6 July 2011

A basal ice core with stones

tekst
4 inch 37 cm basal ice core.

Today the HT drill was used with the new and innovative carbide step cutter and they drilled through ice, sediments and rocks! Great success!

(HT drill - read the Reacher page at the CIC homepage. Opens in new window)

We observed that the liquid near the base is conductive and the drill frequently shorts near the bottom. Scott detects high concentration of iron in the basal sediments. Do these impurities make the basal liquid conductive?

The ‘rotten’ ice found above the regular ice drilled now could also indicated seeping water. Do the impurities change the freezing/melting point of the basal water?

The drill liquid near the base is being tested and Steff has improved the insulation of the electrical gliders on the skate section of the HT drill.

What we have done today:
1. Bailing of drill liquid out of the 2011 S1 borehole
2. Drilling in the NEEM deep borehole with a 1 inch rock drill
3. CFA team packing
4. PICARRO measuring at the water vapor station
5. Temperature measurements at the 2009 S1 shallow borehole site completed.
6. Grooming skiway
7. Removing snow around the sauna garage and equipment from the garage tent
8. Ordering food for 14 July mission

Ad 2: The ICDS rock drill was tested twice in combination with the Bern pump and the CPH. super banger. It brought up two "cores" consisting of unusual ice pieces. The ice pieces appears more like "rotten ice" or refrozen water drops, than chips or broken off pieces from our drilling activity. We cannot at this time account for these "chips"

The new carbide step cutters has now been installed onto our standard drill head on the HT drill, and they proved very efficient in penetrating through silty ice containing small stones. We drilled smoothly into the bottom ice and retrieved 31 cm of core with several bands of silt and 20 cm of the unusual ice pieces on the top. The current was low and the pitch was constant even when cutting through the small stones.

The reason for the short core was not due to penetrating problems or high current, but due to the fact that the lower 5 -10m of our drill liquid has become conductive, causing shorts in the anti torque section. We have improved the insulation around the slide contact this afternoon and will continue the drilling tomorrow morning.
Drillers: Jacob, Jay and Steff

Weather: Blue sky, temp. -16°C to -6°C, wind 4-16 knots from SE.

FL, Dorthe Dahl-Jensen


Top end of the basal ice core. The sediment layer that stopped us last year?


Scott’s geology lesson on the rocks found among the ice cuttings. 

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