喜马拉雅碰撞带陆壳增厚和隆升机制——一种陆壳构造演化模式

“回流”是大陆碰撞带内普遍发生的一种构造-物理过程。本文基于喜马拉雅碰撞带的地质、地球物理事实,提出“回流”模式,以阐明喜马拉雅碰撞带各种地质、地球物理过程的内在联系,揭示大陆碰撞带的构造演化规律。

MECHANISM FOR CONTINENTAL CRUST THICKENING AND UPLIFTING OF THE HIMALAYAN COLLISION BELT --A MODEL FOR CONTINENTAL-CRUST TECTONIC EVOLUTION

"Backflow"is a tectono-physical process commonly occurring in continental collision zones. Based on the geological and geophysical data of the Himalayan collision belt, the authors have established a "backflow"model to expound the intrinsic relation between various geological and geophysical processes in the Himalayan collision belt and reveal the tectonic evolution regularity of continental collision zones.The "backflovv"process assumed by the authors is as follows:after the collision between the India plate and the Eurasian plate, the former continued its subduction but was hindered by cool, rigid lithospheric slab, producing a "backflow"phenomenon similar to the convection in the asthenosphere, consequently resulting in the decollement, overthrusting and supesrposition of different structural layers, the continuous heat-flow and magmatic activities, and the crust-mantle mixing."Backflow"process is one of the major mechanisms for the continental-crust thickening and uplifting of the Himalayan collision belt. Under this process, the subducted India plate was absorbed partly into the continental crust and pa.rtly into the upper mantle, leading to the thickening and imbal-anced uplifting of the continental crust of the belt.