Barrier island response to late Holocene climate events, North Carolina, USA

Abstract

The Outer Banks barrier islands of North Carolina, USA, contain a geologic record of inlet activity that extends from ca. 2200 cal yr BP to the present, and can be used as a proxy for storm activity. Optically stimulated luminescence (OSL) dating (26 samples) of inlet-fill and flood tide delta deposits, recognized in cores and geophysical data, provides the basis for understanding the chronology of storm impacts and comparison to other paleoclimate proxy data. OSL ages of historical inlet fill compare favorably to historical documentation of inlet activity, providing confidence in the technique. Comparison suggests that the Medieval Warm Period (MWP) and Little Ice Age (LIA) were both characterized by elevated storm conditions as indicated by much greater inlet activity relative to today. Given present understanding of atmospheric circulation patterns and sea-surface temperatures during the MWP and LIA, we suggest that increased inlet activity during the MWP responded to intensified hurricane impacts, while elevated inlet activity during the LIA was in response to increased nor'easter activity. A general decrease in storminess at mid-latitudes in the North Atlantic over the last 300 yr has allowed the system to evolve into a more continuous barrier with few inlets.

Subsurface Evidence of Storm-Driven Breaching along a Transgressing Barrier System, Cape Cod, U.S.A.

“…Between 1846 and 2008, the shoreline retreated landward by 70 m at a long-term rate of 0.43 m/y (Maio et al, 2014). The destabilization of barrier systems in response to accelerated rates of sea level rise coupled with high-energy storm events has been observed along coastal barriers along the U.S. East Coast and the Gulf of Mexico (Ashton, Donnelly, and Evans, 2008;Mallinson et al, 2011;Seminack and Buynevich, 2001). Numerous studies have shown that coastal barriers are rapidly migrating landward and degrading (FitzGerald, Buynevich, and Rosen, 2001;FitzGerald et al, 2007;Khalil, Finkl, and Raynie, 2013;Mallinson et al, 2010;Williams, Penland, and Sallenger, 1992).…”

“…Storm-driven barrier breaching and the formation of new inlets can lead to dramatic perturbations in adjacent coastal landforms and ecosystems (Buynevich and FitzGerald, 2003;Mallinson et al, 2011). These include a potential rapid increase in wave and tidal energy within back-barrier settings, the salinization of freshwater environments, alterations to important marine transportation routes, and the destruction of coastal infrastructure (Buynevich and FitzGerald, 2003;FitzGerald, van Heteren, and Montello, 1994;Maio et al, 2014;Mallinson et al, 2011).…”

“…These include a potential rapid increase in wave and tidal energy within back-barrier settings, the salinization of freshwater environments, alterations to important marine transportation routes, and the destruction of coastal infrastructure (Buynevich and FitzGerald, 2003;FitzGerald, van Heteren, and Montello, 1994;Maio et al, 2014;Mallinson et al, 2011). Because of these factors, developing a long-term understanding of barrier inlet dynamics and susceptibility to breaching events is a critical topic to be addressed and is a major concern for coastal managers and engineers (FitzGerald et al, 2008;Khalil, Finkl, and Raynie, 2013;Seminack and Buynevich, 2013).…”

Late Holocene Evolution of Currituck Sound, North Carolina, USA: Environmental Change Driven by Sea-Level Rise, Storms, and Barrier Island Morphology

“…Two quartz sanddominated samples were sent to Utah State University Luminescence Laboratory for OSL analysis using the single aliquot regenerative (SAR) method. Preparation followed the general procedures outlined in Mallinson et al (2011). OSL ages are converted to cal yr BP by subtracting 62 years (samples were analyzed in 2012).…”

“…This reflects the historically documented closures of many inlets in the Outer Banks (Figure 1). Mallinson et al (2011) suggested that inlet closure could be related to fewer storm impacts during the past 300 years. New Currituck Inlet closed around 200 years ago (Stick, 1958;Fisher, 1962) almost completely closing off Currituck Sound from any marine influence.…”