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Cretaceous-Paleogene Boundary asteroid impact and extinction timing



From: Ben Creisler
bcreisler@gmail.com


New in Science magazine:



Paul R. Renne, Alan L. Deino, Frederik J. Hilgen, Klaudia F. Kuiper,
Darren F. Mark, William S. Mitchell III, Leah E. Morgan, Roland
Mundil, and Jan Smit (2013)
Time Scales of Critical Events Around the Cretaceous-Paleogene Boundary.
Science 339(6120):. 684-687
DOI: 10.1126/science.1230492
http://www.sciencemag.org/content/339/6120/684.abstract


Mass extinctions manifest in Earth's geologic record were turning
points in biotic evolution. We present 40Ar/39Ar data that establish
synchrony between the Cretaceous-Paleogene boundary and associated
mass extinctions with the Chicxulub bolide impact to within 32,000
years. Perturbation of the atmospheric carbon cycle at the boundary
likely lasted less than 5000 years, exhibiting a recovery time scale
two to three orders of magnitude shorter than that of the major ocean
basins. Low-diversity mammalian fauna in the western Williston Basin
persisted for as little as 20,000 years after the impact. The
Chicxulub impact likely triggered a state shift of ecosystems already
under near-critical stress.