A tunnel-like structure created by a burrowing animal and filled with soil material from another horizon is called a

• A. Krotovina
• B. Root cavity
• C. Burrow fill
• D. Paleochannel

Answer: (A)

In sedimentary geology, a tunnel-like feature made by a burrowing animal that later gets backfilled with soil from a different horizon is called a krotovina. This term specifically describes a biogenic burrow that has been filled with material from another layer, creating a distinct, backfilled intrusion within the host rock. The idea is that the burrow existed first, and the fill came from a different horizon, which is what sets a krotovina apart.

This is why it’s the best choice here: it captures both the origin as a burrow and the later infilling with sediment from another horizon. A root cavity is formed by plant roots, not a burrow backfilled from a different horizon. Burrow fill refers to the material inside a burrow rather than the feature itself. A paleochannel is an ancient river channel deposit, not a small biogenic tunnel backfilled with different horizon material.