帕米尔-天山汇聚带前陆盆地重矿物组合分析及构造意义

Heavy Mineral Assemblage Analysis of the Cenozoic in the Foreland Basin of Convergence Zone of Pamir and Tianshan and its Tectonic Implication

前陆盆地沉积物记录了相邻造山带的抬升剥蚀过程,通过前陆盆地沉积物重矿物组合分析可反演相邻造山带的剥蚀历史。别尔托阔依剖面位于帕米尔-天山汇聚带前陆盆地中,其沉积物可能记录了这两个造山带的隆升和剥蚀。对该剖面新生代地层进行系统重矿物鉴定统计,获得不同层位重矿物种类及含量,分析了重矿物含量及特征指数在剖面上的变化特征。研究发现多种重矿物组合及特征指数在中新统安居安组下部发生了显著变化,可能与帕米尔在中新世早—中期的快速抬升有关。

Sediment in foreland basin records uplift and exhumation process of orogenic belts, which make it possible to inverse the exhumation history of the orogenic belts by analyzing the heavy mineral assemblage of the sediment.Bieertuokuoyi section located in the foreland basin of convergence zone of Pamir and Tianshan.Its Cenozoic sediments recoded uplift and exhumation of the two orogenic belts.In this study, we analyzed the heavy minerals of the Cenozoic of Bieertuokuoyi seciton in the foreland basin.We got the species and contents of the heavy minerals in different layers and analyzed the change tendency upward of contents of these heavy minerals.We found that the heavy mineral assemblages had a significant change at Miocene Anju＇ an Formation.This might be related to the rapid uplift of North Pamir in early-m iddie Miocene.