青海东昆仑瑙木浑金矿蚀变绢云母Ar-Ar年龄、石英闪长岩锆石U-Pb年龄和岩石地球化学特征

摘要

东昆仑地区金矿资源丰富,是我国著名的“金腰带”,瑙木浑金矿位于该区昆北加里东弧后裂陷成矿带.地球化学研究表明,与金矿体空间关系密切的石英闪长岩为高钾钙碱性系列,具有安第斯型活动大陆边缘火成岩的构造属性.获得绢云母”40Ar-39 Ar坪年龄为227.84土1.13Ma;获得石英闪长岩锆石U-Pb年龄为235.8±0.8Ma,形成于三叠纪中期,与阿尼玛卿洋向北俯冲作用有关.研究认为石英闪长岩对瑙木浑金矿形成具有重要意义,印支期是东昆仑地区金矿主成矿期.%East Kunlun is endowed with abundant gold resources and is nicknamed the "Gold Belt" in China.The Naomuhun gold deposit is just located in the metallogenic belt of Caledonian post-arc rifting in the north of East Kunlun.Geochemical studies indicate that quartz diorite which is spatially related to gold-bearing rock is of high-K calc-alkaline series and has the attribute of Andean type epicontinental igneous tectonics.40Ar-39Ar dating yields an average age of 227.84±1.13Ma for sericite.Zircon U-Pb dating yields an age of 235.8±0.8Ma for quartz diorite,suggesting that it formed due to northward subduction of the Animating ocean basin during the middle triassic period.Indosinian is the major gold metallogenic epoch of the East Kunlun area.Therefore,this study is of great importance to further understanding the formation of the Naomuhun gold deposit.