Basaltic volcanism

Definition

Basaltic volcanism refers to volcanic activity that primarily produces basalt, a low-viscosity lava that flows easily and results in shield volcanoes and extensive lava flows. This type of volcanism is closely associated with divergent plate boundaries, where tectonic plates move apart, allowing magma to rise and erupt at the surface, often creating new oceanic crust.

5 Must Know Facts For Your Next Test

1. Basaltic volcanism occurs at mid-ocean ridges and rift zones, where tectonic plates are moving apart, allowing magma to reach the surface easily.
2. The lava produced in basaltic volcanism is typically low in silica content, which contributes to its fluidity and results in less explosive eruptions compared to other volcanic types.
3. As the lava flows from basaltic eruptions cools, it can form unique geological features such as pillow lavas, which occur when lava erupts underwater.
4. Basaltic volcanism is responsible for the formation of the ocean floor, contributing to the creation of new oceanic crust as magma solidifies upon eruption.
5. Countries with significant basaltic volcanic activity include Iceland and Hawaii, known for their dramatic landscapes shaped by continuous lava flows and shield volcanoes.

Review Questions

• How does basaltic volcanism differ from other types of volcanic activity in terms of eruption style and lava composition?
  • Basaltic volcanism is characterized by low-viscosity lava that is rich in iron and magnesium but low in silica. This results in less explosive eruptions compared to more viscous lavas associated with other types of volcanism, such as rhyolitic or andesitic. The fluid nature of basalt allows it to flow easily over large distances, forming broad shield volcanoes rather than steep stratovolcanoes typical of more explosive eruptions.
• Discuss the significance of mid-ocean ridges in relation to basaltic volcanism and plate tectonics.
  • Mid-ocean ridges are crucial for understanding basaltic volcanism as they represent divergent plate boundaries where tectonic plates are pulling apart. This movement creates a pathway for magma to ascend from the mantle and erupt at the surface. The continuous volcanic activity at these ridges not only produces vast amounts of basaltic lava but also contributes to the formation of new oceanic crust, playing a vital role in the dynamic processes of plate tectonics.
• Evaluate the environmental impacts of basaltic volcanism on coastal ecosystems and human settlements.
  • Basaltic volcanism can significantly impact coastal ecosystems by creating new landforms such as islands and altering habitats through lava flows. While these eruptions tend to be less destructive than more explosive volcanic events, they can still disrupt local wildlife and vegetation. Additionally, human settlements near basaltic volcanoes must prepare for potential lava flows that can threaten infrastructure. However, the creation of new land can also provide opportunities for agriculture and tourism once the areas stabilize.

Related terms

Divergent Plate Boundaries: Locations where tectonic plates move apart, leading to the upwelling of magma from the mantle and resulting in volcanic activity and the formation of new crust.

Shield Volcanoes: Broad, gently sloping volcanoes formed by the eruption of low-viscosity basaltic lava that can travel long distances, resulting in large, expansive landforms.

Pahoehoe Lava: A type of basaltic lava characterized by its smooth, ropy surface, which forms when lava flows slowly and cools gradually.