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प्रश्न
How are sedimentary rocks classified on the basis of their formation?
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उत्तर
There are three types of this type of rocks :
- Mechanically formed rocks : Denudation of rocks by agents of change results in layers of sedimentary rocks by mechanism.
- Chemically formed rocks : These are formed by evaporation of calcarious water and accumulated along lake and lagoon beds, e.g. gypsum and rock salt.
- Organically formed rocks : These are formed by deposition of dead plants and animals e.g. limestone rock (or Calcareous rock) lignite, bituminous and anthracite coal are carbonaceous rocks formed by compression of vegetation under the layers of sedimentary rocks. In the same way petroleum in between the sedimentary rocks is the result of zurasic age dinosaurs e.g. shale rock, containing oil.
संबंधित प्रश्न
Fill in the blank
Granite is an example of intrusive ________ rocks.
Write True or False. Rewrite the false statement correctly :
Sedimentary rocks are formed by the cooling and solidification of molten rock called magma
Classify the following rocks by selecting the correct option given below:
coal
Give one difference between Extrusive igneous and Intrusive igneous rocks.
Give two examples of metamorphic rocks.
State the types of rocks for the formation of which the following process is involved.
Accumulation takes place over long periods of time in seas, lakes and streams.
Classify the igneous rocks on the basis of their place of origin.
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.
The upper part of lithosphere, which is rich in silica and aluminium.
Fill in the blanks
Extrusive rocks are also known as ______ rocks.
Give reasons for the following
Extrusive rocks generally have small crystals.
Give reasons for the following
Man’s habitat is the biosphere and not the lithosphere in the true sense.
______ into slate caused by thermal metamorphism.
What are the characteristics 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
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 |
Match the following.
| A. | Basalt | 1. | Anthracite |
| B. | Limestone | 2. | Extrusive igneous |
| C. | Coal | 3. | Metamorphic rock |
| D. | Gneiss | 4. | Sedimentary rock |
