Reykjavik – Bremerhaven, 30 August - 5 September 2010
 
As per schedule, we arrived Monday evening at the northern end of our north heading profile. After completing this line with reflection seismics, magnetics and gravity methods, we headed south again deploying 28 ocean bottom seismometers at equidistant positions. At preselected locations, heat flow measurements were conducted. This profile extends from old Proterozoic crust in the North to the suspected extinct spreading axis in the central part of Baffin Bay. It crosses thick sediment layers deposited on top of the Palaeozoic basement. Based on our seismic and potential field data we aim to better define the transition zone between continental crust in the North and oceanic crust in the South. Refraction seismic investigations is the main tool to get information on the deeper crust, whereas our high resolution reflection seismic data will be used to analyze the internal structure of sedimentary basins for subsequent modelling of basin evolution. Weather conditions were perfect while sailing north acquiring geophysical data along the line, which terminated a few miles off Northumberland Island. Part of the track was in the near-coastal waters along Steensby Land in the Northwest of Greenland. Apart from the US military Thule airbase the only Inuit community in this fiord land area.is Qaanaaq in Murchison Sound. This village is the northernmost Greenland community. Most villagers were moved here from their former settlement Thule in 1953 after the military airbase was founded during the Cold War.

Good weather conditions and the short distance to the coast made it possible to further continue our geological sampling programme using the helicopter.

We were happy to get on Tuesday the expected research permission from the Danish Ministry of Foreign Affairs to conduct our extended research programme in Greenland waters. Half of our research cruise is now over and we must not waste time to complete all additionally planned work.

On Friday after two days of recording refraction seismic data the 400 km long N-S line was completed. Only one break interrupted the seismic signal generation the night before. A rope for towing our airgun array had damaged the high pressure air umbilicals of our airguns. Our technicians fixed the problem within 2 hours and then we continued to work along the profile.

Since noon on Friday we have been retrieving OBS instruments. There is always an air of excitement when waiting for the released OBS coming up to the sea surface and monitor if they appear at the expected position.  A special situation happened when we discovered that a large iceberg covered the expected position where an OBS was planned to be retrieved. But after careful calculations we were sure that there will remain a small distance between the iceberg and the OBS when we released the OBS anchor. All calculations were perfect and we finally retrieved the instrument 50 m in front of the iceberg.

All colleagues send greetings home from our today’s Mid Cruise Party.

Volkmar Damm
September 4th, 2010, Baffin Bay, 2°C