THERMOMECHANICAL MODELING OF PULSATION TECTONICS AND CONSEQUENCES ON LITHOSPHERIC DYNAMICS

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 r heology, we have obtained self-consistently such types of pulsating be havior. Very hot mantle plumes ascend to the surface, where they can q uickly thin the lithosphere down to a few kilometers. An episode Of in tense shear heating then ensues, which is comparable to the length of the main episode for flood volcanism, lasting a couple of Myrs. The hi ghest plate velocities occur during this period, when both the lithosp here and slab are profusely lubricated by the impingement of the hot p lume.