Question

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

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

Hint:

Cryo = cold. Cryoturbation is commonly found in tundra and permafrost regions.

Answer 1

The Correct Option is D

Cryoturbation is the process involving the mixing of soil layers due to freeze-thaw actions, especially over permafrost, causing horizon disturbance.

Answer 2

Elimination approach: Eluviation is the downward removal of dissolved or suspended material from an upper soil horizon, and illuviation is the deposition of that material in a lower horizon, both describing vertical translocation, not mixing caused by freezing. Pedoturbation is the general umbrella term for any mixing of soil material (by roots, animals, shrink-swell, or freeze-thaw), so it is too broad to be the specific answer.
The process specifically driven by repeated freezing and thawing above permafrost, which churns and disrupts soil horizons into irregular, broken patterns, has its own specific name, cryoturbation (a particular type of pedoturbation restricted to periglacial/permafrost environments).