About Heat Weathering

Heat weathering is a factor in the degradation of rock.

Exposure of materials to the sun's energy is the dominant force in heat weathering. It affects both natural materials such as rocks and man-made items. Various factors like texture and reflective properties affect how quickly certain items undergo heat weathering.

Geological Heat Weathering

When rocks are exposed to high temperatures they expand. At night, when sunlight is lacking, they cool and contract. Repeated heating and contraction causes rocks to form fractures, especially in areas of structural weakness, resulting in weathering of the rock into sediments.

Color

Light-colored materials reflect light and thus remain cooler when struck by sunlight. Darker colors absorb more light and heat up faster, therefore retaining increased temperatures longer and hastening the heat weathering process.

Texture

A rough or matte surface absorbs more light than a polished surface, which reflects light and stays cooler, thus resisting weathering.

Increased Chemical Reactivity

When materials are heated, the chemicals within or upon them increase activity. This leads to faster decomposition or faster diffusion of additives, contaminants and pollutants.

Ultraviolet Rays

When the ultraviolet rays in sunlight are combined with heat, the rate of heat weathering is increased.

References

• "Handbook of Material Weathering"; George Wypych; 2003
• Georgia Perimeter College: Weathering