THE JUNCTION OF THE EASTERN CENTRAL ASIAN FOLD BELT AND THE SIBERIAN PLATFORM: DEEP STRUCTURE AND MESOZOIC TECTONICS AND GEODYNAMICS
B.F. Shevchenkoa, M.V. Goroshkoa, A.N. Didenkoa,b, V.A. Gur'yanova, V.S. Starosel'tsevc, and A.S. Sal'nikovc
aYu.A. Kosygin Institute of Tectonics and Geophysics, Far Eastern Branch of the Russian Academy of Sciences, ul. Kim Yu Chena 65, Khabarovsk, 680063, Russia
bGeological Institute, Russian Academy of Sciences, Pyzhevskii per. 7, Moscow, 109017, Russia
cSiberian Research Institute of Geology, Geophysics, and Mineral Resources, Krasnyi pr. 67, Novosibirsk, 630091, Russia
Keywords: Deep structure, tectonics, geodynamics, folding and thrusting, reference depth profiles, Central Asian Fold Belt, Siberian Platform
Pages: 1672-1679
Abstract
The tectonic structure of the junction of the eastern Central Asian Fold Belt and the Siberian Platform, along with the deep structure of the Earth's crust and lithosphere in this region, has been described on the basis of new-generation geological and geophysical data (seismic, geoelectric, and space-structural studies as well as new-generation geological maps), combined with new interpretation techniques (processing of the previous data by special software). The data suggest the existence of oblique collision during the convergence of the tectonic plates and, correspondingly, tectonic units composing these plates, when the Mongol-Okhotsk paleobasin closed. Such a scenario within the Aldan-Stanovoi Shield is evidenced by areas of syn- and postcollisional magmatism, with their deep-level and geochemical characteristics, and by the presence of a Late Mesozoic fold-thrust zone. Deep "traces" of these tectonomagmatic events, detected in the course of geological and geophysical modeling, are manifested as inclined deep boundaries between the crustal and lithospheric blocks. On the Earth's surface they correspond to large fault systems: Dzheltulak, North and South Tukuringra, Gilyui, and Stanovoi. It has been found that the influence of collision decreases northward with distance from the junction of the eastern Central Asian Fold Belt and the Siberian Platform (Dzheltulak and North Tukuringra transcrustal faults).
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