Neptun’s visit

RV 'POLARSTERN' ARK XXIV/3
Reykjavik – Bremerhaven
14 September to 20 September 2009

The last week in our research area was quite eventful. On Monday, we had to interrupt a seismic profile because of bad weather conditions. Therefore, the scientific program had to be changed, and the ship moved into the Kong Oscar Fjord again. After the wind calmed down, we started to acquire a long seismic reflection profile from the inner fjord to the mid-ocean Kolbeinsey Ridge. Much to our surprise, the landscape of the fjord coast had changed completely since our last visit. The low-pressure system from Monday caused a massive snow fall. The landscape looked quite winterly.

Neptun and his loyalty felt invited by our presence in the fjord to visit the ship and to perform the traditional north polar baptism. In the evening, his visit was celebrated with a traditional barbeque party.

Back to science! We had to interrupt the seismic profiling again because of technical problems within the streamer cable. The cable could not be repaired on the vessel. We continued with heatflow measurements, which provided us with some information on the thermal status of the upper mantle. The first measurements already showed that the heatflow in our research area was much higher than the global average. The new data will hopefully allow for some interesting interpretations after having been analyzed in detail.

The final results of this expedition are mainly positive. While the geologists, geodesists, biologists, chemists and physicists have mostly achieved the objectives of their projects, this is not the case for the geophysical program. In addition to some technical problems, the ice conditions off East Greenland were poor to the point that the original scientific goals to gather seismic data across the northern East Greenland shelf/margin could not be accomplished. Though the ice floes north of 75°N latitude were quite loosely distributed, most of the planned research area was covered by more than 50% pack ice, too dense to safely tow our 3000 m long sensor cable. Therefore, this part of the geophysical program was completely cancelled. The other experiments, heatflow and deep seismic sounding to probe the crustal thickness, were very successful since their layout and locations could be adapted to the ice conditions. The simple truth is that the geophysists chose the wrong “ice year” off East Greenland to conduct measurements across the margin. However, such conditions cannot be predicted, and are part of taking the risk in conducting research in ice-covered areas.

The scientific programs will terminate at the beginning of next week. The journey back to Bremerhaven will be used to disassemble scientific equipment, clean the labs and stow the expedition goods back into the containers. Furthermore, all preparations to optimize the unloading of the cargo in Bremerhaven as well as the stay in the shipyard have started.

The ship will arrive in Bremerhaven on Friday, September 25th at 07:00.

Best wishes to the readers at home

Wilfried Jokat
20 September 2009, North of Iceland
+1°C          72°11’N  014°40’W