Causes of mass extinction at the K/Pg boundary: A case study from the North African Plate

Abstract

"Humans are responsible for the worst spate of extinctions since the dinosaurs and must make unprecedented extra efforts to reach a goal of slowing losses by 2010" This sentence was mentioned in the UN report dated 3/21/2006. However, are the causes same as those resulted in the five major mass extinctions of the fossil record? The answer is, of course, no. Then, what are the causes led to mass extinctions in the fossil record? We herein try to answer this question through the study of the K/Pg boundary of the North African Plate. Twitchett (2006) stated that in the past 25 years the study of the five major mass extinctions of the fossil record (Late Ordovician event, Late Devonian event, Late Permian event, Late Triassic event and the Cretaceous/Paleogene event or K/Pg event) has increased dramatically, with most focus being on the K/Pg event. He added that many aspects of these five events are still debated and there is no common cause or single set of climatic or environmental changes common to these events, although all are associated with evidence for climatic change. Although the causes of mass extinction at the K/Pg boundary seem to be, somewhat, different from those resulted in the other four extinctions, but still there are similar causes like global climate change related to volcanic activities, sea level changes, and fluctuation of environmental factors (e.g. productivity, oxygenation and temperature). There are two major hypotheses for the K/Pg mass extinction event. The first one suggests that the event is a more progressive and multi-causal series of events resulting from a combination of environmental and climatic factors during the latest Maastrichtian including rapid warming followed by abrupt cooling during the last 400 kyr of the Maastrichtian (e.g. Kauffman 1984; Li and Keller 1998a, b; Keller 2002). The second one points to an extremely brief worldwide catastrophe (e.g. Alvarez et al. 1980; Thierstein 1982; Smit et al. 1992; Liu and Olsson 1992; Molina et al. 1998). Unfortunately, most studies on mass extinction at the K/Pg boundary in Egypt stress on lithostratigraphical and biostratigraphical characteristics and neglect the geochemical analyses of carbon and oxygen isotopes. This could be due to the lack of labs prepared for these techniques in most universities and research institutes in Egypt. However, collaborations with foreign institutes in Europe and USA, and elsewhere could facilitate these procedures in the last decade. Hence, the collaboration between the Geology Department at Minia University of Egypt with the Institute and Museum of Paleontology at Tuebingen University of Germany resulted in the fruitful researches in the subject through the Ph. D. of Dr. Dakrory (second author of the present paper) as well as this present study. © 2008 Springer-Verlag Berlin Heidelberg.