June 15, 2023

Possibly the end of EGRIP well-preserved stratigraphy?

The BBQ season has started. Emil fired up the grill for the first time this season. It was too windy to eat outside, but the summer spirit was definitely there.

Drilling had a slow start today with a short circuit in the drill connecting cables. It was repaired and the drill went downhole in the afternoon. First run of the day resulted in a 1.5 m core whereas the second run provided 3.35 m of core. Quite amazing that it is still possible to drill such long cores at this depth and that close to the melting point of the ice. The third run gave some 2 m of ice core. In contrast to the previous runs, however, the core did not break easily. Pulling at 2200 kg, the ice decided to tease us for some minutes before finally releasing the core: If you really want this core you need to make an effort.
So far, it has been possible to match up the EGRIP DEP and NGRIP ECM records reasonably well. The match suggests that the EGRIP stratigraphy is continuous back to some 120,000 years. The most recently drilled ice can, however, not be matched up to existing Greenland ice cores in a reasonable manner. The DEP measurements obtained over the last days show abrupt shifts between what appeared to be an Eemian level and what looks similar to a glacial level (see attached figure). Those abrupt changes are hard to reconcile with an Eemian climate that is thought to be stable like the Holocene. Therefore, an immediate interpretation of the EGRIP DEP record is that the ice analysed over the last days is folded or otherwise disturbed. Now, the deepest Greenland ice has previously given us surprises and no firm conclusions can be drawn until we have more records measured and in particular the water isotope record.

What we did today:

1. Drilled three ice cores of 1.5m, 3.35m and 2m length.
2. Logging depth: 2633.70 m. Processing depth: 2629.00 m.
3. Physical properties measurement 2618.55 m.
4. Groomed skiway and checked skiway flags.
5. Repaired connector on drill that made a short circuit.
6. Brought the grill out and enjoyed the first BBQ of the seas.

Weather today: Today was the warmest day we have had so far this season. A good occasion to fire up the grill. Temperatures -12°C to -4°C. Wind 2-16 kt from E – SW – SE – and finally S.

FL, Anders Svensson

We now have a few flowers up on the ice sheet – maybe the only ones? It is tough for flowers to survive on the ice sheet (as we tend to forget watering them).

The breakdown of the EGRIP DEP – NGRIP ECM matching at around 120,000 years. Abrupt shifts in the EGRIP DEP record are unexpected in an Eemian setting and may suggest disturbed or folded ice.