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Article ; Online: Sediment density flow distribution on wave‐influenced deltas

Normandeau, A. / Eamer, Jordan B. R. / Bernatchez, Pascal / Didier, David / Lajeunesse, Patrick / Limoges, A. / Montero‐Serrano, Jean‐Carlos

Sedimentology. 2023 Jan., v. 70, no. 1, p. 100-120

2023 , Page(s) 100–120

Abstract: Deltas are at the transition between fluvial and marine sedimentary environments where sediment density flows are often triggered during high river discharge events, forming submarine channels and sediment waves. On wave‐influenced deltas, longshore ... ...

Abstract	Deltas are at the transition between fluvial and marine sedimentary environments where sediment density flows are often triggered during high river discharge events, forming submarine channels and sediment waves. On wave‐influenced deltas, longshore currents are particularly efficient at transporting sediment alongshore, reducing the likelihood of sediment density flows from occurring at river mouths. This study describes four deltaic sedimentary systems at different stages of their evolution on a formerly glaciated continental inner shelf of eastern Canada in order to better understand the distribution of sediment density flows on wave‐influenced deltas. Three types of settings are recognized as being prone to sediment density flows: (i) in the early stages of wave‐influence and on large deltas, converging longshore currents can lead to offshelf sediment transport; (ii) on wave‐influenced to wave‐dominated deltas, a sandy spit can re‐route the river mouth and sediment density flows form where the spit intersects the delta lip; (iii) in advanced stages of wave‐dominated deltas and during their demise, rocky headlands are exposed and can intersect the slope, where off‐shelf sediment transport occurs. These types of sediment density flows were all characterized by debris flows or surge‐type turbidity currents which have limited offshore run‐out. More rarely, hyperpycnal flows form at the river mouths, especially where the river incises glaciomarine clays prone to landsliding in the river, which increases fine‐grained fluvial suspended sediment concentration. Overall, these results highlight the predominance of fluvial‐dominated deltas during a phase of relative sea‐level fall combined with high sediment supply. However, as soon as sediment supply diminishes, wave action remobilizes sediment alongshore modifying the distribution and types of sediment density flows occurring on wave‐influenced deltas.
Keywords	evolution ; river flow ; rivers ; sea level ; sediment transport ; sediments ; suspended sediment ; turbidity ; Canada
Language	English
Dates of publication	2023-01
Size	p. 100-120.
Publishing place	John Wiley & Sons, Ltd
Document type	Article ; Online
Note	JOURNAL ARTICLE
ZDB-ID	206889-8
ISSN	0037-0746
ISSN	0037-0746
DOI	10.1111/sed.13033
Database	NAL-Catalogue (AGRICOLA)

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Article: Retreat Pattern of Glaciers Controls the Occurrence of Turbidity Currents on High‐Latitude Fjord Deltas (Eastern Baffin Island)

Normandeau, A. / Dietrich, P. / Hughes Clarke, J. / Van Wychen, W. / Lajeunesse, P. / Burgess, D. / Ghienne, J.‐F.

Journal of geophysical research. 2019 June, v. 124, no. 6

2019

Abstract: Glacier and ice sheet mass loss as a result of climate change is driving important coastal changes in Arctic fjords. Yet limited information exists for Arctic coasts regarding the influence of glacial erosion and ice mass loss on the occurrence and ... ...

Abstract	Glacier and ice sheet mass loss as a result of climate change is driving important coastal changes in Arctic fjords. Yet limited information exists for Arctic coasts regarding the influence of glacial erosion and ice mass loss on the occurrence and character of turbidity currents in fjords, which themselves affect delta dynamics. Here we show how glacial erosion and the production of meltwaters and sediments associated with the melting of retreating glaciers control the generation of turbidity currents in fjords of eastern Baffin Island (Canada). The subaqueous parts of 31 river mouths along eastern Baffin Island were mapped by high‐resolution swath bathymetry in order to assess the presence or absence of sediment waves formed by turbidity currents on delta fronts. By extracting glaciological and hydrological watershed characteristics of these river mouths, we demonstrate that the presence and areal extent of glaciers are a key control for generating turbidity currents in fjords. However, lakes formed upstream during glacial retreat significantly alter the course of sediment routing to the deltas by forming temporary sinks, leading to the cessation of turbidity currents in the fjords. Due to the different deglaciation stages of watersheds in eastern Baffin Island, we put these results into a temporal framework of watershed deglaciation to demonstrate how the retreat pattern of glaciers, through the formation and filling of proglacial lakes, affects the turbidity current activity of deltas.
Keywords	climate change ; geophysics ; glaciation ; glaciers ; hydrology ; ice ; latitude ; research ; sediments ; turbidity ; watersheds ; Arctic region ; Canada
Language	English
Dates of publication	2019-06
Size	p. 1559-1571.
Publishing place	John Wiley & Sons, Ltd
Document type	Article
Note	JOURNAL ARTICLE
ISSN	2169-9003
DOI	10.1029/2018JF004970
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: Late glacial retreat of the Lancaster Sound Ice Stream and early Holocene onset of Arctic/Atlantic throughflow in the Arctic Island channels

Kelleher, Robert / Jennings, Anne / Andrews, John / Brooks, Nicole K. S. / Marchitto, Tom / Feng, Shaoting / Woelders, Lineke / Normandeau, A. / Jenner, Kimberley / Bennett, R. / Brookins, Sarah

Arctic, Antarctic, and Alpine Research. 2022 Dec. 31, v. 54, no. 1 p.395-427

2022

Abstract: Multiple proxies in three sediment cores from Northwestern Baffin Bay document the timing of Lancaster Sound Ice Stream (LSIS) retreat that led to Arctic–Atlantic throughflow in Parry Channel, an important source of freshwater that can impact the ... ...

Abstract	Multiple proxies in three sediment cores from Northwestern Baffin Bay document the timing of Lancaster Sound Ice Stream (LSIS) retreat that led to Arctic–Atlantic throughflow in Parry Channel, an important source of freshwater that can impact the Atlantic Meridional Overturning Circulation. The Late Glacial to Holocene timing of ice retreat and channel opening and the responses of the regional ocean environment to these events are presented. We use quantitative mineral composition, foraminiferal assemblages, biogenic silica, ice-rafted debris (IRD), and ¹⁴C-based age models to document and date the events and environmental changes occurring during deglaciation of this major marine channel. Findings show that retreat of the LSIS into Lancaster Sound occurred before ~15.3 cal ka BP, about 800 years before the onset of major iceberg calving events from the LSIS, named the Baffin Bay Detrital Carbonate events (BBDC 1 and BBDC 0). The end of BBDC 0 occurred at ~10.6 cal ka BP, which coincides with the opening of Parry Channel. A marine environment productive of calcareous benthic and planktic foraminifera, with diminished meltwater, seasonal sea ice, warmer summer temperatures, and inflowing, nutrient-rich Arctic surface water characterizes the interval between the opening of Parry Channel and the opening of Nares Strait. Paired planktic and benthic ¹⁴C ages over this 2,200-year interval show diminishing age offsets suggesting progressive mixing of the upper ~850–900 m of the water column. The opening of Nares Strait by ~8.2 cal ka BP coincides with increased biogenic silica in the form of abundant, large centric diatoms and dissolution of CaCO₃. The paucity of calcareous organisms after 8.2 cal ka BP resulted in poor chronological control in the cores to interpret changing environments after 8.2 cal ka BP.
Keywords	Holocene epoch ; Retaria ; carbonates ; freshwater ; glaciation ; marine environment ; mineral content ; research ; sea ice ; sediments ; silica ; snowmelt ; streams ; summer ; surface water ; Antarctic region ; Arctic region ; Deglaciation ; Parry Channel ; BBDC events ; Baffin Bay ; foraminifera
Language	English
Dates of publication	2022-1231
Size	p. 395-427.
Publishing place	Taylor & Francis
Document type	Article ; Online
ZDB-ID	2045941-5
ISSN	1938-4246 ; 1523-0430
ISSN (online)	1938-4246
ISSN	1523-0430
DOI	10.1080/15230430.2022.2110689
Database	NAL-Catalogue (AGRICOLA)

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Book ; Online: Influence of a small submarine canyon on biogenic matter export flux in the Lower St. Lawrence Estuary, eastern Canada

Sharpe, Hannah / Gosselin, Michel / Lalande, Catherine / Normandeau, Alexandre / Montero-Serrano, Jean-Carlos / Baccara, Khouloud / Bourgault, Daniel / Sherwood, Owen / Limoges, Audrey

eISSN:

2023

Abstract: Submarine canyons enhance shelf-slope sediment exchange and influence hydrodynamic processes, with consequences for biogeochemical cycles. This work documents variations in the vertical export of biogenic matter on the northern shore of the Lower St. ... ...

Abstract	Submarine canyons enhance shelf-slope sediment exchange and influence hydrodynamic processes, with consequences for biogeochemical cycles. This work documents variations in the vertical export of biogenic matter on the northern shore of the Lower St. Lawrence Estuary (LSLE, Quebec, eastern Canada), which is characterized by the presence of an active submarine canyon system. A total of three moorings were deployed from November 2020 to September 2021. One nearshore mooring was deployed in the main axis of the Pointe-des-Monts (PDM) canyon system and was equipped with an Acoustic Doppler Current Profiler (ADCP), and two moorings equipped with sediment traps were deployed in the distal PDM canyon system and offshore Baie-Comeau (BC). The ADCP data revealed the occurrence of a minor sediment remobilization event (December 2020) and a small turbidity current (February 2021) in the canyon. Concurrent elevated fluxes of total particulate matter, particulate organic carbon, particulate nitrogen, and chloropigments showed that these events left a signature in the distal PDM sediment trap located >2.6 km further offshore. The composition of diatom and dinoflagellate assemblages was similar in the canyon system and offshore BC, but the diatom bloom occurred two weeks earlier (in mid-April) at the PDM site, where annual diatom and dinoflagellate fluxes were almost 2 times lower than at the BC site. A bloom of the potentially toxic diatom Pseudo-nitzschia seriata was also observed during the second half of September 2021 at the BC site. This study notably helps identify the relationship between near-bed canyon processes and biogenic matter export in the water column, thereby directly influencing the regional ecosystem. The study period further covered an anomalously nearly ice-free winter and thus, in the context of climate change, provides valuable insight into future trends of biogenic matter export in the LSLE.
Subject code	550 ; 551
Language	English
Publishing date	2023-07-17
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Climate and permafrost effects on the chemistry and ecosystems of High Arctic Lakes.

Roberts, K E / Lamoureux, S F / Kyser, T K / Muir, D C G / Lafrenière, M J / Iqaluk, D / Pieńkowski, A J / Normandeau, A

Scientific reports

2017 Volume 7, Issue 1, Page(s) 13292

Abstract: Permafrost exerts an important control over hydrological processes in Arctic landscapes and lakes. Recent warming and summer precipitation has the potential to alter water availability and quality in this environment through thermal perturbation of near ... ...

Abstract	Permafrost exerts an important control over hydrological processes in Arctic landscapes and lakes. Recent warming and summer precipitation has the potential to alter water availability and quality in this environment through thermal perturbation of near surface permafrost and increased mobility of previously frozen solutes to Arctic freshwaters. We present a unique thirteen-year record (2003-16) of the physiochemical properties of two High Arctic lakes and show that the concentration of major ions, especially SO
Language	English
Publishing date	2017-10-16
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2615211-3
ISSN	2045-2322 ; 2045-2322
ISSN (online)	2045-2322
ISSN	2045-2322
DOI	10.1038/s41598-017-13658-9
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Active faulting controls bedform development on a deep-water fan

Maselli, Vittorio / Micallef, Aaron / Normandeau, Alexandre / Oppo, Davide / Iacopini, David / Green, Andrew / Ge, Zhiyuan

2021

Abstract: Tectonically controlled topography influences deep-water sedimentary systems. Using 3-D seismic reflection data from the Levant Basin, eastern Mediterranean Sea, we investigate the spatial and temporal evolution of bedforms on a deep-water fan cut by an ... ...

Abstract	Tectonically controlled topography influences deep-water sedimentary systems. Using 3-D seismic reflection data from the Levant Basin, eastern Mediterranean Sea, we investigate the spatial and temporal evolution of bedforms on a deep-water fan cut by an active normal fault. In the footwall, the fan comprises cyclic steps and antidunes along its axial and external portions, respectively, which we interpret to result from the spatial variation in flow velocity due to the loss of confinement at the canyon mouth. Conversely, in the hanging wall, the seafloor is nearly featureless at seismic scale. Numerical modeling of turbidity currents shows that the fault triggers a hydraulic jump that suppresses the flow velocity downstream, which thus explains the lack of visible bedforms basinward. This study shows that the topography generated by active normal faulting controls the downslope evolution of turbidity currents and the associated bedforms and that seafloor geomorphology can be used to evince syn-tectonic deposition.
Subject code	550
Language	English
Publishing date	2021-08-30
Publisher	GSA (Geological Society of America)
Publishing country	de
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Reconstructing ice-margin retreat using delta morphostratigraphy.

Dietrich, Pierre / Ghienne, Jean-François / Normandeau, Alexandre / Lajeunesse, Patrick

Scientific reports

2017 Volume 7, Issue 1, Page(s) 16936

Abstract: The paleogeographic reconstruction of the successive inland positions of a retreating ice sheet is generally constrained by mapping moraines. However, deltaic complexes constructed by sediment-charged meltwater can also provide a record of the retreating ...

Abstract	The paleogeographic reconstruction of the successive inland positions of a retreating ice sheet is generally constrained by mapping moraines. However, deltaic complexes constructed by sediment-charged meltwater can also provide a record of the retreating ice-margin positions. Here, we examine a serie of ice-contact, ice-distal glaciofluvial and paraglacial depositional systems that developed along the Québec North Shore (eastern Canada) in the context of falling relative sea level during the northward retreat of the Laurentide Ice Sheet (LIS). Ice-contact depositional systems formed when the LIS was stillstanding along the Québec North Shore. Subsequent inland retreat of the ice margin generated glacial meltwaters feeding sediment to glaciofluvial deltas, leading to their rapid progradation. The retreat of the ice margin from drainage basins was marked by the onset of paraglacial processes such as the shutdown of delta progradation, severe fluvial entrenchment, and deposition of shallow-marine strata. Four end-member scenarios describe the spatial and stratigraphic distribution of these three depositional systems (ice-contact deposits, ice-distal glaciofluvial deltas, and paraglacial suites). They reflect both the inherited drainage basin physiography and the retreat pattern of the ice margin. Applied to twenty deltaic complexes, these end-members allowed us to refine the model of LIS-margin retreat over southeastern Québec.
Language	English
Publishing date	2017-12-05
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2615211-3
ISSN	2045-2322 ; 2045-2322
ISSN (online)	2045-2322
ISSN	2045-2322
DOI	10.1038/s41598-017-16763-x
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Author Correction: Northwestern Pacific tropical cyclone activity enhanced by increased Asian dust emissions during the Little Ice Age.

Yang, Yang / Piper, David J W / Xu, Min / Gao, Jianhua / Jia, Jianjun / Normandeau, Alexandre / Chu, Dongdong / Zhou, Liang / Wang, Ya Ping / Gao, Shu

Nature communications

2022 Volume 13, Issue 1, Page(s) 2596

Language	English
Publishing date	2022-05-05
Publishing country	England
Document type	Published Erratum
ZDB-ID	2553671-0
ISSN	2041-1723 ; 2041-1723
ISSN (online)	2041-1723
ISSN	2041-1723
DOI	10.1038/s41467-022-30171-4
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Northwestern Pacific tropical cyclone activity enhanced by increased Asian dust emissions during the Little Ice Age.

Yang, Yang / Piper, David J W / Xu, Min / Gao, Jianhua / Jia, Jianjun / Normandeau, Alexandre / Chu, Dongdong / Zhou, Liang / Wang, Ya Ping / Gao, Shu

Nature communications

2022 Volume 13, Issue 1, Page(s) 1712

Abstract: Instrumental records reveal that intense tropical cyclone (TC) activity varies with tropical sea surface temperature (SST) on annual-decadal scales. Drivers of intense TC activity at the centennial-millennial scale are less clear, due to the sparseness ... ...

Abstract	Instrumental records reveal that intense tropical cyclone (TC) activity varies with tropical sea surface temperature (SST) on annual-decadal scales. Drivers of intense TC activity at the centennial-millennial scale are less clear, due to the sparseness of pre-observational reconstructions. Here, we present a new 2 kyr continuous activity record of intense TCs from offshore eastern China. Our reconstruction indicates that this site witnessed enhanced TC activity during relatively warm periods, with a widespread increase in TC activity during the later part of the Little Ice Age. This latter observation reveals that enhanced TC activity was synchronized with increased Asian dust emissions during the Little Ice Age. TC activity was also lower in the late Roman Warm Period, when SST was higher but Asian dust emissions were lower than in the early phase. Such patterns suggest a centennial-millennial link between TC climatology and a combination of SST changes and Asian dust levels.
MeSH term(s)	China ; Cyclonic Storms ; Dust ; Temperature
Chemical Substances	Dust
Language	English
Publishing date	2022-03-31
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2553671-0
ISSN	2041-1723 ; 2041-1723
ISSN (online)	2041-1723
ISSN	2041-1723
DOI	10.1038/s41467-022-29386-2
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article: Submarine canyons and channels in the Lower St. Lawrence Estuary (Eastern Canada): Morphology, classification and recent sediment dynamics

Normandeau, Alexandre / Guillaume St-Onge / Patrick Lajeunesse

Geomorphology. 2015 July 15, v. 241

2015

Abstract: Series of submarine canyons and channels observed in the Lower St. Lawrence Estuary (LSLE) provide an opportunity to analyze in great detail the morphology, spatial distribution and modern activity of such systems in a relatively shallow (≤300m) semi- ... ...

Abstract	Series of submarine canyons and channels observed in the Lower St. Lawrence Estuary (LSLE) provide an opportunity to analyze in great detail the morphology, spatial distribution and modern activity of such systems in a relatively shallow (≤300m) semi-enclosed basin. Based on their geomorphology and physical settings, the canyons and channels were classified into four categories according to their feeding sources (ancient or recent): glacially-fed, river-fed, longshore drift-fed and sediment-starved systems. Their activity was interpreted based on geomorphological characteristics such as the presence of bedforms related to gravity flows, backscatter intensity, axial incision and the presence of rapidly deposited layers in surficial sediments. River-fed deltas were interpreted as inactive, mainly because suspended sediment concentrations at river mouths are low, preventing the generation of hyperpycnal currents or delta-lip failures related to high sediment supply. Longshore drift-fed canyons, present where the coastal shelf narrows, were found to be episodically active probably due to earthquakes or extreme storm events. Unlike other longshore drift-fed canyons observed elsewhere in the world, they are active infrequently because of the modern low rates of sediment supply to their heads. The most active canyons are the sediment-starved type and were observed near Pointe-des-Monts. Their activity is probably due to slope failures and to the presence of strong hydrodynamic processes. Therefore, sediment supply is not the main mechanism responsible for modern canyon and channel activity in the LSLE. However, sediment supply has been an important factor during the formation of the submarine channels and canyons. Their quasi-exclusive occurrence on the Québec North Shore is attributed to its larger watershed and important sedimentary delivery during deglaciation. The Québec North Shore watershed is 20 times greater than the Québec South Shore watershed, which favored the transport of greater volumes of sediment during the early-Holocene. Moreover, the slope proximity to the shore led to the formation of longshore-drift fed systems on the North Shore when sediment supplied to rivers were transferred on a narrow shelf.
Keywords	basins ; canyons ; earthquakes ; estuaries ; glaciation ; gravity ; hydrodynamics ; rivers ; sediments ; storms ; suspended sediment ; watersheds ; Quebec
Language	English
Dates of publication	2015-0715
Size	p. 1-18.
Publishing place	Elsevier B.V.
Document type	Article
ZDB-ID	58028-4
ISSN	0169-555X
ISSN	0169-555X
DOI	10.1016/j.geomorph.2015.03.023
Database	NAL-Catalogue (AGRICOLA)

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