Which of the following processes does NOT lead to the formation of metamorphic rocks?

The process that does not lead to the formation of metamorphic rocks is cooling. Metamorphic rocks are created through the transformation of existing rocks (either igneous, sedimentary, or other metamorphic rocks) due to high heat and pressure over long periods of time. This process causes changes in the mineral composition and structure of the rock.

Cooling, on the other hand, is primarily associated with the formation of igneous rocks, which occur when molten rock material (magma or lava) cools and solidifies. In contrast, metamorphic processes involve existing rocks undergoing physical and chemical changes without melting. Therefore, cooling is not a factor that contributes to the creation of metamorphic rocks, making it the correct answer in this context.