Abstract:

The Fen-Wei graben system is located between the Yinshan and Qinling tectonic belts in Eastern China, and comprises (from north to south) over 10 Cenozoic downfaulted basins in the NE syncline, such as the Jining, Huailai, Datong, Yuxian, Xinzhou, Taiyuan, Jinzhong, Fen-Wei, Tianshui, Lixian, Xihe, and Chengxian. This shows that the North China block rotated clockwise in the Cenozoic and caused its rifting, which can be called “S”-type rotation and pull-apart tectonic system. This system had a broad and far-reaching influence on the tectonic framework and development of Eastern China, and strongly modified the tectonic framework of the Qinling-Dabieshan belts and the northern margin of the Jiangnan massif. This may have resulted in the segmentation of the Neo-Cathaysian tectonic system, and initiated the extensional tectonics of the North China Block that reached as far as the Ryukyu trench. Similarly, the Baikal graben system in Russia and Mongolia is composed of Cenozoic rift basins with an inverted-“S”-shaped pattern, and was also developed in ancient crystalline blocks. This represents anti-clockwise rotation of the reversed “S”-type rotation pull-apart tectonic system. Our study shows that they belong to the same tectonic type, and a way of ancient continental block rifting.

Key words: Fen-Wei graben system, Fen-Wei “S”-type rotation pull-apart tectonics, Neo-Cathaysian high-rank associated fault zone, Neo-Cathaysian tectonic segmentation, Baikal reversed S-type rotation pull-apart tectonics, ancient block rifting