Igneous rocks and metamorphic rocks and their composition

Asked January 28, 2017, 10:27 AM EST

does the metamorphic rocks and igneous rocks contains same composition and why?

Outside United States

1 Response

Good question! To answer your question, rocks and minerals are always recycling. By definition, igneous rocks are solidified from lava or magma through volcanic processes. Metamorphic rocks have been created by extreme pressure and/or heat. The altered rocks were once sedimentary, igneous or other metamorphic rocks.

Your question asks if metamorphic and igneous rocks contain the same composition. The minerals that make up all the rocks have chemical compositions. Depending on what type of rock was altered through the metamorphic process, the rock will contain the original rock's chemical signature. For example, a granite (a type of magma) will alter through the metamorphic process to gneiss.
https://en.wikipedia.org/wiki/Gneiss
The fun part of metamorphosed rocks is that the parent rock texture changes with the pressure and heat. Sometimes new minerals are formed or cool striping emerges as like minerals collect together.
Have fun exploring rocks and minerals!