The Mid-Atlantic Ridge sways rather regularly throughout the N-Atlantic sea bottom. The two large convection rolls which must be found at each side of it, can not make jumps or sway irregularly, becuse it is composed of flowing mantle. It must therefore be shaped according to the Earth’s radius and in coherence with the rotation of the Earth.
The crossing between mantle division line of the large cells and the Mid-Atlantic Ridge is found at 32°N, which is where the mantle rolls division line is exactly oriented NS.
The magma flow therefore tends to find its way west of the central line in southern latitudes, but east of it north of 32°N. Then it follows the middle line closely along the Reykjanes Ridge, following the next upwelling line east of the main line.
Again, at equator, the two lines merge into one.