Fig. 2. Geodynamic models of rift evolution.

a–g, The sequential migration of Rayleigh–Taylor instabilities along the lithospheric keel, causing convective removal of the TBL (beige). This process, migrating at a rate of 15–20 km Myr⁻¹, drives a ‘wave’ of isostatic uplift and surface denudation that similarly migrates across the craton at a comparable rate, and in some cases, more slowly, reflecting delayed landscape response times. The spatial and temporal extent of this process is limited by the width of the continent. Rift onset occurs 10 Myr before the time step shown in a, with continental break-up and seafloor spreading occurring in time steps c and d, respectively. Note that the reference frame is chosen such that the right continent is fixed, whereas the left continent is moving at 10 mm year⁻¹. Values provided above each image on the left-hand side show timing relative to continental break-up in panel c. The images are adapted from ref. ¹¹, which provides the animation for this reference model. In the simulations (see Supplementary Videos 1–4), the rift-border fault, or proto-escarpment, is 100–300 km from the COB.