Regolith

Definition

Regolith is "the layer of unconsolidated, weathered, broken rock debris, mineral grains, and superficial deposits which overlie the unaltered bedrock" of a planet or moon. It is formed in the weathering processes that occur in the lithosphere. The depth varies greatly depending on the, "intensity and duration of the weathering process." Within the tropics of Earth, it may be hundreds of metres deep, whereas in other regions, such as the Rocky Mountains, it can be practically nonexistent. [1]

Components

Earth's regolith is comprised of the following components: [2][3][4]

• Soil or pedolith
• Transported cover, including but not limited to glacial and gravitational flow.
• Volcanic ash and lava flow
• "Saprolith", which can be divided into;
  • Upper saprolite: oxidised bedrock
  • Lower saprolite: chemically reduced, partially weathered bedrock
  • Saprock: fractured bedrock. Weathering restricted to fracture margins
• Groundwater and water-deposited salts
• Biota and Organic Compounds
• Duricrust, which is formed by the cementation of saprolith, soils, and other transported materials into non-friable layers. Non-friable layers are unlikely to crumble and break into smaller pieces, and they are resistant to weathering and erosion.

References

1. Oxford University Press. "Regolith". Oxford Reference. https://www.oxfordreference.com/display/10.1093/oi/authority.20110810105721161#:~:text=A%20general%20term%20for%20the,which%20overlie%20the%20unaltered%20bedrock.
2. Ollier, Cliff; Pain, Colin (1996). "Regolith, soils and landforms". Chichester: John Wiley. ISBN 978-0471961215
3. Taylor, G.; Eggleton, R.A. (2001). Regolith geology and geomorphology. Chichester: J. Wiley. ISBN 978-0471974543
4. Scott, Keith M.; Pain, Colin (2009). Regolith science. Collingwood, Vic.: CSIRO Pub. ISBN 978-1402088599