A discussion on the structure and evolution of the Red Sea and the nature of the Red Sea, Gulf of Aden and Ethiopia rift junction - The evolution of the Gulf of Aden

Abstract

Marine geological and geophysical data from the International Indian Ocean Expedition, especially from cruise 16 of R. R. S. Discovery , have made it possible to prepare new charts of the bathymetry and the magnetic anomaly field which, together with other data, enable the evolutionary history of the Gulf of Aden to be worked out. Over the past 10 Ma the theory of seafloor spreading can account satisfactorily for the features of the Sheba Ridge and provides evidence of spreading rates in the direction of the fracture zones varying from 0.9 cm a ^-1 per limb in the west to 1.1 cm a ^-1 per limb in the east. Between the initial creation of the Gulf and 10 Ma ago, the evolution is less certain, although the geophysical evidence indicates that the crustal structure of the Gulf outside the Sheba Ridge is oceanic.