SEDIMENTOLOGIC AND FORAMINIFERAL EVIDENCE OF STORM-DRIVEN SEDIMENT TRANSPORT ON BEAR ISLAND, NORTH CAROLINA

This research is a continuation of a multiyear investigation (2016, 2018, 2019, 2023, and 2024) which aims to trace storm-related sediment transport on Bear Island, North Carolina using foraminiferal and sedimentological data. Samples from 2016, 2023, and 2024 were collected after several years of no hurricane activity and samples from 2018 and 2019 were collected immediately following a hurricane event.

Sedimentologic and foraminiferal samples were collected both offshore and onshore from the top 1 cm of sediment. Sedimentologic samples were evaluated for their mean phi size, sorting, and skewness. In 2024, samples had a sorting of 0.35 to 0.67 phi, a skewness -0.29 to 0.10 phi and a mean phi size range of 1.98 to 2.75 phi. The finest sediment occurred in the dune and tidal channel with the coarsest sediment in the proximal ebb tidal delta.

In the 2024 data, abundant modern foraminiferal taxa include Elphidium excavatum, Ammonia parkinsoniana, Quinqueloculina lamarckiana, Quinqueloculina seminula, Cibicides lobatulus, and Hanzawaia strattoni. More fossil than modern foraminifera characterize dune and proximal overwash subenvironments. Sugary fossil foraminifera are generally more abundant than phosphatic foraminifera. The latter are more abundant in post-hurricane samples of 2018 and 2019. The 2024 sedimentologic and foraminiferal data are similar to data from non-hurricane samples of 2016 and 2023. However, the 2024 sediments have a smaller range of phi size, sorting, and skewness indicating equilibrium conditions of sediment transport during prolonged low energy conditions.