Weathering And Mass Movement Flashcards
(18 cards)
What is mechanical weathering?
The physical breakdown of rocks into smaller fragments.
Includes processes like freeze-thaw, exfoliation, and salt weathering.
What is freeze-thaw weathering?
Occurs when water enters cracks in rocks, freezes, expands, and then thaws, causing the rock to break apart.
Common in the cliffs of the Holderness Coast.
What is exfoliation weathering?
Happens when heating and cooling causes rock layers to expand and contract, leading to peeling of outer layers.
Not very common in the UK.
What is salt weathering?
Where the growth and expansion of salt crystals within cracks in rocks cause them to fracture and break apart.
What is biological weathering?
The breakdown of rocks by plants and animals.
Plant roots and animal burrowing contribute to this process.
What is hydrolysis in the context of chemical weathering?
Water reacts with minerals, breaking them down and forming new compounds.
What happens during oxidation?
Oxygen reacts with minerals, especially those containing iron, forming new compounds like rust.
What is carbonation?
Acidic rainwater reacts with calcium carbonate in rocks like limestone, dissolving them.
Evident in the chalk cliffs of Flamborough Head.
What is dissolution in the context of chemical weathering?
Some minerals are soluble in water and dissolve, leading to the breakdown of rocks.
What is rockfall?
The rapid free-fall of rock from a steep cliff face.
What triggers a landslide?
The movement of rock and soil down a slope, often triggered by heavy rainfall or earthquakes.
What is mudflow?
The flow of water-saturated earth material down a slope.
What is slumping?
The downward and outward movement of rock and soil along a curved surface.
What is soil creep?
The slow, gradual downhill movement of soil, often imperceptible except over long periods.
What is rotational slumping?
A process affecting soft clay cliffs where added weight and lack of support cause clay to slide down a curved surface.
Commonly seen at Mappleton on the Holderness Coast.
What happens during rotational slumping?
Water soaks into soft boulder clay, making it heavy and slippery, leading to the clay sliding down a slip plane.
What role do waves play in rotational slumping?
Waves erode material at the base of cliffs, creating a notch and removing support from below.
What is negative feedback in the context of cliff erosion?
The time between a slump and the creation of a new wave cut notch, which can expose the cliff to more erosion and future slumping.
