A new metal ore Karst deposition form - Case study for dolomite residual deposit in Dongxiang copper mine, Jiangxi Province, China

摘要

The Kcd(Karst colluvium and deluvium) deposit of Dongxiang copper mine had long been considered as a kind of ancient diluvium, alluvium and proluvium in Cretaceous Karst depression. Based on lithology and morphology analysis of Kcd, and further research for regional hydrogeology and hydrogeochemistry, it was considered as a new special Karst deposition form of metal ore in this project. In the oxidation zone of sulfide mineral deposit, Kcd was a deposition mixture of dolomite powder (sand) and eluvium of dolomite wall rock, which were generated by the action of sulfuric acid water on wall rock, and the collapse deposition from the overlying K_2n red beds. This kind of deposition was still generating and developing today. The monoclinal structure, primary sulfide mineral deposit occurred in clastic rock and claystone, dolomite and siliceous dolomite with 160m deep in underground water system, all that provided the development conditions of metal ore Karst deposition. This viewpoint could not only guide the copper ore exploration of Dongxiang type, but also provide a good case for Karst development in sulfide mineral areas.