Drilling has begun in Australia’s quest for the oldest, continuous ice core record of Earth’s climate, dating back more than one million years.

Australian Antarctic Program scientists are on location at ‘Dome C North’ – a mound of ice in East Antarctica that ice-flow modelling and radar data shows may contain ice up to two million years old.

Over the past two years, teams have prepositioned equipment and drilled test cores at a nearby site.

Now, drilling at Dome C North has begun in earnest, to retrieve the most detailed continuous record of how the Earth’s atmospheric composition and climate have changed over centuries.

Palaeoclimate scientist Dr Joel Pedro is leading the Million Year Ice Core (MYIC) project team, who will use a drill, built in Hobart by the Australian Antarctic Division, to extract ancient ice from three kilometres beneath the Antarctic ice sheet surface.

“Bubbles of air that became trapped in the ice as snow fell, along with trace levels of natural and man-made chemical markers, provide us with the most detailed record of how the Earth's atmospheric composition and climate have changed through time,” Dr Pedro said.

“This information is pivotal to our understanding of climate and our ability to predict climate in the future.

“This includes helping to answer a long-standing puzzle of why, before about one million years ago, there was a change in the state of the Earth’s climate system to shorter ice-age cycles and smaller ice sheets.

“Capturing this record requires more than three kilometres of drilling, and we’ll tackle this over multiple summers.”

Identifying the ideal drill site was the result of years of collaboration between Australian, European and US science teams, collecting and sharing radar imagery from extensive ground and aerial surveys of the ice sheet, along with modelling expertise.

Traverse support

Reaching and setting up a camp at the site was also no small feat. A ‘tractor traverse’ team of 11 people, travelled 1200 kilometres from Australia’s Casey research station.

Using two snow-groomers, and six tractors towing sleds carrying 62 tonnes of equipment and supplies, the team travelled 18 days, through blizzards, heavy snow and sastrugi, via a route established last year.

“We planned to drive around 80 kilometres per day but at one point there was so much soft snow we could only manage 20–30 kilometres in 10 hours,” diesel mechanic Nate Payne said.

“We had to drop some of the payload, to collect later, and join three tractor trains together just to keep moving forward.”

The traverse team rendezvoused with the scientific team at Dome C North, and together spent two weeks constructing the camp site and drilling shelter.

The drilling team also honed their drilling skills and strategic approach for the “main drill effort”, by collecting ice core samples from 60 metres depth using a smaller ice coring drill.

“The energy has been high as we have rapidly moved from stage to stage to achieve the construction and science goals, and of course there’s a whole team back in Australia and at Casey station that has helped make our progress this season possible,” Mr Payne said.

International effort

The start of Australia’s drilling effort comes as European collaborators announce the retrieval of a 2800 metre-long ice core, containing ice up to 1.2 million years old.

The Beyond EPICA Oldest Ice Project has been working at Little Dome C, about 50 kilometres from Dome C North, since 2019, as part of an international effort to recover multiple, ancient ice core records.

“This is an exciting time for ice core science and we congratulate the European team on their achievement,” Dr Pedro said.

“Deep ice core drilling often involves work between multiple nations, and we have a close collaboration with the Beyond EPICA team on parts of our logistics and science.

“This includes acquiring multiple ice core records extending beyond one million years, for joint replication and verification.

“Collaborative modelling and radar work indicate that we’re well placed to build on and extend the European results, with an ice core that is older and more highly resolved.”

Pilot drilling

By the end of January, the ice coring team aims to have drilled a 150 metre-deep pilot-hole for the main drill, and extracted ice cores containing the most recent 4000 years of climate history.

In subsequent seasons they will aim to drill between 600 and 1200 metres of ice core each year.

By the summer of 2028-29 the team expects to reach the target depth of about 3100 metres and the scientific ‘treasure’ at the bottom of the hole – ice more than one million years old, and potentially up to two million years old.

The Australian Antarctic Division’s Science Branch Head, Rhonda Bartley, said that this year’s efforts would lay the foundations for successful deeper drilling in the years to come.

“The information the team collects will not only help us understand how the climate has changed in the past, but also more accurately predict what might happen into the future,” she said

“It’s very important that this season the drill team conduct their pilot drilling with care and precision, to ensure they can drill the best quality ice core in future seasons.”

The science team will fly back to Casey from nearby French-Italian Concordia station when the drilling season ends in late January.

The traverse team will return via their earlier route with the precious ice core cargo in specially designed, super-insulated containers.

The cores will then be flown by C17 to Australia, for analysis back in the Australian Antarctic Division’s ice core laboratory.

Read more

  • Learn more about the MYIC project in our interactive feature, Secrets of the Ice, published today.
  • Learn more about our traverse capability in our interactive feature ‘Ice Nomads’.
  • Read the MYIC team’s Drilling Diary.
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