Geologic setting of the Pueblo Viejo Au–Ag–Cu-(Zn) mining district, Dominican Republic - Links to volcanic domes and volcanogenic massive sulfide mineralization

• Published in: Journal of South American earth sciences Vol. 123; p. 104158
• Main Authors: Nelson, Carl E., Dominguez, Hugo, Leonardo A., Rene, Polanco, Jose, Carrasco C., Carlos
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2023
• Subjects: Epithermal deposits; Lithocaps; Los Ranchos formation; Maimón formation; Porphyry deposits; Pueblo Viejo mine; VMS deposits; Volcanic domes; Pueblo Viejo mine; Volcanic domes; Los Ranchos formation; Maimón formation; VMS deposits; Porphyry deposits; Epithermal deposits; Lithocaps
• ISSN: 0895-9811; 1873-0647
• DOI: 10.1016/j.jsames.2022.104158

Geologic mapping at the Pueblo Viejo Au–Ag–Cu-(Zn) mine, Dominican Republic, and across the surrounding Pueblo Viejo district, reveals the geologic setting at the time of mineralization. Ore deposits consisting of disseminated sulfide, bedded massive sulfide, and high-grade massive sulfide veins formed (∼112 Ma) in a volcanic dome field during a period of extension across an emergent, intraoceanic island arc. Geologic maps reveal the links between volcanic domes and structure, hydrothermal alteration and mineralization, and ore deposits and gossans. Whole-rock geochemical data establish a tholeiitic signature for Early Cretaceous magmatism including the volcanic dome field. Northerly-striking, high-angle faults controlled the emplacement of volcanic domes and served as feeders for hydrothermal solutions. The largest ore deposits formed in a subsiding, marginal marine, volcano-sedimentary basin. Stacked intervals of bedded massive sulfide mineralization indicate that the basin was subsiding while mineralization was underway. Calc-alkaline dikes and plutons in the Pueblo Viejo district intruded at ∼88 Ma, well after mineralization had ended. Low-angle reverse faulting, greenschist facies metamorphism, and milky quartz veining and replacement were also Late Cretaceous (post-mineral) events. Ore deposits in the Pueblo Viejo district are best described as hybrid epithermal – VMS deposits, formed during a period of Early Cretaceous extension, tholeiitic volcanism, and volcanic dome emplacement in a shallow, marginal marine environment. Exploration for Au–Ag–Cu-(Zn) deposits like Pueblo Viejo should focus on intraoceanic island arcs, tholeiitic volcanic dome fields, extensional volcano-sedimentary basins, and VMS mineral occurrences. •Au–Ag–Cu-(Zn) ore deposits formed at volcanic dome margins.•Ore consists of disseminated sulfide, massive sulfide veins, and massive sulfide beds.•The deposits formed at shallow depth in a marginal marine environment.•Mineralization occurred during extension across an intraoceanic island arc.•The magmatic-hydrothermal system was tholeiitic in composition.