Journal article
Middle to late Pleistocene palaeoceanography inferred from ridge-furrow structures on the continental slope offshore Angola
- Abstract:
- 3D seismic reflection data have been used to map 784 enigmatic ridge-furrow structures in water depths of 0.8–1.7 km offshore Angola. The structures are characterised by asymmetric ridges with intervening furrows, typically <0.5–5.5 km long, with a sinuous to bifurcating planform. The furrows are well-imaged on seismic profiles, and range from 60 to 80 m in width, up to 10 m in amplitude, and 0.1–1 km in wavelength. The furrow sets aggrade in a downslope direction and occur in arrays that have an internally consistent direction that is either parallel, or slightly diverging or converging. Two alternative origins are considered: (1) furrows that are dominantly erosional scours formed from seafloor-incising currents flowing parallel to the furrows, with the ridges a by-product of the erosion, or (2) the ridge-furrows are bottom-current generated dune-type sediment waves. The latter interpretation allows us to reconstruct a key component of the deepwater bottom-currents regime along this continental margin from the Middle Pleistocene to the present-day. The most likely transport agent responsible for the interpreted sediment waves is a palaeo-bottom-current regime with a flow direction toward the west-southwest/south-southwest, the same direction of the sediment wave migration. The palaeo-bottom currents would then be expected to have a very specific flow regime with 1 < Frmax < 2 and may originate from longshore currents cascading off the shelf, Congo Canyon distal overflows, breaking internal waves or a combination of these processes.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
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(Preview, Accepted manuscript, 7.3MB, Terms of use)
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- Publisher copy:
- 10.1016/j.margeo.2021.106562
Authors
- Publisher:
- Elsevier
- Journal:
- Marine Geology More from this journal
- Volume:
- 439
- Article number:
- 106562
- Publication date:
- 2021-07-09
- Acceptance date:
- 2021-07-04
- DOI:
- ISSN:
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0025-3227
- Language:
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English
- Keywords:
- Pubs id:
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1187509
- Local pid:
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pubs:1187509
- Deposit date:
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2021-07-26
Terms of use
- Copyright holder:
- Elsevier B.V.
- Copyright date:
- 2021
- Rights statement:
- © 2021 Elsevier B.V. All rights reserved.
- Notes:
- This is the accepted manuscript version of the article. The final version is available online from Elsevier at: https://doi.org/10.1016/j.margeo.2021.106562
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