Evidence for Whole Mantle Convection Driving Cordilleran Tectonics

Deducing mechanisms for advance and retreat of magmatic arcs is fundamental to understanding accretionary tectonics and the evolution of continents. However, first‐order explanations of large spatial and long temporal changes in magmatic arcs remain elusive. We present isotopic evidence that Cordilleran magmatic arc systems were controlled by spherical harmonic degree‐2 mantle convection and characterized by two antipodal upwellings bisected by...