landforms of coastal deposition

Question 1

Where are beaches found?

Answer 1

Beaches are found at the point where the land meets the sea and represent the accumulation of sediment deposited between low spring tides and the highest point reached by storm waves

Question 2

What are beaches made from?

Answer 2

they are mainly composed of sand and shingle.

Question 3

Why does sand create beaches with a gentle gradient?

Answer 3

Because of its small particle size which means the sand becomes compact when wet and allows very little percolation. Most of the swash returns as backwash, little energy is lost to friction and material is carried down the beach

Question 4

Why does shingle create beaches with a steep gradient?

Answer 4

Because water rapidly percolates through shingle, so the backwash is limited int he material it can transport down the beach

Question 5

What is a spit?

Answer 5

A spit is an elongated, narrow ridge of land that has one end joined to the mainland and projects out to the sea or across an estuary, usually on a drift aligned coast

Question 6

What is a spit made from?

Answer 6

It is composed of sand and/or shingle and the mixture is dependent upon the availability of material and the wave energy required to move it

Question 7

How is a spit formed?

Answer 7

1) when longshore drift causes the beach to
extend out to sea, usually due to a change in direction of the coastline .
2) This sediment projection can create a salt marsh due to the sheltered, saline environment where water flow speed is lower, allowing deposition of finer sediments to occur.
3) A change in wind direction or wave direction can
cause the end of the spit to curve (known as a recurved end). Over time, the spit may be left with
multiple recurved tips, which is known as a compound spit.
4) In some areas a double spit may
occur where the spits from opposite sides of a bay reach out towards each other, though are
unlikely to touch unless there are no changes to environmental conditions. This could lead to a
barrier beach being formed.

Question 8

What is a barrier beach?

Answer 8

an elongated bank of deposited sand or shingle lying parallel to the coastline and not submerged by incoming tides

Question 9

How is a barrier beach formed?

Answer 9

A barrier beach occurs when a beach or spit extends across a bay to join two headlands . This
traps water behind it leading to the formation of a brackish lagoon which is separated from the sea.

Some barrier beaches may have formed due to
rising sea levels after the last glacial period , when meltwater from glaciers deposited sediment
in the coastal zone. If a barrier beach becomes separated from the mainland, it becomes a
barrier island

Question 10

Where do you find a barrier beach?

Answer 10

They are common in areas with low tidal ranges and can be very large

Question 11

What is a tombolo?

Answer 11

A tombolo is a bar or beach that connects the mainland to an offshore island

Question 12

How is a tombolo formed?

Answer 12

A tombolo is formed due to wave refraction off the coastal island reducing wave velocity , leading to deposition of sediments. They may be covered at high tide if they are low lying

Question 13

Where do you find a tombolo?

Answer 13

They are common in areas with low tidal ranges

Question 14

What is an offshore bar?

Answer 14

An offshore region where sand is deposited

Question 15

How is an offshore bar formed?

Answer 15

They can be formed when the wave breaks early, instantly depositing its
sediment as a loose-sediment offshore bar. Waves may pick up sediment from an offshore bar,
which then provides an important sediment input into the coastal zone . They may also be
formed as a result of backwash from destructive waves removing sediment from a beac h.
Offshore bars may absorb wave energy, reducing erosion in some areas.

Question 16

Sand dunes and vegetation succession

Answer 16

The first colonising plants are called pioneer species, which have special adaptions to help them survive in hostile conditions. Plants such as sea rocket and couch grass are able to cope with the very dry salty and exposed conditions s. When they die, the plants add important organic matter to the developing soil

As the pioneer plants take hold, they help to bind the sand and form low sand dunes called fore dunes. Marram grass is a typical species found in this zone. It is extremely well adapted with long tap roots to seek water. The growth of marram grass is stimulated by burial and its tangle of lateral roots is perfect for binding sand

As the environment changes over time, different species colonise the sand dunes until they become stable. The final community is known as the climactic climax community 999999999999999

Question 17

How are swash aligned beaches formed?

Answer 17

Swash aligned beavers tend to form in low energy environments such as bays that are affected by waves arriving roughly parallel to the shore. The bayhead beach may consist of either sand or shingle, and the power of the waves. High-energy waves will transport sand leaving behind coarser shingle whereas low energy waves will deposit sand or mud

Question 18

How are drift aligned beach?

Answer 18

Drift aligned beaches form where the waves approach the coast at an angle. Longshore drift (a transfer process) moves sediment along the beach, often culminating in the formation of a spit, essentially a sediment sink or store. Sediment may be graded along a drift aligned beach. Finer shingle particles are likely to be carried further by longshore driftand also to become increasingly rounded as they move