Which type of rock undergoes transformation due to heat and pressure?

Metamorphic rocks are formed through the processes of metamorphism, which involves the transformation of existing rock types—specifically sedimentary rocks, igneous rocks, or other metamorphic rocks—due to intense heat and pressure over geological time. This transformation can cause changes in the mineral composition and structure of the rock, leading to the formation of new minerals and textures that are characteristic of metamorphic rocks.

For instance, limestone, a sedimentary rock, can transform into marble when subjected to high temperatures and pressures. Similarly, shale, another sedimentary rock, may become schist or slate under the right conditions.

The other types of rocks mentioned do not directly undergo this process. Sedimentary rocks form from the accumulation of sediment, often in water, and typically do not change due to heat and pressure. Igneous rocks are formed from the solidification of molten magma or lava, and while they can eventually transform into metamorphic rocks under heat and pressure, they are not transformed by these conditions themselves. Volcanic rocks are a specific subset of igneous rocks that are formed from lava that cools and solidifies on the Earth's surface, and like other igneous rocks, they do not undergo transformation due to heat and pressure in