延边地区闹枝铜金矿床绢云母^(40)Ar-^(39)Ar测年及成矿时代探讨

^(40)Ar/^(39)Ar Dating of Sericite and Discussion onMetallogenic Epoch from Naozhi Au—Cu deposit in Yanbian

闹枝矿床是延边地区著名的热液铜金矿床。为明确其成矿时代,进行了硫化物石英脉中的脉石矿物绢云母的^(40)Ar/^(39)Ar测年。实验测试获11组数据,坪年龄为(128.6±1.4)Ma,等时线年龄为(130±30)Ma。结合已有的相关成果,认为其应代表该矿床成矿作用的上限,略早于延边地区斑岩型铜金矿、浅成低、高硫化型金矿床,为中生代古太平洋板块向欧亚板块不同方向俯冲的产物。

Naozhi depost is a famous hydrothermal copper gold deposit in Yanbian area.In order to confirm the epoch,^(40)Ar/^(39)Ar dating of gangue mineral sericite from sulfide-quartz veins was undertaken.11 groups data were obtained,yielding a isochron age of(130±30)Ma and a^(40)Ar/^(39)Ar plateau age of(128.6±1.4)Ma.Combined with established research results,it should represent the upper limit of mineralization of the deposit.It is suggested that the mineralization of Naozhi deposit occurred after 128 Ma,it is slightly earlier than the porphyry copper-gold deposit,high-sulphidation and low sulphidation hydrothermal gold deposit in yanbian area.It was resulted from different direction subduction of the Pacific plate underneath the Eurasian plate.