Lava

Definition

Lava is molten rock that emerges from a volcano during an eruption and flows across the Earth's surface. When lava cools and solidifies, it forms igneous rock, playing a crucial role in the rock cycle. This process not only creates new landforms but also affects the surrounding environment and ecosystems.

5 Must Know Facts For Your Next Test

1. Lava can vary in temperature, typically ranging from 700 to 1,200 degrees Celsius, depending on its composition.
2. There are different types of lava flows, such as pahoehoe (smooth and ropy) and aa (rough and jagged), which differ based on viscosity.
3. When lava erupts underwater, it can create unique formations called pillow lavas due to rapid cooling.
4. The release of gases during a lava flow can significantly impact local air quality and climate conditions.
5. Lava has the potential to create new landforms such as islands, mountains, and plateaus as it cools and solidifies over time.

Review Questions

• How does the process of lava formation contribute to the rock cycle?
  • Lava formation is a critical part of the rock cycle because it represents the transition of molten rock from beneath the Earth's surface to solid igneous rock on the surface. When a volcano erupts, magma rises and becomes lava upon reaching the surface. As this lava cools and solidifies, it forms new igneous rock, which can later be broken down into sediments through weathering and erosion, eventually forming sedimentary rock. This cycle illustrates how different types of rocks are interconnected.
• Discuss how different types of lava influence volcanic eruption styles and their geological impact.
  • Different types of lava, based on their viscosity and chemical composition, significantly influence volcanic eruption styles. For instance, low-viscosity basaltic lava tends to flow easily, resulting in non-explosive eruptions that produce extensive lava flows. In contrast, more viscous lavas like rhyolitic can trap gas bubbles, leading to explosive eruptions that generate ash clouds and pyroclastic flows. The geological impact varies accordingly; fluid lavas may create wide shield volcanoes while explosive events can form stratovolcanoes and cause widespread destruction.
• Evaluate the long-term environmental effects of lava flows on ecosystems and human settlements.
  • Lava flows can have profound long-term environmental effects on ecosystems and human settlements. Initially, they can devastate areas by burying vegetation, altering landscapes, and destroying infrastructure. However, over time, as lava cools and breaks down into soil, new habitats can form that support diverse plant and animal life. This regeneration process often leads to unique ecological communities developing on volcanic land. For human settlements, while destruction occurs immediately during eruptions, some regions may benefit economically from tourism related to volcanic activity or new land for agriculture once recovery occurs.

Related terms

Magma: Magma is molten rock located beneath the Earth's surface, which can rise to the surface and become lava during volcanic eruptions.

Volcanic Eruption: A volcanic eruption is the expulsion of magma, gases, and ash from a volcano, which can create lava flows and pyroclastic materials.

Igneous Rock: Igneous rock is formed from the cooling and solidification of magma or lava, with two main types: intrusive (from magma) and extrusive (from lava).