Geodynamic Scenario and Structural Styles of Mesozoic and Cenozoic Basins in China

Abstract

The continental lithosphere of China is situated at the junction of the Marginal-Pacific and Tethys-Himalayan tectonic domains. The most manifest tectonic movements responsible for the deformation of the continental lithosphere of China are taphrogenic, collisional, and shearing. These movements played an important role in the Mesozoic and Cenozoic tectonic evolution of China and formed various types of Mesozoic and Cenozoic basins in China. The Marginal-Pacific crust in eastern China was attenuated by rifting and developed north-northeast-trending Mesozoic and Cenozoic basins, e.g., the Songliao, Bohai Bay, and Jianghan basins. Rifting mainly followed preexisting lineaments or shear zones in the basement. Then basin-range (graben-horst) structures and large fault-bounded basins developed. Extensional structural styles have prevailed in Mesozoic and Cenozoic basins in eastern China, with listric faults and tilted blocks in the basement, and detached faults, growth faults, and rollover anticlines or drape folds in the cover rocks. These structures are favorable for hydrocarbon accumulation; thus, the famous Daqing and Zhongyuan oil fields formed in Songliao basin and Bohai Bay basin, respectively. In western China the continental crust thickened by collision and formed a series of Mesozoic and Cenozoic intermontane and foreland basins, such as the Junggar (Dzungaria), Tarim, and Qaidam basins. Contraction structural styles are predominant in Mesozoic and Cenozoic basins in western China, with shortened fault blocks and ramps in basement, and thrust faults and folds in the cover rocks. The Kelamayi and Laojunmiao oil fields formed in these compressional basins. In addition, many great wrench faults played an important role in the evolution of China, such as the Tan-Lu fault in eastern China and the Altunshan and Talaso-Fergana faults in western China. Many Mesozoic and Cenozoic basins of China were characterized by transtension and transpression. The Mesozoic and Cenozoic basins of China have undergone numerous tectonic events. The extensional structures have been changed into contractional structures, or conversely. Thus, tectonic inversion occurred in successive events, and different structural styles may be found in different tectonic levels of these basins. These superposed deformations and structures have complicated petroleum exploration, but they also enlarge prospective exploration targets and potential hydrocarbon reserves in China.