The evolution of ore-forming fluids in the Lizigou gold deposit, Henan Province

Abstract：Located in Xiongershan metamorphic core complex of Henan Province, the Lizigou gold deposit has such mineralization types as Au, Ag and Pb (Ag) and shows considerable exploration potential. An analysis of fluid inclusions has revealed that there exist different types and combinations of inclusions at different ore-forming stages. At the early ore-forming stage (Ⅰ), the fluids were characterized by high temperature and high salinity, suggesting that they might have come from the depth; at the main ore-forming stage (Ⅱ), the temperature of the fluids dropped, and the salinity was relatively low but varied in a wide range (from 18.14 to 0.59 wt%); at the late ore-forming stage (Ⅲ), the ore-forming fluids further evolved, and the temperature and salinity decreased. Hydrogen and oxygen isotope data show that δD values of the ore-forming fluids at the early ore-forming stage varied in the range of -77.85 ‰- -70.43 ‰, implying that they were derived from hydrothermal and magmatic hydrothermal solutions; at Stage II and Stage III, the fluids obviously deviated from magma water and drifted towards atmospheric water in composition.