Fragmentation and Mesozoic Paleogeography
Fragmentation of Gondwana took place in two phases. Between 190 Ma and 160 Ma, separation followed a line down the eastern flank of the Mozambique Ridge (Dietz and Holden, 1970; Scrutton, 1973b; Kutina, 1975; Du Toit, 1976). This line of fracture paralleled the trend of the Lebombo rhyolites and tholeiitic basalts, a zone of crustal rupture that preceded drift by about 20 Ma (see Chapter 11). Volcanic activity also preceded the separation of South America from Africa and the initiation of the South Atlantic, which took place in the second phase of fragmentation between 135 Ma and 130 Ma (Siedner and Mitchell, 1976; K-Ar). The age of the oldest magnetic anomalies in the Cape Basin west of Cape Town are in close agreement with the Kaokoveld-Serra Geral volcanic activity (Larson and Ladd, 1973).
KeywordsSedimentation Shale Gravel Azimuth Stratigraphy
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