Australia: The Land Where Time Began

A biography of the Australian continent 

Mass Extinction Event - the Chicxulub Asteroid Impact at the Cretaceous-Palaeogene Boundary

At 65.5 Ma one of the 3 largest mass extinction events occurred in the past 500 My at the Cretaceous-Palaeogene boundary. According to the authors¹ this extinction event coincided with the Chicxulub Impact in Mexico and within the time span of the Deccan Traps flood basalt volcanism in India. In this study the authors¹ synthesised the global stratigraphy across this boundary to assess the causes that have been proposed for the mass extinction events, saying a single deposit, that is ejecta-rich, is globally distributed at the Cretaceous-Palaeogene boundary, is compositionally linked to the Chicxulub impact. According to the authors¹ they were led to the conclusion that the Chicxulub impact trigged the mass extinction by the temporal match between the layer of ejecta and the onset of the extinctions, as well as the agreement of the ecological patterns found in the fossil record with environmental perturbations that have been modelled, such as darkness and cooling.

Sources & Further reading

1. Schulte, Peter, Laia Alegret, Ignacio Arenillas, José A. Arz, Penny J. Barton, Paul R. Bown, Timothy J. Bralower, et al. "The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundary." Science 327, no. 5970 (March 5, 2010 2010): 1214-18.