Data/hora: 01/06/2024 08:22:27

Provedor de dados: | 5
País: | France
Título: | Organic-rich sediments in ventilated deep-sea environments: Relationship to climate, sea level, and trophic changes
Autores: | Bertrand, P; Pedersen, Tf; Schneider, R; Shimmield, G; Lallier-verges, E; Disnar, Jr; Massias, D; Villanueva, J; Tribovillard, N; Huc, Ay; Giraud, X; Pierre, C; Venec-peyre, Mt.
Data: | 2003-02
Ano: | 2003
Palavras-chave: | Petroleum source rocks; Coastal upwelling; Deep-sea sediments; Quaternary climate; Southwestern African Margin.
Resumo: | Sediments on the Namibian Margin in the SE Atlantic between water depths of similar to1000 and similar to3600 m are highly enriched in hydrocarbon-prone organic matter. Such sedimentation has occurred for more than 2 million years and is geographically distributed over hundreds of kilometers along the margin, so that the sediments of this region contain a huge concentrated stock of organic carbon. It is shown here that most of the variability in organic content is due to relative dilution by buried carbonates. This reflects both export productivity and diagenetic dissolution, not differences in either water column or bottom water anoxia and related enhanced preservation of organic matter. These observations offer a new mechanism for the formation of potential source rocks in a well-ventilated open ocean, in this case the South Atlantic. The organic richness is discussed in terms of a suite of probable controls including local wind-driven productivity (upwelling), trophic conditions, transfer efficiency, diagenetic processes, and climate-related sea level and deep circulation. The probability of past occurrences of such organic-rich facies in equivalent oceanographic settings at the edge of large oceanic basins should be carefully considered in deep offshore exploration.
Tipo: | Text
Idioma: | Inglês

Identificador:

https://archimer.ifremer.fr/doc/00224/33553/31977.pdf

DOI:10.1029/2000JC000327

https://archimer.ifremer.fr/doc/00224/33553/

Editor: | Amer Geophysical Union
Formato: | application/pdf
Fonte: | Journal Of Geophysical Research-oceans (0148-0227) (Amer Geophysical Union), 2003-02 , Vol. 108 , N. C2 , P. 27.1-27.11

Fonte:

Copyright 2003 by the American Geophysical Union.

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