On the Problem of Distinction between Recent Geodynamics of Central and East Asia

Abstract

Abstract—The Central Asian and East Asian transitional zones are distinguished in Central and East Asia south of the Late Precambrian–Paleozoic fold belts of the Southern Russia and Kazakhstan and east of the Siberian Platform which are parts of the North Eurasian lithospheric plate. These transitional zones separate the plate from the Indian, Australian, and Pacific plates. The Central Asian zone is presently dominated by tectonic transpression accompanied by the thrusts and strike-slip deformations extensively developed under the influence of the Hindustan indenter pressure. The East Asian zone is mainly controlled by transtension with extensive shear strain processes associated with the deep submergence and, apparently, gradual disintegration and disappearance of the Pacific slab at a depth. This regime can also be connected with the ascending mantle plumes beneath Transbaikalia and North Mongolia. The Cenozoic rift structures and large depressions prevail in the East Asian transition zone. The difference in the geodynamic regimes in the transitional zones is demonstrated by seismic data and by the analysis of geophysical fields and anomalies in their deep structure. The boundary between the zones approximately coincides with the extended submeridional 102°–104° E geodivider which is identified based on numerous geological and tectonic manifestations in the North, Central, and South Asia. In the central part, the geodivider is supported by the data on recent crustal block structure, seismicity, active faults, and deep structure anomalies.