Supercontinents, mantle dynamics and plate tectonics: A perspective based on conceptual vs. numerical models

• Published in: Earth-science reviews 2011-03, Vol.105 (1), p.1-24
• Main Authors: Yoshida, Masaki, Santosh, M.
• Format: Article
• Language: English
• Subjects: Assembly; Breakup; Continental dynamics; Convection; Crusts; Dispersing; drainage water; Earth; fuels; insulating materials; Mantle; mantle dynamics; Mathematical models; melting; Numerical analysis; numerical model; Plate tectonics; Plumes; Seismology; supercontinent cycle; supercontinents; tectonics; temperature; Wilson Cycle
• ISSN: 0012-8252; 1872-6828
• DOI: 10.1016/j.earscirev.2010.12.002

The periodic assembly and dispersal of supercontinents through the history of the Earth had considerable impact on mantle dynamics and surface processes. Here we synthesize some of the conceptual models on supercontinent amalgamation and disruption and combine it with recent information from numerical studies to provide a unified approach in understanding Wilson Cycle and supercontinent cycle. Plate tectonic models predict that superdownwelling along multiple subduction zones might provide an effective mechanism to pull together dispersed continental fragments into a closely packed assembly. The recycled subducted material that accumulates at the mantle transition zone and sinks down into the core–mantle boundary (CMB) provides the potential fuel for the generation of plumes and superplumes which ultimately fragment the supercontinent. Geological evidence related to the disruption of two major supercontinents (Columbia and Gondwana) attest to the involvement of plumes. The re-assembly of dispersed continental fragments after the breakup of a supercontinent occurs through complex processes involving ‘introversion’, ‘extroversion’ or a combination of both, with the closure of the intervening ocean occurring through Pacific-type or Atlantic-type processes. The timescales of the assembly and dispersion of supercontinents have varied through the Earth history, and appear to be closely linked with the processes and duration of superplume genesis. The widely held view that the volume of continental crust has increased over time has been challenged in recent works and current models propose that plate tectonics creates and destroys Earth's continental crust with more crust being destroyed than created. The creation–destruction balance changes over a supercontinent cycle, with a higher crustal growth through magmatic influx during supercontinent break-up as compared to the tectonic erosion and sediment-trapped subduction in convergent margins associated with supercontinent assembly which erodes the continental crust. Ongoing subduction erosion also occurs at the leading edges of dispersing plates, which also contributes to crustal destruction, although this is only a temporary process. The previous numerical studies of mantle convection suggested that there is a significant feedback between mantle convection and continental drift. The process of assembly of supercontinents induces a temperature increase beneath the supercontinent due to the thermal insulating effec