J. Schlee James M. Robb John C. Behrendt 1974 <div id="Abs1-section" class="c-article-section"><div id="Abs1-content" class="c-article-section__content"><p>PUBLISHED reconstructions of Gondwana continent¹<span>&nbsp;</span>(Fig. l<i>a</i>) show a gap in fit near the junction of the Americas and Africa. To study this critical area, the Unitedgeo I made geophysical measurements and collected rock samples across the continental margin of Liberia (USGS-IDOE cruise leg 5) in November 1971. Figure I<i>b</i><span>&nbsp;</span>indicates the location of the 5,400 km of ship track on a generalised bathymetric map². We shall discuss the data in detail elsewhere. Here we present the evidence for the existence of three fracture zones, two of which have not been reported previously, intersecting the continental margin at the north end of the South Atlantic, which remained closed probably until Cretaceous time. We suggest that Precambrian structures on the African continent controlled the location of these fracture zones. Figure Ic compares gravity and magnetic profiles and interpretations of the seismic profiles for three selected lines (27, 30 and 34) crossing the Grand Cess, Cape Palmas and St Paul fracture zones, respectively.</p></div></div> application/pdf 10.1038/248324a0 en Nature Geophysical evidence for the intersection of the St Paul, Cape Palmas and Grand Cess fracture zones with the continental margin of Liberia, West Africa article