Episodic Rifting Dynamic Process and Quantitative Model of Mesozoic-Cenozoic Faulted Basins in Eastern China

Integrated analysis of basin filling and tectonic evolution, aimed with computer modeling technique, reveals the (dynamic) process of basin subsidence, sedimentary infill, structure and thermal evolution in response to the multiple rifting processes of the Mesozoic-Cenozoic rift basins in eastern China. The synrift phases of these basins, such as the Bohaiwan and Jianghan basins, usually include 3 to 4 rifting episodes, and the trends of syndepositional faults, the type of volcanic rocks and the distribution of depocenters and depositional systems changed significantly in different rifting stages. The episodic change in tectonic subsidence rate controls the development and evolution of the regional (the second order) sequences. In intensively rifting subsidence episodes, deep lacustrine basin sequences are usually observed, while during the initial and final rifting episodes shallow lacustrine and fluvial basin sequences commonly form. The process of episodic rifting significantly differs from that of the simple rifting in tectonic subsidence and deep heat flow, and can not be accurately described by a simple (one episode) stretching model. Through correction of the initial stretching condition of each rifting episode and stretching index , we have programmed a multiple uniform instantaneous stretching model to simulate the formation of the basins. This model has been applied to reconstruct the lithosphere structure and to evaluate the deep thermal evolution of the Yinggehai basin. The calculated results are in agreement with geophysical data and geological observation in the basin.