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Features of deposition - Coggle Diagram
Features of deposition
Bars
What is it?
A bar, which is a ridge of sand, sediment, gravel or shingle which has been deposited by water which runs between two headlands and it grows completely across the mouth of the bay, running parallel to the coast.
key facts
A sandbar is an exposed or submerged ridge of sand, silt or gravel built offshore or across a bay. An offshore bar forms further out to sea. Waves approaching a gently sloping coast deposit sediment due to friction with the seabed
Formation
It is formed when the coast has a gap of water in it , longshore drift moves the sediment along the shore, this will eventually meet with the gap and block off the water, this connects the beaches together forming a lagoon behind it.
examples
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In between St Agnes and Gugh, Isles of Scilly
Beaches
Formation
The Waves entering the bay are constructive waves, they have a strong swash and build up the beach. These high energy environments wash away the finer sand and leave behind the larger pebbles
What is it?
Beaches are deposits of sand and pebbles at the coast. Sandy beaches are mainly found in sheltered bays. Not all beaches are made of sand. Much of the South Coast of England has pebble beaches.
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Examples
Beach at Durdle Door. Located on the Jurassic Coast in Dorset. It is a famous shingle and pebble beach. It features a striking 200 foot tall natural limestone arch
Spits
Formation
A spit forms when longshore drift moves sediment along a coast until the shoreline changes direction. Waves lose energy and deposit sand and shingle out into the open water, building a ridge. Secondary winds bend the tip into a recurved hook, and a salt marsh forms in the calm water behind it.
What is it?
A spit is a long, narrow ridge of sand or shingle that is attached to the mainland at one and and extends out to the sea or across an estuary. It is made of transported sand or pebbles and materials are often smaller at the end due to attrition.
Key facts
A spit is a narrow, long ridge of sand or shingle that is joined to the mainland at one end and extends out into the sea or across an estuary
Examples
Dawlish warren is a rare, double sand spit located at the mouth of the Exe estuary in devon. It extended roughly 2.5 kms northeast from langstone rock toward exmouth, it acts as a natural barrier that keeps the estuary safe from flooding and severe wave action
Sand dunes
Fomration
Sand dunes are formed when onshore waves deposit sand piled up around an obstacle such as rocks or driftwood, forming mounds and ridges.
The wind also contributes to these hills.
What is it?
A sand dune is a mound, hill or ridge formed from sand, usually deposited by the wind.
At beaches, they normally have grass on them..
Key facts
-Usually occur on a wide, flat beach
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Examples
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Merthyr Mawr Nature Reserve, Wales
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Saltburn Beach, Yorkshire
Salt marshes
Formation
The salt marshes at Dawlish Warren formed because a long sand spit blocks rough ocean waves, creating a calm area behind it. In the sheltered water behind the spit, deposits of mud have built up. An extensive saltmarsh had formed as vegetation has started to grow in the emerging muddy islands
What is it?
A salt marsh is a Tidal coastal wetland regularly flooded by salt water and dominated by saltwater tolerant plants that trap and bind sediment to the bottom of the mash bed . A mudflat is a flat, muddy intertidal area formed by fine sediment deposited in sheltered coastal waters and exposed at low tide.
Key facts
It is a carbon sink, Home to many unique species, buffers wave energy leading to shoreline protection, less coastal erosian and storm protection. Works as a filter as it gets rid of extra nutrients before it gets to the shore
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