The Chuxiong Mesozoic Basins In The Original Basin To Restore Its Evolution, And

Chuxiong Basin is a typical reformed basin, which formed during Mesozoic-Cenozoic periods in south of China and has good petroleum geological condition. As to the development and evolution of the basin, on the basis of widely summing up preceding research, applying the thinking of "whole, dynamic and integration ", this study mainly reconstructs the sedimentary boundary of the basin during every stage of Mesozoic and reverts to the original basin, then illuminates the property of Chuxiong Basin and characteristics of its evolution.As to the property of the basin, different people have different viewpoints. This study shows a detailed conception and characteristics of foreland basin, and indicates that the time limit of Ailao Mountain is the key to identify the property of Chuxiong Basin. By analyzing Ailao Mountain and the movement of Red River Fault belt, this study indicates that Ailao Mountain does not exist during the middle-late Triassic and Jurassic period. Even if existence, it is only a chaining-island. And it does not uplift as a big mountain until the early Cretaceous. Therefore, there is not a tectonic condition for Chuxiong Basin to be a foreland basin at that time. The strike-slip movements of Red River Fault Belt control the present geographical pattern of Chuxiong.On the basis of identification of uplifting time of Ailao Mountain, by analyzing the sedimentary characteristics of Chuxiong Basin and Simao Basin lying in the west of Chuxiong Basin and considering the two basins as a whole, paleolithofacies map shows that the two basins are correlative, consistent and compensatory. If regarding the two basins as a whole, the distribution of sedimentary facies and environment becomes more continuously and integrally and the outline of the whole basin becomes more clearly. So the two basins are a big whole basin during the Mesozoic period. The two basins accept deposits as a whole and do not take apart into two unattached basin until the Ailao Mountain has uplifted on a large scale during the early Cretaceous period. From then on, the two basins develop respectively.By analyzing of the structural stress field, lava, clastic rock, mineral and geochemistry, this study contrasts the structural setting of the two basins. It can be conclude that the Chuxiong Basin situated in a stretching background. The development and evolution of the basin has a near relationship with the basins around, especially the Simao Basin. Both of the basins have the character of continental rift basin. It provides more proofs to stand up that Chuxiong Basin is a splitted - depression basin formed in a tensive surroundings. Integrating the structural and sedimentary characteristics of Chuxiong Basin, three main phases of basin evolution can be identified: subsiding - splitting of the basement, differential sediment and depression and strike-slip extrusion stage.