Basic Geology/Glossary

This is an incomplete list of geological terminology with brief explanations of each concept.

• Andesite: Viscous lava erupted from a volcano above a subduction zone.
• Igneous Rock: A rock produced by the crystallization of magma.
• Geology: The study of Earth's physical structure and the processes that act on it.
• Lahar: River of mud, ash, and water.
• Metamorphic Rock: A rock that has experienced intense temperature and/or pressure after its formation and has changed its composition and/or texture.
• Mineral: A naturally occurring solid inorganic substance with a distinct crystal structure.
• Pahoehoe: Lava with an undulating surface, may have a ropey appearance.
• Rift Valley: A gap between the continental crust marked by volcanism; rift valleys may eventually develop into oceans, seas, etc.
• Rock: A natural material composed of minerals.
• Sedimentary Rock: A rock that has been formed by the lithification of sediment but has not been metamorphosed.
• Subduction zone: Area where plates meet, and one slides beneath the other.
• Texture: The physical appearance of a rock.