Resumen

MARTIN-RAYELO, Andrés Sebastián  y  ROMERO-ORDONEZ, Fernando Elí. Petrography of the Consorcio rocks from the Cunas emerald mine (Maripi, Boyaca). Stratigraphic relationship with Medium Magdalena Basin rocks (Colombia). Bol. geol. [online]. 2022, vol.44, n.2, pp.125-143.  Epub 18-Jul-2022. ISSN 0120-0283.  https://doi.org/10.18273/revbol.v44n2-2022006.

The Western Emerald Belt (WEB) and the Middle Magdalena Basin (MMB) are two Colombian regions characterized to have large quantity of mineral resources. The study of an emerald deposit in WEB corresponding to the Cunas emerald mine in Maripí (Boyacá) with field work, rock and mineral sampling, stratigraphic sections uplift, petrography, and complementary micro-Raman spectroscopy shows that the rocks in the Furatena and Muzo formations share a common depositional, diagenetic, and lithofacies history with Paja Formation from the MMB, comprising great thickness, calcareous mudstones of proximal deep marine facies, accumulated during the Early Cretaceous Period (Hauterivian-Barremian) in a continual regional basin affected by rifting. In the WEB, the emerald mineralizations hosted in the Muzo Formation are related to hydrothermal and tectonic processes that can be summarized in five mineralizing stages in a paragenetic sequence, being controlled by the mineralogy and geochemistry of the host rocks. These stages are as follows: premineral, albitization, two carbonatization stages, and a post-mineral or alteration stage; recognized by contrasting shear relationships and paragenesis. A preliminary stratigraphical correlation proposal is presented among the Consorcio stratigraphic section studied in the present work, with other WEB and MMB sections studied by other authors, using facies and sequence stratigraphic analysis. Muzo Formation preserve lagoon facies affected by storms, the Muzo's thickness greater than in Consorcio regarding its type section is given by paleobathymetry and tectonic inversion history of grabens and half-grabens; equally in this point the basin could be closest to the coastline respect to MMB during Early Cretaceous.

Palabras clave : Western Emerald Belt; Maripí mining district; Sequence stratigraphy; Lagoon facies; Paragenetic sequence; Transgressive surface.

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