Extended late Holocene relative sea-level histories for North Carolina, USA
Authors: Kemp, Andrew; Kegel, Jessica; Culver, Stephen; Barber, Don; Mallinson, David; Leorri, Eduardo; Bernhardt, Christopher; Cahill, Niamh; Riggs, Stanley; Woodson, Anna; Mulligan, Ryan; Horton, Benjamin
QUATERNARY SCIENCE REVIEWS, 13-30, V. 160; Elsevier, 2017.
HIGHLIGHTS:
• We extended the late Holocene sea-level record for North Carolina to cover the past 3000 years.
• Extended sea-level records were generated at two separate locations along the North Carolina coast.
• At both locations, the modern rate of sea-level rise is fastest for at least 3000 years.
• Ocean/atmosphere dynamics likely caused regional-scale sea-level variations at ∼1000CE.
ABSTRACT: We produced ~3000-year long relative sea-level (RSL) histories for two sites in North Carolina (USA) using foraminifera preserved in new and existing cores of dated salt-marsh sediment. At Cedar Island, RSL rose by ~2.4 m during the past ~3000 years compared to ~3.3 m at Roanoke Island. This spatial difference arises primarily from differential GIA that caused late Holocene RSL rise to be 0.1 to 0.2 mm/yr faster at Roanoke Island than at Cedar Island. However, a non-linear difference in RSL between the two study regions (particularly from ~0 CE to ~1250 CE) indicates that additional local- to regional-scale processes drove centennial-scale RSL change in North Carolina. Therefore, the Cedar Island and Roanoke Island records should be considered as independent of one another. Between-site differences on sub-millennial timescales cannot be adequately explained by non-stationary tides, sediment compaction, or local sediment dynamics. We propose that a period of accelerating RS L rise from ~600 CE to 1100 CE that is present at Roanoke Island (and other sites north of Cape Hatteras at least as far as Connecticut), but absent at Cedar Island (and other sites south of Cape Hatteras at least as far as northeastern Florida) is a local-to regional-scale effect of dynamic ocean and/or atmospheric circulation.