DEFINING THE STRATIGRAPHIC AND PALEOENVIRONMENTAL RECORD OF RAPID SEA-LEVEL RISE DURING THE LATE PLEISTOCENE TO HOLOCENE IN THE ALBEMARLE SOUND REGION OF NORTH CAROLINA

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Erik Kenneth Gudmunson (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: Sea-level fluctuations throughout the late Quaternary Period are recorded in the shallow stratigraphy and modern geomorphology of coastal North Carolina. In the Albemarle Sound region, four distinct Pleistocene sea-level highstand units occur between the late Pleistocene shoreline, marked by the Suffolk Scarp, and the modern ocean shoreline (a distance up to 120 km). Lithofacies and geophysical (ground penetrating radar and CHIRP seismic) data reveal the presence of multiple paleoenvironments during these highstand periods. These deposits are chronostratigraphically and lithostratigraphically categorized into depositional sequences (DS1-4), each separated by a subaerial unconformity or transgressive ravinement surface. DS1 and DS2 contain marine facies (shoreline, shallow shelf, and shoal) with DS1 representing marine deposition during either MIS5e or MIS5c and DS2 representing MIS5a transgressive deposits based on OSL age estimates (91.8 ? 6.3 ka and 93.4 ? 6.3). Overlying DS2, DS3 is dominated by marginal marine and fluvial facies interpreted to include estuarine, tidal flat, and braidplain paleoenvironments. Radiocarbon and OSL age data from this sequence suggest deposition occurred during MIS3. The uppermost sequence DS4, consists of Holocene valley-fill primarily within the Albemarle Sound, and marsh and swamp forest peat. \nCorrelations of facies throughout the Albemarle Sound, paired with those interpreted in comparable studies in the region reveal how coastal North Carolina’s geomorphology responded to relative sea-level changes during the late Pleistocene. The geologic characteristics of these depositional sequences and their corresponding depositional environments provide an analog for future conditions. The results of this study indicate that with current rates of regional sea-level rise (3.4 mm/yr) the wave dominated estuarine system of the present Albemarle Sound region will likely transition to an extensive tidal flat system comparable to the interpreted MIS3 paleoenvironment.

Additional Information

Publication

Thesis

Language: English

Date: 2023

Subjects

Stratigraphy

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