Sea Level Record: Applications to Global Climate

This award supports offshore coring into the coral reefs of Barbados to retrieve a detailed sea level record for the past 20,000 years. U-series dating of the reef crest coral indicates that sea level was approximately 120 meters below present sea level during the last glacial maximum. Sea level rise was not monotonic; rather, it was marked by a series of jumps with rates of sea level rise exceeding 2cm per year at least three times during the deglaciation. The glacial meltwater associated with this sea level rise is clearly recorded in the oxygen isotopic records of planktonic foraminifera. Immediately preceding this sea level jump was the initiation of North Atlantic Deep Water production and associated meridional heat transport. Measurement of C-14 and U-Series ages on the same coral samples, will also provide a unique opportunity to calibrate the C- 14 time scale beyond the 10,000 year dendrochronology. The radiocarbon calibration beyond 10,000 years is critical for climate research that compares radiocarbon-dated proxies with absolute chronologies based on annual layer counting, such as ice core records or astronomical calculation. These results have immediate implications for climate and geophysical models that incorporate phase lags or rates of climate change based on calibrated radiocarbon records.