Seafloor spreading

Definition

Seafloor spreading is the geological process where new oceanic crust is formed at mid-ocean ridges and gradually moves away from the ridge, leading to the expansion of ocean basins. This process is a crucial component of plate tectonic theory, providing evidence for how continents shift over time as tectonic plates move. It also highlights the relationship between volcanic activity, earthquakes, and the formation of new seafloor.

5 Must Know Facts For Your Next Test

1. Seafloor spreading occurs at mid-ocean ridges, where magma rises to create new oceanic crust.
2. The age of oceanic crust increases with distance from mid-ocean ridges, providing clear evidence of the ongoing process of seafloor spreading.
3. Seafloor spreading contributes to the movement of tectonic plates and is responsible for the dynamic nature of Earth's surface.
4. The process also generates volcanic activity and earthquakes along mid-ocean ridges as tectonic plates diverge.
5. Evidence from paleomagnetism supports seafloor spreading, showing symmetrical patterns of magnetic stripes on either side of mid-ocean ridges.

Review Questions

• How does seafloor spreading provide evidence for plate tectonic theory?
  • Seafloor spreading supports plate tectonic theory by demonstrating how new oceanic crust is created at mid-ocean ridges and how it pushes older crust away from the ridge. This movement explains how continents can drift apart over time due to the dynamic nature of tectonic plates. Additionally, the symmetrical patterns of magnetic stripes on either side of mid-ocean ridges reveal a historical record that aligns with the concept of plate movement.
• What geological features are directly associated with seafloor spreading, and how do they influence seismic activity?
  • Geological features such as mid-ocean ridges are directly associated with seafloor spreading, serving as sites for new crust formation. As tectonic plates diverge at these ridges, they can lead to increased volcanic activity and earthquakes in surrounding areas. The movement at these boundaries creates tension and release in the Earth's crust, resulting in seismic events that can be measured and studied.
• Evaluate the implications of seafloor spreading on our understanding of Earth's geological history and tectonic processes.
  • Seafloor spreading significantly enhances our understanding of Earth's geological history by providing insights into how continents have shifted over millions of years. It illustrates the mechanisms behind continental drift and offers a framework for studying tectonic processes. This understanding not only helps explain current geological features but also aids in predicting future changes in Earth's surface, allowing scientists to connect past events with present-day tectonic activity.

Related terms

Mid-ocean ridge: An underwater mountain range formed by plate tectonics, where seafloor spreading occurs and new oceanic crust is created.

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

Paleomagnetism: The study of the magnetic properties of rocks, which provides evidence for seafloor spreading by showing the history of magnetic field reversals recorded in oceanic crust.