帕米尔东北缘新生代隆升活动:来自奥依塔格剖面砾石统计的证据

砾岩相通常作为构造事件的标志，对探讨造山带隆升过程有着重要的意义.选取位于帕米尔构造带东北缘的奥依塔格剖面开展砾石统计分析.新生代不同时期砾石的统计结果显示，奥依塔格剖面砾石成分主要为火成岩和变质岩，这与帕米尔造山带岩性相符.其中，花岗岩砾石作为特征组分首次出现在上新统阿图什组底部.砾石主要为巨砾，且以长短轴比值为1~2的近圆状为主；砾石的磨圆度中等，绝大部分为次磨圆-次棱角状；分选中等-差.结合砾石所处地层的沉积环境和热年代学记录，认为帕米尔东北缘新生代可能存在3期构造隆升事件，包括渐新-中新世克孜洛依组沉积早期、中新世中期(安居安组中-上段和帕卡布拉克组下段沉积时期)和上新世以来(阿图什组下段沉积以来). 

Cenozoic Uplift of the Northeastern Pamir: Evidence from the Gravel Counting Results of the Oytag Section

The study of gravel-facies, an important sedimentary indicator of tectonic event could facilitate the understanding of the evolution of the uplift in orogen. In this paper, the Cenozoic gravels in Oytag section located in the piedmont of northeastern Pamir, has been chosen to conduct gravel counting. The results show that gravels in Cenozoic are mainly igneous and metamorphic, indicating that they came from Pamir area. As the first occurrence of new gravel types, the granite gravel emerges at the bottom of Atushi Formation of Pliocene. The gravels are mainly of giant-size, sub-rounded and sub-angular, moderated and middling to bad sorted, with a ratio of the length of maximum axis to the minimum axis ranging from 1 to 2. Combined with Cenozoic depositing environment and thermochronology records, following uplifting periods have been identified in northeastern Pamir as Late Oligocene to Early Miocene, Mid Miocene and since Early Pliocene.