Weathering mantle
Also called: Regolith · Topic: Geomorphic Processes: Weathering, Mass Movement, Erosion and Soil Formation · NCERT: Class 11, Ch 5 "Geomorphic Processes"
Meaning
The weathering mantle is the layer of loose, broken and rotted rock that lies over solid bedrock. Its loose rock cover is also called regolith. It forms in place, as weather and climate break down the rock below. Its depth depends mostly on climate. It is deepest in humid tropics, where heat and water speed up chemical rotting. It is thin in hot deserts and in polar and tundra areas. The mantle matters because it is the raw material for soil. It also gives forests room to grow roots.
Example
In Kerala, along the wet Western Ghats, the weathered layer can be many metres thick before solid rock is reached. In the Thar Desert of Rajasthan, bare rock often lies just under a thin cover of broken pieces.
Don't confuse with
- Soil: the mantle is just weathered rock. Soil forms only when living things add humus (dark, rotted organic matter) and make the mass porous.