投稿时间：2018-10-08
修订日期：2019-01-31
网络发布日期：2019-04-30
中文摘要:陈家坝铜铅锌多金属矿床为近年来在陕西勉（县）-略（阳）-宁（强）铜金镍矿化集中区新发现的铜铅锌多金属矿床。为了查明陈家坝矿床成矿物质来源，笔者开展了系统的C、H、O、S和Sr同位素地球化学研究。结果表明，陈家坝矿区的围岩的δ13CPDB值范围-0.93‰~1.44‰，平均值为0.35‰，δ18OV-SMOW值范围14.14‰~27.49‰，平均22.1‰，为沉积成因海相碳酸盐岩。脉石矿物白云石的δ13CPDB范围在-0.53‰~-0.89‰，δ18OV-SMOW值范围12.12‰~13.23‰，指示成矿流体中的CO2主要来自岩浆水，少量CO2来源于围岩海相碳酸盐岩的溶解作用。成矿流体中δD值范围-91‰~-72‰，δ18OH2O值范围6.7‰~9.4‰，在δD-δ18OH2O图解中主要落于原生岩浆水范围内，成矿流体以岩浆流体为主。成矿流体与围岩的水-岩反应是导致该区铜铅锌矿床中白云石和黄铜矿、闪锌矿和方铅矿矿物沉淀结晶的主要机制。矿石金属硫化物δ34S值范围4.88‰~8.90‰，平均值为7.37‰，介于岩浆硫与海水硫之间，且与矿集区内典型的徐家沟铜矿床矿石矿物δ34S变化区间重叠，表明硫主要来自于岩浆硫，部分硫来自海水硫酸盐。矿石中黄铁矿的初始锶同位素比值87Sr/86Sr比值为0.72，高于赋矿围岩锶同位素比值，接近大陆地壳的87Sr/86Sr比值（0.719），指示了成矿流体流经了雪花太坪组地层，并与其中具有高87Sr/86Sr比值的白云岩进行水岩反应及同位素交换。
Abstract:The Chenjiaba Cu-Pb-Zn polymetallic deposit in Shaanxi Province, located in Mian(xian)-Lue(yang)-Ning (qiang) Cu-Au-Ni ore concentration area, is a newly discovered deposit. In this paper, C, H, O, S and Sr isotopic geochemistry was systematically studied in order to understand comprehensively the source of ore-forming mate-rials. The analytical results show that 13CPDB and 18OV-SMOW values of surrounding rocks are between -0.93‰ and 1.44‰ and 14.14‰ and 27.49‰, respectively, suggesting that the surrounding rocks were derived from marine carbonate dissolution. the δ13CPDB values of gangue dolomite samples are in the range of -0.53‰~-0.89‰, and the 18OV-SMOW values in the range of 12.12‰~13.23‰. In the Chenjiaba Cu-Pb-Zn polymetallic deposit, the CO2 in the ore-forming fluid was mainly derived from magmatic water, with a small amount from marine carbonate dissolution. The δDV-SMOW of the quartz fluid inclusions is between -91‰ and -72‰, the δ18OH2O is between 6.7‰ and 9.4‰, and the δD-δ18OH2O diagram shows that the main source of ore-forming fluid was magmatic water. Water-rock reaction between ore-forming fluid and surrounding rock was the main mechanism resulting in the precipitation and crystallization of dolomite, sphalerite, chalcopyrite and galena in Chenjiaba Cu-Pb-Zn polymetallic deposit, Shaanxi. Sulfur isotopic compositions (δ34S from 4.88‰ to 8.90‰, 7.37 ‰ on average) are both magmatic sulfur and seawater sulfur, consistent with the data of the typical Xujiagou Cu deposit in this area. The results indicate that sulfur sources were mainly sourced from magmatic sulfur with the addition of small amounts of seawater sulfur. The 87Sr/86Sr ratio of pyrite in the ore is 0.7187, higher than 87Sr/86Sr ratio (0.7083) of surrounding rock and similar to the ratio of continental crust (0.719), suggesting that ore-forming fluid probably migrated through the formation of Xuehuataiping Formation, and experienced water-rock reaction and isotope exchange between the ore fluid and the dolomite which had high 87Sr/86Sr values.
keywords:geochemistry C,H,O,S and Sr isotopes metal sources Chenjiaba Cu-Pb-Zn polymetallic deposit Shaanxi
文章编号：
中图分类号：P618.51
文献标志码：
基金项目:国家自然科学基金青年科学基金项目（编号：41603040）、西北有色地质矿业集团有限公司博士后科研项目、中国地质调查局项目（编号：1212011220869）联合资助
引用文本：
丁坤,王瑞廷,秦西社,梁婷,杨秀清,栾燕,郑崔勇,樊新祥.2019.陕西陈家坝铜铅锌多金属矿床C、H、O、S、Sr同位素地球化学示踪[J].矿床地质,38(2):355~366DING Kun,WANG RuiTing,QIN XiShe,LIANG Ting,YANG XiuQing,LUAN Yan,ZHENG CuiYong,FAN XinXiang.2019.C, H, O, S, Sr isotopic geochemistry of Chenjiaba Cu-Pb-Zn polymetallic deposit, Shaanxi Province[J].Mineral Deposits38(2):355~366
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