阿尔金—祁连山晚新生代隆升—剥露过程——来自岩屑磷灰石裂变径迹热年代学的制约  

Late Cenozoic uplift-exhumation history of the Altyn Tagh and Qilian Mountains： Evidence from detrital apatite fission track thermochronology

作　　者：徐芹芹[1,2] 季建清[2] 赵文韬[2] 孙东霞[2] 钟大赉[3] 赵磊[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]北京大学地球与空间科学学院造山带与地壳演化教育部重点实验室,北京100871 [3]中国科学院地质与地球物理研究所,北京100029

出　　处：《地质科学》2015年第4期1044-1067,共24页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家重点基础研究发展计划“973”项目（编号：2007CB411300）和中国地质调查局项目（编号：12120115070301）资助.

摘　　要：阿尔金—祁连山位于青藏高原北缘,其新生代的隆升—剥露过程记录了高原变形和向北扩展的历史,对探讨高原隆升动力学具有重要意义.本文采用岩屑磷灰石裂变径迹测年分析,利用岩屑的统计特征限定阿尔金—祁连山新生代的隆升—剥露过程.磷灰石裂变径迹测试结果表明,阿尔金—祁连山地区存在4个阶段的抬升冷却：21.1～19.4 Ma、13.5～10.5 Ma、9.0～7.3 Ma、4.3～3.8 Ma.其中,4.3～3.8 Ma抬升冷却事件仅体现在祁连山地区,9.0～7.3 Ma抬升冷却事件在区内普遍存在,且9.0～7.3 Ma隆升—剥露造就了现代阿尔金—祁连山的地貌.区域资料分析表明,9～7 Ma（或者8～6 Ma）期间,青藏高原北缘、东缘,甚至整个中国西部地区发生了大规模、区域性的抬升,中国现今“西高”的构造地貌形态可能于当时开始形成.阿尔金—祁连山地区4期抬升冷却事件与青藏高原的隆升阶段有很好的对应关系,应该是对印度—欧亚板块碰撞的响应。The Altyn Tagh and Qilian Mountains define the northern boundary of the Tibetan Plateau. Their uplift-exhumation history in the Cenozoic records the deformation and northward propagation of the Tibetan Plateau, which is important to explore the uplift dynamics of the Tibetan Plateau. Using apatite fission track （AFT） analysis on detrital samples, this paper attempts to reveal Cenozoic uplift-exhumation history of the Ahyn Tagh and Qilian Mountains statistically. AFT dating resuts suggest that the mountain ranges experienced four stages of uplift and cooling during the Late Cenozoic： 21. 1～ 19.4 Ma, 13.5～10.5 Ma, 9.0～7.3 Ma, and 4.3～3.8 Ma. The youngest cooling event only took place within the Qilian Mountain. The uplift-exhumation of 9.0～7.3 Ma was perversive in the study area, resulting in the present geomorphology of Ahyn Tagh and Qilian Mountains. Regional data show that a large-scale regional uplift of mountains in the northern and eastern edges of the Tibetan Plateau and even the whole western China occurred at 9 ～ 7 Ma （ or 8 ～ 6 Ma） at which time the ＂high-west＂ landform of China was initially formed. The four uplift and cooling events are coeval with the uplift stages of the Tibetan Plateau, which should be response to the India-Eurasia collision.

关 键 词：岩屑磷灰石 裂变径迹 隆升—剥露 地貌形态 阿尔金—祁连山 

分 类 号：P542[天文地球—构造地质学] P597[天文地球—地质学]