Location – area studied 125095797560General area 5324475421005 The area studied is in the north of Kent and east of London. It lies between Herne Bay in the west and Wantsum channel in the east. The cliffs on this part of the coast are subject to high rates of erosion making it ideal for study in this coursework. Detailed map of the area 61150502072640-895350167640 Question 1 – Geomorphological processes This section details different geomorphological processes that have been made on the cliffs. Weathering – rock expansion The crack shown is a result of rock expansion which is a type of physical weathering. Rock expansion is where part of a cliff is eroded which takes the pressure off other parts of the cliff. Then the rock above it expands and cracks form Weathering – Granular disintegration Granular disintegration is where rocks such as sandstone which are porous become saturated with water. Minerals inside the rock dissolve in the water and when the water evaporated the minerals form crystals inside the rock which push off flakes off rock. These flakes of rock have fallen down the cliff face and collected at the bottom of the cliff as shown in the photo.-333375466090 Physical Weathering and Chemical weathering -600075118745 When rain water runs down a cliff face (rain wash) over time it wears the rock creating rills, which are shown in the picture. When water freezes in these rills they expand as the water expands, this is called freeze thaw.
Rain water with dissolved carbon dioxide in it becomes acidic and will dissolve any rock which is more than 50% calcium carbonate such as limestone. Plant matter in the ground will increase the acidity of the rain water as more carbon dioxide dissolves into it. This process is called carbonation. Chemical weathering -742950186055 Iron in the rock has oxidised forming a red brown stain, this is oxidisation. -371475533400Biological weathering Biological weathering is common on the cliffs as Sand Martins burrow holes into the cliff face. 1619251076325Biological weathering Roots of vegetation on the cliff force cracks to widen. This is biological weathering. Coastal erosion The rocks littered around the cave entrance are picked up when the tide comes in and thrown at the cliff, eroding it. This is called corrasion. Swash traps air in cracks in the rock. As the water is sucked away through back wash the pressure put on the air is realised causing it to rapidly expand making a small explosion. This widens the crack and is called hydraulic action 190501314450Coastal erosion Rock hit each other breaking off rock particles which smooths out the angular edges of the rocks. This is called attrition Erosion and formation of the cliffs -6000752882900-5143503825875-63817525400The cliffs are constantly eroded by the waves from the sea. The factors that affect the force of the waves are the strength of the wind, how long it blows for and the distance it blows over. The cliffs of Herne Bay are exposed to a very large fetch, shown in the diagram below. The arrow represents a possible direction of the wind. Once the wave reaches shallower water it will start to break and the swash will run up the beach and may reach the cliff, eroding it. The backwash will then drag beach material back down the beach. According to the direction of the wind, beach material is moved up and down the beach; this is called long shore drift and is shown by the diagram on the left. The waves undercut the cliffs and over time the raised section of the cliff will fall into the sea when there is no longer enough material underneath that section of the cliff to support it. Overtime the fallen material moves along the coast by long shore drift and is sucked into the sea by backwash. 19050381000Wave cut platforms This picture shows the extent of the erosion to the cliff. The rocks lying on the beach is a wave cut platform where the cliff once was. However over time the geomorphological process acting upon the cliff has pushed it back. The wave cut platform is evidence that the waves have undercut the cliff leaving, the unsupported upper section of the cliff which then falls away revealing the wave cut platform. Resultant landforms Cave -76200197485 Arch - in the future after further erosion the pillar or cliff in the middle may become a stack which there is currently none of at Herne Bay exam