Step 1: Read the key terms list below. Make sure that you understand and could give a definition to somebody else.
Step 2: Read the information in Section 1. Answer the exam questions here:7.6 – deposition landforms
Spit: A length of new land made of sand or shingle jutting out into the sea from the coastline.
Bar: A spit that has grown across a bay.
Beach: A deposit of sand or shingle, often found in bays.
Section 1: Beaches
Beaches are found where deposition occurs. Sandy beaches are often found in bays.
Waves entering a bay tend to mirror and follow the shape of the coast. This means that the water gets shallower as the waves enter the bay. This is known as wave refraction. This means that wave energy is reduced in bays, resulting in increased deposition.
Pebble beaches may form in areas where cliffs are eroded and where the waves have high energy.
Ridges or Berms are characteristics of a beach. These are small ridges representing different high-tide levels.
A spit is a large, narrow length of land extending into the sea from the land.
As sediment is transported along the coast by longshore drift, it gets deposited where the coastline changes direction or at the mouth of a river.
Over time, as more and more sediment is deposited, the formation extends into the sea. Due to waves approaching in different directions at the tip, a spit often becomes curved.
Eventually the sediment breaks to the surface and new land is formed. This is known as a Spit.
Spits are often home to grass and bushes, along with a wide variety of coastal wildlife. On the sheltered side of the spit, salt marshes and mudflats will form. These create a habitat for coastal wildlife and birds.
Spits are very vulnerable to erosion, especially during storms.
Sometimes, longshore drift may causes a spit to grow across a bay. This creates a freshwater lake or lagoon behind it. This is known as a bar.
When offshore bars are driven onshore by rising sea levels, they form a barrier beach.