FS „POLARSTERN“ ARK-XXV/3
Reykjavik – Bremerhaven
Weekly report No. 3, 16.08. to 22.08.2010

Due to the unexpected situation that our survey area was limited to the Greenland part of Baffin Bay, we modified our original survey plan and started our survey operations in reverse order. Therefore, we headed towards the northeastern part of Baffin Bay. The Greenland continental shelf extends up to 200 km from shore and is in general much wider than the Canadian shelf at the western side of Baffin Bay. The continental slope is steeper with several graben structures along the Greenland margin formed during different rift phases in Baffin Bay. In some of these basins, sediment thickness is more than 10 km. Age and formation of the horst and graben structures are not well understood. Our structural and geochemical investigations aim to improve the knowledge about the plate-tectonic processes during the opening of Baffin Bay in Palaeozoic-Eocene times, which formed the Greenland continental margin in Earth history.

After arrival in Greenland territorial waters on August 11th, we had started continuous operations along survey lines on the way north using our geophysical outboard systems.  With the first refraction seismic line, running from the deep central part of Baffin Bay towards the Greenland coast at Melville Bay, we aim to study the deep crustal structures in the central and northeastern part of Baffin Bay. Shortly before starting data acquisition we were contacted by an exploration vessel operating in the area to coordinate further activities. Since the Norwegian seismic exploration vessel RV Bergen Surveyor had a crew change and interrupted its activities for a few days we were able to acquire all data in the Melville Bay as per schedule and in good quality.

The station work to deploy ocean bottom seismometers along the 180 nm long line was combined with heat flow measurements and sediment coring using a gravity corer. After minor problems in getting sufficient amounts of sampling material we extracted sediment cores of more than 3 m length. The samples are now under processing and will be analysed by our geologist and geomicrobiologists. At the end of our survey line we were excited by the impressive coastal landscape of Melville Bay with high rock escarpments and surrounding glaciers draining the Greenland icecap. In prolongation of our refraction seismic line we deployed a landseismic station. This gave opportunity to have some colleagues to go ashore by helicopter.
Later on, we continued geophysical data acquisition along survey lines heading towards Upernavik, a small community at the Greenland coast 230 nm away to drop off our three Canadian and two German colleagues, who had to depart from the little airport there to return home. Since the decision of the regional Nunavut Court of Justice stopped all NRCan activities within its ECASE project the Canadian project partner also decided to halt activities within our BGR project.  
The departure of our Canadian colleagues also results in additional work for our onboard scientific crew since our guest scientists have been fully integrated into shift schedules on all onboard activities. But we were also very sorry not to continue this fruitful cooperation with these highly experienced and friendly colleagues.
The scientific discussions to elaborate a modified working programme to adjust our expedition to the new conditions are almost completed. All colleagues are highly motivated even under the changed circumstances and send greetings home.

Volkmar Damm                                     August 21st,  2010,  Baffin Bay,  5°C