Porphyry to Epithermal Transition in the Altar Cu-(Au-Mo) Deposit, Argentina, Studied by Cathodoluminescence, LA-ICP-MS, and Fluid Inclusion Analysis

The middle to late Miocene Altar porphyry Cu-(Au-Mo) deposit, located in the Andean Main Cordillera of San Juan Province (Argentina), is characterized by the superposition of multiple vein generations consisting of both porphyry-type and high sulfidation epithermal-style alteration and mineralization. We constrain the physical and chemical evolution of the hydrothermal fluids that formed this deposit based on description and distribution of vein types, scanning electron microscopy, cathodoluminescence (CL) imaging, trace elements in quartz veins, and fluid inclusion microthermometry.