青海东昆仑鸭子沟斑岩型铜(钼)矿区辉钼矿铼-锇同位素年龄及地质意义

首次对鸭子沟铜(钼)矿区辉钼矿进行了Re-Os同位素定年。样品的模式年龄介于213.8～231.0Ma之间,11件样品得到187Re-187Os等时线年龄为224.7±3.4Ma(n=11,MSWD=2.7)。文章在分析祁漫塔格-都兰成矿带鸭子沟铜(钼)矿区地质特征和区域成矿特征的基础上,认为该成果不仅说明鸭子沟铜(钼)矿化作用发生于晚印支期,而且在区域成找矿研究上也具有重要的地质意义,揭示了东昆仑地区晚印支-燕山期后碰撞阶段斑岩型Cu、Mo成找矿的良好前景。

Re-Os Age of Molybdenite from the Yazigou Copper (Molybdenum) Mineralized Area in Eastern Kunlun of Qinghai Province, and Its Geological Significance

Yazigou copper(molybdenum) mineralized area is located in the Qimantage area of the Qimantage-Dulan mineral belt in the southwest rim of Qadam basin.The porphyry copper molybdenum formed in multi-mineral deposit,which was composed of the Triassic moyite and granodiorite porphyries(open area is about 0.6 km2).The alteration of ore-controlling granitic porphyry and its wall rock is not strong,only up to the propylite alteration.The space distribution of copper molybdenum ore body,rock mass and scale are controlled by the moyite deposit.This paper for the first time gives the highly precise Re-Os age of molybdenite from the Yazigou copper(molybdenum) mineralized area.The Re-Os model ages of 11 molybdenite samples from the mineralized area vary from(217.0±3.2) Ma to(227.0±4.0) Ma,yielding an isochron age of(224.7±3.4) Ma.Combined with the analysis of geological and regional mineral characteristics of copper(molybdenum) mine in Yazigou of Qimantage-Dulan mineral belt,it indicates that this study does not only constrain the forming time of copper(molybdenum) mineral in the late Indosinian,but also play an important role in the research of regional mine exploration and in revealing better ore-finding prospects of porphyry Cu,Mo deposits formed in the late Indosinian-Yanshannian post-collisional stage in east Kunlun area.