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

a r t i c l e i n f o Along the northeast Greenland continental margin, bedrock on interfjord plateaus is highly weathered, whereas rock surfaces in fjord troughs are characterized by glacial scour. Based on the intense bedrock weathering and lack of glacial deposits from the last glaciation, interfjord plateaus have long been thought to be ice-free throughout the last glacial maximum (LGM). In recent years there is growing evidence from shelf and fjord settings that the northeast Greenland continental margin was more extensively glaciated during the LGM than previously thought. However, little is still known from interfjord settings. We present cosmogenic 10 Be data from meltwater channels and weathered sandstone outcrops on Jameson Land, an interfjord highland north of Scoresby Sund. The mean exposure age of samples from channel beds (n= 3) constrains on the onset of deglaciation on interior Jameson Land to 18.5± 1.3–21.4 ± 1.9 ka (for erosion conditions of 0–10 mm/ka, respectively). This finding adds to growing evidence that the northeast Greenland continental margin was more heavily glaciated during the LGM than previously thought. Introduction Identifying temporal and spatial changes of past ice sheets is critical for understanding their role in the global climate system. Within formerly glaciated regions, the occurrence of highly weathered terrain has often been used as evidence either for the existence of ice-free areas during the last glaciation In recent years, cosmogenic exposure dating methods have provided a new technique to interpret differentially weathered landscapes, which has led to a new understanding of the extent and dynamics of ice sheets (Bierman et al. Along the northeast Greenland continental margin (Fig. 1), from Scoresby Sund and northwards, bedrock on interfjord plateaus is highly weathered whereas rock surfaces in fjord troughs are characterized by glacial scour. Previous work suggested that the different degree of weathering from plateau to fjord exists because interfjord plateaus remained ice-free throughout the last glacial cycle whereas fjords where occupied by outlet glaciers from the ice sheet Based on the intense bedrock weathering and lack of glacial deposits from the last glaciation on interior Jameson Land, the area has long been thought to be ice-free throughout the last glacial maximum The Jameson Land peninsula (70°–71°N) is located at the northern side of Scoresby Sund, the largest fjord system in east Greenland (Fig. 1). The distance between the fjord mouth and the present margin of the Greenland Ice Sheet …