Cenozoic Tectonic Uplift History of Western Qinling: Evidence from Sedimentary and Fission-Track Data  

作　　者：王修喜 Massimiliano Zattin 李吉均 宋春晖 陈述 杨成 张盛达 杨积伟 

机构地区：[1]Key Laboratory of Western China's Environmental Systems (Ministry of Education) & Research School of AridEnvironment and Climate Change, Lanzhou University [2]Dipartimento di Geoscienze, Università di Padova [3]Key Laboratory of Western China's Environmental Systems (Ministry of Education) & Research School of AridEnvironment and Climate ChangeLanzhou University [4]School of Earth Sciences, Key Laboratory of Western China's Mineral Resources of Gansu Province,Lanzhou University

出　　处：《Journal of Earth Science》2013年第4期491-505,共15页地球科学学刊（英文版）

基　　金：supported by the "Strategic Priority ResearchProgram" of the Chinese Academy of Sciences (No.XDB03020402);the National Basic Research Program (973) of China (No. 2013CB956403);the National Natural Science Foundation of China (Nos. 41201005, 41272128);the Funda-mental Research Funds for the Central Universities (No.lzujbky-2013-122);the NSFC National Innovative ResearchTeam Project (No. 41021091)

摘　　要：The western Qinling （秦岭） orogenic belt is one of the outermost ranges in the northeas- tern Tibetan Plateau. Its tectonic uplift history is therefore essential to insight on the evolution history of the plateau. However, the timing of deformation and uplift history is still poorly known. Fortunately, its Cenozoic orogenic history is recorded in an excellent synorogenic sedimentary sequence exposed in the Tianshui （天水）Ba- sin, the northeastern foot of western Qinling. Ac- cording to sedimentary-tectonic analysis of the Yaodian （尧店） and Lamashan （喇嘛山） sections based on the previous magnetostratigraphy stu- dies, we speculated that two stages （occurred at 9.2-7.4 and -3.6 Ma） of variation in depositional facies were attributed to the uplift and deforma- tion of the western Qinling, and the modern structure geomorphic frame of the northeastern Tibet formed after 2.6 Ma. Furthermore, four stages of active processes along the western Qinling occurred at 49--41, 34-27, 25-19 and -13 Ma, are deciphered from an integrated detrital apatite fission-track data of the Ganquan （甘泉）, Yaodian main sections and seven small ones. The former two are represents the exhumation episodes triggered by tectonism and the others attributed to the volcanic signals.The western Qinling （秦岭） orogenic belt is one of the outermost ranges in the northeas- tern Tibetan Plateau. Its tectonic uplift history is therefore essential to insight on the evolution history of the plateau. However, the timing of deformation and uplift history is still poorly known. Fortunately, its Cenozoic orogenic history is recorded in an excellent synorogenic sedimentary sequence exposed in the Tianshui （天水）Ba- sin, the northeastern foot of western Qinling. Ac- cording to sedimentary-tectonic analysis of the Yaodian （尧店） and Lamashan （喇嘛山） sections based on the previous magnetostratigraphy stu- dies, we speculated that two stages （occurred at 9.2-7.4 and -3.6 Ma） of variation in depositional facies were attributed to the uplift and deforma- tion of the western Qinling, and the modern structure geomorphic frame of the northeastern Tibet formed after 2.6 Ma. Furthermore, four stages of active processes along the western Qinling occurred at 49--41, 34-27, 25-19 and -13 Ma, are deciphered from an integrated detrital apatite fission-track data of the Ganquan （甘泉）, Yaodian main sections and seven small ones. The former two are represents the exhumation episodes triggered by tectonism and the others attributed to the volcanic signals.

关 键 词：CENOZOIC tectonic uplift western Qinling sedimentary sequence fission-track. 

分 类 号：P542[天文地球—构造地质学]