Soils and landscapes of Karkevagge, Swedish Lapland

Karkevagge, a glacially eroded valley above the Arctic Circle in Sweden, is of particular interest because research findings there in the 1950s challenged the view that chemical weathering is insignificant in cold climates. Because of the wide elevation range, diverse landscapes, steep slopes, and proximity to tree line, soils in the watershed are quite variable and recent changes to Soil Taxonomy have complicated the classification of cold soils. This paper presents an overview of our findings based on 37 pedons. Research site elevations ranged from 505 to 1585 m and slopes from 1 to 78%. Mean annual soil temperatures (MAST), based on a 1- to 2-yr record, ranged from 2.5 to -3.4°C. Although MAST was <0°C at sites above 1200 m, Gelisols were not found below 1500 m because estimated depth to permafrost exceeds 2 m, a critical boundary in the new Soil Taxonomy. The common mineral soils can be divided into four groups on the basis of elevation and landscape position: (i) Haplocryods at low elevation and on more stable landscapes; (ii) Cryofluvents within the valley on slopes <25% and on flood plains; (iii) Cryorthents at higher elevations and on steeper slopes; and (iv) Dystrocryepts on the gently sloping ridge tops where depth to permafrost presumably exceeds 2 m. Other soils identified include Cryosaprists in isolated bedrock depressions at lower elevations and a Mollisol, perhaps the most northern in the world. The soils are typically coarse-loamy with <5% clay. Coarse fragments are common, ranging up to 68% by volume, most are channers derived from the local mica schist. The soils are micaceous, again reflecting the geology. Soil pH tended to be slightly acidic except near marble bedrock outcrops, which, along with the presence of interstratified minerals, demonstrates the importance of chemical weathering and pedogenesis in this arctic environment.