新疆富蕴县西部出露一套变质基性火山岩,主要岩性为斜长角闪岩,呈透镜状分布,是古生代增生混杂岩带的组成部分.地球化学特征表明,其具有典型的大洋拉斑玄武岩(N-MORB型玄武岩)的地球化学特点.运用LA-ICP-MS方法,对斜长角闪岩中的锆石进行了U-Th-Pb同位素分析.测年结果显示,斜长角闪岩的形成时代为437Ma±12Ma,为早志留世.对玛因鄂博蛇绿岩的研究为进一步探讨斋桑-额尔齐斯蛇绿构造岩带、建立该区古生代构造格架、讨论其地质演化史提供了新的资料依据.%A series of metabasic volcanic rocks are exposed in the west of Fuyun Country, Xinjiang. They are composed mostly of plagioclase amphibolite and occured in the lenticular form in Fuyun Rock Group. Geochemical studies indicate that these metabasic volcanic rocks have characteristics of N-type MORB (mid-ocean ridge basalt). LA-ICP-MS zircon U-Pb dating analysis was performed for metabasic volcanic rocks in the west of Fuyun Country, and the results showed that the formation age of the plagioclase amphibolite is 437±12Ma, suggesting Early Silurian. The study of Mayinebo ophiolite provides new supplementary information for the investigation of Zayson-Ertix ophiolic tectonic rock zone and its geological evolution history as well as for the establishment of its Paleozoic tectonic framework in this area.
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