胶东邓格庄金矿地质特征与深部预测

Geological characteristics and metallogenic prognosis of the Denggezhuang gold deposit in Jiaodong peninsula

邓格庄金矿床是胶东东部牟平—乳山成矿带内典型的大型石英脉型金矿床,对其研究和开发具有重要的理论意义和经济价值。矿体产于荆山群和昆嵛山岩体接触部位及其附近地带,赋矿主岩为昆嵛山二长花岗岩,近矿围岩蚀变类型多样,分带明显,成矿阶段具有多期多阶段特征,受与金牛山断裂带呈"入"字型的NNE向次级断裂控制。根据"三位一体"找矿模式,提出了与成矿同期的侵入岩和早白垩世岩浆岩二级成矿地质体概念。荆山群变质岩是金成矿的催化剂,胶东群提供了部分金等成矿物质;岩浆活动提供热源和成矿热液;断裂构造提供导矿和容矿空间,在断裂构造转折处,产状急剧变化处和分支复合的部位,以及不同断裂交汇处有利于成矿物质的聚集。结合矿体金品位和厚度等参数填图结果,探讨了矿化富集规律,推测Ⅰ2-2矿体94线北东向深部-400～-1 100 m标高可能存在较好的找矿远景。

The Denggezhuang gold deposit is one of the most typical quartz vein gold deposits in the Muping-Rushan metallogenic belt in Jiaodong peninsula,and hence it has great academic significance and economic value.Ore bodies are located in the Kunyushan rock mass close to the contact zone between Jingshan Group metamorphic rocks and Kunyushan rock mass.Wall rock alterations of the ore deposit are relatively well developed,characterized by multiple stages and significant zonal structure.Ore bodies are controlled by the NNE-trending sub-fractures west of Jinniushan fracture zone.Based on a study of the ＂three in one＂ ore-forming model,the authors hold that the formation age of the vein rock is the same as the ore-forming age,and this vein rock and early Cretaceous magmatic rock are respectively Ⅰand Ⅱ grade ore-forming geological bodies.Jingshan Group metamorphic rock served as the activator,Jiaodong Group partially provided ore materials,magmatism provided heat source for multiple ore-forming fluids,and fractures played the role of dynamics and location space.The precipitation of ore-forming materials usually occurred in the locations of abrupt change of the attitudes of fractures and the branching and compounding of different faults.Combined with the results of vertical zoning of gold grades and thickness mapping,this paper summarizes prospecting criteria,discusses the concentration rules of gold mineralization,and suggests that at the depth of-400～1000m in the northeast direction of No.94 exploration line of No.Ⅰ 2-2 ore body there may exist favorable prospecting potential.