南秦岭镇安棋盘沟钨矿床^(40)Ar-^(39)Ar年代学及其对印支末期成矿的指示  

Phlogopite^(40)Ar-^(39)Ar Dating of the Qipangou Tungsten Deposit in Western Zhen’an,South Qinling Mountains and its Significance of Late Indosinian Ore Mineralization

作　　者：晁会霞[1,2] 崔文玮 杨兴科[1,2] 王冉[1,2] 韩珂 杨宁 王仪卓 CHAO Huixia;CUI Wenwei;YANG Xingke;WANG Ran;HAN Ke;YANG Ning;WANG Yizhuo(School of Earth Science and Resources,Chang’an University,Xi’an 710054,Shaanxi,China;MLR Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits,Xi’an 710054,Shaanxi,China;Xi’an Research Institute Co.Ltd.,China Coal Technology and Engineering Group Corp.,Xi’an 710077,Shaanxi,China)

机构地区：[1]长安大学地球科学与资源学院,陕西西安710054 [2]长安大学西部矿产资源与地质工程教育部重点实验室,陕西西安710054 [3]中煤科工集团西安研究院有限公司,陕西西安710077

出　　处：《大地构造与成矿学》2023年第3期570-579,共10页Geotectonica et Metallogenia

基　　金：陕西省自然科学基础研究计划项目(2023-JC-YB-276);陕西省公益性地质工作项目(0617-17111FY1808);中央高校基本科研专项资金项目(300102280401)联合资助。

摘　　要：近年来,南秦岭镇安西部地区发现了棋盘沟、核桃坪、东阳等大中型钨多金属矿床。其中棋盘沟大型钨矿床以石英脉型为主,深部可见矽卡岩型矿化,前人仅对其中的石英脉型钨矿进行了年龄测试,深部的矽卡岩型钨矿尚未开展年代学研究工作。本文以棋盘沟钨矿床为研究对象,选取两类矿石中与白钨矿、辉钼矿密切共生的金云母进行^(39)Ar-^(40)Ar同位素测年。结果显示,矽卡岩型矿石中金云母坪年龄为190.1±0.6 Ma(MSWD=1.28),石英脉型矿石中金云母坪年龄为188.6±0.6 Ma(MSWD=1.42),均为早侏罗世成矿,且石英脉型钨矿成矿时间略晚于矽卡岩型钨矿。该成矿期处于南秦岭成矿带陆内碰撞造山向伸展转变的转折期,代表着一期重要的、尚未被广泛关注的印支末期的岩浆热液钨钼成矿事件,应在今后的找矿工作中予以重视。The recently discovered Qipangou large-scale tungsten deposit is located within the Southern Qinling Orogenic belt,Northwest China.The deposit is hosted within a NWW fault belt,and is characterized by subsurface quartz vein type mineralization and deep skarn-type mineralization.Both the pluton and exo-contact zone contain W polymetallic mineralization,and the economic orebodies mainly occur in the quartz veins and skarns.The Hetaoping and Dongyang tungsten polymetallic deposits also in the NWW fault belts,and both deposits are associated with granites and host quartz vein type and skarn type ores.^(40)Ar-^(39)Ar dating of phlogopite closely associated with scheelite and molybdenite in the two kinds of ores from the Qipangou tungsten deposit yielded plateau ages of 188.6±0.6 Ma(MSWD=1.42)(quartz vein type)and 190.1±0.6 Ma(MSWD=1.28)(skarn-type),respectively.Therefore,the Qipangou tungsten deposit was formed in the early Jurassic,and the quartz vein type ores was formed somewhat later than the skarn type ores.The magma-hydrothermal event in the Qipangou tungsten deposit clearly took place after the Triassic peak magmatism.This phenomenon most likely indicates a significant ore mineralization related to the most recent magma-hydrothermal event triggered by the collapse of the orogenic belt following the collision between the North China Craton and the South China tectonic plate along the Qinling Mountain during the Indosinian period.The potentiality of the W polymetallic mineralization in the belt should be emphasized in future exploration and metallogenic study of the Qinling metallogenic province.

关 键 词：^(40)Ar-^(39)Ar定年 金云母 白钨矿 印支末期 南秦岭 

分 类 号：P618.6[天文地球—矿床学]