A tidewater glacier landform assemblage in Belcher Inlet, Canadian Arctic

Abstract

Belcher Glacier, a 35 km long tidewater outlet glacier of the 12 000 km2 ice cap on Devon Island (Dowdeswell et al. 2004), is one of the fastest-flowing glaciers in the Canadian Arctic (Van Wychen et al. 2014) (Fig. 1). Belcher Glacier and neighbouring Fitzroy Glacier to the southeast account for about 55% of the iceberg calving loss from the Devon Ice Cap (Van Wychen et al. 2014). The terminus of Belcher Glacier remained relatively stable between the 1960s (light blue dashed line in Fig. 1a) and 2000 (Landsat 7 satellite image in Fig. 1a). In contrast, the unnamed glacier immediately to the north retreated 2 km during this period (Fig. 1a). Belcher Glacier and the unnamed glacier retreated around 500 and 250 m, respectively, between 2000 and 2014 (dark blue dashed line in Fig. 1a). The bed topography of Belcher Glacier, which is around 250 m below sea level at the present-day glacier margin (Fig. 1c) and remains below sea level in the lower 11 km of the glacier, suggests that its terminus region may become unstable in the event of future retreat. Seafloor mapping of Belcher Inlet beyond the termini of Belcher Glacier and the unnamed glacier (Fig. 1a), together with sub-bottom profiling, provide information about the dynamic behaviour of tidewater glaciers. Fig. 1. ( a ) Swath bathymetry of Belcher Inlet, Arctic Canada (acquired in 2006), superimposed on 2000 Landsat 7 satellite imagery. Multibeam acquisition systems Kongsberg EM300 and Kongsberg EM3002S. Frequency 30 and 300 kHz, respectively. Grid-cell size 10 m. Light blue and dark blue dashed lines are terminus positions derived from 1960s and 2014 aerial photographs, respectively. ( b ) Multibeam-bathymetric image of the seafloor immediately in front of Belcher Glacier. ( c ) 2014 airborne radar profile of Belcher Glacier, showing the depth of the …