ScienceDaily (Oct. 7, 2011) — Rifting is one of the fundamental geological forces that have shaped our planet. Were it not for the stretching of continents and the oceans that filled those newly created basins, Earth would be a far different place. Yet because rifting involves areas deep below Earth's surface, scientists have been unable to understand fully how it occurs.
http://www.sciencedaily.com/releases/2011/10/111006141406.htm