Badlands and environmental change

Abstract. Badlands develop in many climatic regions, on a wide range of soils and in various bedrock types. The physical triggers for development of badlands can be natural, such are tectonic activity and climate change, but more frequently they are human induced, e.g. land clearance to change use of land. The research presented here clearly indicates that clay mineralogy and type and amount of clay in the bedrock play a critical role in the development of surface crust and hillslope morphology and ultimately of badlands. Laboratory experiments on smectite-rich samples subjected to simulated rainfall have established a correlation between phased development of surface crust and desiccation cracks and duration of rainfall. A similar correlation could not be found for smectite-poor materials. In addition, evidence was collected on the different responses of smectite-rich and smectite-poor lithologies to wetting and drying periods. Thus, it appears in particular that drying periods play an important role in badland development on smectite-rich materials, an aspect which is directly linked to slope orientation and strongly sensitive to differences that occur with sensu stricto seasonal climatic changes.