青藏高原地壳与上地幔成层速度结构与深部层间物质的运移轨迹  

The stratificational velocity structure of crust and covering strata of upper mantle and the orbit of deep interaquifer substance locus of movement for Tibetan Plateau

作　　者：滕吉文[1] 阮小敏[1] 张永谦[1] 胡国泽[1] 闫亚芬[1] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029

出　　处：《岩石学报》2012年第12期4077-4100,共24页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(90914012);国家973项目(2008CB42570);汶川地震断裂带科学钻探项目(2008~2012)联合资助

摘　　要：在印度洋板块与欧亚板块碰撞、挤压作用下,促使深部物质重新分异、调整和运移,并导致了地壳的短缩增厚,而且造成了高原的整体隆升和深部壳、幔物质的侧向流展。基于青藏高原腹地和周边地域地壳与上地幔的成层速度结构,特别是其特异层序的展布研究表明,青藏高原地壳巨厚,但岩石圈却相对较薄;地壳中于深20±5km处存在一低速层,层速度为5.7±0.1km/s,厚度为8±2km;上地幔软流圈顶部深度为110±10km;下地壳与上地幔盖层物质以地壳低速层为上滑移面,以岩石圈漂曳的上地幔软流圈顶面为下滑移面,在印度洋板块N-NNE向力源作用下在同步运移,即形成了青藏高原腹地和周边地域特异的大陆地球动力学环境。Under the collision between India Plate and Eurasia Plate,the deep substance began to adjust and move.This results in not only the shortening and thickening of the Qinghai-Tibet Plateau,but also the lateral flow of the deep substance in crust and upper mantle.Based on the stratificational velocity structure,especially the special layers beneath the Qinghai-Tibet Plateau and its adjacent areas,the research results suggest that the crust beneath the Qinghai-Tibet Plateau is very thick,but the lithosphere of it is thin;There exists a low velocity layer with Vp of 5.7±0.1km/s and thickness of 8±2km at depth of 20±5km;The top boundary of the asthenosphere lies at depth of 110±10km;Under the force system towards N-NNE from the collision between India Plate and Eurasia Plate,the high velocity substance low crust and covering strata of upper mantle move laterally with the low velocity layer in crust as the first and the asthenosphere as the second slip interface.This eastward movement of the deep substance takes the big strike slip faults as channel boundaries and is obstructed at the north boundary of Yangtze carton.This caused the cooperation of blocks with different properties and the special deep process and geodynamical environment beneath the hinterland of Qinghai-Tibet Plateau and periphery.

关 键 词：壳、幔结构 地壳低速层 上地幔软流层 下地壳与上地幔盖层同步运移 青藏高原 

分 类 号：P313[天文地球—固体地球物理学]