胶东大尹格庄金矿床控矿显微构造特征

Ore-controlling microstructure characteristics of Dayin'gezhuang gold deposit in Jiaodong peninsula

大尹格庄金矿床为招平断裂带中部的大型蚀变岩型金矿床,矿体的产出严格受招平断裂带控制。文中利用显微构造特征、显微运动学标志观测以及显微裂隙统计计算,来探讨大尹格庄金矿床控矿构造的变形、演化及与金成矿的关系。研究表明:大尹格庄金矿床控矿构造以脆-韧性变形为特征;显微运动学标志揭示控矿断裂发生过左行剪切向右行剪切的转变;显微裂隙统计计算表明,成矿前后主应力方位发生NWW→NE→NW的转变,伴随着构造差应力大→小→大的变化。金成矿作用发生在剪压变形向剪张变形转换阶段。

Dayin＇ gezhuang gold deposit is an altered rock gold deposit located in the northern and middle part of the Zhaoyuan-Pingdu fault belt. The ore bodies are strictly controlled by the fault structures. In this paper, microstructure observation and micro-cracks statistics is used to reveal the deformation and evolution characteristics of orecontrolling structures and their contribution to gold mineralization. It is proved that ore-controlling structures in Dayin＇ gezhuang gold deposit are characterized with brittle-ductile deformation. Micro-kinecmatic markers suggest that the fault structures once experienced a transformation from left-lateral shearing to dextral shearing. Furthermore; microcracks statistics and calculation indicates that the maximun principal compressive stress directions varied from NWW to NE and then to NW, and the differential stress changed from big to small and then to big during the mineralization process. Gold mineralization is confirmed to take place at the stage.when fault structure deformation transformed from compression-shearing to extension-shearing.