A revised fit of South America and South Central Africa |
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| Authors: | A Keith Martin Chris JH Hartnady Stephen W Goodlad |
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| Institution: | 1. Marine Geoscience Unit, Department of Geology, University of Cape Town, Rondebosch 7700South Africa;2. Precambrian Research Unit, Department of Geology, University of Cape Town, Rondebosch 7700South Africa |
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| Abstract: | A new set of parameters for the total plate tectonic reconstruction of South America and south central Africa is presented: euler pole 46.75°N, 32.65°W; rotation angle 56.40°. This fit is constrained by at least three pre-drift tectonic features crossing from one continent to the other: (1) the geophysically defined eastern and western boundaries of the submarine Jurassic Outeniqua Basin (South Africa) and the Falkland Plateau Basin; (2) the Late Precambrian transcurrent fault and mylonite belts of Pernambuco (Brazil) and Foumban (West Africa); and (3) the Triassic northern tectonic front of the Cape Fold Belt and the major morphological feature on the Falkland Plateau with which it is closely lined up. Isotopic ages of Falkland Plateau gneisses correspond to Cape Pluton and Cape Fold Belt ages, suggesting their palaeoposition was within the realm of the Cape Fold Belt.In addition, the bathymetrically and geophysically defined northeastern apex of the Falkland Plateau fits into the re-entrant angle defined on the South African margin by the steep southeast-facing sheared Agulhas margin and the southern face of the Tugela Cone. Simultaneously known Precambrian outcrops in northeastern Brazil and in the Gulf of Benin area of West Africa are juxtaposed rather than overlapped. Reconstructions producing a closer fit of these cratonic areas are considered untenable. |
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