Coasts

• Carbonation Rainfall absorbs atmospheric CO2 to create a weak carbonic acid. This then reacts to the calcium carbonate in chalk/limestone coastlines which produces calcium bicarbonate which is washed away in solution
• Aeolian Processes Wind Processes
• Deflation When wind picks up sand beyond it's entrainment velocity (it drops some sand)
• Another name for rising tide: Flood tide
• What are falling tides also called? Ebb Tides
• Lithology The make up of each rock type
• Structure The way rocks are inclined or geologically arranged
• Differential Erosion Where neighbouring rocks have different rates of erosion
• Salt Crystal Growth Occurs when salt-laden water moves into rock pores. As the water evaporates, the salt crystals left behind grow and create pressure in the rock. Common in arid regions where evaporation is rapid
• Hydration Repeated wetting and drying of rocks affect its minerals in different ways. If the minerals expand and contract at varying rates, pressure increases and the rock disintegrates
• Weathering in Glacial areas Susceptible to frost action but too cold for much chemical weathering
• Weathering in Temperate climates Fluctuating temperature results in both physical and chemical weathering
• Weathering in arid climates Low rainfall and no vegetation means very low weathering rates
• Slumping More permeable rocks absorb water which adds weight to the slope as well as providing lubricant for movement. It can occur very rapidly
• Rockfalls Occur due to the undercutting of rocks by waves
• Pounding When the mass of a breaking wave exerts pressure on rock causing it to weaken
• Thermal Expansion (Insolation weathering) Rocks expand when heated and contract when cooled, if subjected to frequent temperature cycles, outer layers may crack and flake off
• Clastic Sedimentary Rock Rock and mineral fragments e.g sandstone or shale. Formed from the transportation of rock fragments which then get deposited and lithified (compacted and cemented) to form a new rock
• Biochemical Sedimentary Rock Precipitation of remains of living organisms e.g limestone or coal
• Chemical Sedimentary rocks Precipitated from solution as a result of a temperature change e.g rock salt
• Sand Dunes Form when dry material from flat open beaches is blown inland. Dunes migrate and plants colonise and adapt to the new environment
• How are mudflats formed? They're salt marshes formed of finer material which flocculates (sticks together) in the shallow water of estuaries. Plants adapt to salt water and tidal conditions
• Coastal System The coastal system is an open system because rivers input large amounts of sediment as well as terrestrial or marine erosion as inputs. Currents can transport sediment away as well as the backwash of waves
• Drift Aligned Beach When a spit formed by longshore drift spans a bay and joins two headlands. Open system with sediment freely moving through the system
• Swash Aligned Beach Usually a fairly closed system as there is a fairly limited transfer of material to or from the beach
• Ripples Waves move back and forth, sand grains are distributed equally either side of crests
• Ridges and Runnels When swash meets the returning water in the backwash it deflects the water parallel to the shore creating ridges
• Cusps Temporary features formed by collection of waves reaching the same point where swash and backwash have similar strength. Sides of the cusp channel incoming swash into centre of depression producing a strong backwash dragging material down beach from centre of cusp enlarging depression
• Berms Ridge features are formed with swash action at high tides. High berms are usually formed in storms. Mostly found on shingle beaches because aeolian processes erode sandy berms
• Winter Beach High energy condition profiles are gentler. Incline dissipates wave energy. Swash is interrupted by return of backwash so doesn't transport sediment up the beach. Destructive wave action removes sediment further down making a large ridge at top of beach
• Summer Beach Low energy conditions have steep profiles so reflect wave energy back to the sea. If there is a long time between waves, backwash will return before next swash and doesn't interfere with next wave, this is constructive wave action. They have berms at the back
• Onshore Bar Accumulation of sediment parallel and joined to mainland (spit joining 2 headlands) which is often exposed at low tide. Lagoon forms behind bar which often gets filled with more sediment gradually. An example is Loe bar in Cornwall
• Swash aligned onshore bar formation Sand bank develops offshore and pushed onshore by constructive wave action. May have occured as sea level rise progresses
• Tombolos Ridge of sand joining an island to the mainland. Exposed at low tides. In shallow water, wavelength shortens and wave slows down, the wave refracts. Waves lose energy when they turn round a corner. This causes deposition which can create a ridge of sediment. E.g Chesil Beach
• What do horizontal strata mean for the cliff profile? Uniform horizontal strata produce steep cliffs
• What can a steep seaward dip cause for cliffs? Rock slabs slide down the cliff along bedding planes
• What type of cliff profille is it when the rocks dip inland? Stable and steep cliff profile
• What does it mean for the cliff profile when rocks dip gently seawards with near vertical joints cliffs? Joints are opened by weathering and pressure release which can lead to mass movement
• Relative Sea Level The level of the sea in relation to the land with which it meets
• Marine Transgression A rise in relative sea level and the sea flows over the land to cover areas which would have formerly been exposed - coastline retreats