In order to better understand the Earth's past and thus have enough information to anticipate the future, researchers are crisscrossing Antarctica in the hope of finding the oldest ice in the world .
The oldest ice on Earth is probably buried somewhere in Antarctica, argues Nell Greenfieldboyce of Npr.org . Some of the layers of ice found in this continent have witnessed events that have taken place on the blue planet for thousands, if not millions of years. Convinced that it will find the oldest ice in the world in this region, a team of scientists is carrying out a project whose goal is to bring to the surface such a rare pearl. John Higgins, a geochemist at Princeton University, is part of the said team.
He says researchers don't yet know the exact age of Antarctica's oldest ice, although theories suggest the continent has been teeming with such material for around 30 million years. .
Dating from bubbles trapped in ice
Before Higgins and his colleagues, another group claimed to have collected 8 million year old ice. To establish this age, he dated a sample of volcanic ash present in the ice. A technique that does not seem to be unanimous in the scientific world.
“I don't know if it's exactly 8 million (years), but I accept that it's old ice,” said Eric Wolff, climatologist at the University of Cambridge in the UK, for example. . This scientist considers it best to perform the calculation based on the bubbles trapped in the ice.
Ice 2.6 million years old
This method advocated by Wolff is the one Higgins and its partners use. “When you look at the ice, it's apparently crystal clear, except it's filled with tiny bubbles,” he explains, as quoted by Npr.org. And it turns out that these little bubbles are “a time machine”.
The team recently drilled an ice sample in the Allan Hills region of Antarctica. By analyzing the air bubbles that were inside, she managed to determine the age of the small block: 2.6 million years. Another younger sample, apparently 2 million years old, has been found nearby.
In a purer state, the latter exhibited traces of carbon dioxide and methane. And this discovery is not trivial. According to our source, "understanding how carbon dioxide levels have changed over the course of Earth's history could help climatologists understand how human activities will warm the planet in the future . "