230TH/234U Dating of Barbados Sea Level Record 0-230,000 Years BP

The history of sea level is an important component of paleoclimate research. It defines the history and rate of ice growth and melting, the slowest component of the atmosphere- ocean-cryosphere system. The best record of sea level is produced by using well-dated coral reef material. This proposal requests support to refine the sea level history for the last 125,000 years and to calibrate the 14C time scale for the last 40,000 years. The PIs will use the elevation and morphometry of the coral reef samples from Barbados and their radiometric ages to extend the sea level record to 125,000 years BP. Comparisons between 14C and 230Th ages of coral samples will be used to calibrate the 14C time scale. This research is important because it will: 1) develop the best possible record of sea level and 2) calibrate the 14C time scale back to about 40,000 years BP. Thus it will be possible to compare on the same time scale the records of climate and the astronomical variations which cause climate change.