The relationship between stratabound Pb–Zn–Ag and porphyry–skarn Mo mineralization in the Laochang deposit, southwestern China: Constraints from pyrite Re-Os isotope, sulfur isotope, and trace element data

摘要: Abstract The Laochang polymetallic deposit is located in the Sanjiang Tethyan metallogenic province of southwestern China. This contains stratabound (and locally vein-type) Pb–Zn–Ag mineralization and underlying porphyry–skarn Mo mineralization. characterized by massive sulfide ores composed mainly pyrite, sphalerite, galena, minor chalcopyrite, whereas quartz–sulfide veins comprising molybdenite, sphalerite galena. age origin has long been debated, its relationship to remains unknown. Integrated pyrite Re-Os isotope, sulfur situ trace element data are used here constrain both types their genetic relationships. Pyrite related yields a isochron 47.3 ± 4.8 Ma, which consistent with previous molybdenite zircon U-Pb ages granite porphyry (~44–50 Ma). from failed yield geologically meaningful age, but associated galena have 308 ± 25 Ma (Liu et al., 2015), Carboniferous host basalts. Pyrite, chalcopyrite δ34S values (−2.1 0.5‰; average 0.48‰) indistinguishable those sulfides (−4 1.9‰; 0.52‰). Initial Os isotope ratios indicate crustal for calculated (Se/S)fluid Co/Ni mixed sedimentary hydrothermal origin, significant magmatic contribution. identification component, Eocene mineralization, phyllic propylitization alteration indicates that magmatic–hydrothermal component reflects overprinting volcanogenic fluids derived an porphyry.