A BROAD AREA WHERE 2 tectonic plates are colliding is a zone of convergence. An area where plates are moving apart is a zone of divergence. Convection in Earth’s mantle drives the 2 motions. Convergence occurs above descending limbs of convective cells, whereas divergence takes place above cells’ rising limbs. The 2 zones’ geologies are similar in many ways—they both have mountain building, earthquakes, and volcanic eruptions—but their geologies also differ in important ways.