The amount of carbon dioxide seeping out of the Earth’s surface is poorly understood. Magma carries dissolved carbon dioxide from the deep earth towards the surface, where it is released and travels along fractures in the crust.
Research by Oxford Earth Sciences DPhil student Jonathan Hunt (Worcester 2011, Univ 2015), working with supervisors Tamsin Mather and David Pyle, Deep Carbon collaborator Pete Barry, and Addis Ababa University researcher Amdemichael Zafu, attempts to quantify this phenomenon in central Ethiopia, where a continental rift is splitting one tectonic plate in two. A similar study undertaken in Kenya and Tanzania suggested that the flow of carbon dioxide through the East African Rift was much larger than previously thought. Hunt and the team undertook new surveys and found that it varies greatly, which makes estimating a total flow through the rift very difficult. By compiling the locations and distribution of hot springs and volcanic vents, the researchers were able to extrapolate from where heat and carbon dioxide come to the surface to provide a new estimate. The results suggest that the East African Rift releases less carbon dioxide than was thought from Kenya and Tanzania, but still a substantial amount. If the rift does emit as much carbon dioxide as suggested, either more carbon is below the crust in East Africa than initially thought or more magma is involved.
Jonathan will be featured in an interview with the Deep Carbon Observatory in coming weeks.
The paper ‘Spatially Variable CO2 Degassing in The Main Ethiopian Rift: Implications For Magma Storage, Volatile Transport And Rift-Related Emissions’ is published in G3: Geochemistry, Geophysics, Geosystems. DOI: