Comparison of geochemical characterization derived from geological versus subsolum geological substrate maps as basis for soil formation in Austria

Parent material for soil formation (subsolum geological substrate, SSGS), represents an essential link between geology and soil science. This study evaluates the applicability of geological and SSGS maps for understanding soil formation processes in Austria. Geochemical characterization derived from traditional geological maps at scales 1:200.000 and 1:50000 are compared with a novel SSGS map based on a recent mapping campaign. The analysis focuses on the geochemical characteritics based on mineral components including carbonates, silicates and clay minerals, and its genesis and/ or deposition type, which have significant influence on pedogenesis.

The comparison reveals that geological maps often overlook surficial sedimentary deposits, such as quaternary loess deposits, which are crucial for understanding soil formation and plant growth. For example, surficial carbonate free rocks covered by carbonate substrates or vice versa result in entirely different soil characteristics, therefore soil development processes and related nutrient capacity. Furthermore, the geochemical evolution from geological bedrock to SSGS in areas of autochthonous weathering may reveal distinct shifts in mineral composition and geochemical properties, underscoring the transformative processes involved in soil genesis.

The study spans large parts of eastern Austria, including major tectonic units of the alpine region and its foreland basins, encompassing crystalline, sedimentary and Neogene rock formations.

These findings underscore the importance of SSGS maps for improving our understanding of soil formation, plant nutrient supply and ecosystem modeling.