Four Sources of Beach Material

Four Sources of Beach Material Most beaches of composed of rock breakdown with varying proportions of

biological material usually shell fragments. However if its an

accumulation of material at the high tide mark the following may be

included;

1) Canada-timber beach 2) USA-tin can beach A beach may be a store in

a bay or a mobile stream along the coast.

Four Sources of Beach Material;

· 1) Material eroded from headlands dependant on the rock type. Easily

eroded bolder clay resistant to erosion is granite.

* 2) Sediment moved up onto the beach from the offshore zone

material is washed up from the seabed.

* 3) Large rivers carrying material from inland to the sea mainly

silt and clay.

* 4) Material cycled from one beach along the coast to another.

Beach Materials -

· 1) Sand material 2mm.

* 2) Pebbles 4mm-64mm.

* 3) Unusual to have much 2mm-4mm.

* 4) Unusual to find a mixture of sand and pebbles.

Sand Beaches -

Usually have a gentle gradient and a small particle compact when wet

restricted. The courser the sediment the steeper the beach. Exposed

beaches are gentle and sheltered beaches are steep. They have a strong

swash therefore pushing material up the beach and they have a weak

backwash so less material is carried down the beach.

· Beach Face - is the sharp break of slope that the zone affected by

the high tide wave action.

* Berm - is a horizontal gently inclined area at the top of the

beach which experiences frequent wave action.

* Summer profile of a sand beach is usually hi...

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4) Slope Over Wall Cliffs

· A slope is formed in periglacial conditions i.e. if a cold climate

occurs there will be a lower sea level subject to mass wasting.

· Sea level rose. Erosion at the base of a cliff, which first removed

debris, then commenced erosion forming the vertical cliff (wall) E.g.

Devon and Cornwall.

5) Rock Lithology and Structure -

Strong control over the profile and plan of the cliff. Profile -

controlled by the angle of the bedding plain. Plan - is due to the

general tectonic trend. If the faults are at 90 degrees this equals

headlands and bays - Atlantic Coastline. But if the faults are running

parallel to the elongated coast this equals a Dalmatian coastline.

Resistant rock = slow erosion. Soft and less resistant = faster

erosion. Many faults = friable. No faults = massive.