Prototype and Sedimentation of Red Basins along the Ganhang Tectonic Belt
YU Xin-qi 1SHU Liang-shu 1YAN Tie-zeng 2ZU Fu-ping 1 1 (Department of Earth Sciences of Nanjing University, Nanjing210093 ) 2(Zhejiang Geological Survey, Xiaoshan, Zhejiang 311203)
Basin-prototype belongs to the tectonic property when sedimentation occurs. The method of prototype analysis is just used to distinguish one stage basin types from the other stages. Other than working on the volcanical-fault basins of the first circle produced in the late Jurassic-early period of early Cretaceous, this paper discussed on the prototype and sedimentation of red fault basins along the Ganhang Tectonic Belt of the second circle, they produced after late period of early Cretaceous. There is a series of red fault basins at the center of the Ganhang Tectonic Belt, such as the Fuzhou-Chongren Basin, Xinjiang Basin, Jinhua-Quzhou Basin and Zhuji Basin, distributing northeastward and mostly contacting each other in there two ends. Combiningwith the regional extension background manifested by the basalts at the bottom of red beds, these basins started at the late period of early Cretaceous, and almost every basin displayed an one-tendency fault basin in geometry, which are all restricted within the normal fault in the north and unconformable boundary in the south. By the middle-late period of late Cretaceous, all basins turned into depressive basins, thus the sediments overlay on the basement of the two sides, and there are some self-generating dolomite, marlite and claystone deposit in the centre. In the evolutional process of the red fault basin, the fluvial sedimentation plays a much important role than any other ways of deposition. The sedimentary facies vary from lake facies to fan facies, delta facies and fluvial facies, etc. This assembly is the basic sedimentation type of an extensional fault basin, and the changing model reflects the evolutional process of the fault basin from initial extension (deep lake) to final wither (ground river).