Paper No. 41-20
Presentation Time: 9:00 AM-5:30 PM
RECONSTRUCTING PAST RELATIVE SEA-LEVEL AND ENVIRONMENTAL CHANGE DURING MIS 5A: MICROPALEONTOLOGICAL ANALYSIS OF GOMEZ PIT, VA (~70-80 KA)
We reconstruct changes in relative sea-level and environmental conditions during late interglacial Marine Isotope Stage 5 recorded in marine sediments in a section from the Gomez Pit, southeastern Virginia. Published Uranium-Thorium analyses on fossil corals from this site constrain the age to (~70-80 ka), representing Marine Isotope Stage 5a (MIS 5a). Benthic foraminiferal and ostracode assemblages (environment indicators), in conjunction with pollen/dinoflagellate ratios (distance-from-shoreline proxy), indicate changes in depositional environment and climate during the sea-level high stand. The major species making up the foraminiferal assemblages are Elphidium excavatum clavata, E. exc. seleyensis, E. exc. excavata, Ammonia parkinsoniana, A. tepida, and Bucella frigida. Changes in warm- vs. cool- dominated foraminiferal assemblages correspond with changes in warm vs. cold pollen taxa (e.g., Oak, Hickory, and herbs vs. Fir, Hemlock, and White Spruce). These data indicate that several short-term climatic and relative sea-level fluctuations occurred through the interglacial section studied. Comparing Gomez pit records with those from a core recovered in Eyreville, Virginia on the Delmarva Peninsula shows good agreement in patterns of environmental change during MIS 5a. Our data suggest relative sea-level and climate fluctuations have co-varied during warm periods of the geologic past, potentially providing context for understanding contemporary climate variability along the Eastern Seaboard.