Fat Plumes May Reflect the Complex Rheology of the Lower Mantle
Abstract Recent tomographic imaging of the mantle below major hot spots shows slow seismic velocities extending down to the core‐mantle boundary, confirming the existence of mantle plumes. However, these plumes are much thicker than previously thought. Using new laboratory experiments and scaling la...
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| Format: | Article |
| Language: | English |
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Wiley
2018-02-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1002/2017GL076575 |
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| _version_ | 1849728014425784320 |
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| author | A. Davaille Ph. Carrez P. Cordier |
| author_facet | A. Davaille Ph. Carrez P. Cordier |
| author_sort | A. Davaille |
| collection | DOAJ |
| description | Abstract Recent tomographic imaging of the mantle below major hot spots shows slow seismic velocities extending down to the core‐mantle boundary, confirming the existence of mantle plumes. However, these plumes are much thicker than previously thought. Using new laboratory experiments and scaling laws, we show that thermal plumes developing in a visco‐plastic fluid present much larger diameters than plumes developing in a Newtonian fluid. Such a rheology requiring a yield stress is consistent with a lower mantle predominantly deforming by pure dislocation climb. Yield stress values between 1 and 10 MPa, implying dislocation densities between 108 and 1010 m−2, would be sufficient to reproduce the plumes morphology observed in tomographic images. |
| format | Article |
| id | doaj-art-e81c2e0d44e54263a2bfff2f455293b0 |
| institution | DOAJ |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2018-02-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-e81c2e0d44e54263a2bfff2f455293b02025-08-20T03:09:42ZengWileyGeophysical Research Letters0094-82761944-80072018-02-014531349135410.1002/2017GL076575Fat Plumes May Reflect the Complex Rheology of the Lower MantleA. Davaille0Ph. Carrez1P. Cordier2Laboratoire FAST CNRS/University of Paris‐Sud/University of Paris‐Saclay Orsay FranceUniversity of Lille, INRA, ENSCL, UMR 8207‐UMET‐Unite Materiaux et Transformations Lille FranceUniversity of Lille, INRA, ENSCL, UMR 8207‐UMET‐Unite Materiaux et Transformations Lille FranceAbstract Recent tomographic imaging of the mantle below major hot spots shows slow seismic velocities extending down to the core‐mantle boundary, confirming the existence of mantle plumes. However, these plumes are much thicker than previously thought. Using new laboratory experiments and scaling laws, we show that thermal plumes developing in a visco‐plastic fluid present much larger diameters than plumes developing in a Newtonian fluid. Such a rheology requiring a yield stress is consistent with a lower mantle predominantly deforming by pure dislocation climb. Yield stress values between 1 and 10 MPa, implying dislocation densities between 108 and 1010 m−2, would be sufficient to reproduce the plumes morphology observed in tomographic images.https://doi.org/10.1002/2017GL076575Mantle plumesnon‐Newtonian rheologydislocation climblower mantle convectiontomography imageslaboratory experiments |
| spellingShingle | A. Davaille Ph. Carrez P. Cordier Fat Plumes May Reflect the Complex Rheology of the Lower Mantle Geophysical Research Letters Mantle plumes non‐Newtonian rheology dislocation climb lower mantle convection tomography images laboratory experiments |
| title | Fat Plumes May Reflect the Complex Rheology of the Lower Mantle |
| title_full | Fat Plumes May Reflect the Complex Rheology of the Lower Mantle |
| title_fullStr | Fat Plumes May Reflect the Complex Rheology of the Lower Mantle |
| title_full_unstemmed | Fat Plumes May Reflect the Complex Rheology of the Lower Mantle |
| title_short | Fat Plumes May Reflect the Complex Rheology of the Lower Mantle |
| title_sort | fat plumes may reflect the complex rheology of the lower mantle |
| topic | Mantle plumes non‐Newtonian rheology dislocation climb lower mantle convection tomography images laboratory experiments |
| url | https://doi.org/10.1002/2017GL076575 |
| work_keys_str_mv | AT adavaille fatplumesmayreflectthecomplexrheologyofthelowermantle AT phcarrez fatplumesmayreflectthecomplexrheologyofthelowermantle AT pcordier fatplumesmayreflectthecomplexrheologyofthelowermantle |