40Ar/39Ar dating reveals over 30 million years of plume-ridge interaction formed the Rio Grande Rise
Abstract The Rio Grande Rise (RGR) oceanic plateau exhibits distinctly broad morphology compared to the linear, age-progressive Walvis Ridge (WR), despite both originating from the Tristan-Gough (T-G) plume. New 40Ar/39Ar ages (84–41 Ma) from RGR demonstrate prolonged coeval formation with WR at the...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2025-07-01
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| Series: | Communications Earth & Environment |
| Online Access: | https://doi.org/10.1038/s43247-025-02572-y |
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| Summary: | Abstract The Rio Grande Rise (RGR) oceanic plateau exhibits distinctly broad morphology compared to the linear, age-progressive Walvis Ridge (WR), despite both originating from the Tristan-Gough (T-G) plume. New 40Ar/39Ar ages (84–41 Ma) from RGR demonstrate prolonged coeval formation with WR at the Mid-Atlantic Ridge (MAR) during a ridge-centered plume configuration. These plume-ridge interactions coincided with a temporary microplate eventually incorporated into the South American Plate, explaining RGR’s broader spatial distribution. Backtracking reveals that absolute plate motion and southward plume drift shut off excess magma supply when the T-G plume moved south of large lateral MAR offsets, ending volcanism on the South American plate around 52 Ma—later than previously estimated. Although RGR’s erupted volume matches large igneous provinces, magmatic production rates were moderate, resembling modern-day Iceland rather than high-flux terrestrial large igneous provinces. This supports a ridge-centered plume origin over a high-flux magma pulse, demonstrating how plume-ridge configuration and microplate tectonics controlled the evolutionary divergence of these related South Atlantic volcanic features. |
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| ISSN: | 2662-4435 |