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21 July, 2001
Well, things are getting better. The weather has improved; there is no
rain, and no wind. Not much sun yet either, but fieldwork conditions are
great. Further, Rickard (a graduate student from Stockholm
University)figured out the problem with the drill. So we drilled five
holes at our new location today. I recorded four of these holes on
videotape. Two of the holes went all the way to the bed of the glacier
(120 meters or about 370 feet). This means that we did not encounter any
englacial drainage features during drilling of these holes. Two of the
holes drained at relatively shallow drilling depths - 10 meters and 17
meters.
The cage that I attach to the camera has a number of purposes. First, we
attach a screen to the cage to provide a grid with fixed dimensions. When
parcticles flow by into or out of the conduit we can use this grid to
measure the velocity of the parcticles and hence the flow rate of the water
in the conduit. We also attach thread to look at its deflection in the
flow of water in the conduit. We also attach flexible plastic strips that
will retract into the conduit, from which we can measure the diameter of
the conduit. The cage is made out of copper because this material is
non-magnetic. So, when we attach a compass to get the orientation of the
conduit it will give us magnetic north. Most other common metallic
materials are magnetic and affect compass needles. But, the conduits we
are seeing are not the tube-shaped features that have been theorized in the
scientific literature on this topic. What we are seeing are more
fracture-like. We also do not observe much flow in the conduits unless it
is raining quite hard. We are having quite the discussions about the
nature of these features.
Great working conditions. TEA Robert Schlichting and St. Olaf College undergraduate student Peter Pearson manage the video cable.
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