61st Annual Report on Research 2016

Two undergraduates commenced work on this project in September 2015. Eight vibracores (four for each student) were selected from a suite of vibracores collected in Onslow Bay, North Carolina. One student worked on cores from the shoreface and inner shelf off Bogue Banks and the other on cores from the Bogue Inlet complex (inlet channel and ebb tide delta). Cores were logged and Holocene sediment was sampled for grain-size and foraminifera.

The two undergraduate students successfully completed Honors theses in May 2016. One demonstrated that the shoreface and inner shelf subenvironments, although similar in sediment characteristics, could be distinguished based on foraminiferal assemblages (greater proportions of miliolids in shoreface than inner shelf sediments). The other student similarly demonstrated that, despite similar sedimentary characteristics, inlet channel and ebb tide delta subenvironments could be distinguished by foraminiferal assemblages (higher diversity and greater proportions of miliolids in the ebb tide delta). The inlet channel samples also contained ~36% reworked (probably Miocene) foraminifera derived from outcrops on the bed of Onslow Bay. Thus, all four subenvironments studied in Holocene sediments during this first year of the project could be distinguished based on foraminiferal assemblages. The students presented the results of their work in posters at the South East Geological Society of America Conference, Columbia, SC in March/April 2016.

A Master’s student joined the project in January 2016 and successfully defended her research proposal in April 2016. Her task is to characterize modern siliciclastic coastal subenvironments with foraminiferal assemblages of Bear Island, North Carolina (immediately adjacent to Bogue Banks). The goal is to provide a model whereby Holocene samples from cores worked on by undergraduate students can be classified via statistical means (multiple discriminant analysis) into known subenvironments of deposition based on foraminiferal assemblages. Field work was conducted over summer 2016 and samples from the majority of 26 modern subenvironments were collected (the remainder will be collected in October, 2016). Sediment data were collected at each sample site and elevation profiles were surveyed for all sites. A poster presenting the preliminary results of the work was presented at the national Geological Society of America conference in Denver, September 2016.

Two new undergraduate students joined the project in September 2016. They contributed to core selection and are conducting readings before commencing core logging. Their research will be modeled on that of their predecessors. One of the undergraduate students from the first year of this project is now a graduate student in Geological Sciences at East Carolina University.