1. Exposure:
* Direct sunlight: UV radiation can break down the mineral bonds in granite, leading to color changes and cracking.
* Water: Water can seep into cracks and freeze, expanding and putting pressure on the rock, eventually causing it to break apart (frost wedging).
* Wind: Wind can carry abrasive particles that can chip away at the granite surface.
2. Chemical Composition:
* Mineral content: The specific minerals in granite (quartz, feldspar, mica) have varying degrees of resistance to weathering. Feldspar is more susceptible to chemical weathering than quartz.
* Chemical reactions: Water and atmospheric gases (CO2, O2) can react with minerals in granite, causing chemical breakdown and altering the rock's composition.
3. Biological Factors:
* Plants: Plant roots can grow into cracks in granite, expanding and putting pressure on the rock.
* Microorganisms: Some bacteria and fungi can produce acids that dissolve minerals in granite, contributing to weathering.
4. Other Factors:
* Altitude: Granite at higher altitudes is exposed to harsher conditions (more UV radiation, colder temperatures, more frost) and therefore weathers faster.
* Climate: Wet, humid climates promote chemical weathering, while arid climates favor physical weathering.
In summary, granite doesn't require any specific process before weathering. Its weathering process begins immediately upon exposure to the elements and is influenced by factors like sunlight, water, wind, chemical composition, biological activity, and climate.
