Abstract:

The Chuxiong Basin in central Yunnan is a unsymmetrical half-basin of the Mesozoic,The basin is deeper in the west and shallower in the east and ran-ges about 35000km².According to maps of the basal texture and the crust thick-ness,the basin can be divided into two units of the eastern uprising and wes-tern depression.From north to south,the former consist of the Yongren Uplift,Chuxiong Depression and Dahongshan Uplift,the later contains of Huaping Up-lift,Yanfeng Depression and Yunnanyi Uplift,All these uplifts and depres-sions are separated by fractures.Some of the secondary gravity anomalies arefound to be in coincidence with anticline structures.It is proved by study that free-air anomaly is corresponding to the thick-ness of deposition.According to the positive anomaly,the author suggest that the Yanfeng,Mouding,Shuangbai and Yao'an-west Nanhua stuctures within the basin are the deposit centers.Calculation results show that the eastern part of the basin is the uplift of the mantle,and the western part is its slope.