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 35000km

2

.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.