Abstract:
The Qianhe Gold Deposit is tectonically located on the northeastern margin of the Xiong’er Terrane along the southern margin of the North China Craton, where ore-forming geological conditions are favorable. Since its discovery in the 1980s, various genetic models have been proposed for the deposit, seriously constraining deep and peripheral exploration. To clarify the genesis of the deposit, this study systematically investigated fluid inclusions in quartz and trace elements of ore minerals from the Qianhe Gold Deposit. The results indicate that several types of fluid inclusions are developed in hydrothermal quartz from the deposit. Stage I quartz is dominated by W-type and C-type inclusions, with complete homogenization temperatures ranging from 268 °C to 365 °C. Stage II quartz contains C-type, W-type, and PC-type inclusions, among which W-type and PC-type inclusions commonly coexist, with complete homogenization temperatures of 205 °C–308 °C. Stage III quartz mainly contains W-type and C-type inclusions, with relatively lower complete homogenization temperatures of 184 °C–275 °C. Stage IV quartz contains only W-type inclusions, with complete homogenization temperatures ranging from 80 °C to 192 °C. The ore-forming fluids evolved from relatively high-temperature to medium- and low-temperature conditions, representing an medium- to low-temperature hydrothermal system overall. The chondrite-normalized rare earth element patterns and primitive mantle-normalized trace element spider diagrams of pyrite are similar to those of the associated intrusive rocks, which indicates that mineralization is closely related to intrusive activity. Comprehensive analysis suggests that the ore-forming fluids of the Qianhe Gold Deposit had characteristics of deep-sourced fluids, and that the mineralization process was likely influenced by magmatic activity. The ore-forming materials were closely related to the evolution of deep magmatic–crustal materials. Therefore, the Qianhe Gold Deposit is interpreted as a hydrothermal gold deposit formed through the combined action of tectonism, magmatism, and hydrothermal processes.