One topic looked at in GCSE Geography is weathering. This is the natural process which causes the breakdown of rocks and minerals by chemical, biological or physical agents and is not to be confused with erosion. Erosion is the process in which material is moved whereas weathering occurs in situ.
Weathering is the breakdown of rocks, soil and naturally occurring minerals, as well as all the artificial minerals that have been made by human activity, such as bricks and concrete. Weathering is the process that eventually turns mountains into grains of sand on a beach.
Various factors influence the rate of weathering, including:
- Geology - softer rocks, rocks with more cracks, and the chemical composition of the rocks will all influence the amount and type of weathering. Granite is one of the harder rocks that weathers much more slowly than sedimentary rocks.
- Vegetation - whilst areas with a high biological load will suffer from rapid biological weathering, the rocks there may be protected by the vegetation from rapid changes in temperature and also be subjected to less attack by water. Vegetation also stabilises river banks preventing hydraulic attack.
- Climate - rainfall, temperature range and the amount of sunshine will all influence the amount of weathering.
- Shape of the land - steep areas will suffer different types of weathering to shallow or flat lands. The steep areas will be more exposed to types of physical weathering, but may have reduced chemical attack.
- Human Impact - we can influence all forms of weathering whether chemical, biological or physical. Deforestation, putting more corrosive chemicals into the atmosphere and waterways, physically moving across landscapes; all of these can breakdown more rock, whilst protective measures can decrease weathering in localised areas.