Divergent plate boundaries

Definition

Divergent plate boundaries are regions where two tectonic plates move away from each other, leading to the creation of new oceanic crust. This process is primarily facilitated by seafloor spreading at mid-ocean ridges, where magma rises to fill the gap between the plates and solidifies, forming new lithosphere. The movement at these boundaries not only results in the formation of new crust but also contributes to the overall evolution and reshaping of the ocean floor.

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 bisects the Atlantic Ocean.
2. As plates pull apart, magma from the mantle rises to create new oceanic crust, resulting in hydrothermal vents that support unique ecosystems.
3. The rate of seafloor spreading at divergent boundaries can vary significantly, typically ranging from a few millimeters to several centimeters per year.
4. Earthquakes and volcanic activity are common at divergent boundaries due to the movement of tectonic plates and the release of pressure in the Earth's crust.
5. Divergent boundaries play a crucial role in the recycling of Earth's crust, helping to balance the processes occurring at convergent plate boundaries where crust is destroyed.

Review Questions

• What processes occur at divergent plate boundaries that lead to the formation of new oceanic crust?
  • At divergent plate boundaries, tectonic plates move away from each other, allowing magma from the mantle to rise up through cracks in the Earth's crust. This magma cools and solidifies upon reaching the ocean water, forming new oceanic crust. The continual movement and separation of these plates contribute to ongoing seafloor spreading, which creates new lithosphere and reshapes the ocean floor.
• How does seafloor spreading impact marine ecosystems found near mid-ocean ridges?
  • Seafloor spreading at divergent plate boundaries leads to the formation of hydrothermal vents, which release mineral-rich water heated by volcanic activity. These vents create unique habitats that support diverse ecosystems reliant on chemosynthesis rather than photosynthesis. Organisms such as tube worms and extremophiles thrive in these environments, showcasing how divergent boundaries can influence biological diversity in marine ecosystems.
• Evaluate the significance of divergent plate boundaries in the context of global tectonic activity and Earth’s geological processes.
  • Divergent plate boundaries are crucial to understanding global tectonic activity as they facilitate the continuous cycle of crust formation and recycling. This process not only contributes to the expansion of ocean basins but also influences geological phenomena such as earthquakes and volcanic eruptions. Furthermore, divergent boundaries impact Earth's climate over geological timescales by influencing ocean circulation patterns and carbon cycling through interactions between tectonic processes and marine ecosystems.

Related terms

Seafloor Spreading:

The process by which new oceanic crust is formed through volcanic activity at mid-ocean ridges as tectonic plates move apart.

Mid-Ocean Ridge: An underwater mountain range formed by plate tectonics, characterized by divergent boundaries where new oceanic crust is generated.

Rift Valley: A lowland region that forms where tectonic plates are moving apart, often associated with continental divergence.