23 Current Research in Coastal and Nearshore Processes (Posters)

Monday, 18 March 2024
9:00 AM - 1:00 PM
Armory Ballroom

INVESTIGATING MID-HOLOCENE TO PRESENT RELATIVE SEA-LEVEL RISE IN SOUTHWESTERN CONNECTICUT

Paper number: 23-3
Program: Theme Sessions
Time: 9:00 AM – 1:00 PM

Authors

Abstract

Reconstructing past sea-level is crucial in understanding coastal dynamics and the evolution of coastal landforms through time. Relative sea-level rise rates provide the basis for assessing projected climate change impacts, informing coastal management practitioners in producing adaptive strategies to sea level rise and aiding ecologists and conservationists in predicting ecosystem responses. In this study, we present a sea-level rise reconstruction, spanning the mid-Holocene to present, for a 203 cm sediment core collected in Smith Cove, Greenwich, CT. From core bottom to top, the major sedimentological units are as follows: glacial till, paleosol, woody peat, and estuarine silt loam. Subdivisions of these units, based on changes in shell content, grain size, organic texture and content, and color, provide further context to the depositional environments with respect to sea level. The woody peat (and encompassing) horizon, preserved below estuarine silt, is indicative of a wetland outpaced and buried by sediment deposited due to rising sea levels, likely beginning in the mid- to late-Holocene. The core was sampled at 2 cm intervals and analyzed for geochemical and sedimentological characteristics. Radiocarbon dates at select intervals provide constraints on the timing of wetland burial and sedimentation throughout the core. Trace metals such as Pb provide information on 20th century sediment ages. Integrating both sets of age data will create a full age-depth model, revealing the complete relative sea level history for this site. This sea level history will be discussed and compared to sites from the literature.

Geological Society of America Abstracts with Programs. Vol. 56, No. 1

doi: 10.1130/abs/2024NE-397782

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