粤北红岭钨矿中辉钼矿Re-Os同位素年代学及其地质意义

Re-Os isotopic chronology of molybdenites from Hongling tungsten deposit of Guangdong Province and its geological significance

粤北红岭钨矿为产在热水复式岩体之中的中型钨多金属矿床,矿化类型为石英脉型黑钨矿化和蚀变花岗岩型白钨矿化。对矿区含矿石英脉中8个辉钼矿样品进行Re-Os同位素测定,获得等时线年龄及模式年龄的加权平均值分别为（159.1±1.5）Ma和（158.8±0.88）Ma。等时线纵截距为-0.010±0.041,说明样品中不存在可测定的初始187Os。统计表明南岭地区中东段钨锡矿床的成矿年龄多集中在150～160 Ma。粤北已有的几个钨矿成矿年龄与区域燕山期花岗岩大规模侵位时期一致,表明南岭地区花岗岩成岩成矿可能不存在明显的时差。

Located in the middle part of Reshui composite pluton,the Hongling tungsten deposit is a medium size tungsten-ploymetallic deposit.Tungsten mineralizations in this deposit include quartz vein wolframite type and altered granitic scheelite type.Rhenium and osmium isotopic dating of 8 molybdenite samples from the Hongling quartz vein-type tungsten deposit has yielded a precise isochron age of（159.1±1.5） Ma and a weighted average model age of（158.8±0.88） Ma.The intercept of isochron is-0.010±0.041,suggesting that there is no measurable normal Os in these molybdenite samples.Statistics of precise ore-forming ages of WSn deposits from eastern and central Nanling region show that ore-forming ages are concentrated mostly in the range of 150～160 Ma,corresponding to the main periods of large-scale granitic emplacement in this region.The results obtained by the authors show that there is no distinct age gap between tungsten mineralization and granite intrusion in Nanling region.