Beyond Epica goes back for a million years, under the ice
Neck and neck with the Australians, Europe’s most ambitious drilling project in Antarctica has reached a depth of 2,000 meters and is well positioned to be the first to reach very old ice.
Crounch, crounch, crounch, from the summit of Antarctica, the ice drills are up and running again, digging vertically into a cap more than two kilometers thick. The Antarctic season could well be the one to break all records, with a very deep drill and ice more than a million years old. Since November 20, the Beyond Epica super-project has been firing up its corer. Last week, this European drill reached a depth of 2,000 meters. “We’re ten days ahead of last year,” enthuses Frédéric Parrenin, paleoclimatologist in charge of coordinating the project on the French side.
Since the opening of the camp on Little Dôme C in 2021, successive missions have taken advantage of the summer months to advance, layer by layer, towards the bedrock. In 2022, drilling reached 110 meters. Although the reopening of the camp the following summer was slowed down, drilling reached 800 metres by the end of the campaign. A wave of Covid and unstable weather had delayed the flights that bring personnel to this site culminating at an altitude of 3,200 meters.
Teams pass through the Italian Mario Zucchelli station on the Ross Sea side, or Dumont d’Urville on Terre Adélie. They then head for Concordia and the camp. The equipment is reconditioned, and this year work resumed at a depth of 1,836 metres. Thanks to a dense liquid, the drilling has followed the movements of the ice without fracturing for all these years.
The target is 2,750 meters below the surface, just before the bedrock, where the ice is thought to contain samples of our atmosphere over a million years old. That leaves 750 metres to go, and other competitors are in the race. “There are the Chinese, the Japanese, the Russians, the Americans and the Koreans. The Australians’ progress is the closest to ours,” explains Carlo Barbante, project coordinator for the University of Venice. “But it’s an honest and fair competition.”
Europe is in the lead, having worked on this type of drilling since the 1960s, and has held a record since 2006. An ice core has provided 800,000 years of continuous atmospheric records. “We’re strong in drilling, thanks to the Germans, the French, the Danes and the English,” explains the professor from Venice. And the same applies to the analysis of air bubbles archived in the ice.
At Little Dôme C, 16 people are busy extracting ice cores in 4-meter sections, between 8 a.m. and midnight. Two teams take turns. The drillers plunge the tube into the shaft until the head touches the bottom and cuts through the ice. The shavings are sucked into a chamber so as not to block the machine. Once grabbed, the piece of core is brought up with the drill by a cable under a large greenhouse. Scientists immediately take an ice extract from the profile to date the layers that have been traversed.
Last week, the core was close to 200,000 years old. The target is 1.2 million years, but the closer you get to the base of the core, the closer the periods get. “If the team succeeds, it will be a historic moment for climate and environmental science. What’s more, this success will enable us to focus the next and final campaign on duplicating the deepest part of the ice core and begin the closure of the Little Dome C camp,” says Carlo Barbante.
What’s so important between the 800,000 years already known and the 1.2 million years so sought-after? During this period, the Earth’s climate would have changed rhythm. The alternation of glacial and interglacial periods would have shifted from a 40,000-year cycle to a 100,000-year cycle. The origin of this upheaval remains unknown, but clues may have been left in the atmosphere, itself trapped at the bottom of the Antarctic ice cap.
The new cores will be transported to European laboratories for analysis. “The -50°C cold chain between the two hemispheres was a major challenge for ENEA’s logistics,” explains Gianluca Bianchi Fasani, logistics manager for Beyond Epica. Until the end of summer, the sections are stored in a trench under the snow in the camp.
Camille Lin, Polar Journal AG
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