小秦岭金矿田杨砦峪金矿深部矿脉碳-氢-氧同位素特征及其对成矿流体来源的制约  

C-H-O isotopic characteristics of deep veins of Yangzhaiyu gold deposit in Xiaoqinling gold ore field and its constraint on the source of ore-forming fluid

作　　者：王鹏飞 冯帆 陈书印 杨生强 薛志强 丁毅 张苏坤 黄昊 WANG Pengfei;FENG Fan;CHEN Shuyin;YANG Shengqiang;XUE Zhiqiang;DING Yi;ZHANG Sukun;HUANG Hao(The First Geological Survey Institute of Mineral Resources,Henan Bureau of Geo-Exploration and Mineral Development,Luoyang 471023,Henan,China;Key Laboratory of Gold and Silver Polymetallic Ore-forming Series and Deep Prediction of Henan,Luoyang 471023,Henan,China;The Second Geological Exploration Institute,Henan Bureau of Geo-Exploration&Mineral Development,Zhengzhou 450018,Henan,China)

机构地区：[1]河南省地质矿产勘查开发局第一地质矿产调查院,河南洛阳471023 [2]河南省金银多金属成矿系列与深部预测重点实验室,河南洛阳471023 [3]河南省地质矿产勘查开发局第二地质勘查院,河南郑州461000

出　　处：《矿产与地质》2022年第1期120-128,共9页Mineral Resources and Geology

基　　金：河南省财政项目“河南省灵宝市小秦岭金矿田成矿规律及深部找矿预测研究”(编号:〔2018〕122号);“河南省灵宝市小秦岭金矿田南中矿带深部探测”(编号:〔2020〕18号)"小秦岭3500m深钻岩心红外光谱特征及蚀变分带研究"(豫地矿青科创〔2021〕1号)共同资助。

摘　　要：杨砦峪金矿床位于华北克拉通南缘,是小秦岭金矿田大型石英脉型矿床之一,关于区内金矿床成矿流体及成矿物质来源尚存争议。在总结矿床地质特征的基础上,对杨砦峪金矿S60深部矿脉进行碳-氢-氧(C-H-O)同位素特征研究,以探究成矿流体来源和成矿机制。H-O同位素测试结果表明,其δ^(18)O_(quartz)值为9.8‰~11.5‰,平均值为10.71‰,δD_(H2O)值为-56.1‰~-86.5‰,平均值为-68.02‰,与变质水和岩浆水接近。C-O同位素分析数据显示δ^(13)C_(CO2(PDB))值为8.90‰~-1.80‰,平均值为-4.20‰,δ^(18)O_(quartz)值为-2.03‰~13.61‰,平均值为8.38‰,表明成矿热液中的碳可能来自深部幔源;前人流体包裹体结果表明,成矿流体与高盐度、富含子晶的变质流体截然不同,而与燕山期花岗岩岩浆期后低盐富CO_(2)、H_(2)O的流体十分相似。这些特征表明,小秦岭金矿成矿流体主要来源于深部幔源流体而非变质热液,成矿机制主要是华北克拉通破坏、减薄,成矿物质被带出成矿,并非造山作用成矿,矿床成因类型属于克拉通破坏型金矿。The Yangzhaiyu gold deposit is located on the southern margin of the North China Craton.It is one of the large-scale quartz vein-type deposits in the Xiaoqinling gold field.There are still controversies about the ore-forming fluids and ore-forming material sources of the gold deposits in the area.On the basis of the summary of the geological characteristics of the deposit,the carbon-hydrogen-oxygen(C-H-O)isotope characteristics of the deep veins of S60 in Yangzhaiyu gold deposit are studied to explore the source of ore-forming fluids and metallogenic mechanism.The H-O isotope test results show that δ^(18)O_(quartz) value is 9.8‰-11.5‰,the average value is 10.71‰,δD_(H2O) value is-56.1‰-86.5‰,and the average value is-68.02‰,which is close to metamorphic water and magmatic water.C-O isotope analysis data show that δ^(13)C_(CO2(PDB))value is-8.90‰-1.80‰,the average is-4.20‰,δ^(18)O_(quartz) value is-2.03‰-13.61‰,and the average is 8.38‰,indicating that the carbon in the ore-forming hydrothermal fluid may be derived from a deep mantle source.The previous fluid inclusion results show that the ore-forming fluid is completely different from the metamorphic fluid with high salinity and rich in daughter crystals,and is very similar to the low-salt CO_(2)and H_(2)O-rich fluid after the Yanshanian granite magma stage.These characteristics indicate that the ore-forming fluids of the Xiaoqinling gold deposit are mainly derived from deep mantle-derived fluid rather than metamorphic hydrothermal fluid.The ore-forming mechanism is mainly the destruction and thinning of the North China Craton.The genetic type of the deposit belongs to the craton-destructive gold deposit.

关 键 词：杨砦峪金矿 碳-氢-氧同位素 成矿流体 成矿机制 克拉通破坏型金矿 小秦岭 

分 类 号：P618.51[天文地球—矿床学]