The Morphology of the Tasmantid Seamounts: Interactions Between Tectonic Inheritance and Magmatic Evolution
Abstract Basement structure is known to exert strong magmatic and morphological control on continental volcanoes, but relatively little is known about the structural control of submarine volcanoes. Here we investigate the morphology of the Tasmantid Seamounts, a >2,400 km long chain of age‐progre...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2018-10-01
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| Series: | Geochemistry, Geophysics, Geosystems |
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| Online Access: | https://doi.org/10.1029/2018GC007821 |
| _version_ | 1797685941338374144 |
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| author | F. D. Richards L. M. Kalnins A. B. Watts B. E. Cohen R. J. Beaman |
| author_facet | F. D. Richards L. M. Kalnins A. B. Watts B. E. Cohen R. J. Beaman |
| author_sort | F. D. Richards |
| collection | DOAJ |
| description | Abstract Basement structure is known to exert strong magmatic and morphological control on continental volcanoes, but relatively little is known about the structural control of submarine volcanoes. Here we investigate the morphology of the Tasmantid Seamounts, a >2,400 km long chain of age‐progressive intraplate volcanoes, ranging from 56 to 7 Ma. The seamounts are emplaced over the extinct Tasman Sea spreading center, which was active between 84 and 52 Ma. While thick sediment (∼1 km) obscures much of the basement, detailed morphological and geophysical analyses of the seamounts reveal a strong correlation between tectonic setting, seamount orientation, and volcanic structure, despite the ≥20 Ma interval between spreading cessation and seamount emplacement. Seamounts emplaced on fracture zones or spreading segment‐transform fault inside corners are typically large and elongate. Where original morphology is preserved, they often appear rugged and predominantly fissure‐fed. By contrast, comparatively smooth, conical seamounts with isolated dike‐fed flank cones are often found midsegment and at outside corners. Volcanic fabrics also align closely with the expected principal stress directions for strong mechanical coupling across transform faults. This behavior suggests the lithosphere is dissected by numerous deep faults, channeling magma along preexisting structural trends. Generally, low effective elastic thicknesses (<10 km) and lack of correlation with plate age at emplacement suggest that structural inheritance is also a major control on lithospheric strength near the extinct spreading center. Our study clearly demonstrates that, like in the continents, structural inheritance in oceanic lithosphere can exert significant control on the morphology of submarine volcanoes. |
| first_indexed | 2024-03-12T00:58:30Z |
| format | Article |
| id | doaj.art-cff1c11b0f6142f3aa44d65bc928e9d9 |
| institution | Directory Open Access Journal |
| issn | 1525-2027 |
| language | English |
| last_indexed | 2024-03-12T00:58:30Z |
| publishDate | 2018-10-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geochemistry, Geophysics, Geosystems |
| spelling | doaj.art-cff1c11b0f6142f3aa44d65bc928e9d92023-09-14T11:39:59ZengWileyGeochemistry, Geophysics, Geosystems1525-20272018-10-0119103870389110.1029/2018GC007821The Morphology of the Tasmantid Seamounts: Interactions Between Tectonic Inheritance and Magmatic EvolutionF. D. Richards0L. M. Kalnins1A. B. Watts2B. E. Cohen3R. J. Beaman4Department of Earth Sciences University of Oxford Oxford UKDepartment of Earth Sciences, Durham University Science Labs Durham UKDepartment of Earth Sciences University of Oxford Oxford UKScottish Universities Environmental Research Centre East Kilbride UKCollege of Science and Engineering James Cook University Cairns Queensland AustraliaAbstract Basement structure is known to exert strong magmatic and morphological control on continental volcanoes, but relatively little is known about the structural control of submarine volcanoes. Here we investigate the morphology of the Tasmantid Seamounts, a >2,400 km long chain of age‐progressive intraplate volcanoes, ranging from 56 to 7 Ma. The seamounts are emplaced over the extinct Tasman Sea spreading center, which was active between 84 and 52 Ma. While thick sediment (∼1 km) obscures much of the basement, detailed morphological and geophysical analyses of the seamounts reveal a strong correlation between tectonic setting, seamount orientation, and volcanic structure, despite the ≥20 Ma interval between spreading cessation and seamount emplacement. Seamounts emplaced on fracture zones or spreading segment‐transform fault inside corners are typically large and elongate. Where original morphology is preserved, they often appear rugged and predominantly fissure‐fed. By contrast, comparatively smooth, conical seamounts with isolated dike‐fed flank cones are often found midsegment and at outside corners. Volcanic fabrics also align closely with the expected principal stress directions for strong mechanical coupling across transform faults. This behavior suggests the lithosphere is dissected by numerous deep faults, channeling magma along preexisting structural trends. Generally, low effective elastic thicknesses (<10 km) and lack of correlation with plate age at emplacement suggest that structural inheritance is also a major control on lithospheric strength near the extinct spreading center. Our study clearly demonstrates that, like in the continents, structural inheritance in oceanic lithosphere can exert significant control on the morphology of submarine volcanoes.https://doi.org/10.1029/2018GC007821intraplate volcanismtectono‐magmatic interactiongravity anomalies and Earth structureseamount morphologyflexure and rheology of oceanic lithosphereeast Australian volcanism |
| spellingShingle | F. D. Richards L. M. Kalnins A. B. Watts B. E. Cohen R. J. Beaman The Morphology of the Tasmantid Seamounts: Interactions Between Tectonic Inheritance and Magmatic Evolution Geochemistry, Geophysics, Geosystems intraplate volcanism tectono‐magmatic interaction gravity anomalies and Earth structure seamount morphology flexure and rheology of oceanic lithosphere east Australian volcanism |
| title | The Morphology of the Tasmantid Seamounts: Interactions Between Tectonic Inheritance and Magmatic Evolution |
| title_full | The Morphology of the Tasmantid Seamounts: Interactions Between Tectonic Inheritance and Magmatic Evolution |
| title_fullStr | The Morphology of the Tasmantid Seamounts: Interactions Between Tectonic Inheritance and Magmatic Evolution |
| title_full_unstemmed | The Morphology of the Tasmantid Seamounts: Interactions Between Tectonic Inheritance and Magmatic Evolution |
| title_short | The Morphology of the Tasmantid Seamounts: Interactions Between Tectonic Inheritance and Magmatic Evolution |
| title_sort | morphology of the tasmantid seamounts interactions between tectonic inheritance and magmatic evolution |
| topic | intraplate volcanism tectono‐magmatic interaction gravity anomalies and Earth structure seamount morphology flexure and rheology of oceanic lithosphere east Australian volcanism |
| url | https://doi.org/10.1029/2018GC007821 |
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