Water-soluble chemistry and weathering characteristics of some tills in Western Dronning Maud Land, Antarctica

Abstract

The water-soluble chemistry and weathering characteristics of tills were studied on three nunataks with differing bedrock characteristics in the Vestfjella and Heimefrontfjella areas of the Western Dronning Maud Land, Antarctica. The chemical analyses were performed using ion chromatography and ICP-AES. The relative weathering characteristics of the till surface boulders was assessed in study locations. No colour differences were observed in test pits dug in Basen and Utpostane nunataks at Vestfjella, whereas the till in Mygehenget nunatak at Heimefrontfjella has a pronounced soil profile in which the surface part has a banded rusty brown and light-coloured accumulations. The highest concentrations of readily soluble ions were recorded in the Mygehenget samples characterized by high (SO4)2- (5800-39000 ppm) and Mg concentrations (540-6000 ppm), while the Basen samples had the highest concentrations of Fe2+(23-390 ppm), Al3+ (60-1000 ppm) and Si4+ (23-1700 ppm) and the Utpostane samples the lowest ones. The SO4/Na+, Na+/CI- and Mg2+/Na+ ratios for the samples differ markedly from those typically encountered in sea water. The presence of the highest concentrations of many of the analysed ions in the Mygehenget soil samples is in line with the advanced weathering of the surface boulders. The high Fe2+, Si4+ and Al3+ concentrations in the Basen samples may be attributable to the weathering of olivine alteration products.

Keywords

• soils
• till
• chemical composition
• ions
• pH
• nunataks
• weathering
• Queen Maud Land
• Antarctica