PROGLACIAL SOIL FORMATION IN THE ANTHROPOCENE: SOIL CHRONOSEQUENCES IN THE SUB TROPICAL ANDES AND ALPS

The formation of new soils after glacier retreat due to climate change can provide insights into the rates of soil formation during the Anthropocene. Recently deglaciated terrains (<150 years) are subject to weathering and pedogenesis because freshly exposed sediments are prone to react readily with the environment. During the first decades of soil genesis, the variability observed relies on the typical CLORPT factors, but geomorphic activity and climate change are rapid and biotic migrations are highly variable. This paper studies the soil properties, composition, geomorphic dynamics, and environmental characteristics of nine chronosequences of deglaciation in the Alps and the Peruvian Andes. Between 2019 and 2020 we collected 189 soil samples within the nine proglacial landscapes and buried 113 temperature sensors. We measured soil organic matter (LOI), nitrogen and carbon content, pH, and bulk density. We also identify the elemental composition by XRF and ICP-AES and mineralogy by XRD of our samples. Our preliminary results show faster SOM accumulation in the Andean proglacial soils than within the Alps. Similarly, higher N and C accumulation are detected in the Andean soils at a similar age. In most sites, we also observe different tendencies over short (35 years) and longer chronosequences (80 or 150 years) and between soil properties. The age factor also affects soil properties differently. Our results suggest that proglacial soil formation is mainly driven by climate and parent material characteristics and we can associate faster soil formation with subtropical climates.