Platinum placer dposits of the Seinav-Galmoenan Ore Complex, Koryak Foldbelt, Far East Russia: Mineralogy and tectonic aspects of the origin

摘要

The Koryak-Kamchatka platinum-group elements (PGE) deposits are represented by Quaternary valley and bench alluvial placers in the vicinity of the Galmoenan and Seinav Late Cretaceous -Paleo-cene gabbro-clinopyroxenite-dunite massifs. The heavy mineral placer fraction is characterized by a domi-nantly Ir-Pt assemblage. The PGE minerals are dominated by isoferroplatinum including 25 mineral species. The melange zone development with an intensive tectonic crushing and serpentinization of a significant volume of the dunite material is the reason that the Koryak-Kamchatka PGE placers have been formed for a relatively short period of geological time.