Characterizing Coastal Subenvironments with Modern Foraminiferal Assemblages: Bear Island and Bogue Banks, North Carolina

• Main Author: Shmorhun, Nina Maria-Elena
• Other Authors: Culver, Stephen J., Mallinson, David J., Geological Sciences
• Format: Master Thesis
• Language: English
• Published: East Carolina University 2019
• Subjects: Stratigraphy; Onslow Bay; Bear Island; Geophysics; Foraminifera > North Carolina > Hammocks Beach State Park; Foraminifera > North Carolina > Bogue Banks; Sedimentology > North Carolina > Bogue Banks; Sedimentology > North Carolina > Hammocks Beach State Park; Micropaleontology > North Carolina > Hammocks Beach State Park; Micropaleontology > North Carolina > Bogue Banks; Barrier Island
• Online Access: http://hdl.handle.net/10342/7018

North Carolina's coastline consists of an extensive barrier island system, with inlets acting as pathways for the exchange of sediment and water from estuarine and open ocean environments. Reconstructing past coastal changes in active systems, like those seen in North Carolina, is commonly achieved through the use of a variety of techniques including seismic surveys, sedimentological characterization (e.g., grain-size, lithology, sedimentary structures), and micropaleontological analyses. Foraminifera are common and useful biostratigraphic markers and paleoenvironmental indicators. However, the documentation and utility of foraminifera in coastal systems, can be further developed in nearshore and barrier island related environments (e.g., shoreface, inlet, beach, foreshore). This study aimed to characterize modern foraminiferal assemblages for barrier island-related subenvironments defined a priori, in order to enhance their use as paleoenvironmental indicators in these active coastal environments. Foraminiferal assemblages in Holocene sediments from vibracores were compared with the established modern dataset to test their ability to differentiate subenvironments in the stratigraphic record. Bear Island (Hammocks Beach State Park) was chosen for its lack of human interference and its proximity of previously collected core material from Bogue Inlet and offshore of Bogue Banks, North Carolina. Twenty-six subenvironments from shoreface, inlet, and beach environments were identified and observed on Bear Island and in Bear Inlet. Three replicate surface samples (0-1 cm) were taken via ponar or hand grab sample from each subenvironment, for a total of 78 samples. Sediments were predominantly fine- to medium-grained quartzose and carbonate-rich (e.g., mollusk fragments, echinoid spines) sands. Eighty foraminiferal taxa were identified dominated by Elphidium excavatum, Quinqueloculina lamarckiana, Ammonia parkinsoniana, Eponides repandus, Quinqueloculina seminula, and Ammonia tepida. Discriminant analysis was used to ...