Wall‐rock Alteration and Element Fluxes in the Disuga Porphyry Cu Deposit, Northwest Yunnan Province, China, and Implications for Mineral Exploration

Abstract The Disuga Cu deposit, located in the eastern porphyry belt of the Zhongdian arc, southwest China, provides a window into magmatic–hydrothermal processes controlling porphyry Cu mineralization. Based on zircon U‐Pb geochronology, hydrothermal mineral chemistry, short‐wave infrared spectroscopy, and mass balance modeling, this study investigated the alteration zonation and element mobility in the Disuga Cu deposit. Zircon U‐Pb ages of the ore‐hosting quartz dioritic porphyries (222.4 ± 3.1 and 219.3 ± 2.4 Ma) are similar to those of Late Triassic subduction‐related magmatism. High zircon‐crystallization temperatures (727 ± 26°C) and elevated oxygen fugacity (ΔFMQ + 2.0) confirm these porphyries were favorable for mineralization. Hydrothermal sericite (Si = 6.49 atoms per formula unit [apfu]; Al VI = 3.39 apfu) and chlorite (Fe/(Fe + Mg) = 0.59–0.63) compositions indicate an acidic reduced fluid. Three distinct hydrothermal stages were identified: (1) phyllic alteration (370°C); (2) propylitic alteration (315°C); and (3) low‐temperature hydrothermal alteration (242°C). Mass balance calculations show that the Cu migration rate (155.6%/114.4%) in the propylitic/phyllic alteration zones was higher than that of Mo (14.3%; limited to the propylitic alteration zone). The alteration mineralization assemblages indicate the occurrence of deep potassic alteration zones and porphyry Cu‐(Mo) mineralization in the Disuga area.