How does climate seasonality influence weathering processes in badland landscapes?

Abstract

An intricate association between weathering and erosional processes is largely controlled by climate disparities. Weathering as a predisposing process for natural hazards, landform evolution, and sediment mobility, hosts key uncertainties in our understanding of how climate controls differential weathering types and rates. Here, we investigate how weathering is influenced by seasonal changes in precipitation and temperature in badland landscapes. Previous studies have commonly adopted rainfall simulation approach in the field or laboratory, but have simulated only steady climate conditions to understand weathering dynamics. Taking these studies further, we simulated seasonal changes in precipitation and temperature in the laboratory. To understand their weathering response, we exposed samples collected from four different climates over twelve sequential seasons, reflecting a 3-year period. We used pH, electrical conductivity (EC), ion concentrations, and surficial changes as chemical and physical proxies, respectively, to infer types and trends of weathering. Based on the influence of sediment physicochemical properties (especially high sodium absorption ratio (SAR)) on weathering processes, our findings reveal that sinusoidal trends attaining their peak level in spring in Na+ concentration, which overcomes other ions, contribute to an accelerated dispersion degree with concurrently decreasing pH in marly sediments in the Arid region. Moreover, the recurrent pattern of increased Ca2+ levels, especially during winter seasons, can enhance the extent of sediment aggregations within Mediterranean sandy mudstones. In conclusion, consistent with previous studies, wetting–drying cycles are crucial in physical weathering and regolith behavior, which resulted in cyclic deep crust formations in the spring and summer seasons due to the high swelling capacity of samples. Overall, this study demonstrates how seasonal changes in climate regulate the degree of chemical and physical weathering processes in badland landscapes.