Geomorphology By Kerala PSC: Biological weathering July 1, 2022
Geomorphology By Kerala PSC: Biological weathering
- Biological weathering is the removal of minerals and ions and physical changes due to growth or movement of organisms.
- Burrowing and wedging by organisms like earthworms, termites, rodents etc., help in exposing the new surfaces to chemical attack and assists in the penetration of moisture and air.
- Human beings by disturbing vegetation, ploughing and cultivating soils, also help in mixing and creating new contacts between air, water and minerals in the earth materials.
- Decaying plant and animal matter help in the production of humus, carbonic and other acids which enhance decay and solubility of some elements.
- Plant roots exert a tremendous pressure on the earth materials mechanically breaking them apart.
- Exfoliation is the flaking off of more or less curved sheets of shells from over rocks or bedrock results in smooth and rounded surfaces
- Exfoliation can occur due to expansion and contraction induced by temperature changes. Exfoliation domes and tors result due to unloading and thermal expansion respectively.
- Erosion is the process of removal of rock debris from one place to another.
- When massive rocks break into smaller fragments through weathering and any other process, erosional geomorphic agents like running water, groundwater,
- glaciers, wind and waves remove and transport it to other places depending upon the dynamics of each of these agents.
- The process of abrasion by rock debris carried by these geomorphic agents aids greatly in erosion.
- The landscape is worn down by the erosion, relief degrades. Weathering, mass-wasting and erosion are degradational processes.
- Erosion is largely responsible for continuous changes that the earth’s surface.
- The denudational processes like erosion and transportation are controlled by kinetic energy.
- The erosion and transportation of earth materials is brought about by wind, running water, glaciers are controlled by climatic conditions
- The work of the other two agents of erosion-waves and ground water is not controlled by climate.
- The erosional agents lose their velocity and hence energy on gentler slopes and the materials carried by them start to settle themselves.
- The coarser materials get deposited first and finer ones later.
- By deposition depressions get filled up.
- The same erosional agents viz., running water, glaciers, wind, waves and groundwater act as aggradational or depositional agents also