新近纪早期青藏高原北部构造隆升研究进展

A Review of the Neogene Tectonic Evolution of the Northern Tibetan Plateau

新生代以来,随着印度板块与欧亚大陆发生碰撞,引起了亚洲大陆古生代和中生代的古老构造带的再次活化。青藏高原北缘的基岩和沉积盆地内的碎屑沉积物详细地记录了不同时期的构造隆升情况。本文利用盆山耦合的思想,通过对青藏高原北缘的低温热年代学、沉积学的研究结果汇总,结合区域内盆地沉降、大型走滑和逆冲断裂的活动时间,发现青藏高原北缘在早–中中新世经历了快速的隆升过程。在高原西北缘主要通过陆内地壳缩短、塔吉克–塔里木盆地基底向南深俯冲、主帕米尔–喀什叶城转换体系–喀喇昆仑断裂的活动来吸收和调节地形变形;在东北端,主要依靠阿尔金走滑断裂的迁移发生的侧向移动,所引起的陆内俯冲作用、地壳缩短过程来实现。青藏高原北部的地质框架在新近纪早期开始初步建立。

The Indian plate has collided with the Eurasia since the early Cenozoic, which reactivated the Paleozoic and Mesozoic tectonic belts in the Central Asia. The low-temperature thermochronology and detrital sediments from the bedrocks and sedimentary basins can be used to constrain the up-lifting time of mountains at different periods around the northern margin of Tibetan Plateau. In this study, based on the conception of basin-range coupling, we have summarized the results of thermochronology and sedimentology, coupled with the active timing of the basin subsidence and large-scale reversed and strike-slip faults to show that the fast tectonic uplift can be found at early-middle Miocene. The deformations had been accommodated by the intro-continental crustal shortening, basin subduction, large-scale thrusting and strike-slip faults movement in the north-west margin of Tibetan Plateau. In contrast, the Altyn Tagh strike-slip fault had migrated north-eastwards that actuated the intro-continental subduction and crustal shortening paying the important role to accommodate the tectonic stress in the northeastern part of Tibetan Plateau. The geological framework has been built in the northern edge of Tibetan Plateau at early Neogene.