Local Buffers to the Sediment Cascade: Debris Cones and Alluvial Fans

Major interruptions to the sediment cascade occur at a variety of temporal and spatial scales, ranging from small, short-term and ephemeral zones of deposition to larger more persistent features in the landscape. Sediment storage zones often occur at changes or breaks in the boundary conditions of the sediment pathway. Such zones are characterized by distinctive landforms (debris cones and alluvial fans) and have important effects on the dynamics of the system, which produce 'coupling or buffering' relationships within the sediment pathway. To understand sediment flux through alluvial-fan and debris-cone environments requires consideration of the controls involved, their spatial–temporal relationships and their relations with an absolute chronology. Past research has followed separate lines focusing on geology and sedimentology, with emphasis on tectonic controls, or on geomorphology, with emphasis on climatic controls. More recent approaches allow a quantitative treatment of debris cones and alluvial fans as part of a continuum within the sediment cascade.