Many of the strides made towards finding the rheological requirements of continuum models that exhibit these qualities have been made using two-dimensional 6, 7 and regional scale three-dimensional calculations 8, 9, 10, primarily because the presence of the thinner thermal boundary layers that depend on convective vigour (and are understood to characterize terrestrial mantle convection) are considered a necessary requirement for a relevant model. Surface mobility in mantle convection models is enabled by implementing stress-determined deformation to obtain focussed convergent and divergent boundaries manifested on Earth by subduction and oceanic ridge spreading, respectively. lithosphere) featuring a mosaic of stiff surface caps. 5), a primary objective of numerous modelling studies has been to determine the requirements that result in a mantle surface layer (i.e. Motivated by the observation of relatively aseismic low horizontal strain-rate plate interiors (for example, ref. Given its potential for insight into underlying mantle properties and dynamics, obtaining a surface velocity field that emulates the facets of plate tectonics through the modelling of convection in a momentum-free fluid remains an ongoing aspiration of geodynamic studies 1, 2, 3, 4.

Comparing the similarity in the morphologies of the model plate margins to the Earth’s plate boundaries demonstrates that transform-like offsets are a result of stress induced weakness in the lithosphere owing to passive rupturing. Analogous offset segments do not emerge in the boundaries associated with surface convergence. Implementing a yield-stress that governs the viscosity in the lithosphere, spreading boundaries at the top of a vigorously convecting mantle form as divergent linear segments regularly offset by similar length zones that correlate with a large degree of shear but comparatively minimal divergence.

Here, we present global mantle convection calculations that result in a mobile lithosphere featuring dynamically derived plate boundaries exhibiting a contrasting superficial structure which distinguishes convergence and divergence. By comparison, boundaries associated with subduction exhibit uninterrupted continuity. The presence of offsets, appearing at intervals ranging from 10s to 100s of kilometres, is a distinct characteristic of constructive tectonic plate margins.

Divergent boundary