Modeled displacement (top), thermal evolution (middle) and velocity (bottom) of three material points, located initially at depths equal to −44 km (red), −40 km (blue), and −38 km (green), during the evolution of the 3D numerical experiment. The first accelerated motion is recorded after ca. 2 Myr of heating and corresponds to downward motion of the blue marker, concomitant with upward motion of the green marker, which corresponds to the onset of the buoyancy-driven segregation. Just before 2.5 Myr, the onset of composition-driven diapirism is marked by rapid motion of all markers, some going up (red and blue points), and others going down (green) at a velocity up to 15 cm/yr. A second rapid, gravitational destabilization of the layers occurs at 5 Myr. From this time onward, the three markers record cycles of temperature increase and decrease from 650 to 900 °C with a period of 1 to 3 Myr, and at a velocity of 1 to 7 cm/yr.