Paper No. 4
Presentation Time: 8:00 AM-12:00 PM
DEVELOPING HIGH-RESOLUTION RELATIVE SEA-LEVEL RECORDS AND VALIDATING SEA LEVEL INDEX POINTS IN SOUTHERN NORTH CAROLINA
Long-term relative sea-level (RSL) records are a necessary benchmark by which to gauge present accelerated rates of sea-level rise, future sea-level predictions, and their implications to the coastal zone. The east coast of the United States functions as a significant region of latitudinal RSL variability due to the continuous recovery of land from the deglaciation of the Laurentide Ice Sheet since the Last Glacial Maximum (since ~18ka). Differential glacial isostatic adjustment (GIA) along the coastline has caused higher rates of subsidence in areas around the former forbulge maxima near New Jersey and Delaware and lower rates to the north and south of this maxima. However, the coast between southern North Carolina and northern South Carolina is experiencing a slower RSL change then is seen in reconstructed GIA latitudinal trends along the U.S. east coast. It was thought that this could have been attributed to non-isostatic, long-term tectonic processes causing less GIA subsidence of the lithosphere within the region impacted by uplift from the Cape Fear Arch (CFA), an underlying crystalline basement high. A recent study suggests that RSL rise is slower around the CFA than areas to the north and south due to suggested CFA uplift rates of 0.24+0.15mm a-1. On the contrary, older data along the Cape Fear River (CFR) suggests inconsistently high rates of RSL than those observed to the north and south. However, these discrepancies may be due to the possible use of invalid proxies and/or outdated dating techniques from the time these studies were conducted. The purpose of this project is to develop a high-resolution RSL record along the CFR in order to resolve any inconsistencies from past RSL reconstruction techniques and compare this to an open-ocean site along the IntraCoastal Waterway to test for site-specific (local) influences and the influence of the CFR itself. This will be achieved by using agglutinated foraminifera and their relationship to tidal inundation to construct a RSL indicative meaning that is then used along with chronological control to establish sea level index points, which will be assembled into a local sea-level record.