Factors Affecting the Rate of Weathering

1. Climate

Temperature:

• In warm climates, chemical weathering (e.g., carbonation) is faster due to higher temperatures.
• In cold climates, freeze-thaw weathering occurs, where water enters cracks in rocks, freezes overnight, expands, and breaks the rock apart. Precipitation:

In wetter climates, chemical weathering (like hydration and hydrolysis) is more active, while in dry climates, physical weathering predominates.

2. Rock Type

• Softer rocks like limestone break down faster than harder rocks like granite. For example, limestone undergoes chemical weathering when it reacts with acid rain through the process of carbonation.
• Rocks that are permeable (allow water to pass through them) weather faster. Rocks like sandstone have many small pores, allowing water to seep in and cause weathering.

3. Vegetation

Roots:

• The growth of plant roots into cracks in rocks can cause physical weathering. As roots grow, they exert pressure, gradually breaking the rock apart.

4. Human Activity

Construction and Quarrying:

• Human activities like mining and quarrying expose rocks to the weathering process by breaking them into pieces. This leads to faster weathering.

Pollution:

• Pollution increases the acidity of rain, creating acid rain. This speeds up chemical weathering, particularly in areas with high industrial activity.

5. Time

• Regolith: Over time, the weathering process produces regolith, the loose material that forms on the surface. The longer the exposure to weathering agents, the more regolith is produced, and the more lithified (turned into rock) the material can become.

Key Terms

Term	Definition
Weathering	Breakdown or decay of rocks on or near the Earth's surface
Regolith	Pieces of weathered rock
Scree or Talus	A mass of small weathered rock that often forms a pile at the base of a cliff
Precipitation	Collective name for rain, hail, sleet, snow
Diurnal Temperature Change	Large change in temperature between day and night
Lithified	To turn to rock
Permeable	Allows water to pass through it