5000 Metres Beneath the Sea
 

Mineralogist from the University of Hannover Does Research into the East Pacific Ridge

The Institute of Mineralogy of the University of Hannover is the only research Institute in the world to be able to realistically reconstruct in an experiment the processes in the magma chambers in the earth's crust beneath the ocean, which is up to 7 kilometres thick. “Our test facility is designed in such a way that we can even check volatile components such as water and oxygen at temperatures of between 1000 and 1250 degrees and at pressures corresponding to those up to 20 km deep in the earth (8000 times above normal pressure). In this way we can simulate the magmatic development in the magma chambers”, says Koepke. This is why he was one of the two German researchers on this international expedition. The American drilling ship “Joides Resolution” left Acapulco on November 12, 2005 for the subterranean volcanic range, the East Pacific Ridge, 750 kilometres off the coast. “This location is particularly suitable for our drilling because it is geologically active and the earth’s plates drift apart extraordinarily quickly here - 20 centimetres per year”, Koepke explains the choice of the location. The scientists remained on the drilling ship for six weeks, and Koepke has been back in Hannover since the beginning of January.

Participation in the international “Integrated Ocean Drilling Program” (IODP) is funded by the German Research Society. It gives the participating scientists complete access to the samples and the guarantee that the research results will remain within the research group for three years - the best conditions for top-class research.

The drilling operation within the “Sheeted Dikes”- basil eruptions lying in thin layers - proved to be particularly difficult. The number of useful samples obtained was extremely small here. However, after five weeks of drilling, and accompanied by the cheers of all involved, those rocks were brought to the surface which typically develop when the magma chambers beneath the oceanic volcanic ridges cool off - the “oceanic” gabbros. A great success for the team of researchers. Since the sea bed is so difficult to reach only models have been available until now, and they were deduced either from seismic investigations or from fossilised sea beds, and their correctness was discussed controversially. The unique cross-section through the ocean’s crust together with the samples obtained will from now on be the reference profile for the structure of the oceanic crust.

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