Earth's crust is formed where tectonic plates rift apart and upwelling magma solidifies. Disparate observations from rifts beneath the oceans and on land provide insights into the dynamics of rifting and opportunities for synthesis.

The global system of Earth’s spreading centres — where tectonic plates separate and new crust is formed from cooling magma — accounts for approximately 80% of magmatic activity on Earth. Virtually all of these spreading centres are found beneath the ocean. Midocean ridges play an important role in the exchange of mass and energy between the solid Earth and its hydrosphere, but because they are vast and remote, it is challenging to unravel their secrets. Analogous to the parable of the blind men who try to describe an elephant based on feeling only its tail or trunk, individual views of rifts, although perhaps true, are incomplete. To understand the entire system requires a synthesis from different perspectives, including results from rifts found above sea level. Three studies in Nature Geoscience suggest that formation of crust at rifts is more complicated than previously thought, and call into question the usefulness of the traditional neat classification of all ridge processes according to spreading rate alone 1–3