Fig. 1: Plate-breaking reference model.
The reference model shows the progressive development of a global fracture network in response to displacement-controlled increasing interior pressure (at 0.03 km per million years (Myr)) applied to an 80-km-thick lithosphere. a These spheres show the global surface distribution of minimum principal stress magnitudes through time (negative values denote tensile stress, positive values denote compressive stress). b These spheres show the associated displacement (articulated along a horizontal axis, from left to right through each sphere’s center). In both a and b, surface elements which attain their ultimate tensile strain are displayed as fractures in black. At 20 Myr, the single-plate lithosphere remains macroscopically undamaged. At 30–32 Myr, with sustained interior pressure, cracks initiate and propagate. By 34 Myr, crack coalescence generates features such as triple junctions. By 40 Myr, with the intersection of most major crack systems, the global fracture network is established, dividing the surface of the sphere into plate-like segments. Supplementary Fig. 4 shows this model in greater detail, with sets of 15 spheres extending from 10 to 100 Myr.
