Patterns and causes of mass extinction at the K/Pg boundary: Planktonic foraminifera from the North African Plate

Abstract

By far the most interest and attention has been focused on the great extinction that ended the Mesozoic. The obvious reason is that this event wiped out the dinosaurs. A second reason is the evidence of an extraterrestrial bolide impact (See Prothero 1998). For a long period of time causes and patterns of mass extinction at the K/Pg boundary received conflicting results. Some assigned this mass extinction to catastrophic effects, and some others referred to gradual environmental and climatic changes. However, since Molina et al. (1996) concluded that there were multiple causes to this mass extinction, the search in the subject became more reliable and accurate (e.g. Keller 2003; Macleod in press). Molina et al. (1996) stated that the catastrophic pattern of extinction at the K/Pg boundary is very compatible with the effect of a large meteorite impact, whereas the gradual and extended pattern of extinction across the Maastrichtian-Danian transition is compatible with temperature and sea level changes that may be related to massive volcanism. Keller (2003) argued that the unequivocal connection between intense volcanism and high stress assemblages during the late Maastrichtian to early Danian, and the evidence of multiple impacts, necessitates revision of current impact and mass extinction theories. Macleod (in press) cued that three prominent single-cause mechanisms have been popular in accounting for the K/Pg mass extinction, including sea-level change, a large igneous province volcanic eruption on what is now the Indian sub-continent, and the impact of a ~10 km bolide on Mexico's Yucatan Peninsula. He added that the ecological complexity of the end-Cretaceous extinctions, the time over which they took place, and the record of historical association between these mechanisms and extinctions over the last 250 m.y. suggests that no single mechanism can reasonably account for the patterns seen in the fossil record unless that record is assumed to be so strongly biased that the basis for recognizing the Maastrichtian as a time of widespread extinction is itself called into question. On the other hand, Twitchett (2006) contradicted the supposed extinction-causing environmental changes resulting from extraterretrial impact. In light of these published works, we attempt to explicate the patterns and causes of planktonic foraminiferal mass extinction at the K/Pg boundary of the successions located in Northern and west Central Sinai, with the aid of two multivariate data analysis techniques (hierarchical cluster analysis and neighbor joining clustering). © 2008 Springer-Verlag Berlin Heidelberg.