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Antarctic volcanoes punching holes in the ice

Black Mesa, a typical Mt Haddington Tuya. The top part is flat lava and the steep cliffs are the lava delta. 
Deeply-frozen Prince Gustav Channel that separates Mt Haddinton from the Antarctic Peninsula. This year ice was so thick that the Endurance could only get to within 40 miles of James Ross Island. Long Helicopter trips were needed to ferry the field parties onto the island. 
Rum Cove Camp, with GA Rob Smith. The camp, between two glaciers, was my home for two weeks and now holds two colleagues until they are picked up in six weeks time. 

Volcanoes in the ice

It seems odd at first to think of volcanoes in such a cold place, but to 1200°C-magma, rising through the earth, the cold of Antarctica is nothing. The frozen continent has many active volcanoes, and some like Mt. Erebus in Eastern Antarctica has a near-permanent lake of hot lava at its summit where air temperatures are well below zero. When the volcanoes erupt the lava pours into the ice sheet. Huge quantities of ice are melted around the eruption, creating lakes. If the lake breaches the ice sheet, a vast flood is liberated. These are called 'Jokulhaups' by Icelanders, who are well aware of the effects of such sudden inundations coming from their Vatnajokul ice cap. Apart from such terrible effect, the erupting lava is profoundly affected by the ice it melts. As lava rolls down the volcano it meets water. As lava flows hit the shoreline, lava balls and fragments tumble pell-mell into the lake. The shore line is built out by a delta of smashed-up lava covered with the advancing hot flows. The volcano gets a table mountain shape: a flattish lava top and steep rubble flanks. Such mountains are called Tuyas, coming from a Canadian Indian arctic word. Tuyas are found wherever volcanoes have punched through ice caps, but volcanoes that have erupted in the sea, such as Hawaii or the Canary Islands have similar shapes.

Tuyas and Climate change

With current concern about climate change, and especially the possible collapse of Antarctic ice, scientists are searching for ways of seeing how ice caps have varied in the past. Tuyas hold a magic card for this, as they record the ice level when the eruption happened. The Tuya's preserved shore line (the table edge) gives the ice level. Then all is needed is a sample of the lava to give the eruption date. Radioactive elements in the sample are a 'clock' that allows the date to be measured. Tuyas then tell you how thick your ice cap was, and if there are lots of Tuyas at different times, much of the history of the ice sheet can be worked out.

The Antarctic Peninsula is a bit like Britain for its changing maritime weather. Its climate is the most variable of all Antarctica, and the one that is showing fast warming. The ice cap that still smothers the peninsula has grown and shrunk rapidly over the last few million years in response to climate change. At the same time, there have been loads of volcanoes. Tuyas all over the place and rapid ice cap fluctuation are a key to understanding the climate of the past.

Mt Haddington: a super Tuya

The project I am involved with has been developed by John Smellie, a British Antarctic Survey volcanologist and world-renowned expert on volcanoes in ice. His idea is to use a 'Supertuya', the Mt Haddington volcano, on James Ross Island to find out the fortunes of the Peninsula ice cap over the last 10 million years. Haddington is a massive volcano over 50 km wide, which has had many many Tuya-like eruptions over this long time span. Some of its single eruptions are bigger in volume than an entire normal-sized volcano. Old eruption shore lines are found everywhere on the now deeply-eroded volcano flanks. These allow John to calculate the old ice levels. The actual work is hugely complicated and belies the simple explanation I have given here. Months of gruelling fieldwork has to be done to work out the whole history and this is backed up by several years of work in the laboratory. John has collected an team of experts to do the work: there is a glacier expert, Prof. Mike Hambrey from Wales; a researcher Jo Johnson working on how the volcanic rocks are altered in water. There is Magnus Gudmunsson, an Icelandic geophysicist with first-hand experience of eruptions in ice, and Prof. Ben van Wyk, (that's me). I work at Laboratoire Magmas et Volcans, at Clermont-Ferrand in the French Massif Central.

Deforming volcanoes

I am on this project because I work on volcano deformation. Volcanoes are growing mountains and as they grow, their weight folds and buckles the earth beneath. This has all sorts of consequences, changing the way it erupts, creating terrible volcanic avalanches. Most importantly for this project, shore levels can be changes as the volcano sinks. Obviously, if the important ice markers on Haddington have moved, then John Smellie's old ice cap levels will be wrong. My job is to prove the levels have either not moved significantly, or calculate their height change. I do this by looking at the rock beneath the volcano to see how it has been affected by the great weight. Haddington in underlain by several kilometres of squashy Cretaceous sandstones and mudstones, full of fossils from a time before the ice caps. This layer is being squeezed out from underneath, creating a squashed up range of hills that circle the volcano. My work has found that the volcano has sunk into the muck below it, but not by much, luckily it has behaved like a raft and has only settled a little. Now I have to go back to the laboratory and look under a microscope at my samples to see just how much squashing has been going on. Then I shall make miniature scale models of the volcano to calculate the level changes. But the firm conclusion of the project is good: the vital levels have only been slightly changed and the ice levels can be calculated.

I also have a hidden agenda: I said that Tuyas are like an oceanic island such as Hawaii, just erupted in a sea of ice. The difference is that Haddington now stands clear of the water. Unlike Hawaii, I can see the rocks that were underwater. Haddington is allowing me to look at submarine volcano flanks and understand how giant tsunami-creating landslides are triggered at other volcanoes.

The Endurance and Field work

The way to get to James Ross Island is by HMS Endurance. We were picked up by the ship in the Falklands and taken across the Drake's Passage to the Peninsula. Once near the Island the two Lynx helicopters took our gear and us onto the island. I camped for 2 weeks beside a glacier in a place called Rum Cove, and went out every day to search for my rocks. I worked with a 'GA' general assistant, an understated term for a superbly trained and experienced alpinist / polar guide. Rob Smith was my guide, a Scot from near Edinburgh, who had just come south after climbing North America's highest peak Mt Denali. The GA's call the scientists 'Beakers', probably after the Muppet character and there capability for getting too carried away and forgetting all about the dangerous place we work in. This prejudice is probably correct, however Rob kept me safe and alive, despite my urge to scramble around below the giant cliffs that encircle the volcano.

My trip was relatively short, but I parted with two other pairs on the island. They have been left for the next six weeks. Jo and Asty are in a tent at Rum Cove, and John and Rob are at a magical place called Hidden Lake, a deep valley surrounded enormous cliffs and glaciers. There should be a blizzard there now, and I know they will be firmly shut up in their tents, battered by the winds and laying low until the storm passes. Their main concern will now be keeping some water unfrozen and themselves warm. In a day or so they will emerge, dig the snow away and start the work again.

Work on the edge of existence

Their existence is extreme isolation, on the borders of what is possible to survive and to work in, but the safety system and back up is meticulous and long practiced: there is nothing foolhardy about our exploration. At the back of their minds will be the daily radio contact with the British Antarctic Base at Rothera, a brief link to the rest of the Antarctic world and the thought that in six weeks the Endurance will come back. Two years ago we were pulled out in a two daylong blizzard at the very end of the season. Winter was fast setting in and we had sat in the tent counting the days of food and wondering if it came to it, how long we could survive. It never came to it, and the helicopters arrived out of the storm to take us home. The Lynx helicopters, their excellent pilots and navigators, and the Endurance crew are a vital lifeline to the field parties. While they claim to be just doing what they are supposed to do there remains a great debt of gratitude that we on the ice feel towards them. They deserve the Icelander volcanic toast: 'here's Tuya!'

Read all the latest news about the ship's deployment by following the links below, with additional pictures in the Picture Gallery.. HMS Endurance Tracking Project pages