安徽池州马头铜钼矿床锆石年龄与辉钼矿Re-Os同位素测定的地质意义

Geological significance of zircon age and Re-Os isotopic measurement on molybdenite from Matou Cu-Mo polymetallic deposit Chizhou,Anhui province,China

安徽池州马头铜钼多金属矿床是江南过渡带池州段典型斑岩型铜钼矿床之一。对矿区钻孔中不同深度花岗闪长（斑）岩和钾长花岗岩采用高精度的LA-ICP-MS锆石U-Pb测年。结果表明：花岗闪长（斑）岩形成相对较早（144.5~145.8 Ma）,而钾长花岗岩侵位稍晚（141.5 Ma）,二者均为燕山晚期（晚侏罗-早白垩世）岩浆作用的产物。对矿区13件辉钼矿样品采用Re-Os同位素测年,获得Re-Os等时线年龄为（148±3）Ma。考虑到矿体的形成和分布与岩体蚀变关系较为密切,进一步确证安徽池州马头铜钼多金属矿床成岩与成矿作用为同一构造-岩浆热事件的产物。

Matou Cu-Mo polymetallic deposit is one of the typical porphyry Cu-Mo deposits in Chizhou segment of Jiangnan transitional zone,Anhui province.The high precision LA-ICP-MS zircon U-Pb dating is used for granodiorite（porphyry） of mine drill in this area.Zircon LA-ICP-MS U-Pb dating of four drilling samples,yielded ages of144.5-145.8 Ma for the granodiorite-porphyry,and of 141.5 Ma for the moyite,indicating that they are all the products of the Late-Yanshanian（late-Jurassic to early Cretaceous） magmatism.Meanwhile,Re-Os isotopic age analysis of thirteen molybdenite yielded a weighted average model age of（148±3） Ma.Considered the relationship between the distribution and forming of the ore closely related with the rock alteration,the above information suggests that the diagenesis and the metallogenesis of the Matou Cu-Mo polymetallic deposit are the products of the same tectonic-magamtic thermal events.