When a landscape is exposed only to energy from Earth's interior, the new rock formations primarily include igneous rocks, which form from the cooling and solidification of molten rock (magma or lava). Basalt is a common dark- colored, fine-grained igneous rock formed from lava flows. Additionally, metamorphic rocks can form when existing rocks are subjected to high temperatures and pressures from Earth's interior, leading to recrystallization and new mineral formation without melting. Examples include hornfels formed by contact metamorphism near magma intrusions and other metamorphic rocks produced by regional metamorphism under great depth and heat. In summary, the prominent new rock formations from Earth's interior energy exposure are:
- Igneous rocks, such as basalt from cooled lava
- Metamorphic rocks formed by heat and pressure, including hornfels
These processes reflect the internal heat engine of the Earth driving the rock cycle and new rock formation through melting, crystallization, and recrystallization.