Divergent boundaries

Definition

Divergent boundaries are tectonic plate boundaries where two plates move away from each other, creating new crust as magma rises to the surface. This process leads to geological features such as mid-ocean ridges and rift valleys, and plays a significant role in the occurrence of earthquakes in these regions as stress builds up when plates shift apart.

5 Must Know Facts For Your Next Test

1. Divergent boundaries are most commonly found along mid-ocean ridges, where they form new oceanic crust as tectonic plates pull apart.
2. The process of seafloor spreading occurs at divergent boundaries, allowing new material from the mantle to rise and solidify, which contributes to the expansion of ocean basins.
3. As tectonic plates separate at divergent boundaries, small to moderate earthquakes can occur due to the tension and stress that builds as the crust fractures.
4. The East African Rift is an example of a continental divergent boundary that is creating rift valleys, showcasing how these boundaries can also occur on land.
5. Volcanic activity is often associated with divergent boundaries, particularly at mid-ocean ridges where magma rises to fill the gap left by separating plates.

Review Questions

• How do divergent boundaries contribute to the formation of geological features such as mid-ocean ridges and rift valleys?
  • Divergent boundaries contribute to geological features like mid-ocean ridges and rift valleys by allowing tectonic plates to move apart. As the plates separate, magma rises from below the Earth's surface to fill the gap, solidifying and creating new crust. In oceanic regions, this process forms mid-ocean ridges, while on continental land, it can create rift valleys where the land sinks due to tectonic activity.
• Discuss the relationship between divergent boundaries and earthquake activity, highlighting how stress influences seismic events.
  • At divergent boundaries, as tectonic plates pull away from each other, tension builds up due to friction along the fault lines. This stress can lead to sudden releases of energy when the rocks break or slip, resulting in earthquakes. These seismic events can vary in magnitude but are generally smaller compared to those at convergent boundaries due to the nature of plate movement at divergence.
• Evaluate the significance of divergent boundaries in understanding plate tectonics and their impact on Earth’s geological processes.
  • Divergent boundaries are crucial for understanding plate tectonics as they illustrate how new crust is formed and how continents can slowly drift apart over geological time. The process of seafloor spreading at mid-ocean ridges not only helps explain the age of oceanic crust but also influences global sea levels and climate patterns. By studying these boundaries, scientists gain insight into volcanic activity, earthquake distribution, and the dynamic nature of Earth's lithosphere.

Related terms

mid-ocean ridge:

An underwater mountain range formed by the upwelling of magma at divergent boundaries, where new oceanic crust is created.

rift valley:

A lowland region formed by the sinking of land between two divergent tectonic plates, often associated with volcanic activity.

transform boundary:

A type of tectonic boundary where two plates slide past each other horizontally, causing friction and leading to earthquakes.