1. Composition:
* Mineral Hardness: Rocks composed of softer minerals (like calcite in limestone) are more easily weathered by abrasion or chemical reactions than rocks with hard minerals (like quartz in granite).
* Solubility: Rocks with minerals that are easily dissolved by water (like halite in rock salt) are susceptible to chemical weathering.
* Chemical Reactivity: Rocks with minerals that readily react with water or acids (like feldspar in granite) are vulnerable to chemical weathering.
2. Climate:
* Temperature: Fluctuations in temperature (like freeze-thaw cycles) cause physical weathering by expanding and contracting rock.
* Moisture: Water plays a key role in both chemical and physical weathering. Rainwater can dissolve minerals, while freeze-thaw cycles cause mechanical breakdown.
* Presence of Acids: Acid rain, caused by atmospheric pollution, accelerates chemical weathering.
3. Surface Area:
* Fractures and Joints: Rocks with cracks and fractures provide more surface area for water and other weathering agents to attack.
* Grain Size: Rocks with smaller grain sizes have more surface area exposed to weathering agents compared to rocks with larger grain sizes.
* Shape: Angular rocks have more surface area than rounded rocks, making them more susceptible to weathering.
It's important to note that these factors often work together to influence how quickly and in what ways a rock will weather.
