Deflection of mantle flow beneath subducting slabs and the origin of subslab anisotropy
Global compilations of subslab shear wave splitting parameters show a mix of trench‐parallel and trench‐perpendicular fast directions that often directly contradict predictions from two‐dimensional models of slab‐entrained flow. Here we show that subslab anisotropy is consistent with three‐dimension...
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Published in | Geophysical research letters Vol. 41; no. 19; pp. 6734 - 6742 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Washington
Blackwell Publishing Ltd
16.10.2014
John Wiley & Sons, Inc |
Subjects | |
Online Access | Get full text |
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Summary: | Global compilations of subslab shear wave splitting parameters show a mix of trench‐parallel and trench‐perpendicular fast directions that often directly contradict predictions from two‐dimensional models of slab‐entrained flow. Here we show that subslab anisotropy is consistent with three‐dimensional geodynamic models that feature the interaction between subducting slabs and regional mantle flow. Each model represents a specific region for which high‐quality source‐side shear wave splitting data are available. We compare the distribution of finite strain in the models with shear wave splitting observations, showing that both trench‐parallel and trench‐perpendicular fast directions can be explained by deflection of regional mantle flow around or beneath subducted slabs. Subslab maximum elongation directions calculated from our models depend on a combination of geometry factors (such as slab dip angle and maximum depth), mechanical parameters (such as decoupling between the slab and the subjacent mantle), and the orientation and magnitude of the regional mantle flow.
Key Points
Regionally specific models of flow beneath subducting slabs are presentedSubslab dynamics controlled by deflection of mantle flow in vicinity of slabPredicted finite strain directions generally agree with anisotropy observations |
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Bibliography: | NSF - No. EAR-0911286 (M.D.L.); No. EAR-0911151; No. OCE-1060878 ArticleID:GRL52146 NSF Graduate Research Fellowship - No. DGE-1122492 ReadmeTable S1Text S1Movie S1Movie S2Movie S3Movie S4Figure S1Figure S2Figure S3Figure S4Figure S5Figure S6Figure S7Figure S8Figure S9 istex:D0A7632FD7A457694824FE94C5BD8C4ADCA8C0AE ark:/67375/WNG-V6F4W5XJ-8 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0094-8276 1944-8007 |
DOI: | 10.1002/2014GL060914 |