In-situ geochemical and sulfur isotope signature of pyrite: Constraints on ore-forming processes of the Qulong Cu-Mo deposit, Tibet

•Pyrite-bearing veins at Qulong can be divided into seven subclasses.•The contents of Co and Ni and the ratios of Co/Ni and Ni/Se in pyrite can be used to investigate the evolution of fluid composition, temperature and oxygen fugacity.•Changes in trace elements and S isotopes in pyrite can be used to investigate the evolution of magmatic-hydrothermal fluids.