Co-evolving delta faces under the condition of a moving sediment source

A fan delta developed under the constraints of a moving point of flow-sediment supply is described. The sediment mixtures used in the experiments were chosen to approximate field conditions, with the coarser fractions depositing to form the topset (subaerial delta surface) and foreset, and the finer fractions forming a turbidity current that plunges near the shoreline, overrides the foreset, and continues into deeper water to emplace a bottomset. The migration rate of the feed point was adjusted so that the base of the lateral foreset along one side just touched the flume wall, so leaving open water on that side. The experiments provide insight into the sedimentation processes associated with these three co-evolving structures of the delta, i.e. its topset, foreset, and bottomset. The results indicate that the lateral delta extent can be controlled via the downstream migration of its sediment source.