Living Reference Work Entry

Encyclopedia of Engineering Geology

Part of the series Encyclopedia of Earth Sciences Series pp 1-2

Date: Latest Version

Biological Weathering

  • Maria Heloisa Barros de Oliveira FrascáAffiliated withMHB Geological Services Email author 
  • , Eliane Aparecida Del LamaAffiliated withInstitute of Geosciences, University of São Paulo

Synonyms

Biodeterioration​; Organic weathering; Weathering by organisms

Definition

Mineralogical components of rocks are altered and modified when exposed to Earth surface conditions in response to different atmospheric agents and insolation that may result in the disaggregation (physical weathering) or the decomposition (chemical weathering) of the rock. When these processes are assisted by biologic action they are called biological weathering.

Organisms may alter rock by both mechanical and chemical actions. The penetrating and expanding pressure of plant roots in cracks, fractures, pores, and other discontinuities may cause the rupture and disaggregation of the rock, if there are favorable conditions and the strength of the rock is lower than that applied by the roots (Fig. 1). Penetration and expansion of lichen thalli have a similar behavior to that of the roots since some thalli may expand up to 3900 per cent due to their high content o ...

This is an excerpt from the content