THE DEEP STRUCTURE OF THE EARTH'S CRUST DURING THE TRANSITION FROM THE STRUCTURES OF NORTHERN SIKHOTE-ALIN TO THE ISLAND OF HOKKAIDO (JAPAN)
Z.N. Proshkina, M.G. Valitov, N.S. Lee
V.I. Il'ichev Pacific Oceanological Institute, Far Eastern Branch Russian Academy of Sciences, Vladivostok, Russia
Keywords: structural and density modeling, deep structure, gravity field, Tatarsky trog, north-western part of Hokkaido
Abstract
The paper presents the results of structural and density modeling using the 26-MP8 profile, which stretches in a meridional direction and intersects the structures of the northern Sikhote-Alin, coastal complexes of the East Sikhote-Alin volcano-plutonic belt, the South Tatar Basin, and the northwestern part of the Japan-Sakhalin Borderland with access to the island of Hokkaido. Modeling revealed inhomogeneities in the basement, as well as a complex rearrangement of the earth's crust on the traverse of the La Perouse Strait, where strong fragmentation in the middle crust and a deep fault were revealed, probably forming the boundary between the structures of the South Tatar basin and the northwestern part of the borderland. The foundation of the borderland is complicated by numerous faults and increased densities in individual blocks that coincide with or are associated with volcanic centers. A section of crustal contraction has been identified in the area of the northeastern closure of the Central Basin of the Sea of Japan and the thinning of the continental crust north of Cape Surkum.
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