Seafloor Spreading

Definition

Seafloor spreading is the geological process through which new oceanic crust is formed at mid-ocean ridges and slowly moves away from the ridge, driven by tectonic forces. This phenomenon provides crucial evidence for the theory of plate tectonics and explains how continents can drift over geological time, reshaping Earth's surface.

5 Must Know Facts For Your Next Test

1. Seafloor spreading was first proposed in the early 1960s and gained strong support from evidence gathered during oceanographic expeditions.
2. As magma rises at mid-ocean ridges, it cools and solidifies, forming new oceanic crust that is symmetrically distributed on either side of the ridge.
3. The age of seafloor rocks increases with distance from the mid-ocean ridge, demonstrating the continuous process of seafloor spreading.
4. Seafloor spreading is a key mechanism in the recycling of Earth’s lithosphere, as old oceanic crust can be subducted back into the mantle at convergent plate boundaries.
5. This process plays a significant role in shaping ocean basins and influences global climate patterns by altering ocean currents.

Review Questions

• How does seafloor spreading support the concept of continental drift?
  • Seafloor spreading supports continental drift by providing a mechanism for how continents move apart over time. As new oceanic crust is formed at mid-ocean ridges through seafloor spreading, it pushes older crust away from the ridge. This movement causes the continents on either side of the ocean to drift apart, illustrating that continents are not static but are part of larger tectonic plates that are constantly shifting.
• Discuss how paleomagnetism has contributed to our understanding of seafloor spreading.
  • Paleomagnetism has played a vital role in understanding seafloor spreading by revealing patterns of magnetic reversals recorded in oceanic crust. As magma cools at mid-ocean ridges, iron-rich minerals align with Earth's magnetic field, preserving a record of its orientation. By studying these patterns, scientists can track the age of rocks and demonstrate that new crust is continuously formed at the ridges and moves outward, supporting the theory of plate tectonics.
• Evaluate the implications of seafloor spreading on global geological processes and its effects on Earth’s surface over time.
  • Seafloor spreading has significant implications for global geological processes as it directly influences plate tectonics and reshapes Earth's surface over millions of years. The formation of new oceanic crust contributes to the dynamics of plate boundaries, leading to phenomena such as earthquakes and volcanic eruptions. Additionally, it impacts ocean basin formation and alters sea levels and marine ecosystems. Over time, these processes contribute to continental drift, creating new landforms and influencing climate patterns across the globe.

Related terms

Mid-Ocean Ridge: An underwater mountain range formed by plate tectonics, where seafloor spreading occurs, leading to the creation of new oceanic crust.

Paleomagnetism: The study of the magnetic properties of rocks that helps determine the historical movements of tectonic plates by analyzing changes in Earth's magnetic field recorded in rocks.

Plate Boundaries:

Regions where two tectonic plates meet, leading to various geological activities including earthquakes, volcanic activity, and the formation of mountain ranges.