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 (Gregoire et al., 2012) 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 Gregoire et al. (2012) 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.