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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Coast | 3/4 | https://en.wikipedia.org/wiki/Coast | reference | science, encyclopedia | 2026-05-05T07:34:34.633460+00:00 | kb-cron |
==== Destructive and constructive waves ==== Swash is the shoreward flow after the break, backwash is the water flow back down the beach. The relative strength of flow in the swash and backwash determines what size grains are deposited or eroded. This is dependent on how the wave breaks and the slope of the shore. Depending on the form of the breaking wave, its energy can carry granular material up the beach and deposit it, or erode it by carrying more material down the slope than up it. Steep waves that are close together and break with the surf plunging down onto the shore slope expend much of their energy lifting the sediment. The weak swash does not carry it far up the slope, and the strong backwash carries it further down the slope, where it either settles in deeper water or is carried along the shore by a longshore current induced by an angled approach of the wave-front to the shore. These waves which erode the beach are called destructive waves. Low waves that are further apart and break by spilling, expend more of their energy in the swash which carries particles up the beach, leaving less energy for the backwash to transport them downslope, with a net constrictive influence on the beach.
=== Rivieras ===
Riviera is an Italian word for "shoreline", ultimately derived from Latin ripa ("riverbank"). It came to be applied as a proper name to the coast of the Ligurian Sea, in the form riviera ligure, then shortened to riviera. Historically, the Ligurian Riviera extended from Capo Corvo (Punta Bianca) south of Genoa, north and west into what is now French territory past Monaco and sometimes as far as Marseille. Today, this coast is divided into the Italian Riviera and the French Riviera, although the French use the term "Riviera" to refer to the Italian Riviera and call the French portion the "Côte d'Azur". As a result of the fame of the Ligurian rivieras, the term came into English to refer to any shoreline, especially one that is sunny, topographically diverse and popular with tourists. Such places using the term include the Australian Riviera in Queensland and the Turkish Riviera along the Aegean Sea.
=== Other coastal categories === A cliffed coast or abrasion coast is one where marine action has produced steep declivities known as cliffs. A flat coast is one where the land gradually descends into the sea. A graded shoreline is one where wind and water action has produced a flat and straight coastline. A primary coast isone which is mainly undergoing early stage development by major long-term processes such as tectonism and climate change A secondary coast is one where the primary processes have mostly stabilised, and more localised processes have become prominent. An erosional coast is on average undergoing erosion, while a depositional coast is accumulating material. An active coast is on the edge of a tectonic plate, while a passive coast is usually on a substantial continental shelf or away from a plate edge.
== Landforms == The following articles describe some coastal landforms:
=== Cliff erosion === Much of the sediment deposited along a coast is the result of erosion of a surrounding cliff, or bluff. Sea cliffs retreat landward because of the constant undercutting of slopes by waves. If the slope/cliff being undercut is made of unconsolidated sediment it will erode at a much faster rate than a cliff made of bedrock. A natural arch is formed when a headland is eroded through by waves. Sea caves are made when certain rock beds are more susceptible to erosion than the surrounding rock beds because of different areas of weakness. These areas are eroded at a faster pace creating a hole or crevice that, through time, by means of wave action and erosion, becomes a cave. A stack is formed when a headland is eroded away by wave and wind action or an arch collapses leaving an offshore remnant. A stump is a shortened sea stack that has been eroded away or fallen because of instability. Wave-cut notches are caused by the undercutting of overhanging slopes which leads to increased stress on cliff material and a greater probability that the slope material will fall. The fallen debris accumulates at the bottom of the cliff and is eventually removed by waves. A wave-cut platform forms after erosion and retreat of a sea cliff has been occurring for a long time. Gently sloping wave-cut platforms develop early on in the first stages of cliff retreat. Later, the length of the platform decreases because the waves lose their energy as they break further offshore.
=== Coastal features formed by sediment ===
=== Coastal features formed by another feature === Estuary Lagoon Salt marsh Mangrove forests Kelp forests Coral reefs Oyster reefs
=== Other features on the coast ===
== Coastal waters ==