Sulfides and Intermetallics in Mantle Peridotites from the Kamchatsky Mys (Eastern Kamchatka)

Mantle peridotites, rocks from the lower part of the ophiolite complex, were studied on the Kamchatsky Mys Peninsula (eastern Kamchatka). Cu and Ni sulfides, native copper, awaruite, and microinclusions of (Cu?)Pd5In2 were described in fresh (non-serpentinized) harzburgites. The structure and composition of the studied rocks support a primary (mantle) origin for the sulfides. Native phases formed by the reduction of metals from sulfides during the percolation of free hydrogen through the rocks. Hydrogen was released during serpentinization of mantle peridotites in the underlying slabs. The presence of a sulfide phase in the Kamchatsky Mys mantle peridotites may be related to their origin in a mantle plume-influenced environment.