Magnetic anomalies of the northern and southern domains of the study area superimposed on total magnetic field (200 nT contours). The structural interpretation of the offshore margins is from d'Acremont (2005) and of the onshore margins from Beydoun & Bichan (1969), Birse (1997), Brannan (1997), Lepvrier (2002), Bellahsen (2006). (i), (ii) and (iii) used to enumerate the domains are explained in the text.