Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

Timescales of successful and failed subduction: insights from numerical modelling

Knight, B. S., Davies, J. H. and Capitanio, F. A. 2021. Timescales of successful and failed subduction: insights from numerical modelling. Geophysical Journal International 225 (1) , pp. 261-276. 10.1093/gji/ggaa410

[img] PDF - Accepted Post-Print Version
Download (11MB)

Abstract

The relatively short duration of the early stages of subduction results in a poor geological record, limiting our understanding of this critical stage. Here, we utilize a 2D numerical model of incipient subduction, that is the stage after a plate margin has formed with a slab tip that extends to a shallow depth and address the conditions under which subduction continues or fails. We assess energy budgets during the evolution from incipient subduction to either a failed or successful state, showing how the growth of potential energy, and slab pull, is resisted by the viscous dissipation within the lithosphere and the mantle. The role of rheology is also investigated, as deformation mechanisms operating in the crust and mantle facilitate subduction. In all models, the onset of subduction is characterized by high lithospheric viscous dissipation and low convergence velocities, whilst successful subduction sees the mantle become the main area of viscous dissipation. In contrast, failed subduction is defined by the lithospheric viscous dissipation exceeding the lithospheric potential energy release rate and velocities tend towards zero. We show that development of a subduction zone depends on the convergence rate, required to overcome thermal diffusion and to localise deformation along the margin. The results propose a minimum convergence rate of ∼ 0.5 cm yr−1 is required to reach a successful state, with 100 km of convergence over 20 Myr, emphasizing the critical role of the incipient stage.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Earth and Ocean Sciences
Publisher: Oxford University Press
ISSN: 0956-540X
Date of First Compliant Deposit: 10 September 2020
Date of Acceptance: 25 August 2020
Last Modified: 07 Oct 2021 09:52
URI: http://orca.cardiff.ac.uk/id/eprint/134776

Actions (repository staff only)

Edit Item Edit Item