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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。
There has been much controversy over the comparative study of the ancient Tethyan suture in western Yunnan and Southeast Asia. Four clastic samples were collected from the Triassic Lampung group in the Chiang Rai region of Thailand for petrology, geochemistry and zircon U-Pb dating. Petrology and geochemistry studies show that the source rocks of this set of clastic rocks are mainly basic-medium rocks, a small amount of feldspathic rocks are involved, and the geotectonic background of the source rocks is island arc belt. The U-Pb dating of the oldest zircons was 3269Ma ± 29Ma, with most of the age forming three peaks: 280 ~ 250Ma, 500 ~ 440Ma and 1200 ~ 1100Ma, indicating that Triassic cluster in the Qinghai-Tibet Plateau The source areas of the debris are mainly the western strip of the volcanic belt of the Qinglai island and the Predevioric metamorphic rocks. Comparisons of the detrital zircon age maps show that, prior to the Tethyan tectonic stage, the state fabric developed similar structural-thermal events in Western Australia; after the Tethyan tectonic stage, the tectono-thermal event characteristics were closely related to the Yangtze structure Similar to the domain, it is indicated that the main ocean basin of the ancient Tethys should be west of the state of Lampang in support of the viewpoint that the Chiang Mai Tectonic Belt represents the main ocean of the ancient Tethys.