北山造山带双尖山—狼娃山地区金矿床硫化物硫同位素及微量元素对成矿机制的指示  

Sulfur isotopes and trace elements of sulfides in gold deposits in the Shuangjianshan-Langwashan area of the Beishan orogenic belt as indicators of metallogenic mechanism

作　　者：张晨晓 白荣龙 樊炳良 陈雪锋 虎金荣 樊立飞 张跃珂 ZHANG Chenxiao;BAI Ronglong;FAN Bingliang;CHEN Xuefeng;HU Jinrong;FAN Lifei;ZHANG Yueke(College of Resources and Environmental Engineering,Tianshui Normal University,Tianshui 741001,Gansu,China;Key Laboratory of Strategic Mineral Resources of the Upper Yellow River,Ministry of Natural Resources,Lanzhou 730000,Gansu,China;Zijin Mining Group Southwest Geological Exploration Co.,Ltd.,Chengdu 610057,Sichuan,China;Gansu Nonferrous Geological Survey Institute,Lanzhou 730000,Gansu,China)

机构地区：[1]天水师范学院资源与环境工程学院,甘肃天水741001 [2]自然资源部黄河上游战略性矿产资源重点实验室,甘肃兰州730000 [3]紫金矿业集团西南地质勘查有限公司,四川成都610057 [4]甘肃省有色地质调查院,甘肃兰州730000

出　　处：《地质通报》2025年第2期276-297,共22页Geological Bulletin of China

基　　金：甘肃省科技计划项目(重点研发计划)《北山造山带北部跃进山铜钨钼多金属矿床岩浆-热液演化与成矿耦合机制研究》(编号:23YFGA0021);甘肃省科技计划项目(自然科学基金)《北山造山带双尖山—狼娃山地区金矿床富集机理研究》(编号:22JR5RE199);自然资源部黄河上游战略性矿产资源重点实验室开放基金课题《北山造山带双尖山—红柳丘井地区岩浆-热液矿床中铜金钨富集机制研究》(编号:YSMRKF202208)。

摘　　要：【研究目的】双尖山—狼娃山地区位于中亚造山带中段南缘,北山造山带北部的明水岩浆弧地段,目前该地区矿床成因等信息尚不明确,厘清该地区金矿床硫化物中微量元素的赋存状态、流体性质、成矿机制,进而指导勘查实践。【研究方法】在野外地质调查和矿相学研究的基础上,对区域内双尖山、大红泉、狼娃山金矿床主成矿阶段的黄铁矿和黄铜矿开展LA-ICP-MS微量和稀土元素及硫同位素分析。【研究结果】结果表明,双尖山—狼娃山地区金矿床的金有可见金及不可见金2种赋存形式,不可见金主要以固溶体金(Au^(1+))的形式赋存于黄铁矿晶格中。Pb和Bi主要以辉铋矿或Bi以固溶体的形式存在于方铅矿包裹体中。大红泉和狼娃山矿床中Zn与Cd、Pb与Sb之间呈正相关关系,表明黄铁矿中存在闪锌矿、方铅矿等矿物包体。双尖山—狼娃山地区金矿床Nb/La、Th/La、Hf/Sm值多小于1,指示成矿流体中富含Cl^(-);Co、Ni的含量及比值指示成矿流体具有中低温、低盐度的特点;Cu/Au值指示成矿流体整体处于较还原的环境;Y/Ho、Zr/Hf、Nb/Ta值指示成矿过程存在多期次流体的叠加,双尖山金矿床成矿晚期流体可能与大气降水相混合。双尖山、大红泉和狼娃山矿床硫化物δ^(34)S均值分别为2.58‰、2.07‰和1.22‰,双尖山硫同位素值变化范围相较于大红泉、狼娃山金矿床偏大,显示岩浆硫与地层硫的混合特征,而大红泉和狼娃山金矿床δ^(34)S值均为极低的正值,显示出岩浆硫的特征。【结论】综合对比野外地质特征、微量元素及硫同位素组成,认为双尖山及狼娃山金矿床属低硫型浅成低温热液型金矿床,大红泉金矿床为造山型金矿床,区域成矿作用具有多期次性。[Objective]The Shuangjianshan-Langwashan area is situated in the southern margin of the central segment of the Central Asian Orogenic Belt,specifically within the Mingshui magmatic arc of the northern Beishan Orogenic Belt.Currently,critical information regarding the genesis of mineral deposits in this region remains unclear.This study aims to investigate the occurrence state of trace elements in sulfides,fluid characteristics,and metallogenic mechanisms of gold deposits in the Shuangjianshan-Langwashan area,with the ultimate objective of guiding exploration practices.[Methods]Based on field geological investigations and ore microscopy studies,LA-ICP-MS analyses of trace elements,rare-earth elements,and sulfur isotopes were performed on pyrite and chalcopyrite from the main metallogenic stages of the Shuangjianshan,Dahongquan,and Langwashan gold deposits in the region.[Results]The results show that gold in the Shuangjianshan-Langwashan area gold deposits exists in two forms:visible gold and invisible gold.Invisible gold is mainly hosted in the pyrite lattice in the form of solid-solution gold(Au^(1+)).Pb and Bi are mainly present in galena inclusions,either in the form of bismuthinite or as solid-solution Bi.In the Dahongquan and Langwashan deposits,the positive correlations between Zn and Cd,and between Pb and Sb indicate the presence of mineral inclusions such as sphalerite and galena in pyrite.The Nb/La,Th/La,and Hf/Sm values in the Shuangjianshan-Langwashan gold deposit are mostly less than 1,indicating that the ore-forming fluid is rich in Cl^(-).Likewise,the content and ratio of Co and Ni indicate that the ore-forming fluid has the characteristics of medium-low temperature and low salinity.Moreover,Cu/Au indicates that the overall ore-forming fluid is in a relatively reducing environment.And the Y/Ho,Zr/Hf,and Nb/Ta values indicate the presence of multiple stages of fluid superposition in the metallogenic process.In the late metallogenic stage of the Shuangjianshan gold deposit,the fluid may have mixed with

关 键 词：北山造山带 金矿 微量元素 硫同位素 矿床成因 

分 类 号：P618.51[天文地球—矿床学] P595[天文地球—地质学]