Wellington (AFP) - Scientists say they have drilled deeper than ever beneath the West Antarctic ice sheet, reaching back millions of years to reveal clues that it was once, at least in part, an ocean.
Published on: 02/17/2026 - 1:19 p.m.
According to an international team of 29 researchers from different universities around the world, this vast area contains enough ice to raise global sea levels by four to five meters.
The report from the team called SWAIS2C, published online Wednesday in New Zealand (Tuesday in France), covers their first observations.
They drilled through 523 meters of ice and 228 meters of ancient rock and sediment at Crary Ice Rise, a point on the Ross Reef - an Antarctic ice plain close to New Zealand, said the team led by research organization Earth Sciences New Zealand, Victoria University of Wellington and government agency Antarctica New Zealand.
By drilling through the ice and rock beneath, they recovered samples that reveal what the places looked like, up to 23 million years ago.
Scientists hope that by studying how the ice melted in the past, they will be able to determine the factors that led to its retreat, including the temperature of the ocean at the time.
“Satellite observations over the past decades show that the ice sheet is losing mass at an accelerating rate, but there is uncertainty over whether temperature increases could trigger rapid ice loss,” the report points out.
"Marine organisms"
“Some of the sediments were characteristic of deposits that form under an ice sheet,” underlines Molly Patterson, co-scientific director at Binghamton University in the United States.
But the team also found shell fragments and remains of marine organisms that need light - instead indicating an ocean, an ice shelf floating on the ocean or an ice shelf margin from which icebergs protrude, Patterson said.
Scientists already believed the region had once been an ocean, which would mean a retreat of the Ross Barrier and a potential collapse of the West Antarctic ice sheet.
But when did this happen? This is what remains uncertain.
These new samples provide sequences of environmental conditions over time, as well as direct evidence of the presence of an ocean in this region, assures Ms. Patterson.
According to Huw Horgan of Victoria University of Wellington, another co-leader of the project, initial evidence shows that the samples span the last 23 million years.
This includes periods when Earth's global average temperatures were significantly higher than today, Horgan said.
Drilling was completed in January and samples were transported from Crary Ice Rise more than 1,100 kilometers across the Ross Reef to the Scott Antarctic Base, where they will be sent to New Zealand for further analysis.
© 2026 AFP
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