Aden Ridge

The Aden Ridge is a part of an active oblique rift system located in the Gulf of Aden, between Somalia and the Arabian Peninsula to the north. The rift system marks the divergent boundary between the Somalian and Arabian tectonic plates, extending from the Owen Transform Fault in the Arabian Sea to the Afar Triple Junction or Afar Plume beneath the Gulf of Tadjoura in Djibouti.

The Gulf of Aden is divided east to west into three distinct regions by large-scale discontinuities, the Socotra, Alula Fartak, and Shukra-El Shiek transform faults. Located in the central region, bounded by the Alula Fartak fault and Shukra-El Shiek fault, is the Aden spreading ridge. The Aden Ridge connects to the Sheba Ridge in the eastern region and to the Tadjoura Ridge in the western region. Due to oblique nature of the Aden Ridge, it is highly segmented. Along the ridge there are seven transform faults that offset it to the north.

Extension of the Gulf of Aden rift system began in the late Eocene - early Oligocene (~35 Ma ago), caused by the northeast escape of the Arabian plate from the African plate at a rate of ~2 cm/yr, and the development of the Afar plume. Extension eventually gave way to seafloor spreading, first initiated near the Owen transform fault ~18 Ma ago. Seafloor spreading then propagated as far west as the Shukra-El Shiek fault at a rate of ~14 cm/yr ~6 Ma ago rifting propagated west of the Shukra-El Shiek fault until terminating at the Afar plume. The Afar plume is believed to have contributed to the initiation of the Aden ridge, due to the flow of hot mantle material being channeled along the thin lithosphere beneath the Gulf of Aden. Currently, the Aden Ridge is undergoing extension at a rate of ~15 mm/yr.

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