The Svalbard Eocene-Oligocene (?) Central Basin succession: Sedimentation patterns and controls

A synthesis has been undertaken based on regionally compiled data from the post early Eocene foreland basin succession of Svalbard. The aim has been to generate an updated depositional model and link this to controlling factors. The more than kilometer thick progradational succession includes the offshore shales of the Gilsonryggen Member of the Frysjaodden Formation, the shallow marine sandstones of the Battfjellet Formation and the predominantly heterolithic Aspelintoppen Formation, together recording the progressive eastwards infill of the foredeep flanking the West Spitsbergen fold-and-thrust belt. Here we present a summary of the paleo-environmental depositional systems across the basin, their facies and regional distribution and link these together in an updated depositional model. The basin-margin system prograded with an ascending shelf-edge trajectory in the order of 1 degrees. The basin fill was bipartite, with offset stacked shelf and shelf-edge deltas, slope clinothems and basin floor fans in the western and deepest part and a simpler architecture of stacked shelf-deltas in the shallower eastern part. We suggest a foredeep setting governed by flexural loading, likely influenced by buckling, and potentially developing into a wedge top basin in the mature stage of basin filling. High-subsidence rates probably counteracted eustatic falls with the result that relative sea-level falls were uncommon. Distance to the source terrain was small and sedimentation rates was temporarily high. Time-equivalent deposits can be found outbound of Stappen High in the Vestbakken Volcanic Province and the Sorvestsnaget Basin 300 km further south on the Barents Shelf margin. We cannot see any direct evidence of coupling between these more southerly systems and the studied one; southerly diversion of the sediment-routing, if any, may have taken place beyond the limit of the preserved deposits.

Automated summary

The study synthesized data from the post early Eocene foreland basin succession in Svalbard to generate an updated depositional model, revealing a foredeep setting governed by flexural loading with high sedimentation rates and uncommon relative sea-level falls. The basin fill had a bipartite structure with shelf and shelf-edge deltas, clinothems, and fans, suggesting a wedge top basin in the mature stage. Time-equivalent deposits were found in other regions, indicating potential southerly diversion of sediment-routing.