Viscous cycle: Quartz is key to plate tectonics

ScienceDaily (2011-03-16) -- More than 40 years ago, pioneering tectonic geophysicist J. Tuzo Wilson described how ocean basins opened and closed along North America's eastern seaboard. His observations, dubbed "The Wilson Tectonic Cycle," suggested the process occurred many times during Earth's long history, most recently causing the giant supercontinent Pangaea to split into today's seven continents. Now, new findings shed surprising light on these restless rock cycles.