landforms

Psammosere

The characteristic plant succession that develops on a new sand day ecosystem and achieves or is on the way to achieving a climax community

Xerophytes

A species of plant that is adapted to live in dry conditions

Flocculation

The process in an estuary where rive water mixes with seawater and neutralises tha charges on clay particles meaning they are no longer repellent and may stick together and settle out to help build up the muddy shore on an estuary

Halophytes

Salt tolerant plants eg cord grass, mangroves

What do the characteristics of landscapes depend on

Whether it is a high or low energy coastline, dominated by erosion or depositó a nd if it is more or less intensely managed by people

Example of headlands and a bay in the UK

Lulworth cove, Dorset on a concordant coastline, swanage bay, Dorset on a discordant coastline

Example of a s headland and bay outside of the UK

San Francisco bay, california

How are headlands and bays formed

Erosional processes predominate in areas of less resistant rock forming bays and leaving more resistant rock protruding as headlands which then receive highest energy waves due to refraction so are more vulnerable to erosion than the bays which experience low energy waves that allow sediment to accumulate and form beaches

When considering landforms as results of systems operating at the coast, what are the main inputs

Geology and lithology of coast, angle of the dip in the coastline in front of the headland, the nature of the waves approaching the coast, direction and strength of the prevailing wind

When considering landforms as results of systems operating at the coast, what are the components/ processes

Differential rates of erosion of rocks, wave refraction, erosion of headland, deposition in bay

When considering landforms as results of systems operating at the coast, what are the outputs

Characteristic features of resulting landscape eg headland and bay

What is an example of a cliff and wave cut platform in the UK

Flamborough head, holderness coast, uk

What is an example of cliffs and wave cut platforms outside of the UK

Paracas cliffs in Peru

How are wave cult platforms formed

High and steep waves break at the foot of a cliff where their energy and erosive action is concentrated into a small area of the rock face creating an undercut and forming a wave cut notch, further erosion occurs and over time cliff collapses and line will begin to retreat forming a wave cut platform

What happens as a wave cut platform grows

Waves are forced to break further out to sea so have to travel across more platform before reaching the actual cliff leading to greater dissipation of wave energy, reducing the rate of erosion on the cliff and slowing down the rate of growht on the platform

What is the largest a wave cut platform can grown

0.5km → growth beyond this is unusual

Where do steep cliffs form

Where rock is strong and resistant to erosion such as igneous and metamorphic rocks

What cliffs do sedimentary rocks create

Tend to produce steep and dramatic cliffs if they dip steeply or vertically

Other than rock type what forms steep cliffs

Absence of beach and exposed orientation with a long fetch and high energy waves

What rocks form gentle cliffs

Weak or unconsilidated rocks that are prone to slumping, rocks that dip towards the sea

What other factors lead to gentle cliffs

A wide beach to absorb wave energy

What factors determine the rate of retreat of the cliffs

The balance between marine factors such as wave energy, fetch, presence of a beach and terrestrial factos such as sub aerial processes, rock strength and geology

How does rock type influence rate of cliff retreat

Most rapidly retreating cliffs tend to be composed of very weak rock such as glacial till cliffs at the holderness coast

Where are geos, caves , blowholes, arches, stacks and stumps found in the UK

Dorset

Where are geos, caves , blowholes, arches, stacks and stumps found beyond the UK

Australia

Geo

A steep sided inlet formed when a joint that gets widened by the sea

How are geos formed

Weaknesses such as joints and faults are eroded more rapidly by wave action than the resistant rock surrounding them, hydraulic action is particularly important in forcing air and water into the joints and weakening the rock strata, leads to horizontal collapse of rocks forming steep sided, narrow inlets

What is an example of a geo

Huntsman’s leap in Pembrokeshire which is 35 deep and eroded along a large joint in the Carboniferous limestone

When do blowholes form

When goes form as tunnel like caves which run at right angles to the cliff line enlarge and eventually collapse a blowhole is formed

Example of a blowholes

Trevone, Cornwall

Where do landforms of deposition occur

On coastlines where sand and shingle accumulate faster than they are removed where waves are low energy or where rapid erosion provides and abundant supply of material

Example of a beach in the UK

Brighton/ Newquay beach

Example of beaches outside of the UK

Trafalgar beach ,Cadiz, Spain

Where do beaches form

At the point where the land meets the sea, repsreneting the accumulation of sediment deposited between low spring tides and the highest pint reached by storm waves

What type of beach does sand tend to produce and why

A beach with a more sloping gradient → small particle size menas the sand becomes compact when wet and lows very little percolation meaning most swash returns as backwash, little energy is lost to friction and material is carried down the beach

What is formed at the low water mark of sandy beaches

Ridges and runnels which run parallel to the shoreline and are broken by channels that drain the wtaer off the beach

What does shingle make up

The whole or just upper parts of beaches → larger size means gradient is generally steeper eg chesil beach

Why does shingle make a steeper beach

Water rapidly percolated through shingle so the backwash is somewhat limited in its abiliyt to transport material back down the beach meaning very little erosion occurs

Where and why is a storm beach formed

At the back of the beach when strong swash at high tide level despots the largest boulders above the high tide mark

What forms below a storm beach and why

A series of ridges marking the successively low high tides as the cycle goes form spring to neap tide

What are the ridges known as and what wave creates them

Know as berms built up by constructive waves

Cusps

Semi circular shaped depressions a which form when waves break directly onto the beach and swash and backwash are strong

Where do cusps form

At the junction of shingle and sandy beaches

Where do ripples form

Below cusps by wave actio and Tidal currents

Swash alligned beaches

Orientated parallels to the incoming wave crests, experience minimal longshore drift, can be found on irregular coastline where longshore drift is impede and waves hit sections of the coast head on

Drift alligned beaches

Are generally orientated parallel to the direction of dominant longshore drift, can have considerable amounts of sediment transported long distances along them, initially, develop where a section of coastline is fairly regular or where the predominant wave direction is at an angle to the beach, can extend out from the coastline if there is a suffer change in the direction of the coastline eg an estuary

Why is dynamic equilibrium more important for drift alligned beaches

Without a continuous supply of sediment longshore drift would remove sediment faster than is was deposited

Where is an example f a spit in the UK

East head spit West Wittering

Where is an example of a spit outside of the UK

Sandy hook, New Jersey

Spit

Is an elongated narrow ridge o gland that has one end joined to the mainland and protects out into the sea or across an estuary usually on a drift alligned coast

How is a spit formed

Where the coastline changes to a more north south orientation they’re is a build up of sand and shingle transported by longshore drift in the more sheltered water in the Lee of the headland, finer sediment is carried into the deeper wtaer of the estuary and as the water loses its capacity to transport it is deposited, the ends start to curve round as wave refraction carries matieral round into more sheltere water

Why can’t a spit grow all the way across an estuary

The matieral carried is Seaward by the river and the deeper water at the centre of the estuary inhibits growth

What are the two types of spit

Simple and compound

Simple spits

Area straight or recurved, don’t have minor spits or recurved edges along their landward edge, example is spurns head

Compound spits

May have similar features to sople spits, may have recurved edges or minor spits on their landward sides possible indicating the position where they have terminated in the past

When do sand dunes form

When a spit matures and sand dries out it is blown landward side where it can accumulate and become stabilised by vegetation such as marram grass

Examples of tómbola in the UK

Chesil beach, UK

Example of tombolo outside of the UK

Angle Road of Shodo Island, japan

Tombolo

A spit that joins an island to the mainland that may be covered at high tide and forms hen deposition occurs when waves lose energy

Bars

When a spit develops across a bay when they’re is no strong flow of water form the landward side

Offshore bar

A submerged or partially submerged ridge of sand or coarse sediment that is created by waves offshore form the coast

What type of waves from offshore bars and why

Destructive → erode sand form beach and deposit it offshore

What do offshore bars act as

Sediment sinks and stores

Barrier beach/ island

An elongated bank of deposited sand of shingle lying parallel to the coastline and not submerged by incoming tides or where a beach of spit extends across a bay to join two headland s

What do barrer beaches trap behind them

Lagoons eg slapton ley

When do barrier islands form

Where the bank is high enough to allow sand dunes to develop, where a beach becomes separated from the mainland

Example of sand dunes in the UK

Saunton sands, Devon

Example of spit outside of UK

Bolonia, Spain

Sand dunes

Accumulations of sand shaped into mounds by the wind

What is needed for the formation of sand dunes

Plentiful supply of sand to be washed onshore by contrastive waves, strong onshore winds to blow dried sand to the back of the beach, large tidal rangge to create a large exposure of sand that can dry out at low ride, vegetation growth

Steps to form a sand dune

Sand gets trapped by obstacles t the back of the beach, first dunes to develop are embryo dunes which are suitable for colonisation by grasses, grow upwards and height raises above the reach of all bu highest storm tides creating foredunes which contain little organic matter and can reach height os 20m, dunes gradually boom fires ad dune slacks can form

Embryo dunes

Suitable for colonisation by grassses which stabilise the sand, creating hummocky dunes, marram grass roots bind sand together and adds organic matter ans well as aiding water retention → are pioneer species which have adaptions to hep survive in extreme environments

What happens to foredunes as they increase in organic matter

Become more fixed and greyer in colour

Dune slacks

Depressions within dunes where the water table is on or near the surface and conditions are damp

Wasting dunes

Areas behind yellow and grey dunes where sand supply is gradually it off giving smaller dune features