PHYSICAL: Coastal landscapes and processes Flashcards
Mechanical weathering- FREEZE THAW
When water freezes it expands by 10% causing the break down of rock
Chemical weathering- ACID RAIN
Rainwater is slightly acidic. when rain falls on rock a weak chemical reaction takes place causing the rock to weaken and breakdown
Biological weathering
roots of growing plants can widen cracks in rocks causing them to breakdown
Define mass movement
The downhill movement of material due to gravity
Mass movement- SLIDING
Material moves along a surface usally beddding plane. large amounts of rock move downsslope
Mass movements- SLUMPING
Rain seeps through permeable rock. at the junction with an imperable rock, the saturated soil and weaker rock slumps in a rotational manner along a curved surface
Mass movements- ROCK FALLS
Pieces of rock from an eroded cliff fall, usually occurs when a base of a cliff eroded leading to rocks above being unsupported
Erosion- ABRASION
When fragments of rock are picked up by the waves and thrown against cliff face causing pieces of rock to fall off
Erosion- ATTRITION
Rocks and pebbles carried by waves are reduced in size when they collide against each other and the cliff face.
Erosion- HYDRAULIC ACTION
When waves crash against the cliff and weight of water causes the breakdown of rock. air is also compressed into cracks causing pressure to build up and break down rocks
Erosion- SOLUTION
Chemical reaction on rocks by seawater
- chalk
- limestone
Transport- TRACTION
Large boulders ROLLED along the seabed by waves
Transport- SALTATION
Smaller stones are BOUNCED along the seabed
Transport- SUSPENSION
Sand and small particles are CARRIED along in the flow
Transport- SOLUTION
Some minerals DISSOLVED in the seawater and are carried along the flow
Process of longshore drift
1) sediment created from erosion of the cliffs
2) action of the swash moves in at 45 degrees
3) this is in the direction of the prevailing wind
4) the action of the backwash will bring the sediment back down at 90 degrees due to gravity
5) as waves hit the beach this zigzag process continues
Define deposition
deposition occurs when there isnt enough energy to carry eroded material any futhur
What is a CONCORDANT coast
A coastline where bands of alternate geology run parallel to the coast
What is a DISCORDANT coast?
Coastline where bands of alternate geology run perpendicular to the shore
What are IGNEOUS rocks?
Rock that has formed from volcanic activity often cooled from magma on the earths surface
What are METAMORPHIC rocks?
Rock formed under intense pressure and heat, often close to tectonic plate boundaries
What are SEDIMENTARY rocks?
Formed from the broken remains of sediment and other rocks that have been compressed and cemented together over thousands of years
