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The hunt for planet Earth's oldest ice

16 October 2008

The hunt is on for the oldest ice on the planet - and the underlying reasons for a mountain range the size of the Alps deep beneath Antarctica. Polar scientists say the range defies 'any reasonable geological explanation'.

Scientists standing in front of an aeroplane

But scientists from the British Antarctic Survey (BAS) believe the valleys and ravines of the Gamburtsev subglacial mountains harbour the oldest ice on the planet.

If scientists can reach the range - the foot of the range looks likely to lie four kilometres below the surface - they will have ice that is more than 1.2 million years old. Locked in this ancient ice is a detailed record of past climate change. The more knowledge scientists have of how climate changed naturally in the past, the better researchers can predict the future.

Intriguing rumours from Russian researchers suggest some of the mountain peaks are very shallow, perhaps 100 metres below the ice surface. But no one has access to the original Russian records.

Map of Antarctica

CLICK TO ENLARGE. The Antarctic Ice Sheet. The Antarctica Gamburtsev Project (AGAP) is setting up two field camps AGAP A and AGAP B.

In November, a large international team from the UK, the US, Germany, Australia, China and Japan will set up two remote field camps above the mountain range.

During the operation the polar scientists will do between 80 and 100 surveys using research aircraft to build a picture of what lies beneath the ice. The work is part of the massive International Polar Year (IPY) initiative which involves 60,000 scientists from 50 countries and whose international office is funded by the Natural Environment Research Council.

'It is a bit like preparing to go to Mars,' says geophysicist Dr Fausto Ferraccioli from the British Antarctic Survey. 'IPY scientists are working together to do the unthinkable, to explore the deep interior of East Antarctica - one of the last frontier regions of our planet.'

Schematic of survey.

CLICK TO ENLARGE. How the team plan to survey the mountain range.

Airborne radar will map ice thickness, ice layering, the terrain below the ice and subglacial lakes. Other aircraft instruments will look at the underlying geology and give an idea of the crust thickness beneath the mountains.

The mountains were discovered using seismic sounding equipment in 1958 by a Soviet Antarctic expedition and named after Grigoriy Gamburtsev, a Russian geophysicist, during International Geophysical Year.

They are positioned deep in East Antarctica, lying below the highest, and perhaps the coldest, place on the East Antarctic Ice Sheet - Dome A. The range could be the birthplace of the vast ice sheet.

The mountains are unusual because they are situated in the heart of Antarctica. Ranges like the Himalayas, Andes and Rockies form when continents collide; crunching tectonic plates force rocks skyward. This explanation does not fit easily with what polar researchers know about the Gamburtsev range.

Mountains can also form above volcanic hotspots like Hawaii, but so far, no volcanic activity has been found in the region.

'We really can't understand what these mountains are doing in the centre. It really is an enigma,' says Ferraccioli.

'There is no supporting evidence for hotspots.'

But he adds that seismic instruments that can measure these deep geological features are situated on the edges of Antarctica. It could be that they are too far from the mountain range to pick up the tell-tale signs of hotspot activity.

Radar equipment on wing

The ice penetrating radar attached to the Twin Otter aircraft wing.

The team plan to install 20-25 seismic instruments above the range.

The programme, called Antarctica's Gamburtsev Province Project and scheduled to last two and half months, will be the first major geophysical survey to map the landscape beneath the vast ice sheet. Depending on the outcome of the survey, drilling ice cores could start in a couple of years.

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Your comments

I am curious why BAS should think the "world's oldest ice" (1.2 Ma) might occur near the Gamburtsev Mtns. To put the record straight, 1.2 Ma ice (even should it exist at that location) would not be the world's oldest. Ice approximately 8 m.y. old has been documented from the Dry Valleys (Sugden et al, 1995, Nature 376, 412-414; Schafer et al., 2000, EPSL, 179, 91-99). Attributing the "world's oldest ice" to the Gamburtsevs may be due to a fixation with considering only that ice recoverable through ice coring.

john smellie, Cambridge (BAS HQ)
Tuesday, 1 December 2009 - 15:33


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