Elucidating the Holocene Relative Sea-Level History of the US Atlantic Coast
Abstract
There is an urgent need for a re-assessment of the quality of Holocene relative sea-level (RSL) observations from the Atlantic and Gulf coasts of the United States. Holocene RSL data provide an essential benchmark to compare against other records of RSL change in the last 100-150 years. Only high quality sea-level data reveal spatial and temporal variations in crustal movements since the Last Glacial Maximum and provide a vital constraint upon dynamical models of the Glacial Isostatic Adjustment (GIA) process. We require an accurate model of the GIA process to inform the global data set currently being produced on the time dependence of the gravitational field of the planet by the Gravity Recovery and Climate Experiment (GRACE). We have compiled database of 1400 possible sea-level index points for the Atlantic coast of the United States. These unvalidated data contain much scatter due to concepts inherent in their original interpretation. They rarely allow for other factors such as sediment compaction and tidal range variation. Following validation, results from Delaware and North Carolina show a rapid rise in RSL from the early to mid Holocene, with no evidence of sea- level above present. They also differ somewhat from GIA model predictions. Rates of RSL change during the late Holocene divide into three broad zones: (1) Maine to Boston, MA ~ RSL rise of less than 1 mm yr-1; (2) Cape Cod, MA to Maryland ~ RSL rise between 1 and 3 mm yr-1; and (3) North Carolina to South Carolina ~ RSL rise less than 1 mm yr-1. Comparison with tide-gauge records demonstrate an increase of at least 1 mm yr-1 at all sites since AD 1900.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- Bibcode:
- 2007AGUFMPP51B0477E
- Keywords:
-
- 0545 Modeling (4255);
- 1236 Rheology of the lithosphere and mantle (7218;
- 8160);
- 1641 Sea level change (1222;
- 1225;
- 4556);
- 4556 Sea level: variations and mean (1222;
- 1225;
- 1641);
- 4926 Glacial