Nature 319, 396 - 399 (30 January 1986); doi:10.1038/319396a0

Tectonics of the westernmost Gulf of Aden and the Gulf of Tadjoura from submersible observations

Cyaden Scientific Team: P. Choukroune^*, B. Auvray^*, J. Francheteau^†, J. C. Lepine^†, F. Arthaud^‡, J. P. Brun^§, J. M. Auzende, B. Sichler & Y. Khobar

^*University of Rennes, 35042 Rennes Cedex, France
^†IPG, Paris, University of Paris. 7, 75230 Paris Cedex 05, France
^‡University of Montpellier, 34060 Montpellier Cedex, France
^§University of Paris 7, 75230 Paris Cedex 05, France
IFREMER, 29273 Brest Cedex, France
ISERT, Djibuti, Republic of Djibuti

The Gulf of Tadjoura, separating the Danakil and Somalia plates¹, represents the western extension of the Sheba Ridge between Arabia and Somalia in the Gulf of Aden (Fig. 1). It has been assumed that a simple plate-tectonic scheme could be applied to the area with NE−SW transform faults offsetting roughly east−west zones of accretion represented by the major bathymetrie troughs¹⁻⁸ (Fig. 1c). More recently this boundary has been interpreted as a westward-propagating rift with its present-day tip on land in the region of the Asal Lake^9,10. Here we present data from dives with the submersible Cyana which show that there have been two episodes of extensional faulting, an older inactive phase parallel to the general ENE−WSW direction of the gulf and a younger fault set along discontinuous zones striking 140°. There is no surface evidence for any transform fault zone in the area covered and the incipient spreading segments whose geometry implies extension on 050° do not define a plate boundary. The faulting observed is at odds with that predicted by orthodox plate tectonics.

1. Le Pichon, X. & Francheteau, J. Tectonophysics 26, 369−406 (1978). | Article |
2. Barberi, F. & Varet, J. Bull. geol. Soc. Am. 88, 1251−1266 (1977). | ChemPort |
3. Lepine, J. C., Ruegg, J. C. & Anis, A. M. Bull. Soc. géol. Fr. 22, 809−816 (1980).
4. Arthaud, F., Choukroune, P. & Robineau, B. Bull. Soc. géol. Fr. 22, 901−908 (1980).
5. Arthaud, F., Choukroune, P. & Robineau, B. Bull. Soc. géol. Fr. 22, 909−915 (1980).
6. Needham, H. D. et al. Earth planet. sci. Lett. 28s, 439−453 (1976). | Article | ISI |
7. Laughton, A. S., Whittmarsh, R. N. & Jones, M. T. Phil. Trans. R. Soc. A267, 227−266 (1970). | ISI |
8. Girdler, R. W., Brown, C., Moy, D. J. M. & Styles, P. Phil. Trans. R. Soc. A298, 1−43 (1980). | ISI |
9. Courtillot, V., Galdeano, A. & Le Mouel, J. L. Earth planet. Sci. Lett. 47, 144−160 (1980). | Article | ISI |
10. Courtillot, V. Phys. Earth planet. Inter. 21, 343−350 (1980). | Article | ISI |
11. Stieljes, L., Joron, J. L., Treuil, M. & Varet, J. Bull. Soc. géol. Fr. 17, 851−862 (1976).
12. Peter, G. & de Wald, O. Bull geol. Soc. Am. 80, 2313−2316 (1969).
13. Backer, H., Clin, N. & Lange, K. Mar. Geol. 15, 309−327 (1973). | Article | ISI |
14. Olausson, E. & Olson, I. U. Palaeogr. Palaeoclimatol. Palaeocol. 6, 87−103 (1969). | Article | ChemPort |
15. Richard, O. thesis., Univ. Orsay (1979).
16. Lepine, J. C., Richard, O., Ruegg, J. C., Treuil, M. & Varet, J. Cr. hebd. Séanc. Acad. Sci., Paris 283, 9−12 (1976).
17. Juteau,, Th. et al. Bull. Cent. Rech. expl. Prod. Elf-Aquitaine 7, 1, 217−231 (1980).
18. Zonenshain, L. P., Monin, A. S. & Sorokhtin, O. G. Geotektonika 2, 3−22 (1981) (in Russian).
19. Minster, J. B. & Jordan, T. H. J. geophys. Res. 83, 5331−5354 (1978). | ISI |
20. Monin, A. S. et al. Deep Sea Res. 29, 361−373 (1982). | Article | ISI |