Bathymetry of Valdivia Bank, Walvis Ridge, South Atlantic Ocean: Implications for Structure and Geologic History of a Hot Spot Plateau
Abstract Valdivia Bank is an oceanic plateau in the South Atlantic formed by hot spot magmatism at the Mid‐Atlantic Ridge during the Late Cretaceous. It is part of the Walvis Ridge, an aseismic ridge and seamount chain widely considered to be formed by age‐progressive volcanism from the Tristan‐Goug...
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| Format: | Article |
| Language: | English |
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Wiley
2022-11-01
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| Series: | Geochemistry, Geophysics, Geosystems |
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| Online Access: | https://doi.org/10.1029/2022GC010624 |
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| author | E. Contreras P. Jiménez García W. W. Sager S. Thoram K. Hoernle R. Sarralde H. Zhou |
| author_facet | E. Contreras P. Jiménez García W. W. Sager S. Thoram K. Hoernle R. Sarralde H. Zhou |
| author_sort | E. Contreras |
| collection | DOAJ |
| description | Abstract Valdivia Bank is an oceanic plateau in the South Atlantic formed by hot spot magmatism at the Mid‐Atlantic Ridge during the Late Cretaceous. It is part of the Walvis Ridge, an aseismic ridge and seamount chain widely considered to be formed by age‐progressive volcanism from the Tristan‐Gough plume. To better understand the formation and history of this edifice, we developed a bathymetric map of Valdivia Bank by merging available multibeam echosounder data sets with a bathymetry grid based mainly on satellite altimetry (SRTM15+). The bathymetric map reveals previously unresolved features including extensive rift grabens, volcanic mounds and knolls, and large‐scale sediment transport systems. After Valdivia Bank was emplaced and probably eroded at sea level, it underwent a period of rifting, followed by a secondary magmatic pulse that caused regional uplift to sea‐level, followed by subsidence to current depths. Shallow banks at depths of ∼1,000 m are the result of a thick sediment pile atop uplifted volcanic crust. Several shallower mounds (∼1,000–520 m) and a guyot (∼220 m) likely resulted from coral reef growth atop one or more volcanic pedestals formed during the younger Cenozoic magmatic event. As sediments accumulated on the shallow platforms, sediment transport systems developed as gullies, channels and mass transport deposits carved valleys and troughs, shedding sediment into abyssal fans at the plateau base. The new bathymetric map demonstrates that oceanic plateaus are geologically active long after initial emplacement. |
| first_indexed | 2024-03-11T12:56:47Z |
| format | Article |
| id | doaj.art-b0a12e20b978439ebf1e30f3882e49c0 |
| institution | Directory Open Access Journal |
| issn | 1525-2027 |
| language | English |
| last_indexed | 2024-03-11T12:56:47Z |
| publishDate | 2022-11-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geochemistry, Geophysics, Geosystems |
| spelling | doaj.art-b0a12e20b978439ebf1e30f3882e49c02023-11-03T17:00:48ZengWileyGeochemistry, Geophysics, Geosystems1525-20272022-11-012311n/an/a10.1029/2022GC010624Bathymetry of Valdivia Bank, Walvis Ridge, South Atlantic Ocean: Implications for Structure and Geologic History of a Hot Spot PlateauE. Contreras0P. Jiménez García1W. W. Sager2S. Thoram3K. Hoernle4R. Sarralde5H. Zhou6Department of Earth and Atmospheric Sciences University of Houston Houston TX USATragsatec, Pasaje de Cala Figuera 6 Planta Baja Palma de Mallorca SpainDepartment of Earth and Atmospheric Sciences University of Houston Houston TX USADepartment of Earth and Atmospheric Sciences University of Houston Houston TX USAGEOMAR Helmholtz Centre for Ocean Research Kiel Kiel GermanyInstituto Español de Oceanografia IEO‐CSIC Subida a Radio Faro Vigo SpainDepartment of Earth and Atmospheric Sciences University of Houston Houston TX USAAbstract Valdivia Bank is an oceanic plateau in the South Atlantic formed by hot spot magmatism at the Mid‐Atlantic Ridge during the Late Cretaceous. It is part of the Walvis Ridge, an aseismic ridge and seamount chain widely considered to be formed by age‐progressive volcanism from the Tristan‐Gough plume. To better understand the formation and history of this edifice, we developed a bathymetric map of Valdivia Bank by merging available multibeam echosounder data sets with a bathymetry grid based mainly on satellite altimetry (SRTM15+). The bathymetric map reveals previously unresolved features including extensive rift grabens, volcanic mounds and knolls, and large‐scale sediment transport systems. After Valdivia Bank was emplaced and probably eroded at sea level, it underwent a period of rifting, followed by a secondary magmatic pulse that caused regional uplift to sea‐level, followed by subsidence to current depths. Shallow banks at depths of ∼1,000 m are the result of a thick sediment pile atop uplifted volcanic crust. Several shallower mounds (∼1,000–520 m) and a guyot (∼220 m) likely resulted from coral reef growth atop one or more volcanic pedestals formed during the younger Cenozoic magmatic event. As sediments accumulated on the shallow platforms, sediment transport systems developed as gullies, channels and mass transport deposits carved valleys and troughs, shedding sediment into abyssal fans at the plateau base. The new bathymetric map demonstrates that oceanic plateaus are geologically active long after initial emplacement.https://doi.org/10.1029/2022GC010624multibeam bathymetryWalvis Ridgeoceanic plateauhot spot volcanismseamountValdivia Bank |
| spellingShingle | E. Contreras P. Jiménez García W. W. Sager S. Thoram K. Hoernle R. Sarralde H. Zhou Bathymetry of Valdivia Bank, Walvis Ridge, South Atlantic Ocean: Implications for Structure and Geologic History of a Hot Spot Plateau Geochemistry, Geophysics, Geosystems multibeam bathymetry Walvis Ridge oceanic plateau hot spot volcanism seamount Valdivia Bank |
| title | Bathymetry of Valdivia Bank, Walvis Ridge, South Atlantic Ocean: Implications for Structure and Geologic History of a Hot Spot Plateau |
| title_full | Bathymetry of Valdivia Bank, Walvis Ridge, South Atlantic Ocean: Implications for Structure and Geologic History of a Hot Spot Plateau |
| title_fullStr | Bathymetry of Valdivia Bank, Walvis Ridge, South Atlantic Ocean: Implications for Structure and Geologic History of a Hot Spot Plateau |
| title_full_unstemmed | Bathymetry of Valdivia Bank, Walvis Ridge, South Atlantic Ocean: Implications for Structure and Geologic History of a Hot Spot Plateau |
| title_short | Bathymetry of Valdivia Bank, Walvis Ridge, South Atlantic Ocean: Implications for Structure and Geologic History of a Hot Spot Plateau |
| title_sort | bathymetry of valdivia bank walvis ridge south atlantic ocean implications for structure and geologic history of a hot spot plateau |
| topic | multibeam bathymetry Walvis Ridge oceanic plateau hot spot volcanism seamount Valdivia Bank |
| url | https://doi.org/10.1029/2022GC010624 |
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