Crustal section of the whole conjugate margins of the eastern Gulf of Aden from seismic data, 2-D gravity modelling of the ES12 and ES26 profiles (2-D gravity model of this study, Fig. 10b) and refraction data (Laughton & Tramontini 1969). The onshore domain with only scattered refraction data is colourless. The sections have been fitted just before the emplacement of the Sheba Ridge. See map inset reconstructed at anomaly A5d for location, vertical exaggeration ×4.