loading page

Role of metasomatism in the development of the East African Rift at the Northern Tanzanian Divergence: Insights from 3D magnetotelluric modelling.
  • +4
  • Sinan Özaydin,
  • Kate Selway,
  • Stephen Foley,
  • Isra Ezad,
  • William L. Griffin,
  • Pascal Tarits,
  • Sophie Hautot
Sinan Özaydin
University of Sydney

Corresponding Author:[email protected]

Author Profile
Kate Selway
University of Tasmania
Author Profile
Stephen Foley
Maquarie University
Author Profile
Isra Ezad
(6) Macquarie University, Department of Earth and Environmental Sciences
Author Profile
William L. Griffin
ARC Centre of Excellence for Core to Crust Fluid Systems and GEMOC, Macquarie University
Author Profile
Pascal Tarits
Laboratoire Geoscience Ocean, Plouzané
Author Profile
Sophie Hautot
Author Profile


The Northern Tanzanian Divergence in the East Africa Rift is arguably the best place on Earth to study the controls on rifting of thick lithosphere. Here, where the East Africa Rift intersects the Tanzanian Craton and the Mozambique Belt, the relationships between volcanism, faulting, pre-existing structures and lithospheric thickness and composition can be observed. In this work, we carry out the first lithospheric-scale 3D magnetotelluric modelling of the Northern Tanzanian Divergence and combine the results with experimental electrical conductivity and petrology models to calculate mantle composition, which is also inferred in the craton from reanalysis of garnet xenocryst data. Our results show that metasomatic materials exist in the cratonic lithospheric mantle and the relatively undeveloped southern part of the rift zone. However, the lithospheric mantle of the Mozambique Belt and the more developed northern section of the rift is more resistive and does not contain metasomatic phases. Combined with geochemical data from erupted lavas, these results suggest that, in zones that have experienced voluminous Cenozoic magmatism, melting events have destroyed the metasomes and dehydrated the mantle. Since the presence of magma is a primary control of lithospheric strength, rifting may become limited as the lithospheric mantle becomes dehydrated and harder to melt.
16 Aug 2023Submitted to ESS Open Archive
17 Aug 2023Published in ESS Open Archive