Beaches are found in many of the world’s coastal regions, as well as along the shores of major rivers and lakes. Beaches are of great economic importance as they are top tourist attractions. There are numerous ways of classifying beaches, one being their classification based on their composition. Sand, boulders, shingle, and shells are the main materials that make up the beaches, resulting in sandy beaches, pebble beaches, boulder beaches, and shell beaches.
Sandy beaches are the most common of all beach types in the world, and they are found in virtually all continents on earth. This type of beach occurs typically on coasts which experience low-energy waves, which deposit the sand to the beach after being transported by ocean currents. Sandy beaches are most susceptible to backwash erosion, with powerful storms and tsunamis having the potential of stripping a beach of its sand. To remedy the erosion of the sand drastic measures have been employed including beach nourishment where sand is sourced from other places and deposited on the beach. These types of beaches are the habitat of more marine creatures than any other and are known for being the incubation sites of sea turtle eggs. An example of a sandy beach is Australia’s Eighty Mile Beach which is the longest sandy beach on earth, with a total length of 140 miles. Cox’s Bazar is home to another expansive sandy beach which stretches for 75 miles, making it the world’s longest unbroken natural sandy beach.
Pebbles are found on virtually all beaches on earth. However, there are a few beaches in the world that are entirely composed of pebbles, which are known as pebble beaches. The pebbles that cover these beaches vary in size, ranging between 0.1 and 7.9 inches in diameter with the larger pebbles often being found nearer to the shore. Pebble beaches are formed after pebbles carried by ocean currents are deposited on the shore by high-energy waves. Pebble beaches are excellent in the prevention of backwash erosion and dissipation of wave energy due to their porous nature. Pebble beaches are picturesque, and since they are not as popular among tourists as sandy beaches, they are less-crowded making them ideal for a private beach experience. Also known as shingle beaches, this type of beaches is popular among rock collectors, who collect the smooth pebbles which are used in exterior and interior decorations of homes. Most of the pebbles found on shingle beaches are made from magnetite, granite, pumice, and flint rocks. Some of the examples of a shingle beaches include Dungeness in England, Alby in Sweden, and Birdling’s Flat in New Zealand among many others.
Boulder beaches are so named due to the boulders that cover their shorelines. The size of the boulders found on boulder beaches ranges from tiny pebbles to huge house-sized boulders. An example of a boulder beach is the Valugan Boulder Beach, which is covered with boulders. Situated in Batanes, Philippines, the beach is one the true boulder beaches in the world, as the shoreline is entirely made up of boulders. The andesite boulders are thought to have been deposited on the beach from the violent volcanic eruption of Mount Iraya in 400CE. Waves from the Pacific that have pounded the boulders for centuries have polished their edges, giving them their characteristic smooth surfaces. New Zealand’s Otago Peninsula has a boulder beach on its Pacific side. The beach which is known as Boulder Beach is covered with boulders of varying sizes.
As the name alludes, a shell beach is almost entirely made up of shells. The shells that cover these beaches are mainly from dead mollusks and are deposited on the shore by waves. In some of the beaches, the shell layer can be dozens of feet in depth. Examples of this type of beaches are quite a few and only two exist that are true shell beaches which are Australia’s Shell Beach and Sanibel Shell Beach of the United States. Shell Beach, Australia is one of the two legitimate shell beaches in the world, as it is purely composed of shells. The beach is situated in Western Australia’s Shark Bay which lies about 28 miles from the town of Denham. Shells cover 37 miles of this beach and are, in some places, 33 feet deep. The shells are from a mollusk known as cockle of the “Fragum erugatum” species. The abundance of shells on Shell Beach is blamed on the marine environment in which the cockle inhabits. The L’Haridon Bight, in which the cockle is endemic, is highly saline making it not conducive to the cockle’s natural predators. Coquina is a type of limestone found in Shell Beach that is formed from the cockle shells. The limestone was once a popular building material in the region. The other legitimate shell beach in the world is Sanibel Island’s beach. The beach which is situated in Florida, US is made up of millions of shells. The high number of shells on the beach is due to the island’s positioning on the Gulf of Mexico, as it has east-west bearing instead of the north-south bearing of the neighboring islands. This special orientation makes the island form a large shovel collecting the shells carried by the ocean currents of the Gulf of Mexico. There exist other shell beaches around the world, which despite not being true shell beaches are nonetheless covered by vast numbers of shells. Gwynedd, Wales is home to one such beach which is situated in Shell Island. Another shell beach is the Anse de Grande Galet Beach which is situated on the island of Saint Barthelemy.
Sea glass is another substance that covers some of the earth’s beaches. Sea glass forms after broken glass disposed of in the sea are acted upon by erosion action, which over time smoothens its sharp edges to result in a piece of glass with smoothened and rounded surface. There are no beaches that are entirely composed of sea glass, due to the small quantities of sea glass that occurs naturally in the earth’s oceans. However, there are a few beaches where large quantities of sea glass cover the surface. Bermuda’s Black Bay Beach is one beach that is covered by sea glass.