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Topic 4 Assessment- Geography - Coggle Diagram
Topic 4 Assessment- Geography
Water and wave types
The wind blowing over water causes waves, wave size and energy depends on:
The fetch (how far the wave has travelled)
The strength of the wind
How long the wind has been blowing for
Wave types: Constructive and destructive waves.
Constructive waves have a strong swash and weak backswash. By having a strong swash this means the wave is bringing sediment to the beach and by having a weak backswash means there is not enough energy to remove the sediment. Constructive waves also occur in calm conditions, with low waveheight+wavelength.
Destructive waves have a weak swash and a strong backswash. A weak swash will mean that little sediment is being deposited at the beach, and a strong backswash means that sediment is being eroded by the waves. Beaches created as a result of destructive waves may look small, as a result of little to no construction. There may also be signs of major erosion on cliff walls. Destructive waves occur in stormy conditions with strong winds.
Types of weathering
There are three types of weathering: Freeze-thaw, Biological and Chemical weathering
Freeze thaw: 1. Water enters into a crack in the rock. 2. The water freezes, expanding the rock by about 9%. 3. When the water melts, the crack in the rock increases in size. 4. After repeating the steps, over the course of time the rock will break up.
Biological weathering: This is weathering that occurs due to plants or animals. The roots of plants can enter gaps of rock. As the roots get bigger, the crack within the rock expands. Eventually the rock breaks up.
Chemical weathering: Rainwater is slightly acidic and so too is seawater. When they come into contact with rock, the acid reacts with the minerals within the rock causing the rock to be dissolved over time.
Weathering vs Erosion: Weathering happens in situ whereas erosion transports sediment and materials.
Types of mass movement
Rockfall: Bits of rock fall of the cliff face, most likely due to freeze-thaw weathering.
Mudflow: Saturated soil(filled with water) flows down a slope
Landslide: Large blocks of rock slide downhill.
Rotational Slip: saturated soil slumped down a curved surface.
Erosion: There are 4 types of erosion
Hydraulic Action: The sheer force of the water smashing against the cliff face. Air become trapped in the rock causing it to break
Abrasion: The 'sandpaper effect'. Pebbles grind along the floor like sandpaper, over time the pebbles become more round.
Attrition:When rocks the sea is carrying knock into eachother causing them to round out and become finer.
Solution: When seawater dissolves certain types of rock e.g.limestone.
Headlands and bays are formed on a discordant coastline this is because of the alternating bands between hard rock and soft roack
The most important factor that affects costal landscapes is the strength of the waves for example destructive waves they have characteristics such as being tall and steep weak swash strong backwash
Caves occur when waves force their waves into cracks in a cliff face
If the cave is formed in a headland it may eventually break through to the other side forming a arch
Spits is a extended stretch of beach formed when prevailing wind blows at an angle the coastlin
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Sub arial process process of weathering and mass movement