What rock type forms when existing rocks are altered by heat and pressure?

What rock type forms when existing rocks are altered by heat and pressure?

• A. Igneous Rock
• B. Sedimentary Rock
• C. Quartzite
• D. Metamorphic Rock

Answer: (D)

Rocks altered by heat and pressure become metamorphic rocks. Metamorphism happens when existing rocks are buried deep or subjected to tectonic forces, causing minerals to recrystallize and the rock’s texture to realign, often creating new minerals and sometimes a layered or foliated structure. This is different from igneous rocks, which form when molten material cools and solidifies, and from sedimentary rocks, which form from weathered and lithified particles at the surface. Quartzite is an example of a metamorphic rock that forms specifically from sandstone under heat and pressure, but the general concept described here is metamorphism producing metamorphic rocks.

Rocks altered by heat and pressure become metamorphic rocks. Metamorphism happens when existing rocks are buried deep or subjected to tectonic forces, causing minerals to recrystallize and the rock’s texture to realign, often creating new minerals and sometimes a layered or foliated structure. This is different from igneous rocks, which form when molten material cools and solidifies, and from sedimentary rocks, which form from weathered and lithified particles at the surface. Quartzite is an example of a metamorphic rock that forms specifically from sandstone under heat and pressure, but the general concept described here is metamorphism producing metamorphic rocks.