Resumen de Foraminíferos planctónicos y bentónicos del límite Cretácico/Terciario de Aín Settara, Tunicia: dos patrones de extincióndiferentes y una misma causa
Ignacio Arenillas Sierra, Laia Alegret Badiola, José Antonio Arz Sola, Eustoquio Molina Martínez
A detailed biostratigraphic and quantitative study based on foraminifera from the Ain Settarasection (Tunisia) allows us to infer two different extinction patterns in planktic and benthicforaminifera across the Cretaceous/Tertiary (K/T) boundary. More than 68% (and probably 97%)of the Maastrichtian planktic foraminifera! species, whereas only 21% of Maastricht!an benthicforaminiferaI species, became extinct in coincidence with the K/T boundary and the impact evidence. However, more than 51% of the benthic foraminifera! species suffer a Lazaro effect inthe lower most Danian, and infaunal benthic morphogroups drastically dropped just at the K/Tboundary, indicating a sudden breakdown of the food supply. Planktic foraminifera! catastrophic mass extinction and P/B ratio drop indicate a sudden decrease of the superficial-marine productivity. All these data suggest that the K/T foraminiferaI turn overs were linked with anasteroid impact.
