A conceptual framework for the erosion behaviour of sand–mud mixtures

The erosion behaviour of sand–mud mixtures is not well understood. As a first step, a conceptual framework for the erosion behaviour of sand–mud mixtures is proposed and validated with data from field and laboratory experiments based on appropriate parameters for cohesion and network structure. Six bed types with different characteristics are distinguished in relational diagrams. Validation with experimental data shows that observed transitions in erosion behaviour are clearly delimited in these diagrams. Mud content (%<0.063 mm) as a descriptor for the transition between non-cohesive and cohesive erosion behaviour turns out to be less generic than the clay content (%<0.004 mm). Furthermore, an estimation of the relevance of these compositional bed types in natural systems shows that the frequently observed constant ratio between clay and silt in the bed sediments of some depositional system strongly limits the number of relevant bed types in that system.