青海东昆仑东山根矿区构造活动的磷灰石裂变径迹分析  

Apatite fission track analysis of tectonic activity in the Dongshangen mining area,East Kunlun,Qinghai-Tibet Plateau

作　　者：陈雪 袁万明 袁二军 王珂 冯子睿 CHEN Xue;YUAN Wanming;YUAN Erjun;WANG Ke;FENG Zirui(Institute of Earth Sciences,China University of Geosciences(Beijing),Beijing 100083,China;Department of Geological Engineering,Qinghai University,Xining 810016,China)

机构地区：[1]中国地质大学(北京)科学研究院,北京100083 [2]青海大学地质工程系,青海西宁810016

出　　处：《地学前缘》2018年第6期330-337,共8页Earth Science Frontiers

基　　金：国家自然科学基金重点项目(41730427);国家重点基础研究发展计划“973”项目(2015CB452606);中国地质调查局地质调查工作项目(基2011-03-04-06);青海省地质调查局地勘基金项目“青海省东昆仑斑岩成矿规律研究与找矿靶区预测”

摘　　要：对青海东昆仑东山根矿区所采集的7个磷灰石样品进行分析,所获得的磷灰石裂变径迹年龄分布在136-67 Ma,具体分为136-112 Ma、101-95 Ma和74-67 Ma 3个年龄组,这较好地体现了该地区所经历的构造隆升事件。东山根矿区热历史可分为4个阶段:第1阶段(160-80 Ma),是羌塘地块与拉萨地块发生向欧亚板块挤压拼贴作用的响应阶段;第2阶段(120-80 Ma),经历了阿尔金断裂走滑,青藏高原北部隆升,以及燕山晚期冈底斯地体向北俯冲运动,直到早白垩世晚期发生快速冷却抬升;第3阶段(80-23 Ma),构造事件相对平稳,整体呈轻微抬升,样品随地质体隆升缓慢降温;第4阶段(23 Ma至今),快速冷却抬升,对应印度板块对欧亚板块的碰撞作用。Through the analysis of seven apatite samples collected from the Dongshangen mining area of east Kunlun Mountain,Qinghai Province,we showed that the apatite fission track ages vary from 136 to 67 Ma.The ages can be divided into three groups of 136-112,101-95 and 74-67 Ma to better reflect the uplifting and exhumation events occurred in this region.The thermal history of the Dongshangen mining area are delineated into four stages by fission track modeling.The first stage(160-120 Ma)corresponds to the compressive movement of both the Qiangtang and Lhasa blocks towards the Eurasian Plate.The second stage(120-15 Ma)coincides with the Aerjin fault strike-slip,the northern Tibetan Plateau uplifting and the northward subduction movement of the Gangdese block in the Late Yanshan period.This stage experienced rapid cooling and uplifting until the end of the Early Cretaceous.In the third stage(80-23 Ma)the region was relatively stable,cooling down slowly,while the fourth stage(23 Ma to present)undergoes rapid cooling and uplifting,corresponding to the collision of the Indian Plate towards the Eurasian Plate.

关 键 词：构造活动 热历史 裂变径迹 磷灰石 东昆仑 

分 类 号：P542[天文地球—构造地质学] P597.3[天文地球—地质学]