内蒙古黄花滩铜镍矿区辉长岩LA-ICP-MS锆石U-Pb定年及地球化学特征

发布时间：2018-05-24 21:45

  本文选题：内蒙古黄花滩铜镍矿区 + 辉长岩　； 参考：《岩矿测试》2016年02期

【摘要】：在乌拉特后旗—达茂旗—四子王旗一带的内蒙古中部地区分布着超基性-酸性连续岩浆系列,开展其岩体年代学、地球化学研究可为内蒙古中部地区与超基性-基性岩有关的铜镍矿成矿规律研究提供基础地质资料,还可以推断岩浆侵位时期的区域大地构造背景。本文以达茂旗黄花滩铜镍矿区出露的辉长岩为研究对象,采用LA-ICP-MS仪器对无裂隙、高透明度、阴极发光均匀、环带清晰的锆石进行U-Pb定年,获得岩体加权平均年龄为262.4±1.1 Ma,并利用XRF和ICP-MS进行岩石地球化学分析显示黄花滩辉长岩具有后碰撞拉伸环境下的岩浆特征。综合前人相关研究认为,内蒙古中部地区于中二叠世晚期(255~275 Ma)已经进入后碰撞构造阶段,而古亚洲洋在该区域的闭合应发生在晚二叠世前(~285 Ma),此结论丰富了古亚洲洋闭合时间上限及中晚二叠世期间内蒙古中部地区构造背景方面的证据。
[Abstract]:In the central part of Inner Mongolia, the ultrabasic-acid continuous magma series is distributed in the area of Wulatou Banner, Damao Banner and Siziwang Banner, and its geochronology is carried out. The geochemical study can provide basic geological data for the study of copper-nickel metallogenic regularity related to ultrabasic-basic rocks in the central part of Inner Mongolia, and can also infer the regional tectonic setting during the magmatic emplacement period. In this paper, the exposed gabbro from Huanghuatan Copper and Nickel Mine of Damao Banner is taken as the research object. The zircon with no fissure, high transparency, uniform cathodic luminescence and clear annulus is used for U-Pb dating by using LA-ICP-MS instrument. The weighted mean age of the rock mass is 262.4 卤1. 1 Ma.The geochemistry analysis by XRF and ICP-MS shows that the Huanghuatan gabbro has the characteristics of magma in the post-collisional extensional environment. Based on previous studies, it is concluded that the central part of Inner Mongolia has entered the post-collision tectonic stage since the late Middle Permian. The closure of the Paleo-Asian Ocean in the region should have occurred at 285 Mai before the late Permian. This conclusion enriches the upper limit of the closure time of the Paleo-Asian Ocean and the evidence of tectonic setting in the central part of Inner Mongolia during the Middle and late Permian.
【作者单位】： 中国地质科学院研究生部;中国地质调查局天津地质矿产研究所;内蒙古自治区地质调查院;中国地质科学院地质研究所;
【基金】：国家国际科技合作项目(2012DFB20220) 中国地质调查局项目(1212010561510,1212010811061)
【分类号】：P597.3;P618.41;P618.63
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本文编号：1930674