Divergent boundary

Definition

A divergent boundary is a tectonic plate boundary where two plates move apart from each other, creating new crust as magma rises to the surface. This process is primarily associated with seafloor spreading and the formation of mid-ocean ridges, highlighting the dynamic nature of Earth's lithosphere and its role in shaping geological features.

5 Must Know Facts For Your Next Test

1. Divergent boundaries are typically found along mid-ocean ridges, such as the Mid-Atlantic Ridge, where the Eurasian and North American plates are moving apart.
2. As the tectonic plates separate, magma from the mantle rises to fill the gap, which can lead to volcanic activity along these boundaries.
3. Divergent boundaries not only create new oceanic crust but also play a critical role in recycling older crust back into the mantle through subduction at convergent boundaries.
4. The movement at divergent boundaries is generally slow, often only a few centimeters per year, but over geological time scales, this can lead to significant changes in Earth's surface.
5. Rift valleys can form on land when continental plates diverge, as seen in the East African Rift, which represents a continental divergent boundary.

Review Questions

• Explain how divergent boundaries contribute to the formation of new geological features.
  • Divergent boundaries contribute to geological features through the process of seafloor spreading and the creation of mid-ocean ridges. As tectonic plates move apart, magma rises from the mantle to fill the gap, solidifying to form new oceanic crust. This continual creation of crust not only shapes underwater topography but can also result in volcanic islands or rift valleys on land as seen in areas like the East African Rift.
• Discuss the relationship between divergent boundaries and volcanic activity.
  • Divergent boundaries are closely linked to volcanic activity due to the rising magma that occurs when tectonic plates separate. As the plates move apart, pressure decreases, allowing magma from the mantle to rise and create new crust. This process often leads to frequent volcanic eruptions along mid-ocean ridges or rift zones, contributing to the geological landscape and sometimes forming islands or underwater volcanoes.
• Evaluate the long-term geological impact of divergent boundaries on Earth's lithosphere.
  • The long-term impact of divergent boundaries on Earth's lithosphere is significant as they facilitate not only the formation of new oceanic crust but also influence plate tectonics and geological evolution. Over millions of years, the continuous creation of new crust at these boundaries can lead to shifts in continental positions, changes in ocean basin size, and alterations in global climate patterns. Additionally, this process aids in recycling older crust back into the mantle at convergent boundaries, maintaining a dynamic balance within Earth's geological systems.

Related terms

Seafloor Spreading:

The process by which new oceanic crust is created as magma rises at mid-ocean ridges and solidifies, causing the ocean floor to expand.

Mid-Ocean Ridge: An underwater mountain range formed by plate tectonics, where tectonic plates are moving apart and new crust is being created.

Transform Boundary:

A type of plate boundary where two tectonic plates slide past each other horizontally, often leading to earthquakes.