RELATIONSHIP BETWEEN PLATINUM-BEARING ULTRAMAFIC-MAFIC INTRUSIONS AND LARGE IGNEOUS PROVINCES (exemplified by the Siberian Craton)
A.S. Mekhonoshin1,2, R.E. Ernst3,4, U. Söderlund5, M.A. Hamilton6, T.B. Kolotilina1,2, A.E. Izokh7,8, G.V. Polyakov7, N.D. Tolstykh7
1Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences, ul. Lermontova 83, Irkutsk, 664074, Russia
2Irkutsk Research Technical University
3Department of Earth Sciences, Carleton University, Ottawa, ON K1S 5B6, Canada
4Tomsk State University, ul. Lenina 36, Tomsk, 634050, Russia
5Lund University, 12 Sulvegatan, Lund, 223 62, Sweden
6J. Sutterlay Geochronology Laboratory, Toronto University, Toronto, ON N5S 3B1, Canada
7V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia
8Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090, Russia
Keywords: ЭПГ-Cu-Ni месторождения, ультрамафит-мафитовые интрузии, крупные изверженные провинции, PGE-Ni-Cu deposits, ultramafic-mafic intrusions, large igneous provinces
Abstract
This study aims at summarizing available geological and geochemical data on known Proterozoic platinum-bearing ultramafic-mafic massifs in the south of Siberia. Considering new data on geochemistry and geochronology of some intrusions, it was feasible to compare ore-bearing complexes of different time spans and areas and to follow their relationships with the recognized large igneous provinces. In the south of Siberia, the platinum-bearing massifs might be united into three age groups: Late Paleoproterozoic (e.g., Chiney complex, Malozadoisky massif), Late Mesoproterozoic (e.g., Srednecheremshansky massif), and Neoproterozoic (e.g., Kingash complex, Yoko-Dovyren massif, and massifs in the center of the East Sayan Mts.). In most massifs but Chiney the initial magmas are magnesium-rich. On paleogeodynamic reconstructions, the position of the studied massifs is the evidence that three most precisely dated events in North Canada continued into southern Siberia: In the period 1880-1865 Ma, it was the Ghost-Mara River-Morel LIP; at 1270-1260 Ma, the Mackenzie LIP; and at 725-720 Ma, the Franklin LIP. In Siberia, the mostly productive massifs with respect to PGE-Ni-Cu mineralization are those linked with the Franklin LIP: Verkhnii Kingash, Yoko-Dovyren, and central part of the Eastern Sayan Mountains, e.g., Tartay, Zhelos, and Tokty-Oy.
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