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秋树湾铜钼矿床是秦岭造山带东段最大的斑岩-夕卡岩型铜钼矿床,通过对矿石中6个辉钼矿样品的 Re-Os 同位素分析,得到了145.57±1.80～147.98±2.21Ma 的模式年龄(平均为146.42±1.77Ma)及一个相关性很好的等时线年龄147±4Ma,表明秋树湾铜钼矿床形成于晚侏罗世,与其以北的华北克拉通南缘的主要斑岩型钼矿床及位于扬子克拉通北缘的长江中下游铁铜矿床的大规模成矿时间一致,是中国东部中生代第2期大规模成矿作用的产物。秋树湾铜钼矿床辉钼矿的含铼量平均达151.8×10~(-6),明显高于华北克拉通南缘钼矿带同期形成的钼矿床(16.13×10~(-6)～28.09×10~(-6)),认为主要是由于两者成矿元素 Cu/Mo 比值的不同造成的;结合矿石硫同位素特征,认为矿床的物质主要来源于下地壳。
The Qiuhuwan copper-molybdenum deposit is the largest porphyry-skarn-type copper-molybdenum deposit in the eastern segment of the Qinling orogenic belt. The Re-Os isotopic analysis of six molybdenite samples in ore shows 145.57 ± 1.80 ~ 147.98 ± 2.21Ma model age (average 146.42 ± 1.77Ma) and a well-correlated isochron age of 147 ± 4Ma, indicating that the Qiuhuwan copper-molybdenum deposit formed in the Late Jurassic, with its north of North China Craton The main porphyry-type molybdenum deposit in the margin and the large-scale mineralization time of the middle-lower reaches of the Yangtze River iron-copper deposit located in the northern margin of the Yangtze craton are coincident with the large-scale mineralization in the second Mesozoic in eastern China. The rhenium content of molybdenite in Qiuhuwan copper-molybdenum deposit is 151.8 × 10 ~ (-6) on average, which is obviously higher than that of the molybdenum deposit (16.13 × 10 ~ (-6) ~ 28.09 × 10 -6), which is mainly attributed to the difference of the Cu / Mo ratio between the two ore-forming elements. According to the sulfur isotope characteristics of the ore, the material of the deposit is considered to be mainly derived from the lower crust.