Objective The skarn ore body of Jiama porphyry and skarn type copper-polymetallic mineral system, in Xizang, China has a unique mineral zoning of metal and skarn minerals. At present, there are two shortcomings in the numerical simulation research on the mineralization of skarn deposits: ①The chemical reaction system is too simplified to analyze the factors controlling the precipitation of single metal elements, and the specific analysis of the influence of redox state and pH value on the mineralization of skarn deposits; ②Previous numerical simulation studies focused on skarn deposits near the contact zone between magmatic rocks and carbonate rocks, and lacked numerical simulation studies on the mineralization process of skarn dominated by hydrothermal fluids.

Methods In order to promote the dynamic and quantification of the mineralization process of the skarn deposit, a two-dimensional numerical simulation model coupling thermal transfer, fluid flow and chemical reaction has been established based on the exploration line profile and fluid inclusion data of the skarn ore body in the Jiama deposit, aiming at studying the formation mechanism of mineral zonation characteristics of the skarn ore body in the Jiama deposit.

Results The model results show that the mineral zonation of skarn ore body in Jiama deposit is mainly controlled by favorable metallogenic temperature, redox state, pH value, HS⁻ concentration and Fe²⁺ concentration.

Conclusions The redox state controls the proportion of calcium-iron garnet and calcium-aluminum garnet in skarn garnet, the favorable temperature, pH value and HS⁻ concentration control the precipitation of lead, zinc and molybdenum, and the precipitation of copper is closely related to the concentration of Fe²⁺.