Chemical weathering indices in contrasting fluvial systems: a comparative study from the Lublin Upland and the Sudetes Mountains in Poland

Abstract

The chemical weathering indices in different fluvial systems in Poland are determined, to indicate which factors affect small-scale chemical weathering processes to the greatest degree. The Weathering Index of Parker (WIP), Vogt’s Residual Index (V), the Chemical Index of Alteration (CIA), Harnois’s Chemical Index of Weathering (CIW), and the Plagioclase Index of Alteration (PIA), as well as Rb/Sr and Sr/Cu ratios, were calculated for 30 sediment samples taken from four selected rivers in the Lublin Upland and the Sudetes Mountains, respectively. The median values for the Lublin Upland rivers were as follows: WIP (12.14–13.05), V (0.66–0.83), CIA (31.79–33.93), CIW (36.67–38.07); PIA (25.20–29.84), Rb/Sr (0.32–0.41), Sr/Cu (14.01–19.66). The median values obtained in the Sudetes Mountains were: WIP (49.88–56.25), V (2.03–2.70), CIA (54.73–56.63), CIW (68.60–70.59), PIA (58.48–59.59), Rb/Sr (1.13–2.70), Sr/Cu (5.94–8.14). River sediment samples were also analysed using a scanning electron microscope and XRD diffraction of whole rock samples to identify minerals hosting the elements investigated. The results indicate a higher intensity of weathering processes in the Sudetes Mountains than in the Lublin Upland and corroborated that, besides the climate regime, other factors, such as bedrock lithology, physical erosion and landform type have significant meaning in assessing weathering processes.