How igneous rocks are formed?What are the different types of igneous rocks

Igneous rocks are formed through the cooling and solidification of magma or lava. The process can occur below the surface of the Earth forming intrusive igneous rocks, or on the surface forming extrusive igneous rocks. Here are the steps:

1. Magma Formation: Magma, which is molten rock, is formed when the earth's mantle melts. This can happen due to one or more of three main causes: an increase in temperature, a decrease in pressure, or a change in composition.

2. Magma Ascent: The magma rises through the crust because it is less dense than the surrounding rock. It can either reach the surface of the earth (extrusive) or cool and solidify beneath the earth's surface (intrusive).

3. Cooling and Solidification: When the magma cools and solidifies, igneous rocks are formed. The rate of cooling determines the texture of the igneous rock.

There are two main types of igneous rocks:

1. Intrusive Igneous Rocks: These rocks are formed when magma cools and solidifies beneath the Earth's surface. The slow cooling allows large crystals to form. Examples include granite and gabbro.

2. Extrusive Igneous Rocks: These rocks are formed when lava cools and solidifies on the Earth's surface. The rapid cooling does not allow large crystals to form. Examples include basalt and obsidian.