Question

In a single layer of an anticlinal, the dip isogons converge towards the inner surface (core). Which one of the following statements is correct for the curvature of the inner surface of this folded layer?

• A. Curvature of the inner surface > Curvature of the outer surface
• B. Curvature of the inner surface < Curvature of the outer surface
• C. Curvature of the inner surface = Curvature of the outer surface
• D. Curvature of the inner surface = Curvature of the median surface

Hint:

In anticlines, the curvature is more intense on the inner (core) surfaces due to compression, while the outer surfaces are stretched and have less curvature.

Answer 1

The Correct Option is A

Step 1: Understanding fold geometry.
In an anticline, the fold is convex upward, and the dip isogons (lines of equal dip) converge toward the inner or core surface. The layers on the outer side of the fold are more extended, while those on the inner side are more tightly compressed.
This results in higher curvature on the inner surface than on the outer surface of the fold.

Step 2: Analysis of curvature.
- Inner surface: Due to compression, the curvature on the inner surface of the fold is greater than on the outer surface. This makes the inner part of the fold steeper.
- Outer surface: The outer surface is more stretched and thus has less curvature than the inner surface.

Step 3: Conclusion.
The correct statement is that the curvature of the inner surface is greater than that of the outer surface. Hence, the correct answer is (A).
\[ \boxed{\text{Curvature of the inner surface > Curvature of the outer surface}} \]