Mantle plumes and other structures of Siberian and East-European Platforms related to localization of giant mineral deposits

Abstract

The structure of subcontinental mantle convection was discovered using direct and indirect indicators of mantle convection cell (MCC) boundaries (Kravchenko & Khain, 1990, 1996, 1997). The boundaries serve as hotlines, i.e., zones of ascent of hot mantle matter and plumes trained by triple junctions of MCC. This discovery let us predict the localization of Noril'sk type (Cu-Ni-Pt) ore deposits at the South-West of the Baikal rift, in the middle current of the Lena river and at North (Polar) and South of the Ural, and the localization of Tomtor type (REE-Nb-P) ore deposits in the intersections of Moho ridges (up to 15 km high) in the Northern Siberian Platform (Kravchenko et al., 1997; Khain & Kravchenko, 1999).The prediction related to the Polar Ural seems to be confirmed (there occurs the Pt-bearing dunite-clinopyroxenite massif Seum-Keu with diameter 120 km). The structure of the East-European Platform is of another type, which determines other, more complicated conditions of ore deposit localizations. The East-European Platform has a round, peripheral uplifted zone. Along this zone all known ore deposits, including giant ore deposits (Pechenga, Khibina, Lovozero, and others) are localized. The Ural geosyncline, related to one of four global lineament zones, is situated firmly to the east boundaries of the Platform. But laws of ore deposits localizations are the same for both the Siberian and East-European Platforms. They are the localization of ore deposits in the meridional rift zones, developed since early Riphean and repeatedly reactivated, and their disposition in intersections of transform faults or other rifts.