What are the three principal types of weathering? Describe.

Three Principal Types of Weathering (अपक्षय के 3 प्रधान प्रकार):

Weathering is the in-situ (static) mechanical disintegration and chemical decomposition of rocks at or near the Earth's surface:

• 1. Physical / Mechanical Weathering:
  • Disintegration of rocks into smaller fragments without chemical alteration.
  • Mechanisms: Thermal expansion and contraction (Onion skin exfoliation in deserts), frost wedging (freeze-thaw in alpine fissures), and salt crystal growth.
• 2. Chemical Weathering:
  • Decomposition and structural alteration of rock minerals into new chemical compounds through atmospheric water and gases.
  • Mechanisms: Oxidation (rusting of iron rocks), Carbonation (dissolution of limestone forming Karst caves), Hydration, and Hydrolysis.
• 3. Biological Weathering:
  • Disintegration caused by living organisms—root wedging by growing tree roots splitting bedrock, burrowing animals (rodents, earthworms), and humic acid secreted by mosses/lichens.