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Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.14/170614
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- Title
- Late metasomatic addition of garnet to the SCLM : Os-isotope evidence
- Related
- Goldschmidt Conference (21st : 2011) (14 - 19 August 2011 : Prague, Czech Republic)
- Related
- Mineralogical magazine, Vol. 75, No. 3, p.1395
- Related
- http://goldschmidt.info/2011/index.html
- Publisher
- London : Mineralogical Society
- Date
- 2011
- Author/Creator
- Malkovets, V. G
- Author/Creator
- Griffin, W. L
- Author/Creator
- Pearson, N. J
- Author/Creator
- Rezvukhin, D. I
- Author/Creator
- O'Reilly, S. Y
- Author/Creator
- Pokhilenko, N. P
- Author/Creator
- Garanin, V. K
- Author/Creator
- Spetsius, Z. V
- Author/Creator
- Litasov, K. D
- Description
- 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.
- Description
- 1 page(s)
- Resource Type
- conference paper abstract
- Organisation
- Macquarie University. National Key Centre for Geochemical Evolution and Metallogeny of Continents (GEMOC)
- Identifier
- http://hdl.handle.net/1959.14/170614
- Identifier
- ISSN:0026-461X
- Identifier
- mq-rm-2011006472
- Identifier
- mq_res-ext-pro885350945
- Language
- eng
Macquarie University ResearchOnline
