Variations in grain-size distribution of suspended sediment in a glacial meltwater stream, Austre Okstindbreen, Norway

Abstract

Thirty-nine samples of suspended sediment from the meltwater stream of Austre Okstindbreen, Norway, were analysed using both moments and parameters of the hyperbolic distribution. The samples turned out to be non-normally distributed. No direct correlation was found between discharge and grain-size distribution, but it is supposed that the hydraulic influence is hidden behind factors like composition of morainic or stream-bed material. Through comparison of the grain-size parameters from two periods in the field season, it was possible to distinguish between two sediment populations.

Correlations of suspended sediment size with bedrock lithology and glacier dynamics

“…Pandey and others, 2002; Haritashya and others, 2010). As a result, we avoid direct comparison with other studies, as suggested by Karlsen (1991).

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“…As mentioned above, the SSSD could be a function of till deformation processes; till deformation in turn depends on glaciological variables such as basal shear stress and effective pressure. Alternatively, the SSSD may simply reflect the natural sampling of sediment by the evolving subglacial drainage system (Karlsen, 1991; Humphrey and Raymond, 1994; Thayyen and others, 1999). During the 1982/83 surge of Variegated Glacier, a fining of grain sizes was observed with an increase in sliding speed (Humphrey and Raymond, 1994).…”

“…In glacial systems, the SSSD likely depends on the size distribution of the sediment source and the transport capacity of the stream (e.g. Karlsen, 1991). Seasonal glacier dynamics may also play a role as changes in the subglacial drainage morphology lead to changes in the SSSD (e.g.…”

Oxygen isotopes in glacier-river water, Austre Okstindbreen, Okstindan, Norway

“…Generally, the northern river was the larger, but the southern one was the principal outlet for water throughout the summers of 1978 and 1981, and in the early part of the 1985 summer. In that year, drainage was disrupted during a mid-summer storm, after which the northern river was dominant (Karlsen, 1991). In 1987, no water issued from the southern side of the glacier, and in all subsequent summers only one river has discharged from its front.…”

The use of planimetric surface area in glacier mass-balance calculations: a potential source of errors

“…In addition to annual mass-balance determination (Knudsen, 1994), the programme has included observations of surface flow of the glacier (Andreasen and Knudsen, 1985), basal sliding (Andreasen, 1983), the movement of water through the glacier (Theakstone and Knudsen, 1981, 1989), drainage of a glacier-dammed lake (Knudsen and Theakstone, 1988). the chemical composition of the river water issuing from the glacier (Theakstone, 1988; Theakstone and Knudsen, in press), suspended-sediment concentrations in the glacier river (Karlsen, 1991) and the chemistry of the snow cover (Raben and Theakstone. 1994).…”