Facies analysis, stratigraphic architecture and depositional environments of the Guanajuato conglomerate in the Sierra de Guanajuato, Mexico

The Guanajuato conglomerate, spanning over 2000 meters in thickness and extending more than 100 kilometers, reveals the sedimentary history of post-Laramide extensional basins in Mexico's Central Plateau. This study identifies two distinct members within the conglomerate: a lower member characterized by fluvial braided systems, featuring coarse-grained deposits, lava flows, and debris flows; and an upper member dominated by alluvial fan environments with clast-supported conglomerates and fine-grained sediments. Facies analysis across nine localities uncovered 14 facies types, including traction-dominated conglomerates, hyperconcentrated flow deposits, and desiccation cracks, providing insights into the depositional dynamics of Cenozoic sedimentary systems. The research combines stratigraphic architecture with sedimentological observations to reconstruct paleoenvironments, offering a detailed model for understanding the evolution of extensional basins in this UNESCO World Heritage Site.

Puy-Alquiza, M. J., Miranda-Avilés, R., García-Barragán, J. C., Loza-Aguirre, I., Li, Y., & Zanor, G. A. (2017). Facies analysis, stratigraphic architecture and depositional environments of the Guanajuato conglomerate in the Sierra de Guanajuato, Mexico. Boletín de La Sociedad Geológica Mexicana, 69(2), 385–408. https://doi.org/10.18268/bsgm2017v69n2a5