NEEM production curves – University of Copenhagen

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03 July 2009

NEEM production curves

The daily progress in drilling, ice core processing, and CFA analysis.

The daily progress in drilling, ice core processing, and CFA analysis. The x-axis shows the NEEM field season 2009 and the y-axis shows the depths in meters.

Each day, we note the drilling depth, the ice core processing depth, and the depth of the CFA analysis (see figure). The drilling is now in the brittle-zone that covers roughly the interval 600-1200 m depth. The ice in this interval is not suited for processing this year because of high pressure air bubbles and we, therefore, store the brittle ice in a core buffer until next year, when it has relaxed. The plan is that drilling goes on as fast as possible throughout the brittle zone, whereas the ice core processing and the CFA analysis stop at the onset of the brittle zone and only continues when drilling reaches ice below the brittle zone. From the curves in the figure one can speculate about how far the project will reach this year. There are still 4-5 weeks left of the season where drilling can continue, so if everything continues to run smoothly, drilling could actually reach rather far already this year. We knock on wood and hope that drilling can reach bedrock at 2565 m depth in 2010.

What we have done today:

  1. Drilling with the NEEM long drill: 30.99 m. Drillers depth: 860.55 m.
  2. Restarted logging at 561.55 m depth. Final depth: 568.15 m.
  3. Ice core processing: 23.10 m. Depth: 550.55 m.
  4. CFA analysis: 22.55 m. Depth: 231.00 m.
  5. Preparing rain gutters for protecting brittle ice in the core buffer.
  6. Starting to collect shallow drill parts.
  7. Building ice bar for tomorrow night.

Ad. 1: Drillers Report July 2: "In the drilling trench too we celebrated passing 800 m, recovered 33.5 metres of core and finished the day at 829.56 m."

Ad. 2: The cores we are now logging have been stored for more than ten days in the core buffer to relax. We bring the cores back to the logging table in the drill trench and log and cut them into 1.65 m long sections. The logging and the sawing does not introduce new cracks in the cores. Tomorrow we will test if we can also process the newly logged cores without making new cracks. If so, we may continue the ice core processing for a few more days and thus increase the onset-depth of the brittle zone. This would make a little room in the ice core buffer for processing below brittle zone. The ice core buffer is now about -18°C and both the science trench and the logging table are about -15°C. The temperature difference does not seem to affect the cores.

Weather: Just like yesterday we had some wind and slight snowdrift during the day, but clear blue sky and beautiful weather during the night. Temperatures from -12°C to -20°C. It appears that the storm is waiting for next week.

Field leader Anders Svensson

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