29 September - 5 October 2008 (Reykjavik – Bremerhaven)

Middle of this week, we crossed the Lomonosov Ridge. This structure stretches from Siberia to North Greenland across the entire Arctic Ocean. It rises up to 2500 m above the surrounding abyssal plains. A deep drill hole in 2004 close to the geographic North Pole confirmed that this ridge consists of continental crust. This mountain chain was attached to the continental shelves of Svalbard and Siberia approximately 55 Myr ago. The continental drift with a spreading velocity of 10 mm/yr separated the Lomonosov Ridge from the shelves, and shifted it to its current position, and is still active. However, this time we passed the ridge just in transit to our next oceanographic station. There was no time for any other research activity.

On Wednesday, the station work across the ridge had been finished, and the ship headed towards the Gakkel Ridge to continue our programme. However, the transit was more difficult than expected. The ice floes were larger than in the east, and wind/currents have almost closed the leads between the floes. As a consequence, the ship got stuck several times, and all four engines were needed to proceed. At 10 pm, the geophysists were very optimistic that they could acquire another long seismic profile across the Amundsen Basin. At midnight, their programme had to be terminated. The ship was stuck in the ice again. To save time for the last stations on the Gakkel Ridge, we steamed without any further geophysical profiling towards our last ice station.

On Friday morning we arrived at an ice floe just above the ridge. The day was full of activities. While the oceanographers, supported by people from all groups, installed their last buoy array, other scientists took the last opportunity to walk on an ice floe. After a final group photo we left the floe for dredging a submarine volcano. The volcano had an altitude of 2500 m, and its peak was located at 2300 m below the surface. The entire station work took us six hours. After some difficulties, almost 500 kg of volcanic rocks had been accumulated on the working deck. This was an excellent result, and a clear hint that the structure underneath the ice is tectonically active.

At midnight, we steamed south. We were on our way home and took the fastest way out of the pack ice. The clear sky with temperatures of -14°C allowed us to observe our first northern lights during this cruise, a spectacular view. During the next days, we continued our transit towards the Vilkitsky Strait in the south. To do this, the ship did not sail a strait line, but used the leads (10-50 m open water ponds) between the large ice floes. We had to break ice floes directly only a few times. Though we were sailing a zick-zack course, it was the best method for sailing through the ice with a minimum of fuel consumption. Today, Sunday afternoon, we passed the ice edge and terminated our research programme.

Everybody is healthy and sends their greetings to the people at home.

Wilfried Jokat
October 5, 2008
78°00`N 115°00’E, -9.0°C