The distribution of different glacial landscapes on southern Jameson Land, East Greenland, according to Landsat Thematic Mapper Data

Abstract

Four geologic units previously mapped in southern Jameson Land. East Greenland (Funder 1978, 1990) are identifiable on a false colour composite of Landsat Thematic Mapper (TM) spectral hands TM5. TM4 and TM1. The area covered by the Weichselian glaciations has a fresh glacial morphology and a less developed drainage system than the older landscape. The Weichselian glaciers reached more than 200 m a.s.l. in the west. but only about 100 m a.s.l. in the east. A contextual analysis (local frequency and local orientation) was included in a Maximum Likelihood classification (M‐L) to map the extent of the Weichselian glaciations. Deposits correlated with the Saalian Scoreshy Sund glaciation are found on the central plateaux of Jameson Land. Landsat TM geological mapping of the surficial distribution of deposits from the Scoreshy Sund glaciation and of weathered Jurassic sandstone or deposits with a high percentage of such sandstone was done using a supervised Maximum Likelihood procedure. Except for the mapping of thc extent of the Late Weichselian Flakkerhuk glaciation, the Maximum Likelihood boundaries between units are in general agrecnient with earlier mapping or with the visual interpretation of the false colour composite. A strong vegetational influence. and similar spectral reflectance lrom deposits of different age due to similarities in lithological composition reduced the possibility of an independent remote sensing approach. Taking already existing general geological knowledge and chronology into account allowed successful Landsat TM geological mapping.

Late Pleistocene glacial history of Jameson Land, central East Greenland, derived from cosmogenic10Be and26Al exposure dating

“…Two areas covered by Late Pleistocene glacigenic sediments have been described on Jameson Land; the ‘older drift’ and the ‘younger drift’ (Ronnert & Nyborg 1994). The former has been mapped on the upland plateaus on the interior of the peninsula (Möller et al 1994), the latter on low elevation areas bordering Scoresby Sund (Ronnert & Nyborg 1994) (Fig. 1).…”

“…1). Between these two regions is the so‐called ‘drift‐less area’, where weathered sandstone is exposed and glacial deposits only occur as scattered erratics and more rarely as thin patches of till (Hjort & Salvigsen 1991; Ronnert & Nyborg 1994).…”

“…This chronology was based on the intense bedrock weathering of interfjord uplands along the northeast Greenland coast, and infinite 14 C dates from raised marine deposits north of Jameson Land were used to put minimum constraints on this glaciation (Funder & Hjort 1973; Hjort 1981). The ‘Jameson Land Drift’, later referred to as the ‘older drift’ (Ronnert & Nyborg 1994), is found as a continuous sheet on the Central Plateau at 450–500 m a.s.l. and on the J. P. Koch plateau at altitudes >750 m a.s.l.…”

The last glacial cycles in East Greenland, an overview

“…along the northern coast and to the crest of the Flakkerhuk ridge (c. 100 m a.s.1.) on the southern coast, while it probably was somewhat thicker on the south side of Scoresby Sund (Mangerud & Funder 1994;Moller et al 1994;Ronnert & Nyborg 1994;Tveranger et al 1994). The Kap Brewster moraine, a more than 175 m thick and 25 km wide sediment accumulation that crosses the mouth of Scoresby Sund, probably marks the position of the glacier front at the culmination of the Flakkerhuk stade ( Fig.…”

10Be data from meltwater channels suggest that Jameson Land, east Greenland, was ice-covered during the last glacial maximum

“…South of the plateaus there are extensive areas with exposed weathered Jurassic sandstone, most of which are concentrated along the middle Fynselv River and its tributaries ( Fig. 1c; Schunke, 1986;Hjort and Salvigsen, 1991;Möller et al, 1994;Ronnert and Nyborg, 1994). We here focus on an interfluve plateau bounded by the deep canyons of the Fynselv River to the east and by one of the Fynselv tributaries to the west (Figs.…”