26 Reconstructing Environmental Change from Marine, Lacustrine, and Terrestrial Sedimentary Records (Posters)

Saturday, 29 March 2025
8:30 AM - 5:30 PM
North Great Hall

ANALYSIS AND COLLECTION OF PALEOSTORM RECORDS FROM BACKBARRIER ENVIRONMENTS IN COASTAL RHODE ISLAND

Paper number: 26-2
Program: Theme Sessions
Time: 8:30 AM – 5:30 PM

Authors

Abstract

The East Coast of the United States is prone to hurricanes and extratropical storms which transport marine sediment into back-barrier environments as they make landfall. Organic-rich sediment accumulates over top of the storm deposits, preserving the layers beneath. Here we present initial sedimentary records of storm-induced overwash from the Napatree Point and Moonstone Barriers, along the Rhode Island south shore. Coring sites were selected to fill the geographic gap in scientific literature away from where other projects had collected sediment cores. The results of this study were correlated to previous work on other sites in Rhode Island. The findings of this study confirm the presence of preserved paleostorm layers at both sites, allowing evidence of overwash to be correlated to past storm events. Carbon-14 and Lead-210 dating, paired with analysis of aerial imagery reveal overwash deposits linked to storm surges from hurricanes hypothesized to include The Great Colonial Hurricane of 1635, Hurricane of 1727, New England’s Snow Hurricane of 1804, Great September Gale of 1815, and the Great September Gale of 1869 at Napatree Point. Storm layers in core samples are influenced by core location and the storm's size, intensity, frequency, and time scale, with bioturbation and surface processes potentially eroding, compressing, or mixing these layers. The westerly position of Napatree relative to previous sites may have captured tropical or extra-tropical storms not previously identified. Future coring will look to corroborate these initial findings. An interesting additional finding is that a prominent sand layer present within the NPCA cores was likely not a paleostorm deposit. This provided further insight into historical land use within the area. The construction and deconstruction of Fort Mansfield (1898-1907) involved land clearing and filling of a wetland, which disturbed the vegetation and facilitated the aggressive spread of Phragmites communis that dominate the area today. The findings within NPCA and Moonstone Beach, combined with the results of previous studies, provide further insight into storm frequency and intensity and offer a better understanding of the impact of coastal storms along the Rhode Island shoreline.

Geological Society of America Abstracts with Programs. Vol. 57, No. 3

doi: 10.1130/abs/2025NE-407732

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