Wong, K orcid.org/0000-0002-5173-0498, Ferguson, D orcid.org/0000-0003-0612-6512, Matthews, S et al. (4 more authors) (2022) Exploring rift geodynamics in Ethiopia through olivine-spinel Al-exchange thermometry and rare-earth element distributions. Earth and Planetary Science Letters, 597. 117820. ISSN 0012-821X
Abstract
Understanding the process of continental break-up requires knowledge of the geodynamics of mature rift systems close to the point of plate rupture. In Ethiopia, late-stage continental rifting occurs in a magma-rich setting where extensional processes correlate closely with magmatic and volcanic activity. Unravelling the role that mantle and lithospheric dynamics play in sustaining rifting in Ethiopia is key to improving models of late-stage continental rift evolution. In this study we provide petrological constraints on the physical characteristics of magma production using volcanic samples from the northern Main Ethiopian Rift (MER) and central Afar. Olivine crystallisation temperatures provide information about the thermal state of mantle-derived magmas generated by the mantle during upwelling and melting. These temperatures, determined by Al-exchange thermometry, are used in conjunction with other geochemical and geophysical constraints in inversion models of melting a multi-lithology mantle to find the best- fitting geodynamic parameters that can reproduce observed magma compositions and melt volumes. Our model results suggest that the potential temperature of the Ethiopian mantle is hotter than ambient mantle by ≥ 150◦C, and is elevated to a similar degree across the MER and Afar. We predict significant variations in lithospheric thickness between the MER (90 km) and Afar (50-70 km), with Afar also likely to have a higher portion of fusible mantle domains. This thinner lithosphere and/or more productive mantle is required to generate the larger volumes of magma inferred to have been intruded into the Afar crust. The geodynamic differences between these two settings can be attributed to the more-evolved state of the Afar rift and its proximity to the centre of the Afar plume.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2022 The Author(s). This is an open access article published under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited. |
Keywords: | continental rifting, melt generation, melt chemistry, East African Rift, melt thermometry |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst of Geophysics and Tectonics (IGT) (Leeds) |
Funding Information: | Funder Grant number NERC DTP NE/L002574/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 15 Sep 2022 15:07 |
Last Modified: | 25 Jun 2023 23:06 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.epsl.2022.117820 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:190991 |