On the termination of deep-sea fan channels: Examples from the Rhone Fan (Gulf of Lion, Western Mediterranean Sea)

The termination of a deep-sea turbiditic channel represents the ultimate sink of terrigenous sediment in the oceans or lakes. Such environment is characterized by rapid slope decrease and by loss of confinement of turbidity currents. It results in the deposition of Channel-Mouth-Lobes that can be se...

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Autores: Droz, L., Jegou, I, Gillet, H., Dennielou, B., Bez, M., Canals Artigas, Miquel, Amblàs i Novellas, David, Lastras Membrive, Galderic, Rabineau, Marina
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2020
País:España
Institución:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/211140
Acceso en línea:https://hdl.handle.net/2445/211140
Access Level:acceso abierto
Palabra clave:Geologia submarina
Mediterrània (Mar)
Submarine geology
Mediterranean Sea
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spelling On the termination of deep-sea fan channels: Examples from the Rhone Fan (Gulf of Lion, Western Mediterranean Sea)Droz, L.Jegou, IGillet, H.Dennielou, B.Bez, M.Canals Artigas, MiquelAmblàs i Novellas, DavidLastras Membrive, GaldericRabineau, MarinaGeologia submarinaMediterrània (Mar)Submarine geologyMediterranean SeaThe termination of a deep-sea turbiditic channel represents the ultimate sink of terrigenous sediment in the oceans or lakes. Such environment is characterized by rapid slope decrease and by loss of confinement of turbidity currents. It results in the deposition of Channel-Mouth-Lobes that can be separated from the channel mouth by an erosional (scoured) or by-pass dominated Channel-Lobe Transition Zone. Several factors can control the occurrence, extent and morphologic expression of the area such as the slope break angle, the upslope and downslope angle and the mud/sand ratio in flows. Disentangling these factors remains challenging due to the scarcity of outcrops and to the usual faint morphologies and low thickness of deposits. With bathymetric and seismic data we calculated the morphometric parameters of 8 channel-levees and their Channel-Mouth Lobes from the deepest area of the Rhone fan, a mud-sand rich system, and among which the youngest one (called neofan) was deposited at the end of the Last Glacial Maximum between 21.5 and 18.3 ka cal. BP. Emplacement and shape (finger-shaped or pear-shaped bulges) of Channel-Mouth Lobes is controlled by the seabed morphology (adjacent channel-levees and salt diapirs). A less prominent morphology of the neofan is attributed to premature quiescence related to the post sea-level rise sediment starvation. We show that the occurrence and expression of a Channel-Lobe Transition Zone is controlled by the gradient upstream of the channel mouth slope break. The extended Channel-Lobe Transition Zone and detached lobe of the neofan are attributed to the high upslope gradient (0.26°) while the less detached or attached lobes of other channel-levees is attributed to lower upslope gradient (0.13°). We show that scouring and scours concatenation into flutes at the Channel-Lobe Transition Zone is a major driver for the inception of channels and further confinement of turbidity current. For the first time we show that concatenation of scours in shingled disposition developed an incipient channel sinuosity at this very early stage of channel development. The channel-levee can extend downslope nearly instantaneously by tens of kilometers when isolated nascent channels connect to the channel mouth.Elsevier B.V.2020info:eu-repo/semantics/articleinfo:eu-repo/semantics/acceptedVersionapplication/pdfhttps://hdl.handle.net/2445/211140Articles publicats en revistes (Dinàmica de la Terra i l'Oceà)reponame:Dipòsit Digital de la UBinstname:Universidad de BarcelonaInglésVersió postprint del document publicat a: https://doi.org/10.1016/j.geomorph.2020.107368Geomorphology, 2020, vol. 369https://doi.org/10.1016/j.geomorph.2020.107368(c) Elsevier B.V., 2020info:eu-repo/semantics/openAccessoai:diposit.ub.edu:2445/2111402026-05-27T06:46:51Z
dc.title.none.fl_str_mv On the termination of deep-sea fan channels: Examples from the Rhone Fan (Gulf of Lion, Western Mediterranean Sea)
title On the termination of deep-sea fan channels: Examples from the Rhone Fan (Gulf of Lion, Western Mediterranean Sea)
spellingShingle On the termination of deep-sea fan channels: Examples from the Rhone Fan (Gulf of Lion, Western Mediterranean Sea)
Droz, L.
Geologia submarina
Mediterrània (Mar)
Submarine geology
Mediterranean Sea
title_short On the termination of deep-sea fan channels: Examples from the Rhone Fan (Gulf of Lion, Western Mediterranean Sea)
title_full On the termination of deep-sea fan channels: Examples from the Rhone Fan (Gulf of Lion, Western Mediterranean Sea)
title_fullStr On the termination of deep-sea fan channels: Examples from the Rhone Fan (Gulf of Lion, Western Mediterranean Sea)
title_full_unstemmed On the termination of deep-sea fan channels: Examples from the Rhone Fan (Gulf of Lion, Western Mediterranean Sea)
title_sort On the termination of deep-sea fan channels: Examples from the Rhone Fan (Gulf of Lion, Western Mediterranean Sea)
dc.creator.none.fl_str_mv Droz, L.
Jegou, I
Gillet, H.
Dennielou, B.
Bez, M.
Canals Artigas, Miquel
Amblàs i Novellas, David
Lastras Membrive, Galderic
Rabineau, Marina
author Droz, L.
author_facet Droz, L.
Jegou, I
Gillet, H.
Dennielou, B.
Bez, M.
Canals Artigas, Miquel
Amblàs i Novellas, David
Lastras Membrive, Galderic
Rabineau, Marina
author_role author
author2 Jegou, I
Gillet, H.
Dennielou, B.
Bez, M.
Canals Artigas, Miquel
Amblàs i Novellas, David
Lastras Membrive, Galderic
Rabineau, Marina
author2_role author
author
author
author
author
author
author
author
dc.subject.none.fl_str_mv Geologia submarina
Mediterrània (Mar)
Submarine geology
Mediterranean Sea
topic Geologia submarina
Mediterrània (Mar)
Submarine geology
Mediterranean Sea
description The termination of a deep-sea turbiditic channel represents the ultimate sink of terrigenous sediment in the oceans or lakes. Such environment is characterized by rapid slope decrease and by loss of confinement of turbidity currents. It results in the deposition of Channel-Mouth-Lobes that can be separated from the channel mouth by an erosional (scoured) or by-pass dominated Channel-Lobe Transition Zone. Several factors can control the occurrence, extent and morphologic expression of the area such as the slope break angle, the upslope and downslope angle and the mud/sand ratio in flows. Disentangling these factors remains challenging due to the scarcity of outcrops and to the usual faint morphologies and low thickness of deposits. With bathymetric and seismic data we calculated the morphometric parameters of 8 channel-levees and their Channel-Mouth Lobes from the deepest area of the Rhone fan, a mud-sand rich system, and among which the youngest one (called neofan) was deposited at the end of the Last Glacial Maximum between 21.5 and 18.3 ka cal. BP. Emplacement and shape (finger-shaped or pear-shaped bulges) of Channel-Mouth Lobes is controlled by the seabed morphology (adjacent channel-levees and salt diapirs). A less prominent morphology of the neofan is attributed to premature quiescence related to the post sea-level rise sediment starvation. We show that the occurrence and expression of a Channel-Lobe Transition Zone is controlled by the gradient upstream of the channel mouth slope break. The extended Channel-Lobe Transition Zone and detached lobe of the neofan are attributed to the high upslope gradient (0.26°) while the less detached or attached lobes of other channel-levees is attributed to lower upslope gradient (0.13°). We show that scouring and scours concatenation into flutes at the Channel-Lobe Transition Zone is a major driver for the inception of channels and further confinement of turbidity current. For the first time we show that concatenation of scours in shingled disposition developed an incipient channel sinuosity at this very early stage of channel development. The channel-levee can extend downslope nearly instantaneously by tens of kilometers when isolated nascent channels connect to the channel mouth.
publishDate 2020
dc.date.none.fl_str_mv 2020
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
format article
status_str acceptedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/211140
url https://hdl.handle.net/2445/211140
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Versió postprint del document publicat a: https://doi.org/10.1016/j.geomorph.2020.107368
Geomorphology, 2020, vol. 369
https://doi.org/10.1016/j.geomorph.2020.107368
dc.rights.none.fl_str_mv (c) Elsevier B.V., 2020
info:eu-repo/semantics/openAccess
rights_invalid_str_mv (c) Elsevier B.V., 2020
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Elsevier B.V.
publisher.none.fl_str_mv Elsevier B.V.
dc.source.none.fl_str_mv Articles publicats en revistes (Dinàmica de la Terra i l'Oceà)
reponame:Dipòsit Digital de la UB
instname:Universidad de Barcelona
instname_str Universidad de Barcelona
reponame_str Dipòsit Digital de la UB
collection Dipòsit Digital de la UB
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15.301629

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