Glacitectonic composite ridge systems and surge-type glaciers: an updated correlation based on Svalbard, Norway

Abstract

Glacitectonic composite ridge systems are found at the margins of a number of surge-type glaciers globally. On the High-Arctic archipelago of Svalbard, the pioneering work of Croot (Glaciotectonics: forms and processes. Balkema, Amsterdam, 1988) highlighted the coincidence between composite ridge systems and surge-type glaciers on the island of Spitsbergen. These observations have contributed significantly to our understanding of the links between glacier surges and the landforms they produce. We update this work and expand it to the whole archipelago using the Norwegian Polar Institute’s TopoSvalbard aerial photograph archive to identify 50 composite ridge systems. These are found on all four of the largest islands: Spitsbergen, Nordaustlandet, Edgeoya and Barentsoya, and at the margins of both tidewater and land-terminating glaciers. Of the 50 composite ridge systems, 49 are associated with glaciers that have either been documented as surge-type or contain indicative geomorphological evidence of surging in the form of crevasse-squeeze ridge (CSR) networks. This provides further support for the established link between composite ridge systems and surging. Based on the proportion of glaciers that are documented as being of surge-type and those that display indicative evidence of surging (but have not been observed to surge), we conclude that at least 32.6% of all glaciers in Svalbard surge or are likely to have surged. This study contributes to the understanding of the links between glacier surging and specific landforms/landform assemblages (composite ridge systems and CSR networks), which has applications in other modern glacial environments and at the margins of former ice masses in palaeoglaciological settings.