扬子板块北缘马元铅锌矿床稀土元素地球化学研究  

REE geochemistry of Mayuan Pb-Zn deposit on northern margin of Yangtze Plate

作　　者：刘淑文[1] 石顺 李荣西[1] 高云宝[2] 刘玲芳 段立志[1] 陈宝贇 张少妮[1] 

机构地区：[1]长安大学地球科学与国土资源学院,陕西西安710054 [2]西安地质矿产研究所,陕西西安710054 [3]西北有色地质勘查局物化探总队,陕西西安710068

出　　处：《矿床地质》2013年第5期979-988,共10页Mineral Deposits

基　　金：国家科技支撑计划项目(2006BAB01A01);国家自然科学基金项目(基金号:41102050);中国地质调查局项目1212011121117)联合资助

摘　　要：马元铅锌矿床是近年来在扬子板块北缘铅锌找矿的新突破。文章通过对马元铅锌矿床原生矿体中不同脉石矿物及矿区出露地层中稀土元素地球化学特征的研究,探讨了其成矿物质来源。马元矿区热液脉石矿物及出露的沉积地层稀土元素北美页岩标准化配分曲线总体呈比较平坦的特点,而且在Y-∑REE图解中呈线性分布,表明成矿物质主要来源于沉积地层。晚期方解石较早期热液白云石具有轻稀土元素总量高且相对富集的特点,表明二者是不同来源流体演化的结果。早期热液白云石在稀土元素总量(∑REE)、轻、重稀土元素比值LREE/HREE以及在Y-∑REE图解上的分布等方面与灯影组白云岩比较接近,说明早期热液白云石主要来源于灯影组白云岩的溶解;而晚期方解石稀土元素总量明显高于灯影组白云岩而低于基底及古生代沉积碎屑岩系,晚期流体可能流经了具有高稀土元素总量的基底及沉积盆地中的碎屑岩系。矿区热液脉石矿物北美页岩标准化稀土元素配分曲线均显示出有较明显的Eu异常,表明成矿流体具有相对较高温(>200℃)和还原的环境。The newly-discovered Mayuan Pb-Zn deposit occurs in bedded and stratoid forms and lies in a structural zone of dolomite brecciasin the Sinian Dengying Formation on the northern margin of Yangtze craton.REE geochemistry of hydrothermal gangue minerals and sedimentary strata in the Mayuan Pb-Zn deposit was analyzed in this paper with the purpose of understanding comprehensively the source of ore materials.The North America shales-normalized REE patterns of hydrothermal gangue minerals and sedimentary strata are almost flat and assume linear distribution in Y-∑REE diagram,suggesting that ore-forming materials originated from sedimentary formations.The higher？REE and LREE-enriched REE patterns of the late-stage calcites relative to earlystage hydrothermal dolostone show that they were derived from fluids of different origins.The early-stage hydrothermal dolostone is similar to Sinian dolostone in？REE,REE patterns and the positions in Y-∑REE diagram,indicating that Dengying dolostone might have served as the main material source.The late-stage calcites have higher？REE values than Sinian dolomite and lower？REE values than basement and Paleozoic sedimentary strata,implying that the late-stage ore-forming fluid probably migrated through the basement and Paleozoic sedimentary strata.The positiveδEuNanomalies in hydrothermal gangue minerals show that the deposit was formed in a relatively high temperature（〉200℃）and reductive environment.

关 键 词：地球化学 REE 成矿物质来源 马元铅锌矿 

分 类 号：P618.42[天文地球—矿床学] P618.43[天文地球—地质学]