Basement structure of the north‐western Yermak Plateau

The separation of Northeast Greenland and Svalbard was achieved by large strike slip movements in Cenozoic times. Evidence for these movements can be found onshore both on North Greenland and Svalbard. However, the role of the Yermak Plateau in this process is quite speculative. New multichannel seismic (10 km spacing) and aeromagnetic data (7.5 km spacing) across the north‐western part of the plateau show that the acoustic basement has a similar strike direction to that of the geological units onshore Svalbard. A prominent fault zone separates these most likely continental structures in the west from a more N‐S extended transitional crustal block in the eastern part of the plateau. This part of the plateau is characterized by strong magnetic anomalies at least indicating highly intruded and stretched continental or even oceanic crust. However, the seismic data show that the plateau‐like bathymetry is quite young. During most of its Cenozoic history the Yermak Plateau had a rough topography, similar to the topography onshore Svalbard. Thus, the paleo‐bathymetry might have played an important role for the water exchange between the Arctic Ocean and the North Atlantic prior to the opening of the Fram Strait, which is today the main pathway for the deep‐water masses.