The Zambezi Sedimentary System (Coastal Plain - Deep Sea Fan) : A Source to Sink Approach
Résumé
We present a new source to sink study of the Zambezi system from the coastal plain to the deep sea fan since early Cretaceous times. Using new seismic data acquired in the Mozambique channel combined with a biochronostratigraphic and paleoclimatic study realised on the cuttings of three industrial wells we provide a new age model in a continuous paleoclimatic frame evolution. The evolution of the Zambezi system may be summarised in four steps : 1) Late Jurassic - Late Cretaceous (Albian): the Zambezi delta is defined by a slight slope with reduced height clinoforms, 2) Late Cretaceous - Cenozoic: the system Zambezi/Limpopo - Save prograded. The location of two main depocentres traduce the distinction of the Limpopo-Save basin from the Zambezi basin at the end of the early Cretaceous and two sedimentary supplies: from the Bushveld and the paleo Zambezi, 3) Early Paleocene - Late Eocene: a main transgression flooded the present day coast allowing the initiation of a carbonate platform, 4) Oligocene - Present day: birth of the modern Zambezi delta with low siliciclastic supply during Oligocene times, increasing during Miocene times linked to the East African Rift System.