Role of metasomatism in the development of the East African Rift at the Northern Tanzanian Divergence: insights from 3D magnetotelluric modeling

Sinan Özaydın*, Kate Selway, Stephen F. Foley, Isra S. Ezad, William L. Griffin, Pascal S. Tarits, Sophie Hautot

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)
9 Downloads (Pure)

Abstract

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 modeling 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.

Original languageEnglish
Article numbere2023GC011191
Pages (from-to)1-19
Number of pages19
JournalGeochemistry, Geophysics, Geosystems
Volume25
Issue number1
Early online date24 Jan 2024
DOIs
Publication statusPublished - Jan 2024

Bibliographical note

Copyright the Author(s) 2024. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

Keywords

  • craton
  • East African Rift
  • magnetotellurics
  • metasomatism
  • rifting
  • Tanzania

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