Sediment runoff formation in a small periglacial catchment on the King George (Vaterloo) island, Antarctica

Abstract

Global climate change has most significantly affected the Polar Regions. The increase in air temperature has stimulated the melting of glaciers in the Arctic and Antarctic, which has contributed to changes in the formation of water and sediment runoff. However, there are very few quantitative estimates of the sediment redistribution in the periglacial catchments of the Polar Regions. Specific features of water and sediment runoff were studied within the catchment area of the Korabelnyj Stream located on the Fildes Peninsula in Antarctica near the Bellingshausen Ice Dome. The main aim of the study was to investigate the conditions for the formation of water and sediment runoff and to identify the proportional contribution of washout and erosion material coming from the periglacial and maritime parts of the catchment area to the sediment runoff of the stream. A set of methods and approaches, including: a) estimates of the sediment flow connectivity index; b) fingerprinting technique; c) hydrometeorological observations; d) large-scale geomorphological survey and others, was ap[1]plied to identify the conditions for the formation of surface runoff and washout, the mechanisms of sediment redistribution in various parts of the fluvial network and to quantify the proportional contribution of two main sediment sources to the sediment runoff of the stream. A fraction with a particle size of ≤63 μm was used for geochemical and spectrometric analyzes of soils and sediments. In total, the content of 34 elements was analyzed, i.e. 6 radioisotopes and 28 stable elements. It has been established that despite the significant differences in the relief of the near-glacial and maritime parts of the catchment area, the indices of sediment connectivity are quite close and amount to –1,79 and –1,35, respectively. A significant part of the material transported by temporary streams from the slopes of the catchment area is redeposited in relief depressions partially occupied by water bodies. The main volume of sediments, which is at least 60–66% of the total sediment runoff in the outlet section of the Korabelnyj Stream, comes from the periglacial part of the catchment area. This is due to the increased water discharge relative to the non-glacial part of the catchment area, which results from the melting of snow and ice accumulated on the ice dome, the high erosion of moraine deposits unprotected by vegetation, and the presence of an ice core in moraines, which prevents water filtration.