青海省牛苦头铅锌矿床成矿时代研究:来自成矿岩体年代学和黄铁矿Re-Os地球化学证据  

Mineralization Age and Ore forming-Source of Niukutou Pb-Zn Deposit,Qinghai:Evidence from Geochronology of Ore-forming Rock Bodies and Re-Os Geochemistry of Pyrite

作　　者：王新雨 王书来[1] 吴锦荣 王幻 祝新友[1] 王玉往[1] 张坤 刘明 杨星 蔡亚伟 WANG Xinyu;WANG Shulai;WU Jinrong;WANG Huan;ZHU Xinyou;WANG Yuwang;ZHANG Kun;LIU Ming;YANG Xing;CAI Yawei(Beijing Institute of Geology for Mineral Resources Co.,Ltd,Beijing 100012,China;The Qinghai Hongxin Mining Co.,Ltd,Golmud 816099,Qinghai,China)

机构地区：[1]北京矿产地质研究院有限责任公司,北京100012 [2]青海鸿鑫矿业有限公司,青海格尔木816099

出　　处：《西北地质》2023年第6期71-81,共11页Northwestern Geology

基　　金：中国铜业重点科技项目“青海省格尔木牛苦头及外围铅锌成矿规律研究与潜力评价”(QHHX-KZ-JF2020-001)资助。

摘　　要：东昆仑造山带祁漫塔格地区是青海重要的矽卡岩多金属成矿带,牛苦头矽卡岩型矿床位于该地区中西段,为祁漫塔格地区探明的中-大型矽卡岩型铅锌多金属矿床之一。鉴于矿区成岩成矿时代以及金属成矿物质来源存在争议,笔者通过LA-ICP-MS及热表面电离质谱Re-Os同位素测试技术对锆石及黄铁矿年代学进行了研究。结果表明,牛苦头矿区M1矿段10线钻孔底部成矿花岗岩体年龄分别为(362.2±2.7)Ma、(361.8±3.4)Ma,与主成矿阶段闪锌矿密切共生的黄铁矿Re-Os等时线年龄为(359.2±6.3)Ma。牛苦头矿区矽卡岩铅锌多金属矿床成岩与成矿时代耦合于(362.2±2.7)~(359.2±6.3)Ma,表明该矽卡型铅锌多金属矿床形成于华力西期晚泥盆世。黄铁矿初始187OS/188Os值为0.13±0.24,表明牛苦头铅锌矿床金属成矿物质为壳幔混合来源,形成于晚泥盆世早古生代—晚古生代早期构造-岩浆旋回中碰撞-后碰撞的拉伸背景之下。The Qimantagh area of East Kunlun orogeninc belt is an important skarn-type polymetallic mineralization belt in Qinghai,and the Niukutou deposit is located in the central-western part of this area,which is one of the middle-large Pb-Zn skarn deposits in Qimantagh area.In view of the controversy about the diagenetic and metallogenic age and the source of the metal ore-forming materials of Niukutou ore district,the zircon and pyrite chronology has been studied by LA-ICP-MS and thermal surface ionization mass spectrometry Re-Os isotope testing technology in this paper.The results show that the ages of the ore-forming granite bodies at the bottom of the 10 line drill hole in the M1 ore block of Niukutou ore district are(362.2±2.7)Ma and(361.8±3.4)Ma respectively,and the Re-Os isochron age of the pyrite closely associated with the sphalerite in the main mineralization stage is(359.2±6.3)Ma.This shows that the diagenesis and mineralization age of the skarn Pb-Zn polymetallic deposit in Niukutou ore district are coupled at(362.2±2.7)~(359.2±6.3)Ma,which further indicates that the skarn Pb-Zn polymetallic deposit was formed in the late Devonian of Variscan.The initial 187OS/188Os of pyrite is 0.13±0.24,which indicates that the metal ore-forming materials of Niukutou Pb-Zn deposit are of crust mantle mixed source,and formed under the extensional background of collision-post collision in the tectonic magmatic cycle from Early Paleozoic to early Late Paleozoic at Late Devonian.

关 键 词：Re-Os年代学 成岩与成矿时代耦合 金属成矿物质来源 壳幔混合 

分 类 号：P588.12[天文地球—岩石学] P597.3[天文地球—地质学] P618