Study Area

Disko Island (70° N, 54° W) is situated in central West Greenland (Figure 1). The island is the largest in Greenland and covers 8575 km2 of which about 19% is glacierized (Humlum, 1987). According to the regional glacier inventory (Weidick et al, 1992), the island contains 1070 glaciers, ice and snowfields of which 350 are larger than 1 km2. Of these, 247 are glaciers, while the remaining comprises ice and snowfields. From the two major ice caps,

Sermersuaq (Storbraen) and Brapasset, in the central part of the island, outlet glaciers extend into the characteristic U-shaped valleys that drain meltwater to the large fjords and the Disko Bay. All glaciers on Disko Island terminate on land, and there are no indications of glaciers reaching the sea during the Little Ice Age (LIA), except for some rock glaciers.

The climate is polar maritime with discontinuous permafrost along the southern and western coastal areas, whereas the central and northeastern parts of the island have colder continental climate with continuous permafrost (Humlum, 1999; Yde and Knudsen, 2007). The 1961-1990 mean annual air temperature in the coastal town of Qeqertarsuaq (Godhavn) was -4.0°C (Humlum, 1999), and it is about 3°C colder at sea-level in the central part of the island (Humlum et al, 1995).

Figure 1. Location map of Disko Island, West Greenland

The geology is characterised by Early Tertiary basalt plateaux at 600-1200 m a.s.l. with numerous glacier-carved cirques (Pedersen, 1977; Piasecki et al., 1992). The lowest layers of basalt lava have intercalated layers of contemporary shale. In the eastern part of Disko Island, the Tertiary basalt overlays Paleocene sand- and mudstones of the Atanikerluk Formation and Cretaceous sandstones of the Atane Formation (Pedersen et al., 2001). Both of these formations contain coal seams. The basement comprises the Precambrian north-south striking Disko Gneiss Ridge, which only is exposed at Qeqertarsuaq and in some of the central fjords. Many homothermal (3-12°C) springs are situated at the interface between gneiss and the overlying rocks.

Information on 19th-century and early 20th-century glacier fluctuations on Disko Island was compiled from expedition accounts, drawings, maps and photographs (Yde and Knudsen, 2007). Remote sensing data were obtained from a 1931-33 topographic map (GID, 1941) covering the south and central part of the island, aerial photographs from 1953-54, 1964 and 1985, and satellite images from 1973 (Landsat 1 Multispectral Scanner (MSS)), 1976

Figure 1. Location map of Disko Island, West Greenland

100 km

100 km

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