青海治多县多彩地区巴塘群英安岩锆石U-Pb年代学及其地质意义

发布时间：2018-03-10 00:07

本文选题：锆石U-Pb年代学　切入点：甘孜-理塘缝合带　出处：《地质科技情报》2017年01期 　论文类型：期刊论文

【摘要】：多彩地区位于甘孜-理塘缝合带的北西缘,区内与甘孜-理塘缝合带演化有关的镁铁质岩、中酸性火山岩、中酸性侵入岩等岩浆岩出露较好。选取区内相关中酸性火山岩—巴塘群英安岩为研究对象,对其进行了LA-ICP-MS锆石U-Pb同位素测试,以探讨其构造背景及成岩年代学意义。测试结果表明,巴塘群英安岩的锆石U-Pb年龄为(220±1)Ma,喷出时限为晚三叠世。结合区内已有研究成果分析,得出:1巴塘群火山岩的形成表明多彩地区处于甘孜-理塘古特提斯洋向羌塘地块南西向俯冲的陆缘弧构造背景,甘孜-理塘古特提斯洋在晚三叠世时期可能仍处于俯冲消减阶段;2多彩地区与甘孜-理塘缝合带演化有关的镁铁质岩、中酸性侵入岩、中酸性火山岩的时代表现为逐渐变新的趋势。
[Abstract]:The multicolored area is located in the western margin of the Ganzi-Litang suture zone. The magnesite and intermediate-acid volcanic rocks related to the evolution of the Ganzi-Litang suture zone are located in the area. The intermediate-acid intrusive rocks and other magmatic rocks are well exposed. The LA-ICP-MS zircon U-Pb isotopic tests were carried out on the related-intermediate-acid volcanic-Batang group dolomite. In order to discuss its tectonic setting and diagenetic chronological significance, the test results show that the zircon U-Pb age is 220 卤1 Ma and the ejection time is late Triassic. It is concluded that the formation of volcanic rocks in the Batang group indicates that the multicolor area is located in the tectonic setting of the continental margin arc in the south-west subduction of the Ganzi-Litang paleoTethys ocean toward the Qiangtang block. During the late Triassic period, the Ganzi-Litang paleoTethys ocean may still be in the subduction and subduction stage. The mafic rocks and intermediate-acid intrusive rocks related to the evolution of the Ganzi-Litang suture zone may still be in the subduction and subduction stage. The epoch of intermediate-acid volcanic rocks shows a trend of gradual change.
【作者单位】：青海有色地质矿产勘查局地质矿产勘查院;中国地质大学(武汉)资源学院;长江大学地球科学学院;
【基金】：中国地质调查局项目“青海省多彩地区铜多金属矿整装勘查区关键基础地质研究”(科[2014]04-025-081)
【分类号】：P597.3;P588.1

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