Zusammenfassung der Ressource
Weathering and Mass movement
- Weathering
- Processes that erode cliffs at their top and face
are called weathering processes or sub-aerial
weathering processes
- Physical/mechanical weathering
- Breaks into smaller pieces
- Freeze thaw
- Water fills a crack in a rock and
freezes, it will expand and create a
strain on the rock. A result of this
process repeating over and over
causes the rock to break
- Salt crystallisation
- When salt water fills a crack in a
rock. When the water evaporats
the salt crystals are left behind
and over time they build up,
separating the rock and
eventually splitting it.
- Chemical weathering
- Break down into
component parts
- Carbonation
- Rain water is naturally acidic and the acids
often react with the chemicals in rock. It is
affective against rock with a high calcium
carbonate content like limestone.
- Rust
- When water causes
metals (e.g. Iron) to rust
- Hydration
- Rocks with a high clay content are
capable of absorbing water. This causes
them to swell and eventually break
into separate elements.
- Hydrolysis
- When hydrogen in rocks react
with water, causing the
minerals to chemically break
down
- Biological weathering
- Carried out by living organisms
- Combination of both physical and chemical weathering
- E.g. Rabbits physically eroding rocks when burrowning. Excretions chemically erode rocks
- Mass Movement
- Rock slides
- Chunks/slabs of rock break awaty from
the cliff. They could be layers of surface
rock that slide down the cliff face.
- Rock falls
- Rocks break and fall off of a cliff due
to freeze-thaw
- Slumps
- Typically occurs after heavy periods of rainfall.
The top layer of the cliff face becomes saturated
with rainwater, and as a result of the water
logging it can't support its own weight and the
whole section of material slides off
- Downward movement of weathered
rock under the influence of gravity