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

The source or sources of meltwater pulse 1A (MWP-1A) at ∼14.5 ka, recorded at widely distributed sites as a sea level rise of ∼10-20 m in less than 500 years, 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 ∼10 m, 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 ∼3 m yields sea level changes across MWP-1A that are consistent with far-field sea level records at Barbados, Tahiti, and Sunda Shelf.