Title:
Conjugate margins of the South Atlantic: Namibia-Pelotas
Publication Year:
2012
Abstract:
The Namibian continental margin is a type example of a volcanic margin, and forms the conjugate to the volcanic margin of the Pelotas Basin, southern Brazil. The margin is segmented, and the structural pattern of the segmentation is related to fundamental elements of the basement structure. The dominant structural feature of the margin is the hinge zone separating the almost unrifted continental crust onshore from the thinned continental and transitional crust offshore. Seaward of the hinge zone, prolific occurrences of dipping reflector sequences are mapped along the entire margin, although they are best developed in the north, in the Walvis Basin. The central and southern parts of the margin consist of two other major depocentres, the Luderitz and Orange Basins. Breakup occurred at around 130 Ma, coinciding with the extrusion of the Etendeka Group flood basalts. Post-rift subsidence of the margin commenced in the mid-Cretaceous, and the shelf slope system prograded and aggraded until the end of the Cretaceous, when uplift of the interior changed the dynamics of the margin. Limited shelf subsidence occurred during the Cenozoic, with most sediment accumulation occurring on the slope. Keywords: namibia, passive margin, stratigraphy, structure, breakup.
Publication Title:
Regional Geology and Tectonics: Phanerozoic Passive Margins, Cratonic Basins and Global Tectonic Maps
Pages:
202-221
Item Type:
Book or Magazine Section
Language:
en

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