Geophysical characteristics and prospecting significance of deep structures in Dongpo ophiolite body, Tibet

Abstract:Geophysical survey of Dongpo rock mass on the south bank of Yarlung Zangbo River in western Tibet was carried out using multiple methods, and the inversion of aeromagnetic survey anomaly precisely positioned by ground magnetic survey revealed the range of the deep magnetic body in Dongpo rock mass; seismic reflection survey delineated the weak reflection places under the rock mass with reflected wave characteristics different from those of outcropping ophiolite body; meanwhile,as confirmed by MT method, the low-resistivity bodies under the rock mass are at the roughly identical places. The outcropping ophiolite body extends downward, resembling a pot bottom as a whole, and its middle part is characterized by low resistivity and weak reflected wave. In addition, magnetic minerals are relatively developed at the depths of 1.5km-3.0 km, which might be the very section of chromium-bearing rock mass having strong mineralization and alteration; the similar characteristics were observed in the Luobusha mining area, and hence these places are favorable for ore prospecting.