Type of Document Thesis Author Willett, Michael Alan URN etd-05042006-163100 Title Effect of Dissolution of the Florida Carbonate Platform on Isostatic Uplift and Relative Sea-Level Change Degree Master of Science Department Geological Sciences, Department Advisory Committee
Advisor Name Title Joseph F. Donoghue Committee Chair Jennifer E. Georgen Committee Member Sergio Fagherazzi Committee Member Sherwood W. Wise Committee Member Keywords
Date of Defense 2005-04-25 Availability unrestricted Abstract
Florida is typically considered to be tectonically stable and representative of global eustatic sea level with little evidence for any anomalous local subsidence or uplift during the late Cenozoic. Sea level during most of that time did not significantly rise above the present level. However, paleoshoreline features near the border of northern Florida and southern Georgia have been found to contain marine fossils of Pleistocene age at elevations of between 42 and 49 m above mean sea level, suggesting that some mechanism of epeirogenic uplift has affected the area. A possible cause of uplift during the late Cenozoic is mass removal from the Florida carbonate platform via karst-related groundwater dissolution.
Calculations carried out as a part of this study, using measurements of dissolved carbonate in Florida’s first- and second-magnitude springs, shows that the karst area of central and north Florida is losing a minimum of 4.8 x 105 m3 /yr of limestone. This carbonate mass loss is equivalent to an approximate thickness of 1 meter of limestone every 160,000 years. The impact of long-term carbonate dissolution and mass loss from the Florida platform has led to isostatic uplift of at least 9 m and as much 58 m since the beginning of the Quaternary (~1.6 Ma). These results were obtained using the measured mass loss rate and calculation of the isostatic response to unloading of the Florida platform. Isostatic uplift due to dissolution of the Florida platform would at least in part explain the occurrence of Plio-Pleistocene marine fossils at elevations significantly higher than sea levels are known to have been during that time.
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