; (2) the distribution of both phases is laterally heterogeneous on relatively small scales and related to ancient structural controls [2]. Re-Os isotopic compositions of sulfide inclusions in lherzolitic Cr-pyropes from four Siberian middle Paleozoic diamond mines have been determined by laser ablation MC-ICP-MS: Mir (n=17) and Internationalnaya (n=109), Malobotuobiya field, Udachnaya (n=17), Daldyn field, and Nyurbinskaya (n=12), Nakyn field. Most analysed sulfides ( approximately 84%) have very low Re/Os ratios (<0.07), and their Re-depletion ages (T (sub RD) ) fall between 2.2 and 3.0 Ga (+ or -0.03 Ga, mean 2s analytical uncertainty). 10 to 15% of the sulfides give younger T (sub RD) down to 600 Ma. Our previous study [3] of sulfide inclusions in megacrystic olivines from the Udachnaya pipe suggests that most of the SCLM beneath the Daldyn kimberlite field formed at 3-3.5 Ga, and that lithosphere formation culminated at ca 2.9 Ga. Our new data suggest that refertilization of the highly depleted SCLM and the introduction of Cr-pyrope garnet occurred between 2.2 and 3.0 Ga; little garnet was present before 3 Ga. Pyropes with young sulfides (between approximately 1.9 and approximately 2.2 Ga) may have crystallised during the amalgamation of the Siberian craton in Paleoproterozoic time.
    Original languageEnglish
    Pages (from-to)1395
    Number of pages1
    JournalMineralogical Magazine
    Issue number3
    Publication statusPublished - 2011
    EventGoldschmidt Conference (21st : 2011) - Prague, Czech Republic
    Duration: 14 Aug 201119 Aug 2011


    Dive into the research topics of 'Late metasomatic addition of garnet to the SCLM: Os-isotope evidence'. Together they form a unique fingerprint.

    Cite this