Analysis of the Genesis and H−O−S−Pb Isotopic Characteristics of Aqiyin Gold Deposit in the Western Section of the East Kunlun

Aqiyin gold deposit is a newly discovered gold deposit in the western section of East Kunlun in recent years.In order to explore the genesis of the deposit, the characteristics of ore−forming fluid and the source of ore−forming materials, and establish the metallogenic model, the fluid inclusion analysis of pyrite bearing quartz fine mesh vein type gold ore in the metallogenic period was carried out, and the isotopic analysis of fluid H−O, pyrite and arsenopyrite S−Pb in quartz vein was carried out. The results show that the homogenization temperature of inclusions is 167～356.9℃, the salinity is mainly concentrated between 3.21～9.99 wt% NaCl_eqv, and the density is 0.65～0.94 g/cm³. The ore-forming fluid has the characteristics of medium temperature, low salinity and low density. The fluid inclusions in ore bearing quartz vein have δD_v-smow values of −90.3‰～−98.7‰, δ¹⁸O of 9.4‰～11.3‰ and δ³⁴S of 11.6 ‰～13.9 ‰. The Pb isotopes of Au−bearing pyrite vary from 38.067 to 38.651, from 15.598 to 15.681, and from 18.122 to 18.533 for ²⁰⁸Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁶Pb/²⁰⁴Pb ratios, respectively. The values of μ are from 9.49 to 9.61. Combined with the geological background of the Aqiyin gold deposit, the author hold that the ore–bearing hydrothermal fluid is a mixture of metamorphic water and meteoric water, sulfur is mainly derived from dynamic metamorphism, and lead shows the characteristics of lead source in orogenic belt. The genetic type is orogenic (tectonic altered rock type) gold deposit.