Under the ice
Our campsite with the stunning Ellsworth mountains in the background. The location of equipment is always marked by flags in the event of snow covering everything. The Twin Otter plane passed by to bring us some supplies and spares.
By Rebecca Schlegel
Landscapes in deglaciated areas are like time machines. By looking at the shape and size of landforms, interpretations about the former ice flow processes can be made. Wherever you see a drumlin (an elongated, teardrop shaped hill) you know a fast-flowing glacier used to be here. But how did they form and what can that tell us about present-day and future ice dynamics?
With ice flowing at more than one metre per day, Rutford Ice Stream in West Antarctica counts as fast flowing, and its bed is laced with elongated landforms. My NERC-funded PhD research (part of the BEAMISH Project – Bed Access, Monitoring and Ice Sheet History) is about understanding the link between these landforms and actual ice stream dynamics. With this goal in mind, during the Antarctic field season 2017-18, I spent ten weeks on the Rutford mapping these landforms through 2.2 kilometres of ice using ice-penetrating radar.
On 13 December 2017, the Twin-Otter plane dropped my colleague Andy Smith (British Antarctic Survey) and myself off with lots of food, fuel, radar equipment and two snowmobiles on the Rutford in the middle of a snowstorm. We couldn't see much of the landscape until the next morning, when I started to realise that for the next ten weeks there would be nothing but two glaciologists, surrounded by the massive Ellsworth Mountains to one side, and a flat snow surface, stretching as far as the eye could see, on the other.
Rebecca Schlegel is studying for a PhD in Glaciology at Swansea University.
At first, ten weeks seemed like a lot, but they flew by. Time has another dimension in Antarctica – an example of this is making tea. You first have to get some snow, get back into the tent, melt the snow, boil the water, and then prepare tea. Although you save a lot of time not showering for ten weeks, every-day life essentials take about 30-50% longer than in the UK.
A typical day involved over eight hours of dragging the radar system behind the snowmobiles, at temperatures of around -25°C, with visibility varying between five metres and hundreds of kilometres, sometimes giving us stunning mountain views. With more radar data ‘in the bag’ we were happy to crawl back into the tent and have some freeze-dried morsels (my personal favourite was Chicken Korma).
Since cooking is time-intensive and supplies limited, goodies were few, but we treated ourselves with chocolate and olives for Christmas and New Year. As a highlight, on Christmas Eve, people from the British Antarctic Station, Rothera, called us to sing Christmas carols on the radio. People on the station did a fantastic job keeping us up-to-date with the outside world.
With 24 hours of daylight it felt as if time stood still, the only signs of time passing were the sun circling in the sky, weather changes and the fact that the location of our camp changed with the one metre per day ice flow. We were on our own personal conveyor belt and got to see the stunning mountains from different perspectives over the weeks.
Ten weeks with just two people in a tent requires a lot of humour, or even craziness. If we ran out of topics to talk about Andy tried (unsuccessfully) to teach me a Scottish accent, which is challenging considering that I am a German native speaker!
Happily, the work we did in these weeks was more successful than my new accent, and the high–resolution 3D images of the landscape under the ice will help to understand the subglacial process better. All in all it was one of my biggest adventures of my life so far and I hope there will be more to come!
The BEAMISH (Bed Access, Monitoring and Ice Sheet History) project aims are both academic and practical. The overall goal is to find out how Rutford Ice Stream has changed in the past and is flowing today. To do this scientists:
- Drill access holes to the bed of Rutford Ice Stream
- Sample and instrument the bed, ice and surface
- Find out when the ice sheet last disappeared
- Measure the temperature and straining of the ice
- See how water and sediment under the ice allow it to move fast
The project aims to improve our understanding of two aspects of this uncertainty: first, the past behaviour of the West Antarctic Ice Sheet (WAIS), and second, the flow of the fast ice streams that drain it. By choosing the right location, both these aims can be addressed within one project.
When completed, the project will give information on:
- An age for the most recent collapse of the ice sheet in this region
- The water system beneath the ice
- The thermal regime of the ice and bed
- The partition of ice motion between the three different flow mechanisms – sliding, ice deformation and bed deformation