| Cenozoic Magmatism and Tectonic Framework of Western Yunnan, China: Constrained from Geochemistry, Sr–Nd–Pb Isotopes and Fission Track Dating |
| |
| 作者姓名： | YANG Xin XU Xuhui ZHANG Zhongpei LIU Yifeng ZHANG Jibiao LIU Xingwang XIONG Ping ZHENG Jianjing |
| |
| 作者单位： | 1 SINOPEC Petroleum Exploration and Development Research Institute, Beijing 100083, China;2 Gansu Provincial Key Laboratory of Petroleum Resources; Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou 730000, China;3 Wuxi Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China;4 State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Beijing 102249, China |
| |
| 基金项目： | We thank Dr. Guo Jianmin and Dr. Wang Yadong for their assistance with our field work, and Dr. Li Shihu for discussions that assisted in improving our recognition of the geological background. |
| |
| 摘 要： | Western Yunnan is composed of several extruded continental microblocks that were generated by the oblique collision between the Indian and Asian continents during the Cenozoic. In this study, the magmatic and tectonic frameworks of western Yunnan in the Cenozoic were analyzed based on geochemistry, Sr–Nd–Pb isotopes, and apatite/zircon fission track dating. Magmatism during the Cenozoic in western Yunnan was then divided into three distinctive episodes: alkali granite rocks produced from 55 to 46 Ma were derived from the anatexis of crustal materials; bimodal igneous rocks formed between 37 and 24 Ma were possibly derived from an EMII mantle with a contribution from continental materials; and intermediate–basic volcanic rocks produced in the Tengchong microblocks since ~16 Ma are considered to be generated by the partial melting of the upper mantle that was induced by the pulling apart of the dextral Gaoligong strike–slip fault system. Moreover, fission track analysis of apatite and zircon indicates that the regional crustal uplift in western Yunnan possibly began at ~34 Ma, with accelerated annealing occurring at ~24 Ma, ~13 Ma, and ~4 Ma. During the past 24 Ma, the average denudation rate was ~0.32 mm/yr for the faulted block controlled by the Chongshan–Lancang River fault. However, crustal uplift has been relatively gentle in places lacking influence from strike–slip shear zones, with an average denudation rate of ~0.2 mm/yr. Combined with strike–slip shear and block rotation in the Cenozoic, the tectonic evolution of western Yunnan since ~45 Ma can thus be divided into four stages occurring at 45–37 Ma, 37–24 Ma, 24–13 Ma, and 13–0 Ma.
|
| 关 键 词： | Magmatism Geochemistry Fission Track Dating Cenozoic Western Yunnan |
| 收稿时间： | 2014/12/12 0:00:00 |
| 修稿时间： | 2016/5/16 0:00:00 |
Cenozoic Magmatism and Tectonic Framework of Western Yunnan,China: Constrained from Geochemistry,Sr–Nd–Pb Isotopes and Fission Track Dating |
| |
| Authors: | YANG Xin XU Xuhui ZHANG Zhongpei LIU Yifeng ZHANG Jibiao LIU Xingwang XIONG Ping and ZHENG Jianjing |
| |
| Institution: | 1 SINOPEC Petroleum Exploration and Development Research Institute, Beijing 100083, China;2 Gansu Provincial Key Laboratory of Petroleum Resources; Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou 730000, China;3 Wuxi Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China;,3 Wuxi Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China,1 SINOPEC Petroleum Exploration and Development Research Institute, Beijing 100083,4 State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Beijing 102249, China,1 SINOPEC Petroleum Exploration and Development Research Institute, Beijing 100083,2 Gansu Provincial Key Laboratory of Petroleum Resources; Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou 730000, China,1 SINOPEC Petroleum Exploration and Development Research Institute, Beijing 100083 and 2 Gansu Provincial Key Laboratory of Petroleum Resources; Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou 730000, China |
| |
| Abstract: | Western Yunnan is composed of several extruded continental microblocks that were generated by the oblique collision between the Indian and Asian continents during the Cenozoic. In this study, the magmatic and tectonic frameworks of western Yunnan in the Cenozoic were analyzed based on geochemistry, Sr–Nd–Pb isotopes, and apatite/zircon fission track dating. Magmatism during the Cenozoic in western Yunnan was then divided into three distinctive episodes: alkali granite rocks produced from 55 to 46 Ma were derived from the anatexis of crustal materials; bimodal igneous rocks formed between 37 and 24 Ma were possibly derived from an EMII mantle with a contribution from continental materials; and intermediate‐basic volcanic rocks produced in the Tengchong microblocks since ～16 Ma are considered to be generated by the partial melting of the upper mantle that was induced by the pulling apart of the dextral Gaoligong strike‐slip fault system. Moreover, fission track analysis of apatite and zircon indicates that the regional crustal uplift in western Yunnan possibly began at ～34 Ma, with accelerated annealing occurring at ～24 Ma, ～13 Ma, and ～4 Ma. During the past 24 Ma, the average denudation rate was ～0.32 mm/yr for the faulted block controlled by the Chongshan–Lancang River fault However, crustal uplift has been relatively gentle in places lacking influence from strike‐slip shear zones, with an average denudation rate of ～0.2 mm/yr. Combined with strike‐slip shear and block rotation in the Cenozoic, the tectonic evolution of western Yunnan since ～45 Ma can thus be divided into four stages occurring at 45–37 Ma, 37–24 Ma, 24–13 Ma, and 13–0 Ma. |
| |
| Keywords: | Magmatism Geochemistry Fission Track Dating Cenozoic Western Yunnan |
| 本文献已被 CNKI 等数据库收录！ |
| 点击此处可从《Acta Geologica Sinica》浏览原始摘要信息 |
| 点击此处可从《Acta Geologica Sinica》下载免费的PDF全文 |
|
