Mid-Atlantic Ridge

The Mid-Atlantic Ridge is the slow-spreading divergent plate boundary that runs the length of the Atlantic, separating the North and South American plates from the Eurasian and African plates. Its full spreading rate is about 2 to 5 cm/yr, slow enough that a deep axial rift valley 1 to 3 km below the flanking peaks forms along the crest. The ridge surfaces above sea level in Iceland, where the spreading axis is mapped on land. Symmetric magnetic-anomaly stripes on both flanks, first matched here and across other oceans, supplied the Vine-Matthews-Morley confirmation of seafloor spreading.