Granite is an example of which type of rock?
- A.Intrusive igneous rock
- B.Extrusive igneous rock
- C.Chemically formed sedimentary rock
- D.Foliated metamorphic rock
Correct answer
Explanation
The correct answer is A, an intrusive igneous rock. Granite forms when magma cools slowly deep below the surface, which gives the crystals time to grow, so the rock is coarse and speckled. Such rocks are also called plutonic, and granite is the classic example used in textbooks.
Option B, extrusive igneous rock, describes lava that cools quickly on the surface, giving fine-grained rocks such as basalt and the frothy pumice that floats on water. Option C, chemically formed sedimentary rock, covers rock salt and gypsum, deposited when mineral-rich water evaporates. Option D, foliated metamorphic rock, covers banded rocks such as gneiss and schist; gneiss is in fact what granite becomes after metamorphism. So one rock name can move between families, and the process named in the question decides the answer.
Read the full article: Structure of the Earth and Rocks: Layers, Waves and Types
Practice Questions
View allThe boundary that separates the crust from the mantle is known as the
- A.Conrad discontinuity
- B.Mohorovicic discontinuity
- C.Gutenberg discontinuity
- D.Lehmann discontinuity
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Named after the Croatian seismologist who noticed that earthquake waves suddenly speed up at a certain depth, it marks the base of the crust and the top of the mantle, and is commonly shortened to the Moho.
Read the full explanation →Which of the following seismic waves cannot travel through liquids?
- A.Primary or P waves
- B.Secondary or S waves
- C.Surface or L waves
- D.All three types
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They are transverse waves, in which particles vibrate at right angles to the direction of travel, and such motion cannot be sustained in a fluid, so S waves die out at the outer core.
Read the full explanation →Marble is a metamorphic rock formed from which of the following parent rocks?
- A.Sandstone
- B.Shale
- C.Limestone
- D.Granite
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Limestone is a sedimentary rock made largely of calcium carbonate, and when heat and pressure recrystallise it without melting it, the result is marble, the stone used in the Taj Mahal and in the Dilwara temples.
Read the full explanation →The Deccan Trap of peninsular India is composed mainly of which rock?
- A.Granite
- B.Basalt
- C.Limestone
- D.Gneiss
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The Deccan Trap was formed by vast fissure eruptions in which lava spread over the surface and cooled quickly, giving a fine-grained extrusive igneous rock, basalt.
Read the full explanation →Fossils of ancient plants and animals are found mainly in which type of rock?
- A.Igneous rocks
- B.Sedimentary rocks
- C.Metamorphic rocks
- D.Plutonic rocks
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They are built up layer by layer as sediment settles over the remains of living things and hardens gently, so shells, bones and plant matter survive as fossils.
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