Ore-formation at the Halasheng Ag-Pb-Zn deposit, northeast Inner Mongolia as revealed by trace-element and sulfur isotope compositions of ore-related sulfides

•Halasheng Ag-Pb-Zn ores comprise skarns and intermediate sulfidation epithermal veins.•Sulfide trace elements and δ34S of ore sulfides support a magmatic-hydrothermal relationship.•Three generations of sphalerites with complex textures indicate temporal fluid evolution.•There is strong enrichment of Ag in sphalerite and Ag sulfosalts late in mineralization.•There is exploration potential for a district-scale porphyry mineral system at Halasheng.