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प्रश्न
How are sedimentary rocks formed?
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उत्तर
Sedimentary rocks are formed from sediments accumulated over long periods, usually underwater on the floors of shallow seas, rivers, and lakes. These rocks are non-crystalline and are found in layers or strata and contain fossils. Conglomerate, sandstone, limestone, chalk, calcite, and dolomite are examples of sedimentary rocks. Sedimentary rocks are divided into various types depending on how they are formed.
- Mechanically formed sedimentary rocks :
These rocks have been formed by the accumulation of materials derived from other rocks which have been cemented together.
Examples – conglomerate (rounded fragments), breccia (angular fragments). - Organically formed sedimentary rocks :
These rocks have been formed by the accumulation of the remains of living organisms.
Examples – calcareous rocks such as limestone and chalk. - Chemically formed sedimentary rocks:
These rocks have been commonly formed by the process of evaporation of water containing salts in solution.
Examples – rock salt, gypsum, potash, nitrates, calcite, and dolomite.
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संबंधित प्रश्न
Fill in the blank
A category of rock which is formed by the alteration of the parent rock due to heat and pressure is called: ______________.
Write True or False. Rewrite the false statement correctly :
Minerals are organic substances.
Name any two characteristics of Igneous Rocks.
Name the three stages of lithification of Sedimentary rocks.
Explain this term associated with rocks: Extrusive Igneous Rocks
Give one term for the following statement:
Sheet like body of igneous rock.
Give one term for the following statement:
Rounded or sub-rounded fragments, usually water-born cobbles, pebble and gravel, cemented together by a matrix of calcium carbonate, silica, etc.
An aggregate of minerals on the Earth’s Crust is called ______.
Explain about Petrology.
Minerals exist in nature ¡n the form of ______ or ______.
