ONCE MORE CONCERNING THE ORIGIN OF THE KURILE BASIN OF THE SEA OF OKHOTSK

Abstract

The paper discusses data that support the view that the Sea of Okhotsk region is a dynamic geosynclinal region. However, at least in the southern part of the region, the geosynclinal process involved only the emplacement of the granite and metamorphic crust by an autochthonous mechanism without significant manifestations of crustal destruction. The onset of the geosynclinal process was apparently largely associated with magmatism that was accompanied by uplift of local structures and faulting. In the Late Cenozoic, large-throw tectonic movements in zones that now constitute the margins of the deep basin of the Sea of Okhotsk, became dominant. The regions of mature, older continental crust (Sakhalin and Hokkaido) which by that time had undergone complex geological development, were definitively exposed above the sea level. In the central part of the present Sea of Okhotsk there developed the submarine rises of the Academy of Sciences and the Institute of Oceanology, both of which are examples of stages of incomplete development of continental crust. This development proceeded to an even smaller degree of completion in the deep basin of the sea.