June 1, 2018

Ice cores and snow caves

Jens Jakob (right on left picture) and Ståle after opening of the new balloon cave. The deflated balloon is still lying on the floor in the cave.

Tonight, the drillers’ depth gauge shows more than 990 m. As the borehole is more than 10 m below surface, we have in fact crossed the 1 km mark of ice core drilling at EGRIP. In the science trench, the processers have really gained speed, and they are removing ice cores from the buffer at a higher rate than the drillers fill it up. Based on the statistics of this week, it also means that the drillers may reach the end of the brittle zone at 1250 m almost at the same time as processers finish the 2017 brittle core and then processing may continue of the 2018 non-brittle ice directly. We are so far very satisfied with the quality of the EGRIP brittle core, and it appears that all our efforts of protecting the brittle core have paid dividend. Another small land mark was passed as Jens Jakob and Ståle gained access to the new balloon cave. And it looks nice. Later this month, this cave will be used as a concert hall for ice music; but for tomorrow, we plan for a more mundane use, and we will share a Saturday evening drink in the new facilities. 

What we did today:

1. Ice core drilling in two shifts. Status at 20.00: 20.50 m drilled in 8 runs. Drillers’ depth: 991 m.
2. Grooming skiway.
3. Excavated tunnel and gained access to new balloon cave.
4. All Nansen sleds repaired.
5. Ice core processing 36.30 m, bags 998 – 1063 (548.35 m – 584.65 m).
6. Measurements in isotope laboratory.
7. Measurements in physical properties laboratory. At bag 856.
8. Water vapour sampling and measuring.
9. Surface snow sampling.

Weather today: Last night: Strong wind with snow drift. Today: Varying between overcast and blue sky. Temp. -11 ºC to -19 ºC. Wind: 10 kt to 24 kt from W then SW. Visibility: Unrestricted.

FL, J.P. Steffensen

Brittle ice cores in the logger cabin more than one hour after drilling. Top (rear) core is an example of a core with most internal cracks. The bottom (front) core is a 2 m section without any cracks at all. Both core are from around 980 m depth.