87 Marine/Coastal Science (Posters)

RECONSTRUCTING RELATIVE SEA-LEVEL ON THE OUTER BANKS, NORTH CAROLINA: A MICROFOSSIL BASED TRANSFER FUNCTION APPROACH

Paper number: 87-3
Program: Technical Sessions
Time: 8:00 AM – 12:00 PM

Authors

Abstract

The need for high resolution sea-level reconstruction has increased drastically with the realization that global warming may accelerate the rate of sea-level rise, resulting in increased coastal flooding. A microfossil based transfer function approach can produce sea-level records of appropriate length and resolution to better understand the relationship between sea-level and climate. Furthermore, these records can address the disconnect between instrumental records and geological reconstructions of relative sea level.

We provide a high resolution relative sea-level history for the Outer Banks, North Carolina. We collected contemporary foraminifera, diatoms and environmental data from three back barrier marshes on the Outer Banks, North Carolina, which have different salinity regimes reflecting distance from a major barrier inlet. Transfer functions were developed to reconstruct former sea-levels using foraminifera, diatoms and a multi-proxy approach combining both groups. These models were based upon the modern, observable relationship between microfossil distributions and elevation (m MSL). Transfer function performance suggests a precision of 0.06m. The degree of precision does not vary significantly with the microfossil employed.

Foraminifera and diatoms were counted from two fossil cores to provide a record of sea-level for the period since ~1850AD. They demonstrate a pattern of rising sea level with an average rate of ~4mm/yr ± 0.3mm. During the interval since 1940AD the average rate is ~6mm/yr ± 0.5mm. Foraminifera, diatoms and multi-proxy models produce sea level histories which are the same within error bounds.