GRAVITY ANOMALIES AND CRUSTAL STRUCTURES IN THE QINGHAI-XIZANG PLATEAU
Meng Lingshun Gao Rui Zhou Fuxiang Li Li Wang Huaxiao(Changchun University of Earth Science, CAGS)
As a important part of the research plan of Chinese committee on Li-thosphere, the Changchun College of Geology togeth er with Lithosphere Center of Geological Academy in Chian carried out the gravity measurements of repairing stations (1:500000) along Golmud, Qinghai-Yadong,Xi-ang area in 1987. 201 stations were laid out along the profile which was about 1619 km in length. Based on these measurement datas, Mono depth and isostatic anomalies according to Pratt hypothesis were computed in this research area. The isostatic information of earth' s crust and upper mantle were analysed. Using correlation analysis of the Bouguer anomaly and station elevation, nine terranes and thirteen larger faults were divided in the tracsect. Finally,according to gravity standpoint the model of plateau uplift and collision of the plates was carried out. The direct force of plateau uplift is collision of the plates. The isostatic rise of plateau caused by glacier melting is verv slender and unimportant; distinguising of it from rapid rise caused by structure movement is very difficult.