Consider the following statements about rock structure :
- 1. Conglomerates are clastic sedimentary rocks.
- 2. Slate is a non-clastic sedimentary rock.
- 3. Granite is a plutonic igneous rock.
- 4. Basalt is an extrusive igneous rock.
Which of the statements given above are correct ?
1, 2 and 3 only
3 and 4 only
1 and 2 only
1, 3 and 4 only
Answer is Wrong!
Answer is Right!
This question was previously asked in
UPSC CAPF – 2023
Statement 1 is correct: Conglomerates are clastic sedimentary rocks formed by the cementation of rounded gravel, pebbles, and boulders. Clastic rocks are composed of fragments of pre-existing rocks or minerals. Statement 3 is correct: Granite is a common type of felsic intrusive igneous rock. Intrusive igneous rocks are also known as plutonic rocks, forming from magma that cools and solidifies slowly beneath the Earth’s surface. Statement 4 is correct: Basalt is a common type of mafic extrusive igneous rock. Extrusive igneous rocks, also known as volcanic rocks, form from lava that erupts onto the surface and cools rapidly. Statement 2 is incorrect: Slate is a fine-grained, foliated metamorphic rock, formed by the metamorphism of shale or mudstone. It is not a sedimentary rock, and clastic/non-clastic classification applies to sedimentary rocks, not metamorphic rocks.
Rocks are classified into igneous, sedimentary, and metamorphic based on their formation process. Sedimentary rocks can be clastic or non-clastic. Igneous rocks can be intrusive (plutonic) or extrusive (volcanic). Metamorphic rocks are formed by transformation of existing rocks.