4 July 2010

What kind of ice are we drilling?

Summer in the middle of the greenlandic ice sheet
Outdoor table tennis. It must be summer time.

Everyone involved with the NEEM project is of course extremely excited to know what kind of ice that is being drilled these days. At this point it is very like that we have ice from the Eemian period. This is based on high oxygen isotope values, large ice crystals and high ECM values. At the same time it is certain that the NEEM record looks quite different from the NGRIP record, which is thought to be undisturbed all the way to bedrock. This we can see from synchronization and comparison of the various records from the two cores.

Right now, we simply don't know the reason for the dissimilarities of the two ice core records. It may be that they are ‘true' differences caused by the different drill site locations, local changes in the height of the ice sheet during the Eemian, changes in the position of ice divides, changes in past accumulation patterns etc. There is of course also the possibility that the layering is somehow disturbed in this deep part of the NEEM core like it was the case for the GRIP and GRIP2 ice cores. At this point, we can say nothing for certain.

Drilling: 7.24 m, drillers depth: 2349.60 m.
Logging: 7.27 m, loggers depth: 2365.95 m.
Processing: bag 4218-4249 (17.60 m) 2336.95 m.
CFA: bag 3546-3549 (2.20 m) 1951.95 m.

What we have done today:
1. Drilling and core logging ice.
2. Processed deep ice cores.
3. CFA measurements.
4. Making inventory of drill liquid and ice core boxes.

Weather: Still summer time up here. Clear blue sky, low winds from SE and temperatures -16 °C to -5 °C.

FL's Dorthe Dahl-Jensen and Anders Svensson


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