摘要
黄铁矿是金矿床中重要的载金矿物,其地球化学特征不仅在矿床成因中具有重要的指示作用,也是重要的找矿信息。豫西九仗沟金矿床作为熊耳山金矿集区典型的构造蚀变岩型金矿床,是探讨黄铁矿对金矿床成因指示及找矿标志的理想矿床。通过开展九仗沟金矿床构造蚀变带调查,采集+260 m至-20 m垂深280 m的构造蚀变岩样品8件,对蚀变岩中黄铁矿进行矿物电子探针及激光剥蚀等离子体质谱分析,探讨不同蚀变带黄铁矿的元素含量特征及变化规律,以期获得黄铁矿对矿床成因及深部找矿的指示意义。研究结果表明,九仗沟金矿床+260 m中段至-20 m中段区间可划分为4个蚀变带,蚀变岩中黄铁矿均为成矿期黄铁矿,黄铁矿Fe、S元素含量显示其主要为硫亏型;微量元素聚类分析显示;Au与Cu、As、Sb、Zn、Ag、Te、Se、Pb为一组,属于中—低温元素组合;Co/Ni比值为1~10,Co-Ni-As图解显示黄铁矿为岩浆热液成因;黄铁矿中Au与Cu、As、Sb、Zn、Ag、Te、Pb呈正相关性,在第1—3蚀变带其含量同步逐渐降低,而在第4蚀变带则出现跳跃上升,第4蚀变带与第1—3蚀变带为不同期次热液成矿活动的产物。根据第1—3蚀变带的垂向延伸情况,推测第4蚀变带延深可达-60 m标高,深部至少还可以勘探一个中段(40 m),具有良好的找矿前景。黄铁矿中Au、Cu、As、Sb、Zn、Ag、Te、Se和Pb等元素含量及Au/As、Au/Ag、Co/Ni比值对垂向蚀变分带具有重要的指示作用,黄铁矿的微量元素标志是金矿床深部找矿靶区的重要信息。
[Objective]Pyrite is a common auriferous mineral in gold deposits.Its mineral geochemistry not only plays a significant role in elucidating ore genesis,but also provides important information for the exploration of deposits.The Jiuzhanggou gold deposit in western Henan Province is a gold deposit typical of tectonically altered rocks in the Xiong'ershan gold ore cluster,and it is an ideal deposit to study the genetic indications and prospecting signs of pyrite in gold deposits.[Methods]In this study,the tectonically altered zones of the Jiuzhanggou gold deposit were investigated,and 8 samples of tectonically altered rocks were collected over a vertical depth of 280 m,from+260 m to-20 m.Electron microprobe and laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS)analyses of pyrite from the altered rocks were carried out,and the characteristics and variations of the element contents in pyrite of differently altered zones were obtained,revealing the indications of pyrite for ore genesis and prospection at greater depth.[Results]The interval between the+260 m and-20 m levels of the Jiuzhanggou gold deposit can be divided into four altered zones.Microscopic observation of the altered rocks shows that pyrite was formed during the metallogenic period.Given its Fe and S contents,most of the pyrite is sulfur-depleted.Cluster analysis shows that Au,Cu,As,Sb,Zn,Ag,Te,Se and Pb in pyrite belong to a group of hypothermal-mesothermal elements.[Conclusion]The Co/Ni ratio(1~10)and the Co-Ni-As diagram indicate a magmatic hydrothermal origin of pyrite.The Au in pyrite is positively correlated with Cu,As,Sb,Zn,Ag,Te,and Pb.The contents of these elements gradually decrease in the 1st~3 rd altered zones,but increase in the 4th zone.It is speculated that the 1st~3 rd altered zones are the product of the same hydrothermal mineralization activity,while the 4th altered zone is the product of another hydrothermal mineralization activity.According to the vertical extent of the 1st~3 rd altered zones,it is speculated that the 4th altered zone may reach-60 meters.At least one level(40 m)can be explored at depth,which has a good prospecting potential.[Significance]The contents of Au,Cu,As,Sb,Zn,Ag,Te,Se,and Pb and the ratios of Au/As,Au/Ag,and Co/Ni in pyrite reflect the vertical mineralization zoning.These trace elements in pyrite are essential markers for prospecting targets in the deeper parts of gold deposits.
作者
司建涛
白德胜
赵志强
梁贞
阳静楠
刘建平
丁涛
Osama Ahmad
SI Jiantao;BAI Desheng;ZHAO Zhiqiang;LIANG Zhen;YANG Jingnan;LIU Jianping;DING Tao;Ahmad Osama(Henan No.2 Institute of Geology and Mineral Resources Survey Co.,Ltd.,Zhengzhou 450001,Henan,China;Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Central South University),Ministry of Education,Changsha 410083,Hunan,China)
出处
《地质力学学报》
北大核心
2025年第1期61-79,共19页
Journal of Geomechanics
基金
国家自然科学基金项目(41872091)。
关键词
黄铁矿
微量元素
找矿预测
九仗沟金矿床
豫西
pyrite
trace elements
metallogenetic prediction
Jiuzhanggou gold deposit
western Henan
