S4, top: Thermal evolution of the10 mm/yr full rifting velocity model with average sedimentation along with markers (model shown in Figures 2f-j and 3d-g). Grey shading indicates strain rate. Note the development of small scale convection cells. Middle: Evolution of the basement heat flow of markers shown in top panel. Bottom: Evolution of the basement temperature at markers shown in top panel. Note that the horizontal and vertical scale change in the postrift to better show the small scale convection in the top panel.