Early Earth plume-lid tectonics: A high-resolution 3D numerical modelling approach

Abstract

Geological–geochemical evidence point towards higher mantle potential temperature and a different type of tectonics (global plume-lid tectonics) in the early Earth (>3.2Ga) compared to the present day (global plate tectonics). In order to investigate tectono-magmatic processes associated with plume-lid tectonics and crustal growth under hotter mantle temperature conditions, we conduct a series of 3D high-resolution magmatic-thermomechanical models with the finite-difference code I3ELVIS. No external plate tectonic forces are applied to isolate 3D effects of various plume–lithosphere and crust–mantle interactions. Results of the numerical experiments show two distinct phases in coupled crust–mantle evolution: (1) a longer (80–100Myr) and relatively quiet ‘growth phase’ which is marked by growth of crust and lithosphere, followed by (2) a short (∼20Myr) and catastrophic ‘removal phase’, where unstable parts of the crust and mantle lithosphere are removed by eclogitic dripping and later delamination. This modelling suggests that the early Earth plume-lid tectonic regime followed a pattern of episodic growth and removal also called episodic overturn with a periodicity of ∼100Myr.