Resumen de Modelos de extinción de foraminíferos planctónicos en el límite Cretácico/Terciario (K/T) de El Mulato (México) y Agost (España)
José Antonio Arz Sola, Ignacio Arenillas Sierra, José Guadalupe López Oliva, Eustoquio Molina Martínez
The Cretaceous/Tertiary Boundary (K/T) is still a controversial case in the history of the Earth. This boundary has been one of the most investigated subject during the last 17 years, trying to find clues to better understand the event (s), that culminated with the disappearance of several groups of organisms including dinosaurs and planktic foraminifera. Data from El Mulato in NE Mexico and Agdst (Spain) in the western Tethys may'support respectively both theories; a gradual disappearance and amassive catastrophic instantaneous extinction of organisms 65 M a. ago. Comparison of data shows that at El Mulatd the sudden disappearance of Cretaceous planktic foraminifera and the simultaneous first appearance of tertiary species indicates a hiatus at exactly the K/T boundary transition, superposed by a gradual extinction pattern associated to several events. At Agost a catastrophic instantaneous mass extinction is indicated at the K/T boundary This extinction pattern may be related to the impact of a celestial body that caused an extinction, one of the most important during the development of life
