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现代地质 ›› 2020, Vol. 34 ›› Issue (01): 40-50.DOI: 10.19657/j.geoscience.1000-8527.2019.011

• 岩石学 • 上一篇    下一篇

内蒙古别鲁乌图铜多金属矿床锆石U-Pb年龄和S、Pb同位素特征及其地质意义

郭硕(), 何鹏, 刘洋, 滕飞, 胡晓佳, 王文龙, 杨泽黎   

  1. 中国地质调查局 天津地质调查中心,天津 300170
  • 收稿日期:2018-07-09 修回日期:2019-10-30 出版日期:2020-03-05 发布日期:2020-03-07
  • 作者简介:郭 硕,男,工程师,1989年出生,矿物学、岩石学、矿床学专业,主要从事区域地质及矿床地球化学研究。Email: shuoguo89@sina.com
  • 基金资助:
    中国地质调查局地质调查项目“内蒙古温都尔庙—镶黄旗地区区域地质调查项目”(DD20190038);“京西冀北煤矿区综合地质调查与评价项目”(DD20190821)

Zircon U-Pb Age and S-Pb Isotope Features of the Bieluwutu Copper-polymetallic Deposit and Their Geological Significance

GUO Shuo(), HE Peng, LIU Yang, TENG Fei, HU Xiaojia, WANG Wenlong, YANG Zeli   

  1. Tianjin Center of Geological Survey, China Geological Survey, Tianjin 300170, China
  • Received:2018-07-09 Revised:2019-10-30 Online:2020-03-05 Published:2020-03-07

摘要:

为了明确内蒙古别鲁乌图铜多金属矿床的成矿年龄与矿床成因,对该矿床中与成矿关系密切的流纹岩进行了锆石U-Pb年龄以及主要金属硫化物的S、Pb同位素测试。其中流纹岩的锆石206Pb/238U加权平均年龄为(271.7±1.6) Ma(MSWD=1.02),显示成矿作用发生于二叠纪。金属硫化物的S同位素分析结果显示δ34SV-CDT值分布在-0.6‰~1.0‰之间,平均为0.49‰,变化范围较窄,显示S的来源单一;Pb同位素组成比较集中,206Pb/204Pb为18.207~18.674,207Pb/204Pb为15.620~15.699,208Pb/204Pb为38.144~38.790,具有壳幔混源的特征。S、Pb同位素特征均指示成矿物质主要来源于岩浆热液。结合区域地质、矿床地质、空间分带等特征以及S、Pb同位素组成可知,别鲁乌图铜多金属矿床为VHMS型矿床,形成于二叠纪陆缘弧裂谷中。

关键词: 别鲁乌图, VHMS型矿床, 锆石U-Pb年龄, 二叠纪, S同位素, Pb同位素

Abstract:

To clarify the metallogenic age and genesis of the Bieluwutu copper-polymetallic deposit, zircon U-Pb age of the ore-related rhyolite and sulfide S-Pb isotopes were analyzed. The weighted mean zircon 206Pb/238U age of the rhyolite is (271.7±1.6) Ma (MSWD=1.02). This suggests that the ore-related rhyolite and the Bieluwutu copper-polymetallic deposit was formed in the Permian. Sulfur isotope data show that the δ34SV-CDT variation is small (-0.6‰ to 1.0‰, average 0.49‰), implying that the sulfur may have come from a single source. The sulfide lead isotope compositions are relatively consistent, i.e., 206Pb/204Pb (18.207-18.674), 207Pb/204Pb (15.620-15.699) and 208Pb/204Pb (38.144-38.790), featuring a mixed crust-mantle source. These S-Pb isotopic compositions indicate that the ore-forming materials were principally originated from magmatism. Evidence from regional and local geology, mineralization zonation and sulfur and lead isotopes support that the Bieluwutu copper-polymetallic deposit belongs to VHMS-type and was formed in an intra-arc rift during the Permian.

Key words: Bieluwutu, VHMS deposit, zircon U-Pb dating, Permian, sulfur isotope, lead isotope

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