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2007
Date: November 28, 2007
Location: East Antarctic Plateau, On the road
Latitude: 83 degrees, 43 minutes, 7.32seconds South
Longitude: 138 degrees, 1 minutes, 22.62 seconds East
Temperature: −32°C ( −26°F)
Wind Speed: 8 knots
Wind Chill: −59°C (−73°F)
Elevation: 2619 meters (8593 feet)
Kilometers Traveled: 462
Ice Core Drilled: 95 meters
Written by: Dan D.
After a long day of driving (at a constant speed of 8 kph (~5mph)), we finally stop for an eight hour rest in what can only be described as a snow pyramid field! We are completely surrounded by pyramid shaped mounds of snow and ice as far as the eye can see. We have passed through a couple of these strange looking fields throughout the day and they do not make for a smooth ride. It is very hard steering the traverse trains through without hitting any of the mounds. Most of the mounds are under 50cm tall and do not really pose much of a problem. However, some of the mounds can be over 1m tall and can cause quite a bump if the trains go over them.
Upon arriving at the rest stop, Paul and I walked a few hundred meters upwind of the camp to collect some fresh surface snow samples for chemical analysis. On the way back from sampling we were discussing these strange pyramid shaped mounds and I said ‘I wonder how hard these things are?’ I then proceeded to give one of the larger mounds a good kick on its windward side and was surprised to see that it didn’t even leave a mark (I was also shaken by the fact that I had just kicked an immovable object quite hard). Undeterred, I tried kicking the leeward side of the mound. To my further surprise, my foot completely disappeared inside the mound! I jumped back and peered inside, the mound was hollow.
We explained our findings when we got back to camp and Dan B. and Nicky wasted no time in investigating further. They took a shovel and snow saw out and began decapitating several of the nearby mounds, they all turned out to be hollow. Careful inspection of each mound revealed that a firn crack passed across the nose of each and every one. Firn cracks are formed as the wind blows through the loosely consolidated upper meters of the ice sheet surface (the upper part of the ice sheet surface is called firn). The air on the East Antarctic Plateau is so dry that as the wind blows through the firn, the snow crystals sublimate and eventually form conduits, pathways of least resistance, through the layers. After hundreds, and quite possibly thousands, of years of this process the firn in this area of the ice sheet resembles something like thousands of layers of crazy-paving stacked upon one another – but instead of concrete and mortar between the paving slabs, there is just empty space where the dry air has sublimated the firn away.
After much discussion between traverse members, the hypothesis we came up with is that these pyramid shaped features form over the firn crack ‘exhaust ports’. The sublimated vapor (from inside the firn cracks) is probably recrystallizing upon contact with the atmosphere and the wind then sculpts the recrystallizing vapor into pyramid like shapes. Pretty Cool!
Date: November 29, 2007
Location: East Antarctic Plateau, Drill site 2
Latitude: 84 degrees, 23 minutes, 42.252 seconds South
Longitude: 140 degrees, 37 minutes, 50.88 seconds East
Temperature: −28°C ( −18°F)
Wind Speed: 6 knots
Wind Chill: −37°C (−35°F)
Elevation: 2687 meters (8815 feet)
Kilometers Traveled: 542
Ice Core Drilled: 95 meters
Written by: Nicky
In the midst of all our driving, something interesting happened early this morning. Elena and I (separately, of course) decided to take a spin in Brian's radar sled. Could we hack it? Yes and no. Elena made her way through an entire waypoint (although rumor has it that it was the flattest 10km since West Antarctica) and has offered her able assistance during future runs. I, on the other hand, started to feel a little funny with 4km to go and was fortunate enough to experience a radar stop (which I used as an opportunity to jump off the radar sled and into my less bouncy bed in the kitchen).
In other happenings, we arrived at the second drill site at 10am, thoroughly checked the radar to ensure uniform stratigraphy, quickly set up camp (perpendicular to the wind!) and then promptly put ourselves to bed. The day was spent sleeping, an activity that was only interrupted by an equally rigorous hot meal and movie. After all, tomorrow we start drilling again and we’ll need our strength.