Low-sulfide PGE and nickel sulfide metallogeny of Paleoproterozoic riftogenesis of the Fennoscandian Shield

Аннотация

By the end of the Archean, the period of active volcanism, plutonism, accretion, and cratonization had been completed by the construction of stable continental plates. Afterward, cratons were subject to intense extension owing to mainly mantle diapirism and ascent of asthenospheric flows, which gave rise to the formation of ensialic intracratonic basins, whereas other linear troughs were expressed in the formation of continental rifts. Zones of continental rifting are characterized by a wide spectrum of mineral resources (Cu, Ni, PGE, Co, Ti, V, etc.) related to igneous complexes. This paper is focused on metallogeny of nickel-sulfide and PGE mineralization in the Fennoscandian Shield. The results of metallogenic analysis of Paleoproterozoic riftogenesis, along with the account of previous achievements, have shown that the aforementioned mineralization is related to three consecutive plume-tectonic pulses of mantle activization, which are expressed in (i) upwelling of the subcontinental mantle enriched in LREE, (ii) intrusion of mafic and ultramafic melts derived from enriched and depleted Archean mantle sources, and (iii) formation of low-sulfide Pt–Pd and Pt-bearing Cu–Ni sulfide deposits.