ORIGINAL RESEARCH article
Front. Earth Sci.
Sec. Volcanology
Volume 13 - 2025 | doi: 10.3389/feart.2025.1575660
Melt generation and evolution in the Adda'do rift segment of the Afar rift from trace elements and petrography
Provisionally accepted
- 1University of Southampton, Southampton, United Kingdom
- 2Environment Agency (United Kingdom), Rotherham, United Kingdom
- 3Swansea University, Swansea, Wales, United Kingdom
- 4University of Pisa, Pisa, Tuscany, Italy
- 5University of Florence, Florence, Tuscany, Italy
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
Along-rift variations in the stage of continental separation are observed in the northern East African Rift System (EARS), from magma-assisted continental rifting in the Main Ethiopian Rift (MER) to nascent oceanic spreading in Afar. However, the implications on spatial and temporal changes in mantle melting and melt evolution remain poorly understood. Given that the EARS is the longest and best-exposed example of continental rifting in the world, the MER and Afar are an ideal place to investigate magmatism and volcanism in late-stage continental rifts. Here, we focus on the Adda’do Magmatic Segment (AMS) in the northernmost sector of the MER, that has experienced the most prolonged lithospheric thinning. We present new trace element data and petrographic observations from around 50 samples, and combine these with geochemical modelling to investigate depth of melt origin and melt evolution, in the AMS. Using mixing modelling of garnet lherzolite and spinel lherzolite mantle peridotite sources, we show that the AMS magmas are produced from a relatively deep source with 10–60% garnet lherzolite, corresponding to depths of around 85 km, and generated by approximately 4–9.5% partial melting of the mantle. We find no significant variation of these characteristics with either sample age or sample location at the AMS, suggesting no systematic temporal variations occurred in either the depth or the degree of melting within a single magmatic segment. However, on a regional scale, depth of melting is between that interpreted for the MER and northern Afar, implicating the stage of rift evolution and consequent degree of lithospheric thinning as a major control. MELTS modelling of the samples indicates that the observed variations in sample compositions in the AMS can be explained predominantly by fractional crystallisation, with negligible crustal contamination in the basaltic samples. Crustal contamination may play a greater role in the composition of intermediate and evolved samples in the AMS.
Keywords: Trace Elements, AFAR, volcano, rift, geochemistry
Received: 12 Feb 2025; Accepted: 14 Jul 2025.
Copyright: © 2025 Rees, Watts, Gernon, Taylor, Pagli and Keir. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Derek Keir, University of Southampton, Southampton, United Kingdom
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.