Twentieth “Polarstern” expedition to Arctic is drawing to a close

On October 3rd, the German research vessel “Polarstern” of the Alfred Wegener Institute for Polar and Marine Research will return to Bremerhaven from its 20th arctic expedition. During the last leg of the voyage, 44 scientists from Germany, Russia and South Korea, supported by crew members, helicopter pilots and technical staff, investigated the region north and west of Spitsbergen. Emphasis was placed on geophysical and geological studies of Fram Strait and Yermak Plateau. Of primary importance were seismic surveys of the upper kilometres of the ocean floor, and the sampling of sediments by means of various sounding devices.

The large sliding masses on the northern continental edge of Spitsbergen were among those investigated within the framework of the geology programme. Sliding masses are the result of major sediment shifts, which occur as a consequence of sudden events, such as earth quakes or instabilities on the upper continental slope following massive increases in sediment influx. The investigations are part of the international research project “Euromargins”. Of particular interest in this context are dating such events, estimating the magnitude of shifted sediments and interpreting the data sets with regard to climate changes during the past 150,000 years.

Fram Strait is the only deep water connection between the Arctic and the world’s oceans. In its centre, an active, slowly widening mid oceanic ridge is, even today, the reason why Spitsbergen is moving away from Greenland. According to current knowledge, the influx of cold arctic water through Fram Strait has been of major significance for the frequent cycles between warm periods and ice ages over the last millions of years. However, details about the temporal sequence of tectonic plate movement, important information for exact climate reconstructions, remain highly speculative.

“In particular, the new seismic data sets will enable scientist to improve the planning and implementation of scientific deep drilling expeditions to Fram Strait, Yermak Plateau and the region near East Greenland within the international drilling programme IOPD (Integrated Ocean Drilling Program)”, says expedition leader Prof Dr Rüdiger Stein of the Alfred Wegener Institute. “These drillings in the Arctic represent a major challenge for marine geosciences. They will contribute to solving the great mystery of changes in Arctic plate tectonics and paleaoclimate during the course of the past 120 Million years”, explains Stein.

A reconnaissance trip dedicated to the lost German arctic expedition of 1912 has been added to the expedition programme. Scientists of the Max-Planck-Institute in Seewiesen identified and recorded the expedition’s landing site in Duvefjord (Nordaustland, Spitsbergen at 80.17 N, 24.10 E) as well as the landing site of a secondary expedition in 1913 in Beverlysund, near North Cape, where the expedition vessel “Loevens-Kioeld” froze in pack ice and sank in 1912. The location of the sinking has been narrowed down with the help of historical stereo images and field surveys. The ship is the most northerly positioned wreck in the world, and is scheduled to be studied in detail using the dive vessel “Jago” in 2006.

“Polarstern” will undergo some maintenance work in the dockyard in Bremerhaven, during which time it will be prepared for its 22nd expedition to Antarctica beginning October 12th.