2B.5 Sediment Transport and Deposition

Question 1

2B.5a sediment transportation

Angle of wave attack

Answer 1

sediment transportation is influenced by the angle of the wave attack

Question 2

2B.5a sediment transportation

Longshore drift

Answer 2

As the waves advance at an angle to the coast, beach material is carried up the beach. The backwash then pulls material down the beach at right angles to the shore. The net effect of the movement of sediment is a lateral shift.

Where the removal of sediment is greater than the supply of new sediment, the beach is eroded.

Question 3

2B.5a sediment transportation

Tides and currents

Answer 3

The angle at which waves approach a beach is a major factor in coastal sediment transport. However, tides and currents also affect the process of longshore drift.

Tides are changes in the level of seas and oceans- caused by the gravitational pull of the moon and, to a lesser extent, the sun. The UK coastline experiences two high and low tides a day.

The relative difference in height between high and low tides is called the tidal range. A high tidal range creates relatively powerful tidal current, as tides rise and fall. Tidal current can become particularly strong and fast in estuaries and narrow channels, and are important in transporting sediment.

Question 4

2B.5a sediment transportation

marine transport

Answer 4

traction- relatively large and heavy rocks are rolled along the seabed

saltation- smaller and lighter rocks ‘bounce’ along the seabed

lighter sediment is carried in suspension

dissolved sediment is carried in solution

Question 5

2B.5b transportation and deposition produce distinctive coastal landforms

beaches

Answer 5

a

Question 6

2B.5b transportation and deposition produce distinctive coastal landforms

recurved and double spits

Answer 6

A spit is a long narrow feature, made of sand or shingle, which extends from the land into the sea or estuary in the direction of the coastline.

This is formed by longshore drift occurring where there is a sudden change in direction and sediment will begin to build up across the estuary mouth and a spit will start to form. The end of the spit will also begin to cure around as wave refraction carries material round in to the more sheltered water behind the spit, creating a recurved spit.

The outward flow of the river associated with estuary prevent the spit from extending right across the estuary mouth.

Question 7

2B.5b transportation and deposition produce distinctive coastal landforms

offshore bars

Answer 7

a

Question 8

2B.5b transportation and deposition produce distinctive coastal landforms

barrier beaches and bars

Answer 8

a

Question 9

2B.5b transportation and deposition produce distinctive coastal landforms

tombolos

Answer 9

a

Question 10

2B.5b transportation and deposition produce distinctive coastal landforms

cuspate forelands

Answer 10

a