Beach cusps

<p>Beach cusps are shoreline formations made up of various grades of <a href="/facts/Sediment/zsIH1A6U">sediment</a> in an arc pattern. The horns are made up of coarser material and the <a href="/facts/Embayment/Cd7dbTc1">embayment</a> contains finer sediment. 
</p><p>They can be found all over the world and are most noticeable on shorelines with coarser sediment such as <a href="/facts/Pebble/spJuLIfI">pebble</a> beaches. However, they can occur with sediment of any size. They  nearly always occur in a regular pattern with cusps of equal size and spacing appearing along stretches of the shoreline. These cusps are most often a few metres long. However, they may reach 60 m (200 ft) across. Although the origin of beach cusps has yet to be proven, once cusps have been created they are a self-sustaining formation. This is because when an oncoming wave hits the horn of a beach cusp, it is split and forced into two directions. The crashing of the wave into the cusps slows its velocity,  causing coarser sediment to fall out of suspension and be deposited on the horns. The waves then flow along the embayments (picking up finer sediment) and run into one another in the middle. After this collision these waves attempt to flow back out to sea where they are met by incoming waves. Therefore, once the cusp is established, coarser sediment is constantly being deposited on the horn and finer sediment is being eroded away from the embayments. This process causes the horners and embayments to at least maintain their size, if not grow larger.
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Beach cusps open-in-new

Beach cusps