A spit is an area of sand or shingle that has been transported by longshore drift and then deposited as the coastline has changed direction.
It is attached to the land at one end.
It is a depositional landform.
Hurst Castle Spit in Hampshire is a very famous example.
Longshore drift transports material along the coast Transport and deposition occurs in roughly the same direction to form a SPIT, ignoring the change in direction of the coastline The curved end represents periods of change in the direction of longshore drift, as winds have changed direction Sediment (mud or silt) is transported down the river and deposited in the calm waters behind the spit Fresh water marsh is formed here as the build up of sediment is so great that it rises above the water level even in high tide storm conditions. Sometimes this is drained and used for farm land Some of the sediment forms mudflats which are low lying and covered with sea water every high tide. Sometimes the build up of sediment is such that it is only occasionally covered in sea (salt) water. This forms boggy areas of salt marsh
The first sediment in the early stages of spit formation forms mudflats
In time this becomes salt marsh
After a very long period of time it will turn to fresh water marsh
Occasionally strong winds blow from a different direction. Some material is then pushed inland causing the end of the spit to curve. This can happen on a number of occasions over time, producing a spit with several hooked ends.
A spit may grow out across a river estuary. Where the spit is crossing a river mouth, the river will be diverted so that it follows the coastline for some miles before reaching the sea.
A bar is a barrier of sand or shingle that stretches right the way across a sheltered bay, joining to the land at both ends. Bars can form in two main ways:
(a) a spit grows the whole way across a bay
(b) a sandbank develops offshore, parallel to the shore, and is moved towards the coastline by the waves and wind until it joins the mainland
A tombolo is formed where a spit joins an island to the mainland. An example is the Isle of Portland which is joined to the mainland by a shingle ridge known as Chesil Beach.
Slapton Sands (Devon) is an example of a bar. The lagoon of water than has formed on the landward side of the bar is called Slapton Ley.