| Tectonic evolution of the Western Kunlun orogenic belt in northern Qinghai-Tibet Plateau:Evidence from zircon SHRIMP and LA-ICP-MS U-Pb geochronology |
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| 作者姓名： | ZHANG ChuanLin LU SongNian YU HaiFeng & YE HaiMin Nanjing Institute of Geology and Mineral Resources China Geological Survey Nanjing China Tianjin Institute of Geology and Mineral Resources China Geological Survey Tianjin China |
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| 作者单位： | ZHANG ChuanLin1，LU SongNian2，YU HaiFeng2 & YE HaiMin1 1 Nanjing Institute of Geology and Mineral Resources，China Geological Survey，Nanjing 210016，China; 2 Tianjin Institute of Geology and Mineral Resources，China Geological Survey，Tianjin 300170，China |
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| 基金项目： | 国家自然科学基金;中国地质调查局资助项目 |
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| 摘 要： | The Western Kunlun Range in northern Qinghai-Tibet Plateau is composed of the North Kunlun Terrane,the South Kunlun Terrane and the Karakorum-Tianshuihai Terrane. Here we report zircon SHRIMP and LA-ICP-MS U-Pb ages of some metamorphic and igneous rocks and field observations in order to pro-vide a better understanding of their Precambrian and Palaeozoic-early Mesozoic tectonic evolution. Based on these data we draw the following conclusions: (1) The paragneisses in the North Kunlun Terrane are likely of late Mesoproterozoic age rather than Palaeoproterozoic age as previously thought,representing tectonothermal episodes at 1.0―0.9 Ga and ～0.8 Ga. (2) The North Kunlun Terrane was an orogenic belt accreted to the southern margin of Tarim during late Mesoproterozoic to early Neopro-terozoic,the two episodes of metamorphisms correspond to the assemblage and breakup of Rodinia respectively. (3) The Bulunkuole Group in western South Kunlun Terrane,which was considered to be the Palaeoproterozoic basement of the South Kunlun Terrane by previous studies,is now subdivided into the late Neoproterzoic to early Palaeozoic paragneisses (khondalite) and the early Mesozoic metamorphic volcano-sedimentary series; the paragneisses were thrust onto the metamorphic vol-cano-sedimentary series from south to north,with two main teconothermal episodes (i.e.,Caledonian,460―400 Ma,and Hercynian-Indosinian,340―200 Ma),and have been documented by zircon U-Pb ages. (4) In the eastern part of the South Kunlun Terrane,a gneissic granodiorite pluton,which intruded the khondalite,was crystallized at ca. 505 Ma and metamorphosed at ca. 240 Ma. In combination with geochronology data of the paragneiss,we suggest that the South Kunlun Terrane was a Caledonian accretionary orogenic belt and overprinted by late Paleozoic to early Mesozoic arc magmatism.
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| 收稿时间： | 30 December 2005 |
| 修稿时间： | 7 June 2006 |
Tectonic evolution of the Western Kunlun orogenic belt in northern Qinghai-Tibet Plateau: Evidence from zircon SHRIMP and LA-ICP-MS U-Pb geochronology |
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| ZHANG ChuanLin,LU SongNian,YU HaiFeng & YE HaiMin Nanjing Institute of Geology and Mineral Resources,China Geological Survey,Nanjing ,China, Tianjin Institute of Geology and Mineral Resources,China Geological Survey,Tianjin ,China.Tectonic evolution of the Western Kunlun orogenic belt in northern Qinghai-Tibet Plateau:Evidence from zircon SHRIMP and LA-ICP-MS U-Pb geochronology[J].Science in China(Earth Sciences),2007,50(6):825-835. |
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| Authors: | Zhang ChuanLin Lu SongNian Yu HaiFeng Ye HaiMin |
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| Institution: | 1. Nanjing Institute of Geology and Mineral Resources, China Geological Survey, Nanjing 210016, China
2. Tianjin Institute of Geology and Mineral Resources, China Geological Survey, Tianjin 300170, China |
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| Abstract: | The Western Kunlun Range in northern Qinghai-Tibet Plateau is composed of the North Kunlun Terrane, the South Kunlun Terrane
and the Karakorum-Tianshuihai Terrane. Here we report zircon SHRIMP and LA-ICP-MS U-Pb ages of some metamorphic and igneous
rocks and field observations in order to provide a better understanding of their Precambrian and Palaeozoic-early Mesozoic
tectonic evolution. Based on these data we draw the following conclusions: (1) The paragneisses in the North Kunlun Terrane
are likely of late Mesoproterozoic age rather than Palaeoproterozoic age as previously thought, representing tectonothermal
episodes at 1.0−0.9 Ga and ∼0.8 Ga. (2) The North Kunlun Terrane was an orogenic belt accreted to the southern margin of Tarim
during late Mesoproterozoic to early Neoproterozoic, the two episodes of metamorphisms correspond to the assemblage and breakup
of Rodinia respectively. (3) The Bulunkuole Group in western South Kunlun Terrane, which was considered to be the Palaeoproterozoic
basement of the South Kunlun Terrane by previous studies, is now subdivided into the late Neoproterzoic to early Palaeozoic
paragneisses (khondalite) and the early Mesozoic metamorphic volcano-sedimentary series; the paragneisses were thrust onto
the metamorphic volcano-sedimentary series from south to north, with two main teconothermal episodes (i.e., Caledonian, 460–400
Ma, and Hercynian-Indosinian, 340–200 Ma), and have been documented by zircon U-Pb ages. (4) In the eastern part of the South
Kunlun Terrane, a gneissic granodiorite pluton, which intruded the khondalite, was crystallized at ca. 505 Ma and metamorphosed
at ca. 240 Ma. In combination with geochronology data of the paragneiss, we suggest that the South Kunlun Terrane was a Caledonian
accretionary orogenic belt and overprinted by late Paleozoic to early Mesozoic arc magmatism.
Supported by the National Natural Science Foundation of China (Grant Nos. 40303007 and 40421303) and Chinese Geology Survey
(Grant No. 200113900070) |
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| Keywords: | North Kunlun Terrane South Kunlun Terrane Precambrian basement zircon SHRIMP and LA-ICP-MS U-Pb ages tectonic implications |
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