Incised valley lengthens upstream by headward erosion with attendant flow piracy. Downstream the valley lengthens by forced regression. Incised valley lengthens upstream by headward erosion with attendant flow piracy. Downstream the valley lengthens by forced regression.
Gravity flows carry sands to deep basin.
During the rapid fall, focussing of flow into incised valley leads to flow deepening with attendant increase in shear stress. As a result the deposition within the incised valley is better sorted and has enhanced porosity. Growth faults develop along the prograding delta front. They seem to initiate and continue during the rapid fall phase, but may have begun during the previous highstand systems tract. We suspect that this was due to the subsidence profile and the resulting distribution of relative base level.