Plutonic rocks are formed when lava cools ______.
Show answer & explanation
Correct answer: C
Explanation
The Correct Answer is option 3 i.e. In the crust .
Plutonic rocks, also known as intrusive igneous rocks, are formed when magma cools and solidifies slowly beneath the Earth’s surface, specifically within the crust. Because the cooling process is slow, large crystals have time to form, giving these rocks a coarse-grained texture. Common examples include granite, diorite, and gabbro. In contrast, volcanic (extrusive) rocks form when lava cools rapidly at the surface, resulting in fine-grained textures. Plutonic rocks play a key role in forming the foundation of continents and reveal information about the Earth’s internal geological processes.
Other options:
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Asthenosphere: Too deep and molten for rock crystallization.
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Core: Composed mostly of iron and nickel, not silicate rocks.
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At the surface: Forms volcanic, not plutonic, rocks.