扬子地块西南缘乌斯河富锗闪锌矿矿物标型特征与锗的替代机制  

Mineral Typomorphic Characteristics and Deposit Genesis of Germanium-Enriched Sphalerite from Wusihe in the Southwestern Margin of the Yangtze Block

作　　者：孙世强 陈翠华[1] 赵文皓 赖翔 马天祺 张海军 乔梦怡 宋志娇[1] 陈宵杰 辜鹰 SUN Shiqiang;CHEN Cuihua;ZHAO Wenhao;LAI Xiang;MA Tianqi;ZHANG Haijun;QIAO Mengyi;SONG Zhijiao;CHEN Xiaojie;GU Ying(School of Earth and Planetary Sciences,Chengdu University of Technology,Chengdu 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：《岩矿测试》2025年第2期214-229,共16页Rock and Mineral Analysis

基　　金：四川省科技厅自然科学基金项目“四川汉源乌斯河铅锌矿床闪锌矿中关键金属锗的富集机制及成因矿物学找矿标志”(2023NSFSC0274)。

摘　　要：锗(Ge)是中国优势战略性关键金属之一,扬子地块西南缘乌斯河铅锌矿床是川—滇—黔成矿带的一个重要富锗铅锌矿床,其矿床成因仍存在争议,矿床中闪锌矿的标型特征是否影响Ge的富集程度与替代方式亟待进行解析。为探讨富Ge闪锌矿的标型特征及Ge的替代机制,本文通过显微镜下观察、显微分光光度计、激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)等分析测试方法对其进行定量研究。结果表明该矿床热液期存在Ⅰ阶段颜色较深闪锌矿和Ⅱ阶段颜色较浅闪锌矿,视觉反射率均值分别为16.126%、16.187%,反射色主波段均值分别为474.179nm、474.164nm,反射色饱和度均值分别为0.048、0.043,Ge含量均值分别为244.33×10^(-6)、43.22×10^(-6)。通过对实验结果的总结认为,Ge以类质同象的形式存在于闪锌矿中,且更易在反射色饱和度高的闪锌矿中富集。Ge的替代方式与Cu、Ag有关,两阶段分别为Ge^(4+)+2Cu^(+)←→3Zn^(2+)、Ge^(4+)+2(Cu,Ag)^(+)←→3Zn^(2+)。富Ge闪锌矿的反射色颜色指数特征指示成矿温度上限为203.0~293.0℃,微量元素特征指示成矿温度下限为83.3~199.0℃,矿床成因类型为密西西比河谷型(MVT)铅锌矿床。The Wusihe lead-zinc deposit,situated at the southwestern margin of the Yangtze Block and a prominent Ge-enriched deposit within the Sichuan—Yunnan—Guizhou lead-zinc metallogenic belt,faces ongoing debates regarding its genesis.The influence of sphalerite typomorphic characteristics on Ge enrichment and substitution mechanisms within the deposit remains a crucial puzzle to unravel.To address this,the paper employs quantitative analyses using microscopic spectrophotometry and laser ablation-inductively coupled plasma-mass spectrometry(LA-ICP-MS).The results reveal the presence of two sphalerite stages during the hydrothermal period:a darker StageⅠand a lighter StageⅡ.Despite similar mean values for visual reflectance and the dominant wavelength of reflectance color,the mean reflectance color saturation differs(0.048 and 0.043,respectively),with corresponding average Ge contents of 244.33×10^(-6)μg/g and 43.22×10^(-6)μg/g,respectively.The experimental outcomes conclude that Ge exists in sphalerite as isomorphism and is more concentrated in sphalerite with higher reflectance color saturation.The ore-forming temperature is medium to low,classifying the deposit as a Mississippi Valley-type lead-zinc deposit.

关 键 词：富锗铅锌矿床 闪锌矿标形特征 替代机制 显微分光光度计 激光剥蚀电感耦合等离子体质谱 类质同象 密西西比河谷型铅锌矿床 

分 类 号：P578.23[天文地球—矿物学] P611[天文地球—地质学]