Recuperación de la productividad primaria en el área del Tethys tras el evento del límite Cretácico/Terciario

• Autores: Laia Alegret Badiola, Ignacio Arenillas Sierra, José Antonio Arz Sola, Eustoquio Molina Martínez
• Localización: Geotemas (Madrid), ISSN 1576-5172, Nº. 5, 2003 (Ejemplar dedicado a: V Congreso del Grupo Español del Terciario (Granada, 23-25 de septiembre, 2003)), págs. 27-30
• Idioma: inglés
• Enlaces
  • Texto Completo Ejemplar
• Resumen

  • We studied Upper Cretaceous and lower Paleogene foraminifera in three sections from the Tethyan area, the Spanish upper to middle bathyal Agost section, and the tunisian outer shelf-upper bathyal El Kef and Ain Settara sections, in order to infer the paleoenvironmental turnover across the Cretaceous-Tertiary transition. Whereas planktic foraminifera suffered a catastrophic mass extinction in coincidence with the Cretacesous/Tertiary boundary, benthic foraminifera show a dramatic change in the structure of their assemblages. At the level of extinction of planktic assemblages and enrichment in Ir and other geochemical anomalies, highly diversified, low-dominance upper Maastrichtian assemblages with infaunal and epifaunal morphogroups were suddenly replaced by taxonomically impoverished assemblages, strongly dominated by epifaunal morphogroups. Several opportunistic taxa have short peaks in relative abundance, possibly reflecting environmental instability, with benthos receiving food from local blooms of primary producers.

    Infaunal groups did not recover to pre-extinction relative abundances, indicating that the food supply to the benthos did not recover fully over the studied interval. The benthic foraminiferal faunal changes are compatible with the effects of an asteroid impact, which severely destabilized primary producers and the oceanic food-web.