Coasts 1.1

• What is a system in terms of the coastal landscape as systems - A set of interrelated objects comprising of components and processes that are connected together to form a working unity, coastal landscapes store, transfer energy on varying timescales
• Describe how coasts can be viewed as an open system in terms of the coastal landscape as systems - An open system transfers both matter and energy that can cross boundary to the surrounding environment, with inputs, outputs and throughputs
• Describe the energy and sediment inputs in terms of the coastal landscape as open systems - Energy - wind, waves, tides, currents, suns energy - Sediment - offshore, fluvial, geological
• Describe erosional and depositional stores in terms of the coastal landscape as open systems - erosional - headlands, bays, wave cut platforms, caves carch, geos and blowholes - depositional - beaches, spits, bars, tombolos, salt marshes and dunes
• Describe outputs in terms of the coastal landscape as open systems - Sediment removed by evaporation
• Describe Feedback in terms of the coastal landscape as systems (3) - Dynamic equilibrium results in negative feedback to restore equilibrium - Negative feedback operates to reduce the original change, for example erosion of sand dunes could create a depositional landform, like a bar, reducing energy of the waves allowowing the dunes to recover - Positive feedback, when the change produced operates to increase the original change
• Describe sediment cells in terms of the coastal landscape as systems (2) - Boundaries affected by the topography of the coastline and presence of rivers, large physical features act as natural barriers that prevent the transfer of sediment to adjacent cells - Sediment and sediment sub cells are used to manage coasts more effectively, flamborough head is sediment cell 2A
• Describe sediment budget in terms of the coastal landscape as systems - The balance of the sediment entering and exiting the particular section of the coast, surplus is when inputs are higher than outputs, deficit is vice versa
• What are the various sources of coastal sediment (4) - Terretrial - Mass movement - Fluvial - Aeolian
• Describe weathering as a source of sediment (3) - Physical/mechanical weathering - Chemical weathering - Biological weathering
• Describe the types of physical weathering in terms of physical weathering as a source of sediment (4) - Pressure release - Salt crystillisation - Thermal expansion - Freezethaw
• Describe pressure release in terms of physical weathering as a source of sediment - Pressure release occurs after a buried rock swells upwards after being release causing fractures parallel to the cliff surface
• Describe Salt crystillisation in terms of physical weathering as a source of sediment (2) - Slightly saline water enters pore spaces, evaporation leaves salt crystals which exters stresses on the rock leading to granular disntegration - Sodium sulphate and sodium carbonate expand 300% in temperatures ranging from 26 to 28 degrees
• Describe the forms of chemical weathering in terms of chemical weathering as a source of sediment (5) - Oxidation - iron rich mineral in rock react with o2 in air or fluids - Solution - some salts are soluble in water, or acidic water - Carbonation - Rainwater forms weak carbonic acid reacting with calcium carbonate to produce calcium bicarbonate which is is soluble - Hydrolysis - chemical reaction between rock minerals and water - silicates combine with wate producing secondary minerals like clays - Hydration - water molcules added ot rock minerals create new minerals of larger volume, like w...
• Describe the two forms of biological weathering in terms of biological weathering as a source of sediment - Tree roots - Decomposition releasing chemicals that weather minerals in the cliff surface
• Describe erosion by fluvial processes in terms of a source of coastal sediment - processes of erosion are the same as waves, during high energy high flow events - erosion in the upper catchment area is the main source of the rivers sediment load
• Describe deposition as a fluvial process in terms of a source of coastal sediment - Reduction in velocity when entering a static body of water, mud and silt can deposit and form a delta, or salt marsh
• Describe erosion as a aeolian process in terms of a source of coastal sediment (2) - Abrasion or corrasion wears down surface by grinding action and sand blasting of windbourne particles - Deflation is the lifting and removal of loose fine grained material fromearths surface forming shallow basins called deflation basins, attrition grinds windbourne particles together
• Describe Transporation as a aeolian processin terms of a source of coastal sediment - Saltation, suspension and surface creep, can carry sediment at 20km/h or more once entrained
• What are the Physical factors impacting coastal landscape systems (5) - Winds - Waves - Tides - Currents - Geology
• Describe winds in terms of physical factors impacting coastal landscape systems (2) - Waves are created by wind - Winds are influenced by the strength of the wind, the fetch of the wind, longer fetch leads to more energy accumulated being imparted onto the ocean
• Describe waves in terms of physical factors impacting coastal landscape systems (3) - A wave breaks when it slows down in shallower water and becomes steeper, this is called shoaling when a wave becomes too steep it breakes is called the plunge line - Three types of breaking wave, plunging, spilling and surging, constructive and destruvive waves differ on height, steepness, wave length and period - The wave anatomy consists of a crest, trough, height, wavelength, wave period, frequency and steepness - wave sdo not move the water forward just impart a circular motion on the water molecules
• Describe tides in terms of physical factors impacting coastal landscape systems (2) - Tides are caused by the gravitational pull of the moon and sun causing water on earth to move, the moon pulls water towards it creating a high tide and compensatory bulge at the opposite side of the earth, where there is a low tide - Spring tide is when the sun and moon align, so there is the greatest difference between high and low tide, Neap tide is the least difference between high and low water
• The the importance of tides and what they are influenced by in terms of physical factors impacting coastal landscape systems (3) - Tides aare influenced by the topography of the land, for example the funelling effect at the bay of fundy where tidal range is 16m - Tides are important because the larger the tidal range the more influence marine processes have on a cliff, in areas such as the river severn there are large tidal ranges of up to 14m - large areas are exposed to weathering - Tides help in the formation of mudlflats and saltmarshes where they deposit clay from the coast
• Describe Currents in terms of physical factors impacting coastal landscape systems (2) - Warm ocean currents transfer heat from low latitudes towards the poles, they affect western facing coastal areas where they are driven by onshore winds, cold ocean currents do the vice versa - Strength of current may have a limited impact on coastal systems but transferring heat can affect weathering rates
• Describe rip currents as part of currents in terms of physical factors impacting coastal landscape systems (3) - Rip currents form when wind and breaking waves push surface water towards the land, this causes a slight rise in water level along the shore - Water will tend to flow back to open water via the route of least resistence, where there is a local area which is lightly deeper or a break in an offshore sand bar, this can allow water to flow through more easily initating a rip current - Rip currents are important because they take sediment away from the coastline, they also help modify th...
• Describe lithology (geology) in terms of physical factors impacting coastal landscape systems (3) - Basalt - has strong interlocking crystals, very resistent to erosion and weathering, forms prominent features like steep cliffs and headlands - Limestone - Carbon rich rocks which dissolve in weak carbonic acid, vulnerable to carbonation weathering with lots of jointing allowing for erosional processes to act, but has enough strenght for features like arches to form - London clay and red crag - for example at walton on the naze, a product of previously weathered material, vulnerable to slumping...
• Describe structure (geology) in terms of physical factors impacting coastal landscape systems (2) - Structure concerns rock properties like bedding planes, jointing, porosity, faults, and permeability, complex structures are more easily attacked by marine processes due to larger surface area - Disconcordant coastlines results in differential erosion and higher sediment input, strata orientation determines the slope of the cliff, horizontally bedded strata results in steep cliffs, seaward strata results in a more gentle slope