Which rock type is formed under intense heat and pressure from existing rocks?

Which rock type is formed under intense heat and pressure from existing rocks?

• A. Metamorphic rock
• B. Sedimentary rock
• C. Igneous rock
• D. Weathered rock

Answer: (A)

Rocks transformed by intense heat and pressure are metamorphic rocks. When existing rocks are buried deep in the crust or squeezed by tectonic forces, their mineral grains reorganize and recrystallize, forming new textures and sometimes new minerals without melting. This change happens specifically under high temperature and pressure, which sets metamorphic rocks apart from others formed by different processes. Igneous rocks form when rock melts and then cools into a solid, either underground as intrusive rocks or on the surface as extrusive rocks. Sedimentary rocks form from bits of weathered material that are transported, deposited, and cemented together over time. Weathered rock describes rock that has been worn down by weathering; it’s not itself a rock-forming category like metamorphic, igneous, or sedimentary, though weathering can lead to sediment that may eventually become sedimentary rock. So, the reason metamorphic rock is the best fit is that it specifically describes rocks that have been reshaped by heat and pressure deep in the Earth, without melting.

Rocks transformed by intense heat and pressure are metamorphic rocks. When existing rocks are buried deep in the crust or squeezed by tectonic forces, their mineral grains reorganize and recrystallize, forming new textures and sometimes new minerals without melting. This change happens specifically under high temperature and pressure, which sets metamorphic rocks apart from others formed by different processes.

Igneous rocks form when rock melts and then cools into a solid, either underground as intrusive rocks or on the surface as extrusive rocks. Sedimentary rocks form from bits of weathered material that are transported, deposited, and cemented together over time. Weathered rock describes rock that has been worn down by weathering; it’s not itself a rock-forming category like metamorphic, igneous, or sedimentary, though weathering can lead to sediment that may eventually become sedimentary rock.

So, the reason metamorphic rock is the best fit is that it specifically describes rocks that have been reshaped by heat and pressure deep in the Earth, without melting.