How do magma and lava create new crust at the Mid-Atlantic Ridge?

The Mid-Atlantic Ridge is a divergent plate boundary where the Atlantic Ocean floor is actively widening through a process known as seafloor spreading.12

New crust is created through the following geological mechanism:

• Magma Upwelling: As tectonic plates move apart, the reduction in pressure allows magma from the Earth’s mantle to rise and well up into the rift zone along the ridge’s axis.132
• Plumbing System: This molten rock travels through a network of vertical fractures known as sheeted dikes, which serve as the primary conduits transporting magma toward the seafloor.4
• Cooling and Solidification: Upon reaching the surface, the basaltic magma erupts as lava, forming features such as pillow lavas or sheet flows that solidify to create new oceanic crust.34
• Crustal Formation: Beneath the surface, pockets of magma—often referred to as magma chambers—cool slowly to form gabbro, which constitutes the deeper layers of the newly formed crust.4

This continuous cycle of rifting, volcanic activity, and cooling pushes older crustal material away from the ridge, resulting in a seafloor that is progressively younger near the center of the ridge.152