17 Nearshore and Estuarine Research: Dynamics and Future Resiliency in the Coastal Zone

This session focuses on drivers of change in coastal environments as well as planning for future resiliency in tidal marshes, mudflats, estuaries, and barrier systems, including human activity impacts, sea level rise, & changing sediment supply.

Monday, 23 March 2026
8:00 AM - 12:00 PM
CCC, Room 22/23

Paleoenvironmental Reconstruction of Holocene Relative Sea-Level Change Adjacent to the Adam’s Point and Burnham Archaeological Sites, Great Bay, New Hampshire

Paper number: 17-7
Program: Technical Sessions
Time: 10:00 AM – 10:20 AM

Authors

Abstract

Within New Hampshire’s ‘hidden coast’ lies the Great Bay, a recessed estuarine system that formed following late Pleistocene deglaciation and records complex relative sea-level change throughout the Holocene. Dynamic interactions between isostatic rebound and eustatic sea-level rise produced a sequence of marine transgressive and regressive events that are seen through diverse stratigraphic sequences of marine clays, rhythmic varves, and estuarine accumulation. The Great Bay Estuary also possesses a rich indigenous history, with at least a dozen documented archaeology sites around the bay’s perimeter that indicate occupation and utilization of local marine resources throughout the Woodland Period and into the Contact Era. To better understand the paleoenvironmental framework for Indigenous occupation within the Great Bay Estuary, terrestrial vibracores were strategically extracted from Adam’s Point near Crommet Creek, and from the Burnham Site, near Horsehide Brook. These cores were designed to capture stratigraphic sequences that reflect sediment deposition histories, changes in RSL throughout the Pleistocene and Holocene, and broader site formation processes. Seven vibracores were taken in total that range between 1-3 meters in depth, and followed a lab sequence of z-stacking panoramic photography, loss-on-ignition (LOI), portable X-ray fluorescence (pXRF), and grain-size analysis. Radiocarbon dating of estuarine cores at each site was also done to produce calibrated age-depth accumulation models. By integrating sedimentological data with archaeological context, this project aims to develop a hyper-localized RSL curve adjacent to vulnerable archaeological sites threatened by sea level rise.

Geological Society of America Abstracts with Programs. Vol. 58, No. 2

doi: 10.1130/abs/2026NE-411494

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