Question

Identify the pair from the following list that is NOT correctly matched.

• A. Caldera – stratovolcano
• B. Pillow basalt – subaerial eruption
• C. Ropy lava – pahoehoe flow
• D. Amygdales – filled vesicles

Hint:

Pillow basalt forms underwater when lava cools rapidly upon contact with water, creating characteristic pillow-shaped structures.

Answer 1

The Correct Option is B

Step 1: Understanding the question.
The question asks to identify the incorrectly matched pair. Each pair relates to volcanic features, and we need to identify which one is not accurate.

Step 2: Analyzing the options.
(A) Caldera – stratovolcano: This is correct. A caldera is typically associated with the collapse of a stratovolcano.
(B) Pillow basalt – subaerial eruption: This is incorrect. Pillow basalt forms in underwater eruptions, not subaerial (land-based) eruptions.
(C) Ropy lava – pahoehoe flow: This is correct. Pahoehoe lava flows are characterized by a smooth, ropy texture.
(D) Amygdales – filled vesicles: This is correct. Amygdales are cavities in volcanic rocks that are filled with secondary minerals.

Step 3: Conclusion.
The correct answer is (B) Pillow basalt – subaerial eruption because pillow basalts form during underwater eruptions.