Structural Characteristics And The Relation With The Petroleum And Gas In Chagan Depression Of Yin-E Basin Of Inner Mongolia

Chagan sag is a secondary tectonic unit in Chagandelesu Depression, northeastern Yingen-Eji'naqi basin, and the basement of the basin is a Paleozoic fold belt of continental margin or island arc at the connection region of North China plate* Tarim plate and Kazakstan plate, with the character of erogenic belt.In working area and its adjacent area, the forming tectonic setting of Indosinian intrusion was that orogenic belt pressed strongly, intracontinental subduction; that of early Yanshan movement epoch was the stress field transferred from compression to extension meanwhile the incrassate crust of orogenic zone turned to extensional collapse; and that of early Cretaceous volcanics was that the area structure extensional collapse further more during the post period of orogenic phase. The main structure style of Chagan sag included four kinds, such as extension, compression, inversion and strike-slip structure, in which the extension structure was the principle part. The hanging wall of sag extended in southeast direction, with the Tulage fault being the boundary fault. Yinggete-Bagemaode metamorphic core complex developed adjacent to northwest of Chagan sag, which evolved from late Jurassic to Cretaceous with three-layer construction style. The kinematics mechanism of metamorphic core complex and Chagan sag is a simple shear model, Chagan sag extended and faulted as the metamorphic core complex rised. The structure evolution and the earth dynamics mechanism of Chagan sag and its adjacent area during Miocene-Cenozoic. Divided four favorable places for prospecting based on the discussion of relation between the structure character and petroleum and gas of Chagan sag.