Abstract:

Ore genesis and source of ore-forming materials are always be debated in the study of the metallogenic theory and ore prospecting. In the paper, helium and argon isotopic characteristics of the pyrite from five gold ore samples formed in different stages are analyzed. It is showed that the R/R_a ratio in the fluid ranges from 0.008 33 to 3.612 00, with an average of 1.400 00; the ⁴⁰Ar/³⁶Ar ratio ranges from 465.7 to 4 674.7, the ratio of ⁴He/⁴⁰Ar^* varies from 0.36 to 1.36. The ratio of the mantle fluid in ore-forming fluid is from 3.73% to 45.87%，average value is 17.67%. Combined with the characteristics of H-O isotope, magmatic rock, wall rock alteration and fluid inclusion etc., it is suggested that ore-forming fluid belongs to the mixture of mantle-derived and crustal-derived fluid. It is mainly derived from the crust, and mixed by the mantle-derived fluid and the small amount of meteoric water in the metallogenic process.

Key words: Denggezhuang, helium and argon isotope, fluid inclusion, crustal fluid, mantle fluid, gold deposit