Stress field during early magmatism in the Ali Sabieh Dome, Djibouti, SE Afar rift

• We dynamically analyzed the brittle deformation of the Ali Sabieh Antiform.
• Paleostress fields show 2 signals: an early E–W extension and later strike-slip.
• Both of them are kinematically coherent.
• We statistically test the variability of the stress inversion on the database.
• Faulting occurred during Oligo-Miocene times in response to magmatic doming.

The so-called Ali Sabieh range, SE Afar rift, exhibits an atypical antiform structure occurring in the overall extensional tectonic context of the Afar triple junction. We dynamically analyzed the brittle deformation of this specific structural high using four different methods in order to better constrain the tectonic evolution of this key-area in the Afar depression. Paleostress inversions appear highly consistent using the four methods, which a posteriori validates this approach. Computed paleostress fields document two major signals: an early E–W extensional field, and a later transcurrent field, kinematically consistent with the previous one. The Ali Sabieh range may have evolved continuously during Oligo-Miocene times from large-scale extensional to transcurrent tectonism, as the result of probable local stress permutation between σ1 and σ2 stress axes.