Spatially Variable CO2 Degassing in the Main Ethiopian Rift: Implications for Magma Storage, Volatile Transport, and Rift-Related Emissions

摘要: Deep carbon emissions from historically inactive volcanoes, hydrothermal, and tectonic structures are among the greatest unknowns in long-term (∼Myr) cycle. Recent estimates of diffuse CO2 flux Eastern Rift East African System (EARS) suggest this could equal entire mid-ocean ridge system. We report new surveys Main Ethiopian (MER, northernmost EARS), reassess rift-related flux. Since degassing MER is concentrated discrete areas volcanic off-edifice activity, characterization such important for extrapolation to a rift-scale budget. Locations hot springs fumaroles along rift show numerous geothermal away edifices. With these data, we estimate total central northern as 0.52–4.36 Mt yr−1. Our extrapolated 3.9–32.7 Mt yr−1 CO2, overlapping with lower end range presented recent estimates. By scaling, that 6–18 can be accounted by magmatic extension, which implies an role volatile-enriched lithosphere, crustal assimilation, and/or additional intrusion account upper results also have implications nature volcanism MER. Many found >10 km nearest center, suggesting ongoing hazards associated regional volcanism.