Pulsating phenomena can control continental breakup and the formation and closing of oceanic basins. Using a two-dimensional time-dependent convection model with a non-linear, temperature- and depth-dependent rheology, we have obtained self-consistently such types of pulsating behavior. Very hot mantle plumes ascend to the surface, where they can quickly thin the lithosphere down to a few kilometers. An episode of intense shear heating then ensues, which is comparable to the length of the main episode for flood volcanism, lasting a couple of Myrs. The highest plate velocities occur during this period, when both the lithosphere and slab are profusely lubricated by the impingement of the hot plume. ¿ American Geophysical Union 1996