Seafloor Spreading

Definition

Seafloor spreading is the process by which new oceanic crust forms at mid-ocean ridges as tectonic plates diverge, causing the ocean floor to expand. This phenomenon is a key mechanism of plate tectonics and plays a crucial role in the formation of geological features such as ridges, trenches, and islands, as well as influencing ocean currents and marine ecosystems.

5 Must Know Facts For Your Next Test

1. Seafloor spreading occurs at mid-ocean ridges, where magma rises from below the Earth's surface and solidifies to form new crust.
2. As tectonic plates move apart, they create a gap that allows magma to escape, pushing older crust away from the ridge.
3. This process not only contributes to the growth of ocean basins but also plays a role in volcanic activity and earthquake formation.
4. The age of oceanic crust increases with distance from mid-ocean ridges, supporting the theory of seafloor spreading.
5. Seafloor spreading helps explain the distribution of various geological features, including island arcs and deep-sea trenches formed by interactions between tectonic plates.

Review Questions

• How does seafloor spreading contribute to the formation of mid-ocean ridges and other geological features?
  • Seafloor spreading is responsible for creating mid-ocean ridges as tectonic plates pull apart. When magma rises from below the Earth’s surface and solidifies at these ridges, it forms new oceanic crust. This process not only results in the formation of mid-ocean ridges but also influences other geological features like deep-sea trenches, which are formed at subduction zones where older crust is recycled back into the mantle.
• Analyze how seafloor spreading affects ocean ecosystems and marine life.
  • Seafloor spreading influences ocean ecosystems by creating unique habitats around mid-ocean ridges. The volcanic activity associated with this process can lead to hydrothermal vents that support diverse marine life, including organisms that rely on chemosynthesis rather than photosynthesis. These vents serve as crucial ecosystems for various species, promoting biodiversity and influencing food webs in deep-sea environments.
• Evaluate the implications of seafloor spreading on global plate tectonics and its connection to natural disasters.
  • Seafloor spreading has significant implications for global plate tectonics as it drives the movement of tectonic plates across the Earth's surface. This movement can lead to geological events such as earthquakes and volcanic eruptions at plate boundaries. Understanding seafloor spreading is essential for predicting these natural disasters, as regions near mid-ocean ridges or subduction zones are often more susceptible to seismic activity and volcanic eruptions due to the dynamic nature of plate interactions.

Related terms

Mid-Ocean Ridge: An underwater mountain range formed by plate tectonics where seafloor spreading occurs, creating new oceanic crust.

Subduction Zone: A region of the Earth where one tectonic plate moves under another, leading to the recycling of oceanic crust back into the mantle.

Plate Tectonics: The theory explaining the movement of Earth's lithospheric plates on the asthenosphere, responsible for many geological phenomena including seafloor spreading.