Seafloor Spreading

Definition

Seafloor spreading is the process by which new oceanic crust is formed at mid-ocean ridges as magma rises from beneath the Earth's mantle and cools. This process contributes to the movement of tectonic plates and plays a crucial role in shaping the Earth's surface through geological processes such as volcanic activity and earthquakes.

5 Must Know Facts For Your Next Test

1. Seafloor spreading was first proposed by Harry Hess in the 1960s, providing evidence for the theory of plate tectonics.
2. As new crust forms at mid-ocean ridges, older crust is pushed away from the ridge, causing the ocean floor to gradually expand.
3. The age of oceanic crust increases with distance from mid-ocean ridges, indicating ongoing seafloor spreading over millions of years.
4. Seafloor spreading is responsible for creating new oceanic features such as ridges, valleys, and hydrothermal vents.
5. The process also impacts global climate and sea levels by influencing ocean currents and the distribution of heat across the planet.

Review Questions

• How does seafloor spreading contribute to the theory of plate tectonics and shape the Earth's surface?
  • Seafloor spreading provides crucial evidence for the theory of plate tectonics by demonstrating how oceanic crust is generated at mid-ocean ridges. As tectonic plates move apart, magma rises to fill the gap, forming new crust. This continual creation and movement of crust not only leads to the expansion of ocean basins but also influences geological features like mountains and trenches, ultimately shaping the Earth's landscape.
• Discuss the relationship between seafloor spreading and subduction zones, including their roles in plate tectonics.
  • Seafloor spreading and subduction zones are interconnected processes within plate tectonics. While seafloor spreading occurs at mid-ocean ridges where new crust is created, subduction zones are locations where older crust is recycled back into the mantle. The interaction between these two processes helps maintain balance in Earth's lithosphere; as new crust forms at ridges, older crust must be removed through subduction, preventing continuous growth of the Earth's surface.
• Evaluate how seafloor spreading influences oceanic features and global geological processes over time.
  • Seafloor spreading significantly influences oceanic features such as mid-ocean ridges, deep-sea trenches, and hydrothermal vents. Over time, this process affects not only the geography of ocean basins but also global geological processes like volcanic activity and earthquake frequency. As new crust is formed and old crust is recycled, it creates dynamic systems that affect marine ecosystems, ocean currents, and even climate patterns, illustrating how interconnected these geological processes are.

Related terms

Mid-Ocean Ridge: An underwater mountain range formed by plate tectonics, where seafloor spreading occurs as tectonic plates pull apart.

Subduction Zone: An area where one tectonic plate moves under another and is forced into the mantle, often leading to volcanic activity and earthquakes.

Tectonic Plates: Massive slabs of the Earth's lithosphere that fit together like a jigsaw puzzle, constantly moving and interacting at their boundaries.