Bioestratigrafía y reconstrucción paleoambiental del tránsito Cretácico-Paleógeno en El Mimbral (México)
- L. Alegret 1
- I. Arenillas 2
- Jose A. Arz 2
- E. Molina 2
- 1 Dept. Earth Sciences, University College London
- 2 Dpto. Ciencias de la Tierra, Universidad de Zaragoza
ISSN: 1576-5172
Year of publication: 2004
Issue Title: VI CONGRESO GEOLÓGICO DE ESPAÑA (Zaragoza, 12-15 julio, 2004)
Issue: 6
Pages: 357-360
Type: Article
More publications in: Geotemas (Madrid)
Abstract
Upper Cretaceous and Lower Paleogene benthic and planktic foraminifera from the El Minibral section (Mexico) were analysed in order to infer the biostratigraphy and the paleoenvironmental turnover across the Cretaceous/Paleogene (K/Pg) boundary. In the El Mimbral section, the UpperCretaceous marly Méndez and the Lower Paleogene marly Velasco Formations are separated by a0.5 to ~3 m-thick-Clastic Unit. We studied the upper 2 m of the Méndez Formation and the lowermost 3 m of the Velasco Formation, comprising the upper Maastrichtian A. mayaroensis and P.hantkeninoides Biozones, and the lower Danian G. cretacea and Pv. eugubina Biozones, respectively. Planktic foraminifera were affected by a catastrophic extinction at the K/Pg boundary, whereas benthic foraminifera show reorganization of the community structure rather than significantextinction. The benthic foraminiferal turnover may have resulted from the drop in primary productivity after the asteroid impact at the K/Pg boundary.