Speleothem constraints on marine isotope stage (MIS) 5 relative sea-levels, Yucatan Peninsula, Mexico

Rates of sea-level fall at the termination of the last interglacial are poorly defined and archives from which sea-level elevations are constrained during marine isotope stage (MIS) 5 in the western North Atlantic–Caribbean region are restricted spatially to a few key sites. Here, growth periods of presently submerged but subaerially deposited speleothems from the Yucatan Peninsula, south-east Mexico, are dated using the 230Th/234U multi-collector inductively coupled plasma mass spectrometric method. The growth periods, used to constrain maximum elevations of relative sea level, are in agreement with glacio-isostatic adjustment models for the near to intermediate region of the former North American ice sheets. Furthermore, our data provide additional constraints on the timing of peak relative sea levels during MIS 5a and 5c, and the timing of the regression following the last interglacial highstand. Combining our data with coral archives of minimum relative sea level from the same region provides a novel approach to calculating the rate of relative sea-level fall, although initial estimates are poorly constrained because of the wide range in ages observed for the most suitable corals.