Magmatism involves the movement, emplacement, and solidification of molten rock (magma) beneath or onto the Earth's surface. While magmatism didn't directly carve the Grand Canyon, it influenced the landscape in several ways: 

• Intrusive igneous activity: Intrusions of magma deep within the Earth's crust can uplift overlying rock layers, influencing the topography of the region. Intrusive igneous rocks, such as granite, can be exposed through erosion and contribute to the canyon's geological diversity.

• Volcanic activity: Though not directly related to the formation of the Grand Canyon itself, volcanic eruptions in the region deposited layers of volcanic ash and lava flows. These volcanic deposits, interbedded with other sedimentary rocks, contribute to the geological record visible within the canyon walls.

Metamorphism refers to the process of rock transformation under high pressure and temperature conditions without melting. In the case of the Grand Canyon, regional metamorphism affected the rocks before the canyon formed. The rocks in the region were subjected to intense heat and pressure due to tectonic movements, causing them to undergo changes in mineralogy and texture. Metamorphism altered the composition and structure of the rocks, making them more resistant to erosion in some cases, which influenced the formation of the canyon's distinctive cliffs and rock formations.