Edexcel A Level Geography: Coastal Processes Revision Notes PDF

Head to www.savemyexams.com for more awesome resources Edexcel A Level Geography Your notes Coastal Processes Contents Landscapes & Features of The Littoral Zone Influence of Geological Structure Factors Affecting...

Head to www.savemyexams.com for more awesome resources Edexcel A Level Geography Your notes Coastal Processes Contents Landscapes & Features of The Littoral Zone Influence of Geological Structure Factors Affecting Coastal Recession & Stability Page 1 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Landscapes & Features of The Littoral Zone Your notes Littoral Zone The coast as a system As with any geographical system, the coast, as a system, has inputs, stores, transfers and outputs The system constantly strives to be in a state of dynamic equilibrium The coast can be viewed as both an open system and a closed system It is an open system because it receives inputs from the lithosphere, atmosphere, hydrosphere, biosphere and cryosphere However, during research and coastline management the coast can be seen as a closed system where a specific sediment cell is examined Page 2 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Your notes The coast as a system There are examples of positive feedback at the coast As waves erode the cliff, material is released This material abrades the cliff which results in even more cliff erosion There are also examples of negative feedback at the coast As the shore is eroded, the material makes the wave-cut platform wider This can absorb wave energy and reduce the impact at the base of the cliff The littoral zone Page 3 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources The littoral zone is the area of the coast that can be affected by wave action It is a dynamic zone which means that it is constantly changing due to the interaction between Your notes processes on land and in the sea These changes can be: Long-term due to climate or sea level change Short term due to the tides, waves, and storms It is divided into four zones: Backshore is usually beyond the influence of wave action but can be affected during storm events Foreshore is the intertidal area between high and low tide Nearshore is the breaker zone where friction between the seabed and the waves causes them to break Offshore is the area outside the influence of waves The littoral zone Long Term Processes Coastal systems are affected by long term factors which include geology and changes in sea level Geology Page 4 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources The geology is the characteristics of the land which includes both: Rock type Your notes Rock structure Coasts can be classified as: Rocky Sandy Estuarine They can also be classified as: Concordant - where different rock types run parallel to the coast Discordant - where different rock types run at right angles to the coast Sea level change Sea level change can occur as a result of: Global warming - natural and enhanced Tectonic activity - which can lead sections of land to rise or subside Longer-term sea level change can be: Eustatic - when the sea level itself changes Isostatic - when the land rises or falls relative to the sea This leads to coasts that are either emergent or submergent Short Term Processes Coasts can also be categorised by short-term factors: Waves - can be constructive or destructive Tides - tidal range is the difference between high and low tide Rivers Storm events These create coastlines that can be: Retreating or advancing which depends on whether erosion or deposition dominates Page 5 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Dominated by land-based processes (primary coasts) or marine processes (secondary coasts) Large or small tidal range Your notes High or low-energy Characteristics of High and Low Energy Coasts High Energy Coasts Low Energy Coasts Destructive waves Constructive waves Exposed to strong winds and long fetches Sheltered locations with short fetch Higher rates of erosion than deposition Higher rates of deposition than erosion Tend to be rocky coasts Sandy beaches, salt marshes, estuarine and tidal mud flats Steep cliffs - marine cliff profile Gentle relief Less steep cliffs - subaerial cliff profile Sediment from land and sea Headlands, wave-cut platforms Beaches, spits, coastal plains Rocky Coasts Rocky coasts form where there is more resistant geology - in the UK this is mainly in the north and west of the country Cliffs of varying heights and steepness can be found along rocky coastlines: Steep cliffs tend to be found in high energy environments Cliffs with a gentler slope tend to be found in low energy environments Erosion is more dominant than deposition Two types of erosion may dominate along rocky coastlines: Marine erosion - the action of waves Sub-aerial erosion - weathering and mass movement Coastal Plain Landscapes Coastal plains usually occur where the land gradually slopes down towards the sea Tend to be low relief Coastal plains include both: Page 6 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Sandy coastlines Estuarine coastlines Your notes These are usually low energy coastal environments They form due to coastal accretion - when deposition is greater than erosion Sediment for deposition comes from: Offshore sources Terrestrial sources Dunes form, helping to stabilise the coast and reduce erosion Wetlands and marshes form due to poor drainage Estuarine coastlines form at the mouths of rivers and are formed from clay and silt Examiner Tips and Tricks It is important to remember that there are many different ways of classifying coasts and that some of these categories may overlap. For example, rocky coasts are often high energy coastlines. Whereas sandy coasts tend to be low energy. Page 7 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Influence of Geological Structure Your notes Discordant & Concordant Coast Formation Discordant coastlines A discordant coastline is one where the rock structures meet the coast at an angle - run perpendicular to oncoming waves Alternating rock types lead to the formation of headlands and bays Discordant coasts are also known as Atlantic coasts Concordant coastlines Concordant coastlines are where the rock structures run parallel to the coast Dalmatian and Haff coastlines are examples of concordant coastlines Page 8 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Discordant and concordant coastline Your notes Influence of Geology on Coastal Morphology The shape and form of the coastline is known as coastal morphology This is influenced by the rock type (geology) and structure Concordant coastlines - examples Dorset, UK An example of a concordant coastline can be found in the area around Lulworth Cove in Dorset More resistant Portland Limestone runs parallel to the sea with less resistant Purbeck Limestone and Wealden Clay behind it The formation of coves has occurred where the water has broken through at weaker points in the Portland Limestone Page 9 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Your notes Concordant coastline in South Dorset Dalmatian coastline The Dalmatian coast in Croatia is another example of a concordant coastline Formed as a result of tectonic forces and sea level rise Tectonic activity forms anticlines and syncline which run parallel to the sea Sea level rise after the Devensian Glacial then flooded the synclines leaving the anticlines standing above the water The result is a series of islands which run parallel to the coast Page 10 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Your notes Example of a Dalmatian coastline Haff coastline Located along the southern Baltic coastline During the Devensian Glacial large amounts of sand and gravel were deposited offshore After the glacial period had ended the material was then deposited nearer to the land by constructive waves This formed bars across bays and river mouths trapping the water behind to form a lagoon (Haff) These are a feature of low-energy coastlines Page 11 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Your notes Haff coastline on the Baltic coast Discordant coastlines - examples Dorset, UK To the east of Lulworth Cove in Dorset, the coastline runs north to south and so the rocks meet the coast at an angle creating a discordant coastline This leads to the formation of headlands and bays Page 12 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Your notes Headland and bay formation The area is also affected by wave refraction Wave refraction changes the amount of energy reaching the shore on a small local scale Wave energy concentrates at the headland and increases the rate of erosion Page 13 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Your notes Wave refraction around headlands Influence of Geological Structure The geological structure is the way that rocks are folded or tilted - this is known as its lithology Lithology can refer to any of the following characteristics: Strata - layers of rock Bedding planes - horizontal cracks created by pauses in rock formation Joints - vertical cracks caused by tectonic movement or contraction Folds - the result of pressure during tectonic movement causing the rock strata to fold Faults - the result of stress or pressure causing it to fracture Dip - the angle of the rock strata Cliff profiles Cliff profiles are the angle and height of the cliff face A profile also includes any features such as wave cut notches Page 14 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Different lithology creates different cliff profiles Your notes Page 15 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Your notes Page 16 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Your notes Impacts of lithology of cliff profiles Examiner Tips and Tricks You may be asked in the exam to explain the formation of a particular cliff profile. It is essential that you consider the lithology of the cliff face but also the other processes which act upon a cliff including: Hydraulic action and abrasion Subaerial processes Wave type Page 17 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Factors Affecting Coastal Recession & Stability Your notes Coastal Recession Coastal recession is the retreat of the coastline inland, this may be due to: Erosion Sea level rise Submergence Where coastal recession is the result of erosion, this is dependent on the lithology of the coast Mineral composition Rock classification Structure Mineral composition Some minerals are more reactive than others This affects the rate of chemical weathering for example: Calcite is reactive and so easily chemically weathered Quartz is not reactive (inert) so chemical weathering is much slower Rock classification Sedimentary rocks form as a result of compaction and cementation of sediment called lithification Examples of sedimentary rocks include shales, sandstone, and limestone Sedimentary rocks: Erode and weather more rapidly than other types of rock Form in layers Have weak bedding planes They are clastic which means they are made of clasts (sediment particles) Are heavily jointed Often have many bedding planes and fractures Page 18 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Metamorphic rocks form when sedimentary and igneous rocks are altered through heat and pressure, but do not melt in the process Your notes Examples of metamorphic rocks include slate and marble Metamorphic rocks: Have a crystalline structure Are often folded and faulted Are more resistant than sedimentary rock and less resistant than igneous rocks The crystals have a parallel arrangement (foliation) which means they are weaker than igneous rocks Igneous rocks form when molten rock from the Earth's mantle cools and hardens Examples of igneous rocks include granite and basalt Igneous rocks: Erode and weather very slowly Can be categorised into two types: Intrusive igneous rock - forms within the ground, cools slowly, and has large course crystals Extrusive igneous rock - forms on the Earth's surface, and cools quickly, forming smaller crystals Has interlocking crystals Fewer joints and weaknesses than in other rocks Differential Erosion The changing rates of erosion of different rock types is known as differential erosion More resistant rocks erode more slowly than less resistant rocks Differential erosion: Leads to complex cliff profiles Influences rates of recession The differences in geology contribute to landforms generated by processes on the coast On a discordant coastline differential erosion leads to headlands and bays Page 19 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Where there are layers of alternating rock types (strata) this creates a cliff profile where the more resistant rock layers jut out due to the faster erosion of less resistant rock Your notes Permeability can also impact on the rate of erosion: Where permeable rock overlies impermeable rock, the permeable rock is vulnerable to mass movement because the additional weight and lubrication the water creates leads to instability Role of Vegetation Vegetation helps to stabilise coastlines because: The plant roots help to bind the soil/sand together reducing the impact of erosion Wind speeds are reduced by vegetation which decreases erosion and increases deposition Dead plant material adds organic matter to the sand and eventually leads to the formation of soil Vegetation is often sparse in coastal environments because: Exposure to salty/saline water Evaporation of water leads to increased salinity High wind speeds Lack of shade Lack of nutrients Free-draining sediment means water is not retained Pioneer species in the coastal environment are the first plants to grow in the harsh coastal environment, paving the way for other plants that are less able to survive the conditions Pioneer species: Help to stabilise the sediment Add organic matter Increase shade Trap more sediment Sand dune succession Sand dune succession is an example of this process The succession in a sand environment is called a psammosere Sand dunes are a dynamic environment Page 20 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Sandy beaches usually have sand dunes at their rear, because of strong onshore winds transporting dried, exposed sand Your notes Sand grains are trapped and deposited against any obstacle (rubbish, rocks, driftwood etc) and begin to form embryo dunes Dune ridges move inland due to onshore winds pushing the seaward side to the leeward side It is the interaction of winds and vegetation that helps form sand dunes Formation of a sand dune Windblown sand is deposited against an obstruction: Pebbles or driftwood As more sand particles are caught, the dunes grow in size, forming rows at right angles to the prevailing wind Over time, the ridges of the dunes will be colonized and fixed by vegetation in a process called succession The first plants (pioneer species) have to deal with: Salinity Lack of moisture as sand drains quickly (highly permeable) Wind Temporary submergence by wind-blown sand Rising sea levels Coastal Dune Succession Embryo dunes Page 21 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Wind-blown dried sand is trapped by debris and deposition begins Pioneer species such as lyme grass and sea couch grass begin to colonise, these are halophytic Your notes plants which can tolerate high salt levels There is little soil content and high pH levels (alkaline) Embryo dunes are very fragile and reach a maximum height of 1 metre Fore dunes The embryo dunes bring some protection against the prevailing wind This allows other species of plant to grow such as marram grass Marram grass begins to stabilise the dune with its root system which can grow to 3m to reach the water table These plants add organic matter to the dunes making the dunes more hospitable for plants that later grow A microclimate forms in the dune slack Maximum height is 5 metres Yellow dunes These are initially yellow but darken as organic material adds humus to the soil Marram grass still dominates the vegetation, but more delicate flowering plants and insects are found in the dune slacks 20% of the dune is exposed, down from 80% Height does not exceed 8 metres Grey dunes Grey dunes are more stable, with less than 10% of exposed sand and have a good range of biodiversity Soil acidity and water content increase as more humus is added Shrubs and bushes such as gorse begin to appear Height is between 8 - 10 metres Mature dunes As the name suggests, these are the oldest and most stable of the dunes They are found several hundred metres or more from the shoreline Page 22 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources The soil can support a variety of flora and fauna such as oak trees and alders (climax vegetation) This is the final stage in succession which is known as the climax community stage Your notes Salt marsh succession A succession in salty water is called a halosere The plants which are adapted to these conditions are called halophytic plants Salt marshes often develop in estuarine areas because of: A steady supply of sediment from the river Shelter from strong waves In the estuarine environment fresh water and seawater mix This causes flocculation where clay particles stick together The clay particles sink causing sediment to build up The deposited sediment is colonised by algae which: Binds the sediment together Increases organic matter Traps more sediment The sediment builds up and is covered by the tide for less and less time This allows other plants such as cord grass to colonise The height of the sediment increases and is only covered by the highest tides More plants colonise such as sea lavender and sea thrift Saline levels decrease and other plants colonise This continues until a climax community is achieved Examiner Tips and Tricks It is not sufficient to know that vegetation stabilises coastal environments through the action of the roots binding the soil and trapping more sediment. You need to understand the step by step process of succession in a halosere and a psammosere. This will allow you to outline the different Page 23 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources species which colonise the areas at particular stages and explain how the stabilisation of the coastal environment is a gradual process. Your notes Page 24 of 24 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers