Metallogenic Characteristics of Western Low Altered Tin-Copper Polymetallic Deposit and Its Prospecting Significance in East Part of Gejiu, Yunnan

In this paper, tin-copper polymetallic deposit in western low of east part of Gejiu is studied through a systematic analysis of its geological setting, geological characteristics of the deposit, characteristics of alterations zoning, geochemical component of altered granite, and deep exploration experience. The results show that the deposit is a part of diverse magmatic hydrothermal mineralization system, which often occurs in the inner altered granite, especially the edge and transition facies. It is a high-temperature magmatic hydrothermal deposit combining with the post-gas-liquid mineralization by the decomposition and gasification of magma in early stage and the alteration of magma intrusion in later stage. The deposit has close relationship with wall-rock alteration, especially potash feldspathization, pyritization, fluoritization and tourmalinization. The main metallic elements of the deposit include Cu, Sn, W; the elements Ag, Mo, Bi, Cd, In, U are the comprehensive utilized elements. The discovery of this type of deposits has great significance for deep exploration and further resources exploration in Gejiu mining area.