Million-year-old ice cores have already been found in Antarctica. But by finding them closer to the surface, the FROID project is hoping to reach the coveted ice samples more easily and at a much cheaper price.
On November 30th, 2024, four Belgian glaciologists arrived in Antarctica. With them, they brought a map of 10 drilling locations close to the Princess Elisabeth Antarctica Research Station and a plan of how to reach them within a month and half.
Each location was known to contain blue ice – compressed ice without a snow cover – and each of them had been handpicked for their potential to contain very, very old ice.
“We each had our favourite ice patch that we felt had the highest potential,” Maaike Izeboud told told Polar Journal AG.
Maaike Izeboud represents the Vrije Universiteit Brussels (VUB) who collaborated with the Université Libre de Bruxelles (ULB) on the FROID project. The project was funded by the Belgian funding agency BELSPO.
“We had tried to estimate which configuration of ice thickness, ice flow, and bedrock that was most likely to contain the old ice. But it was also more fun if everyone had their own favorite, so in the end the choices ended up being a bit random,” she said with a smile.
A couple of weeks ago, the researchers returned, having drilled out 15 test samples at the surface, each with the potential to be tens to hundreds of thousands of years old.
Their drilling locations had been carefully selected using a variety of parameters. And should this method succeed – the researchers don’t yet know if it did – it could markedly bring down the cost of ice-core based climate research.
“If we can find old ice in the way that we are exploring, then it could be drilled out in a single season. And if that’s possible, then it would give us access to many more samples which means more data on the ancient climate,” Maaike Izeboud said.
Old ice already found
Really old ice has already been found in Antarctica.
Around 9 years ago, the Beyond EPICA-project set out on the ambitious mission of finding the oldest ice ever found. And this year, they announced that their search had been successful: the pan-European research project had unearthed a 1.2 million year old ice core – the ever oldest continuous ice record.
But the Beyond EPICA project – which will conclude next year – is a mammoth effort, spanning multiple Antarctic seasons and costing a total of around 11 million Euro. This investment will likely be worthwhile, as it gives researchers a unique source of accurate data on past climates.
However, the data would be even more accurate, trustworthy, and, ultimately, useful, if it could be cross-checked with other data from the same period. Which is why looking for more easily accessible but still very old ice is interesting for the Belgian researchers.
Thankfully, this too has proven possible. In April of 2024, researchers from the American COLDEX-project revealed that they had found ice core samples as old as 4.9 million years – by far the oldest ever found in Antarctica.
“The COLDEX-project shows us that it is possible to find very old ice in areas with blue ice. But their samples were found in the Allen Hills on the opposite side of the continent, which is very far away. We are not yet sure if it’s possible in the area where we looked,” Maaike Izeboud said.
Meteorites indicate age of ice
The researchers are not searching blindly, though. Far from it. Areas with blue ice only make up around one percent of the surface of Antarctica so that already limits the search greatly.
Beyond that, when making their list of search sites, the Belgian glaciologists identified ice that:
- was moving slowly and was thus likely to have old, stagnant ice inside it,
- was situated above a certain typography likely to keep its lower layers still for millenia,
- was thinner than 200 meters and thus possible to drill to the bottom of in a single season.
Interestingly, they even took another Belgian research project into account. The ULTIMO project – recently profiled by Polar Journal AG – is looking for meteorites on Antarctica’s vast ice sheet, and, it turns out, it might also give clues on where to look for old ice.
If meteorites that are hundreds of thousands of years old are discovered on the surface, the ice it is found on is likely to also be very old, the researchers reasoned. Therefore, 3 out of the 10 locations they had chosen to drill at this season, also included sites where meteorites had been found by their colleagues two years prior.
“We recently had those meteorites dated and they were between tens to a hundred thousand years old. In theory this should be the lower limit for the age of the ice, but it isn’t necessarily reliable as meteorites can be moved by the wind, so we can’t be completely sure that their ages reflects the age of the ice at that location,” she said.
Samples still not dated
In the end, the FROID project brought back 15 ice cores, sampled from 9 out of the 10 pre-selected areas. One area proved to be located on too steep of a slope, making drilling there impossible.
But it will take a while to determine how successful their hunt for old ice was. Because, while the four researchers are now safely back in Europe, the samples are travelling slower. To keep them frozen, they need to be shipped to South Africa before being sent for analysis to labs in France and China. There, by dating atmospheric gasses locked in their air bubbles, the age of each sample will be determined.
“We have two or three samples that we think are promising but whether they will turn out to be old, remains to be seen. This is a new area of research so a lot is still uncertain,” Maaike Izeboud said.
She expects the samples to have been dated in about six months.
But once this year’s samples have been dated, it will only be a first step. For logistical reasons, the ice cores were only drilled out of the ice about 10 meters into it. To get to the very old ice that the researchers are hunting for, they will have to return to sites with promising samples and dig even deeper.
“When you only know the age of surface ice, there’s no guarantee how old the bottom will be. You only know that it will be older, but not by how much. But the age of the ice tends to increase exponentially as you get closer to the bottom. The bottom is where the ice has really been worn-down, squeezed, and compressed. That’s where you will find the really old ice,” Maaike Izeboud explained.
So how old should the ice be for the project to have been successful? Well, so far Maike Izeboud and her colleagues remain cautiously optimistic.
“We hope that we found some very old ice, but we also want to temper expectations a bit. I don’t think it’s likely that we will find ice that is two or three million years old. If we found one million years old ice, that would be a dream, and ice that is 100,000 years old at the surface would be a really good start,” she said.
Ole Ellekrog, Polar Journal AG
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