====== Beach cusp formation ======

//Beach Cusps// are the very well-known shoreline formations which take the form of a repeating, curved 'sawtooth' pattern. They can be composed of various grades of sediment, i.e. sand, pebbles, mud etc..

They can form a large-scale arrays, sometimes stretching for kilometres along a beach. The cusps vary in spacing and size - with regular spacings of a few metres up to 60 or so.

They tend to be quasi-permanent - sometimes growing or retracting - but largely self sustaining. Although storm surges can remove the entire pattern, they usually re-emerge fairly quickly.

Possible ways in which they form and maintain themselves have been debated for many years.

There are two main theories :

• The standing edge wave theory : The idea that the patterns are formed by groups of circular 'edge waves' along the shoreline interacting with incoming waves from the ocean (see [[https://en.wikipedia.org/wiki/Beach_cusps#Standing_edge_wave_theory|Wikipedia]]).

and the :

• Self-organization theory : The idea that feedback processes between currents and sediment can result in patterns which 'self-organize' (see [[https://ui.adsabs.harvard.edu/abs/2000JGR...10521991C/abstract|Journal of Geophysical Research: Oceans,]] Volume 105, Issue C9, pp. 21,991-22,002)

The self-organization theory is currently the most accepted explanation.

Further reading and technical details :[[https://www.mdpi.com/2076-3263/11/4/148/htm|Geosciences 2021, 11(4), 148;]]

----

Also see : [[content:earth_sciences:yardangs]] and [[content:earth_sciences:sand_dunes]]