Dynamics of subduction initiation with different evolutionary pathways
- Creators
- Leng, Wei
- Gurnis, Michael
Abstract
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.
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.Attached Files
Published - Leng2011p17024Geochem_Geophy_Geosy.pdf
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Additional details
- Eprint ID
- 29133
- Resolver ID
- CaltechAUTHORS:20120203-145827743
- EAR-0810303
- NSF
- Gordon and Betty Moore Foundation
- Created
-
2012-02-06Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field
- Caltech groups
- Caltech Tectonics Observatory, Seismological Laboratory
- Other Numbering System Name
- Caltech Tectonics Observatory
- Other Numbering System Identifier
- 179