Field Update: Jan. 2, 2011

Overcast skies and the resulting helicopter hold due to waiting on weather was today’s story. The geophysical team members were all waiting in McMurdo for a chance to get out to the ANDRILL camp, but it became clear as the day progressed that the weather window was not going to open up – too much fog on the ice to allow helicopters to fly.

I’ll now return to some of the other science activities that took place this season that I haven’t reported on yet. One of these was the gravity survey conducted by Gary Wilson, Daniel Jones, and Chris Stubbs during early December, which ran along the marine seismic line 1A0 (see below).

Gary Wilson is a geophysicist from the University of Otago in New Zealand. He brought a geography student from Otago with him, Daniel Jones, as well as a recent graduate student from the University of California, Santa Barbara, named Chris Stubbs who took the pictures shown in this blog.

The gravity survey involved snow machines towing sleds that had an accurate GPS antenna and receiver, and a gravimeter using springs, weights and accelerometers mounted in a small box to measure gravity at each spot.

The gravity survey stations were spaced 500 meters apart along line 1A0.

The team stopped at each station to make measurements and then moved on.

Each measurement required the gravimeter to be placed on a small round pedestal mounted on a piece of plywood and leveled carefully.

The gravimeter was left in place for approximately 30 minutes to collect enough data to ensure that the measurement was accurate. The line was about 70 kilometers long from one end to the other, so it took several days, and the measurements required good weather with light or no wind, so there were several days when no measurements could be taken.

Thankfully, Russell Freeman was back at camp cooking great meals and making gourmet desserts that gave everyone involved in the survey the energy they needed to keep going back out into the cold to get the job done!!

The gravity team finished their work on December 16th and went on to other tasks. Chris stayed at camp to help with the preparations for the seismic refraction survey that would take place in late December to early January. Gary joined Richard Levy and Tim Naish to fly to the Central Transantarctic Mountains (CTAM) to conduct additional fieldwork on the Beardmore Glacier, and Daniel carried the gravity data and the equipment back to New Zealand so that other people could continue to work with this equipment.

Meanwhile, the daily work continues at the ANDRILL Coulman High camp - - more about that in tomorrow’s blog!

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