Cretaceous-Paleogene boundary impact winter superimposed on long-term climate changes

Friday, 19 December 2014: 4:15 PM
Johan Vellekoop1, Jan Smit2, Appy Sluijs3, Henk Brinkhuis1,4, Selen Esmeray-Senlet5, Bas van de Schootbrugge1, James V Browning5, Kenneth G Miller5 and Jaap Sinninghe Damsté,4, (1)Utrecht University, Utrecht, Netherlands, (2)VU University Amsterdam, Amsterdam, Netherlands, (3)Utrecht University, Utrecht, 3584, Netherlands, (4)Royal Netherlands Institute for Sea Research, Den Burg, Netherlands, (5)Rutgers University, Piscataway, NJ, United States
It has become widely acknowledged that the Cretaceous – Paleogene (K-Pg) boundary mass extinction (~66Ma) is related to the environmental consequences of an impact of a large extraterrestrial body. This impact likely invoked exceptionally rapid and profound global climate change, which occurred superimposed on ongoing, long-term environmental changes. The interplay between impact-related and long-term environmental changes is still poorly documented. In a recent study, we showed that a TEX86 based Sea Surface Temperature (SST) K-Pg record from Brazos River (USA) indeed shows evidence for rapid short-term cooling following the K-Pg impact. This confirmed for the first time the hypothesis of a so-called ‘impact winter’ invoked by dust and aerosols produced by the impact, blocking incoming solar radiation.

This short-lived cold phase has so far not been confirmed by other studies. To verify the record from Brazos River and to reveal ongoing, long-term climate change, we performed a high resolution marine palynological and organic geochemical study on four stratigraphically expanded cores from the New Jersey Shelf, eastern USA, spanning the K-Pg boundary, using the TEX86 sea surface temperature (SST) proxy. Indeed, our new composite record confirms the brief cooler episode immediately following the K-Pg impact. Here we present these impact-related sea surface temperature changes in the context of the long term climate changes across the K-Pg boundary interval.