冈底斯中段岗讲斑岩铜钼矿床锆石U-Pb和辉钼矿Re-Os年代学及其地质意义

发布时间：2018-04-06 05:35

本文选题：地球化学　切入点：锆石U-Pb测年　出处：《地球科学》2017年03期

【摘要】：岗讲铜钼矿床是西藏冈底斯成矿带中段典型的斑岩型矿床,岗讲矿床成岩成矿时代、岩浆演化过程及其与成岩成矿关系尚不明确,利用LA-ICP-MS锆石U-Pb定年方法对岗讲矿区主要岩体二长花岗斑岩、花岗闪长斑岩和英云闪长玢岩成岩时代进行研究,获得锆石U-Pb年龄加权平均值分别为16.6±0.3Ma(MSWD=0.94,n=10)、16.1±0.2Ma(MSWD=1.07,n=12)、14.4±0.4Ma(MSWD=1.12,n=7);同时采用辉钼矿Re-Os同位素测年方法首次对岗讲矿床石英硫化物脉中的辉钼矿进行定年,获得12件辉钼矿Re-Os同位素模式年龄集中于13.24±0.20Ma~13.55±0.22Ma,加权平均年龄为13.4±0.1Ma(MSWD=0.65),等时线年龄为13.6±1.6Ma(MSWD=1.2).结果表明:(1)岗讲矿区复式岩体侵入序列为含巨斑黑云二长花岗岩-二长花岗斑岩-花岗闪长斑岩-流纹斑岩(深部定名为英云闪长玢岩),成岩时限为16.6~14.4Ma,成矿时代为13.4Ma左右,成岩成矿是一个连续的岩浆演化过程;(2)辉钼矿中Re含量为155.4~171.1μg/g,均值为162.9μg/g,指示其成矿物质中有幔源成分的加入;(3)矿床产出于中新世印度-亚洲大陆碰撞后伸展构造环境.
[Abstract]:The Gangliao copper-molybdenum deposit is a typical porphyry deposit in the middle section of the Gangdis metallogenic belt in Tibet. The magmatic evolution process and its relationship with the diagenesis and metallogenesis are unclear in the diagenetic and metallogenic age of the Gangliao deposit.LA-ICP-MS zircon U-Pb dating method was used to study the diagenetic ages of the Erchanggranite porphyry, granodiorite porphyry and dolomite diorite porphyrite in the Ganglei ore area.The Re-Os isotopic model age of 12 molybdenum ores is 13.24 卤0.20Ma~13.55 卤0.22 Ma, the weighted average age is 13.4 卤0.1 Ma, and the isochron age is 13.6 卤1.6 Ma.The results show that the intrusive sequence of the complex intrusive body in the Gonghuiao ore area is composed of granitic granitic granite, granodiorite porphyry, granodiorite porphyry and stream porphyry. The diagenetic time limit is 16.6 ~ 14.4 Ma. and the metallogenic age is about 13.4Ma.The ore-forming process is a continuous magmatic evolution process.) the re content in molybdenum is 155.4N 171.1 渭 g / g, with a mean value of 162.9 渭 g / g, indicating that mantle-derived elements were added to the ore-forming material, indicating that the deposit occurred in the post-Miocene Indo-Asian continental collision extensional tectonic environment.
【作者单位】：中国地质大学资源学院;昆明理工大学国土资源工程学院;云南铜业(集团)有限公司;安徽省地质矿产勘查局326地质队;拉萨天利矿业有限公司;
【基金】：云南铜业(集团)有限公司和中国地质大学(武汉)合作项目(No.2010026410)
【分类号】：P597.3;P618.41;P618.65

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