Data/hora: 14/06/2024 20:46:52

Provedor de dados: | 5
País: | France
Título: | The long-term evolution of the Congo deep-sea fan: A basin-wide view of the interaction between a giant submarine fan and a mature passive margin (ZaiAngo project)
Autores: | Anka, Zahie; Seranne, Michel; Lopez, Michel; Scheck-wenderoth, Magdalena; Savoye, Bruno.
Data: | 2009-05
Ano: | 2009
Palavras-chave: | Submarine fan; Lower Congo basin; Submarine canyon; Salt tectonics; Angola escarpment; West Africa Margin.
Resumo: | We have integrated the relatively unknown distal domains of the Lower Congo basin, where the main depocenters of the Congo submarine fan are located, with the better-constrained successions on the shelf and upper slope, through the analysis of thousands of km of 2D seismic reflection profiles off-shore the Congo-Angola passive margin. The basin architecture is depicted by two ca. 800-km-long regional cross sections through the northern (Congo) and southern (Angola) margin. A large unit deposited basinward of the Aptian salt limit is likely to be the abyssal-plain equivalent of the upper-Cretaceous carbonate shelf that characterized the first post-rift deposits in West-equatorial African margins. A latest-Turonian shelf-deepening event is recorded in the abyssal plain as a long period (Coniacian-Eocene) of condensed sedimentation and basin starvation. The onset of the giant Tertiary Congo deep-sea fan in early Oligocene following this event reactivates the abyssal plain as the main depocenter of the basin. The time-space partitioning of sedimentation within the deep-sea fan results from the interplay among increasing sediment supply, margin uplift, rise of the Angola salt ridge, and canyon incision throughout the Neogene. Oligocene-early Miocene turbidite sedimentation occurs mainly in NW-SE grabens and ponded inter-diapir basins on the southern margin (Angola). Seaward tilting of the margin and downslope salt withdrawal activates the up-building of the Angola escarpment, which leads to a northward (Congo) shift of the transfer zones during late Miocene. Around the Miocene-Pliocene boundary, the incision of the Congo submarine canyon confines the turbidite flows and drives a general basinward progradation of the submarine fan into the abyssal plain The slope deposition is dominated by fine-grained hemipelagic deposits ever since. Results from this work contribute to better understand the signature in the ultra-deep deposits of processes acting on the continental margin as well as the basin-wide sediment redistribution in areas of high river input. (C) 2008 Elsevier B.V. All rights reserved.
Tipo: | Text
Idioma: | Inglês

Identificador:

http://archimer.ifremer.fr/doc/2009/publication-6634.pdf

DOI:10.1016/j.tecto.2008.04.009

Editor: | Elsevier
Relação: | http://archimer.ifremer.fr/doc/00000/6634/
Formato: | application/pdf
Fonte: | Tectonophysics (0040-1951) (Elsevier), 2009-05 , Vol. 470 , N. 1-2 , P. 42-56
Fonte: | 2009 Elsevier Ltd All rights reserved.