Divergent plate boundary

Definition

A divergent plate boundary is a tectonic setting where two lithospheric plates move apart from each other, leading to the formation of new crust as magma rises to the surface. This process often results in volcanic activity and the creation of mid-ocean ridges, which play a significant role in the Earth's geological activity and landscape.

5 Must Know Facts For Your Next Test

1. Divergent plate boundaries are commonly found along mid-ocean ridges, where two tectonic plates are pulling apart.
2. The movement at divergent boundaries allows magma to rise and solidify, creating new oceanic crust over time.
3. Volcanic eruptions at divergent boundaries are typically less explosive than those at convergent boundaries due to the lower viscosity of the magma.
4. The East African Rift is an example of a divergent boundary on land, showcasing how rifting can lead to the formation of rift valleys.
5. As tectonic plates diverge, they can also cause earthquakes as stress builds up along faults, which release energy when plates slip.

Review Questions

• How do divergent plate boundaries contribute to volcanic activity and the formation of new land?
  • Divergent plate boundaries contribute to volcanic activity as magma rises from the mantle to fill the gap created when two lithospheric plates pull apart. This process not only leads to the formation of new oceanic crust but also results in volcanic eruptions that create features like mid-ocean ridges. As the magma cools and solidifies, it builds up underwater mountains that can eventually emerge above sea level, forming new landmasses.
• Compare and contrast divergent plate boundaries with convergent plate boundaries in terms of geological features and volcanic activity.
  • Divergent plate boundaries are characterized by plates moving apart, leading to new crust formation and typically less explosive volcanic activity. In contrast, convergent plate boundaries involve plates colliding, resulting in subduction zones where one plate is forced beneath another. This often produces more explosive volcanoes and mountain ranges. Both types of boundaries shape the Earth's landscape but do so through different mechanisms and geological processes.
• Evaluate the impact of seafloor spreading at divergent plate boundaries on global ocean circulation and climate.
  • Seafloor spreading at divergent plate boundaries significantly impacts global ocean circulation by creating new ocean floor and influencing water movement patterns. As hot magma rises and cools at mid-ocean ridges, it contributes to the formation of new crust that affects oceanic topography. This topography can alter currents, which play a vital role in regulating climate by distributing heat around the planet. Understanding this connection highlights how geological processes at divergent boundaries not only reshape the Earth but also influence broader environmental systems.

Related terms

Mid-ocean ridge: An underwater mountain range formed by plate tectonics, where new oceanic crust is created as magma rises at divergent boundaries.

Rift valley: A lowland region formed by the sinking of land between two divergent tectonic plates, often characterized by volcanic activity.

Seafloor spreading: The process by which new oceanic crust is created at mid-ocean ridges and gradually moves away from the ridge, resulting in the widening of ocean basins.