This project focuses on two Palaeozoic mass extinction events: the Frasnian-Famennian crisis of the Late Devonian and the end-Guadalupian event of the Permian for which similar extinction mechanisms have been proposed. These have been evaluated by examining the nature of the Sr and S isotopic systems during these intervals. Proposed extinction mechanisms for the Late Devonian event include extraterrestrial impacts, rapid sea-level fluctuations, climate change eutrophication and the spread of anoxia in bottom waters. Many models invoke changes in nutrient fluxes related to proposed increases in continental weathering or hydrothermal/volcanic fluxes but these theories have not been tested on a global scale. This study attempted to address this by compiling high resolution 87Sr/86Sr ratio curves for an interval spanning the FrasnianFamennian boundary based on measurements in well-preserved conodont apatite from sections in Poland and Iowa.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:493302 |
| Date | January 2008 |
| Creators | John, Eleanor Heulwen |
| Publisher | University of Leeds |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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