Which process in the rock cycle changes existing rocks into metamorphic rocks due to heat and pressure?

Which process in the rock cycle changes existing rocks into metamorphic rocks due to heat and pressure?

• A. Weathering
• B. Erosion
• C. Melting
• D. Metamorphism

Answer: (D)

Heat and pressure acting on rocks inside the Earth's crust can rearrange minerals and form new minerals, changing the rock's texture and structure without melting. This solid-state transformation is metamorphism, and it produces metamorphic rocks such as slate from shale, marble from limestone, and quartzite from sandstone. The key here is that the rock stays solid while its minerals re-crystallize and align under high temperature and pressure. Weathering breaks rocks into smaller pieces at the surface, and erosion moves those pieces around. Melting turns rock into magma, which then crystallizes into igneous rocks. These processes don’t produce metamorphic rocks through heat and pressure in the solid state, which is why metamorphism is the correct concept.

Heat and pressure acting on rocks inside the Earth's crust can rearrange minerals and form new minerals, changing the rock's texture and structure without melting. This solid-state transformation is metamorphism, and it produces metamorphic rocks such as slate from shale, marble from limestone, and quartzite from sandstone. The key here is that the rock stays solid while its minerals re-crystallize and align under high temperature and pressure.

Weathering breaks rocks into smaller pieces at the surface, and erosion moves those pieces around. Melting turns rock into magma, which then crystallizes into igneous rocks. These processes don’t produce metamorphic rocks through heat and pressure in the solid state, which is why metamorphism is the correct concept.