Maximum sea levels for the last glacial period from U-series ages of submerged speleothems

Pleistocene sea levels reflect changes in the surface distribution of land, sea and ice, which in turn significantly influence the Earth's climate ¹. The most complete record of sea levels for the last glacial cycle has come from raised coral reef terraces of the Huon Peninsula, Papua New Guinea^2-4, but interpretation of this record is hampered by relatively large age uncertainties and the possibility of variation in the rate of tectonic uplift. Subaerial speleothems (stalagmites, stalactites and flowstones) from submerged caves in tetonically stable areas provide an alternative source of data^5-8, as their growth stops when rising sea levels flood the caves. Previous studies of speleothems have been limited by dating precision^5,6 and sample availability^5-7. Here we present high-precision thermal- ionization mass-spectrometric ²³⁰Th ages^9-11 for a comprehensive suite of speleothem samples from the Bahamas. Our results provide a record of maximum elevation of sea levels for the period from 80 to 10 kyr before the present, for much of which sea levels are poorly known. We also find that regional palaeoclimatic change can be an important factor in the termination of speleothem growth.