11th January, 2013 and it is two months to the day since we left home in the UK. It is also the last week-end before uplift and we have spent the last week finishing the science programme and preparing to leave. The weather has reverted to bright sunny days with gusty winds of 25-30 km per hour blowing drifting snow around the tents. The highest temperature each day is around -10 C so, bearing in mind the wind, we are wearing a lot of clothes.
Talk is increasingly of what we are looking forward to when we get back to Rothera base. Top of the list is a hot shower. I think we are all shocked to realise that we have not washed our hair since 22nd November and that we have relied on a few wet wipes for all ablutions since then. The thought of shampoo in a shower of hot water is almost a fantasy. Next on our list is a beer in the bar, fresh fruit, food that you can chew, standing up straight indoors, and a flush toilet instead of a pee-bottle inside and pee-flag (bamboo stick) outside. A final item on the wish list is a new pair of socks for Scott! Socks excepted, it is strange how we have reached an equilibrium and that we no longer notice our state of hygiene.
The final week of science has been used to fill gaps, such as securing cosmogenic samples from high-elevation bedrock, installing a micro weather station to run for a year, measuring the altitude along the blue-ice margin, and re-surveying all the 90 stakes recording ice flow in order to see if there are any trends after two months. We also excavated a trench across a moraine ridge to check that there was a debris band there. There was!
A highlight of the week occurred on the day the weather changed to give us strong winds. Cirrus clouds formed as the winds blew over the mountains producing constantly changing patterns of waves, stacks of lenticular discs and funnel shapes like chanterelles, all brought to life by opalescent patterns around the sun.
Over dinner of our usual packet of Pack ‘n’ Go, we estimated that each skidoo has gone about 1200 km, making a total for the four of nearly 5,000 km, mostly commuting to and between the mountain groups. We have collected 280 cosmogenic samples, each weighing an average of 1.5 kilos, and aimed at dating a particular event. They now require two years’ work to process. We have run Differential Global Positioning Surveys (DGPS), accurate to cm, for some 50 km. We have installed 90 stakes in order to measure glacier flow that will be re-surveyed next season. We have over 15 km of Ground Penetrating Radar (GPR) over the ice and moraines, each one measured with a 3-second stop every 10 or 20 cm! We have high-resolution laser scanned maps of the main moraine system as well as of mountain fronts in six different locations. The successful flight of the remote-controlled plane has given us vertical photographs of the vital details of the surface structures in the main moraine system.
So what does it all mean? In a nutshell we can now begin to answer two main questions of process and evolution that underlie much of science, namely: What’s happening now? and What happened in the past? Applied to our project the questions are: What processes form blue-ice moraines? and How do they evolve over time? The link between moraine forms on the surface, structures in the underlying ice, and measurement of changes over the course of a year helps reveal the process of formation. The geomorphic mapping linked to cosmogenic dating will allow us to track the evolution of the moraines over Ice Age cycles and indeed over millions of years.
What are the implications for the Antarctic Ice Sheet? Well, blue-ice moraines certainly provide new insights into ice-sheet history and there is a lot to be gained from their study. So, now our thoughts have returned to the original question: Did the West Antarctic Ice Sheet disappear in the Last Interglacial? We are confident that we will be able to answer this convincingly. We have our hunch but must wait for the dating before we go public.