Divergent boundary

Definition

A divergent boundary is a tectonic plate boundary where two plates move away from each other, creating new crust as magma rises to the surface. This process often leads to the formation of rift valleys and oceanic ridges, which can influence various geological and hydrological features, including the creation of lakes in tectonically active regions.

5 Must Know Facts For Your Next Test

1. Divergent boundaries are primarily found along mid-ocean ridges, where they create new oceanic crust as tectonic plates separate.
2. The movement at divergent boundaries can lead to the formation of rift valleys on land, where large cracks develop due to tectonic forces pulling apart the crust.
3. Tectonic lakes often form in areas near divergent boundaries as the land sinks or fractures, creating basins that can fill with water.
4. Seafloor spreading occurs at divergent boundaries, allowing new material from the mantle to rise and solidify, thus expanding ocean basins over time.
5. Volcanic activity is common at divergent boundaries, as magma can easily reach the surface through the cracks created by separating plates.

Review Questions

• How do divergent boundaries contribute to the formation of rift valleys and other geological features?
  • Divergent boundaries create rift valleys when tectonic plates pull apart, causing the land to sink between them. As these plates separate, they can also generate fissures and faults that lead to additional geological features such as volcanic activity. The creation of rift valleys allows for new basins to form, which can eventually develop into lakes as they fill with water.
• Discuss the role of divergent boundaries in seafloor spreading and its impact on oceanic geography.
  • At divergent boundaries, seafloor spreading occurs as tectonic plates move away from each other, allowing magma from the mantle to rise and create new oceanic crust. This process not only shapes the ocean floor by forming mid-ocean ridges but also influences global ocean circulation and marine ecosystems. As new crust forms, it changes the topography of the ocean basins, impacting both geological processes and marine habitats.
• Evaluate how divergent boundaries affect lake formation in tectonically active regions and their significance in local ecosystems.
  • Divergent boundaries significantly influence lake formation by creating depressions in the landscape that can fill with water. These tectonically driven lakes often have unique ecosystems due to their geological origins and can be essential habitats for various species. The characteristics of these lakes, such as water chemistry and temperature variations, are influenced by the underlying geology and volcanic activity associated with divergent boundaries, making them critical for biodiversity in tectonically active areas.

Related terms

Rift Valley: A lowland region formed by the downward displacement of a block of the Earth's crust between two fault lines, typically associated with divergent boundaries.

Mid-Ocean Ridge: An underwater mountain range formed by plate tectonics at divergent boundaries, where new oceanic crust is created as magma rises from the mantle.

Continental Drift: The theory that continents have moved over geological time from a single landmass, contributing to the understanding of divergent boundaries and their effects on landforms.