The depositional signature of cyclic steps: A late Quaternary analogue compared to modern active delta slopes
International audience Cyclic‐step bedforms typifying a Froude‐supercritical flow regime are a recurrent component of depositional/erosional turbiditic systems. Over modern delta slopes, cyclic steps have been inferred from observations of upslope‐migrating crescent‐shaped bedforms. However, the rec...
Published in: | Sedimentology |
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Main Authors: | , , , , , |
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Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2021
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Online Access: | https://insu.hal.science/insu-02960340 https://insu.hal.science/insu-02960340v3/document https://insu.hal.science/insu-02960340v3/file/Ghienne_Normandeau_EtAl_Sedimentology_CyclicSteps.pdf https://doi.org/10.1111/sed.12806 |
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Institut national des sciences de l'Univers: HAL-INSU |
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English |
topic |
Bedforms delta foreset Eastern Canada high‐density turbidites supercritical flows [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy |
spellingShingle |
Bedforms delta foreset Eastern Canada high‐density turbidites supercritical flows [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy Ghienne, Jean-François Normandeau, Alexandre Dietrich, Pierre Bouysson, Melanie Lajeunesse, Patrick Schuster, Mathieu The depositional signature of cyclic steps: A late Quaternary analogue compared to modern active delta slopes |
topic_facet |
Bedforms delta foreset Eastern Canada high‐density turbidites supercritical flows [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy |
description |
International audience Cyclic‐step bedforms typifying a Froude‐supercritical flow regime are a recurrent component of depositional/erosional turbiditic systems. Over modern delta slopes, cyclic steps have been inferred from observations of upslope‐migrating crescent‐shaped bedforms. However, the recognition in the sedimentary record of the resulting stratal pattern and depositional facies remains challenging. In this study, the depositional facies observed in exposed late Quaternary glaciofluvial upper delta‐slope sands (Portneuf‐Forestville, Québec) are compared to those cored from a modern analogue consisting of sediment waves interpreted as cyclic steps (Southwind Fjord, Baffin Island). The fossil and modern delta slopes share similar context, morphology and stratigraphic record. The clinoform foresets dip 2 to 6° and consist of prevailing sand‐sized material including subhorizontal to upslope‐dipping top‐cut‐out turbidites. Individually, the latter are 5 to 20 cm thick and massive to planar laminated (prevailing TA and TB subdivisions). In the fossil delta slope, related successions form relatively thick, well‐bedded suites, which are truncated downcurrent by, and onlap upstreamward on, inclined composite erosion surfaces here referred to as pseudo‐foresets. Pseudo‐foresets are regularly spaced (10 to 30 m) and have dips greater than the clinoform foresets (ca 20°). Large composite scours form pseudo‐channel structures filled in by structureless pebbly sand deformed by sheared flame structures, in association with coarse sand showing undulating lamination and rip‐up clasts. Similar depositional facies are observed on the modern delta slope. The stratal pattern is best compatible with upslope‐migrating bedforms and structureless sand indicates hydraulic jump deposits typical of cyclic steps. Cyclic‐step flow events, encompassing a succession of genetically linked erosional cyclic steps, depositional cyclic steps and subsequent waning‐flow conditions, were associated with the dense basal layer of ... |
author2 |
Institut de physique du globe de Strasbourg (IPGS) Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) Geological Survey of Canada Dartmouth (GSC Atlantic) Geological Survey of Canada - Office (GSC) Natural Resources Canada (NRCan)-Natural Resources Canada (NRCan) University of Johannesburg South Africa (UJ) Géosciences Rennes (GR) Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR) Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS) Université Laval Québec (ULaval) Department of Natural Resources, Government of Newfoundland and Labrador Canadian Network for Research and Innovation in Machining Technology, Natural Sciences and Engineering Research Council of Canada |
format |
Article in Journal/Newspaper |
author |
Ghienne, Jean-François Normandeau, Alexandre Dietrich, Pierre Bouysson, Melanie Lajeunesse, Patrick Schuster, Mathieu |
author_facet |
Ghienne, Jean-François Normandeau, Alexandre Dietrich, Pierre Bouysson, Melanie Lajeunesse, Patrick Schuster, Mathieu |
author_sort |
Ghienne, Jean-François |
title |
The depositional signature of cyclic steps: A late Quaternary analogue compared to modern active delta slopes |
title_short |
The depositional signature of cyclic steps: A late Quaternary analogue compared to modern active delta slopes |
title_full |
The depositional signature of cyclic steps: A late Quaternary analogue compared to modern active delta slopes |
title_fullStr |
The depositional signature of cyclic steps: A late Quaternary analogue compared to modern active delta slopes |
title_full_unstemmed |
The depositional signature of cyclic steps: A late Quaternary analogue compared to modern active delta slopes |
title_sort |
depositional signature of cyclic steps: a late quaternary analogue compared to modern active delta slopes |
publisher |
HAL CCSD |
publishDate |
2021 |
url |
https://insu.hal.science/insu-02960340 https://insu.hal.science/insu-02960340v3/document https://insu.hal.science/insu-02960340v3/file/Ghienne_Normandeau_EtAl_Sedimentology_CyclicSteps.pdf https://doi.org/10.1111/sed.12806 |
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ENVELOPE(-19.509,-19.509,65.690,65.690) |
geographic |
Baffin Island Canada Rip |
geographic_facet |
Baffin Island Canada Rip |
genre |
Baffin Island Baffin |
genre_facet |
Baffin Island Baffin |
op_source |
ISSN: 0037-0746 EISSN: 1365-3091 Sedimentology https://insu.hal.science/insu-02960340 Sedimentology, 2021, Supercritical ‐ flow processes and products, 68 (4), pp.1502-1538. ⟨10.1111/sed.12806⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1111/sed.12806 insu-02960340 https://insu.hal.science/insu-02960340 https://insu.hal.science/insu-02960340v3/document https://insu.hal.science/insu-02960340v3/file/Ghienne_Normandeau_EtAl_Sedimentology_CyclicSteps.pdf doi:10.1111/sed.12806 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1111/sed.12806 |
container_title |
Sedimentology |
container_volume |
68 |
container_issue |
4 |
container_start_page |
1502 |
op_container_end_page |
1538 |
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1790598223640920064 |
spelling |
ftinsu:oai:HAL:insu-02960340v3 2024-02-11T10:02:17+01:00 The depositional signature of cyclic steps: A late Quaternary analogue compared to modern active delta slopes Ghienne, Jean-François Normandeau, Alexandre Dietrich, Pierre Bouysson, Melanie Lajeunesse, Patrick Schuster, Mathieu Institut de physique du globe de Strasbourg (IPGS) Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) Geological Survey of Canada Dartmouth (GSC Atlantic) Geological Survey of Canada - Office (GSC) Natural Resources Canada (NRCan)-Natural Resources Canada (NRCan) University of Johannesburg South Africa (UJ) Géosciences Rennes (GR) Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR) Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS) Université Laval Québec (ULaval) Department of Natural Resources, Government of Newfoundland and Labrador Canadian Network for Research and Innovation in Machining Technology, Natural Sciences and Engineering Research Council of Canada 2021-06 https://insu.hal.science/insu-02960340 https://insu.hal.science/insu-02960340v3/document https://insu.hal.science/insu-02960340v3/file/Ghienne_Normandeau_EtAl_Sedimentology_CyclicSteps.pdf https://doi.org/10.1111/sed.12806 en eng HAL CCSD Blackwell Publishing info:eu-repo/semantics/altIdentifier/doi/10.1111/sed.12806 insu-02960340 https://insu.hal.science/insu-02960340 https://insu.hal.science/insu-02960340v3/document https://insu.hal.science/insu-02960340v3/file/Ghienne_Normandeau_EtAl_Sedimentology_CyclicSteps.pdf doi:10.1111/sed.12806 info:eu-repo/semantics/OpenAccess ISSN: 0037-0746 EISSN: 1365-3091 Sedimentology https://insu.hal.science/insu-02960340 Sedimentology, 2021, Supercritical ‐ flow processes and products, 68 (4), pp.1502-1538. ⟨10.1111/sed.12806⟩ Bedforms delta foreset Eastern Canada high‐density turbidites supercritical flows [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy info:eu-repo/semantics/article Journal articles 2021 ftinsu https://doi.org/10.1111/sed.12806 2024-01-24T17:31:31Z International audience Cyclic‐step bedforms typifying a Froude‐supercritical flow regime are a recurrent component of depositional/erosional turbiditic systems. Over modern delta slopes, cyclic steps have been inferred from observations of upslope‐migrating crescent‐shaped bedforms. However, the recognition in the sedimentary record of the resulting stratal pattern and depositional facies remains challenging. In this study, the depositional facies observed in exposed late Quaternary glaciofluvial upper delta‐slope sands (Portneuf‐Forestville, Québec) are compared to those cored from a modern analogue consisting of sediment waves interpreted as cyclic steps (Southwind Fjord, Baffin Island). The fossil and modern delta slopes share similar context, morphology and stratigraphic record. The clinoform foresets dip 2 to 6° and consist of prevailing sand‐sized material including subhorizontal to upslope‐dipping top‐cut‐out turbidites. Individually, the latter are 5 to 20 cm thick and massive to planar laminated (prevailing TA and TB subdivisions). In the fossil delta slope, related successions form relatively thick, well‐bedded suites, which are truncated downcurrent by, and onlap upstreamward on, inclined composite erosion surfaces here referred to as pseudo‐foresets. Pseudo‐foresets are regularly spaced (10 to 30 m) and have dips greater than the clinoform foresets (ca 20°). Large composite scours form pseudo‐channel structures filled in by structureless pebbly sand deformed by sheared flame structures, in association with coarse sand showing undulating lamination and rip‐up clasts. Similar depositional facies are observed on the modern delta slope. The stratal pattern is best compatible with upslope‐migrating bedforms and structureless sand indicates hydraulic jump deposits typical of cyclic steps. Cyclic‐step flow events, encompassing a succession of genetically linked erosional cyclic steps, depositional cyclic steps and subsequent waning‐flow conditions, were associated with the dense basal layer of ... Article in Journal/Newspaper Baffin Island Baffin Institut national des sciences de l'Univers: HAL-INSU Baffin Island Canada Rip ENVELOPE(-19.509,-19.509,65.690,65.690) Sedimentology 68 4 1502 1538 |