张明超, 陈仁义, 李景朝, 李永胜, 姚磊, 陈辉, 来守华, 王涛. 江苏栖霞山铅锌多金属矿床深部碳-氧-锶同位素地球化学特征及其指示意义[J]. 地质通报, 2019, 38(9): 1529-1542.
    引用本文: 张明超, 陈仁义, 李景朝, 李永胜, 姚磊, 陈辉, 来守华, 王涛. 江苏栖霞山铅锌多金属矿床深部碳-氧-锶同位素地球化学特征及其指示意义[J]. 地质通报, 2019, 38(9): 1529-1542.
    ZHANG Mingchao, CHEN Renyi, LI Jingchao, LI Yongsheng, YAO Lei, CHEN Hui, LAI Shouhua, WANG Tao. Carbon, oxygen and strontium isotope geochemical characteristics of the Qixiashan Pb-Zn polymetallic deposit, Jiangsu Province, and their indication significance[J]. Geological Bulletin of China, 2019, 38(9): 1529-1542.
    Citation: ZHANG Mingchao, CHEN Renyi, LI Jingchao, LI Yongsheng, YAO Lei, CHEN Hui, LAI Shouhua, WANG Tao. Carbon, oxygen and strontium isotope geochemical characteristics of the Qixiashan Pb-Zn polymetallic deposit, Jiangsu Province, and their indication significance[J]. Geological Bulletin of China, 2019, 38(9): 1529-1542.

    江苏栖霞山铅锌多金属矿床深部碳-氧-锶同位素地球化学特征及其指示意义

    Carbon, oxygen and strontium isotope geochemical characteristics of the Qixiashan Pb-Zn polymetallic deposit, Jiangsu Province, and their indication significance

    • 摘要: 以栖霞山铅锌多金属矿床深部找矿钻孔岩心为对象,开展碳-氧-锶同位素地球化学研究。结果表明,栖霞山矿床矿石样品δ13CV-PDB同位素值为-5.1‰~1.9‰,且由浅部至深部,矿石样品的δ13C、δ18O值处于增大的趋势,指示成矿流体中的碳起源于碳酸盐岩、源自地幔和岩浆的深源碳。对锶同位素的研究显示,栖霞山矿石87Sr/86Sr值为0.704816~0.71405,部分大于矿体围岩黄龙组灰岩的87Sr/86Sr值(0.708329~0.709685),部分小于矿体围岩黄龙组灰岩的87Sr/86Sr值,并与不同来源的Sr同位素对比,揭示栖霞山矿石中Sr兼具基底地层Sr和幔源Sr的混合来源特征,且在围岩蚀变过程中87Sr/86Sr的变化应主要由成矿流体引起。结合本区成矿地质特征认为,栖霞山矿床成矿流体可能来自花岗岩的期后热液,在热动力作用下,流经元古宇基底地层,形成具有混合物质来源的成矿流体,成矿作用过程主要为成矿流体与围岩碳酸盐岩发生水-岩反应所致。

       

      Abstract: In this paper, the authors carried out the study of the carbon-oxygen-strontium isotope geochemistry of the samples from deep holes during the mineral prospecting work in the Qixiashan Pb-Zn polymetallic deposit. The results show that the δ13CV-PDB values for ore samples from the Qixiashan deposit vary from -5.1‰ to 1.9‰. From the shallow part downward, the δ13C and δ18O values of ore samples are in an increasing trend, which indicates that the carbon in the ore-forming fluids originated from the carbonate rocks and from the deep source of carbon in the mantle and magma. In the study of strontium isotope, the 87Sr/86Sr values of ore samples from the Qixiashan deposit vary from 0.704816 to 0.71405; a part is larger than the 87Sr/86Sr ratios (0.708329~0.709685) for limestone of the Huanglong strata, which is the surrounding rock of the orebodies, whereas the other part is less than 87Sr/86Sr ratios for limestone of the Huanglong strata. A comparison of the strontium isotopic compositions of different sources reveals that the strontium from the Qixiashan deposit has the characteristics of the mixed sources, i.e., the strontium of Proterozoic basement strata and the mantle source; the change of 87Sr/86Sr ratios in the surrounding rock alteration should be mainly caused by the ore-forming fluid, and the change of 87Sr/86Sr ratios in the process of wall rock alteration should be mainly caused by the ore-forming fluid. A comprehensive analysis of regional metallogenic geological characteristics shows that the ore-forming fluid in the Qixiashan deposit might have come from the granite hydrothermal period, and by the influence of thermal power, the ore-forming fluid flowed through the Proterozoic basement strata, forming the ore-forming fluid with mixed material sources. The mineralization process of the Qixiashan deposit was mainly caused by the fluid-rock reaction between the ore-forming fluid and the surrounding rock.

       

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