东昆仑都兰可可沙地区镁铁－超镁铁质杂岩的发现及其LA-ICP-MS锆石U-Pb年龄
The discovery of the mafic-ultramafic melange in Kekesha area of Dulan County, East Kunlun region, and its LA-ICP-MS zircon U-Pb age
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摘要: 提要：东昆仑地区是在经历晋宁、加里东、海西、印支等多期构造旋回之后形成的一个复合大陆造山带，其中包括多条重要的构造缝合带。近来，在东昆仑地区东段清水泉以西约15 km的可可沙及其以南地区进行1∶5万区域地质调查的过程中，发现了一套镁铁－超镁铁质杂岩。对该镁铁－超镁铁质杂岩中的辉长岩进行LA-ICP-MS锆石U-Pb同位素测年,获得（509.4±6.8）Ma（MSWD=1.4）的同位素年龄。该年龄与东昆中断裂附近的清水泉蛇绿岩的时代可以很好地对应起来，这为清水泉蛇绿岩带向西的延伸方向及东昆仑地区东段早古生代的构造演化提供了新的年代学证据。
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关键词:
- 东昆仑 /
- 都兰可可沙地区 /
- 镁铁－超镁铁质杂岩 /
- LA-ICP-MS锆石U-Pb定年
Abstract: Abstract：The East Kunlun region is a compound continental orogenic belt formed through Jinningian，Caledonian，Hercynian and Indosinian multi-stage cycles and contains quite a few important tectonic boundaries．Recently a suite of mafic-ultramafic melange was found in Kekesha area，15 km west of Qingshuiquan area, during the 1:50000 regional geological survey． The LA-ICP-MS zircon U-Pb isotopic age of the gabbro from the mafic-ultramafic melange is about（509.4±6.8）Ma（MSED=1.4），corresponding well to the age of the Qingshuiquan ophiolite near the Mid-Kunlun fault．This result thus provides new chronological evidence for the western extension of the Qingshuiquan ophiolite zone and the evolution of the eastern part of the East Kunlun region in Early Paleozoic． -
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