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Dynamics of subduction initiation with different evolutionary pathways

Leng, Wei and Gurnis, Michael (2011) Dynamics of subduction initiation with different evolutionary pathways. Geochemistry, Geophysics, Geosystems, 12 . Q12018. ISSN 1525-2027. doi:10.1029/2011GC003877.

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Changes of plate motion may have induced subduction initiation (SI), but the tectonic history of SI is different from one subduction zone to another. Izu-Bonin-Mariana (IBM) SI, accompanied by strong backarc spreading and voluminous eruption of Boninites, contrasts with the Aleutians which shows neither. Using finite element models, we explore visco-elasto-plastic parameters and driving boundary conditions for SI evolution. With an imposed velocity, we find three different evolutionary modes of SI: continuous without backarc spreading, continuous with backarc spreading and a segmented mode. With an increase in the coefficient of friction and a decrease in the rate of plastic weakening, the amount of convergence needed for SI increases from ∼20 to ∼220 km, while the mode changes from segmented to continuous with backarc spreading and eventually to continuous without backarc spreading. If the imposed velocity boundary condition is replaced with an imposed stress, the amount of convergence needed for SI is reduced and backarc spreading does not occur. These geodynamic models provide a basis for understanding the divergent geological pathways of SI. First, IBM evolution is consistent with subduction of an old strong plate with an imposed velocity which founders causing intense backarc spreading and Boninitic volcanism. Second, the New Hebrides SI is in the segmented mode due to its weak plate strength. Third, the Puysegur SI is in the continuous without backarc spreading mode with no associated volcanic activities. Fourth, the Aleutians SI has neither trench rollback nor backarc spreading because the slab is regulated by constant ridge-push forces.

Item Type:Article
Related URLs:
Gurnis, Michael0000-0003-1704-597X
Additional Information:© 2011 American Geophysical Union. Received 16 September 2011; accepted 11 November 2011; published 28 December 2011. This work was supported by the National Science Foundation (NSF EAR-0810303) and the Gordon and Betty Moore Foundation through the Caltech Tectonics Observatory. This is contribution 179 of the Caltech Tectonics Observatory. We thank Satoru Honda for a helpful review of the manuscript.
Group:Caltech Tectonics Observatory, Seismological Laboratory
Funding AgencyGrant Number
Gordon and Betty Moore FoundationUNSPECIFIED
Subject Keywords:backarc spreading; evolutionary pathways; subduction initiation
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Tectonics Observatory179
Classification Code:0545 Computational Geophysics: Modeling (1952, 4255, 4316); 3060 Marine Geology and Geophysics: Subduction zone processes (1031, 3613, 8170, 8413); 8034 Structural Geology: Rheology and friction of fault zones (8163)
Record Number:CaltechAUTHORS:20120203-145827743
Persistent URL:
Official Citation:Leng, W., and M. Gurnis (2011), Dynamics of subduction initiation with different evolutionary pathways, Geochem. Geophys. Geosyst., 12, Q12018, doi:10.1029/2011GC003877.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:29133
Deposited On:06 Feb 2012 15:37
Last Modified:09 Nov 2021 17:04

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