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प्रश्न
Describe the method of formation and characteristics of igneous rock.
उत्तर
Method of formation: When magma in its upward movement cools and turns into solid form it is called igneous rock. The process of cooling and solidification can happen in the earth’s crust or on the surface of the earth. Igneous rocks are classified based on texture. The texture depends upon the size and arrangement of grains or other physical conditions of the materials. If molten material is cooled slowly at great depths, mineral grains may be very large. Sudden cooling (at the surface) results in small and smooth grains. Intermediate conditions of cooling would result in intermediate sizes of grains making up igneous rocks. Granite, gabbro, pegmatite, basalt, volcanic breccia and tuff are some of the examples of igneous rocks.
Features:
- They are made up of solidified lava.
- Liquid lava gets solidified by gradual cooling.
- They are compact.
- They do not have fossils.
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संबंधित प्रश्न
Which one of the following are the two main constituents of granite?
Which one of the following is the salient feature of metamorphic rocks?
Which one of the following is not a sedimentary rock?
What do you mean by rocks?
Name the three major classes of rocks.
What is an igneous rock?
What is meant by sedimentary rock?
Describe the mode of formation of sedimentary rock.
Describe the nature and mode of origin of the chief types of rock at the earth’s crust. How will you distinguish them?
Describe the types of metamorphic rock and how are they formed?
