CARIBBEAN HOLOCENE SEA-LEVEL RISE RECONSTRUCTED FROM COMBINED CORAL AND PEAT DATA

Relative Caribbean sea-level rise over the past 11,000 years has been reconstructed using over 120 coral and peat samples via a two-proxy approach. Non-conventional ¹⁴C dates from the shallow reef crest coral Acropora palmata had previously been used to reconstruct sea level, while bulk, non-conventional ¹⁴C dates from intertidal Rhizopora mangle peat have been routinely used to mark past sea-level positions in microtidal carbonate environments. This reconstruction included more recent high precision TIMS U-Th and ¹⁴C coral data to account for gaps in the coral record. Error corrections to ages and elevations were applied where possible.  All ¹⁴C dates were calibrated using the Calib programs.  Separately, both the peat and coral datasets incorporate sufficient age and elevation uncertainties and error to heavily impact each one's accuracy for sea-level determinations.  However, when combined, data from these paleoenvironmentally-related facies bracket the position of sea level in the form of a smooth curve with two breaks in slope signifying progressive reductions in the rate of sea-level rise during the Holocene.

Currently these datasets lack the time/depth resolution to allow for identifying any sea-level response to rapid climatic events, or for quantifying differential isostatic histories between study sites.  Recent work, however, has allowed testing and validation of the curve's position as well as its utility in interpreting paleo reef and mangrove histories. In addition, the curve provides a reliable reference point for interpreting the record of major storm activity during the Holocene.  Advances in ¹⁴C dating methods since these samples were dated will be assessed using new peat data. Rates of sea-level rise during the Holocene are compared with current Caribbean and Gulf coast rates, as well as with projected rate increases and storm surges under climate warming scenarios.