青海东昆仑鸭子沟多金属矿的成矿年代学研究  

Geochronological Study on Yazigou Polymetallic Deposit in Eastern Kunlun,Qinhai Province

作　　者：李世金[1] 孙丰月[1] 丰成友[2] 刘振宏[3] 赵俊伟[1] 李玉春[4] 王松[2] 

机构地区：[1]吉林大学地球科学学院,长春130061 [2]中国地质科学院矿产资源研究所,北京100037 [3]青海省国土资源厅,西宁810001 [4]青海省地质调查院,西宁810012

出　　处：《地质学报》2008年第7期949-955,共7页Acta Geologica Sinica

基　　金：“十一五”国家科技支撑计划课题“柴达木南北缘铜铅锌矿成矿规律及大型资源基地评价技术示范研究”(编号2006BAB01A06)资助的成果

摘　　要：鸭子沟多金属矿是近年来青海省地质调查院在东昆仑祁漫塔格地区发现的一个具有斑岩型成矿特点的矿床。本文利用SHRIMP锆石U-Pb和辉钼矿Re-Os同位素对含矿斑岩体和矿石进行了精细成岩成矿时代测定,获得钾长花岗斑岩的SHRIMP锆石U-Pb年龄为224.0±1.6 Ma(n=15,MSWD=1.2),矿石的辉钼矿Re-Os等时线年龄为224.7±3.4Ma(n=11,MSWD=2.7),成岩与成矿的时间一致,正好属于印支晚期东昆仑地区发生强烈壳-幔相互作用并导致产生大量岩浆-热液活动和成矿作用的时期。钾长花岗斑岩与矿床具有密切的时空和成因联系,斑岩体在时空分布上与矿区内的闪长岩、辉绿玢岩及辉长岩等幔源脉体紧密相伴,推测同属壳-幔相互作用的产物。成岩、成矿的年代学研究表明,矿床形成的地球动力学背景与东昆仑地区印支晚期的区域动力学背景相一致,同时区内具有较大的寻找斑岩型矿床的潜力。The Yazigou polymetallic deposit, discovered recently by the Qinghai Geological Survey in the Qimantage area of East Kunlun Mountain, Qinghai Province, is characterized by porphyry-type mineralization. The authors have conducted geochronological study on the samples from the ore-bearing porphyry and orebodies by SHRIMP zircon U-Pb and molybdenite Re-Os dating, respectively. The zircon U-Pb age for the K-feldspar granitic porphyry is 224 ± 1.6 Ma while the Re-Os age of ore molybdenite is 224.7±3.4 Ma, suggesting that diagenesis and mineralization took place coevally with the intense crustmantle interaction in the East Kunlun orogenic belt in Late Indosinian. Meanwhile, the interaction between crust and mantle resulted in large-scale magmatic-hydrothermal activities and metallogeny. The K-feldspar granitic porphyry is closely related to polymetallic mineralization and the mantle-derived diorite, diabase and gabbro in the area both temporally and spatially. It is refered that that the magmatic intrusives mentioned above are all the products of the crust-mantle interaction. Based on the geochronological study, it is proposed that the Yazigou deposit has the same geodynamical setting as the whole Eastern Kunlun orogenic belt in Late Indosinian. Meanwhile, the authors also point out that there are good potentials for porphyry deposit prospecting in the area.

关 键 词：斑岩型矿床 U-PB RE-OS 锆石 辉钼矿 鸭子沟 东昆仑 

分 类 号：P597.3[天文地球—地球化学]