Paragenesis, hydrothermal alteration, and geochemistry of multiple stages of hydrothermal mineralization at the Pierina Gold Deposit, northern Peru

Pierina is a high-sulfidation, volcanic hosted, epithermal, gold-silver deposit, located in the Cordillera Negra of the Ancash Province, northern Peru. Gold and silver ores are hosted in early Miocene andesites and dacites. Precious-metal mineralization involved several stages of intense hydrothermal alteration and oxidation mainly in the dacite tuffs at about 14.4 Ma. Fluid movement was strongly controlled by parallel to sub-parallel, high-angle faults/fractures.; There were six episodes of hydrothermal activity: (1) early quartz-alunite +/- hematite-pyrite alteration; (2) formation of vuggy silica rock by alunite-destructive solutions; (3) deposition of pyrite with Cu, As, +/-Au; (4) deposition of native sulfur; (5) extensive hypogene oxidation and leaching; and (6) deposition of acanthite + barite + gold.