RUSSIAN JOURNAL OF EARTH SCIENCES VOL. 7, ES5002, doi:10.2205/2005ES000190, 2005
[121] The evolution of the continental margin had a cyclic character and was interrupted by the epochs of global and regional structural rearrangements, recorded at five age levels: (1) the period from the end of the Neocomian to the beginning of the Aptian was marked by the displacement of the continent-ocean boundary from the eastern Sikhote Alin area, and by the formation at the oceanic basement of the accretion-type structural features of the Hokkaido-Sakhalin fold system, which developed under the conditions of the oblique, left-lateral subduction; (2) the boundary between the Early and Late Cretaceous was marked by the crowding of the continental margin, island arc, and oceanic terrains in the Hokkaido-South Sakhalin-Tatar Strait area as a result of the large-scale strike-slip movements along the continental margin; (3) the formation during the Early Campanian of the system of ensimatic island arcs, separated from the continent by epioceanic marginal seas; (4) the formation during the Paleocene of a collision-type structural feature in the eastern areas of Central Sakhalin and the origin, at its southern flank, of the sublatitudinal structural features of the Okhotsk active continental margin, which in South Sakhalin, were connected, in mullion manner, with the Cretaceous structural features of the East Asian margin; (5) the Middle Eocene witnessed the collision of the Tokoro ensimatic arc with the proto-Japan continental margin, the formation of the Aniva composite terrain, and the migration of the convergent boundary over a large distance farther east and southeast. Each of these epochs concluded the respective period of the growth of the continental margin and caused a change in the mechanism of its accretion.
[122] The characteristic feature of the Cretaceous-Paleogene evolution of the East-Asian continental margin was the predominant growth of its Sea of Okhotsk segment in the southern direction (from the Okhotsk-Chukotka volcanic belt to South Sakhalin and to the Academy of Science High) by more than 1000 km. At the same time, the Sea of Japan sector of the continental margin grew in the eastern direction (from the Jurassic-Early Cretaceous accretion-type structural features of the Sikhote Alin Range to the accretion-type structural features of East Sakhalin and Hokkaido) by merely a few hundred kilometers, taking into account the closed Sea of Japan. These specific features can be explained by the different mechanisms of the accretion, namely, by the alternation of the processes of the primarily orthogonal subduction and collision of the intraoceanic terrains in the Sea of Okhotsk sector, and by the left-lateral oblique subduction and the transform-type movements of the polygeodynamic terrains along the continental margin.
Citation: 2005), South Sakhalin tectonics and geodynamics: A model for the Cretaceous-Paleogene accretion of the East Asian continental margin, Russ. J. Earth Sci., 7, ES5002, doi:10.2205/2005ES000190.
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