Question

Mixing of soil matrix within a pedon resulting in irregular or broken horizons over permafrost

• A. Eluviation
• B. Pedoturbation
• C. Illuviation
• D. Cryoturbation

Hint:

The prefix "Cryo" refers to extreme cold or ice. Cryoturbation is the diagnostic pedogenic process for the Gelisols soil order.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Pedoturbation refers to the physical mixing of the soil profile. When mixing is driven by a specific physical force (such as ice, water, or gravity), it is classified by its physical mechanism.

Step 2: Detailed Explanation:
- Cryoturbation (frost churning) is the physical mixing of the soil matrix caused by freeze-thaw cycles.
- It is a dominant process in cold regions underlain by permafrost (characteristic of Gelisols).
- The formation and melting of ice lenses expand and contract the soil, forcing soil materials to move. This disrupts, shears, and breaks the soil horizons above the permafrost table.
- Pedoturbation is the general term for soil mixing (including bioturbation).
- Eluviation and Illuviation are translocation processes (leaching and deposition), not physical churning.

Step 3: Final Answer:
Mixing of soil matrix over permafrost is called Cryoturbation.