Rules Of Ore-controlling Structures And Forecast Of Orebody Location Of Dayin'gezhuang Gold Deposit In Jiaodong Region

Dayin'gezhuang gold deposit, hosted in altered granitoid, is a typical large-scale altered deposit located in the fracture zone of the center part of Zhaoping fault belt, northwest Shandong province. Basing on systemic geological field observations and exploring-mining documentation, the paper analysed comprehensively geological characteristics, ore-controlling structures, mineralization networks characteristics of the deposit and studied orebody distribution regularities, and prospected the most advantageous targets for new ore bodies.There are many faults in the mining field that control the orebodies distribution. The Zhaoping fault, being not only the ore-controling but also the ore fluids transmitting and ore hosting structure, occurres along the interface of Linglong granite and Jiaodong Group. Most of the mined ore bodiesis are hosted in the altered Linglong granite which located on the footwall of the Zhaoping fault. The Dayin'gezhuang fault formed later than the Zhaoping fault, and might be earlier than mineralization event or syn-mineralization. The Dayin'gezhuang fault divided the ore bodies into two groups, north ore bodies group and south ore bosy group. The north group is named No.2 orebodies group, and the south part is named No.1 orebodies group. The No.1 and the No.2 groups are different in alteration and mineralization characteristics. The Nanzhoujia fault is a shallow and brittle fault after mineralization. The Nangou fault is a basement structure .The Nanzhoujia fault and the Nangou fault have no obvious control on gold mineralization.The deposit show obvious structure-alteration-mineralization zonings. Structure zones controlled the alteration zones and mineralization zones, forming regularly distributed mineralization and alteration patterns. From proximal to distal of the Zhaoping fault, alteration zones are pyrite-beresite, beresitizated cataclastic granite, and beresitizated granite.Orebody distribution in the Dayin'gezhuang gold deposit is generally controlled by faults and fractures of different scale. The structure control on ore bodies varies with depth. In shallow, the main ore-controlling structures confined the altered belt distribution. Secondary structures control the specific ore bodies'positions, shapes and partial enrichment of gold mineralization. Orebodies reveal complex branch-vein shape with various mineralization types and grades. With the increase of depth, the effect of shallow-brittle secondary ore-controlling structures gradually reduced. Main structure controls not only altered belt distribution but also the patterns of the orebodies. Orebodies show simple large vein shapes which varies with main structures, single mineralization type and stable in grades.Thick parts of No.1 and No.2 orebodies group pitch NE.The main orebodies are located within Zhaoping fault belt. Some NEE trending secondary structures, structures parallel to Zhaoping fault,"y"style structures constituted by main structure and secondary structures, rhombic zones confined by NEE structures and NW structures, sections of great thickness of tectonite and fault gouge, NE pitching direction of the known orebodies are all favorable targets for gold mineralization.The NE trending direction of known orebodies is the key forecast zone where we may probably get 158421 kg AU.