Laurentide-Cordilleran Ice Sheet saddle collapse as a contribution to meltwater pulse 1A

Abstract

The source or sources of meltwater pulse 1A (MWP-1A) at similar to 14.5ka, recorded at widely distributed sites as a sea level rise of similar to 10-20m in less than 500years, is uncertain. A recent ice modeling study of North America and Greenland has suggested that the collapse of an ice saddle between the Laurentide and Cordilleran ice sheets, with a eustatic sea level equivalent (ESLE) of similar to 10m, may have been the dominant contributor to MWP-1A. To test this suggestion, we predict gravitationally self-consistent sea level changes from the Last Glacial Maximum to the present day associated with the ice model. We find that a combination of the saddle collapse scenario and melting outside North America and Greenland with an ESLE of similar to 3m yields sea level changes across MWP-1A that are consistent with far-field sea level records at Barbados, Tahiti, and Sunda Shelf.