Abstract

A recent theoretical model of sediment erosion, transport, and deposition caused by the interacting waves and currents on a continental shelf is used to predict changes in the size distribution of a heterogeneous sediment bed and the formation of micro-stratigraphy during storms. This one-dimensional, vertical model includes the feedback interactions between the structure of the benthic boundary layers, resuspended sediments, density stratification, and the composition of the bed. The oceanographic processes are linked to their geological effects via an armouring model that provides for selective removal of finer sediment and for the movement of coarser material as migrating ripples. The passage of a modeled storm event over the mid-shelf sediments results in the formation of graded strata of the order of 0.5 to 5.0 cm thick, composed of the reworked sands and the successively finer sediments redeposited from suspension. When applied at an array of locations on the Washington continental shelf, the model allows assessment of the relative impact of waves and currents during both frequent and extreme sediment-transporting events. Results from well-posed models such as this provide a new tool for interpreting the patterms of erosion, deposition, and dispersal of sediments in shelf environments.