Seafloor Spreading

Definition

Seafloor spreading is the process by which new oceanic crust is created at mid-ocean ridges as tectonic plates diverge, causing magma to rise and solidify. This phenomenon is a key mechanism in the theory of plate tectonics and explains how continents drift apart over geological time, shaping the ocean floor and influencing geological features such as ridges and trenches.

5 Must Know Facts For Your Next Test

1. Seafloor spreading occurs primarily at mid-ocean ridges, where tectonic plates diverge, allowing magma to rise from the mantle.
2. As new crust is formed, older crust is pushed away from the ridge, leading to the symmetrical pattern of magnetic stripes found on either side of mid-ocean ridges.
3. This process plays a critical role in the rock cycle, as it contributes to the recycling of oceanic and continental crust.
4. Seafloor spreading provides evidence for the theory of plate tectonics, as it explains how continents can move and interact over time.
5. The rate of seafloor spreading can vary, with some ridges producing new crust at rates of several centimeters per year.

Review Questions

• How does seafloor spreading contribute to our understanding of plate tectonics and continental drift?
  • Seafloor spreading is integral to the theory of plate tectonics because it provides a mechanism for how new oceanic crust forms and how continents drift apart. As tectonic plates move away from each other at mid-ocean ridges, magma rises to create new crust, which pushes older crust outward. This process explains not only the creation of ocean basins but also how continents can gradually move over time, supporting the idea of continental drift.
• Discuss the geological features that are formed as a result of seafloor spreading and their significance in understanding Earth's processes.
  • Seafloor spreading leads to the formation of several significant geological features, including mid-ocean ridges, rift valleys, and ocean basins. These features are crucial for understanding Earth's processes because they indicate active plate boundaries where new crust is being generated. Additionally, the symmetrical magnetic stripes found on either side of mid-ocean ridges provide important evidence for the history of Earth's magnetic field reversals and the ages of oceanic crust.
• Evaluate the implications of seafloor spreading on global geological processes and how it influences phenomena like earthquakes and volcanic activity.
  • Seafloor spreading has profound implications for global geological processes by contributing to the dynamic nature of Earth's lithosphere. As tectonic plates diverge, stresses build up along faults, which can lead to earthquakes when released. Moreover, this movement can also cause volcanic activity at mid-ocean ridges and hotspots. Understanding seafloor spreading allows geologists to predict areas of seismic risk and potential volcanic eruptions, helping in disaster preparedness and risk mitigation efforts.

Related terms

Mid-Ocean Ridge: An underwater mountain range formed by plate tectonics where two tectonic plates are moving apart, leading to volcanic activity.

Tectonic Plates: Large sections of the Earth's lithosphere that move and interact at their boundaries, causing geological activity such as earthquakes and volcanic eruptions.

Continental Drift: The gradual movement of continents across the Earth's surface over geological time, driven by the movement of tectonic plates.