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本文采用锆石LA-ICP-MS微区U-Pb测年技术,对冈底斯成矿带东段曲水县达布斑岩Cu(Mo)矿床北部达布矿区含矿斑岩体、南部显角囊含矿花岗闪长斑岩岩体进行了年代学研究,通过对3件岩体样品中单颗粒锆石的分析,达布主矿体花岗闪长斑岩样品206Pb/238U年龄加权平均值为16.5±0.05Ma(n=15,MSWD=3),达布主含矿体二长花岗斑岩样品年龄为16.1±0.13Ma(n=15,MSWD=1.03),南部显角囊矿体花岗闪长斑岩年龄为16.2±0.04Ma(n=13,MSWD=0.0064)。对达布矿床斑岩Cu(Mo)矿床主矿体中4件辉钼矿样品,显角囊矿体中6件辉钼矿样品,分别进行了Re-Os同位素测试,等时线年龄分别为14.6±0.50Ma(MSWD=0.35,主矿体)、14.8±0.23Ma(MSWD=1.3,显角囊)。结合前人研究以及本次测年结果认为:1)达布斑岩铜(钼)矿床岩体侵位的年龄应限定在16Ma左右,成矿时代为14Ma左右,成矿时间差小于0.86Ma,与区域上“成矿瞬时发生”的成矿规律是一致的;2)矿床产出于印度-亚洲大陆板块后碰撞伸展环境。
In this paper, zircon-LA-ICP-MS micro-region U-Pb dating technique is used to study the ore-bearing porphyry in the northern DaBu mining area of the Dabu porphyry Cu (Mo) deposit in the eastern part of the Gangdese metallogenic belt, According to the chronological study on the granodiorite granodiorite intrusive granulite rock mass, the granulite porphyry samples from the main ore body of the Da’erbu granite were analyzed by analyzing the single granulite in the three rock samples. The 206Pb / 238U age The weighted average was 16.5 ± 0.05Ma (n = 15, MSWD = 3). The age of the main Daman granitic porphyrite granodiorite sample was 16.1 ± 0.13Ma (n = 15, MSWD = 1.03) The granodiorite porphyry granodiorite age is 16.2 ± 0.04Ma (n = 13, MSWD = 0.0064). Four samples of molybdenite in the main ore body of the porphyry Cu (Mo) deposit in Dabu deposit and six molybdenite samples in the radioclinal pocket were respectively subjected to Re-Os isotope test. The isochronal ages were 14.6 ± 0.50Ma (MSWD = 0.35, main orebody), 14.8 ± 0.23Ma (MSWD = 1.3, Angular capsule). Combined with the previous studies and the results of this survey, it is concluded that: 1) The age of the emplacement of the rock mass in the Dabu porphyry copper-molybdenum deposit should be limited to about 16Ma, the metallogenic age is about 14Ma, the metallogenic time difference is less than 0.86Ma, In the area, the metallogenic regularity of “metallogenic instantaneous ” is consistent; 2) The deposit is produced in the post-collision extensional environment of India-Asia continental plate.