湘中矿集区钨与锑-金成因联系探讨:来自曹家坝钨矿床和龙山锑金矿床Sr-Nd-H-O同位素的制约  

Discussion of the genetic relations between W and Sb-Au mineralization of Xiangzhong ore district:Constraints from Sr-Nd-H-O isotopic compositions of the Caojiaba W and Longshan Sb-Au deposits

作　　者：张志远 谢桂青[2,3] 袁亮 ZHANG ZhiYuan;XIE GuiQing;YUAN Liang(Hebei Key Laboratory of Strategic Critical Mineral Resources,Hebei GEO University,Shijiazhuang 050031,China;School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China;MNR Key Laboratory for Exploration Theory&Technology of Critical Mineral Resources,Beijing 100083,China;Hunan Xinlong Mining Co.Ltd.,Shaoyang 422927,China)

机构地区：[1]河北地质大学,河北省战略性关键矿产资源重点实验室,石家庄050031 [2]中国地质大学地球科学与资源学院,北京100083 [3]自然资源部战略性金属矿产找矿理论与技术重点实验室,北京100083 [4]湖南新龙矿业有限责任公司,邵阳422927

出　　处：《岩石学报》2023年第6期1847-1860,共14页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(41925011、42002094)资助。

摘　　要：湘中是全球最大的锑金矿集区,近年来又陆续探明了一批钨矿床,但这些钨矿和锑金矿之间的关系目前尚不明确。曹家坝钨矿床是目前该矿集区内规模最大的钨矿床(19.03Mt@0.37%WO3),矿体与矽卡岩密切共生,成矿作用划分为矽卡岩阶段、退化蚀变阶段和石英-白钨矿-硫化物阶段。不同阶段白钨矿δ18OV-SMOW变化范围为6.0‰-7.9‰,δDV-SMOW变化范围为-79.1‰--68.9‰,对应的δ18OH2O变化范围为3.3‰-5.2‰。白钨矿(87Sr/86Sr)t变化范围为0.72215-0.73049,εNd(t)变化范围为-12.8--10.6。龙山锑金矿床是矿集区内发育的大型脉状锑金矿床(4.2Mt@3.4%Sb和3.7g/t Au),矿体赋存在震旦系江口组板岩中,发育两个世代的白钨矿与辉锑矿共生。白钨矿δ18OV-SMOW变化范围为5.4‰-9.0‰,δDV-SMOW变化范围为-72.9‰--60.2‰,对应的δ18OH2O变化范围为3.1‰-6.7‰。Sr-Nd-H-O多元同位素特征显示,曹家坝钨矿床的成矿物质和成矿流体以岩浆来源为主,龙山锑金矿床有岩浆流体参与成矿,两者均有少量板溪群基底地层和大气降水的加入。综合本次及前人研究成果,曹家坝钨矿床和龙山锑金矿床具有成因联系,二者均是湘中矿集区晚三叠世岩浆热液W-Sb-Au成矿系统的重要组成部分。The Xiangzhong has been the largest Sb-Au ore district in the world so far.In recent years,a number of W deposits have been discovered in this area,however,the relationship between the W and Sb-Au mineralization is still unclear.The Caojiaba deposit is the largest W deposit in the ore district up to now(19.03Mt@0.37%WO 3),whose ore bodies are closely related to skarn,i.e.,its mineralization is characterized by an early prograde skarn overprinted by a retrograde assemblage,and then by quartz-scheelite-sulfide veins.Geochemically,theδ18 O V-SMOW andδD V-SMOW of scheelites formed at different stages of the deposit range from 6.0‰to 7.9‰and from-79.1‰to-68.9‰,respectively,with correspondingδ18 O H 2O values varying from 3.3‰to 5.2‰;while the(87 Sr/86 Sr)t andεNd(t)of the scheelites range from 0.72215 to 0.73049,from-12.8 to-10.6,respectively.The Longshan deposit is a large lode Sb-Au deposit in the ore district(4.2Mt@3.4%Sb and 3.7g/t Au).The ore body is hosted within Sinian Jiangkou Formation slate,and two generations of scheelites are associated with stibnite.Theδ18 O V-SMOW andδD V-SMOW of scheelite range from 5.4‰to 9.0‰and from-72.9‰to-60.2‰,respectively,with correspondingδ18 O H 2O values ranging from 3.1‰to 6.7‰.The Sr-Nd-H-O isotopic compositions show that ore-forming material and fluid of the Caojiaba tungsten deposit were mainly derived from the magmatic-hydrothermal system.The magmatic fluid was involved in the mineralization of the Longshan Sb-Au deposit,and minor Banxi Group basement strata and meteoric water were involved in the ore-forming process of the Caojiaba and Longshan deposits.Based on the results of this study and previous work,the Caojiaba W deposit and the Longshan Sb-Au deposit are genetically related to each other,i.e.,both of them are important components of the Late Triassic magmatic hydrothermal W-Sb-Au metallogenic system in the Xiangzhong ore district.

关 键 词：白钨矿 Sr-Nd-H-O同位素 曹家坝钨矿床 龙山锑金矿床 湘中矿集区 

分 类 号：P618.2[天文地球—矿床学]