摘要
帕米尔弧形构造带有巨大的地壳缩短量、近双倍的地壳增厚、巨大的海拔高程、同造山伸展作用，对塔西南新生代构造变形、沉积和古气候影响重大。但是，对于帕米尔的构造过程尚存在争议。基于前人研究成果，可将帕米尔新生代构造演化过程归结如下：印度-欧亚板块的碰撞导致帕米尔在新生代早期开始构造抬升，并在新生代晚期持续抬升。帕米尔北缘的主帕米尔逆冲断裂（MPT）和帕米尔前缘逆冲推覆系（PFT）可能在早-中中新世开始活动；东缘喀喇昆仑断裂（KKF）北段的起始活动时间在早-中中新世，喀什-叶城走滑系统（KYTS）则于晚始新世-早中新世开始活动，表明帕米尔可能在约20MaBP开始呈弧形向北挤入欧亚板块。10～7MaBP帕米尔内部的公格尔伸展系统开始发育。至上新世，KKF北段停止活动；KYTS在晚中新世或上新世的走滑速率大幅减小，表明帕米尔与塔里木板块间的相对运动量在不断减少。对于帕米尔弧形构造带形成及其演化动力学机制的更清晰界定还有赖于构造过程时空分布、造山带与盆地以及地壳浅表与地球深部过程的系统研究。
Pamir syntax, a region with vast crustal shortening, doubled crust thickness, huge topographic ele- vation, and synorogenic extension, profoundly influences the structural deformation, sedimentation and paleoclimate in southwestern Tarim basin. However, the orogenic process of the Pamir is still controversial. Based on the previ- ous research work, the Cenozoic tectonic evolution of the Pamir is summarized as follows. Due to the northward propagation of the India-Asia collision and subsequently＇south dipping subduction along the Main Pamir Thrust, the Pamir experienced tectonic uplift during the Cenozoic. The onset of thrusting and/or slipping along the Main Pamir Thrust, Pamir Frontal Thrust, northern segment of the Karakornm fault and Kashgar-Yecheng transfer system indi- cates that the northward motion of the Pamir happened at least since ca. 20 Ma BP. The east-west extension along the Kongur Shan extensional system has an initiation age of 10～7 Ma BP. The termination of slip along the north- ern segment of the Karakornm fault occurred in the Pliocene and the slip rate of the Kashgar-Yecheng transfer sys- tem decreased substantially during the late Miocene or Pliocene, possibly reflecting the substantial decrease of the relative motion magnitude between the Pamir and Tarim plate. To specifically understand the orogeny in Pamir, a couple of aspects of studies should be addressed in the future, involving the spatio-temporal variations of orogenic process, the basin-range coupling and the coupling between shallow crust and deep process.
出处
《地球科学进展》
CAS
CSCD
北大核心
2014年第8期890-902,共13页
Advances in Earth Science
基金
国家自然科学基金项目"帕米尔弧形构造带东北缘的扩展过程及构造与沉积响应"(编号:D021101)资助
