Igneous rocks are formed from what process?

Igneous rocks are formed from what process?

• A. The cooling and solidification of magma
• B. Cementing of sediment particles
• C. Metamorphism of existing rocks
• D. Precipitation from seawater

Answer: (A)

Igneous rocks form when molten rock cools and solidifies. The molten material, magma, resides underground and crystallizes to make intrusive rocks with coarse grains; if the magma erupts as lava at the surface, rapid cooling produces extrusive rocks with fine grains or glass. The texture reflects cooling rate, while the melt’s composition yields rocks ranging from felsic to mafic. Other rock types come from different processes: cementing sediments makes sedimentary rocks, changing minerals under heat and pressure forms metamorphic rocks, and minerals precipitating from seawater create chemical sedimentary rocks. So the essential idea is that igneous rocks originate from cooling and solidification of molten material.

Igneous rocks form when molten rock cools and solidifies. The molten material, magma, resides underground and crystallizes to make intrusive rocks with coarse grains; if the magma erupts as lava at the surface, rapid cooling produces extrusive rocks with fine grains or glass. The texture reflects cooling rate, while the melt’s composition yields rocks ranging from felsic to mafic. Other rock types come from different processes: cementing sediments makes sedimentary rocks, changing minerals under heat and pressure forms metamorphic rocks, and minerals precipitating from seawater create chemical sedimentary rocks. So the essential idea is that igneous rocks originate from cooling and solidification of molten material.