Extrusive (Volcanic) Formations:
* Lava flows: These are the most common formation, where molten lava flows across the landscape and solidifies. The surface texture can be smooth, ropy (pahoehoe), blocky (aa), or with a combination of both.
* Lava tubes: These are tunnels formed when the surface of a lava flow cools and solidifies, while the molten lava continues to flow underneath.
* Lava pillars: These are formed when lava cools and solidifies around a vertical vent or fissure.
* Volcanic cones: These are cone-shaped hills built up by the accumulation of lava flows and pyroclastic material (ash, rocks, and gas) erupted from a central vent.
* Craters: These are bowl-shaped depressions at the top of volcanic cones, formed by the eruption of lava and other materials.
* Calderas: These are large, cauldron-like depressions formed by the collapse of a volcano's summit after a major eruption.
Intrusive (Plutonic) Formations:
* Dikes: These are vertical or near-vertical sheet-like intrusions of magma that cut across existing rock layers.
* Sills: These are horizontal or nearly horizontal intrusions of magma that are injected between existing rock layers.
* Laccoliths: These are mushroom-shaped intrusions that force overlying rock layers upward.
* Batholiths: These are very large, irregularly shaped intrusive bodies of igneous rock that often form the core of mountain ranges.
Other Formations:
* Lava columns: These are tall, vertical formations formed by the cooling and hardening of lava in a columnar structure.
* Lava caves: These are underground cavities formed by the flow of lava through lava tubes.
* Lava bridges: These are arches formed by the cooling and hardening of lava over a stream or other opening.
Specific Textures and Features:
* Columnar jointing: This refers to the formation of vertical, hexagonal columns in basalt lava flows due to cooling and contraction.
* Vesicles: These are gas bubbles trapped in lava as it cools and solidifies.
* Amygdales: These are vesicles that have been filled with secondary minerals, often after the lava has cooled.
* Scoria: This is a type of volcanic rock with a frothy texture, often formed by the rapid cooling of gas-rich lava.
These are just some of the many formations created by cooling lava. The specific formations created will depend on the specific circumstances of the eruption and the surrounding environment.
