--> Abstract: Long-term Evolution of the Congo Deep-sea Fan and Investigation on Potential Source Rocks in the Ultra-deep Offshore of the Gulf of Guinea, by Zahie Anka, Michel Séranne, Rolando Di Primio, and Magdalena Scheck-Wenderoth; #90072 (2007)

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Long-term Evolution of the Congo Deep-sea Fan and Investigation on Potential Source Rocks in the Ultra-deep Offshore of the Gulf of Guinea

Zahie Anka1, Michel Séranne2, Rolando Di Primio3, and Magdalena Scheck-Wenderoth1
1GeoForschungsZentrum Potsdam (GFZ), 14473 Potsdam, Germany
2CNRS - Université Montpellier, 34095 Montpellier, France
3GeoForschungsZentrum Potsdam, D-14473 Potsdam, Germany

Although the Congo-Angola margin has been extensively explored, most of the work has been concentrated in the slope and shelf areas, and thus far from the Congo fan major oceanic depocenters. Our approach is based upon the analysis of more than 19,000 km 2-D multi-channel seismic reflection profiles from the ZaiAngo dataset, which cover the ultra-deep off-shore domains, thus the outer slope and abyssal plain, of the Congo deep-sea fan.
Our main results suggest that:
- From Albian to Turonian an older deep-sea fan, with thickness up to 2.5 km, was deposited onto the young oceanic crust and extends for more than 200 km seawards of the present day base of the slope. This fan could have been fed by a source close to present-day Congo River.
- The onset of the tertiary Congo deep-sea fan takes place in early Oligocene, after a long period of basin starvation during late Cretaceous- Eocene. This fan extends into the ultra deep-domains for more than 500 km seawards of the present-day base of the slope.
- From Neogene up to Recent, there is a general progradation of the system caused by the interaction among climate, the development of the Angola's escarpment (related to the salt tectonics characteristic of the area) and margin tectonic uplift.
- Continuous Neogene sediment influx has influenced the growth of a massif salt domain and the Angola's escarpment. In turn, these latter have controlled the location of deep-sea fan depocenters and the overall basinward progradation of the fan in late Miocene- early Pliocene.
These findings complement the ones in the adjacent inner slope/continental margin and will be incorporated in further thermal modeling in order to explore the source rock potential of these distal sequences.

 

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece