The Coastal Zone Coasts Are Constantly Changing Flashcards
Explain physical weathering in terms of temperature changes?
An example of this is onion skin weathering.When a rock gets hot it expands a little, and when a rock gets cold it contracts a little. If a rock is heated and cooled many times, cracks form and pieces of rock fall away.
Explain physical weathering in terms of freeze thaw weathering?
What is biological weathering?
Animals and plants can wear away rocks. This is called biological weathering. For example, burrowing animals such as rabbits can burrow into a crack in a rock, making it bigger and splitting the rock. Plant roots can grow in cracks. As they grow bigger, the roots push open the cracks and make them wider and deeper.
What is chemical weathering?
Rainwater is naturally slightly acidic because carbon dioxide from the air dissolves in it. Minerals in rocks may react with the rainwater, causing the rock to be weathered. Eg. acid rain.
What is rockfall?
Rapid free-fall of rock from a steep cliff face. Rock fragments fall from the face of the cliff because of the action of gravity. This is made worse by freeze-thaw action loosening the rock.
What is mudflow?
It’s a sudden movement which occurs after periods of heavy rain. When there is not enough vegetation to hold the soil in place, saturated soil flows over impermeable sub soil.
What is rotational slip?
Saturated soil and weak rock slumps along a curned surface.
What is a landslide?
Blocks of rock and earth slide downhill along diagonal bedding planes. Most likely to occur after periods of heavy rain.
What are the types of transportation and their definitions?
Solution - minerals are dissolved in the water and carried along in solution.
Suspension - fine light material is carried along in the water.
Saltation - small pebbles and stones are bounced along the river bed.
Traction - large boulders and rocks are rolled along the river bed.
Bits of rock and sand in waves grind down cliff surfaces like sandpaper. What is the name of this process of erosion?
abrasion
Waves smash rocks and pebbles on the shore into each other, and they break and become smoother. What is the name of this process of erosion?
attrition
Acids contained in sea water will dissolve some types of rock such as chalk or limestone. What is the name of this process of erosion?
solution
Air may become trapped in joints and cracks on a cliff face. When a wave breaks, the trapped air is compressed which weakens the cliff and causes erosion. What is the name of this process of erosion?
hydraulic action
Explain deposition.
when a river loses energy, it will drop or deposit some of the material it is carrying.
Deposition may take place when a river enters an area of shallow water or when the volume of water decreases - for example, after a flood or during times of drought.
Deposition is common towards the end of a river’s journey, at the mouth.
Deposition at the mouth of a river can form deltas - for example, the Mississippi Delta
