Dendritic subglacial drainage systems in cold glaciers formed by cut-and-closure processes

• Published in: Geografiska Annaler: Series A, Physical Geography
• Main Authors: Naegeli, K., Lovell, H., Zemp, M., Benn, D.I.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2014
• Subjects: Cold glaciers; Englacial/subglacial conduit; Glacier hydrology; Glacio-speleology; Icings; Svalbard; Arctic; Tellbreen; glacier; Spitsbergen
• Online Access: https://research-portal.st-andrews.ac.uk/en/researchoutput/dendritic-subglacial-drainage-systems-in-cold-glaciers-formed-by-cutandclosure-processes(935e3efc-3e18-4794-aa06-0149bb241ccc).html; https://doi.org/10.1111/geoa.12059

The routing and storage of meltwater and the configuration of drainage systems in glaciers exert a profound influence on glacier behaviour. However, little is known about the hydrological systems of cold glaciers, which form a significant proportion of the total glacier population in the climate sensitive region of the High Arctic. Using glacio-speleological techniques, we obtained direct access to explore and survey three conduit systems and one moulin within the tongue area of Tellbreen, a small cold-based valley glacier in central Spitsbergen. More than 600m of conduits were surveyed and mapped in plan, profile and cross-section view to analyse the configuration of the drainage system. The investigations revealed that cold-based glaciers can exhibit a dendritic drainage network with supra-, en- and subglacial components formed most likely by cut-and-closure processes as well as surface-to-bed drainage via moulins. Furthermore, we observed that water is stored within the glacier and released gradually via subglacial conduits during the winter months, forming a large and active icing in the proglacial area. The presence of supra-, en- and subglacial components, the surface-to-bed moulin and the dendritic subglacial drainage network suggest that existing models and understanding of the hydrology of cold glaciers needs to be re-evaluated, mostly concerning the different possible pathways and processes that form the hydrological system.