Description:

Studies at the rifted continental margins of Norway and Greenland give information about theopening of the Arctic gateway. The geologically well studied Norwegian continental margin between the Jan-Mayen fracture zone and the Senja fracture Zone shows similar structural elements to the conjugate East Greenland margin. Until now it has not been possible to compare the general sedimentary structures of the conjugated margins.

Only sparce seismic data exist in the Norwegian Greenland Sea. Seismic data were collected with “RV Polarstern” in the Norwegian Greenland Sea during the expedition ARK XIX/4, in the summer of 2003. In total, 15 profiles with a 600 m streamer, 13 profiles with a 3000 m streamer (4364 km), and four seismic refraction profiles were acquired to map the deep structure of the East Greenland continental margin and its transition to oceanic crust. The profiles are located between 72°N and 77°N (Fig. 1). The new data base allows for the first time an extensive analysis of the sediment structures in the Norwegian Greenland Sea and comparison with the surrounding margins. Only one published seismic reflection profile, from 1986 exists in the Norwegian Greenland Sea. This profile was reshot (AWI-20030390) with an enhanced acquisition set up. Indications of the presence of seaward dipping reflectors, which mark the transition zone of continental to oceanic crust, are found in conjunction with the Greenland Escarpment. At the conjugate Voring Plateau escarpment we can clearly see similar reflectors, which are indications of subaerial volcanic activity. With the help of ODP-Site 913, located on line AWI-2000390, we have the possibility to provide an age model of the sediments and estimate the ages of the glacial sediments on the East Greenland shelf. This dating is very important for an advanced understanding of glacial / interglacial cycles of the East Greenland ice sheets.

Next working steps:

• Data processing
• Investigation of depositional structures and distribution of glacial sedimentation north of 72°N, including information from ODP-Site 913
• Investigation of depositional structures and distribution of glacial sedimentation south of 72°N and in the Barents Sea. It is important to know, there are differences in the development of the whole glacial shelf region of East Greenland
• Stratigraphic interpretation of Cenozoic sediments correlated with ODP boreholes to give a first age model for the Norwegian Greenland Sea
• Analysis of the seismic data in terms of the number and style of advances and retreats of the Greenland / Barents Ice sheets (aggradation, progradation). How often does the ice sheets advanceand is it possible to give a statement about the onset of the glaciation through the age correlation?
• Basin modelling should answer the questions: How and when did the Norwegian Greenland Sea develop? Are there other processes in different basins which can influence the development in general?
• A complete interpretation of all existing and accessible geophysical and geological data from the Norwegian Greenland Sea is interesting for a comparison of the conjugate margins.

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