Divergent plate boundaries

Definition

Divergent plate boundaries are locations where two tectonic plates move away from each other, leading to the formation of new crust as magma rises from below the Earth's surface. This process is central to understanding seafloor spreading, where new oceanic crust is created at mid-ocean ridges, contributing to the dynamic nature of Earth's lithosphere and shaping ocean basins.

5 Must Know Facts For Your Next Test

1. Divergent plate boundaries are primarily found along mid-ocean ridges, which are the longest mountain ranges in the world and often occur deep underwater.
2. As tectonic plates diverge, the magma that rises to fill the gap cools and solidifies, forming new oceanic crust that expands the ocean floor.
3. Earthquakes can occur at divergent boundaries due to the movement of tectonic plates, although they are usually less intense compared to those at convergent boundaries.
4. The East African Rift is a notable example of a continental rift caused by divergent plate movement, where land is stretching and thinning.
5. Hydrothermal vents are often found at divergent boundaries, releasing heated water rich in minerals, supporting unique ecosystems in the deep ocean.

Review Questions

• How do divergent plate boundaries contribute to the formation of new oceanic crust?
  • Divergent plate boundaries facilitate the creation of new oceanic crust through the process of seafloor spreading. When tectonic plates pull away from each other, magma from beneath the Earth's surface rises to fill the gap. As this magma cools and solidifies, it forms new oceanic crust at mid-ocean ridges, continuously adding material to the ocean floor and reshaping it over time.
• Analyze how divergent plate boundaries differ from convergent plate boundaries in terms of geological features and processes.
  • Divergent plate boundaries involve tectonic plates moving apart, leading to features such as mid-ocean ridges and rift valleys where new crust is formed. In contrast, convergent plate boundaries occur when plates move toward each other, resulting in subduction zones, mountain ranges, and volcanic activity. While divergent boundaries create new landforms, convergent boundaries often lead to the destruction or recycling of existing crust.
• Evaluate the environmental impacts of seafloor spreading at divergent plate boundaries on marine ecosystems.
  • Seafloor spreading at divergent plate boundaries significantly impacts marine ecosystems by creating hydrothermal vents that release nutrient-rich water into the ocean. These vents support unique biological communities adapted to extreme conditions. Additionally, as new oceanic crust forms, it alters habitats and influences ocean circulation patterns. The geological activity associated with divergent boundaries can also lead to shifts in local ecosystems due to changes in seabed topography and water chemistry.

Related terms

Mid-Ocean Ridge: An underwater mountain range formed by the upwelling of magma at divergent plate boundaries, marking the location where new oceanic crust is created.

Seafloor Spreading: The process by which new oceanic crust is formed at divergent boundaries as tectonic plates pull apart, allowing magma to rise and solidify.

Rift Valley: A lowland region that forms where tectonic plates are moving apart on land, creating a valley-like structure.