Geochemical and tectono-magmatic evolution of the volcano-sedimentary rocks of Pechenga and other greenstone fragments within the Kola Greenstone Belt, Russia

During the final phases of the Kalevian rifting event, tholeiitic and ferropicritic magmas were generated from two distinct mantle sources. The tholeiitic magma was derived from a subabyssal, depleted mantle source. In contrast, the ferropicritic magma came from an abyssal, metasomatically enriched mantle source. The larger degree of mantle contamination in the latter was probably critical in the formation of the Ni-Cu ores of the Pechenga gabbro-wehrlite intrusions.