Geology and Mineral Assemblage of Tertiary Skarn Cu-Auplus/minus Mo Deposits in the Southeastern Gangdese Arc: Implications for Deep Exploration

Medium-and large-scaled skarn Cu-Au +/-Mo deposits, e. g. Kelu, Liebu, Chongmuda and Chenba etc., are distributed in Shannan area of the Gangdese Cu-Au metallogenic belt. Intrusions-related skarn copper mineralization belongs to high K and calc-alkalic rock series, located in late collision volcano-magmatic arc and formed between 20 to 30Ma. Copper mineralization occurs at exocontact zone of the lower Cretaceous Bima Group carbonate and other calcareous-bearing sedimentary rocks with intrusions. At present, three main mineralization types are identified, including skarn type, hydrothermal vein type, and porphyry type. Mineralizing associations are Cu-Mo, Cu-Au, and Cu. In ore districts, those mineralization types form an entire porphyry-skarn Cu-Auplus/minus Mo ore forming system. Alterations of the exocontact are mainly skarnization and hornfielsization, while the alterations of the endocontact are mainly sericitization, silification and chloritization of intrusion. In the study area, the endoskarn is not we