CALIBRATING A SEDIMENTARY RECORD OF HURRICANE OVERWASH DEPOSITION FROM QUISSETT HARBOR, WOODS HOLE, MA

The climatic variabilities that govern the formation, frequency, and severity of Atlantic hurricanes are poorly understood. The historic record of North Atlantic hurricane landfalls is limited to at best the four centuries since European settlement of the east coast of the United States, severely limiting the capacity to observe and analyze trends in activity and understand their linkages to other climatic cycles. This project attempts to reconstruct a longer record of hurricane landfalls in New England through analysis of sediment cores from Quissett Harbor, Woods Hole, Massachusetts. These cores contain a 3000-year sedimentary record, with variability in grain size consistent with overwash events linked to hurricane landfalls. Modern events can be loosely correlated with the historic record of severe hurricanes. More extensive dating efforts will be necessary to more definitively establish this timeline, including mercury analysis on the upper meter of one core, which will be correlated with established chronologies of atmospheric mercury deposited in the region. Longer-term variations in storm activity are consistent with patterns observed in previous studies, with two active intervals since 1600 years before present, a third approximately 2000-2400 years before present, and a fourth approximately 2700-3000 years before present. This analysis further indicates a potential transition from a coastal pond to a harbor, which suggests an increased sensitivity to overwash events. To assist in evaluating this transition and calibrating the record of storm overwash events, C/N ratios and δ¹³C and δ¹⁵N values will be analyzed to indicate a possible change in the origin of organic matter in core sediments from terrestrial to marine sources.