Group
Members
"The present is the key to the past"
Uniformitarianism; James Hutton
..can the past also be the key to the future?
James Witts (Ph.D. Student)
Marine biodiversity during the latest Cretaceous in Antarctica and the nature of the Cretaceous-Paleogene mass extinction
Ongoing research in Antarctica has identified the excellent exposures on Seymour Island to be the best high-latitude site in the world for studying the Cretaceous-Paleogene (K/Pg or K/T) mass extinction of ~65Ma. Previous studies have hinted at an apparently protracted extinction event (compared to the more abrupt record seen in some low latitude sections) in sediments that show little lithological change, although a small iridium spike has been reported. Detailed palynological studies completed between BAS and the University of Leeds have helped to resolve the position of the boundary and thus allow comparison with events elsewhere.
The aim of my project is to assess how the marine macrofauna responded both to changing climatic conditions in the Maastrichtian, and the K/Pg crisis, by a thorough evaluation of the pre-extinction Maastrichtian communities, the fauna of the boundary interval and the post-extinction, earliest Paleocene fauna. Large fossil collections from Seymour Island held at the University of Leeds and British Antarctic Survey will be examined in detail with the aim of producing range charts of the abundant invertebrate fauna, as well as details of changing palaeoecology of the section through the Maastrichtian and K/Pg interval. It is hoped comparison can be made with available data from contemporaneous lower latitude sections and allow evaluation of latitudinal and taxonomic selectivity of the mass extinction.
The excellent preservation of the Seymour Island fossils, with aragonite and calcite shell material present, together with the presence of abundant fossil wood throughout the sequence, also provides the opportunity for geochemical assessment of the section. This will include generation of carbon isotope curves, as well as a study of the ocean sulphur cycle through an analysis of the carbonate-associated-sulphate (CAS). This data will allow examination of changes in the controls on S cycle fluxes, namely ocean redox, and global weathering rate variations at the time of the K/Pg crisis.
This project is supervised by Professor Paul Wignall, Professor Jane Francis, and Dr. Rob Newton (all University of Leeds), as well as Dr. Alistair Crame (British Antarctic Survey).
email: j.witts@leeds.ac.uk
web: http://www.see.leeds.ac.uk/people/j.witts
