1. Emergent Coastal landscapes (sea level fall)
1.1. Raised Beaches
1.1.1. Raised beaches are areas of former shore platforms left at a higher level than current sea level
1.1.1.1. Often found a distance inland from present coastline, behind the beaches it is common to find abandoned cliffs and wave cut notches
1.1.2. Formation of Raised Beaches
1.1.2.1. Land rises as a result of isostatic rebound during interglacial periods
1.1.2.1.1. Former beaches and wave cut platforms are now raised above the present sea level due to isostatic change
1.1.3. Example
1.1.3.1. Common in areas like Western Scotland and the Isle of Portland
1.1.3.1.1. Isle of Portland in Dorset has a raised beach formed 125,000 years ago from isostatic rebound, 15m above the present day sea level
1.2. Abandoned Cliffs
1.2.1. Cliffs that have been left above the erosional zone by falling sea levels
1.2.1.1. Normally found behind raised beaches, a compilation of arches, caves and stacks etc
1.2.2. How is it formed
1.2.2.1. Formed through marine erosion when it could be accessed by marine processes, containing a range of features like wave cut notches, caves and arches a significant distance behind the coastline due to rapid drop in sea level
1.2.3. For example Isle of Arran has a raised beach 5m above sea level including abandoned cliffs
1.3. Modification of Emergent landforms
1.3.1. No longer affected by wave processes, but can be affected by weathering and mass movement
1.3.2. Mechanical Weathering
1.3.2.1. Cliff tops are affected by frost shattering processes and cryoturbation in the last glacial period
1.3.2.1.1. Results in the shattering and contortion of limestone cliff tops
1.3.3. Increased Biological Weathering
1.3.3.1. Warmer and wetter conditions lead to the development of vegetation cover on abandoned cliffs increasing the impacts of biological weathering
1.3.4. Increased Chemical Weathering
1.3.4.1. Further warming of the climate predicted, chemical weathering will perhaps become more influential
1.3.4.1.1. Like carbonation of limestone cliffs
2. Climate Change Sea Level Change
2.1. Natural causes of climate change
2.1.1. Milankovitch Cycles
2.1.1.1. Eccentricity
2.1.1.1.1. The change in the size of Earths orbit
2.1.1.1.2. Completes full cycle every 400,000 years
2.1.1.2. Obliquity
2.1.1.2.1. Earth tilts on its axis from 22 to 24.5 degrees and back every 40,000 years
2.1.1.3. Precession
2.1.1.3.1. Earth gyrates a full circle on its axis every 22,000 years
2.1.1.4. If all three cycles are in a certain phase at the same time an ice age can begin and sea levels will fall
2.1.2. Sunspots
2.1.2.1. Variations in amount of energy produced by the sun with a solar maximum every 11 years
2.1.3. Volcanic Eruptions
2.1.3.1. Changes in the composition of the atmosphere due to major volcanic eruptions
2.2. Eustatic Change
2.2.1. Sea level change of the volume of Earth's oceans
2.2.1.1. Change in total volume of sea water, like when ice sheets or glaciers melt
2.3. Isostatic Change
2.3.1. Result of an increase or decrease in the height of the land
2.3.1.1. When the height of the land decreases sea levels rise
2.3.1.2. During ice age the weight of ice causes land to sink hence sea levels rise (known as compression)
2.3.1.2.1. Isostatic rebound is where the land is alleviated from the weight of the ice and rebounds in height
2.4. Glacial Period
2.4.1. Riss glacial period (108,000 years ago)
2.4.1.1. Temperature 7 degrees lower than today
2.4.1.1.1. Sea levels dropped by 100 metres, 83 metres lower than today
2.4.2. Decrease in global temperatures leads to more precipitation in the form of snow
2.4.2.1. Eventually snow turns into ice and is stored on land in cryosphere
2.4.2.1.1. Reducing the volume of water in the ocean store and worldwide sea level fall
2.4.2.2. As temperatures fall water molecules contract leading to an increased density and reduced volume
2.4.2.2.1. 1 degree fall in temperatyre coul cause 2m fall in sea level
2.5. Inter glacial Period
2.5.1. Tyrrhenian Inter-glacial (130,000 years ago)
2.5.1.1. Temperature 3 degrees higher than today
2.5.1.1.1. Sea levels 20 metres higher than today
2.5.2. Weight of the ice puts pressure on the land
2.5.2.1. When the ice melts during the interglacial period the land rebounds and increases in height, known as isostatic rebound
2.5.2.1.1. Sea levels are further increased by a high input from rivers and expansion of water molecules
3. Submergent Coastal landscapes (sea level rise)
3.1. Formation of Submergent Coastal landscape
3.1.1. At the end of the Wurm glacial period 250,000 years ago the temperatuures were 9 degrees lower than today and sea levels 90m lower
3.1.1.1. Since then temperatures and sea level have risen to their present level during the period of sea level rise known as the flandrian transgression
3.1.1.1.1. Resulting in the formation of submergent coastlines
3.2. Rias
3.2.1. These are sumberged river valleys intially formed by fluvial erosion
3.2.2. How is it formed
3.2.2.1. The lowest part of the rivers course and its nearby floodplains are completley drowned but the higher land forming the tops of the valley sides remain exposed
3.2.2.2. In the cross section rias have relatively shallow water, becoming deeper nearer the centre
3.2.2.3. Several rias can be found on the south coasts of Devon and Cornwall including those at Salcombe and Kingsbridge
3.2.3. Influence of sea level rise
3.2.3.1. During interglacial periods where sea levels rise, increased deposition occurs as rivers had less energy for erosion
3.2.3.1.1. Results in the formation of exposed sand banks at low tide
3.3. Fjord
3.3.1. Submerged U shape glacial valleys with steep cliff like valley sides with uniformly deep water of up to 1000m
3.3.1.1. Tend to have a much straighter profile than Rias as the glacier would have removed any interlocking spurs present
3.3.2. A threshold is formed towards the shallower, warmer, seaward end of the fjord due to lower rates of glacial erosion
3.3.3. influence of sea level rise
3.3.3.1. Due to the depth of water that occupied fjords during flandrian transgression, marine erosion rates remained high and the fjords were further deepened
3.3.3.1.1. In some areas there has been an infilling of sediment, deposited by meltwater from glaciers that are still present
3.4. Shingle Beach
3.4.1. How is it formed
3.4.1.1. Sea levels fall and land based ice grows, large areas of 'new' land emerges from the sea
3.4.1.1.1. Sediment accumulates on this surface deposited by rivers and meltwater streams
3.4.2. The tombolo at Chesil beach is thought to have been formed this way during the flandrian transgression
3.4.2.1. As sea levels rose the sediment in the english channel was carried 50km northeast by the southwesterly prevailing winds becoming attatched to the Isle of portland at one end and mainland at the other
3.5. Modifications of these landforms
3.5.1. Rias and Fjords
3.5.1.1. Increased sea level rise will result in increased wave erosion
3.5.1.2. Sub aerial processes may decrease the steepness of valley sides
3.5.2. Shingle Beaches
3.5.2.1. Increasing sea level will push shingle beaches further towards the coastline
3.5.2.1.1. Chesil beach is moving 17cm northeast per year