The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundary

Abstract

International audienc

Dinosaur morphological diversity and the end-Cretaceous extinction

“…F ew issues in the history of palaeontology have fuelled as much research and popular fascination as the extinction of non-avian dinosaurs at the end of the Cretaceous (65.5 Myr ago) [1][2][3] . Despite 30 years of intensive research, a fundamental question remains: were dinosaurs undergoing a long-term decline before intensive volcanism and the Chicxulub bolide impact in the latest Cretaceous, or did these contingencies of Earth history strike down dinosaurs during or near their prime (at a time when their global biodiversity was stable or even increasing) [3][4][5][6][7][8][9][10][11][12][13][14][15] ?…”

Last occurrence of Abathomphalus mayaroensis (Bolli) foraminiferid index of the Cretaceous–Paleogene boundary: the calcareous nannofossil proof

“…Similarly, the Lower Paleocene foraminiferid assemblages also comprise reworked and survivor taxa (Huber 1996;Gallala et al 2009;Slimani & Toufiq 2013). Moreover, the post-extinction Paleogene recovery of planktonic foraminiferids was polyphasic and began thousands of years after the terminal event (Coxall et al 2006;Gallala et al 2009;Schulte et al 2010). The increase in abundance (bloom) of survivor or disaster opportunistic taxa, such as the planktonic foraminiferids Guembelitria cretacea, Hedbergella holmdelensis, or H. monmouthensis (Pardo & Keller 2008;Slimani & Toufiq 2013), and the calcareous nannoplankton Braarudosphaera spp.…”

“…Many taxa from different groups of both land and marine organisms suffered a mass extinction in consequence of the K/Pg boundary event (see D'Hondt 2005;Schulte et al 2010 for review), but not necessarily precisely at the time of the K/Pg boundary event and there are connections with paleolatitude (Keller 2001;Keller et al 2007). Therefore, highresolution determination of the boundary based on them is suspicious.…”

Mesozoic ecosystems – climate and biotas

“…The study further reveals that plants responded to significant changes in pCO 2 across the K-Pg by changing the stomatal density of their leaves. The Cretaceous ended with an asteroid impact that caused widespread ecological disruption, culminating in major, but seemingly targeted, extinctions (Schulte et al, 2010). These extinctions (non-avian dinosaurs for example) cleared the way for the modern world.…”