Question

How volcanic rocks form?​

Answer 1

It is formed by the cooling of molten magma on the earth’s surface.

The magma can be derived from partial melts of existing rocks in either a planet's mantle or crust. Typically, the melting is caused by one or more of three processes: an increase in temperature, a decrease in pressure, or a change in composition. Solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive rocks. Igneous rock may form with crystallization to form granular, crystalline rocks, or without crystallization to form natural glasses.

Igneous rocks occur in a wide range of geological settings: shields, platforms, orogens, basins, large igneous provinces, extended crust and oceanic crust.

Answer 2

When magmas reach the Earth's surface and cool and crystallize in subaerial or subaquatic conditions, the resulting rocks are called extrusive or volcanic. Igneous rocks are made up of minerals from the silicate group.

What are igneous rocks?

Igneous or magmatic rocks are those that form when magma cools and solidifies.

If cooling occurs slowly below the surface, rocks with large crystals called plutonic or intrusive rocks are formed, while if cooling occurs rapidly above the surface