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K-Pg extinction sum of multiple events?



From: Ben Creisler
bcreisler@gmail.com

A new online paper:

Thomas S. Tobin, Peter D. Ward, Eric J. Steig, Eduardo B. Olivero,
Isaac A. Hilburn, Ross N. Mitchell, Matthew R. Diamond, Timothy D.
Raub & Joseph L. Kirschvink (2012)
Extinction patterns, delta18O trends, and magnetostratigraphy from a
southern high-latitude Cretaceous – Paleogene section: Links with
Deccan volcanism.
Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication)
http://dx.doi.org/10.1016/j.palaeo.2012.06.029
http://www.sciencedirect.com/science/article/pii/S0031018212003847?v=s5


Although abundant evidence now exists for a massive bolide impact
coincident with the Cretaceous-Paleogene (K-Pg) mass extinction event
(~ 65.5 Ma), the relative importance of this impact as an extinction
mechanism is still the subject of debate. On Seymour Island, Antarctic
Peninsula, the López de Bertodano Formation yields one of the most
expanded K-Pg boundary sections known. Using a new chronology from
magnetostratigraphy, and isotopic data from carbonate-secreting
macrofauna, we present a high-resolution, high-latitude
paleotemperature record spanning this time interval. We find two
prominent warming events synchronous with the three main phases of
Deccan Traps flood volcanism, and the onset of the second is
contemporaneous with a local extinction that pre-dates the bolide
impact. What has been termed the K-Pg extinction is potentially the
sum of multiple, independent events, at least at high latitudes.