On the origin of large shelf embayments on glaciated margins—effects of lateral ice flux variations and glacio-dynamics west of Svalbard

• Published in: Quaternary Science Reviews
• Main Authors: Vanneste, M., Berndt, Christian, Laberg, J. S., Mienert, J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2007
• Subjects: Svalbard
• Online Access: https://oceanrep.geomar.de/id/eprint/19169/; https://oceanrep.geomar.de/id/eprint/19169/1/Vanneste_2007_scan.pdf; https://doi.org/10.1016/j.quascirev.2007.05.005

Glaciated continental shelves are characterised by large amphitheatre-like embayments between prominent cross-shelftroughs. The integration of swath bathymetry and high-resolution seismic data (3D, 2D) collected across the western Svalbard continental margin indicates how such embayments form. Although their bathymetric expression resembles headwall scarps of submarine slopefailures, the shelfembayments are the result of the interplay between sediment dynamics and transport underneath fast-moving ice streams in the cross-shelftroughs and the slower-moving parts of the ice sheets on the adjacent shallower shelf banks during full glacial conditions. This is supported by (1) the absence of major landslide deposits at their toe, (2) continuous prograding shelf deposition and (3) absence of landslide-related faulting. Instead, the seismic data suggest a depositional origin of the shelfembayments that is characterised by continuous sediment input at lower rates off a slow-moving ice mass in the centre of the embayment which is fringed by the lateral ice-stream ridges. These findings put into perspective the importance of submarine slopefailure on glaciated margins.