Colluvial deposits and slope instability

Slope instability results from the interplay between tectonic uplift, climatecontrolled weathering, and slope form (relief). Sediments accumulate as colluvium on footslopes when under the influence of gravity, fluvial processes and mass movements, and may be affected by pedogenesis, ecosystem change and human activity. This chapter shows that colluvial form and stratigraphy cannot be uncritically assigned to particular late Pleistocene and Holocene climatic periods, because of the feedbacks associated with weathering rate, vegetation responses to climate, and slope angle. Moreover, land surface instability and colluvial formation/incision is taking place due to contemporary environmental degradation, closely related to overgrazing.