How deep did Antarctic drilling go?
A record-breaking core under the West Antarctic Ice Sheet
An international drilling expedition has retrieved sediment and rock from deeper below the West Antarctic Ice Sheet than ever before, pulling up a stratigraphic record that stretches back millions of years. The material contains geologic and chemical indicators that at times the site was open ocean or connected to marine conditions, providing direct evidence about past configurations of ice and sea.
Those findings change how scientists reconstruct Antarctica’s behavior during warmer climates. Where cores previously came from exposed continental shelves or coastal margins, these under-ice sediments can preserve uninterrupted records of ice-sheet presence, retreat, and regrowth. The discovery of marine signatures deep beneath the ice demonstrates that the ice sheet once retreated far enough to let seawater or marine deposition into that location.
What this lets researchers do:
- Pinpoint episodes when the ice sheet thinned or retreated, and the environmental conditions that accompanied those changes.
- Compare past sea-level responses to known climate forcings to test models of ice-sheet sensitivity.
- Improve projections of future sea-level rise by constraining thresholds and rates of ice loss.
The core also offers material for multiple laboratory techniques — sedimentology, isotope geochemistry, microfossil analysis — that together build a timeline of environmental change. While the record shows that marine conditions existed beneath modern ice at some point, it does not by itself specify how rapid those transitions were or the exact global sea-level consequences. Those details will emerge as teams analyze the core, date its layers, and integrate the results with ice-sheet and climate models. For coastal communities and policymakers, the work sharpens the empirical basis for anticipating how Antarctic ice might behave under continued warming.