AN INVESTIGATION OF WEATHERING IN SOME ARCTIC‐ALPINE SOILS ON THE NORTHEAST FLANK OF OKSSKOLTEN, NORTH NORWAY¹

Abstract

Morphological. particle sizc and mineralogical analyses of three soils iiidicate that the degree of weathering during pedogenesis has been of a low order. Textural characteristics and mineral content variations are attributed largely to inheritance from the till parent material, rather than to pedological processes. These observations suggest that frost action as a soil weathering process in this particular environment is minimal. Hydration and dissolution by chelation are discussed as possible alternative mechanisms, but their operation is probably impaired by restricted water availability resulting from the extensive duration of seasonally frozen ground conditions. lntroducrion THE only known detailed investigation of weathering in high altitude soils of Norway is a study of the sand fractions of two profiles from Trollheimen by Holtedahl (1953) (Fig. I). He concluded that the soils were o f different origins, one having formed by in sifu weathering of bedrock and the other having developed on a till deposit. The principal weathering processes operating were considered to be chemical alteration of hornblende, recognized in thin section, and frost shattering, although no convincing evidence for this process was presented. It is the objective of the present investigation to examine further the nature and intensity of weathering in Norwegian mountain soils, selecting for analysis three profiles developed under contrasting environmental conditions at Okstindan (Fig.

Differential weathering of feldspar and pyroxene in an arctic‐alpine environment

“…The minimum rates of weathering presented here are lower than rates of surface lowering measured on other lithologies and in other environments (Table 11). However, they are much higher than have been reported previously from Jotunheimen (Mellor, 1986a(Mellor, , 1986b and from similar arctic-alpine soils in north Norway (Ellis, 1980).…”

“…At an altitude of 1400 m, the site lies within the mid-alpine belt (Dahl, 1975). Mean annual temperature and rainfall are estimated as -3.5"C (Matthews, 1987) and about 900 mm (Erikstad and Sollid, 1986). Messer (1 984) described the soils of Leirdalen as arctic-alpine Brown Soils (Ellis, 1979), corresponding approxirnately to the Cumulic Regosols of the soil classification proposed by the Canada Department of Agriculture (1970) and to the Lithic Cryorthod class of the 7th Approximation system of the United States Department of Agriculture ( 1 975).…”

“…The conclusion that chemical weathering is relatively unimportant in arctic-alpine soils is often based upon the small amount of clay present. However, chemical dissolution does not always result in the formation of free clay minerals (Dixon et al, 1984;Fritz, 1988). Insoluble weathering products may be in the form of amorphous gels (Jones and Wilson, 1985) or of layer silicates which join coherently to the parent mineral structure (Eggleton, 1986;Eggleton and Boland, 1982).…”

Arctic‐alpine brown soils as a source of palaeoenvironmental information: Further 14C dating and palynological evidence from Vestre Memurubreen, Jotunheimen, Norway

“…In the A horizon, the finer than 2mm fraction is dominated by fine sand and coarse silt (2Cb200 ym), which comprise 67% of the soil matrix. Given the low degree of weathering of soils in this and similar arcticalpine environments (Ellis, 1980b(Ellis, , 1983Mellor, 1984), the high concentration of fines would appear to have resulted from surface accumulation. Till surfaces and outwash plains in front of Vestre Memurubreen are likely, moreover, to have provided a ready source of aeolian particles throughout much, if not all, of the period of soil development.…”

Long-Term Mammalian Herbivory and Nutrient Addition Alter Lichen Community Structure in Alaskan Dry Heath Tundra

“…Almost all the plants in the Arctic are slow-growing perennials that are adapted to survive stressful abiotic limitations such as low mean annual temperature and precipitation, a short growing season, soil moisture extremes, and low soil nutrient availability (Babb and Whitfield, 1977;Chapin et al, 1978Chapin et al, , 1987Ellis, 1980;Billings, 1987). These conditions are not favorable to the metabolic processes of soil microorganisms (Bliss, 1962;Clein and Schimmel, 1995;Mikan et al, 2002); therefore, while total stocks of N and P in soils may be substantial, a large proportion is bound in organic forms not directly available to plants Billings, 1987;Chapin et al, 1995).…”