Supercontinent cycles, true polar wander, and very long-wavelength mantle convection
We show in this paper that mobile-lid mantle convection in a three-dimensional spherical shell with observationally constrained mantle viscosity structure, and realistic convective vigor and internal heating rate is characterized by either a spherical harmonic degree-1 planform with a major upwellin...
| Main Authors: | , , , |
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| Format: | Journal Article |
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Elsevier Science BV
2007
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| Online Access: | http://hdl.handle.net/20.500.11937/7131 |
| _version_ | 1848745277984342016 |
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| author | Zhong, S. Zhang, N. Li, Zheng-Xiang Roberts, J. |
| author_facet | Zhong, S. Zhang, N. Li, Zheng-Xiang Roberts, J. |
| author_sort | Zhong, S. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We show in this paper that mobile-lid mantle convection in a three-dimensional spherical shell with observationally constrained mantle viscosity structure, and realistic convective vigor and internal heating rate is characterized by either a spherical harmonic degree-1 planform with a major upwelling in one hemisphere and a major downwelling in the other hemisphere when continents are absent, or a degree-2 planform with two antipodal major upwellings when a supercontinent is present. We propose that due to modulation of continents, these two modes of mantle convection alternate within the Earth's mantle, causing the cyclic processes of assembly and breakup of supercontinents including Rodinia and Pangea in the last 1 Ga. Our model suggests that the largely degree-2 structure for the present-day mantle with the Africa and Pacific antipodal superplumes, is a natural consequence of this dynamic process of very long-wavelength mantle convection interacting with supercontinent Pangea. Our model explains the basic features of true polar wander (TPW) events for Rodinia and Pangea including their equatorial locations and large variability of TPW inferred from paleomagnetic studies. Our model also suggests that TPW is expected to be more variable and large during supercontinent assembly, but small after a supercontinent acquires its equatorial location and during its subsequent dispersal. |
| first_indexed | 2025-11-14T06:14:49Z |
| format | Journal Article |
| id | curtin-20.500.11937-7131 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T06:14:49Z |
| publishDate | 2007 |
| publisher | Elsevier Science BV |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-71312017-09-13T16:02:57Z Supercontinent cycles, true polar wander, and very long-wavelength mantle convection Zhong, S. Zhang, N. Li, Zheng-Xiang Roberts, J. supercontinents superplumes true polar wander mantle convection We show in this paper that mobile-lid mantle convection in a three-dimensional spherical shell with observationally constrained mantle viscosity structure, and realistic convective vigor and internal heating rate is characterized by either a spherical harmonic degree-1 planform with a major upwelling in one hemisphere and a major downwelling in the other hemisphere when continents are absent, or a degree-2 planform with two antipodal major upwellings when a supercontinent is present. We propose that due to modulation of continents, these two modes of mantle convection alternate within the Earth's mantle, causing the cyclic processes of assembly and breakup of supercontinents including Rodinia and Pangea in the last 1 Ga. Our model suggests that the largely degree-2 structure for the present-day mantle with the Africa and Pacific antipodal superplumes, is a natural consequence of this dynamic process of very long-wavelength mantle convection interacting with supercontinent Pangea. Our model explains the basic features of true polar wander (TPW) events for Rodinia and Pangea including their equatorial locations and large variability of TPW inferred from paleomagnetic studies. Our model also suggests that TPW is expected to be more variable and large during supercontinent assembly, but small after a supercontinent acquires its equatorial location and during its subsequent dispersal. 2007 Journal Article http://hdl.handle.net/20.500.11937/7131 10.1016/j.epsl.2007.07.049 Elsevier Science BV restricted |
| spellingShingle | supercontinents superplumes true polar wander mantle convection Zhong, S. Zhang, N. Li, Zheng-Xiang Roberts, J. Supercontinent cycles, true polar wander, and very long-wavelength mantle convection |
| title | Supercontinent cycles, true polar wander, and very long-wavelength mantle convection |
| title_full | Supercontinent cycles, true polar wander, and very long-wavelength mantle convection |
| title_fullStr | Supercontinent cycles, true polar wander, and very long-wavelength mantle convection |
| title_full_unstemmed | Supercontinent cycles, true polar wander, and very long-wavelength mantle convection |
| title_short | Supercontinent cycles, true polar wander, and very long-wavelength mantle convection |
| title_sort | supercontinent cycles, true polar wander, and very long-wavelength mantle convection |
| topic | supercontinents superplumes true polar wander mantle convection |
| url | http://hdl.handle.net/20.500.11937/7131 |