Costal weathering, erosion and transport Flashcards
What are the 3 types of weathering
-mechanical
-chemical
-biological
What is mechanical weathering
The breakdown of rocks by physical processes, without changing its chemical composition
What is chemical weathering
The breakdown of rocks by chemical processes changing its chemical composition
What is biological weathering
The breakdown of rocks by living things like animals and plants
Mechanical weathering example
1… gets into … in the …
2.when the water … salt … form, as they form they … which puts … on the …
3. Repeated … of saltwater and the … of … widens the … and causes the rock to … up
1.seawater gets into cracks in the rock
2.when the water evaporates salt crystals form, as they from they expand which puts pressure on the rock
3. Repeated evaporation of saltwater and the forming of salt widens the cracks and causes the rock to break up
Chemical weathering example
- … has … dissolved in it, making it a weak … acid
2…. acid … with the rock that contains … carbonate eg c… so the … are …
- Rainwater has co2 dissolved in it, making it a weak carbonic acid
2.carbonic acid reacts with the rock that contains calcium carbonate eg chalk so the rocks are dissolved
What is mass movement
The shifting of rocks and loose material down a slope due to gravity
What conditions make mass movement more likely
-when the material is full of water
What are the 2 types of mass movement
Slumps and slides
What is a slump
The movement of rocks and loose material under the influence of gravity down along a curved surface
What is a slide
The movement of rocks and loose material under the influence of gravity down a straight line
What are the 4 erosional processes
-Hydraulic action
-abrasion
-attrition
-solution
What is hydraulic action
-When waves crash against rock forcing air into cracks putting a lot of pressure on the rocks
-when this process repeats the crack widens and the rock breaks apart
What is attrition
-when rocks collide over and over again becoming smaller and rounded
What is abrasion
-where rocks and sediment are thrown or scraped against another surface eroding it
What is solution
-where dissolves CO2 makes rivers and sea water slightly acidic, this acid reacts with some rocks like chalk and limestone, dissolving them
What are the 2 types of waves
-destructive
-constructive
What are destructive waves
-carry out … processes
-have a high …
-… and s…
-… is stronger than …
-create … beaches
-carry out erosional processes
-have a high frequency
-high and steep
-backwash is stronger than swash
-create steep beaches
What are constructive waves
-… material
-have a … frequency
-… and l…
-… is … than …
-creates … beaches
-deposit material
-have a low frequency
-low and long
-swash is stronger than backwash
-creates flat beaches
Longshore drift
The process by which material is moved along a coastline which is influenced by prevailing winds
4 processes of transportation
-traction
-saltation
-suspension
-solution
What is traction
-large peoples are rolled along the sea bed by the force of water
What is suspension
-small particles like silt are carried along in the current of the water
What is saltation
-pebbles are bounced along the seabed by the force of water
What is solution- transportation
-soluble materials dissolve in the water and are carried along
How does longshore drift work
- … follow the … of … winds
- Hit the … at an …
- the … carries … up the … in the same … as the …
- the … carried … back … the … at a … angle
- This … a … zag …
- Waves follow the direction of prevailing winds
- Hit the coast at an angle
- the swash carries material up the beach in the same direction as the waves
- the backwash carried material back down the beach at a right angle
- This creates a zig zag formation
What is deposition
When material being carried by water is dropped when the water slows down and looses energy and is no longer strong enough to carry its load
When are beaches built up
When the amount of deposition is greater than the amount of erosion
When does the amount of material deposited increase
-when there is lots of erosion elsewhere on the coats
-lots of transportation of material into the area
