Geochemical discrimination between fertile and barren Eocene potassic porphyries in the Jinshajiang Cu–Au–Mo metallogenic belt, SW China: implications for petrogenesis and metallogeny

Abstract The Jinshajiang potassic porphyry metallogenic belt represents one of the most important Chinese intrusive belts that hosts Eocene Cu–Au–Mo porphyry systems including the Narigongma Mo, Yulong Cu, and Beiya Au deposits. This metallogenic belt also contains several uneconomic potassic intrusions, such as the Jianchuan, Shigu and Binchuan granite porphyries. Bulk-rock geochemical compositions together with Sr–Nd–Pb isotope ratios, and zircon Hf isotope and trace element compositions are compiled and interpreted to reveal the fundamental differences leading to the different fertility of these potassic porphyries at Jinshajiang. The economic Narigongma, Yulong, Beiya, and barren Jianchuan, Binchuan, Shigu granite porphyries are all formed in the same post–collisional tectonic setting, and all exhibit high SiO2 (61 – 65 wt.%), and total alkali contents (K2O + Na2O > 8 wt.%). Based on low Ce contents (