Figure 1. The state of developed free thermal convection, adopted as an initial moment at which a continent is introduced into the mantle: (a) free mantle convection; (b) mantle convection with the continent. Velocity vectors are shown by arrows; dimensionless temperature is quantified by shades ranging from black (T = 0) to light (T = 1). The upper (a) plots are the inferred relative heat flow distribution (thin curve, left-hand axis) and ocean bottom topography (thick curve, right-hand axis). The upper (b) plot is the relative heat flow distribution.