NEW ELEMENTS OF THE TECTONICS OF THE CHUKCHI SEA

Abstract

New seismic data obtained by the 'Soyuzmorgeo' All-Union Producing Combine (VMNPO) on the structure of the sedimentary cover and the basement of the Chukchi (Chukotka) Sea have permitted a new approach, differing from existing concepts to ascertaining the tectonic nature of this marine basin. The main feature of the structure of the sedimentary cover along this section is the steady general southeastward descent of the complexes forming it, toward the coast of Chukotka (toward Kolyuchiy Bay), with an increase in recorded thickness to 4.5 km, accompanied by a narrowing of the stratigraphic range by the pinching out of the lower complexes of the section. The maximal thicknesses of the lower part of the section occur near the Wrangel Island uplift, whereas the thicknesses of the upper part of the section are greatest off the coast of Chukotka. This indicates a substantial reorganization of the tectonics and a change in inclination of the accumulation surfaces along the line of Profile I during the formation of seismic Complexes C and B - that is, according to the stratigraphic subdivision adopted, in the Late Cretaceous-Paleogene interval, which on the whole is consistent with the phase of considerable reorganization of the structure on the land adjoining the region under study.