Abstract
We have constructed a database of Holocene relative sea level (RSL) observations for the Atlantic coast of the United States. The database contains 492 index points, which locate the position of RSL in time and space, and 344 limiting dates, which constrain the minimum or maximum limit of former sea level. The majority of the index points in the database are from 6 ka BP to present, with only 7% older than 6 ka BP. Spatially, index points are distributed between Maine and South Carolina, but there is an absence of data from Georgia and the Atlantic coast of Florida.
The database is sub-divided into 16 regions based on the distance from the former Laurentide Ice Sheet and are classified depending upon their susceptibility to compaction. The index points and limiting data demonstrate that RSL did not exceed present (0 m) during the Holocene except potentially in regions 1 and 2 (Eastern Maine and Southern Maine). Rates of RSL change were highest during the early Holocene and have decreased over time, due to the diminishing response of the Earth’s mantle to glacial isostatic adjustment and reduction of ice equivalent meltwater input. Along the Atlantic coast of the United States the linear rate of RSL rise prior to 4 ka BP ranged from 0.5 to 4.5 mm a−1, compared to 0.6–1.8 mm a−1 from 4 ka BP to AD 1900. The database suggests minimal (<0.3 mm r)="" changes="" in="" these="" rates="" of="" rsl="" rise="" during="" the="" late="" holocene.="" deglaciation="" of="" the="" laurentide="" ice="" sheet="" caused="" the="" spatial="" variability="" captured="" by="" the="" database.="" the="" maximum="" rate="" of="" late="" holocene="" (and="" ongoing)="" rsl="" rise="" occurred="" in="" mid-atlantic="" regions="" (new="" jersey="" and="" inner="" delaware)="" because="" of="" collapse="" of="" the="" peripheral="">
Keywords
Glacial isostatic adjustment, Holocene, Laurentide Ice Sheet, Relative sea level, Salt marsh, United States Atlantic coast