No abstract

No abstract

No abstract

No abstract

Hydrothermal alteration and mineralization at the Wunugetu porphyry Cu-Mo deposit, China, include four stages, i.e., the early stage characterized by quartz, K-feldspar and minor mineralization, followed by a molybdenum mineralization stage associated with potassic alteration, copper mineralization associated with sericitization, and the last Pb-Zn mineralization stage associated with carbonation. Hydrothermal quartz contains three types of fluid inclusions, namely aqueous (W-type), daughter mineral-bearing (S-type) and CO 2 -rich (C-type) inclusion, with the latter two types absent in the late stage. Fluid inclusions in the early stage display homogenization temperatures above 510°C, with salinities up to 75.8 wt.% NaCl equivalent. The presence of S-type inclusions containing anhydrite and hematite daughter minerals and C-type inclusions indicates an oxidizing, CO 2 -bearing environment. Fluid inclusions in the Mo-and Cu-mineralization stages yield homogenization temperatures of 342-508°C and 241-336°C, and salinities of 8.6-49.4 and 6.3-35.7 wt.% NaCl equivalent, respectively. The presence of chalcopyrite instead of hematite and anhydrite daughter minerals in S-type inclusions indicates a decreasing of oxygen fugacity. In the late stage, fluid inclusions yield homogenization temperatures of 115-234°C and salinities lower than 12.4 wt.% NaCl equivalent. It is concluded that the early stage fluids were CO 2 bearing, magmatic in origin, and characterized by high temperature, high salinity, and high oxygen fugacity. Phase separation occurred during the Mo-and Cu-mineralization stages, resulting in CO 2 release, oxygen fugacity decrease and rapid precipitation of sulfides. The late-stage fluids were meteoric in origin and characterized by low temperature, low salinity, and CO 2 poor.