The importance of past rifting in large igneous province development
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Lithospheric thin zones, such as recently-failed rifts, are generally assumed weak spots where magmatism and deformation can concentrate during rifting and large igneous province development¹¯³. Yet, the Turkana Depression in East Africa, site of the failed 66 Ma Anza Rift, did not experience the widespread flood magmatism seen on the adjacent Ethiopian Plateau, despite being a lithospheric thin-spot when the region encountered hot plume material ca. 45 Ma⁴. Here, we jointly invert surface-wave and receiver function data to constrain crustal and upper-mantle seismic structure below the Depression to evaluate lithospheric thermo-mechanical modification. Evidence for thick lower-crustal intrusions, ubiquitous below the uplifted Ethiopian Plateau⁵;⁶, is comparatively lacking below the Depression’s failed Anza Rift system, which ongoing East African rifting is circumnavigating, not exploiting. The mantle lithosphere below the Depression has also retained its cool, fast wavespeed ‘lid’ character, contrasting the Ethiopian Plateau. Volatile depletion during failed Anza rifting likely rendered the thinned lithosphere refractory without later rejuvenation. Subsequent rifting and magmatism thus initiated away from the still-thin Anza Rift, in regions where fertile lithosphere enabled melting and the sufficient lowering of plate yield strength. Areas of thinned lithosphere are thus not necessarily persistent weak zones where significant extension and magmatic provinces will develop.
Date Issued
2025-11-06
Date Acceptance
2025-09-23
Citation
Nature, 2025, 647, pp.115-120
ISSN
0028-0836
Publisher
Nature Research
Start Page
115
End Page
120
Journal / Book Title
Nature
Volume
647
Copyright Statement
© The Author(s) 2025. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
License URL
Identifier
10.1038/s41586-025-09668-7
Publication Status
Published
Date Publish Online
2025-11-05