Higher Lithosphere

1. I can explain how the sea erodes the landscape by the processes of: 1. Hydraulic Action 2. Abrasion 3. Attrition 4. Solution

<a href="https://www.twigscotland.com/film/coastal-processes-waves-1118/">https://www.twigscotland.com/film/coastal-processes-waves-1118/</a> 2.26 minutes

<a href="https://www.twigscotland.com/film/coastal-processes-1152/">https://www.twigscotland.com/film/coastal-processes-1152/</a> 2.25 minutes

Coastal Processes of Deposition

1. I can explain how the sea shapes the landscape by the processes of: 1. Longshore Drift

Longshore Drift

formation of erosional and depositional features in coastal landscapes: 1. Wave Cut Platform 2. Headland and Bay 3. Cave&nbsp;/ Arch / Stack 4. Spit 5. Bar 6. Tombolo&nbsp;

Spits are low ridges of beach material (1) that partly extend across a bay or river estuary (1). They form where the coastline changes direction and where there is shallow water (1). The level of sand will build up until it is eventually above sea level (1). The spit cannot develop right across the bay as the flow of the river estuary prevents deposition (1) Often a secondary wind (one less prevalent) can cause the spit to form a hooked shape (1) called a recurve or hooked spit.&nbsp; In the sheltered area between the spit and land a salt marsh may form (1). An example is Sandbanks, Poole (1).

Rocks contain weak points that are more easily eroded (1). Over time, lines of weakness are enlarged and develop into small sea caves (1). In some cases, a blowhole can form in the roof of the cave (1) as compressed air is pushed upwards by the power of the waves, causing vertical erosion (1). There may be erosion on both sides of the headland due to wave refraction (1) until eventually the sea cuts through the back walls of the caves,&nbsp;forming an arch (1). Continued erosion&nbsp;enlarges the arch (1).&nbsp;The base of the arch is also undercut by the erosion, causing the arch to become unsupported (1). Eventually the arch collapses to form a stack&nbsp;which is separated from the headland (1). Old Harry is a stack in Dorset (1).&nbsp;

<a href="https://timeforgeography.co.uk/videos_list/coasts/formation-of-a-sea-stack/">https://timeforgeography.co.uk/videos_list/coasts/formation-of-a-sea-stack/</a> 2.11 minutes

Explain the processes and stages involved in the formation of a headland and bay. You may wish to use an annotated diagram or diagrams. 8

Coastal Processes of Deposition

Longshore Drift The swash moves up the beach at an angle (1) due to the direction of the prevailing winds (1). The backwash moves back down the beach at a right angle (1) due to gravity (1).

Tombolo’s are low ridges of beach material (1) that connect the mainland to an island (1). They form where the coastline changes direction (1) and where there is shallow water and an island close by (1). The level of sand will build up until it is eventually above sea level (1). It can be covered during high tide (1) but is possible to walk across to the island during low tides (1). An example is Chesil Beach to Portland (1).

Sand Spit, Sand Bar &amp; Tombolo

Very few coastlines are perfectly straight, and few sea beds have uniform height and shape.&nbsp; As waves approach an uneven coastline, they reach the headlands first, this focuses a lot of energy on those forelands and bends the waves into the bays where the energy expended is less.&nbsp;&nbsp;

<a href="https://timeforgeography.co.uk/videos_list/coasts/formation-of-a-wave-cut-platform/">https://timeforgeography.co.uk/videos_list/coasts/formation-of-a-wave-cut-platform/</a> 2.15 minutes

Headlands and bays form along discordant coastlines (1).&nbsp;This is when alternating bands of rock do not run parallel to the sea (1). Alternating bands of hard and soft rock such as chalk (1) (hard) and clay (soft) are eroded at different rates (1). This is called differential erosion (1). A headland is an area of hard rock which juts out into the sea (1) and a bay is a sheltered area of softer rock between headlands (1). Constructive waves build a small beach in the sheltered bay between the headlands (1). An example of a Headland and bay is Swanage Bay (1)

<a href="https://timeforgeography.co.uk/videos_list/coasts/Large-scale-erosional-landforms/">https://timeforgeography.co.uk/videos_list/coasts/Large-scale-erosional-landforms/</a> 1.16 minutes

Coastal Processes of Erosion

Hydraulic action – force of the waves crashing against the shore and cliffs forces air into cracks in the rock (1), causing the air to implode, the shockwave erodes the rocks (1). Abrasion – wearing away of cliff by sand, shingle and pebbles (1) hurled against them by waves (1). Attrition – waves cause eroded material to smash against each other (1).&nbsp;Gradually the eroded material becomes smaller and rounder aiding abrasion (1). Solution – dissolving of certain rock types (1) by the naturally occurring acid and salt in the sea water (1).

<a href="https://timeforgeography.co.uk/videos_list/coasts/marine-erosion-processes/">https://timeforgeography.co.uk/videos_list/coasts/marine-erosion-processes/</a> 2.30 minutes

Cliffs form where there is harder more resistant rock (1) such as granite / chalk (1). Wave energy is at its greatest when a high, steep wave breaks at the foot of a cliff (1). Continued erosion causes the notch to become larger over time (1) Weaknesses such as joints, faults or cracks in cliffs (1) are undercut by erosion to form a wave-cut notch (1) the rock above overhangs over the notch and, as erosion continues, the notch enlarges (1) until the unsupported overhang collapses due to the weight (1). The new cliff face is then eroded and through time, the cliff retreats inland, leaving a gently-sloping rocky surface called a wave-cut platform (1), which extends out to sea away from the cliff (1). The platform is abraded by rock materials, with rock pools and potholes forming, evident at low tide (1). An example of a cliff is Seacombe Cliff (1).&nbsp;

Bars are low ridges of beach material (1) that fully extend across a bay (1). They form where the coastline changes direction and where there is shallow water (1). The level of sand will build up until it is eventually above sea level (1). In the sheltered area between the bar and land is called a lagoon may form (1). Overtime this may dry up and infill with deposition (1). An example is Chesil Beach &amp; Fleet Lagoon (1).

LITHOSPHERE COASTAL Higher Geography

Explain the processes and stages involved in the formation of a stack. You may wish to use an annotated diagram or diagrams. 10

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