Abstract The opening of the South Atlantic Ocean in the Early Cretaceous was only the final stage of the complex rifting process of SW Gondwana. In this contribution, we reassess the chronology of Mesozoic basin formation in southern South America and Africa and integrate it in the long-term rifting and break-up history of SW Gondwana. During the Triassic, after the Gondwanides orogeny, plate-scale instabilities produced intracontinental rifting in Africa, and retro-arc extension on the SW-margin of Gondwana. This process was followed and accentuated by the impingement of the Karoo plume in the Early Jurassic, which triggered rifting in East Africa and ultimately produced the break-up of Eastern from Western Gondwana in the Middle Jurassic. Retro-arc extension continued to affect the palaeo-Pacific margin, with emplacement of the Chon Aike magmatic province in the Patagonian retro-arc during the Early–Middle Jurassic. By the Late Jurassic, retro-arc rifting reached a point of oceanic crust accretion, with the establishment of the Rocas Verdes back-arc basin in southern Patagonia, together with the formation of the Weddell Sea further south, between the South American plate and Antarctica. The core of the Late Paleozoic Gondwanides orogen, between southern South America and Africa, was subjected to oblique rifting at this time and produced the Outeniqua and Rawson/Valdés basins. This area was the locus of extension and oceanization in the Early Cretaceous associated with a rotation of the stress field from NE–SW to east–west extension. The formation of the South Atlantic Ocean resulted from lithospheric extension and was accompanied by extensive intrusive magmatism and extrusive flood basalts identified as seaward dipping reflectors, which were emplaced diachronically from south to north, along different segments along both conjugate margins. These volcanic rocks form the South Atlantic Large Igneous Province. The chronology of the South Atlantic opening and the magmatic sources and processes associated with the formation of seaward dipping reflectors remain interpretative as they have only been studied on seismic data but are still undrilled; hence, scientific drilling will be key to unravel many of these unknowns.

Abstract Compared to other continents, the study of indigenous (non-western) knowledge of palaeontology in Africa is a relatively new field. The literature reviewed here nevertheless suggests a long-lasting string of traditions, geomyths and folklore related to fossilized items on the whole continent and encompassing many African cultures. It is often difficult to estimate the antiquity of these traditions, but the evidence gathered here suggests that they range from the 1800s to pre-colonial times, and up to many millennia. Palaeontological items were collected and used for a variety of reasons, but the African record seems unusual for its scarce use of fossils for traditional medicine. Also, despite substantial efforts, some famous localities with conspicuous fossils still remain without any documented indigenous knowledge. We stress that documenting fossil-related folklore and geomyths is not only a matter of preserving this knowledge or promoting diversity, but is also crucial for establishing strong bonds with local stakeholders to encourage preservation of geoheritage and discover new sites.

Abstract A partially tuned, ‘soft’ seismic reflection, overlying a regional limestone marker on the west African slope, is shown to represent a sequence, up to 30 m thick, within which various individual stratigraphic units are identified, some of which display characteristics of a mass-transport deposit (MTD). The seismic reflection is described in terms of its two-way time structure, reflection amplitude pattern, complex seismic attributes and AVO response. Frequency-dependent aspects of the AVO response, resulting from velocity attenuation and dispersion of seismic signals, are shown to indicate variations in pore-fluid gas concentration. These are exploited to assess lithological, petrophysical and pore-fluid characteristics of the various sub-units within the sequence. A relative acoustic impedance inversion of the seismic data is combined with a low-frequency model, constructed from acoustic velocity data, to approximate absolute acoustic impedance characteristics of the sequence and to model behaviour of the various sub-units across the area. These pseudo-absolute impedance data are combined with evidence from AVO analysis, to construct a 2D model of the MTD unit and to generate a synthetic seismic record, which confirms the interpretation of stratigraphic, petrophysical and lithological properties of the MTD complex.

Abstract Orientated carbonate (calcite twinning strains; n = 78 with 2414 twin measurements) and quartzites (finite strains; n = 15) were collected around Gondwana to study the deformational history associated with the amalgamation of the supercontinent. The Buzios orogen (545–500 Ma), within interior Gondwana, records the high-grade collisional orogen between the São Francisco Craton (Brazil) and the Congo–Angola Craton (Angola and Namibia), and twinning strains in calc-silicates record a SE–NW shortening fabric parallel to the thrust transport. Along Gondwana's southern margin, the Saldanian–Ross–Delamerian orogen (590–480 Ma) is marked by a regional unconformity that cuts into deformed Neoproterozoic–Ordovician sedimentary rocks and associated intrusions. Cambrian carbonate is preserved in the central part of the southern Gondwana margin, namely in the Kango Inlier of the Cape Fold Belt and the Ellsworth, Pensacola and Transantarctic mountains. Paleozoic carbonate is not preserved in the Ventana Mountains in Argentina, in the Falkland Islands/Islas Malvinas or in Tasmania. Twinning strains in these Cambrian carbonate strata and synorogenic veins record a complex, overprinted deformation history with no stable foreland strain reference. The Kurgiakh orogen (490 Ma) along Gondwana's northern margin is also defined by a regional Ordovician unconformity throughout the Himalaya; these rocks record a mix of layer-parallel and layer-normal twinning strains with a likely Himalayan (40 Ma) strain overprint and no autochthonous foreland strain site. Conversely, the Gondwanide orogen (250 Ma) along Gondwana's southern margin has three foreland (autochthonous) sites for comparison with 59 allochthonous thrust-belt strain analyses. From west to east, these include: finite strains from Devonian quartzite preserve a layer-parallel shortening (LPS) strain rotated clockwise in the Ventana Mountains of Argentina; frontal (calcite twins) and internal (quartzite strains) samples in the Cape Fold Belt preserve a LPS fabric that is rotated clockwise from the autochthonous north–south horizontal shortening in the foreland strain site; Falkland Devonian quartzite shows the same clockwise rotation of the LPS fabric; and Permian limestone and veins in Tasmania record a thrust transport-parallel LPS fabric. Early amalgamation of Gondwana (Ordovician) is preserved by local layer-parallel and layer-normal strain without evidence of far-field deformation, whereas the Gondwanide orogen (Permian) is dominated by layer-parallel shortening, locally rotated by dextral shear along the margin, that propagated across the supercontinent.