藏北改则康托盆地逆冲推覆构造磷灰石裂变径迹年代学制约  

Apatite fission track constraint on thrust faults in Kangtuo Basin,northern Tibet

作　　者：于俊秋 吴珍汉[2] 赵珍[2] 季长军[2] 于俊博 康健 YUjunqiu;WU Zhenhan;ZHAO Zhen;Jl Changjun;YUjunbo;KANGJian(China University of Geosciences,Beijing 100083,China;Chinese Academy of Geological Sciences,Beijing 100037,China;No.3 Gld Geological Party,China People Armed Police Force,Harbin 150006,Heilongiang,China;Earthquake Administration of Heilongiang Province,Harbii 150090,Heilongiang,China)

机构地区：[1]中国地质大学(北京),北京100083 [2]中国地质科学院,北京100037 [3]武警黄金三支队,黑龙江哈尔滨150086 [4]黑龙江地震局,黑龙江哈尔滨150090

出　　处：《地质通报》2018年第6期987-995,共9页Geological Bulletin of China

基　　金：中国地质调查局项目<羌塘盆地隆鄂尼-鄂斯玛地区油气地质构造调查>(编号:DD20160161)

摘　　要：对采自羌塘地块南部改则地区康托盆地的碎屑岩及火山岩进行磷灰石裂变径迹年代学测试及AFT热历史模拟,获得77±6Ma、62±5Ma、44±3Ma、35±2Ma四组磷灰石裂变径迹年龄,平均径迹长度介于11.6±2.0~13.3±1.9μm之间。AFT热历史模拟结果指示,研究区自晚白垩世至现今主要历经了3次构造抬升冷却过程:晚白垩世(100~65Ma)快速隆升剥蚀阶段,其降温速率和隆升速率分别为1.46~4.26℃/Ma、0.05~0.14mm/a,该事件为新特提斯洋洋壳沿雅鲁藏布江俯冲作用的响应;始新世中期(50~35Ma)快速隆升剥蚀阶段,该阶段降温幅度相对以第一次较小,该构造事件与印度大陆的向北俯冲具有成因联系;20Ma至现今的快速抬升冷却阶段为青藏高原整体拉张走滑构造环境所影响,其隆升速率和降温速率分别为3.25~6.0℃/Ma、0.03~0.2mm/a。Four rock samples collected from the Kangtuo Basin in northern Tibetan Plateau were used to deterrmne the apatite fission track ages. Results of all the samples show that the individua grains belong to a single populat ion wi th a single mean age and have central ages of 77±6Ma, 6 2 ± 5Ma, 4 4 ± 3M a and 3 5± 2Ma . The ir mean track lengths are 11.6 ± 2.0 -13.3 ± 1.9 μm Wth a single peak.The authors used therma history simulation software AFT Solve to simulate the therma history of the three important stages of tectonic movement in Kanguo Basin since Late Mesozoic. From 100Ma t ion rates were 1.46-4 .26℃ /Ma and 0.05-0.14μm /a respectively. Com bined with field con di tion and sions have been reached： The Cretaceous tectonic uplift event was influenced by the subduction of the Yarlung Zangbo River . Thesecond tectonic movement took place between 50Ma and 35Ma and its intensity was weaker than that of the first onetectonic uplift event was related to Indo-Eurasian co oision. Since 20Ma, the cooling and denudat ion ratesand 0.03-0.2 n im/a respectively, and this te ctonic mo vemen t has been influenced by the Cenozoic who le uplifting strike-slip environment in Tibet.

关 键 词：磷灰石裂变径迹 逆冲推覆构造 康托盆地 藏北改则 

分 类 号：P619.213[天文地球—矿床学] P597.3[天文地球—地质学]