Question

Which of the following rock structures is/are fold(s)?

• A. Antiform
• B. Horst
• C. Syncline
• D. Synform

Hint:

- Folds → Antiform, Synform, Anticline, Syncline.
- Fault-related structures → Horst (upthrown block), Graben (downthrown block).

Answer 1

The Correct Option is A

Step 1: Recall the concept of folds.
A fold is a bend or curvature in rock layers formed due to compressional forces. Folds are structural features, typically including anticlines, synclines, antiforms, and synforms. Step 2: Examine each option.
- Antiform: A fold that is convex upward (arch-like), but the relative ages of the layers are not considered. → A fold
- Horst: A raised block of crust bounded by normal faults. It is a fault-controlled structure, not a fold.
- Syncline: A fold concave upward (trough-like), where the youngest rocks occur at the core. → A fold
- Synform: A fold that is concave upward, regardless of the relative ages of the strata. → A fold Step 3: Conclusion.
Thus, the fold structures among the given options are: \[ \boxed{\text{Antiform, Syncline, Synform}} \]