JOURNAL OF QUATERNARY SCIENCE (2002) 17(3) 201–209 Copyright  2002 John Wiley & Sons, Ltd. Published online 10 April 2002 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jqs.673 Formation and reorientation of structure in the surge-type glacier Kongsvegen, Svalbard JOHN WOODWARD, 1 * TAVI MURRAY 1 and ANDREW MCCAIG 2 1 School of Geography, University of Leeds, Leeds LS2 9JT, England 2 School of Earth Sciences, University of Leeds, Leeds LS2 9JT, England Woodward, J., Murray, T. and McCaig, A. 2002. Formation and reorientation of structure in the surge-type glacier Kongsvegen, Svalbard. J. Quaternary Sci., Vol. 17 pp. 201–209. ISSN 0267-8179. Received 9 September 2001; Revised 18 January 2002; Accepted 22 January 2002 ABSTRACT: 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 ridges 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. Copyright  2002 John Wiley & Sons, Ltd. Journal of Quaternary Science KEYWORDS: surge-type glacier; crevasse-fills; structural glaciology; Svalbard. Introduction Surge-type glaciers oscillate between short periods of extremely rapid movement and long periods of relative inac- tivity or quiescence (Post, 1969). Studies of glaciers during surge suggest that fast flow is associated with basal condi- tions (Clarke et al., 1984; Kamb et al., 1985; Raymond, 1987; Fowler 1987). In the case of surge-type glaciers overlying a sedimentary bed, a rapidly deforming, saturated, sediment sub- strate may induce and/or support surging (Clarke et al., 1984). This same process is thought to sustain the fast-flowing ice streams of Antarctica, which are underlain by water-saturated sediments (Alley et al., 1987; Kamb, 1991; Smith, 1997). The availability of sediment at the bed of a glacier may, thus, have an influence on surge-conditions. * Correspondence to: Dr J. Woodward, Department of Geography and Earth Sciences, Brunel University, Uxbridge, Middlesex UB8 3PH. E-mail: john.woodward@brunel.ac.uk Contract/grant sponsor: Royal Society. Contract/grant sponsor: University of Leeds. A number of recent studies have attempted to identify sedimentary landforms in proglacial environments that are diagnostic of surge conditions (e.g. Sharp, 1985a; Hambrey and Huddart, 1995; Bennett et al., 1996; Hambrey et al., 1996, 1997, 1999; Croot, 1988; Hambrey and Dowdeswell, 1997; Glasser et al., 1998; Evans and Rea, 1999). Particular attention has been paid to crevasse-fill structures (Sharp, 1985a,b), thrust features (Lawson et al., 1994; Sharp et al., 1994; Hambrey et al., 1996; Murray et al., 1997, 2000) and fold structures (Glasser et al., 1998; Hambrey et al., 1999). Kongsvegen (78 ° 48’N 12 ° 59’E) is a 27 km long, 189 km 2 surge-type glacier in northwest Spitsbergen, Svalbard (Hagen et al., 1993) (Fig. 1), which currently terminates in a partially grounded and partially calving margin. The grounded section of the glacier forms a cliff-face 5–20 m high running NW–SE for over 1 km along the fjord margin (at 160–185 ° to the ice flow direction). The calving margin is confluent with the principal flow unit of Kronebreen and Infantfonna at the head of Kongsfjorden. During periods of advance the complex is confluent with another stream of Kronebreen to the north of Collethøgda (Kronebreen M). The Kongsvegen flow stream is currently quiescent with a flow rate of 2.88 m yr -1 (Melvold and Hagen, 1998). Kronebreen in contrast, is currently one