Crustal thickness of Egypt determined by gravity data

The observed Bouguer gravity anomalies of Egypt and surrounding areas have been analysed in terms of the gravity field components due to the lower crust-upper mantle interface (Moho). Band-pass filtering of the observed field in the wavelength band 300 < lambda < 700 km has been assumed to be related to the variable crustal thickness of the area. Seven gravity profiles were chosen and interpreted in terms of 2.5D models. These profiles were constrained by structural sections based on previous seismic survey interpretations from the northern Red Sea and adjoining continental crust. A mean density of 3.30 g cm(-3) was used for the upper mantle and a density of 2.90 g cm(-3) was given to the lower crust. The density of the mantle upwelling assumed for the Red Sea area was 3.15 g cm(-3). The result of the 2.50 gravity modelling allowed the construction of a map showing the depth variation of the interface between the upper mantle and the lower crust of Egypt. (C) 1997 Elsevier Science Limited.