Reworked K/Pg ejecta in early Paleocene deposits, Difunta Group, NE Mexico
Ejecta del K/Pg retrabajados en depósitos del Paleoceno temprano, Grupo Difunta, NE de México
David Cadena-González1, Ricardo Barragán2, Francisco A. Vega-Sandoval3, Criseida Ruiz-Aguilar4, Francisco J. Vega2,*
1 Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Unidad de Posgrado, Edificio D primer piso, Ciudad Universitaria, 04510, CDMX, México.
2 Instituto de Geología, Universidad Nacional Autónoma de México, Circuito de la Investigación Científica, Ciudad Universitaria, 04510, CDMX, México.
3 Facultad de Ciencias, Universidad Nacional Autónoma de México, Circuito de la Investigación Científica, Ciudad Universitaria, 04510, CDMX, México.
4 Escuela Nacional de Estudios Superiores, Unidad Juriquilla, Universidad Nacional Autónoma de México, Bulevar Juriquilla 3001, 76230, Juriquilla, Querétaro, México.
Corresponding author: (F.J. Vega) This email address is being protected from spambots. You need JavaScript enabled to view it.
How to cite this article:
Cadena-González, D., Barragán, R., Vega-Sandoval, F.A., Ruiz-Aguilar, C., Vega F.J., 2025, Reworked K/Pg ejecta in early Paleocene deposits, Difunta Group, NE Mexico: Boletín de la Sociedad Geológica Mexicana, 77(2), A190625. http://dx.doi.org/10.18268/BSGM2025v77n2a190625
Manuscript received: June 9, 2025; Corrected manuscript received: June 11, 2025; Manuscript accepted: June 20, 2025
ABSTRACT
The Chicxulub impact triggered massive sediment removal and deposit of ejecta around the world. The impact must also have triggered large tsunamis, whose geological record is nevertheless scarce. Some of the tsunamite backwash deposits were reworked during early Paleocene, and evidence of severe earthquakes and ejecta fall are preserved along the tsunamite deposits at top of Cretaceous and the base of lower Paleocene sediments in the Difunta Group, within Parras and La Popa basins, NE Mexico. Tsunamite backwash deposits were previously studied near El Papalote diapir (La Popa Basin, Nuevo León), where pseudotektites and bioclasts are ubiquitously abundant, along with diverse bioclasts and intraclasts of different lithologies that include igneous, metamorphic and sedimentary rocks from outcrops located to the N of the Difunta Group. We report here on three localities with lower Paleocene tempestites at La Popa Basin, all interpreted as storm deposits. These outcrops are found at the top of the K/Pg Delgado Sandstone Member and also include altered pseudotektites and bioclasts. Although ejecta and bioclasts were already reported from two localities (El Papalote and Amargos), we also illustrate deformed quartz and uncommon bioclasts such as crab cuticle, ammonite nuclei and shark teeth.
Keywords: K/Pg, tsunamite, tempestites, ejecta, bioclasts, Difunta Group.
