甘肃成县庙沟铅锌矿成矿环境及控矿构造分析

Ore-Forming Environment and Ore-Controlling Structures of the Miaogou Lead-Zinc Deposit in Chengxian County,Gansu Province

甘肃成县庙沟铅锌矿床位于秦岭造山带西部,西(和)-成(县)铅锌矿田东段,矿床类型属喷流沉积型。岩石、矿石微量元素特征表明矿区形成时为贫氧环境;稀土元素Eu异常特征反映矿区古成矿流体温度较低,与厂坝-李家沟铅锌矿床形成条件相似; Ce异常特征亦反映矿区形成于贫氧的还原环境。通过探矿工程揭露,认为银洞湾矿段受其北东侧断层(F)与南西侧陡倾矿体共同控制,构造挤压是矿区形成高品位矿石的主要原因。结合区域上的研究成果,建立了矿区成矿模式,指出矿区应注意寻找块状、网脉状矿体,赋存于标高1700～1500m空间内的矿体,以及被断层(F)断失的矿体。

The Miaogou lead-zinc deposit is located in the eastern of Xihe-Chengxian lead-zinc ore cluster which belongs to the western of Qinling orogenic belt,belonging to a sedimentary exhalative deposit. The analytical results of trace elements indicate that forming environment of rocks and orebodies were under oxygen-poor condition;the characteristics of Eu anomaly reflect the lower temperature of paleo-mineralized fluids in Miaogou area,which is similar to the formation conditions of the Changba-Lijiagou lead-zinc deposit;the anomalous characteristics of Ce also reflect the the environment of formation was reduction. According to the exploration engineering( tunnels and drillings),it is considered that Yindongwan ore section is jointly controlled by the northeast side fault( F) and steep-dip orebody on the southwest side,and structural compression of intrusive is the main reason for forming high grade ore. Finally,based on regional research achievements,the metallogenic model of the Miaogou area is established. It is pointed out that we should pay attention to finding massive and stockwork orebodies,and the orebodies were hosted in the space of the elevation of 1700-1500 m,and the orebodies were lost by the fault( F).