Igneous rocks are formed by the cooling, solidification, and crystallisation of molten magma either beneath the surface or on the surface of the Earth. When magma cools slowly beneath the surface, it forms intrusive igneous rocks with large crystals. When it erupts and cools quickly on the surface as lava, it forms extrusive igneous rocks with fine grains.
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प्रश्न
Describe how igneous rocks are formed.
लघु उत्तरीय
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उत्तर
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Rock and it's Types
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अध्याय 6: Rocks - EXERCISES [पृष्ठ ६४]
APPEARS IN
संबंधित प्रश्न
What are metamorphic rocks?
State two points of distinction between rocks and minerals.
Distinguish between the following:
Calcarious and Carbonacious rocks.
Differentiate between Rock and Mineral
What is meant by the term ‘metamorphism’?
Classify the following rock: Rock salt
Give one word for the following.
Rocks formed by the cooling and solidification of molten rock from beneath the earth crust.
Give one word for the following.
Igneous rocks, which contain a low percentage of silica.
Give one example of an area of: Metamorphic rocks,
How are sedimentary rocks classified?
Give one term for the following statement:
Formed when mud layers compacted under great pressure composing 80% of this rock.
Igneous rocks are called primary rocks.
Igneous rocks are found in the regions of volcanoes.
What are the uses of soil?
What is thermal metamorphism?
Explain the different types of sedimentary rocks.
Statement (1): Sedimentary rocks consist of many layers.
Statement (2): Sedimentary rocks are formed by the sediments deposited at different points of time.
Match the following.
| A. | Basalt | 1. | Anthracite |
| B. | Limestone | 2. | Extrusive igneous |
| C. | Coal | 3. | Metamorphic rock |
| D. | Gneiss | 4. | Sedimentary rock |
Statement (1): Sedimentary rocks consist of many layers.
Statement (2): Sedimentary rocks are formed by the sediments deposited at different points of time.
Statement (1): Sedimentary rocks consist of many layers.
Statement (2): Sedimentary rocks are formed by the sediments deposited at different points of time.
