Signs of deformation – University of Copenhagen

19 July 2018

 Thursday 19th of July 2018

Left: Christine looking through a glacial section of the EGRIP core, showing that it is nearly completely transparent. Right: but in the line scanner it is easy to see that the cores in fact contain many cloudy bands, and that they are not completely straight.

Signs of deformation

The EGRIP camp is situated on the North East Greenland Ice Stream (NEGIS) and is thus moving almost 60 m with the flow every year. Normally this is not something we can see unless we do GPS measurements, but during the last few days it is clear from the ice core we drill that we indeed are in a dynamic place. The sign of this flow can be seen as unusual deformation of dust layers in the ice. Normally these layers are thin straight horizontal layers across the ice core at this depth, but here at EGRIP they are more disturbed with wiggles and uneven thickness (see today’s picture for an example). Exciting to see these layers in the red light of the line scanner.
The drillers are still in their good mode of producing nice 3.5 m long ice cores almost every run, so today they managed to increase production beyond 20 m, and recover 57 kg of chips during the filtering night shift. Furthermore the drilling passed the 1500 m mark, so a small celebration was in order. The crews in the processing line, the CFA isotope lab. and in the Physical Properties lab. all continued making good progress during the day.
Towards the end of the day, Chris picked up equipment at RADIX with a Pistenbully and drove it toward EGRIP.

What we did today

  1. Drilling of 24.4 m of ice core and retrieving 57 kg of slush through filtering.
  2. Logging of main core, depth at 19.00 today: 1515.07 m.
  3. Processing in the science trench down to 1444.3 m.
  4. Measurements in isotope laboratory to 1278.75 m.
  5. Measurements in physical properties laboratory to 1444.3 m and volume sample.
  6. Water vapour sampling and measuring.
  7. Packing down at the RADIX site, and return of equipment to EGRIP.
  8. Preparing Japanese surface program cargo for tomorrows Skier.

Weather: Cloudy start to the day, but turning sunny around lunch, and staying mostly clear the rest of the day. Temperature -25 °C to -12 °C and wind from NW turning W during the day, up to 9 kt.

FL, Bo Vinther

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