Changes

Sometimes sedimentary and igneous rocks are subject to pressures so intense or heat so high that they are completely changed. They become metamorphic rocks, which form while buried within the Earth's crust. The process of metamorphism does not melt the rocks, but instead transforms them into denser, more compact rocks. (Barker, 1997) <ref>[http://vulcan.wr.usgs.gov/Glossary/volcano_terminology.html Glossary of Volcano and Related Terminology]</ref>

Sometimes sedimentary and [[igneous rock]]s are subject to pressures so intense or heat so high that they are completely changed. They become '''metamorphic rocks''', which form while buried within the Earth's crust. The process of metamorphism does not melt the rocks, but instead transforms them into denser, more compact rocks. (Barker, 1997) <ref>[http://vulcan.wr.usgs.gov/Glossary/volcano_terminology.html Glossary of Volcano and Related Terminology]</ref>

==References==

==References==