Spatially variable CO2 degassing in the Main Ethiopian Rift: Implications for magma storage, volatile transport, and rift-related emissions
Deep carbon emissions from historically inactive volcanoes, hydrothermal, and tectonic structures are among the greatest unknowns in the long-term (∼Myr) carbon cycle. Recent estimates of diffuse CO2flux from the Eastern Rift of the East African Rift System (EARS) suggest this could equal emissions...
| Main Authors: | , , , , |
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| Format: | Journal article |
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Wiley
2017
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| _version_ | 1797104380125642752 |
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| author | Hunt, JA Zafu, A Mather, TA Pyle, DM Barry, PH |
| author_facet | Hunt, JA Zafu, A Mather, TA Pyle, DM Barry, PH |
| author_sort | Hunt, JA |
| collection | OXFORD |
| description | Deep carbon emissions from historically inactive volcanoes, hydrothermal, and tectonic structures are among the greatest unknowns in the long-term (∼Myr) carbon cycle. Recent estimates of diffuse CO2flux from the Eastern Rift of the East African Rift System (EARS) suggest this could equal emissions from the entire mid-ocean ridge system. We report new CO2surveys from the Main Ethiopian Rift (MER, northernmost EARS), and reassess the rift-related CO2flux. Since degassing in the MER is concentrated in discrete areas of volcanic and off-edifice activity, characterization of such areas is important for extrapolation to a rift-scale budget. Locations of hot springs and fumaroles along the rift show numerous geothermal areas away from volcanic edifices. With these new data, we estimate total CO2emissions from the central and northern MER as 0.52–4.36 Mt yr−1. Our extrapolated flux from the Eastern Rift is 3.9–32.7 Mt yr−1CO2, overlapping with lower end of the range presented in recent estimates. By scaling, we suggest that 6–18 Mt yr−1CO2flux can be accounted for by magmatic extension, which implies an important role for volatile-enriched lithosphere, crustal assimilation, and/or additional magmatic intrusion to account for the upper range of flux estimates. Our results also have implications for the nature of volcanism in the MER. Many geothermal areas are found >10 km from the nearest volcanic center, suggesting ongoing hazards associated with regional volcanism. |
| first_indexed | 2024-03-07T06:33:01Z |
| format | Journal article |
| id | oxford-uuid:f6ad28bd-6b3b-4338-847c-8f7ea8aa00bf |
| institution | University of Oxford |
| last_indexed | 2024-03-07T06:33:01Z |
| publishDate | 2017 |
| publisher | Wiley |
| record_format | dspace |
| spelling | oxford-uuid:f6ad28bd-6b3b-4338-847c-8f7ea8aa00bf2022-03-27T12:36:44ZSpatially variable CO2 degassing in the Main Ethiopian Rift: Implications for magma storage, volatile transport, and rift-related emissionsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:f6ad28bd-6b3b-4338-847c-8f7ea8aa00bfSymplectic Elements at OxfordWiley2017Hunt, JAZafu, AMather, TAPyle, DMBarry, PHDeep carbon emissions from historically inactive volcanoes, hydrothermal, and tectonic structures are among the greatest unknowns in the long-term (∼Myr) carbon cycle. Recent estimates of diffuse CO2flux from the Eastern Rift of the East African Rift System (EARS) suggest this could equal emissions from the entire mid-ocean ridge system. We report new CO2surveys from the Main Ethiopian Rift (MER, northernmost EARS), and reassess the rift-related CO2flux. Since degassing in the MER is concentrated in discrete areas of volcanic and off-edifice activity, characterization of such areas is important for extrapolation to a rift-scale budget. Locations of hot springs and fumaroles along the rift show numerous geothermal areas away from volcanic edifices. With these new data, we estimate total CO2emissions from the central and northern MER as 0.52–4.36 Mt yr−1. Our extrapolated flux from the Eastern Rift is 3.9–32.7 Mt yr−1CO2, overlapping with lower end of the range presented in recent estimates. By scaling, we suggest that 6–18 Mt yr−1CO2flux can be accounted for by magmatic extension, which implies an important role for volatile-enriched lithosphere, crustal assimilation, and/or additional magmatic intrusion to account for the upper range of flux estimates. Our results also have implications for the nature of volcanism in the MER. Many geothermal areas are found >10 km from the nearest volcanic center, suggesting ongoing hazards associated with regional volcanism. |
| spellingShingle | Hunt, JA Zafu, A Mather, TA Pyle, DM Barry, PH Spatially variable CO2 degassing in the Main Ethiopian Rift: Implications for magma storage, volatile transport, and rift-related emissions |
| title | Spatially variable CO2 degassing in the Main Ethiopian Rift: Implications for magma storage, volatile transport, and rift-related emissions |
| title_full | Spatially variable CO2 degassing in the Main Ethiopian Rift: Implications for magma storage, volatile transport, and rift-related emissions |
| title_fullStr | Spatially variable CO2 degassing in the Main Ethiopian Rift: Implications for magma storage, volatile transport, and rift-related emissions |
| title_full_unstemmed | Spatially variable CO2 degassing in the Main Ethiopian Rift: Implications for magma storage, volatile transport, and rift-related emissions |
| title_short | Spatially variable CO2 degassing in the Main Ethiopian Rift: Implications for magma storage, volatile transport, and rift-related emissions |
| title_sort | spatially variable co2 degassing in the main ethiopian rift implications for magma storage volatile transport and rift related emissions |
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