Southeastern Section - 57th Annual Meeting (10–11 April 2008)

Paper No. 16
Presentation Time: 8:00 AM-12:00 PM


MCMULLEN, Melissa1, HARRIES, Peter J.2, OCHES, Eric A.2, HERBERT, Gregory S.2 and PORTELL, Roger W.3, (1)Department of Geology, University of Cincinnati, P.O. Box 0013, Cincinnati, OH 45221-0013, (2)Department of Geology, University of South Florida, 4202 E. Fowler Ave., SCA 528, Tampa, FL 33620, (3)Florida Museum of Natural History, P.O. Box 117800, University of Florida, Gainesville, FL 32611-7800,

Florida's Late Cenozoic stratigraphy is notoriously variable and known to hinder the correlation of units over broad spatial areas. This study aims to investigate the extent to which Neo-Ulrichian ‘layer-cake' stratigraphy (Brett et al., 2007) can be applied across nine counties in the central portion of Florida's Panhandle. For the concepts of layer cake to be applied ‘frosting layers' – in this study focused on regional disconformities – that form boundaries between ‘cake layers' were identified and correlated using the wealth of information in well cores. Lithology, fossil occurrences, and mineral content were used to correlate cores and to interpret depositional environments, identify unit boundaries and possible event beds. The interval ranging from the Oligocene Suwannee Limestone through Pleistocene sands comprised the studied stratigraphy. This interval comprises a number of units including: the Hawthorn and Alum Bluff groups as well as the Jackson Bluff and Citronelle formations in addition to various undifferentiated sands and clays. Initial descriptions were obtained from the SOFIA database and augmented through examination of preserved cores within the facility maintained by the Florida Geological Survey as well as by fieldwork at selected localities. The data gathered from SOFIA was imported into RockWorks® to compare individual cores and to produce 3D models of stratigraphic units. Broadly representative fossil occurrence data was analyzed for individual cores and total percentages for each unit containing a fossil were calculated to help characterize specific stratigraphic units. By correlating 300 cores across the area and tracing out the lateral extent and variability of each stratigraphic unit, a regional map displaying depositional environments and how they shifted with time was constructed. This is especially critical in a passive-margin, coastal settings where a single stratigraphic unit may encompass several different, but coextensive depositional environments and the potential for sea-level-induced reworking and erosion is high. It was also evident that concepts of Neo-Ulrichian layer-cake stratigraphy could be applied even in such a dynamic setting as the Florida Panhandle and that despite the lithostratigraphic complexity units could be traced across the study area.