Paleomagnetic study on deformation of the eastern part of the Asian continent

The eastern part of The Asian continent formed by sequential welding of five micro continentsduring Paleozoic and Mesozoic eras （Siberian craton, Mongolia block, North China block）South China Block (SCB) and India . We focus deformation of the eastern part of Asia associated with这些collision events.我们提供pose deformation modes in continental southeast Asia on basis ofpaleomagnetic studies of Triassic to Eocene strata for the Mongolia block，SCB and Southeast Asia1.Counter-clockwise rotation is observed in the eastern part of the MongoliaThis rotation is ascribed to post-Late Cretaceous extension that affected the continentalbasins (the Middle Amur, Sanjiang, Razdolnian，Amur-Zeyn and Songliao basins) of the northeast Chinese Plain along the eastern margin of theMongolia Block.2.Regional deformation aspects of the SCB are inferred from Middle Triassicpaleomagnetic data. An area located between 70公里and 225公里from northern margin of the SCB forms a稳定平台where very little relative rotation has been detected later than the Middletriassic . however,inner region of this block experienced a clockwise rotation of 12°to 30°with respect to stableouter region. Areas in close vicinity of the Tan-Lu fault were subjected to post-Triassic90 - counter-clockwise rotation with respect to stable tectonic belt.3.我们已回顾three phenomena are important factors for explaining the prominent deformation aspect of Southeastasia;that is, fragmentation，coherent rotation and internal deformation associated with displacement. When印度collided toAsia, at first，fragmentation occurred. The Chuan Dian fragment and The Shan-Thai block were separated from Thecontinuum Asian continent. Secondly，这些连续的fragments experienced a coherent tectonic rotation. At the later stage of thecollision五,连续fragments experienced internal deformation associated with the southward displacement。

The eastern part of the Asian continent was formed by sequential welding of five micro continents during Paleozoic and Mesozoic eras (Siberian craton, Mongolia block, North China Block, South China Block (SCB) and India). We focus deformation of the eastern part of Asia associated with these collision events. We propose deformation modes in continental southeast Asia on the basis of paleomagnetic studies of Triassic to Eocene strata for the Mongolia block, SCB and Southeast Asia1.Counter-clockwise rotation is observed in the eastern part of the Mongolia block. This rotation is ascribed to post-Late Cretaceous extension that affected the continental basins (the Middle Amur, Sanjiang, Razdolnian, Amur-Zeyn and Songliao basins) of the northeast Chinese Plain along the eastern margin of the Mongolia Block.2.Regional deformation aspects of the SCB are inferred from Middle Triassic paleomagnetic data. An area located between 70 km and 225 km from northern margin of the SCB forms a stable platform where very little relative rotation has been detected later than the Middle Triassic. However, the inner region of this block experienced a clockwise rotation of 12° to 30° with respect to stable outer region. Areas in close vicinity of the Tan-Lu fault were subjected to post-Triassic counter-clockwise rotation by 90゜ with respect to stable tectonic belt.3.We have recognized that three phenomena are important factors for explaining the prominent deformation aspect of Southeast Asia ; that is, fragmentation, coherent rotation and internal deformation associated with displacement. When India collided to Asia, at first, fragmentation occurred. The Chuan Dian fragment and the Shan-Thai block were separated from the continuum Asian continent. Secondly, these continental fragments experienced a coherent tectonic rotation. At the later stage of the collision event, continental fragments experienced internal deformation associated with the southward displacement.