Weathering of Rock
- Created by: charlieforster
- Created on: 31-03-17 09:17
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- Weathering of Rock
- Chemical Weathering
- When C02 in the air dissolves into rain, a weak carbonic acid forms.
- This carbonic acid can dissolve some rocks (limestone), therefore rocks may become weaker.
- Because Limestone contains bedding planes and joints, the weathering can occur easily as water can pass through the rock cracks.
- The chemical weathering of limestone, or carbonation occurs when the rock is attacked by rainwater.
- Biological Weathering
- Biological weathering is weakening and disintegration of rock , via plants, animals and microbes.
- Growing plant roots can put pressure on the rocks when they grow and this can force them to crack and eventually break.
- Microbial activity breaks down rocks by altering a rocks chemical composition. This weakens the rocks structure.
- For example, Lichens (fungi/ algae) releases chemicals which break down rock minerals and the rock weakens. The algae then consumes this rock, leaving holes in the rock for other weathering to occur.
- Burrowing animals may create holes in the ground and move rock fragments to the surface, exposing the rock to more chemical, biological and physical weathering.
- Mass Movements
- The down-slope movement of materials on a slope by gravity is known as Mass Movement, or Mass Wasting.
- Factors affecting the rate of Mass Movement:
- How wet the ground is, this is because a wet ground will enable the land to slide easily.
- Angle of the land, an increase can cause the land to slide.
- How much vegetation coverage there is, this is because help to hold rock materials together thus reducing their movement on the earth’s surface.
- Chemical Weathering
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