Fieldwork in Greenland, the construction of an ice drilling camp at 77°N

This summer (2008) I spent 39 days on the Greenland ice sheet, the last part of the second NEEM field season. The aim of this project is to drill a deep ice core, that will yield ice (and air) from the last interglacial period, the Eemian (130,000-115,000 ybp).

In 2007 the NEEM project started at the old drilling site NGRIP. Drilling equipment was transported from there to NEEM (370 km) and on the way two shallow ice cores were drilled and a radar survey was done. At the NEEM location (77°55’N, 51°03’W, 2483 m a.s.l.) another core was drilled and preparations for the next field season were done.

This year, the first people were put in NEEM on May 7th. They started the construction of the camp and they prepared the skiway so that the Hercules planes with heavy cargo could land safely. By the end of May the camp consisted of two red domes, a large garage and six weatherports. In June the construction of the Main Dome and the digging of the drill trench and science trench started.

On June 30th the drilling of the NEEM ice core started in the drill trench. For the first 100 m the 3" Hans Tausen drill was used with no drilling fluid. On July 3rd a depth of 106.16 m below the 5 May 2008 snow surface was reached. Then the drill was used to ream the hole to a larger diameter to fit the casing for the liquid drilling. From 104 mm to 135 mm (7 July), 185 mm (8 July), 222 mm (10 July), 255 mm (13 July) to the final diameter of 281 mm on July 16th.

In the meantime, the Dome was just ready for use on the 11th of July, the day that I arrived with twelve others, making the total of 32 persons in camp. But for more than a week there was still no running water, and the kitchen was not yet installed. All water for drinking, cooking and cleaning had to be prepared by collecting snow and melting it in a 75L barrel. Filling the snowmelter is a never-ending job.

According to the field plan, my job was the processing of the ice core, together with Valérie Masson-Delmotte en Bo Vinther. The processing consists of measuring and logging of the core and comparing this to the drillers’ notes, cutting the cores in lengths of 165 cm; sawing a strip of the ice core, dividing this strip in 2.5 cm pieces for stable isotope measurements, and performing electrical conductivity measurements on the flat cut surface of the remaining core. Cores that were to be shipped were then cut in 55 cm pieces to fit the ice core boxes. Bo had prepared 25,000 plastic bags for the isotope samples that were expected this year.



Apart from the main core, several shallow cores were drilled at a site 1500 m from camp. Here, an American and a European firn gas team each drilled a hole that was used for collecting air samples from the firn. They started drilling on July 15th, using the hand drill. After drilling a few meters, a rubber bladder is inflated in the hole, and from underneath the bladder air is pumped out of the firn. We processed the snow and firn from the upper 5 m for isotopes only (since the snow core is too fragile to move or keep) and the rest of the cores as above.