Weathering

 

“Weathering is a complex phenomenon involving a number of processes and is influenced by various factors “ Elaborate ? (200 Words)
Weathering is defined as mechanical disintegration and chemical decomposition of rocks (in situ) through the actions of various elements of weather and climate.
Controlling Factors of Weathering:
The nature and magnitude of weathering differ from place to place. For example
disintegration of rocks is more effective in hot and dry region coupled with those regions where frost action is more dominant. While chemical decomposition is more prevalent in hot and humid and temperate humid regions. Also other factors include:
  1. Composition and Structure of rocks.
  2. Nature of Ground Slope
  3. Climatic variations
  4. Floral effects
Types of Weathering Processes And Weathering Agents:
Generally Weathering Processes are divided into physical, chemical and biochemical processes which are intimately interrelated.
1. Physical weathering:
—Block disintegration due to temperature or due to frost.
—Granular disintegration due to temperature.
—Exfoliation due to temperature and wind.
Prominent weathering agents includes, Moisture and Water, Frost, Insolation, and Wind.
2. Chemical Weathering: these may include Oxidation, Carbonation, Hydration and Hydrolysis. The Weathering agents here includes oxygen, CO2, and Hydrogen.
3. Biochemical weathering: Plant weathering, Animal weathering, Biochemical weathering and Anthropogenic weathering. The various weathering agents involves Vegetation and Animals (mainly microorganisms)
Are physical and chemical weathering processes independent of each other? If not, why? Explain with examples. (150 Words)
weathering is a process in which “attrition” of existing geological structures takes
place. As physical and chemical forces are coupled on earth, the weathering also
takes place due to combination of them except in a few cases.
ways in which physical attrition takes place-
  1. heat- periodic expansion and contraction of rocks.
  2. rain- hydraulic action.
  3. attrition- due to “sand hitting”.
  4. friction- ex. rolling of rocks and other factors.
  5. biological-penetrative forces by roots of plants.
  6. corrosion- due to glacial movement over rocks.
ways in which chemical attrition takes place
  1. solution- alkaline and acid solutions
  2. rains- with co2/so2 may lead to chemical weathering.
  3. biological- humus/ decomposition on rocks may lead to some kind of attrition.
as these forces are “largely interdependent” and “mutually cooperative” weathering is resultant of both physical and chemical forces.
examples for exceptions places like” antarctic” where” rain is rare and pure” and biological activity is “near nil” chemical weathering is uncommon. in such cases physical forces alone will take place.