Delta and shelf clinoform development, the effect of sea level and sediment supply on geometry and time scales; an analogue flume model.

Abstract

Recent years have experienced a bloom in 2D analogue flume modeling, due to the clear and simplified representation it gives on sedimentary systems. The difference in spatial and temporal scales between delta and shelf clinoforms has often been disregarded in those experiments. Furtermore, both the shelf and the delta topsets have been approached as a static entity, rather than a dynamic transit system. Longitudinal profiles from both experimental and real world data sets show however, that characteristic slopes fluctuate with time. A set of simple experiments was conducted in a 2D flume, at the Eurotank Flume Laboratory, at Utrecht University. The experiments allow detailed observation of clinoform response to allogenic forcing, i.e. changes in sediment supply and base level. Changes applied with different frequencies indicate that the spatial scale of the system, dictates its sensitivity to changes applied at the time scales. Secondly, the system was able to change the gradient of the alluvial system with sea level change as sole driving mechanism. Changes observed in topset slope caused by sea level change are approximately 3 times larger than the changes produced by sediment supply. Comparison of the presented flume data, show that it is in agreement with data from large scale Quaternary alluvial systems.