THE STRATIGRAPHIC EXPRESSION OF RAPID PALEOENVIRONMENTAL CHANGE IN AN ESTUARINE SYSTEM: PAMLICO SOUND, NC
The Holocene has been punctuated by rapid climatic changes (RCC) that have impacted coastal North Carolina. Two of these RCC periods, occurring at approximately 4100-3700 cal y BP and 1150-500 cal y BP (during the Medieval Climate Anomaly - MCA), are synchronous with increased marine influence in the Albemarle-Pamlico Estuarine System (APES). Evidence of marine influence is supported by a significant change in the depositional environment as indicated by foraminiferal assemblages. In this project, high resolution seismic data, bulk magnetic susceptibility (BMS) data, sedimentological analyses, and radiocarbon age estimates are being used together to define the chronostratigraphic framework and evolution of the APES. These data have provided evidence that the influence of the MCA event was more spatially widespread within the APES than previously thought. BMS data from multiple cores correlate well to the magnetic stratigraphy found in a core previously studied which contains the best record of increased marine salinity based on foraminiferal assemblages. The MCA event is characterized by a decrease in BMS values within the cores, possibly due to a change in sediment source, likely an increase in marine influence. A semi-continuous seismic reflection in central to western Pamlico Sound correlates with magnetic susceptibility excursions in the cores, and is constrained by radiocarbon age estimates to circa the MCA event. These data suggest significant hydrodynamic changes (increased wave and current energy) occurred within much of the APES in association with regional meteorological and/or sea-level changes during the MCA.