Initial Morphologic and Stratigraphic Delta Evolution Related to Buoyant River Plumes

This paper presents the results of a numerical model study on initial delta formation in basins of different water depths. A process-based model (Delft3D-Online) is used to calculate fluid flow and sediment transport patterns at a newly formed river effluent. In absence of wave and tidal forcing, the river effluent is fully river dominated. The model results are interpreted in terms of morphology and stratigraphy. For the shallow basin case, the delta develops as a complex, pattern of channels and shoals analogous to Wax delta. The simulated delta development in the deep basin is markedly different and resembles a classic prograding bird foot delta morphology. Typical clay-rich prodelta deposits underlie sandy bar and channel deposits. The top of the sedimentary sequence consists of a clay-rich delta plain deposit. The potential of the process-based model to simulate typical delta morphologies and a realistic stratigraphy provides many new opportunities to bridge typical engineering and geological research approaches.