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प्रश्न
How are sedimentary rocks classified?
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उत्तर
Sedimentary rocks are classified into the following types according to the nature of sediments, their origin, composition and the mode of formation.
- Inorganic rocks or Mechanically-formed Sedimentary Rocks :- These type of rocks are formed by the deposition of land derived material. When the river began to flow, they eroded the rocks and washed away to the sea. Clay, shale, sandstone were formed in this way. These rocks are called inorganic rocks.
- Organically formed Sedimentary Rocks :- These rocks are formed by the deposition of plants and sea organisms. Millions of years ago, there grew huge forest in marshy places. In course of ages they were buried underground and the internal heat changed them into coal. Moreover, there are millions and millions of sea-organisms whose skeleton are made of Calcium carbonate derived from sea water. After their death skeleton sink to the bottom of the seas and are formed into lime true and chalk and coal.
- Chemically-formed Sedimentary Rocks :- There rocks are formed by the evaporation of water from solution containing mineral. Various kinds of salts precipitate from waters of shallow desert lakes, where evaporation of the water is rapid. Gypsum is the best example of this kind of rocks. Several nitrates and potash are also chemically formed sedimentary rocks.
संबंधित प्रश्न
Fill in the blank
Sedimentary rocks such as limestone change into ___________.
How are sedimentary rocks formed?
Explain this term associated with rocks: Extrusive Igneous Rocks
State the types of rocks for the formation of which the following process is involved.
Decomposition of organic matter at different stages and over different periods of time.
Classify the igneous rocks on the basis of their place of origin.
Classify the following rock: Marble
Fill in the blanks
The interior layer is the core, which is made up mainly of iron and nickel, and is called ______.
Give one term for the following statement:
It has a definite chemical composition with its own chemical and physical properties.
Give one term for the following statement:
Igneous rocks of deep seated origin.
Give an example of a Plutonic rock.
______ is the kind of metamorphic rock using which Taj Mahal was built.
Chemical sedimentary rocks are found in the beds of reservoirs.
Distinguish between:
Internal Processes and External processes.
Which Soils are formed by the weathering of metamorphic rocks?
Lava comes out from a volcano.
What is thermal metamorphism?
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.
