The pioneering mapmaker explains how she and colleagues discovered underwater mountain ranges 40,000 miles long, and helped to prove that the continents move.

“We had this magic key, this magic magnetic profile,” Pitman said. “We were able to date it and eventually use it not only as a tool that proved continental drift but a tool by which we could actually reconstruct the pattern of drift, that is the relative position of the continents, and the actual timing of the separation of the continents.”