Marine geophysical research
Marine geophysical research is a standard technique to investigate the tectonic, geodynamic and sedimentary history of oceanic ridges, basins and shelf areas. A wide range of methods (seismic reflection, seismic refraction, gravity, magnetic) is applied from the vessel to achieve the goals of the projects. In polar regions mostly standard equipment has been used, which was modified to being operated in the harsh climate conditions. A special challenge is to conduct seismic experiments in ice cover regions. The equipment has to withstand collisions with ice floes or even being dragged across it. In the central Arctic Ocean even a second ice breaker might be necessary to ensure any progress and a reasonable data quality.
Keeping this in mind the marine geophysical investigations are rare in areas with dense and/or difficult ice conditions, and have a reasonable signal quality. Consequently, AWI could only collect a few lines in the Arctic, while the bulk of data is around Svalbard and the East Greenland shelf. In Antarctica the western Weddell Sea is the problematic area. Here, only few cruises could penetrate the pack ice and gather reasonable data.
In Antarctica and the Arctic the projects have more or less the same objectives:
- To reconstruct the paleo positions of the continents, e.g. to solve the gateway problem in the North
- To map the structure and distribution of the sediments with special emphasis on glacial sediments to better understand the consequences of ice sheet dynamics for depositional processes.
- To investigate drift sediments to better describe paleo currents
- To investigate the deeper crustal structure along the margins, which would allow a volcanic or non-volcanic classification and to understand the driving processes for continental break-up.
If necessary geophysical investigations were also carried out around Africa in order to investigate the conjugate margins to better understand geodynamic processes or the history of current systems, which are relevant for the climate evolution of Antarctica.