四川乌斯河铅锌矿床闪锌矿微量元素特征及其指示意义  

CHARACTERISTICS OF TRACE ELEMENTS IN SPHALERITE AND ITS IMPLICATION FOR WUSIHE LEAD-ZINC DEPOSIT,SICHUAN PROVINCE

作　　者：赵文皓 陈翠华[1] 康许浩 杨玉龙 孙世强 马天祺 赖翔 辜鹰 陈宵杰 ZHAO Wenhao;CHEN Cuihua;KANG Xuhao;YANG Yuong;SUN Shiqiang;MA Tianqi;LAI Xiang;GU Ying;CHEN Xiaojie(College of Earth and Planetary Sciences,Chengdu University of Technology,Chengdu,Sichuan 610059,China)

机构地区：[1]成都理工大学地球与行星科学学院,四川成都610059

出　　处：《矿物岩石》2024年第2期62-73,共12页Mineralogy and Petrology

基　　金：省级自然科学基金(批准号:2023NSFSCO274)。

摘　　要：四川乌斯河铅锌矿床是川滇黔地区的大型矿床之一,近年来以其富含稀散元素Ge而备受关注,学者们在此做了大量的研究,但对其成因类型及Ge元素在矿床中的分布仍存在争议。本次研究运用显微镜下观察及LA-ICP-MS分析等测试手段,对乌斯河矿床按照矿体的不同部位采集两阶段闪锌矿共计12块样品,对其微量元素组成、结构特征等进行了测试分析,研究结果表明,该矿床中不同阶段的闪锌矿都具有相对富集Cd,Ga,Ge元素,贫Se、In的特征,其中Ⅰ阶段闪锌矿中Ge含量平均值为186×10^(-6),Ⅱ阶段闪锌矿中Ge含量平均值为56.4×10^(-6),两阶段的闪锌矿中Ge含量均大于5.00×10^(-6),Ⅰ阶段闪锌矿中的Ge含量高于Ⅱ阶段。此外,由Ⅰ阶段闪锌矿Zn/Fe的比值介于32.9~276.0,Ⅱ阶段闪锌矿Zn/Fe的比值介于126~3183得知,两阶段的闪锌矿成矿时的温度都属中一低温,且Ⅰ阶段闪锌矿的温度略高于Ⅱ阶段,得出在乌斯河矿床中Ge更易在温度较高的闪锌矿中富集。结合乌斯河矿床基础地质特征、微量元素组成特征、前人研究成果和本次研究内容可知,其与SEDEX,矽卡岩型以及岩浆热液型的矿床在微量元素特征、大地构造环境、矿体形态、矿石组构、矿物组合、围岩蚀变等方面存在明显区别,而与川滇黔地区MVT铅锌矿床(如会泽等铅锌矿床)基本一致。因此,认为乌斯河铅锌矿床属于MVT铅锌矿床。The Wusihe lead-zinc deposit in Sichuan Province stands out among the large deposits in the Si-chuan-Yunnan-Guizhou area due to its significant germanium(Ge)content.While extensive research has been conducted on this deposit,there are lingering controversies regarding its genetic type and the distri-bution of Ge elements within the deposit.To address this,twelve sphalerite samples representing two sta-ges were collected from various parts of the ore body in the Wusihe Deposit.Microscope observation and LA-ICP-MS analysis were utilized to examine the composition and structural characteristics of trace ele-ments in the ore samples.The results reveal that sphalerite from different stages of the deposit exhibits relatively high levels of cadmium(Cd),gallium(Ga),and Ge elements,while being deficient in selenium(Se)and indium(In).The average Ge content in stage I sphalerite is 186×10^(-6),whereas it is 56.4×10^(-6) in stage Ⅱ sphalerite.Notably,both stages exhibit Ge contents exceeding 5.00×10^(-6),with stage Ⅰ sphalerite demonstrating higher Ge content compared to stage Ⅱ.Additionally,the Zn/Fe ratio of stage Ⅰ sphalerite ranges from 32.9 to 276,while stage Ⅱ sphalerite shows a ratio between 126 and 3183,indi-cating higher temperatures for stage Ⅰ sphalerite than stage Ⅱ.In the Wusihe deposit,Ge enrichment is notably associated with sphalerite formed at higher temperatures.The research findings suggest that the Wusihe deposit diverges significantly from SEDEX,skarn,and magmatic hydrothermal deposits in terms of trace element characteristics,tectonic environment,ore morphology,ore fabric,mineral association,and surrounding rock alteration.Instead,it closely aligns with MVT(Mississippi Valley Type)lead-zinc deposits,such as the Huize lead-zinc deposits in the Sichuan-Yunnan-Guizhou area.Consequently,the Wusihe lead-zinc deposit is categorized as an MVT lead-zinc deposit.

关 键 词：乌斯河铅锌矿床 闪锌矿 微量元素特征 MVT铅锌矿床 LA-ICP-MS 

分 类 号：P595[天文地球—地球化学] P611[天文地球—地质学]