Cuspate Foreland - Movement

Movement

Once formed, cuspate forelands can remain where they are and continue to develop as sediment accumulates, or alternatively they may migrate down the coast as one side of the foreland erodes and the other side accretes. Cuspate Forelands that move are typical of those that are formed on open coastlines. The direction of migration is often indicated by a series of successive beach ridges on the advancing side of the foreland where there is less wave energy. The movement of cuspate forelands is commonly explained by longshore drift acting as the main process. However, there have been observed cases where two cuspate forelands on the same shoreline have migrated in opposite directions, showing that longshore drift does not always provide a sufficient explanation for their migration.

If there is an offshore sandbank present, the position of the cuspate foreland is usually related to its position. If there is a change in the position of the sandbank, the position of the cuspate foreland typically follows. Not only does the sandbank act like an island since it causes waves to refract around it, but it also provides a source of sediment. As sand erodes from the sandbank, it is pushed towards the coastline, contributing to the formation of the cuspate foreland as the sandbank migrates along the coast. This often occurs in the opposite direction to longshore drift.

In the case of a cuspate foreland that has formed close to an island, it is possible for it to extend right up to the island, forming a tombolo. Depending on the physical conditions such as storms, the feature can alternate between a cuspate foreland and a tombolo. Gabo Island in South Australia is an example of where this occurs.

Read more about this topic:  Cuspate Foreland

Famous quotes containing the word movement:

    She had to lean away.
    She dared not stir a foot,
    Lest movement should provoke
    The demon of pursuit
    That slumbers in a brute.
    Robert Frost (1874–1963)

    Every little movement has a meaning all its own.
    Otto Harbach (1873–1963)

    It is certainly safe, in view of the movement to the right of intellectuals and political thinkers, to pronounce the brain death of socialism.
    Norman Tebbit (b. 1931)