南秦岭香沟金钨矿白钨矿原位微区分析及方解石Sm-Nd同位素定年:对钨成矿过程的限定  

Scheelite geochemical signature and calcite Sm-Nd dating of the Xianggou Au-W deposit in south Qinling orogen,central China:Constraints on the ore-forming process

作　　者：薛玉山 刘新伟 胡西顺 寸小妮 杨海涛 XUE Yushan;LIU Xinwei;HU Xishun;CUN Xiaoni;YANG Haitao(Xi'an NorthwestResearch Institute ofNonferrousMetalsCo.,Ltd.,Xi'an 710054,Shaanxi,China)

机构地区：[1]西安西北有色地质研究院有限公司,陕西西安710054

出　　处：《中国地质》2021年第6期1818-1837,共20页Geology in China

基　　金：西安西北有色地质研究院有限公司科研基金项目(2017J02)资助。

摘　　要：陕西省山阳县香沟钨矿是近年来南秦岭地质勘查新发现的钨矿化地段之一。本文开展了白钨矿电子探针、LA-ICP-Ms和共生方解石的Sm-Nd同位素测年,研究结果显示:香沟白钨矿成矿过程至少可划分为两个阶段,由早阶段韵律环带白钨矿至晚阶段集合体状白钨矿,白钨矿经历了多次迁移;白钨矿具有高F、含微量Au元素的特征,稀土总量较高(ΣREE+Y含量介于5.44×10^(-6)~382.67×10^(-6,)平均为95.48×10^(-6)),其稀土配分型式为无MREE富集的平坦型,与Ghaderi等人划分的白钨矿Ⅱ型稀土配分型式总体类似,负铕异常,利用白钨矿La-Ce-Y三角图解,结合地质事实,判断香沟钨矿属于石英脉型钨矿;结合共生方解石Sm-Nd同位素年龄195 Ma,认为南秦岭香沟钨矿是印支末期深部隐伏岩浆-热液活动的结果。The Xianggou scheelite deposit,discovered in the Wangjiaping-Longtougou-Xiajiadian gold metallgenic belt in recent years,is another new geology survey progress in south Qinling related to W mineralization.The composition of scheelite was analyzed by LA-ICP-MS,together with Sm-Nd isotope dating of symbiotic calcite,to clarify the origin of Xianggou scheelite.The results show that scheelite exists in three generations,from the early rhythmic zonal scheelite to the late aggregate one,indicating that the scheelite undergone multiple migrations.The scheelites have high F content with low Au content.The total amount of rare earths is high,ranging from 5.44×10^(-6 )to 382.67×10^(-6),with an average of 95.48×10^(-6).The REE pattern is flat without MREE enrichment,with negative Eu anomaly,similar to the typeⅡREE type classified by Ghaderi et al.(1999).All these data support that the W mineralization in the Xianggou area might be related to W-bearing quartz vein with genetic links to magmatic hydrothermal activities.The Sm-Nd isotope dating result of the symbiotic calcite(195 Ma)indicates that the deposit was formed in the late Indosinian.

关 键 词：金钨矿化 白钨矿 SM-ND同位素定年 香沟金矿 矿产勘查工程 陕西省 

分 类 号：P618.67[天文地球—矿床学] P597[天文地球—地质学]