Seismic patterns of a muddy contourite fan (Vema Channel, South Brazilian Basin) and a sandy distal turbidite deep-sea fan (Cap Ferret system, Bay of Biscay): a comparison
Faugeres, J.-C.; Imbert, P.; Mézerais, M.L.; Crémer, M. (1998). Seismic patterns of a muddy contourite fan (Vema Channel, South Brazilian Basin) and a sandy distal turbidite deep-sea fan (Cap Ferret system, Bay of Biscay): a comparison. Sediment. Geol. 115(1-4): 81-110. https://dx.doi.org/10.1016/s0037-0738(97)00088-2 In: Sedimentary Geology. Elsevier: Tokyo; Oxford; New York; London; Amsterdam. ISSN 0037-0738; e-ISSN 1879-0968, more |  |
| Keywords | Geological time > Phanerozoic > Geological time > Cenozoic > Quaternary
Geological time > Phanerozoic > Geological time > Cenozoic > Tertiary > Cenozoic > Neogene
ANE, Biscay Bay [Marine Regions]
| | Author keywords | contourite drift; distal deep-sea fan; seismic patterns; S. Brazilian Basin |
| Authors | | Top | Datasets | - Faugeres, J.-C.
- Imbert, P.
- Mézerais, M.L.
- Crémer, M.
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| Abstract | The aim of this paper is to discriminate the depositional facies, geometries and mechanisms of deposition of contouritic fans from those of turbidite distal fans, with a view to provide better resolution of reservoir prediction. Two examples are analysed: the Vema contouritic drift in the South Brazilian Basin and the Cap Ferret turbiditic fan in the Bay of Biscaye. The Vema contourite fan is a Neogene mud-rich accumulation (200–400 m thick), fed by Antarctic Bottom Water bottom currents and located downstream of the Rio Grande Rise. It forms one single-mound fan-shaped body in between two major channels, and where the main part of the deep circulation is funnelled into. As a result of the morphological and hydrological background, the comourite drift progrades mostly downstream. The accumulation was built as several depositional units (‘channel-levee’ systems) bounded by widespread discontinuities showing erosional patterns. This resulted from episodes of strong and/or unstable current activity producing the discontinuities, alternating with periods of relatively weak and stable currents and major deposition. The Pliocene-Quaternary Cap Ferret distal deep-sea fan is a thick (500 m) sand-rich turbiditic accumulation fed directly by an uplifting mountain range. The accumulation is developed downstream of a main turbiditic feeder channel and the volume of sediment involved is much higher than for the Vema contourite fan. It shows a complex network of shallow channels and low-relief levees which merge downstream into thin, sandy, sheet-like deposits. Several depositional units are stacked vertically. Each unit is built by the lateral migration of a ‘channel-levee’ system. The stacking pattern of the successive units is prograding towards the basin. The presence of major discontinuities cutting throughout a whole accumulation, and the fairly irregular geometry of the ‘channel-levee’ deposits (absence of any obvious migrating trend), appear to be the most distinctive features of a contourite fan. On the other hand, the lateral migration of the ‘channel-level’ geometries and the presence of erosional surfaces of limited extent and restricted to the channels, are the main diagnostic features of a distal turbidite fan. Otherwise the seismo-facies are fairly similar in both sedimentary bodies. |
| Datasets (2) | - Flanders Marine Institute; Renard Centre of Marine Geology - Ugent (2018). Global contourite distribution database, version 2. Available online at https://www.marineregions.org, more
- Flanders Marine Institute; Renard Centre of Marine Geology - Ugent (2019). Global contourite distribution database, version 3. Available online at https://www.marineregions.org, more
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