Pleistocene paleosols in Norway: implications for past climate and glacial erosion

Abstract

As recently as 7 years ago Quaternary geologists believed that there were no Pleistocene paleosols represented by non-peaty soil horizons (A, B, etc.) in Norway. However, several buried soils of this type have recently been reported and studied by stratigraphic, magnetic and chemical methods. Magnetic susceptibility is a useful method for identifying and correlating paleosols, even in areas of complex glacial stratigraphy such as the Nordic countries. At Sargejohka in Finnmark, up to seven different buried pedocomplexes are separated by tills and glaciotectonic deformation structures. They represent different periods of land surface stability and, with two possible exceptions, are not pseudosoils formed by a fluctuating groundwater table. The most important from stratigraphic and paleoclimatic points of view is a well-developed red–yellow paleosol numbered p3 counting down from the top. It is thought to be a podzol of the last interglacial. Later cryoturbation of pre-Mid Weichselian age has greatly altered its upper part, indicating a dramatic change in climate after development of the soil. At Lillehammer in southeastern Norway, remains of the oxidised zone of a buried paleosol, also thought to have formed mainly in the last interglacial, occur in an inferred Saalian till. The presence of buried Pleistocene paleosols in the interior of Norway (central part of the Fennoscandian glaciations) indicates that glacial erosion was locally less during several glacial cycles than previously thought.