Dynamics of the Blue Ice Regions in Antarctica
Dynamics of the Blue Ice Regions in Antarctica
Andrei Kurbatov, Leigh Stearns,
Vandy Blue Spikes
John Moore, University of Lapland
January 10, 2004 to February 20, 2004
An earlier award to Drs. G. Zielinski (UMaine) and N. Dunbar (New Mexico Tech) resulted in the collection of ‘horizontal ice core’ at the Mount Moulton blue ice field in West Antarctica. Preliminary analyses of the sample material suggests that a ~500 kya climate record is preserved in the ice at this site. This project seeks to contribute to the understanding of the Mt Moulton record by assessing the potential for ice-flow induced deformation of the stratigraphic profile. In addition, this proposal builds on the recognition of blue ice areas as archives of long climate records by conducting reconnaissance studies for a potential horizontal ice core location at the Allan Hills in East Antarctica.
The objectives of this project are to contribute to the glaciological understanding of blue ice areas in Antarctica. Specific goals are to:
- Study ice flow conditions at the Mt Moulton blue ice field to assess the possibility that the stratigraphic record has been deformed;
- Conduct reconnaissance of a potential horizontal ice core site in the Allan Hills blue ice field.
Short field programs will be undertaken at each location to collect relevant measurements of ice flow and subglacial topography, and conduct sampling of material that will enable the preservation of the stratigraphic sequences to be assessed.
Leigh writes from McMurdo:
We all made it to McMurdo after only one flight delay from Christchurch (a record for me!). The weather here has been spectacular – surprisingly warm and clear. Today it’s 20°F, with hardly any wind – temperatures so warm that our Maine friends think we might as well be in Florida with lawn chairs and cocktails. The weather at our field sites promises to be much colder and windier.
John and Andrei spent the last two days at ‘Happy Camper’ School where they were taught how to put up a tent and light a stove. These courses are required for people who are ‘new’ to the ice. We got a big kick out of the fact that John had to attend, even though he’s been to Antarctica several times with the Finnish Group and teaches similar snow survival courses in Scandinavia.
While John and Andrei were at snow school, Blue and I were busy getting gear, food and fuel together. We are due to head to Mt. Moulton on Monday, for about a week (weather permitting). Mt. Moulton has notoriuosly bad weather. The science group that’s there now were delayed almost one month, waiting for good weather and flight logistics. We will fly by LC-130 to the base of Mt. Moulton where we’ll set up camp for one night in order to acclimatize. After 24 hours, we will go up to the blue ice area via Twin Otter.
Blue writes from McMurdo:
After gathering all our gear in McMurdo, our four person field team boarded an Air National Guard LC-130 aircraft on January 13. The 1,400 km flight to the base of Mt. Moulton took just under four hours. Upon our arrival, we were greeted by another six person field team led by Nelia Dunbar of New Mexico Tech. Dunbar’s group had just spent five weeks at the summit of Mt. Moulton collecting ice and rock samples, which should help them interpret the horizontal ice core they collected in 1999.
Our meeting with Dunbar’s group was not a chance encounter. It was a carefully planned attempt to conserve logistics, and it would have worked out splendidly if the weather had cooperated. Unfortunately, the Twin Otter (small aircraft with dual turbo props) that had just transported Dunbar’s group from the summit of Mt. Moulton could not transport our group back up to the summit, because low clouds had moved into the region. Low clouds make it dangerous to fly in mountainous terrain, especially while landing. In addition, the LC-130 that was supposed to take Dunbar’s group back to McMurdo for a much needed break from the harsh environment, was also unable to fly because of its heavy load and soft snow conditions. So all nineteen of us (including the four of us, the six people in Dunbar’s party, the three person crew from the Twin Otter, and the six person crew from the LC-130) spent the night together in what we later learned was the biggest field camp in West Antarctica. Despite the fact that none of us were where we wanted to be, we did manage to put together a very nice barbecue before heading to our tents for the evening.
The situation improved slightly the following day as Dunbar’s crew was able to fly out on the LC-130. Unfortunately for us, the low clouds forced us to wait another day before heading to the summit. We finally made it to the summit on the 15th of January, and found that the Dunbar team had left us a very tidy camp, so we went straight to work. Andrei busied himself setting up our electrical and communication equipment, which consisted of four solar panels, one battery, several VHF radios, and an Iridium phone. Leigh went to work setting up the GPS base station, which was also powered with a solar panel and battery. John set up his ice penetrating radar system, which was designed to detect the ice thickness (up to 1 km) and map the subglacial bedrock topography. I spent my time putting together a second ice penetrating radar system, which was designed to detect isochronal layers that we will use to estimate snow accumulation rates.
We began conducting radar surveys the following day. Leigh and Andrei helped John with his radar unit. Andrei drove the snowmobile, John manned the radar control box, and Leigh kept the whole system in a straight line. It appeared that Leigh had the hardest job, because she was constantly running behind the snowmobile. I may have had the easiest job, because the shallow radar unit was quite small and easy to use, so I was able to drive the snowmobile and run the radar control box at the same time.
We continued our work at Mt. Moulton for the next 8 days. Leigh and I conducted GPS surveys to determine the surface topography and measure ice velocities, John tested his Electronator (an electrical device used to measure the conductivity of the ice), and Andrei studied the volcanic tephra layers that outcrop on the blue ice surface.
Overall, the site was a good one. The temperature was consistently around -15 to -20° C. The wind was generally calm, and when it did blow, it was almost always from the North. The sky was generally overcast, though we did see blue skies on several occasions. The view from camp was outstanding, because we could see Mt. Berlin (an active volcano) towering above us to the West (~20 km away), and the West Antarctic Ice Sheet stretching out below us to the South.
On January 24, we packed up our gear and waited for the Twin Otter to arrive and move us to the base camp where we would wait for the LC-130 that would take us back to McMurdo. Sure enough the Twin Otter arrived in the morning. Unfortunately, the LC-130 schedule had been altered, and our group was forced to split up. I took the opportunity to fly to McMurdo on the Twin Otter, so I could work out the logistical plans for our next mission at the Allan Hills. Leigh, Andrei, and John were forced to wait for the LC-130. I am currently still waiting for my coworkers, but they are scheduled to arrive in a few hours.
Leigh writes from McMurdo:
Lather rinse repeat. Lather rinse repeat. repeat. repeat.
We are now all safely in McMurdo after 2 weeks at Mt. Moulton. John, Andrei and I arrived at 3:30am after spending 3 beautiful days at the base of Mt. Moulton, organazing our gear and waiting for our LC-130 plane to arrive. We were hardly in dire straits, but were down to our last shred of chocolate, had exhausted our recollections of Seinfeld jokes, and were going in circles with our discussions of religion and politics. Needless to say, we were glad to see our friends from the US Air National Guard in Albany.
We had a busy day organizing our cargo for the Allan Hills since we leave early tomorrow morning. Gear had to be fixed, cleaned and exchanged and then weighed, measured and packed. Apparently we broke the record for the fastest turnover of gear.
Despite the niceties that McMurdo has to offer (hot water, cozy beds, good
food), we are all eager to get back to the field to finish up our science objectives.
The team only had a short time in McMurdo before they headed home. Andrei was able to send some photos.Click on a picture to see it full size.
Leigh is back in Maine and files this report on the field season:
I had to break this journal entry up into ‘The Science’ and ‘The Life’ because scientifically everything went smoothly – the difficulties came from everyday life activities.
Our objectives at the Allan Hills were similar to those at Mt. Moulton – to study the ice flow and gather information for a potential horizontal ice core (refer to our projects page). Our tasks are outlined below:
- Mapping: The first 3 days were spent mapping the area so that we could figure out the topography and, consequently, the direction of ice flow. With GPS antennas attached to the snowmobiles, we drove around in grids and then zigzags to collect as much data as we could.
- Ice Flow: After we mapped the area and got a general idea of the ice flow direction, we installed ~20 ice velocity poles – 3m conduit pipes drilled into the ice. We determine their exact position with GPS and then resurvey them in the future to measure their displacement. The poles that we installed expanded an already existing network of poles that Blue installed in 1997 and that he and I resurveyed in 1999.
- Ice Core: Accumulation rates are an important variable in glaciology, yet they are difficult to measure. The method that we use is called beta counting. We try to identify radioactive horizons within the ice core (using a beta counter back in Maine) – namely 1955 and 1964 bomb tests. If we know the age of the ice at a certain depth we can deduce what the average accumulation rate for the area is.
- Radar Mapping: While Andrei, John and I put in the ice flow poles and collected the ice core, Blue collected radar data. The shallow radar is a small unit and can be easily dragged behind a snowmobile. There is already a bed topography map of the Allan Hills, so we didn’t need to do any deep radar mapping.
- Tephra Mapping: There are a couple of pictures of me and Andrei mapping the tephra layers. While I mapped the layers, Andrei collected tephra samples. These tephra layers were significantly smaller than the huge ones we saw at Mt. Moulton.
- Electronator: There are many more tephra layers in the ice than the ones that Andrei and I mapped by sight. To try to locate these layers John used his ‘electronator’. Two electrodes are attached to a wood bar that we drag behind the snowmobile. As we’re driving, the electronator measures the conductivity of the ice. This is a new invention of John’s and we were excited to test it.
- Meteorites: We did collect a few meteorites while we were in the Allan Hills. These will be used to date the surrounding ice (through the radioactive decay of cosmogenic nuclides). Unfortunately we did not collect more because of time (and temperature) restraints.
Don’t be fooled by the sunny pictures you see on the website! We all agreed that the Allan Hills was probably the most brutal place we’d been to (this is coming from 4 people who have done extensive field work in Antarctica, Svalbard, Greenland, Finland and Kamchatka). It was beautiful, but the weather that late in the season was tough. The brisk temperatures (-24°C) and light breeze of the katabatic winds (30 knots) were relentless and made everyday living pretty difficult. Here are two examples:
- Task 1: get out of your sleeping bag
- Ignore the thin layer of ice that has coated your sleeping bag from condensation of your breath.
- Ignore the fact that you can hardly talk with your tent-mate because the wind is flapping the tent so loudly.
- Take contact lens case out of your hat. If contacts are defrosted put them in. If they are still frozen, stick them in your armpit.
- Pull insulated windpants over fleece pants over long underwear. Add two polypro shirts on top of your base layer. Put on down jacket. Put on Antarctic issue down jacket (yes, I did have two down jackets on!), two pairs of socks, boot liners and boots. Top it off with a turtle neck liner, wind-stopper balaclava, goggles and hat. Put on your gloves and mittens. Okay, now you’re ready to go outside.
Despite the tough weather, we all managed to maintain our spirits and stay focused on our science goals. It became quite amusing how persistent the bad weather was. Usually you get one or two days of weather like that an entire season…we had it for 10 days straight.