GEOCHEMISTRY OF ORE FLUIDS AND GENESIS OF LONG- SHAN Au-Sb DEPOSIT, WEST HUNAN, CHINA
Liang Huaying(Institute of Geochemistry, (Guangzhou Branch) Academia Sinica, Guangzhou 510640)
The Longshan Au-Sb deposit occurs in the well-known gold belt of western Hunan. The Au-Sb deposit consists of a series of hydrothermal veins emplaced in faults in the Sininia Jiangkou Group slates. Two periods of ore deposition are distinguished as follows: I. Cu-Pb-Au and II. Sb-Au.This paper focuses on the geochemical features of the Longshan Au-Sb deposit, including mineralization temperature, the salinity, composition and oxygen and hydrogen isotopic characteristics' of ore fluids and lead isotopes, trace elements and rare earth elements. It is considered that the Jiangkou Group slates are the source rocks for Sb-Ar mineralization, while the ore-forming material for Cu-Pb-Au mineralization is derived from the underlying strata. It is also considered that the ore fluids came from meteoric waters, and gold was transported mainly in the form of coordinate ions such as Au(HS)2- and Au(S2)- and aurum-atinomy coordinate ions. The Au-Sb deposit is a typical reworked deposit.