- Decomposing vegetation (humus) releases humic acid.
- This acid attacks calcium, magnesium and iron minerals within rocks in a process called chelation.
- The respiration of bacteria and plant root increases carbon dioxide levels within the soil thus accelerating the process of carbonation.
- Lichen extracts iron from rocks via reduction.
- Human and economic activities are realising more and more carbon dioxide into the atmosphere together with other chemicals such as sulphur dioxide and nitric oxide.
- These gases then dissolved into rain water to form acidic solutions.
- Acid rain attacks and corrode limestones and at a lesser rapid rate sandstones.
- Also the acidic solutions tend to free up oxygen ions thus fueling the process of hydrolysis.
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