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प्रश्न
How are igneous rocks formed?
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उत्तर
Igneous rocks are formed by the cooling and solidification of molten rock called magma, which lies beneath the earth’s crust. These rocks are crystalline and compact. They do not occur in layers or strata, nor do they contain fossils. The cooling and solidification may take place at some depth within the earth or at the surface. The molten magma that reaches the surface of the earth is called lava. Thus, there are two types of igneous rocks classified on the basis of their place of origin – intrusive rocks, which form at some depth in the earth’s crust and extrusive rocks which form at or near the surface of the earth.
संबंधित प्रश्न
Why is coal hard and chunky?
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A category of rock which is formed by the alteration of the parent rock due to heat and pressure is called: ______________.
Classify the following rocks by selecting the correct option given below:
coal
Explain the structure of the earth’s interior?
Describe the process that leads to exfoliation.
State two characteristics of Basic Igneous Rocks.
Give two examples of sedimentary rocks.
Distinguish between the following:
Sills and Dykes.
Classify the following rock: Rock salt
Classify the following rock: Schist
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The core of the earth occupied by rock in iron and nickel.
Give one word for the following.
Igneous rocks, which contain a high percentage of silica.
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______ rocks are formed by the deposition of shells and skeletons of organism.
What is the basis for the classification of rocks?
Give one term for the following statement:
Sheet like body of igneous rock.
Give one term for the following statement:
Formed by evaporation in saline lakes.
Why fossils are preserved in Sedimentary and not in Igneous rocks?
Which one of the following is the most widespread most and productive category of soil.
Match the following:
| (a) | Igneous | (i) | Magma |
| (b) | Sedimentary | (ii) | Transformation |
| (c) | Metamorphic | (iii) | Gypsum |
| (d) | Molten material | (iv) | Basalt |
| (e) | Rock Cycle | (v) | Marble |
The word Ignis means rock.
The world Igneous is derived from the Latin word ______ meaning ______.
Explain Dynamic Metamorphism.
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.
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.
Match the following.
| A. | Granite | 1. | Bed rock |
| B. | Soil layer | 2. | Plutonic rock |
| C. |
Barren island |
3. | Strip farming |
| D. | Soil conservation | 4. | Active Volcano |
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.
Match the following:
| A. | Basalt | 1. | Anthracite |
| B. | Limestone | 2. | Extrusive igneous |
| C. | Coal | 3. | Metamorphic rock |
| D. | Gneiss | 4. | Sedimentary rock |
