Divergent Plate Boundaries

Definition

Divergent plate boundaries are regions where two tectonic plates are moving apart from each other, leading to the formation of new oceanic crust as magma rises to the surface. These boundaries play a crucial role in the process of seafloor spreading and are often associated with mid-ocean ridges, where volcanic activity occurs. The movements at these boundaries not only shape the geological landscape but also influence various volcanic and tectonic processes across the solar system.

5 Must Know Facts For Your Next Test

1. Divergent plate boundaries are primarily located along mid-ocean ridges, such as the Mid-Atlantic Ridge, which is the longest mountain range in the world.
2. At these boundaries, the tectonic plates move apart at rates typically ranging from 1 to 10 centimeters per year, contributing to the gradual expansion of ocean basins.
3. As magma rises to fill the gap created by diverging plates, it cools and solidifies to form new oceanic crust, which is younger than the crust farther away from the ridge.
4. Earthquakes that occur at divergent boundaries are usually shallow and less intense compared to those at convergent boundaries due to the nature of tectonic movement.
5. Divergent boundaries can also be found on land, such as in the East African Rift, where tectonic forces are pulling apart continental crust.

Review Questions

• How do divergent plate boundaries contribute to the formation of new oceanic crust?
  • Divergent plate boundaries contribute to the formation of new oceanic crust through the process of seafloor spreading. As two tectonic plates pull apart, magma from below rises to fill the gap created by this movement. When this magma reaches the surface, it cools and solidifies, creating new oceanic crust that adds to the existing seafloor. This ongoing process is crucial for maintaining the dynamic nature of Earth's geology.
• Discuss how mid-ocean ridges serve as key features of divergent plate boundaries and their role in global tectonics.
  • Mid-ocean ridges are significant features of divergent plate boundaries, acting as underwater mountain ranges formed by upwelling magma. These ridges mark the location where tectonic plates separate and provide a source for new oceanic crust. The activity at mid-ocean ridges is integral to global tectonics as it facilitates seafloor spreading and contributes to plate movement. This process also influences ocean currents and climate over geological time scales.
• Evaluate how divergent plate boundaries can affect volcanic activity across different celestial bodies in our solar system.
  • Divergent plate boundaries play a critical role in volcanic activity not only on Earth but also on other celestial bodies in our solar system. For example, on Mars, the presence of rift valleys suggests similar tectonic processes that may have led to volcanic activity in its past. Moreover, icy moons like Europa exhibit potential signs of a subsurface ocean and possible divergence in their ice crusts, hinting at volcanic processes driven by tidal heating. Understanding these dynamics at divergent boundaries expands our knowledge of geological activity beyond our planet and informs us about potential habitability elsewhere.

Related terms

Seafloor Spreading: The process by which new oceanic crust is created at divergent plate boundaries as tectonic plates move apart.

Mid-Ocean Ridge: An underwater mountain range formed by the upwelling of magma at divergent plate boundaries.

Volcanism: The eruption of magma from beneath the Earth's crust, often occurring at divergent boundaries where tectonic plates separate.