| 泰国清莱地区三叠纪南邦群碎屑锆石LA-ICP-MSU-Pb年龄及其地质意义 |
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| 引用本文： | 高海龙,;冯庆来,;聂小妹,;CHONGLAKMANI Chongpan,;MONJAI Denchok.泰国清莱地区三叠纪南邦群碎屑锆石LA-ICP-MSU-Pb年龄及其地质意义[J].中国区域地质,2014(7):995-1007. |
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| 作者姓名： | 高海龙 ;冯庆来 ;聂小妹 ;CHONGLAKMANI Chongpan ;MONJAI Denchok |
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| 作者单位： | [1]中国地质大学地质过程与矿产资源国家重点实验室,湖北武汉430074; [2]School of Geotechnology, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand |
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| 基金项目： | 国家自然科学基金项目（批准号：41172202、41190073）; 地质过程与矿产资源国家重点实验室项目（编号：GPMR201401）
致谢：成文过程中与东南亚特提斯地质研究小组成员进行了有益的讨论,审稿专家提出了建设性意见,在此一并表示感谢. |
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| 摘 要： | 对于中国滇西和东南亚地区古特提斯缝合带对比一直存在诸多争议。在泰国清莱地区三叠纪南邦群中采集4件碎屑岩样品,进行岩石学、地球化学和锆石U-Pb测年研究。岩石学和地球化学研究表明,该套碎屑岩的源岩主要为基性—中基性岩石,卷入少量长英质岩石,物源区大地构造背景为岛弧带。所测得最古老锆石U-Pb同位素年龄为3269Ma±29Ma,绝大多数年龄集中形成3个峰值：280～250Ma、500～440Ma和1200～1100Ma,指示清莱地区三叠纪南邦群碎屑物源区主要为清莱岛弧火山岩带西部条带和前泥盆纪变质岩系。碎屑锆石年龄图谱的对比结果表明,原特提斯构造阶段之前,南邦地体与西澳大利亚发育类似构造—热事件;在原特提斯构造阶段之后,其构造—热事件特征与扬子构造域相类似,指示古特提斯洋的主洋盆应该在南邦地体以西,支持清迈构造带代表古特提斯主洋盆的观点。
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| 关 键 词： | 碎屑锆石U-Pb年龄 清莱岛弧火山岩带 物源分析 古特提斯演化 缝合带 |
LA-ICP-MS U-Pb isotopic ages of the Triassic Lampang Group in ChiangRai area,Thailand and their geological significance |
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| Institution: | GAO Hai-long,FENG Qing-lai,NIE Xiao-mei,CHONGLAKMANI Chongpan,MONJAI Denchok(1. State Key Laboratory of Geological Process and Mineral Resources, China University of Geosciences, Wuhan 450074, Hubei, China; 2. School of Geotechnology, Suranaree University of Technology, Nakhon Ratchasima 50000, Thailand) |
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| Abstract: | There have long been many controversies about the correlations between Paleo-Tethyan geosutures in western Yunnan Province of China and Southeast Asia. In this paper, the petrography, geochronology, and geochemistry were studied by using four samples collected from the Triassic Lampang Group in ChiangRai area. The results suggest that the source rocks of the clastic rocks are basic-intermediate rocks, with the addition of some felsic rocks. The tectonic setting of the source area is island arc. The oldest zircon U-Pb isotopic age is 3269Ma±29Ma. Other ages show three significant peaks： 280～250Ma, 500～440Ma and 1200～1100Ma. These age peaks indicate that the main sources of the Triassic Lampang Group in the study area are ChiangRai volcanic belt and pre-Devonian metamorphic rocks in the west, with the supply of small amounts of clastic materials from the volcanic arc belts in the eastern part of the study area. The comparison between detrital zircon age spectrums shows that, before the Proto-Tethys phase,there were similar tectonic-thermal events in Lampang terrane and Western Australia. In the Proto-Tethys phase and the subsequent period, the tectonic-thermal events in Lampang terrane and Yangtze plate were similar to each other, indicating that the main PaleoTethys ocean basin should be in the west of Lampang terrane, which supports the viewpoint that ChiangMai tectonic zone represents the main ocean basin of Paleo-Tethys. |
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| Keywords: | detrital zircon U-Pb age ChiangRai island arc volcanic belt source analysis Paleo-Tethys |
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