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Unmasking a mid-Campanian marine extinction event - evidence from fossil vertebrates and stable isotopes

During the last few decades worldwide mass extinctions in the geological record have attracted considerable attention, being some of the most conspicuous events in the history of life.

Whilst the bulk of the collected data has been assembled in order to detect the five major extinction events, numerous smaller-scaled, but still worldwide, exterminations and their important similarities with the major events have been poorly explored and mainly overlooked by the scientific community.

The aim of this research project is to emphasize the extent and mechanisms behind an intercontinental faunal turnover that caused extinction among marine reptiles (primarily mosasaurs) and selachians during the mid-Campanian, i.e. about 80 million years ago in the Upper Cretaceous period. Falling sea levels accompanied by a declining global surface temperature caused a transition from a typical Mesozoic to a 'modern' oceanic circulation that could be one of the causes to the faunal turnover.

 

Collection of Upper Cretaceous marine fossils during the excavation at Åsen, Kristianstad Basin, Sweden.
Collection of Upper Cretaceous marine fossils during the excavation at Åsen, Kristianstad Basin, Sweden.

 

The research project focuses on the Upper Cretaceous of Scandinavia (Kristianstad Basin, southern Sweden) and Lägerdorf in Germany. At the end of the Cretaceous, some 80 million years ago, much of what is now southern Sweden formed part of a vast epicontinental sea bordered to the northeast by an extensive archipelago. The shallow waterway supported a variety of life forms, ranging from belemnites to giant marine reptiles. To investigate the faunal turnover with focus on the selachians collected fossils from Kristianstad Basin are used in statistical analysis.

The stable carbon isotopes have also been measured from sediment samples from Lägerdorf in Germany to examine the connection between the faunal turnover and the delta-13C excursion in northern Europe. Contemporaneous sediments in North America (Texas and Alabama) will be investigated as well compared with northern Europe to analyze the global effects of the faunal turnover. In order to facilitate correlations across the North Atlantic Ocean, high resolution stratigraphy based on belemnites, ammonites and stable carbon isotopes is performed.

 

 

Researchers

Elisabeth Einarsson

Johan Lindgren

Birger Schmitz

 

Contact point: Elisabeth Einarsson

elisabeth.einarsson [at] geol.lu.se

 

LUCCI - Lund University Centre for studies of Carbon Cycle and Climate Interactions

Department of Physical Geography and Ecosystem Science

Lund University

Sölvegatan 12

S-223 62 Lund, Sweden