The Mid-Atlantic Ridge serves as a prime example of a divergent plate boundary in the Atlantic Ocean.
Understanding Divergent Plate Boundaries
Divergent plate boundaries occur where tectonic plates move apart from one another. This separation allows magma from the Earth's mantle to rise and solidify, creating new crustal material. This process is known as seafloor spreading.
The Mid-Atlantic Ridge: A Classic Example
- Location: Running roughly north-south along the center of the Atlantic Ocean basin.
- Process: At the Mid-Atlantic Ridge, the North American Plate and the Eurasian Plate, and the South American Plate and the African Plate are moving apart.
- Result: This divergence allows magma to rise, cool, and solidify, forming new oceanic crust. This continuous process has gradually widened the Atlantic Ocean over millions of years.
- Evidence: The age of the oceanic crust increases with distance from the ridge, providing strong evidence for seafloor spreading. Magnetic anomalies, patterns of alternating magnetic polarity recorded in the ocean floor, further support this process.
Sea-Floor Spreading
Sea-floor spreading is the mechanism driving the creation of new oceanic crust at divergent plate boundaries like the Mid-Atlantic Ridge. As the plates separate, the space is filled with molten rock that cools and solidifies, effectively pushing the older crust away from the ridge.
