Plate tectonics on the Earth triggered by plume-induced subduction initiation

Abstract

Scientific theories of how subduction and plate tectonics began on Earth--and what the tectonic structure of Earth was before this--remain enigmatic and contentious. Understanding viable scenarios for the onset of subduction and plate tectonics is hampered by the fact that subduction initiation processes must have been markedly different before the onset of global plate tectonics because most present-day subduction initiation mechanisms require acting plate forces and existing zones of lithospheric weakness, which are both consequences of plate tectonics. However, plume-induced subduction initiation could have started the first subduction zone without the help of plate tectonics. Here, we test this mechanism using high-resolution three-dimensional numerical thermomechanical modelling. We demonstrate that three key physical factors combine to trigger self-sustained subduction: (1) a strong, negatively buoyant oceanic lithosphere; (2) focused magmatic weakening and thinning of lithosphere above the plume; and (3) lubrication of the slab interface by hydrated crust. We also show that plume-induced subduction could only have been feasible in the hotter early Earth for old oceanic plates. In contrast, younger plates favoured episodic lithospheric drips rather than self-sustained subduction and global plate tectonics.

Regimes of subduction and lithospheric dynamics in the Precambrian: 3D thermomechanical modelling

“…This geodynamic regime, usually named 'plume tectonics', 'plume-lid tectonics' or 'heatpipe regime', has been previously discussed (Hamilton, 1998;Smithies et al, 2003;Herzberg, 2014) and modelled (Vlaar et al, 1994;Johnson et al, 2014;François et al, 2014;Gerya et al, 2015) by several authors. Van Kranendonk (2011) (Sizova et al, 2015;Gerya et al, 2015).…”

Philippine Sea Plate inception, evolution, and consumption with special emphasis on the early stages of Izu-Bonin-Mariana subduction

“…Ishizuka et al (2013) ruled this hypothesis out considering that the mantle 2 OIB enrichment, which persisted over 15 m.y., has the characteristics of a very depleted mantle and does not show evidence of an enriched plume. Plume-induced subduction initiation has been invoked by Gerya et al (2015) based on a hotter early Earth, but in a colder Earth where plate tectonics is ongoing, one may consider that the basal drag that the plume exerted below the plates might have altered the small proto-PSP motion. (3) Spontaneous subduction involving the vertical sinking of older, denser lithosphere along a transform-fracture system, as proposed by many authors (e.g., Karig 1982;Stern and Bloomer 1992;Shervais and Choi 2011) can also be ruled out.…”

The geology of Cuba: A brief overview and synthesis

“…It has recently been suggested that emplacement of the Galapagos plume head formed most of the Caribbean plate, namely the (Caribbean Large Igneous Complex or "CLIP"), and that CLIP emplacement caused lithospheric collapse and formation of new subduction zones (Gerya et al, 2015), a process termed "plumeinduced subduction initiation" (PISI). These subduction zones are argued to have formed around the plume head, perhaps first around the north at ca.…”

“…An integrated geologic and geodynamic (Gerya et al, 2015) case has been made that Caribbean plate formation began when the Galapagos mantle plume head impinged on the Proto-Caribbean seaway in Early Cretaceous time. Alternatively, Pindell et al (2012) proposed that onset of subduction at ca.…”