Aeolian accumulation rate within the kettle holes on Skeiðarársandur (S Iceland) under climate warming conditions.

Abstract

Like other higher latitudes, Iceland is experiencing climate warming, leading to glacier retreat and the formation of new plume areas of aeolian material - vast deserts, including the Skeiðarársandur outwash plain. The main objective was determining the annual rate of aeolian accumulation within glacial flood-origin sandur kettle holes as important sediment traps. The analysis was based on data collected in 2021/2022-2023/2024, at an older level, in depressions after 1892 and 1934/1938 glacial lake-outburst floods, and at a younger level, after the catastrophic jökulhlaup of 1996. Meteorological data, digital elevation models, satellite scenes and photogrammetric data were also used to examine the role of wind, morphometry of kettle holes, and plant coverage in the aeolian accumulation rate and to validate the monitoring results. Analysis showed that the material collected in the kettle holes was of local origin. On the younger level, without vegetation or an initial succession, particle transport occured mostly via saltation (63-75%), and the aeolian aacumulation rate averaged 5,000-7,400 g m^-2 yr^-1 (50% between 3,600 and 13,400 g m^-2 yr^-1). It is several times higher than on the flat sandur surface and 6-44 times higher than on the older level, completely covered with vegetation, and more distant from plume areas. Mineral particles here were finer and transported mainly in suspension (50-85%). Identifying aeolian facies and particle characteristics within the analogous Pleistocene sandur kettle holes of the glacial lake-outburst flood-origin in the European Lowland may indicate the time of their formation caused by climate warming, the Scandinavian Ice Sheet decay, and the transformation of ecosystems from tundra to forest.