Geomorphic Study Links Baffin Bay Ice Shelf to Glacial Stabilization

A basin-spanning ice shelf covering about 150,000 square kilometres of Baffin Bay appears to have stabilized three adjacent ice sheets during the last glacial period, according to a geomorphic study that combined bathymetric data, seismic reflection images and sediment-core evidence.

The Laurentide, Innuitian and Greenland ice sheets coalesced in the semi-enclosed basin between Greenland and Canada when global ice volume peaked between approximately 26,500 and 19,000 years ago. Although the marine-terminating margins of these ice sheets help determine the boundary conditions and sensitivity of their retreat, their configuration during that interval had remained unclear.

To reconstruct those margins, the researchers compiled bathymetric data and examined the morphology of the Baffin Bay continental slope. They traced the maximum-depth imprint of ice-contact features around most of the basin and found evidence for slope-grounded ice during the last glacial interval. The team interpreted these features as the record of a large, basin-spanning ice shelf supported in part by the geometry of the basin.

After correcting the reconstruction for relative sea level, the researchers estimated that the Baffin Bay Ice Shelf was approximately 1,400–2,100 metres thick. Its inferred area of 150,000 square kilometres made it an extensive feature spanning much of the basin. The observations concern an ancient ice configuration rather than the present-day extent of Baffin Bay ice.

The authors infer that the shelf buttressed, mechanically coupled and promoted thickening of the Laurentide, Innuitian and Greenland ice sheets. In their reconstruction, one large floating structure therefore helped support the stability of three neighboring ice-sheet margins. The inference is based on the relationship between the reconstructed shelf and the geomorphic evidence, rather than a direct observation of the three ice sheets interacting with the shelf.

Sediment cores supplied additional evidence for what happened later. From the sediment record, the team inferred that ice-shelf collapse triggered rapid ice-sheet retreat. This interpretation links the abrupt retreat of Northern Hemisphere ice sheets to embayment-scale ice-shelf dynamics: the disappearance of the extensive shelf was followed by rapid reorganization of the surrounding ice.

The evidence comes from a combination of geomorphic observations, bathymetry, seismic reflection images and sediment cores. It therefore supports a reconstruction of an extensive grounded and floating ice system, but the collapse-triggered sequence is an inference from those records rather than a directly observed event. The study also does not establish that the same configuration or response applies to present-day ice sheets.

The authors present the Baffin Bay Ice Shelf as an analogue for understanding how weakening buttresses may affect the retreat of Antarctic ice streams. The comparison highlights the potential importance of ice shelves in organizing the stability of extensive marine ice-sheet margins, but the Baffin Bay reconstruction itself is a study of the last glacial period and does not constitute a forecast of Antarctic ice-stream change.

Subject of Research: Reconstruction of Baffin Bay ice-shelf geometry and its inferred influence on three glacial ice sheets

Article Title: The Baffin Bay Ice Shelf stabilized three adjacent ice sheets during the last glacial period

Article References: Klotsko, S. A., Hatfield, R. G., Reilly, B. T., Jennings, A. E., Newton, A. M. W., Gregory, E. E., Mix, A. C., Stoner, J. S., Walczak, M. H., Austermann, J., & Lewright, L. (2026). The Baffin Bay Ice Shelf stabilized three adjacent ice sheets during the last glacial period. Nature Geoscience. https://doi.org/10.1038/s41561-026-02126-7

Image Credits: AI Generated

DOI: 10.1038/s41561-026-02126-7

Keywords: Baffin Bay, ice shelf, ice sheets, last glacial period, geomorphology, bathymetry, seismic reflection, sediment cores, glacial retreat, Laurentide Ice Sheet, Innuitian Ice Sheet, Greenland Ice Sheet