Hydrothermal polymetallic mineralization of the transition zone Land-Sea, Pechenga ore district, Russia

The main mineral deposits of the Pechenga ore district were formed during t he Karelian cycle. The hydrothermal lead-zinc mineralization at the Pecheng a seacoast and the copper-zinc mineralization in the Kola superdeep borehol e section are superimposed on the Karelian structures and originated in a d ifferent environment. This environment has not been previously clarified. T he paper is based on the detailed studies of lead-zinc and copper-zinc mine ralization and regional investigations of the northwestern Baltic Shield an d the adjacent territory of the Barents Sea. These combined data are used t o characterize the transitional zone Land-Sea in the Pechenga ore district and to suggest that the polymetallic ore mineralization is associated in sp ace and time with Riphean structures of this zone. The polymetallic mineral ization was formed during the Baikalian stage of the Barents Sea shelf plat e development when the Pechenga ore district was situated within a passive continental margin. In favor of this suggestion data from the integrated ge odynamic model of the Pechenga ore district, sea geotraverse AR-1, internal structure of the Voron'ya-Kolmozersk fault system, structural control of l ead-zinc veins at the Pechenga coast, and Kola superdeep borehole studies a re presented.