Ancient Imbalances Sent Earth's Continents "Wandering" Anne Minard for National Geographic NewsApril 7, 2008 A new study lends weight to the controversial theory that Earth became massively imbalanced in the distant past, sending its tectonic plates on a mad dash to even things out. Bernhard Steinberger and Trond Torsvik, of the Geological Survey of Norway, analyzed rock samples dating back 320 million years to hunt for clues in Earth's magnetic field about the history of plate motions. The researchers found evidence of a steady northward continental motion and, during certain time intervals, clockwise and counterclockwise rotations. That pattern matches the...