Changing coastal landscapes

• Hydraulic action is the force of waves compressing water and air into cracks in the rock widening them
• Abrasion is when waves hurl rocks at the cliff face wearing it down, known as the 'sandpaper effect'
• Solution is when minerals like calcium carbonate, the main chemical of chalk. being slowly dissolved by sea water
• Attrition is when large angular rocks are smashed together by waves which turns them into smaller rounded pebbles and overtime makes sand
• Biological weathering is when vegetation growing on top of the cliff pushes apart the rock with its roots
• Chemical weathering is when chemicals in the rain water dissolves the rock
• Physical / mechanical weathering is the force of wind, rain and waves hitting the cliff and pushes apart the cracks
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  Outputs in the coastal system is when material is removed from, the system and enters another such as depositional and erosional landforms like spits
• Stores in the coastal system is where material is stored such as sediment
• Transfers in the coastal system is how material is moved along a coastline such as longshore drift
• The inter-tidal zone is then most temporally and spatially variable zone of all marine habitats. It holds a variety of plant and animal communities
• Backshore is the land of the inter-tidal zone which is usually above the influence of waves
• Foreshore is the part of the coast between high-water and low-water marks where the area is sometimes covered in water
• Nearshore is sometimes called the breaker zone as it is where the waves break
• Offshore is further out to see and is beyond the influence of the waves
• Prevailing winds from the South-west cause waves to entre the beach at a 45* angle. The waves pick up material, this is known as swash. Gravity pulls waves back to shore at a 90* angle with the material, this is known as backwash. Material is transported across the coastline through the process of longshore drift.
• A luna day is 24 hours and 50 minuets long
• A diurnal tide has one high and low tide per luna day. The high tide occurs at 12 hours and 25 minuets and low tide occurs at 24 hours and 50 minuets. They have a lower tidal range and an example is the Mediterranean coastline
• A semi-diurnal tide has 2 high and low tides per luna day. High and low tides occur every 6 hours and 12.5 minuets. They have a high tidal range and an example in the UK coastline
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  Low energy constructive waves that occur during spring and summer months have a strong swash. This causes deposition to occur which forms steep sloping beaches
• High energy destructive waves that occur during autumn and winter months have a strong backwash. This causes erosion to occur which forms gentle sloping beaches
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  Bands of alternating rock types with differencing resistance to erosion. Hydraulic action and abrasion erodes less resistant rock, like clay, and forms a bay. Attrition creates sand and is deposited to form a beach. More resistant rock like chalk and sandstone erodes slower which forms a headland. Example: Whitmore bay in Barry
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  Hydraulic action causes cracks to widen in the cliff and overtime forms a cave. Abrasion wears down the cave wall until it breaches to from an arch. Gravity causes the arch to collapse and form a stack. Solution undercuts the stack leading it to collapse and form a stump which is only visable at low tide. Example: Old Harry rocks
• South-westerly winds move waves onto the beach at a 45* angle, which is known as swash. Material is picked up from the beach and gravity brings the wave back to sea at a 90* angel, which is known as backwash. This is known as longshore drift which transports material along the coastline. A change in wind direction causes the sediment to be deposited which forms a spit. If deposition continues a tombolo can be formed which is a spit that connects two piece of land. Example: Big-bury on sea in Devon
• Flocculation is when fresh river water enters the coastline and mixes with the salt water. This causes clay particles to coagulate to form flocs, which are heavier than water and are likely to be deposited, commonly behind spits to form salt marshes
• Wave orientation is the direction a wave travels, which can effect it's fetch.
• Wave refraction is the change in direction of a wave due to an irregular coastline. Waves approach parallel to the coastline but they distort energy on headlands and disapates any bays
• Wave reflection is when a wave hits a vertical surface, like a sea wall, and bounces back without loosing energy
• Lithological factors effecting a coastline:

  Hardness- Due to heat and compression igneous rocks, like granite, are harder and more resistant to erosion

  Chemical composition- Depending on the chemical make up of rocks

  Permeability- As water seeps into the surface of rocks, it increases it's resistance to subaerial processes

  Structure of the coastline- The way rocks are geologically arranged change the way they erode
• A concordant coastline, also known as a Dalmatian coastline, have differing bands of rock run parallel to the coast and forms coves
• A discordant coastline, also known as an Atlantic coastline, have differing bands of rock in a crenellated pattern and forms headlands and bays
• Freeze-thaw is when repeated freezing and thawing of water results in the expansion of rocks
• Salt crystallisation is when sea water evaporates from cracks which allows crystals to grow and exerts pressure
• Wetting and drying is constant wetting and drying of clay rich rock to expand and contracts which results in cracks
• Mudslide is when saturated soil made from unconsolidated material flows downhill due to high percipitation
• Slumping is vertically layered soil slumps in a step-wise patternalong a curved surface
• Landsides are when rocks are effected by physical weathering or marine erosion collapse downwards creating a fan of debris at the base of the cliff
• Rock fall is when rocks located in a horizontal layers breakdown and fall to collect as scree at the base of the cliff
• When wind reaches a critical velocity, it transports sediment particles, which can lead to the formation of sand dunes
• Tidal flats are level muddy areas bordering an estuary. They are low energy and are formed deposition of fine sediment. Example- Morecambe Bay in Lanchashire