【摘要】 对郯庐断裂南段沙溪含铜斑岩体中黑云母和斜长石单矿物的高精度40A r/39A r同位素测定,获得40A r/39A r平均坪年龄为132.62 M a±0.28 M a,40A r/39A r等时线平均年龄为132.59 M a±0.46 M a,而最小平均视年龄86 M a左右可能表示后期的一次热事件,可能对应于斑岩体与Cu-A u矿化有关的热液活动。这些年龄值比前人在该区及邻区获得的K-A r和R b-S r年龄更精确地代表沙溪含铜斑岩体的侵入时代。132.6M a左右的年龄代表着该区含铜(金)斑岩体的侵入时代,可以证实铜(金)斑岩型矿床是在稍后的大规模热液蚀变条件下所形成。更多还原

【Abstract】 The Shaxi porphyrites are composed of diorite-quartz diorite series,forming a medium scale copper deposit near south Tancheng-Lujiang（Tan-Lu） fault belt,central Anhui,east China.Shaxi porphyry Cu-Au deposit occurs in a complex intrusive body composed of quartz diorite porphyry,biotite-quartz diorite porphyry and fine to mediumgrained porphyry diorite along the lower part of Yangtze metallogenic belt.Each biotite and plagioclase samples were analyzed for age determination by the ⁴⁰Ar/³⁹Ar method.The sample yield reproducible ages with a high level of confidence of both average plateau and average isochron ages of 132.62 Ma±0.28 Ma and 132.59 Ma±0.46 Ma respectively,which is more precise than K-Ar and Rb-Sr dating ages made previously and better constrains the times of the main event of porphyry formation of Yanshanian period of igneous intrusive in the Shaxi Cu-Au porphyry deposit.The average minimum apparent age of 86 Ma may represent the thermal event related to Cu-Au mineralizaton in this region.It is believed that the age of around 132.6 Ma can represent the intrusive time in Shaxi region,and the Cu-Au mineralization should occur later by strong thermal event of magmatism.更多还原