The root to the Galápagos mantle plume on the core-mantle boundary
Ultra-low velocity zones (ULVZs) are thin anomalous patches on the boundary between the Earth's core and mantle, revealed by their effects on the seismic waves that propagate through them. Here we map a broad ULVZ near the Galápagos hotspot using shear-diffracted waves. Forward modelling assu...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
McGill University
2022-10-01
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| Series: | Seismica |
| Subjects: | |
| Online Access: | https://seismica.library.mcgill.ca/article/view/197 |
| _version_ | 1827759293904977920 |
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| author | Sanne Cottaar Carl Martin Zhi Li Rita Parai |
| author_facet | Sanne Cottaar Carl Martin Zhi Li Rita Parai |
| author_sort | Sanne Cottaar |
| collection | DOAJ |
| description |
Ultra-low velocity zones (ULVZs) are thin anomalous patches on the boundary between the Earth's core and mantle, revealed by their effects on the seismic waves that propagate through them. Here we map a broad ULVZ near the Galápagos hotspot using shear-diffracted waves. Forward modelling assuming a cylindrical shape shows the patch is ~600 km wide, ~20 km high, and its shear velocities are ~25% reduced. The ULVZ is comparable to other broad ULVZs mapped on the core-mantle boundary near Hawaii, Iceland, and Samoa. Strikingly, all four hotspots where the mantle plume appears rooted by these ‘mega-ULVZs’, show similar anomalous isotopic signatures in He, Ne, and W in their ocean island basalts. This correlation suggests mega-ULVZs might be primordial or caused by interaction with the core, and some material from ULVZs is entrained within the plume. For the Galápagos, the connection implies the plume is offset to the west towards the base of the mantle.
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| first_indexed | 2024-03-11T09:19:05Z |
| format | Article |
| id | doaj.art-92be183ab1fa45b693e2fdd7bafaf671 |
| institution | Directory Open Access Journal |
| issn | 2816-9387 |
| language | English |
| last_indexed | 2024-03-11T09:19:05Z |
| publishDate | 2022-10-01 |
| publisher | McGill University |
| record_format | Article |
| series | Seismica |
| spelling | doaj.art-92be183ab1fa45b693e2fdd7bafaf6712023-11-16T18:29:27ZengMcGill UniversitySeismica2816-93872022-10-011110.26443/seismica.v1i1.197The root to the Galápagos mantle plume on the core-mantle boundary Sanne Cottaar0Carl Martin1Zhi Li2Rita Parai3University of CambridgeUniversity of CambridgeUniversity of CambridgeWashington University in St Louis Ultra-low velocity zones (ULVZs) are thin anomalous patches on the boundary between the Earth's core and mantle, revealed by their effects on the seismic waves that propagate through them. Here we map a broad ULVZ near the Galápagos hotspot using shear-diffracted waves. Forward modelling assuming a cylindrical shape shows the patch is ~600 km wide, ~20 km high, and its shear velocities are ~25% reduced. The ULVZ is comparable to other broad ULVZs mapped on the core-mantle boundary near Hawaii, Iceland, and Samoa. Strikingly, all four hotspots where the mantle plume appears rooted by these ‘mega-ULVZs’, show similar anomalous isotopic signatures in He, Ne, and W in their ocean island basalts. This correlation suggests mega-ULVZs might be primordial or caused by interaction with the core, and some material from ULVZs is entrained within the plume. For the Galápagos, the connection implies the plume is offset to the west towards the base of the mantle. https://seismica.library.mcgill.ca/article/view/197SeismologyDeep EarthULVZGalapagos |
| spellingShingle | Sanne Cottaar Carl Martin Zhi Li Rita Parai The root to the Galápagos mantle plume on the core-mantle boundary Seismica Seismology Deep Earth ULVZ Galapagos |
| title | The root to the Galápagos mantle plume on the core-mantle boundary |
| title_full | The root to the Galápagos mantle plume on the core-mantle boundary |
| title_fullStr | The root to the Galápagos mantle plume on the core-mantle boundary |
| title_full_unstemmed | The root to the Galápagos mantle plume on the core-mantle boundary |
| title_short | The root to the Galápagos mantle plume on the core-mantle boundary |
| title_sort | root to the galapagos mantle plume on the core mantle boundary |
| topic | Seismology Deep Earth ULVZ Galapagos |
| url | https://seismica.library.mcgill.ca/article/view/197 |
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