Chemical Weathering Rates and Geochemical-Mineralogical Characteristics of Soils Developed on Heterogeneous Parent Material and Toposequence

Abstract

Mineral weathering is an environmentally significant process and stage in the formation of soils. In addition, soil formations are highly associated with topographic positions that have influence on the morphological, mineralogical, and weathering processes of the soils. That is because topography or relief affects how water and other materials are added to and removed from soils. The aim of this study was to carry out a pedological evaluation of the soils classified as vertisols, inceptisols, and entisols by taking into consideration a soil taxonomy classification system based on different topographic positions and the same parent rocks. The second aim of this research was to answer questions about the differences in classification resulting from pedogenic processes or from other factors by quantifying the maturity stages and the degree of soil weathering using geochemical, mineralogical, and other analytical data. To accomplish this, after macro-morphological identifications were completed for three representative soil pedons, soil samples were collected from the horizons to investigate analytical characteristics such as mineralogical, geochemical, and physicochemical properties. The study took into account other features, including the pedogenic evolution of soils using weathering indices such as CIA, CIW, Base/R2O3, WIP, and PIA. The results showed clearly that topographic conditions strongly affect soil physicochemical, mineralogical, and morphological properties, either directly or indirectly in the local region. That conclusion was also supported by chemical weathering indices in this study.