阿尔金断裂带中中新世以来构造变形的电子自旋共振测年证据  

Evidences from ESR Dating for Structural Deformation of Altyn Tagh Fault System Since Middle Miocene

作　　者：李萌[1,2] 汤良杰[1,2] 邱海峻[3] 王鹏昊[4] 甄素静 

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]中国石油大学(北京)盆地与油藏研究中心,北京102249 [3]国土资源部油气资源战略研究中心,北京100034 [4]中国石油新疆油田公司勘探开发研究院,新疆克拉玛依834000

出　　处：《地球科学与环境学报》2015年第1期57-65,共9页Journal of Earth Sciences and Environment

基　　金：国家重点基础研究发展计划("九七三"计划)项目(2012CB214804);国土资源部全国油气资源战略选区调查与评价项目(2009GYXQ02-05);国家科技重大专项项目(2011ZX05002-003-001);中国石化西北油田分公司项目(KY2010-S-053)

摘　　要：阿尔金断裂带新生代以来大规模活动的时限及规律一直是国内外研究的热点问题之一,但目前仍缺乏可靠的年代学约束。在野外地质调查基础上,对阿尔金断裂带中的伴生石英脉和石膏采用电子自旋共振(ESR)测年,并用测年结果约束断裂活动起始时间的下限,最后探讨了阿尔金断裂带中中新世以来的构造活动。结果表明:阿尔金断裂带新生代大规模构造变形始自中中新世((12.5±1.3)^(15.1±1.5)Ma),之后经历了多期次的构造变形活动;阿尔金主断裂开始大规模走滑活动的时限至少始于(15.1±1.5)Ma,而阿尔金北缘断裂挤压逆冲活动的时限至少始于(14.1±1.4)Ma;阿尔金断裂带的变形活动在其主体走滑和北缘逆冲之间存在时间差,推测其具有从中心向两侧渐进扩展的变形方式;深部的韧性剪切首先引起阿尔金主断裂的走滑位移,致使附近山体快速抬升,随后变形扩展并引起阿尔金北缘断裂逆冲活动的构造响应。The study on the initial activity time and mechanism of Altyn Tagh fault system since Cenozoic is one of hot topics in the northern Tibet Plateau,but is still lack of a reliable chronological constraint.Based on field investigation,the ages of associated quartz vein and gypsum from Altyn Tagh fault system were measured by electron spin resonance（ESR）dating,and the age was taken as the constraint of the latest fault activity;the structural deformation of Altyn Tagh fault system since Middle Miocene was discussed.The results show that Cenozoiclarge-scale structural deformation of Altyn Tagh fault system starts in Middle Miocene（（12.5±1.3）-（15.1±1.5）Ma）,followed by multistage activities;time limit of large-scale strike-slip activity for Altyn Tagh main fault at least starts in（15.1±1.5）Ma,but time limit of compression thrust activity for the northern Altyn Tagh fault at least starts in（14.1±1.4）Ma;there is a time difference for the activity between Altyn Tagh main fault and the northern Altyn Tagh fault,suggesting that Altyn Tagh fault system extends progressively from the center to both sides;the deep ductile shear leads to strike-slip movement of Altyn Tagh main fault and rapid uplift of neighbouring mountain,and then the deformation propagation cause the tectonic response of thrust activity of the northern Altyn Tagh fault.

关 键 词：构造变形 电子自旋共振测年 中中新世 起始时间 流体活动 渐进扩展 阿尔金断裂带 

分 类 号：P542[天文地球—构造地质学]