Origin of the Bada porphyry Cu–Au deposit, eastern Tibet: Geology and isotope geochemistry (C–O–S–Pb) constraints

•The Cu–Au mineralization at Bada is mainly hosted by the quartz monzonite porphyry.•The Cu–Au orebodies occur within the potassic and phyllic alteration zones.•The C–O–S–Pb isotopic compositions indicate that ore-forming fluids and lead were originated principally from a magma source.•Bada is a newly discovered porphyry Cu–Au deposit in the Yulong porphyry Cu (–Mo–Au) belt.