A LATE QUATERNARY SEA-LEVEL CURVE FROM DELAWARE: IMPLICATIONS FOR GEOPHYSICAL MODELLING

High quality relative sea-level (RSL) data reveal spatial and temporal variations in crustal movements since the Last Glacial Maximum (LGM). Current concerns regarding the potential eustatic sea-level rise associated with anthropogenic warming of the atmosphere and oceans and its impacts on coastal resources have resulted in increased interest in former RSL fluctuations. Rates of sea-level rise obtained since the LGM represent the fundamental basis for comparison with the historical and present day changes. Reconstructions through the Holocene allow modellers to quantify lithospheric thickness and mantle viscosity and establish lateral variations in mantle structure across the continental/oceanic margin.

There is an urgent need to re-evaluate the quality of the United States Atlantic coast RSL record, because of the apparent inability of the best currently available Glacial Isostatic Adjustment models to fit the earliest portions of the Holocene records at most sites south of Boston. From an initial database of 212 samples spanning a temporal period of 20000 years (145±145 cal yrs BP to 20150±700 cal yrs BP), we have compiled a quality-controlled database of sea-level index points for the state of Delaware following established protocols for judging the reliability of sea-level observations. The index points demonstrate the rise in sea-level from the termination of the LGM through to the present day.