Linking the Tectonic Evolution of the Northeast Atlantic and the Arctic: Paleobathymetry Reconstructions and Paleoceanographic Implications

The Late Paleocene epoch marked a substantial change in the tectonic regime of the North Atlantic and the Arctic: after a rapid continental break-up new oceanic crust formed in several basins along the Eurasian, Greenland and North American margins. In the Northeast Atlantic small oceanic basins developed between large land masses, microcontinents and transform faults (like the Norwegian and Greenland basins which were isolated from the Eurasia basin to the north and the Irminger and Iceland basins to the south) that hindered the formation of deep oceanic currents. The most significant change in the tectonic configuration of this region that profoundly modified the oceanic paleocurrent patterns and subsequently the global climate was the (middle) Miocene opening of the Fram Strait.

Here we present a series of paleobathymetric reconstructions of the North Atlantic and the Arctic using a detailed and updated kinematic model and published sediment thickness information. The kinematic model was constructed based on available geophysical data (mainly magnetic and gravity anomalies) and was combined with thermal subsidence models for calculating the paleodepth of various basins and ridges through time. Our models suggest that the Fram Strait evolved from a narrow strait in early Mid Miocene (ca. 50 km wide and more than 2000 m deep) to a wider and deeper gateway after 10 Ma (about 100 km wide and more than 3500 m deep). The proximity of continental margins and the presence of shallow continental blocks and volcanic plateaus complicated the architecture of this oceanic gateway. The implications of these changes for the formation of deep-water circulation between the North Atlantic and the Arctic regions are discussed and possible paleooceanographic scenarios are proposed.