Tectonics of an incipient oceanic rift (the western extension of the Aden rift within the Gulf of Tadjoura, Republic of Djibouti)

• Published in: Marine geophysical researches 1988-01, Vol.9 (2), p.147-163
• Main Authors: Choukroune, P, Francheteau, J, Auvray, B, Auzende, J M, Brun, J P, Sichler, B, Arthaud, F, Lepine, J C
• Format: Article
• Language: English
• Subjects: Marine
• ISSN: 0025-3235
• DOI: 10.1007/BF00369246

The results of 26 dives with the diving saucer Cyana in the Gulf of Tadjoura and Ghoubbet al Kharab (Republic of Djibouti) are presented. The sites of recent volcanism, tectonics and hydrothermal activity within the axial part of the Gulf of Tadjoura coincide with topographic highs trending at a high angle with respect to the average trend of the axial trough of the Gulf. The highs owe their relief to both volcanism and normal faulting along a trend of 130-140 degree . Recent faulting on the bounding walls of the axial trough is also found along a trend of 130-140 degree where the faults interfere with another set of apparently older faults trending 070 degree parallel to the axial trough. No evidence for transform faulting has been found, in contradiction to all previous kinematic models of the Gulf of Tadjoura. The presently active phase of opening associated with 130-140 degree faults is less than 0.7 my old; there was an older phase associated with 070 degree -080 degree faults creating the main trough of the Gulf.