Supercontinent Cycle and Thermochemical Structure in the Mantle: Inference from Two-Dimensional Numerical Simulations of Mantle Convection
In this study, we conduct numerical simulations of thermochemical mantle convection in a 2D spherical annulus with a highly viscous lid drifting along the top surface, in order to investigate the interrelation between the motion of the surface (super)continent and the behavior of chemical heterogene...
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| Format: | Article |
| Language: | English |
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MDPI AG
2017-12-01
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| Series: | Geosciences |
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| Online Access: | https://www.mdpi.com/2076-3263/7/4/126 |
| _version_ | 1818256814334017536 |
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| author | Masanori Kameyama Akari Harada |
| author_facet | Masanori Kameyama Akari Harada |
| author_sort | Masanori Kameyama |
| collection | DOAJ |
| description | In this study, we conduct numerical simulations of thermochemical mantle convection in a 2D spherical annulus with a highly viscous lid drifting along the top surface, in order to investigate the interrelation between the motion of the surface (super)continent and the behavior of chemical heterogeneities imposed in the lowermost mantle. Our calculations show that assembly and dispersal of supercontinents occur in a cyclic manner when a sufficient amount of chemically-distinct dense material resides in the base of the mantle against the convective mixing. The motion of surface continents is significantly driven by strong ascending plumes originating around the dense materials in the lowermost mantle. The hot dense materials horizontally move in response to the motion of continents at the top surface, which in turn horizontally move the ascending plumes leading to the breakup of newly-formed supercontinents. We also found that the motion of dense materials in the base of the mantle is driven toward the region beneath a newly-formed supercontinent largely by the horizontal flow induced by cold descending flows from the top surface occurring away from the (super)continent. Our findings imply that the dynamic behavior of cold descending plumes is the key to the understanding of the relationship between the supercontinent cycle on the Earth’s surface and the thermochemical structures in the lowermost mantle, through modulating not only the positions of chemically-dense materials, but also the occurrence of ascending plumes around them. |
| first_indexed | 2024-12-12T17:33:44Z |
| format | Article |
| id | doaj.art-2b097b2c54304bcd989082d75b39b0bd |
| institution | Directory Open Access Journal |
| issn | 2076-3263 |
| language | English |
| last_indexed | 2024-12-12T17:33:44Z |
| publishDate | 2017-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Geosciences |
| spelling | doaj.art-2b097b2c54304bcd989082d75b39b0bd2022-12-22T00:17:16ZengMDPI AGGeosciences2076-32632017-12-017412610.3390/geosciences7040126geosciences7040126Supercontinent Cycle and Thermochemical Structure in the Mantle: Inference from Two-Dimensional Numerical Simulations of Mantle ConvectionMasanori Kameyama0Akari Harada1Geodynamics Research Center, Ehime University, 2–5 Bunkyo-cho, Matsuyama 790-8577, Ehime, JapanGeodynamics Research Center, Ehime University, 2–5 Bunkyo-cho, Matsuyama 790-8577, Ehime, JapanIn this study, we conduct numerical simulations of thermochemical mantle convection in a 2D spherical annulus with a highly viscous lid drifting along the top surface, in order to investigate the interrelation between the motion of the surface (super)continent and the behavior of chemical heterogeneities imposed in the lowermost mantle. Our calculations show that assembly and dispersal of supercontinents occur in a cyclic manner when a sufficient amount of chemically-distinct dense material resides in the base of the mantle against the convective mixing. The motion of surface continents is significantly driven by strong ascending plumes originating around the dense materials in the lowermost mantle. The hot dense materials horizontally move in response to the motion of continents at the top surface, which in turn horizontally move the ascending plumes leading to the breakup of newly-formed supercontinents. We also found that the motion of dense materials in the base of the mantle is driven toward the region beneath a newly-formed supercontinent largely by the horizontal flow induced by cold descending flows from the top surface occurring away from the (super)continent. Our findings imply that the dynamic behavior of cold descending plumes is the key to the understanding of the relationship between the supercontinent cycle on the Earth’s surface and the thermochemical structures in the lowermost mantle, through modulating not only the positions of chemically-dense materials, but also the occurrence of ascending plumes around them.https://www.mdpi.com/2076-3263/7/4/126mantle convectionsupercontinent cycleschemical heterogeneity in the lowermost mantle |
| spellingShingle | Masanori Kameyama Akari Harada Supercontinent Cycle and Thermochemical Structure in the Mantle: Inference from Two-Dimensional Numerical Simulations of Mantle Convection Geosciences mantle convection supercontinent cycles chemical heterogeneity in the lowermost mantle |
| title | Supercontinent Cycle and Thermochemical Structure in the Mantle: Inference from Two-Dimensional Numerical Simulations of Mantle Convection |
| title_full | Supercontinent Cycle and Thermochemical Structure in the Mantle: Inference from Two-Dimensional Numerical Simulations of Mantle Convection |
| title_fullStr | Supercontinent Cycle and Thermochemical Structure in the Mantle: Inference from Two-Dimensional Numerical Simulations of Mantle Convection |
| title_full_unstemmed | Supercontinent Cycle and Thermochemical Structure in the Mantle: Inference from Two-Dimensional Numerical Simulations of Mantle Convection |
| title_short | Supercontinent Cycle and Thermochemical Structure in the Mantle: Inference from Two-Dimensional Numerical Simulations of Mantle Convection |
| title_sort | supercontinent cycle and thermochemical structure in the mantle inference from two dimensional numerical simulations of mantle convection |
| topic | mantle convection supercontinent cycles chemical heterogeneity in the lowermost mantle |
| url | https://www.mdpi.com/2076-3263/7/4/126 |
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