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Boletín de la Sociedad Geológica Mexicana Volumen 72, núm. 3, A011119, 2020 |
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The Hatillo Limestone, Pueblo Viejo district, Dominican Republic: Marginal reef or impermeable cap?
La Caliza Hatillo, distrito de Pueblo Viejo, República Dominicana: ¿Un arrecife marginal o
capa impermeable?
Carl Nelson1,*, José Polanco2, Arturo Macassi2, Hugo Dominguez3, Joaquín Proenza4,
Lisard Torró5, David Rhys6, Manuel Iturralde-Vinent7
1 Recursos del Caribe, S.A., 2360 23rd Street Boulder, 80304, Colorado, United States.
2 Pueblo Viejo Dominicano Corp., Av. Lope de Vega No. 29, 10125, Santo Domingo, Dominican Republic.
3 Barrick International Ltd., Av. Lope de Vega No. 29, Santo Domingo 10125, Dominican Republic.
4 Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciencias de la Tierra, Universitat de Barcelona, 08028, Barcelona, Spain.
5 Geological Engineering Program, Faculty of Sciences and Engineering, Pontifical Catholic University of Peru, 15088, Lima, Peru.
6 Panterra GeoServices Inc., 14180 Greencrest Drive, Surrey, B.C., V4P 1L9, Canada.
7 Academia de Ciencias de Cuba, No.460 entre Amargura y Teniente Rey, Habana Vieja, 259, La Habana, Cuba.
* Corresponding author: (C. Nelson) This email address is being protected from spambots. You need JavaScript enabled to view it.
How to cite this article:
Nelson, C., Polanco, J., Macassi, A., Dominguez,H., Proenza, J., Torró, L., Rhys, D., Iturralde-Vinent, M., 2020, The Hatillo Limestone, Pueblo Viejo district, Dominican Republic: Marginal reef or impermeable cap?: Boletín de la Sociedad Geológica Mexicana, 72 (3), A011119. http://dx.doi.org/10.18268/BSGM2020v72n3a011119
Abstract
The Hatillo Limestone and the underlying Los Ranchos Formation are exposed over an east-west distance of 100 km in the eastern Dominican Republic. The lowermost portion of the Hatillo Limestone in the Pueblo Viejo district contains a Late Lower Albian fossil assemblage including corals and rudist bivalves indicative of a near-shore reef environment. Diamond drilling in the Pueblo Viejo district and exposures in the open pits show that the Hatillo Limestone conformably overlies the Early Cretaceous Los Ranchos Formation. Volcanogenic massive sulfide beds, exposed in the Moore pit, provide evidence for an Early Cretaceous, syn-mineralization paleosurface. Altered and mineralized clasts in the epiclastic, sedimentary host-rock section at the Pueblo Viejo mine indicate that the ore deposits were open to erosion during hydrothermal alteration and mineralization. The Hatillo Limestone did not overlie the ore deposits during the mineralizing event and, consequently, could not have acted as an impermeable cap to ascending hydrothermal fluids. Intra-oceanic island arc volcanism (Los Ranchos Formation) overlapped at the Aptian–Albian boundary (112 Ma) with a marginal fringing reef (basal Hatillo Limestone). The marginal reef gradually gave way to deeper-water facies as Hatillo Limestone deposition progressed through the middle Albian. Low-angle reverse faulting, penetrative deformation, and metamorphic recrystallization affected the Hatillo Limestone as well as the Los Ranchos and Maimón formations during the Late Cretaceous. Deformation intensity and metamorphic grade progressed from incipient metamorphism in the Pueblo Viejo district to schists in the Maimón Formation to amphibolite near a faulted contact with the Loma Caribe peridotite.
Keywords: Caribbean tectonics, Early Cretaceous unconformity, Los Ranchos Formation, Cretaceous metamorphism, arc polarity reversal.
