A Permian intermediate-sulfidation epithermal Pb-Zn-Ag deposit in the northern margin of North China Craton

Recent Pb-Zn-Ag exploration in the northern margin of North China Craton has made significant new discov-eries. Here we report one Pb-Zn-Ag deposit in the Shaolanghe orefield with typical signatures of intermediate-sulfidation epithermal deposits. Zhangjiagou Pb-Zn-Ag mineralization occurs within the Early Permian quartz diorite and Late Permian andesite. Three mineralization stages were identified: white quartz--rhodochrosite-sulfide Pb-Zn-mineralization stage (I), smoky quartz-sulfide Pb-Zn-Ag-mineralization stage (II), and calcite-quartz non-mineralization stage (III). Four sphalerite samples yield the Rb-Sr age of 265.3 Ma, indicating that Pb-Zn-Ag mineralization was associated with the Late Permian andesite. The liquid-rich fluid inclusions of Stage I show low-medium temperatures of 190-270 degrees C and low salinities (1-3 wt%), and those of Stage III are slightly lower (190-250 degrees C, 0.5-2 wt%), suggesting a low-salinity, low-temperature H2O-NaCl fluid system for the Zhangjiagou deposit. The H-O-C isotopic signatures indicate a mixed fluid of magmatic water with meteoric water. S and Pb isotopes suggest magmatic source for Zhangjiagou Pb-Zn-Ag mineralization, most likely shallow hydrous intermediate magma. Collectively, these geological, geochronological, and geochemical features indicate that Zhangjiagou is an intermediate-sulfidation epithermal Pb-Zn-Ag deposit.