title: Time scales of critical events around the Cretaceous-Paleogene boundary.
abstract: Mass extinctions manifest in Earth's geologic record were turning points in biotic evolution. We present (40)Ar/(39)Ar 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.
authors: Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, CA 94709, USA. prenne@bgc.org
authors: Paul R
authors: PR
authors: Renne
authors: Alan L
authors: AL
authors: Deino
authors: Frederik J
authors: FJ
authors: Hilgen
authors: Klaudia F
authors: KF
authors: Kuiper
authors: Darren F
authors: DF
authors: Mark
authors: William S
authors: WS
authors: Mitchell
authors: Leah E
authors: LE
authors: Morgan
authors: Roland
authors: R
authors: Mundil
authors: Jan
authors: J
authors: Smit
mesh_terms: D000818:Animals; D001128:Argon; D002910:Chronology as Topic; D017753:Ecosystem; D053476:Extinction, Biological; D019015:Geologic Sediments; D008322:Mammals; D008800:Mexico; D018543:Minor Planets; D011868:Radioisotopes; D055110:Radiometric Dating
chemical_list: D011868:Radioisotopes; D001128:Argon