Soil development in low-arctic tundra of the northern Brooks Range, Alaska, USA

Thirty-six Gelisols were investigated in the vicinity of Galbraith Lake and Toolik Lake (68 degrees 30'N, 149 degrees 30'W) in northern Alaska. The soils formed on surfaces previously interpreted as ranging from similar to 110 ka BP to late Holocene in age. Sixteen of the profiles (44%) contained evidence of cryoturbation and were classified as Turbels, while the others were classified as Orthels. While most of the Orthels are developed in coarse-textured outwash, all of the Turbels are restricted to fine-grained till and colluvium with ice-rich permafrost. There were no significant differences in profile quantities of weathering products, such as H(+) ion, clay, silt, silt-plus-clay, and loss on ignition, between Orthels and Turbels. However, there were significant or nearly significant differences in profile quantities of H(+) ion, silt, and silt-plus-clay as a function of age, with the lowest values in Holocene soils, intermediate values for the two younger drifts, and greater values for the oldest surface. A key finding of this study is that despite pervasive cryoturbation, soil properties can be used to determine relative age in the Low Arctic. Our results confirm previous age estimates that Itkillik II surfaces are of late Wisconsin age, with Itkillik I surfaces being somewhat older.