ICSE Class 7 Answered

Explain: Extrusive Igneous rocks Intrusive Igneous rocks

Asked by Topperlearning User | 13 May, 2015, 07:20: AM

Expert Answer

Extrusive igneous rocks: These rocks are formed due to the solidification of magma which reaches the Earth’s surface through fissures or volcanic eruptions. Since hot magma cools down and solidifies at a faster pace, these rocks are fine grained with a smooth texture. Example: basalt and feldspar.
Intrusive igneous rocks: These rocks are formed when the magma is not able to reach to the surface of the Earth and cools down below the Earth’s surface. Since, magma takes a lot of time to cool beneath the Earth’s surface, intrusive rocks have large crystals and a coarse texture. Examples: granite and diorite.

Answered by | 13 May, 2015, 09:20: AM