THE FORMATION AND EVOLUTION OF THE BAOSHAN BASIN, YUNNAN PROVINCE

The Baoshan basin is a typical Tertiary basin in west Yunnan Province,which is composed of western fault zone,central sag zone and eastern slope zone.The extenslonal quantity is from small,to big and to small from the north to the south of the basin.The extensional history consists of three cycles.Three un conformities can be recognized in the basin.The process of the formation and evolution of the basin can be divided into the primary formation stage,the extensional development stage and the filling stage.