Gravity Measurements in the North-eastern Sudan and Crustal Structure of the Red Sea

Gravity measurements made in the Sudan over a part of the Red Sea coastal plain and along a profile between Atbara and Suakin are described. Bouguer anomalies over the coastal plain are similar to those observed at continental margins off north-east America. These anomalies, taken together with those observed by other workers and corrected for shallow density variations, show the existence of a regional anomaly with a maximum at about + 140 mgal over the Red Sea axis and a minimum at about −82 mgal over the Red Sea Hills. Assuming symmetry about the axis, the regional anomaly is interpreted in terms of two crustal models. Feasibility and significance of these models is discussed in the light of other geophysical information. It is concluded that a separation in the axial trough of the Red Sea was preceded by a drastic thinning of the continental crust.