Abstract:

Longbohe copper deposit, a structure fractured alteredrock type of copper deposit, is located in the southeast end of AilaoshanRed River tectonic zone, Jinping,Yunnan. The wallrock is sodiumenriched metavolcanic rock, and the alteration consists of chloritization, silicification, pyritization, and sericitization. The voluminal change and compositional migration between metavolcanic rock and mineralizational metavolcanic rocks are calculated based on the geochemical compositions. The results show that, from weakly mineralized metavolcanic rocks to strong mineralized metavolcanic rocks, the volumes increase by about 14% and 12%, respectively, and the contents of SiO2, HREE, metallogenic elements (Cu and S), and proiron elements such as Cr and Ni increase gradually, but the contents of CaO, MnO， LREE, etc., decrease gradually. It suggests that the SiO2, HREE and metallogenic materials, such as Cu， S, etc., are moved into the wallrock by the orebearing fluid, and the CaO, MnO， LREE, etc. are moved out from the wallrock, and the metallogenic materials come mainly from the magmatic hydrothermal.

Key words: Jinping of Yunnan, Longbohe copper deposit, sodiumenriched metavolcanic rocks, compositional migration, mineralization