青藏高原及周边地区下地壳地球物理异常及成因

青藏高原及周边地区下地壳普遍发育电性高导层、波速低速层和热流密度值异常区.下地壳电性结构和速度结构明显具有纵向分层和横向分块的特点,其热流密度值具有明显的南北条带性和东西分块性.下地壳高导层、低速层和热流密度值异常区与青藏高原及周边地区各构造单元有一定的匹配性,异常区的形成与青藏高原和周边盆地耦合过程中下地壳岩石的热软化以及韧性流动有关.下地壳层流是下地壳岩石热软化和韧性流动的结果,青藏高原的隆升是层流作用的表现,目前层流作用的动力来源于恒河盆地下地壳,层流方向由恒河盆地流入青藏高原.

Geophysical Anomaly of Lower Crust of Qinhai-Tibet Plateau and Its Adjacent Regions

The analysis of the spatial distribution characters and attitudes of high-conductance layer, lowvelocity layer and heat flow value anomaly respectively and their corresponding relationship proves that the electricity and velocity fabrics of lower crust in Qinghai-Tibet plateau are characterized by the vertical layering and horizontal dispersing. It is also found that the telluric heat flow value is stripped from south to the north and dispersed from east to the west. Different structural belts and the one experiencing different structural evolution own obvious discrepancies in electricity fabric, velocity fabric and heat flow value. It is concluded that the uplift of Qinghai-Tibet plateau is related to the softening and ductile flow of the lower crust rocks beneath the basins around the area.