A team of European scientists heads to East Antarctica to locate the oldest ice on Earth. The team’s goal is to search for a suitable site to drill an ice core to capture 1.5 million years of Earth’s climate history. Such a core will answer important questions about big shifts in the past record of Earth’s climate and ultimately improve our knowledge of future climate.

In their quest for the oldest ice, researchers will survey a new site Little Dome C, which is located 50 km away from the French-Italian station of Concordia, based at Dome C, where the longest ice core so far was drilled.
In their quest for the oldest ice, researchers will survey a new site Little Dome C, which is located 50 km away from the French-Italian station of Concordia, based at Dome C, where the longest ice core so far was drilled.

Scientists from ten different European countries are currently looking for a site in Antarctica where an ice core could be drilled that contains a continuous record of the last 1.5 million years climate history.  Currently, the oldest ice core goes back 800,000 years. This EPICA ice core was drilled at Dome C in East Antarctic in 1996 till 2004. EPICA stands for "European Project for Ice Coring in Antarctica". The new project "Beyond EPICA - Oldest Ice" (BE-OI) hopes to find 1.5 million years old ice, which could be drilled in future.

The ice becomes more and more transparent as drilling depth increases. The ice appears milky grey as a result of air bubbles up to a depth of 1,000 m. Below 1,200 to 1,300 m depth, the ice is transparent like Plexiglas. (Photo: Sepp Kipfstuhl, AWI)
The ice becomes more and more transparent as drilling depth increases. The ice appears milky grey as a result of air bubbles up to a depth of 1,000 m. Below 1,200 to 1,300 m depth, the ice is transparent like Plexiglas. (Photo: Sepp Kipfstuhl, AWI)

Ice cores are climate archives, containing air from the past. Through laboratory analyses of the air the past composition of the atmosphere can be revealed. It is also possible to deduct past temperatures on Earth at the time the snow fell. The investigation revealed that ice ages came and went on a roughly 100,000-year cycle. This changed, however, further back in Earth’s history. “We do not know, why there was a change in the glacial-interglacial periodicity 900,000 to 1,200,000 years ago”, explains BE-OI project coordinator Prof Olaf Eisen, glaciologist at the Alfred Wegener Institute (AWI).

Before this so-called mid-Pleistocene transition glacial and interglacial periods took turns about every 40,000 years. Since then this cycle is about 100,000 years. This knowledge originates for example from sediment cores. However, since they do not contain atmospheric gases “we cannot specifically investigate the role of greenhouse gases, because we do not have suitable samples”, says Prof Frank Wilhelms, AWI glaciologist and subproject leader.

Research aircrafts like Polar 6 will be used in Antarctica. With their help, the topography under the ice can be determined. (Picture: Martin Leonhardt, AWI)
Research aircrafts like Polar 6 will be used in Antarctica. With their help, the topography under the ice can be determined. (Picture: Martin Leonhardt, AWI)

BE-OI is supposed to change that: The project includes geophysical measurements, rapid drilling technologies and age determination of ice on site. In addition, required drilling technologies will be developed further and tested. The first hands-on work will be starting shortly: In Antarctica glaciologists from the Alfred Wegener Institute AWI together with European BE-OI partners will investigate the ice sheets’ thickness, its physical properties and the topography of the underlying bedrock at two different sites from an airplane as well as on ground. Ice thickness is just a first indicator of past ice, as different snow accumulation and ice flow behaviour determine, how thick the ice sheet is today.

The researchers, together with other BE-OI partners, will investigate the ice sheet’s thickness, its physical properties and the topography of the underlying bedrock at two different sites (Dome C and on the East Antarctic plateau at Dome F). Ice thickness is just a first indicator of past ice, as different snow accumulation, ice flow behaviour and the temperature at the bottom determine whether old ice remains near the base of the ice sheet. (Picture: BAS)
The researchers, together with other BE-OI partners, will investigate the ice sheet’s thickness, its physical properties and the topography of the underlying bedrock at two different sites (Dome C and on the East Antarctic plateau at Dome F). Ice thickness is just a first indicator of past ice, as different snow accumulation, ice flow behaviour and the temperature at the bottom determine whether old ice remains near the base of the ice sheet. (Picture: BAS)

On the ground scientists will simultaneously measure snow accumulation and will use new technologies, to drill boreholes and determine temperatures. “During previous studies we determined key regions, where we expect the oldest continuous ice record on Earth” says Olaf Eisen. Preliminary studies for the location selection of the ice hole took place around the Dome C and Dome Fuji in the East Antarctic. “Now we have to prove this and it is important that we learn as much as possible about deposition processes and the composition of the ice”, explains the glaciologist.

Besides answering scientific questions, the project aims to assemble technical and personnel expertise for such a deep-drilling project, to set up a science and management plan and to establish the budget and funding. In order to gain a maximum of scientific knowledge, the wider paleoclimate community and the modelling community will also be included.

BE-OI is the European contribution for the global search for a suitable site for an ice-core deep drilling and is funded by the EU with 2.2 million Euros.

Source: Alfred Wegener Institute for Polar and Marine Research