Fluid inclusions and U/Pb dating of the El Pilote Fluorite skarn occurrence: Metallogenic implications

The “El Pilote” deposit, located in the Coahuila State (NE Mexico), is a small fluorite-bearing calcic skarn we dated at 28.4 ± 0.4 Ma (U/Pb). Fluid inclusion studies, performed on fluorite, indicate the occurrence of hot, hypersaline fluids, trapped during the prograde stage. The retrograde fluids present progressively lower temperatures and salinities. All this fluid data depicts a coherent scenario where early magmatic-dominated fluids were progressively mixed up with low-temperature, low-salinity meteoric fluids whose predominance indicates the waning of the hydrothermal system.