A beach is a geological landform along
the shoreline of an ocean, sea, lake or river. It
usually consists of loose particles which are often
composed of rock, such as sand, gravel, shingle,
pebbles or cobblestones. The particles comprising
the beach are occasionally biological in origin,
such as mollusc shells or coralline algae.
Wild beaches are beaches which do not have lifeguards
or trappings of modernity nearby, such as resorts
and hotels. They are sometimes called undeclared,
undeveloped or undiscovered beaches. Wild beaches
can be valued for their untouched beauty and preserved
nature. They are most commonly found in less developed
areas including, for example, parts of Puerto Rico,
Thailand, the Philippines, and Indonesia.
Beaches typically occur in areas along the coast
where wave or current action deposits and reworks
Beaches are the result of wave action by which waves
or currents move sand or other loose sediments of
which the beach is made as these particles are held
in suspension. Alternatively, sand may be moved
by saltation (a bouncing movement of large particles).
Beach materials come from erosion of rocks offshore,
as well as from headland erosion and slumping producing
deposits of scree. Some of the whitest sand in the
world, along Florida's Emerald Coast, comes from
the erosion of quartz in the Appalachian Mountains.
A coral reef offshore is a significant source of
The shape of a beach depends on whether or not the
waves are constructive or destructive, and whether
the material is sand or shingle. Constructive waves
move material up the beach while destructive waves
move the material down the beach. On sandy beaches,
the backwash of the waves removes material forming
a gently sloping beach. On shingle beaches the swash
is dissipated because the large particle size allows
percolation, so the backwash is not very powerful,
and the beach remains steep. Cusps and horns form
where incoming waves divide, depositing sand as
horns and scouring out sand to form cusps. This
forms the uneven face on some sand shorelines.