EGU2020-19611
https://doi.org/10.5194/egusphere-egu2020-19611
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Vertically Driven Dynamics and Magmatism of Rapid Subduction Initiation in the Western Pacific

Ben Maunder1, Saskia Goes2, Julie Prytulak3, and Mark Reagan4
Ben Maunder et al.
  • 1Imperial College London, South Kensington, London, UK (b.maunder@imperial.ac.uk)
  • 2Imperial College London, South Kensington, London, UK (s.goes@imperial.ac.uk)
  • 3Durham University, Durham, UK (julie.prytulak@durham.ac.uk)
  • 4University of Iowa, Iowa City, USA (mark-reagan@uiowa.edu)

Plate tectonics requires the formation of plate boundaries. Particularly important is the enigmatic initiation of subduction: the sliding of one plate below the other, and the primary driver of plate tectonics. A continuous, in situ record of subduction initiation was recovered by the International Ocean Discovery Program Expedition 352, which drilled a segment of the fore-arc of the Izu-Bonin-Mariana subduction system, revealing a distinct magmatic progression with a rapid timescale (approximately 1 million years). Here, using numerical models, we demonstrate that these observations cannot be produced by previously proposed horizontal external forcing. Instead a geodynamic evolution that is dominated by internal, vertical forces produces both the temporal and spatial distribution of magmatic products, and progresses to self-sustained subduction. Such a primarily internally driven initiation event is necessarily whole-plate scale and the rock sequence generated (also found along the Tethyan margin) may be considered as a smoking gun for this type of event.

How to cite: Maunder, B., Goes, S., Prytulak, J., and Reagan, M.: Vertically Driven Dynamics and Magmatism of Rapid Subduction Initiation in the Western Pacific, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19611, https://doi.org/10.5194/egusphere-egu2020-19611, 2020

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