Structure of the Red Sea at 20° N from gravity data and its implication for continental margins

Recent gravity data have enabled a gravity profile extending 1,500 km over Nubia, the Red Sea and Arabia to be compiled. Using a modal value of -48 mGal for the Bouguer anomaly over Africa away from regions of rifting we have determined the way in which the lithosphere thins and breaks to form the Red Sea. We find that nearly the whole of the Red Sea from coast to coast is probably underlain by oceanic crust and the regions of thinning extend for ∼120 km landwards of the Nubian coast and 180 km landwards of the Arabian coast. This implies that for continental margins similar to those of the Red Sea, the vast thicknesses of sediments might be underlain by early oceanic lithosphere rather than by thinned and down-faulted continental lithosphere.