Cliff formation from a gently sloping shoreface - MikeWalkden/SCAPE GitHub Wiki

Query:

.. how to model cliff face from a gently sloping plane surface of consolidated sediment at the coastline. Obviously, there is a continuum from near horizontal initial slope to vertical initial slope. SCAPE clearly does well at one end of this continuum, but what about the other end?

SCAPE shows very interesting behaviour at the sub-horizontal end of the spectrum (i.e. a very gently sloping shoreface). This behaviour varies with the:

• slope
• strength of the consolidated material
• sediment content of the consolidated material and
• rate of sea level rise.

Where the slope is gentle, the rate of SLR is high, and the material strength is high, the sea rises up the gently sloping shoreface with SCAPE simulating minimal erosion and minimal release of sediment. This mode is essentially one of simple inundation by the rising sea over low topography.

Where the slope is steeper, the rate of SLR is slower and the material strength is low, SCAPE simulates wave action carving into the shoreface. This creates a distinct cliff and shore platform as in the image below:

Where the slope is steeper, the rate of SLR is slower the material strength is low and the beach-suitable sediment content is high, SCAPE simulates the formation of shore platform and a beach that can become very wide and prevent a cliff from forming as in the figure below:

This behaviour seems similar to the formation of dune fields (perhaps also barrier islands).

The axes in these figures are distorted making the initial shoreface slope look steeper, but they are examples of simulations with an initially shallow slope.