ABSTRACT
According to regional structural and tectonic reconstructions, numerous maficultramafic massifs belonging to ophiolite associations are concentrated in Paleozoic, Mesozoic, and younger folded structures along the northwestern shore of the Pacific, from Chukchi Peninsula to the islands of Japan; they are of various structures and compositions. Certainly, a comprehensive study of these massifs is interesting for solving general problems related to the geodynamic evolution of the crust and upper mantle and the formation of ophiolite associations in this large segment of the Earth; also, it is interesting for assessment of the ore potential of these igneous complexes. Published data show that mafic-ultramafic massifs of Sakhalin Island mark the wide zone of the long-lived deep-seated fault traced along the Sea of Okhotsk shore of the island, from northern peninsulas to Aniva Bay.
