Question

Select the answer that is a CORRECT match for the three types of unconformities. (Grey bands = sediments, [ + ] = igneous rock). 

• A. P–2; Q–3; R–1
• B. P–2; Q–1; R–3
• C. P–1; Q–3; R–2
• D. P–3; Q–2; R–1

Hint:

Remember: Disconformity = Parallel layers; Non-conformity = Igneous/Metamorphic contact; Angular = Tilted below flat beds.

Answer 1

The Correct Option is B

Step 1: Understanding types of unconformities.
Unconformities represent gaps in the geological record due to erosion or non-deposition. They are identified by the relation between older and younger rock layers.
Step 2: Classification.
- Disconformity: Parallel sedimentary beds separated by an erosional surface (same orientation).
- Non-conformity: Sedimentary rocks deposited over igneous or metamorphic rocks.
- Angular Unconformity: Tilted or folded beds overlain by horizontal beds.
Step 3: Matching.
P–3, Q–2, R–1 corresponds correctly.
Step 4: Conclusion.
Hence, the correct answer is (D) P–3; Q–2; R–1.