Guillaume St-Onge

Guillaume St-Onge
Université du Québec à Rimouski UQAR | uqar · Institut des Sciences de la Mer de Rimouski (ISMER)

PhD

About

221
Publications
41,853
Reads
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3,908
Citations
Citations since 2017
66 Research Items
2149 Citations
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Introduction
Prof. Guillaume St-Onge holds the Tier I Canada Research Chair in Marine Geology. He has developed state-of-the-art infrastructures in marine geology, sedimentology and paleomagnetism. His main research activities are: 1) Marine geology and sedimentology, 2) Quaternary stratigraphy and paleoceanography, 3) Natural hazards and 4) Paleomagnetism. His work focuses on high latitudes of both hemispheres, and he has an extensive experience at sea and as a chief scientist.
Additional affiliations
January 2020 - present
Institut des sciences de la mer de Rimouski (ISMER)
Position
  • Managing Director
October 2016 - December 2019
Institut France-Québec Maritime/France-Quebec Maritime Institute
Position
  • Managing Director
June 2016 - December 2019
Réseau Québec maritime/Québec Maritime Network
Position
  • Managing Director

Publications

Publications (221)
Article
Along with the dramatic decrease in global geomagnetic field intensity, recent observations demonstrate that the geomagnetic field in the Arctic has dramatically changed over the last century. This change is best illustrated by the recent migration of the North Magnetic Pole (which has been in the Canadian Arctic for the last 400 years) into the Ar...
Article
Full-text available
The Pingualuit Crater (Ungava Peninsula, Canada) hosts a freshwater basin in which a subglacial lake subsisted under the Laurentide Ice Sheet during the last glacial period. Microfacies and microstructures of a 9 m-long sediment core are presented to discuss the depositional environment of deformed glacigenic and postglacial sequences deposited in...
Article
We use pollen and dinocyst assemblages from three sedimentary sequences of the San Jorge Gulf (SJG) to document the vegetation history of the extra-Andean/eastern Patagonia (Argentina), and the latitudinal variations of the Southern Westerly Wind Belt (SWWB) in relation with ocean changes during the Late Pleistocene and Holocene. Our results sugges...
Article
Full-text available
Rapidly deposited layers (RDL) such as turbidites or hyperpycnites are mostly studied for their sedimentological properties, but are carefully avoided in paleomagnetic studies due to the disturbances caused by such sudden and rapid sediment accumulation. Therefore, these layers can also be seen as potential indicators of sediment parameters suscept...
Article
In eastern Canada, the Charlevoix-Kamouraska/Bas-Saint-Laurent (CKBSL) seismic zone presents a seismic hazard almost as high as that of the active Pacific zone. The major event of February 5, 1663 CE, with an estimated magnitude of ≥7, highlights the importance of this seismic hazard. The numerous submarine landslides mapped in the St. Lawrence Est...
Conference Paper
Full-text available
We release images of the submarine bottom from the northern sector of the Golfo San Jorge, within the Southern Patagonia Coastal Marine Interjurisdictional Park (PIMCPA for its initials in Spanish). The images were obtained through a high-resolution multi-beam echo sounder Kongsberg Maritime EM 2040 during the 2014 oceanographic campaign of the R/V...
Article
Full-text available
This paper presents a new annually laminated record (varves) from Lake Walker, Québec North Shore (eastern Canada) spanning the period from ~ 3230 to 2320 ± 20 cal BP. A ~ 3.5-m-long composite sequence was established with the best regular and continuous laminated intervals using computed tomography and high-resolution photographs. The varve chrono...
Article
Full-text available
The physical, sedimentological, mineralogical and elemental geochemical properties of sediment cores AMD1803-02BC and 01PC from the Cape Norton Shaw Inlet were investigated to reconstruct glacial sediment discharges from southeastern Manson Icefield and document the impact of ice–ocean interactions on the sediment dynamics and opening of the North...
Article
International Ocean Drilling Program (IODP) Expedition 341 recovered sediments from the south Alaska continental slope that preserves a well resolved and dated inclination record over most of the past ∼43,000 years. The Site U1419 chronology (Walczak et al., 2020) is among the highest resolution in the world, constrained by 173 radiocarbon dates, p...
Article
The Arctic has warmed significantly over the past decades. However, the evolution of Arctic climate during the Holocene remains to be clarified in more detail, and regional factors controlling aquatic ecosystem evolution need to be better defined to grasp the sensitivity of lakes to rapid environmental change. Nettilling Lake was studied for change...
Article
Paleomagnetism is a powerful tool for establishing an almost continuous chronostratigraphy for an entire region. When combined with other dating methods, absolute or relative, it can be used to develop a regional reference chronostratigraphic framework. During the summer of 2016, several piston cores were collected along the Atlantic side of the Le...
Article
Full-text available
Global warming due to anthropogenic factors can be amplified or dampened by natural climate oscillations, especially those involving sea surface temperatures (SSTs) in the North Atlantic which vary on a multidecadal scale (Atlantic multidecadal variability, AMV). Because the instrumental record of AMV is short, long-term behavior of AMV is unknown,...
Article
This paper analyzes the distribution patterns of pollen and spore assemblages in modern surface sediments recovered from the bottom of the San Jorge Gulf (SJG) and from offshore sites, in relation to the location of different phytogeographic provinces surrounding the SJG, including the distant forest from southwestern Patagonia. Results reveal that...
Article
Full-text available
The mineralogical and geochemical compositions of three sediment cores from the northwestern Greenland continental margin (AMD14‐204, AMD14‐210) and Kane Basin (AMD14‐Kane2B) were investigated using quantitative X-ray diffraction (qXRD) and X-ray fluorescence (ED-XRF) in order to document the impact of ice-ocean interactions on the sediment provena...
Chapter
The landscape and landforms of the Magdalen Islands are uniquely varied for such a small archipelago. Geomorphologically they are a part of the Maritime Plain which is located near the center of the Maritime Basin (375–325 Ma). The Magdalen Islands were pushed to the surface by salt-diapirs (~300 Ma). Formed by volcanic hills (basalt) surrounded by...
Article
Three sediment cores recovered on the lower slope of the continental shelf in western Baffin Bay (Arctic Canada) as well as swath bathymetry and subbottom profiler data collected on the shelf and slope of the region were analysed to investigate whether the Laurentide Ice Sheet (LIS) reached the shelf edge offshore Home Bay during the Last Glacial M...
Article
Full-text available
Three sediment cores recovered on the lower slope of the continental shelf in western Baffin Bay (Arctic Canada) as well as swath bathymetry and subbottom profiler data collected on the shelf and slope of the region were analysed to investigate whether the Laurentide Ice Sheet (LIS) reached the shelf edge offshore Home Bay during the Last Glacial M...
Article
The monitoring of turbidity currents enables accurate internal structure and timing of these flows to be understood. Without monitoring, triggers of turbidity currents often remain hypothetical and are inferred from sedimentary structures of deposits and their age. In this study, the bottom currents within 20 m of the seabed in one of the Pointe‐de...
Article
Few annually laminated (varved) lacustrine records exist in the Arctic, but these high-resolution climate archives are needed to better understand abrupt climate change and the natural mode of climate variability of this sensitive region. This paper presents a new high-resolution 2900-year long varved lake sediment record from the Fosheim Peninsula...
Conference Paper
Full-text available
Sedimentary diatoms have been successfully used to quantitatively reconstruct diverse limnological variables, including temperature, at various timescales. Even though temperature is often less of a key driver of diatom ecology than other environmental parameters (such as water chemistry), inference models based on diatom assemblage composition hav...
Article
Between 22 and 17 cal ka BP, five large meltwater events from within the Laurentian Channel Ice Stream deposited mud beds meters thick across a large area of the Laurentian Fan and adjacent continental slopes. This study determines the sources of these event beds and relates them to the glaciological evolution of the retreating Laurentian Ice Strea...
Article
Full-text available
The rare earth element (REE) concentrations and radiogenic isotope (Sr-Nd-Hf) compositions measured in bulk sediment leachates, together with bulk and clay mineralogical data, from two piston cores recovered in the Canadian Beaufort (AMD0214-02PC) and Chukchi-Alaskan (HLY0501-01JPC) margins were studied to investigate changes in the weathering regi...
Article
Full-text available
A radiocarbon-dated marine sediment core retrieved in Kane Basin, central Nares Strait, was analysed to constrain the timing of the postglacial opening of this Arctic gateway and its Holocene evolution. This study is based on a set of sedimentological and geochemical proxies of changing sedimentary processes and sources that provide new insight int...
Article
Full-text available
The presence of upwelling systems and oceanic fronts makes the Southwest Atlantic Ocean a region of high primary productivity. These same conditions are present in San Jorge Gulf (SJG) along the southern Argentinian coast, where dinoflagellates and diatoms dominate primary production. The distribution of these microorganisms, including the cysts pr...
Article
Full-text available
Sampling of sediment cores using plastic U-channels has made possible the acquisition of detailed records of paleomagnetic secular variation, geomagnetic polarity, environmental magnetic studies, and relative paleointensity over the past several million years. U-channel measurements provide the great advantage of rapid measurements of long sediment...
Article
The northeastern Baffin Bay continental margin, which experiences high sediment accumulation rates, is an excellent location to study Holocene sedimentary variations. However, it is often difficult to obtain reliable chronologies of the sediment archives using traditional methods (δ¹⁸O and radiocarbon) due to specific oceanographic conditions (e.g....
Article
Full-text available
The Gulf of San Jorge (GSJ) is a semicircular basin, approximately 160 km long and 250 km wide, located in the central part of Patagonia between 45°S and 47°S, lacking any present-day major perennial tributaries. The grain size and bulk and clay mineralogical compositions as well as major and minor elements of 75 surface sediment samples from the G...
Conference Paper
Full-text available
Paleomagnetic studies have mostly focused on hemipelagic sediments, avoiding all rapidly deposited layers such as turbidites to reconstruct Earth' geomagnetic field variations. Nonetheless, a few laboratory experiments and natural sediment core studies have begun to explore the impact of such rapidly deposited layers on the paleomagnetic records in...
Article
Full-text available
A radiocarbon dated marine sediment core retrieved in Kane Basin, central Nares Strait, was analysed to constrain the timing of the postglacial opening of this Arctic gateway and its Holocene evolution. This study is based on a set of sedimentological and geochemical proxies of changing sedimentary processes and sources that translate into ice shee...
Article
Full-text available
Marine sediments preserve archives of glacier behavior from many proxies, with lithofacies analysis providing direct evidence of glacial extent and dynamics. Many of these lithofacies have corresponding physical and geochemical properties that may be identified through quantitative, nondestructive logging properties. This study applies supervised a...
Article
Full-text available
Two sediment piston cores were recovered from the Chukchi-Alaskan (05JPC) and Canadian Beaufort (02PC) margins to investigate grain-size, geochemical and mineralogical compositions. This allowed the reconstruction of changes in detrital sediment provenance and transport related to climate variability since the last deglaciation. The end-member mode...
Article
Full-text available
Ancient harbours are rich archives of human-environment interaction. However, dating harbour deposits and correlating their stratigraphy is a major challenge because of typically high sedimentation rates over short periods and possible curative dredging events. Portus, the maritime harbour of Rome at the height of the Roman Empire, was a port compl...
Article
Eastern Canadian margin sediments bear testimony to several catastrophic deglacial meltwater discharges from the retreating Laurentide Ice Sheet. The reddish-brown plumite layers deposited on the levees of the Laurentian Fan valleys have been recognized as indications of multiple outburst floods between Heinrich events 2 and 1. Five event layers ha...
Article
Full-text available
This paper analyzes short gravity cores sampled along transects in three adjacent deep fjord-lakes (lakes Pentecôte, Walker, and Pasteur) on the Québec North Shore, eastern Canada, to evaluate the distribution of laminated sediments and potential for varve formation. Facies analysis based on lithological description, digital photos, CT-scan images,...
Presentation
Sedimentary diatoms have been used to quantitatively reconstruct diverse limnological variables, including temperature. Even though the temperature is often less of a key driver of diatom ecology than other environmental parameters, inference models based on diatom assemblage composition have been shown to be reliable proxies for water temperature....
Poster
Full-text available
These expanded records allow paleomagnetic secular variation (PSV) from the Baffin Bay to be studied in high-resolution and will thus make it possible to reconstitute the variations of the magnetic field in order to establish a chronostratigraphy of the sedimentary sequences and to deduce the advances and glacial retreats.
Article
Full-text available
Palaeomagnetic investigation of three sediment cores from the Chukchi and Beaufort Sea margins was performed to better constrain the regional chronostratigraphy and to gain insights into sediment magnetic properties at the North American Arctic margin during the Holocene and the preceding deglaciation. Palaeomagnetic analyses reveal that the sedime...
Article
The goals of this work were to study sedimentary organic matter (OM) composition and transformation since the end of the last deglaciation and to evaluate the influence of contrasting depositional conditions on these parameters. One station was located in the Lower St. Lawrence Estuary (LSLE) where the current bottom waters are hypoxic and receive...
Article
RESUMEN El Margen Continental Patagónico (MCP) es, desde un punto de vista geológico, la porción del Margen Continental Argentino Pasivo Volcánico (MCAPV) ubicada al sur de la Zona de la Fractura Colorado. Esta zona del margen se encuentra influenciada desde el límite Eoceno-Oligoceno, por la circulación termohalina de las corrientes de agua profun...
Article
Three radiocarbon dated sediment cores from trough mouth fans on the central west Greenland continental slope were studied to determine the timing and processes of Greenland Ice Sheet (GIS) retreat from the shelf edge during the last deglaciation and to test the role of ocean forcing (i.e. warm ocean water) thereon. Analyses of lithofacies, quantit...
Article
The Magdalen Islands (Québec, Canada) in the centre of the Gulf of St. Lawrence are located in a strategic position for providing an overview of the relative sea-level (RSL) history of the Maritime Provinces of eastern Canada. Although data are available for the coastal terrestrial areas of the Maritimes, data from the Gulf are very scarce and both...
Research
Full-text available
Rapport annuel d'activités 2016-2017 du Réseau Québec maritime (RQM) 2016-2017 Annual report of the Québec Maritime Network (RQM)
Article
The evolution of deltas and submarine fans is often envisioned as largely controlled by relative sea-level variations. However, in some cases, relative sea level can have less effect on delta and submarine fan activity than sediment supply and shelf geomorphology. In order to document the relative importance of these three factors on deltaic and su...
Article
Full-text available
The Argentine margin contains important sedimentological, paleontological and chemical records of regional and local tectonic evolution, sea level, climate evolution and ocean circulation since the opening of the South Atlantic in the Late Jurassic–Early Cretaceous as well as the present-day results of post-depositional chemical and biological alte...
Poster
Full-text available
These results and paleomagnetic data indicate that the chronostratigraphy is similar both inside and outside the crater and that sediments possibly deposited before the last glaciation could not be sampled.
Article
Full-text available
Mineralogical, geochemical, magnetic, and siliciclastic grain-size signatures of 34 surface sediment samples from the Mackenzie-Beaufort Sea Slope and Amundsen Gulf were studied in order to better constrain the redox status, detrital particle provenance, and sediment dynamics in the western Canadian Arctic. Redox-sensitive elements (Mn, Fe, V, Cr,...
Article
Full-text available
Physical properties, grain size, bulk mineralogy, elemental geochemistry and magnetic parameters of three sediment piston cores recovered in the Laurentian Channel from its head to its mouth were investigated to reconstruct changes in detrital sediment provenance and transport related to climate variability since the last deglaciation. The comparis...
Poster
The Argentine Continental Shelf (ACS) extends along a relatively stable continental margin at the intersection of the present Antarctic ice sheet and the relic of the former Patagonian ice sheet. This provides a preferential area to study the Quaternary sea-level fluctuations and to analyse the impact of ice extent variations on sedimentary process...