Spits,tombolos,bars and Barrier-beaches Flashcards
What is a spit?
Enlongated, narrow ridge of land.
One end joined to mainland and projects out into the sea or estuary, usually on a drift-aligned coast.
What is a spit composed of?
Composed of sand and or shingle and the mixture is very much dependent upon the availability of material and the wave energy required to move it.
What determines material being carried along the beach?
The prevailing winds and maximum fetch will be carried along the beach by the process of longshore drift.
There is a build up of sand and shingle where?
In more sheltered water in the lee of the headland.
As material begins to move in the given direction, what happens ?
Storms build up more material above the high water mark, giving a greater degree of permanence to the feature.
The finer material is carried where ?
In the direction of prevailing winds into deeper water of the estuary, and as the water loses its capacity to transport it further is deposited, extending the ridge into the estuary.
The end of the spit then begins to do what?
Begins to curve round as wave refraction carries material round into the more sheltered water.
The second most dominant wind does what?
The second most dominant wind direction and fetch may contribute to this, pushing the spit material back towards the mainland.
The spit cannot do what?
Grow all the way across the estuary as the material is carried seaward by the river and the deeper water at the centre inhibits growth.
Characteristics of simple spits?
Are either straight or recurved.
Do not have minor spots, or recurved ridges, along their landward edge.
