Well preserved 4000 year old ice – University of Copenhagen

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04 June 2015

Well preserved 4000 year old ice

The camp at around lunch time (midnight) as seen from the north. From left to right: Fuel drums and cargo, generator tent, ice core freezer, drill tent (large white construction), kitchen tent, food storage, medical tent, and sleeping tent. The pole in the front is the weather station.

The camp at around lunch time (midnight) as seen from the north. From left to right: Fuel drums and cargo, generator tent, ice core freezer, drill tent (large white construction), kitchen tent, food storage, medical tent, and sleeping tent. The pole in the front is the weather station.

Today we probably reached a major ~4000 years old volcanic layer in the ice. The ice that will be drilled the coming days is thus of special interest as it covers a time period that is not well preserved in the deep ice cores from the Inland ice (GRIP, GISP2, NGRIP, NEEM).

On the main ice sheet this age interval falls within the brittle zone (approx. 700-1200 m depth), where the ice is not so well preserved (due to high pressure bubbles). In the Renland core, however, we are still above the brittle zone, so the core offers the opportunity to get a well preserved profile of that time period.

The annual layer thickness is currently 2-3 cm, which will allow us to analyze the core in annual resolution. Rather soon, however, annual layers will decrease to mm thickness and we expect to enter the last glacial period (crossing our fingers!)

Drilling progresses at very high speed with 26.4 m production today. Logging depth is 475.12 m.

Weather: It is nice and calm summer conditions. Temperatures -4°C to -14°C, wind below 3 m/s from N. Wind has been from the north since last weekend, so just along the skiway. Perfect camp layout! It is still possible to process ice cores some 12 h per night under sufficiently cold conditions, but temperatures are certainly rising. In the day time the sun warms up the drill tent close to or even above the melting point making core handling impossible.



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