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Glaciologist Erin Pettit Reports from the Field

Glaciologist Erin Pettit Reports from the Field

We were a bit sad when Mike returned to pick us up; we decided we needed several days at Sunny Knob to really be able to explore the area. But we had drilling to do. We arrived back at camp close to 9 p.m. Doug and Bella had the ice core boxes in the net ready to fly home as a sling load because they wouldn't fit inside the helicopter. In order to attach the sling, Eric stood on the snow near the boxes and Mike maneuvered the helicopter down on top of him so that he could hook the cable to the bottom of the helicopter. Mike is a great pilot, but that doesn't keep us from being nervous when our precious ice core samples are swinging around underneath the helicopter!

By the time the helicopter took off, the sun was setting, and Bella was finishing up the preparations to start that night's drilling. We really didn't need all five of us to do the drilling–three or maybe four was plenty–but it was a beautiful night and we were just having a good time working, laughing and listening to music.

The drilling went smoothly. Bella lowered the drill into the nearly 20-meter (65-feet)-deep hole and drilled down until she had cut one meter (three feet) of core. Then she broke the core and brought the drill back up with the section of the ice core inside the barrel of the drill. Once the drill was out of the hole, Eric detached the barrel from the drill rig and laid it on its side in the snow. Then Eric gently pushed one end of the ice core section with a long pole until it came out the other end of the barrel to where Doug and I were waiting for it. We were deep enough that the core was solid ice, so it was pretty strong. But we still had to be very careful not to let it slip out of our hands. We laid it carefully on a piece of plastic. Doug measured its length and made note of any unusual layers. I drilled a small hole in the core and placed a thermometer inside it to measure the ice temperature. Meanwhile, Eric and Bella put the drill back together, and she began to lower it down the hole again. Finally, Doug and I packaged up the core in a long, skinny, plastic bag, tagged it with identifying marks and put it in a labeled cardboard tube. Then Jeff put the tube into an insulated core box. The whole process took 10 to 15 minutes, by which time Bella brought up the next core.

If everything is working well, then a rhythm emerges and we can work smoothly for several hours. We have to make sure that everyone stays warm, however, because kneeling in the snow and working with ice can make for cold knees and hands. We often take breaks for a hot drink and some food.

Still not on the nighttime schedule the others were, I had to go to bed around 11 p.m. I awoke at about 2:30 or 3 a.m to some talking and commotion. In a sleepy daze, I fell back to sleep. When I woke in the morning, I found Eric eager to tell me the news of the night. They had indeed reached the bright layer we had seen with the radar: they had brought up a layer of ice that was so warm it was dripping wet—not at all what we expected. This meant a change of plans for the next couple of days. We had to switch to using a drill cutter that could handle wet ice (one that cut by melting the ice rather than with a sharp edge). And we were back to working the day shift. But before we did anything, we wanted to send my video camera down the borehole to see what was really at the bottom of the hole: How wet was it? Was there dirt down there too? Knowing this would help us plan for the next stage of drilling.

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