Ultramafic-mafic igneous complexes of the Precambrian East Siberian metallogenic province (southern framing of the Siberian craton): age, composition, origin, and ore potential

Based on new data on the age, mineralogy, and geochemistry of ultramafic-mafic complexes in the Precambrian structures of the southern periphery of the Siberian Platform, the East Siberian metallogenic (PGE-Cu-Ni) province is recognized. It includes the Yenisei Ridge, Precambrian Kan uplift, Alkhadyr terrane with the adjacent structures of the Biryusa block, and northern Baikal region (Yoko-Dovyren and other massifs of the Baikal-Patom basin). We have established that the U-Pb and Ar-Ar ages of ore-bearing complexes of dunite-peridotite-pyroxenite-gabbro association correspond to the Late Riphean (728-710 Ma). The mineralogical and geochemical similarity of ore-bearing complexes in different areas testifies to their genetic entity. All parental melts were similar in composition to picrites. The calculation results and the PGE enrichment of rocks and ores show high degrees of melting of the mantle source, which agrees with the plume model of formation of the ore-magmatic system. The recognized province is similar in the type of magmatism and time of its occurrence to the Franklin LIP in northern Canada. It is one of the highly promising ore districts of East Siberia. (C) 2013, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved.