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

The Laochang polymetallic deposit is located in the Sanjiang Tethyan metallogenic province of southwestern China. This deposit contains stratabound (and locally vein-type) Pb–Zn–Ag mineralization and underlying porphyry–skarn Mo mineralization. The stratabound Pb–Zn–Ag mineralization is characterized by massive sulfide ores composed mainly of pyrite, sphalerite, galena, and minor chalcopyrite, whereas the underlying porphyry–skarn Mo mineralization is characterized by quartz–sulfide veins comprising mainly pyrite, chalcopyrite, molybdenite, and minor sphalerite and galena. The age and origin of the stratabound Pb–Zn–Ag mineralization has long been debated, and its relationship to the porphyry–skarn Mo mineralization remains unknown. Integrated pyrite Re-Os isotope, sulfur isotope, and in situ trace element data are used here to constrain the age and origin of both types of mineralization and their genetic relationships.