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

Abstract

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 igh rctic. 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 pitsbergen. More than 600 m 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.

Key words:

• cold glaciers
• englacial/subglacial conduit
• glacier hydrology
• glacio‐speleology
• icings
• Svalbard

Acknowledgement

KN was funded by an Arctic Field Grant from the Research Council of Norway, the Swiss Society for Speleology and the travel grant commission of the Swiss Academy of Science. HL was funded by a NERC PhD studentship (NE/I528050/1), the Queen Mary Postgraduate Research Fund and an Arctic Field Grant from the Research Council of Norway. Landsat satellite images were provided by USGS Earth Explorer and aerial photographs were acquired from the Norsk Polarinstitutt. Fieldwork support from the Logisitics Department of the University Centre in Svalbard was vital and we are grateful to E. Fleming, B. Hubbard, N. Hulton and Ph. Schuppli for their contributions to the collection of field data, and to all members of AG‐325 in 2011, who were present when the cave systems of Tellbreen were first discovered. The photograph reproduced in Figure 5k was taken by E. Welty. We thank W. Haeberli for the stimulating discussion of the glaciological features and M. Huss, L. Sold, M. Fischer and two anonymous reviewers for their detailed and thoughtful manuscript review.

Additional information

Notes on contributors

Kathrin Naegeli

Kathrin Naegeli, Department of Geosciences, University of Fribourg, Chemin de Musée 4, 1700 Fribourg, Switzerland

E‐mail: [email protected]

Harold Lovell

Harold Lovell, Department of Geography, University of Portsmouth, Buckingham Building, Lion Terrace, Portsmouth PO1 3HE, UK

E‐mail: [email protected]

Michael Zemp

Michael Zemp, Department of Geography, University of Zurich – Irchel, Winterthurerstrasse 190, 8057 Zürich, Switzerland

E‐mail: [email protected]

Douglas I. Benn

Douglas I. Benn, Arctic Geology, The University Centre in Svalbard (UNIS), PO Box 156, N‐9171 Longyearbyen, Norway

E‐mail: [email protected]