阳山金矿矿化-未矿化岩脉中锆石年代学研究  

Zircon chronology of mineralized andunmineralized dikes in Yangshan gold deposit

作　　者：李小宇 赵静[1] LI Xiaoyu;ZHAO Jing(Chengdu University of Technology,College of Earth Sciences,Chengdu,610059,Sichuan,China)

机构地区：[1]成都理工大学地球科学学院,四川成都610059

出　　处：《四川冶金》2023年第1期31-35,共5页Sichuan Metallurgy

摘　　要：阳山金矿位于扬子、中朝板块及松潘-甘孜褶皱带所夹持的三角区域内。本文对矿区内矿化-未矿化花岗斑岩脉中锆石进行了LA-ICP-MS U-Pb年龄测定,探讨岩脉与金成矿的关系。结果显示,矿化与未矿化花岗斑岩脉内锆石呈自形柱状,环带韵律结构发育,具岩浆锆石特征。锆石206Pb-238U协和年龄可分为2组,分别为(727±28)Ma与(212.5±2.6)Ma,其中第1组年龄为捕获新元古代华南板块碧口群锆石;第2组年龄为花岗斑岩结晶年龄,且该期岩浆活动与金成矿作用密切相关。早-中三叠世扬子-秦岭微陆块与华南板块发生碰撞,并逐渐由挤压体系向拉伸构造体系转化,晚三叠世岩石圈发生大面积拆沉,导致秦岭碧口地块发生熔融形成岩浆,最终形成花岗斑岩脉,进一步为金矿的形成奠定基础。The Yangshan gold deposit is located in the triangular region sandwiched by the Yangtze,ZhongKorean plate and Songpan-Ganzi fold belt.In this paper,LA-ICP-MS U-Pb dating of zircons in mineralized and unmineralized granitic porphyry dikes in the mining area is carried out to explore the relationship between dikes and gold mineralization.The results show that the zircons in the mineralized and unmineralized granitic porphyry veins are self-shaped and columnar,and the zonal rhythmic structure is developed,showing the characteristics of magmatic zircons.Zircon206Pb-238U age can be divided into two groups,which are(727±28)Ma and(212.5±2.6)Ma,respectively.The first group dates from the Bikou Group of the South China Plate in the NeoProterozoic.The age of the second group represents the crystallization age of the granite porphyry,and the magmatic activity in this period is closely related to gold mineralization.The Yangzi-Qinling microlandmass collided with the South China plate in the Early and Middle Triassic,and gradually transformed from extrusion system to extensional tectonic system.In the late Triassic,a large area of lithosphere was removed,resulting in the melting of the Qinling Bikou block to form magma,and finally the formation of granite porphyry dikes,which further laid the foundation for the formation of gold deposits.

关 键 词：阳山金矿 锆石U-PB年代学 阴极发光 甘肃 

分 类 号：P57[天文地球—矿物学]