CRC - Cretaceous Research Centre
Oceanography and Climate in an extreme Greenhouse World: the Late Cretaceous - Danian of the Northwest Europe

SNF-financed project. An integrated work between Geological Institute, Copenhagen University and GEUS.

During the last 500 million years the Earth has experienced several periods characterised by alternating greenhouse and icehouse conditions. The Late Cretaceous/Danian is a remarkable time interval, governed by global environmental conditions not met before in Earth history -  extreme greenhouse conditions associated with the highest known sea-level stand. A unique depostional environment, the chalk sea, covered large parts of the present continents, and the stability of the macro-environment formed the basis for the evolution of an extremely diverse and highly specialised fauna. The environmental stability is best illustrated by the Cretaceous-Tertiary mass extinction (Alvarez et al. 1980, 1984; Surlyk 1990), where the complex benthic community structure was rapidly re-establised in a few hundred thousand years, much in contrast to the very slow recovery (tens of millions of years) following the Permian-Triassic extinctin. The stable, long-living marine macro-environment of NW Europe provides an unusual possibily to both study long-term (myr) evolution and specialisation of the bethic fauna, and short-term (kyr) effects of external, orbitally-forced climate changes of ecological and depostional conditions in the Milankovitch frequency band (20, 40, 100 and 400 kyr). The traditional paradigm of chalk sedimentation as a passive response to surface production of calcerous microplankton needs to be challaged and new dynamic models have to be developed to better understand the unique ecological and environmental conditions of this extensive epeiric sea.

Project leaders:
Professor Finn Surlyk and Research Professor Lars Stemmerik

Contact:
Susanne Lil Rasmussen slr@geus.dk