ESTIMATION OF THE GRAVITY FIELD AND VALUE IN ZHUMULANGMA PEAK AND ITS VICINITY
Zhang Chijun and Zhan Jingang (Institute of Geodesy and Geophysics, CAS. Wuhan 430077)
Based on the limited gravity observations, the gravity features in Zhumulangma peak and its vicinity are analyzed. The result shows that the space anomalies which are controlled by topography are positive and changeable intensively over the Zhumulangma. The Bouguer gravity anomalies, however, are negative and greater than that of the northern plateau in Zhumulangma, which indicate the mountain root under the Himalayan is not the deepest, though the Himalayan is the highest peak in the world. The isostatic gravity anomalies in Zhumulangma are positive and greater than that in the northern and southern side, which explore that there could be the high density materials beneath the Himalayan ridge. In addition, according to the intense correlation of the Bouguer with height and four kinds of formulas, the gravity value at the top of Zhumulangma peak is estimated to be 976980×10 -5 m·s 2 with mean error 6.5×10 5 m·s 2 . The result can provide the necessary data for determining precisely the geoid and orthometric height of Zhumlangma peak.