MACROFAUNAL DISTRIBUTION AND STRATIGRAPHIC FACIES CHANGE IN THE CLAYTON FORMATION OF OKTIBBEHA COUNTY, MISSISSIPPI

The Clayton Formation is an Early Paleocene marine sedimentary formation of the Midway Group. The Clayton Formation is characterized by several limestone, clay, and sand members of varying grain size and composition. In Oktibbeha County, Mississippi, the Clayton Formation outcrops in several locations on the western side of the county. The Clayton Formation is notable for being the first Paleogene unit in the eastern Gulf Coastal Plain to be deposited after the Cretaceous-Paleogene (K-Pg) extinction event and overlies the Late Cretaceous Prairie Bluff Chalk found in east-central Mississippi and west Alabama. In Oktibbeha County, fossils of various marine taxa, ranging from larger organisms such as Paleogene sharks and bony fishes to smaller invertebrates and microfossils, have been found and recovered from the Clayton. Since this is the first unit to be deposited in this area following the K-Pg extinction event, analysis of these fossils may reveal faunal and thus environmental changes following the event. Faunal changes across this boundary have been documented at other locations, such as the Gulf of Mexico and Alabama, however little information has been produced on this subject in Mississippi. This research is examining a largely undocumented geologic formation that was deposited after the second largest mass extinction in geologic history, and key findings in this study could provide new explanations or confirm previously proposed assumptions about life following the Cretaceous-Paleogene extinction. This research reports on initial macrofossil analyses from three Oktibbeha County outcrop locations.