What is weathering?
Weathering is a process which breaks down rock. Weathering can be the results of three actions/processes caused by –
- Chemical processes (chemical weathering)
- Animal or plant actions (biological weathering)
- Mechanical processes (mechanical weathering)
1. Chemical weathering
Chemical processes can be oxidation, carbonation and solution. Water that dissolves acidic gases can form a solution that easily dissolves softer rock and thus break down the bonds that holds the rock together. The result can be a rock that starts to ‘fall’ apart. Chemical weathering occurs most frequently in area of higher temperatures and rainfall.
(Source:http://www.kidsgeo.com/)
2. Biological weathering (also biotic weathering)
Biotic weathering can be any kind of weathering caused by the actions of any living organism. Tree roots force its way into cracks in rocks and acts as a wedge, forcing the crack wider.
3. Mechanical weathering
In mechanical weathering the chemical composition of rocks doesn’t change. They simply get torn apart by force. These forces can be earth movements, friction caused by objects moving, wind and temperature fluctuations. When rocks heat up (day), they expand and when they cool (night), they shrink. This continuous process will cause the rock’s outer layer to start peeling of like an onion. This type of mechanical weathering is known as exfoliation.
Mass wasting
Due to the gravitation force of the earth objects, no matter the size, can be pulled down to the lowest point. The moment materials from the earth’s crust moves due to gravity it is known as mass wasting.
Mass wasting can occur in many forms such as –
- Rock falls
- Soil creep
- Land slides
- Mud flows
1. Rock falls
This is probably the most common type of mass wasting. At steep slopes such as cliffs boulders, rocks, pebbles and smaller pieces of rock fall to the ground lower down on a regular basis. The accumulation of theses falling debris can result in the formation of a talus at the base of the steep slope.
2. Soil creep
Soil creeps happens at a very slow pace, many times not even visible for by passers. Soil can slide over a solid rock layer and result in an entire slope to move down a hill.
3. Land slides
Larger areas along slopes start to slide down a hill. It can be caused by rain or simply due to the gravitational pull.
4. Mudflows
Mudflows can happen very rapidly. After a long period of rain soils along steep slopes become saturated and start to flow down a slope.
