粤桂边境庞西垌—金山银金矿床特征与成因

GEOLOGICAL CHARACTERISTICS AND GENESIS OF THE PANGXIDONG-JINSHAN Ag-Au DEPOSIT IN YUNKAI TERRAIN,SOUTH CHINA

庞西垌—金山银金矿床位于广东廉江县与广西博白县的交界,是一个以银为主,含有金、铅、锌等伴生有益组分的银多金属矿床。地质地球化学研究结果表明,该矿床是中低温蚀变构造岩型银金矿床。矿床的成矿物质主要来源于前寒武系—寒武系变质岩系,燕山期英桥花岗岩浆活动提供了热源,驱使以大气降水为主含有岩浆热液的混合水循环并对围岩进行淋滤,形成成矿溶液体系;成矿溶液沿多期次活动的庞西垌—金山断裂带运移,在运移过程中与围岩发生蚀变作用,矿床最后定位,矿化与硅化、绢云母化、黄铁矿化关系密切。

The Pangxidong -Jinshan Ag -Au ore deposit is located along the boundary z one between Guangdong and Guangxi Provinces,so uthern China.It is distributed alon g the Pangxidong -Jinshan fault system,and composed mainly of hydro thermally altered deformed rocks an d quartz veins.Based on the geological and geochemi cal research,we can draw a conclusio n as follow:The ore-forming elements came from Precambrian-Cam brian metamorphic rocks,which are t he country rocks of the Ag -Au ore deposit.The ore-forming fluid r esulted from meteoric water with partial magma water from Yingqiao granite magmatism during Yanshan stage.The meteoric water and partial magma water extracted the ore-forming mass during circulation drived by the heat from Yingqiao granite.The ore-forming elements affected the rocks and formed hydrothermal alteration when the fluids flow alone t he Pangxidong -Jinshan fault,of which the deposit is positioned.