胶东地区牟乳成矿带金青顶金矿床地质特征与成因分析

Geological characteristics and genetic analysis of Jinqingding gold deposits in Muping-Rushan metallogenic belt of Jiaodong area

金青顶金矿床位于华北克拉通东缘的牟平—乳山成矿带中段。本文详细分析了该矿床的地质特征和矿床成因,认为:矿床围岩为新元古代昆嵛山中粗粒二长花岗岩;Ⅱ号矿体为主体,平均厚度1.75 m,平均金品位9.5×10^(-6);主要金属矿物为黄铁矿,非金属矿物为石英、绢云母等;硫、铅同位素表现出与昆嵛山岩体及荆山群地层的一致性,说明相互间具有演化继承关系;氢氧同位素特征表明热液主要来自岩浆水;成矿年龄集中在125~115 Ma之间,成矿为短时间内完成,由同一成矿体系作用、形成于岩浆期后浅成中低温环境。

Jinqingding gold deposit is located in the middle section of the Muping-Rushan metallogenic belt on the eastern edge of the North China craton.The geological characteristics and genesis of the deposit were analyzed in detail in this paper.It is considered that the surrounding rock of the deposit is the Neoproterozoic medium-coarse grained monzogranite in Kunyu Mountain.The ore body II is the main body,with an average thickness of 1.75 m and an average Au grade of 9.5×10^(-6).Pyrite was identified as the main metallic mineral,while quartz,sericite,and other non-metallic minerals are also present.The sulfur and lead isotopes showed consistency with the Kunlun Mountain rock mass and the Jingshan Group strata,indicating that there was an evolutionary inheritance relationship between them.Hydrogen-oxygen isotopic signatures suggested that hydrothermal fluids mainly come from magmatic water.The mineralization age is estimated to be between 125~115 Ma,and the mineralization was completed in a short time,which is formed by the same metallogenic system and formed in a shallow medium and low temperature environment after the magma period.