Large-scale flexuring and antithetic extensional faulting along a nascent plate boundary in the SE Afar rift

Bernard Le Gall (1) , Mohamed Ahmed Daoud (2) , Joël Rolet (1) , Nima Moussa Egueh (1, 2)

1 LDO - Domaines Océaniques
2 Institut Des Sciences de la Terre

New structural data from the SE Afar margin in Djibouti lead us to discriminate two recent (<1 Ma) extensional fault networks between the Afar accreted crust, and the South Danakil block to the east. Emphasis is placed on the N-S-oriented Makarassou fault system which dissects the prominent westward-(riftward-)facing topographic flexure between the two structural domains. The most striking characteristic of the Makarassou fault belt is a closely spaced network of continentward-dipping extensional faults, bounding domino blocks of 3-1 Ma tilted lavas of the Stratoid series. The Makarassou fault-flexure system is interpreted as an extensional faulted monocline that developed in response to differential subsidence and crustal downwarping of the Afar magmatically accreted transitional crust. Large-scale flexuring and associated structures along the eastern flank of the Asal-Manda-Inakir incipient plate boundary are regarded as indicative of a nascent volcanic rifted margin in SE Afar.

Domains: Tectonics; Global Changes

Bernard Le Gall, Mohamed Ahmed Daoud, Joël Rolet, Nima Moussa Egueh. Large-scale flexuring and antithetic extensional faulting along a nascent plate boundary in the SE Afar rift. Terra Nova, 2011, 23 (6), pp.416-420. ⟨10.1111/j.1365-3121.2011.01029.x⟩. ⟨insu-00635012⟩