Late Ordovician Epeiric Sea Circulation, Environmental Change, and Biotic Turnover: Model and Data Synthesis
One of the most difficult problems facing the earth science community today is identifying the ultimate causes of extinction and migration in the history of life. In the sedimentary record, biotic change such as extinction is often linked to evidence of environmental change, however the processes underlying environmental change are often complex and poorly understood. Numerical models of physical systems that are tested against the sedimentary record provide a means by which the ultimate causes for bioevents can be investigated. We propose to use a numerical model of ocean circulation to determine the ultimate causes for an extinction event in the Late Ordovician of North America.
This study has two main components. In the first component we hypothesize that rapid shifts in environmental conditions linked to extinction during the Late Ordovician of North America were caused by changes in bathymetry, paleogeography, and precipitation associated with mountain building. We will model ocean circulation for two time intervals that span the abrupt shift in environmental conditions and related extinction event. We will test the validity of the model results against the distribution of sedimentary indicators of oceanographic conditions.
In the second component of the study we will investigate the relative importance of single variables like changes in sea level, paleogeography, bathymetry, and precipitation in producing rapid oceanographic shifts in the epeiric seas that may have caused significant extinction of species. In investigating the ultimate causes of extinction, modeling has the advantage that single variables can be isolated and their effects on the system evaluated. We will identify plausible causes of the extinction event by determining how well the model results match the spatial and temporal faunal changes. By gaining insight into the causes of rapid oceanographic changes in these epeiric seas, this study has broad implications for understanding environmental change and extinction during any time in Earth's history when epeiric seas were important components of marine ecosystems.
|Effective start/end date||9/1/01 → 8/31/05|
- National Science Foundation: $179,992.00