Formation and reorientation of structure in the surge-type glacier Kongsvegen, Svalbard

Kongsvegen, a surge-type glacier in Spitsbergen, Svalbard, shares a tide-water margin with the glacier Kronebreen. The complex has been in retreat since a surge advance of Kongsvegen around 1948. The surface of Kongsvegen displays suites of deformational structures highlighted by debris-rich folia. These structures are melting out to form a network of sediment ridge in the grounded terminal area. The structures are also visible in a marginal, 1 km long, 5-20 m high cliff-face at the terminus. Current models for the evolution of deformational structures at Kongsvegen divide the structures into suites based on their orientation and dip, before assigning a mechanism for genesis based on structure geometry. Interpretation of aerial photographs and field mapping of surface structures suggest that many structures were reorientated or advected during the surge. We suggest that many of the deformational structures highlighted by debris-rich folia represent reorientated, sediment-filled crevasses. Some evidence of thrusting is apparent but the process is not as ubiquitous as previously suggested. Many deformational structures also appear to have been offset by more recent structures. Mechanisms of structural development must, therefore, be considered within the context of distinct stages of glacier flow dynamics and multiple surge episodes. Furthermore, evidence for thrusting and folding within the glacier systems of Svalbard has been used as the basis for interpreting Quaternary glacial landforms in the UK. The findings of this paper, therefore, have implications for interpretations of the Quaternary record.