Annual moraine ridges in Tempelfjorden, Spitsbergen

Abstract

Surging tidewater glaciers produce a characteristic landform assemblage with glacial lineations, networks of crevasse-fill ridges, large terminal moraine ridges and several recessional moraines, which often override glacial lineations (Solheim 1991; Ottesen et al. 2008). Submarine recessional moraines have also been mapped beyond several Svalbard tidewater glaciers and are interpreted to record an annual to semi-annual signal of glacial retreat during the quiescent phase of the surge cycle (Ottesen & Dowdeswell 2006; Ottesen et al. 2008). The moraine ridges probably form during winter stillstands or minor readvances of the glacier terminus (Boulton et al. 1996; Ottesen et al. 2008). Tunabreen is a tidewater glacier of surge type located in Tempelfjorden, Spitsbergen (Fig. 1e). It has surged three times since the Little Ice Age, in 1930, 1970 and between c. 2002 and 2005 (Forwick et al. 2010) producing large terminal moraines (Fig. 1a). During the latest surge, the glacier margin reached its maximum extent in 2004 and has since retreated about 1 km. Fig. 1. Multibeam-bathymetric images of Tempelfjorden, Svalbard. Image courtesy of the Norwegian Hydrographic Service (permission no. 13/G706). ( a ) Image of inner Tempelfjorden, superimposed on an aerial image from 2009 (Photo …