Civil Engineering - Building Materials - Discussion

Plutonic rock is also a part of igneous rock. Then, why the igneous rock is not a considerable answer.

Plutonic rocks are formed by the cooling of magma at considerable depths from the earth's surface. These rocks are also known as intrusive rocks because they intrude into the existing rock formations. Plutonic rocks are different from volcanic rocks, which are formed due to the cooling of lava on the earth's surface.

The rocks made from the cooling and solidifying of molten rock (magma) are called igneous rocks and the two categories of igneous rocks - are volcanic and plutonic rocks.

Volcanic rocks are found on the earth's surface whereas plutonic rocks are found at a considerable depth from the earth's surface.

Plutonic rocks are coarse-grained crystalline igneous rocks formed by consolidation of molten rock material or magma below the Earth's surface (Latin Pluto, god of the Underworld).

Intrusive=plutonic.

Plutonic rock.

Because of larger depth.

What about Igneous rocks?

Plutonic -> Considerable depth.
Hypabassal -> shallow.
Volcanic -> Surface.

Igneous rocks are formed due to the solidification of molten magma laying below or above the earth's surface.

Extrusive igneous rocks:these rocks are formed due to the solidification of molten magma laying on the surface of earth eg basalt.

Intrusive igneous rocks. Rocks formed due to solidification of molten magma inside the crust.

1. Plutonic igneous rocks: rocks formed at considerable depth e.g granite.
2 Hypabyssal igneous rocks: rocks formed at moderate depth e.g dolerite.

A is the correct answer.

Intrusive, or plutonic, igneous rock forms when magma is trapped deep inside the Earth. Intrusive rocks have a coarse-grained texture. Extrusive Igneous Rocks: Extrusive, or volcanic, igneous rock is produced when magma exits and cools above (or very near) the Earth's surface.