Question

Based on the given stereographic projection, the fold can be classified as

• A. reclined fold
• B. vertical fold
• C. overturned fold
• D. non-plunging fold

Answer 1

The Correct Option is C, D

To classify the fold based on the given stereographic projection, we must understand the characteristics of different types of folds:

• Reclined Fold: In a reclined fold, the hinge line is horizontal, and the axial plane is inclined.
• Vertical Fold: Here, both the axial plane and the fold axis are vertical.
• Overturned Fold: One or both limbs are tilted beyond vertical, causing the strata to dip in the same direction.
• Non-plunging Fold: The hinge line is horizontal, meaning the fold does not plunge into or out of the ground.

In the provided stereographic projection image, we observe the following:

1. The axial plane is slightly inclined, which indicates the possibility of overturning.
2. Both limbs appear to be dipping in the same direction, indicative of an overturned nature.
3. The hinge line seems horizontal, which is a characteristic of non-plunging folds.

Based on these observations, the fold is classified as:

• Overturned Fold: Due to the limbs dipping in the same direction.
• Non-Plunging Fold: Because the hinge line is horizontal.

Therefore, the correct answer is overturned fold and non-plunging fold.