Key words physical geography Flashcards
(26 cards)
What is physical or mechanical weathering
caused by the changing temperature on rocks causing the rocks to break sometimes it can be helped by water
What is chemical weathering
Caused by rain water reacting with material grains in the rocks this occurs when the water is slightly acidic
What is biological weathering
When living organisms contribute to the process eg trees crack into the rocks
What is slumping
When the rain water gets through the cracks and the rocks fall down the cliff due to gravity
What is igneous rock formed from
Melted rock that has cooled and solidified
What is sedimentary rocks formed from
Layers at the surface of the earth either water or land
How is metamorphic rocks formed?
When rocks have Been subjected to high pressures or heat so high
What is rockfall
When weathered rocks fall due to gravity
What is longshore drift
The transportation of sand and pebbles along the coast by waves
Examples of sedimentary rock
Chalk sandstone
Examples of metamorphic rock
Slate
Example of igneous rock
Granite
What is mass movement
Cliff is full of water acts as a lubricant makes the material heavy then gravity causes it to slide
What is abrasion
Eroded Particles scrape and rub against the cliff eroding small peices
What is hydraulic action
Waves crash against the rock and compress the air putting pressure on the rock this repeated widens the crack and causes bites to break off
What is attrition
The rocks from the sea knocks into the cliff
What are characteristics of destructive waves
Have a high frequency
High and steep
Backwash more powerful than swash so material is removed
Characteristics of constructive wabes
Low frequency
Low and long
Powerful swash
Backwash is weaker so material is deposited on the coast
What is longshore drift
Waves follow directions of wind
Swash carries material up the beach
Backwash moves carries material down the beach at right angles
Over time material zigzags along the coast
What is deposition
Dropping of material
What is a concordant coastline
Bands of soft and hard rock run parallel to coastline
What is solution
Calcium based rocks are dissolved by the chemicals in seawater
How does a wave cut platform form
The waves erode away the lower bit of the cliff due to hydraulic action and abrasion
The cliff then collapses due to gravity and weathering
The cliff retreats and it happens again
How is a bar formed
When a spit grows a across the mouth of the bay creating a lagoon behind it
