Variations of soil profile characteristics due to varying time spans since ice retreat in the inner Nordfjord, western Norway

Abstract

Abstract. In the Erdalen and Bødalen drainage basins located in the inner Nordfjord in western Norway the soils were formed after deglaciation. The climate in the uppermost valley areas is sub-arctic oceanic, and the lithology consists of Precambrian granitic orthogneisses on which Leptosols and Regosols are the most common soils. The Little Ice Age glacier advance affected parts of the valleys with the maximum glacier extent around AD 1750. In this study five sites on moraine and colluvium materials were selected to examine main soil properties, grain size distribution, soil organic carbon and pH to assess if soil profile characteristics and patterns of fallout radionuclides (FRNs) and environmental radionuclides (ERNs) are affected by different stages of ice retreat. The Leptosols on the moraines are shallow, poorly developed and vegetated with moss and small birches. The two selected profiles show different radionuclide activities and grain size distribution. The sampled soils on the colluviums outside the LIA glacier limit became ice-free during the Preboral. The Regosols present better-developed profiles, thicker organic horizons and are fully covered by grasses. Activity of 137 Cs and 210 Pb ex concentrate at the topsoil and decrease sharply with depth. The grain size distribution of these soils also reflects the difference in geomorphic processes that have affected the colluvium sites. Significantly lower mass activities of FRNs were found in soils on the moraines than on colluviums. Variations of ERN activities in the valleys were related to characteristics of soil mineralogical composition. These results indicate differences in soil development that are consistent with the age of ice retreat. In addition, the pattern distribution of 137 Cs and 210 Pb ex activities differs in the soils related to the LIA glacier limits in the drainage basins.

Sediment sources, spatiotemporal variability and rates of fluvial bedload transport in glacier-connected steep mountain valleys in western Norway (Erdalen and Bødalen drainage basins)

“…1 and 2) (Beylich et al, 2009Laute and Beylich, 2010, 2014aBeylich andLaute, 2012a,b, 2014;Liermann et al, 2012;Decaulne et al, 2013Decaulne et al, , 2014Navas et al, 2014). Fluvial bedload transport observations as part of the ongoing geomorphic process studies have been carried out in selected stream channel reaches within these supply-limited drainage basin systems.…”

Preface: Soil processes in cold-climate environments

“…The chemical signature of the soils may change with time (Navas et al, 2008). In this sense, Navas et al (2014) show how the study of the fallout radionuclides and environmental radionuclides in soil profiles in recently deglaciated environments can reveal patterns of ice retreat. The study case for western Norway, an area with a large amount of information about historical glacier dynamics (Nussbaumer et al, 2011), can be therefore applied to other glaciated environments with little information about recent evolution from other proxies.…”

“…The influence of cold climates on the soils is reflected in the thermal regime of the ground, which controls the typology and processes affecting the soils As a result of the International Polar Year (2007, there has been a significant increase in the number of papers focusing on permafrost environments. Major interest has been given to the monitoring of the thermal state of the permafrost in the Arctic (Romanovsky et al, 2010), where the recent warming may impact the dense network of settlements and infrastructures allocated there (Nelson et al, 2002). Despite the complex lo-gistics in Antarctica, there has been an increased effort in creating a network for permafrost monitoring in this continent (Vieira et al, 2010;Bockheim et al, 2013).…”

“…-characterization of physical and chemical properties of the soils (Navas et al, 2014;Palazón et al, 2014);…”