LOW-VELOCITY LAYERS AND PARTIAL MELTING IN QINGHAI-TIBET PLATEAU
LI Hai-ou1, JINAG Mei2, WANG You-xue1,3, ZHANG Yu-wen1
1. Institute of Geophysics and Information Technology, China University of Geosciences, Beijing 100083, China;
2. Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;
3. Department of Resources and Environmental Engineering, Guilin Institute of Technology, Guilin 540014, China
There exist evident differences in crustal structure and thickness among various terranes in Qinghai-Tibet Plateau. The crustal structure histograms of these terranes are presented. Studies show that it is the tectonic superposition of the crust caused by the collision of terranes that results in the development of the low-velocity layers in the crust of most terranes. The shallower crustal layer with felsic-intermediate composition is considered to be the lower half of the crust, with the original composition preserved. The materials of the low-velocity layers have not been subjected to partial melting because the temperature remains lower than the melting solidus.
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