Noble gases confirm plume-related mantle degassing beneath Southern Africa

Gilfillan, S.M.V. et al. (2019) Noble gases confirm plume-related mantle degassing beneath Southern Africa. Nature Communications, 10, 5028. (doi: 10.1038/s41467-019-12944-6) (PMID:31690720) (PMCID:PMC6831580)

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Southern Africa is characterised by unusually elevated topography and abnormal heat flow. This can be explained by thermal perturbation of the mantle, but the origin of this is unclear. Geophysics has not detected a thermal anomaly in the upper mantle and there is no geochemical evidence of an asthenosphere mantle contribution to the Cenozoic volcanic record of the region. Here we show that natural CO2 seeps along the Ntlakwe-Bongwan fault within KwaZulu-Natal, South Africa, have C-He isotope systematics that support an origin from degassing mantle melts. Neon isotopes indicate that the melts originate from a deep mantle source that is similar to the mantle plume beneath Réunion, rather than the convecting upper mantle or sub-continental lithosphere. This confirms the existence of the Quathlamba mantle plume and importantly provides the first evidence in support of upwelling deep mantle beneath Southern Africa, helping to explain the regions elevation and abnormal heat flow.

Item Type:Articles
Additional Information:S.M.V.G., S.F. and F.M.S. were supported by EPSRC Grant EP/K036033/1; C.E.B. was supported by NERC Grant NE/M007251/1; G.J. was supported by EPSRC Grant EP/P026214/1; R.S.H. was supported by the Scottish Funding Council, EPSRC Grants EP/P026214/1, EP/K000446/2 and NERC Grant NE/L008475/1. The authors would like to acknowledge the financial support of the UK CCS Research Centre (UKCCSRC) to undertake the sampling trip to South Africa. The UKCCSRC is funded by the EPSRC as part of the RCUK Energy Programme. The South African National Energy Development Institute (SANEDI) Stakeholder Engagement team under the South African Centre for Carbon Capture & Storage (SACCCS) are thanked for making the scientific work possible.
Glasgow Author(s) Enlighten ID:Gyore, Dr Domokos and Stuart, Professor Fin
Authors: Gilfillan, S.M.V., Györe, D., Flude, S., Johnson, G., Bond, C.E., Hicks, N., Lister, R., Jones, D.G., Kremer, Y., Haszeldine, R.S., and Stuart, F.M.
Subjects:Q Science > QE Geology
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Nature Communications
Journal Abbr.:Nat. Commun.
Publisher:Nature Research
ISSN (Online):2041-1723
Copyright Holders:Copyright © 2019 The Authors
First Published:First published in Nature Communications 10: 5028
Publisher Policy:Reproduced under a Creative Commons License

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