东秦岭—大别造山带南、北缘晚白垩世以来构造演化的石英ESR年代学研究  

Structural Evolution of Northern and Southern Edges of East Qinling-Dabie Orogenic Belt:Evidence from ESR Dating

作　　者：李学刚[1] 杨坤光[1,2] 王军[1] 

机构地区：[1]中国地质大学地球科学学院,湖北武汉430074 [2]中国地质大学构造与油气资源教育部重点实验室,湖北武汉430074

出　　处：《现代地质》2012年第2期308-316,共9页Geoscience

基　　金：国家自然科学基金项目(40972137);中国石化重大基础研究项目"中国南方中上扬子大陆构造与海相油气前景";国土资源部油气资源战略研究中心专项"南华北地区中新生代叠加构造变形与油气保存条件研究"(XQ-2007-02-3-2)

摘　　要：运用α石英热活化ESR定年法对东秦岭—大别造山带南、北缘58件样品进行了研究。结果显示,东秦岭—大别造山带南、北缘ESR年龄范围主要集中在晚白垩世以来(99.2～3.4 Ma)。结合区域地质事实分析,晚白垩世以来,东秦岭—大别造山带南缘的构造演化可划分为73.1～52.3 Ma伸展断陷期、39.1～27.2 Ma伸展-挤压的转换期和22.8～3.4 Ma挤压期;东秦岭—大别造山带北缘的构造演化可划分为89～70.1 Ma挤压隆升期、61.6～43.2 Ma伸展断陷期、37.2～22.6 Ma伸展-挤压的转换期和15.6～3.9 Ma挤压期。东秦岭—大别造山带南缘和北缘新生代构造演化特征基本相同,但是受多种因素控制,东秦岭—大别造山带南、北缘晚白垩世的构造演化存在较大差异。ESR测年结果与东秦岭—大别造山带南、北缘已有的地质事实相吻合,验证了ESR测年的可靠性。Fifty-eight samples from tectogenetic α quartz veins in northern and southern edges of East Qinling-Dabie orogenic belt were studied by the use of ESR dating method.The results show that the ESR ages of α quartz veins mainly change between 99.2 and 3.4 Ma.Combined ESR dating results with other geological evidences,it comes to the conclusion as follows：after Late Cretaceous,the evolution history of southern edge of East Qinling-Dabie orogenic belt has experienced extending and faulted depression stage（73.1-52.3 Ma）,extending-squeezing transformation stage（39.1-27.2 Ma） and squeezing stage（22.8-3.4 Ma）;the evolution history of northern edge of East Qinling-Dabie orogenic belt has experienced squeezing uplift stage（89-70.1 Ma）,extending and faulted depressions stage（61.6-43.2 Ma）,extending-squeezing transformation stage（37.2-22.6 Ma） and squeezing stage（15.6-3.9 Ma）.Northern and southern edges of East Qinling-Dabie orogenic belt have similar tectonic evolution characteristics in Cenozoic.But affected by several factors,the tectonic evolution of northern and southern edges of East Qinling-Dabie orogenic belt are obviously different in Late Cretaceous.The ESR dating results are consistent with geological evidences,which checks up the dependability of ESR dating.

关 键 词：东秦岭—大别造山带 ESR测年 新生代 构造演化 

分 类 号：P542[天文地球—构造地质学]