1. Magma Composition: Mount Erebus erupts relatively low-viscosity, basaltic magma. This low-viscosity magma allows for easier flow and the formation of lava lakes at the surface.
2. CO2 Degassing: As the basaltic magma ascends towards the surface, it undergoes degassing, releasing various gases, including significant amounts of CO2.
3. Gas Bubbles: The CO2 gas forms bubbles within the magma. These bubbles act as tiny "ball bearings," reducing friction between the molten rock particles.
4. Reduced Viscosity: The presence of CO2 bubbles reduces the viscosity of the magma, making it more fluid and easier to flow. This reduction in viscosity allows the magma to spread out and form a pool or lake on the surface.
5. Lava Lake Formation: The combination of low-viscosity magma and the presence of CO2 gas bubbles contributes to the formation of a persistent lava lake at Mount Erebus. The lava flows continuously from the volcano's vents and replenishes the lake, maintaining its presence.
6. Effusive Eruptions: Mount Erebus primarily exhibits effusive eruptions, characterized by the relatively calm and gentle outflow of lava rather than explosive eruptions with ash plumes. This effusive behavior further supports the formation of lava lakes.
It's important to note that while CO2 plays a crucial role in the persistence of lava lakes at Mount Erebus, other factors such as the overall composition of the magma and the volcano's unique environmental conditions also contribute to this phenomenon. Mount Erebus serves as a valuable natural laboratory for studying the influence of CO2 in shaping volcanic activity and understanding the complex processes that occur in volcanic systems.
