Late-Quaternary morphostratigraphy of Lake St-Joseph (southeastern Canadian Shield): Evolution from a semi-enclosed glacimarine basin to a postglacial lake

Normandeau, Alexandre; Lajeunesse, Patrick; Philibert, G

doi:10.1016/j.sedgeo.2013.07.005

Cited by 31 publications

(56 citation statements)

References 87 publications

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“…1 and 8). Similar bedrock profi les have also been observed in seismic data at the bottom of Lake Jacques-Cartier, fjord-like Lake Mékinac, and Lake St. Joseph (Normandeau et al, 2013;Fig. 1).…”

Section: Glacigenic Versus Fluvial Originsupporting

confidence: 72%

Buried preglacial fluvial gorges and valleys preserved through Quaternary glaciations beneath the eastern Laurentide Ice Sheet

Lajeunesse¹

2014

Geological Society of America Bulletin

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The geomorphology, geometry, and sedimentary infi ll of buried gorges and V-shaped valleys observed at the base of major river valleys in the formerly glaciated southeastern Canadian Shield region have been revealed from excavation and drilling data acquired during the construction of hydroelectric dams and seismic data collected on lakes and offshore. Compilation of these previously published and unpublished data provided an exceptional opportunity to examine the morphology and spatial distribution of buried bedrock gorges and the mechanical processes responsible for their erosion. In some valleys, detailed observations of deep gorges have been allowed by their exhumation over large areas. Archive photographs show deep and large potholes, natural pillars, furrows, fl utes, and scallops on the wellpolished bedrock walls of the gorges. They also reveal that gorges and valleys have a sharp-ending V shape and very narrow base and are superimposed by a U-shaped valley, forming a buried valley-within-valley topography. The narrow and deep cross-profi le of these gorges, their well-polished slopes, and the type of bedforms observed within them are typical features of fl uvial bedrock channels. Drilling operations at many sites have also provided data on bedrock topography of these gorges within valleys and on the nature of their sedimentary infi ll. The different lines of evidence presented in this paper indicate that gorges and V-shaped valleys of the region were not eroded by the Laurentide Ice Sheet during Quaternary glaciations but are relics of a preserved preglacial fl uvial system eroded during a lower base level. This paleofl uvial system is interpreted to be linked to fl uvially cut channels observed on the seafl oor of the Estuary and Gulf of St. Lawrence.

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Section: Glacigenic Versus Fluvial Originsupporting

confidence: 72%

Buried preglacial fluvial gorges and valleys preserved through Quaternary glaciations beneath the eastern Laurentide Ice Sheet

Lajeunesse¹

2014

Geological Society of America Bulletin

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“…High‐resolution Chirp subbottom profilers were previously used in High Arctic environments [ Gilbert and Desloges , ; Lamoureux et al ., ], while swath bathymetry has never been carried out because of the difficulty of transporting complex instrumentation to these remote and isolated locations and deploying them from small inflatable boats. However, swath bathymetry, in combination with high‐resolution Chirp subbottom profilers, can provide a very detailed framework of the geological settings and processes acting on sediment distribution [ Hilbe and Anselmetti , ; Normandeau et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Sediment dynamics in paired High Arctic lakes revealed from high‐resolution swath bathymetry and acoustic stratigraphy surveys

et al. 2016

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High Arctic lakes are commonly used for paleoclimatic reconstructions because they are particularly sensitive to climate variability. However, the processes leading to sediment deposition and distribution in these lakes are often poorly understood. Here for the first time in the Canadian High Arctic, we present original data resulting from swath bathymetry and subbottom surveys carried out on two lakes at Cape Bounty, Melville Island. The results reveal the dynamic nature of the lakes, in which mass movement deposits and bedforms on the deltas reflect frequent slope instabilities and hyperpycnal flow activity. The analysis of the mass movement deposits reveals that small blocky debris flows/avalanches, debris flows, and a slide occurred during the Holocene. These mass movements are believed to have been triggered by earthquakes and potentially by permafrost thawing along the shoreline. Altogether, these mass movement deposits cover more than 30% of the lake floors. Additionally, the river deltas on both lakes were mapped and reveal the presence of several gullies and bedforms. The presence of gullies along the delta front indicates that hyperpycnal flows generated at the river mouth can transport sediment in different trajectories downslope, resulting in a different sediment accumulation pattern and record. The dynamic nature of these two lakes suggests that further analysis on sediment transport and distribution within Arctic lakes is required in order to improve paleoclimatic reconstructions.

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“…Such maps have been used to delineate mass movement features in which the source and depositional areas have an obvious topographic surface expression on the lake bottom (Micallef 2011). Using multibeam bathymetry, small-scale mass movement features have been identified that might not be recognized from a SAP survey (Normandeau et al 2013). Most of the paleoseismic lake studies cited in this paper, however, do not include multibeam bathymetric data.…”

Section: Sub-bottom Acoustic Profiling Surveysmentioning

confidence: 99%

“…This earthquake was interpreted to be the "largest postglacial seismic event of the last ~8000 years in the Kipawa area," as no older slump deposits were recognized within the basin. Normandeau et al (2013) conducted SAP and multibeam bathymetric surveys, and collected shallow cores (0.6 to 1.5 m long) in an investigation of the late Quaternary deposits in Lac St.-Joseph, Quebec (Fig. 6b).…”

mentioning

confidence: 99%

“…An obvious factor contributing to the chronology problem is that only one study (Ouellet and Seguin 1999) collected core longer than 1 -2 m, and a number of the studies did not collect core. The recent studies of Doughty et al (2010) and Normandeau et al (2013) are based on high-density SAP surveys, but only the latter includes a three-dimensional stratigraphy. Paleoseismic research on eastern Canadian lake basins has lacked a sustained focus that would drive the collection of detailed data within a specific area of what is a large region containing a great number of lakes.…”

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confidence: 99%

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An Integrated Stratigraphic Approach to Investigating Evidence of Paleoearthquakes in Lake Deposits of Eastern Canada

Brooks

2015

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Seismic shaking can generate mass movements, turbidites, and soft-sediment deformation within lake basins. These ‘disturbed’ deposits may be preserved, and provide a stratigraphic record of paleoearthquakes. A three-dimensional seismo-stratigraphy of the lake deposits can be constructed from a high-density, sub-bottom acoustic profile (SAP) survey, allowing disturbed deposits within the basin to be identified and mapped. Event layers composed of one or more disturbed deposits can be identified within the seismo-stratigraphy, and targeted coring of the lake deposits provides ground-truthing of the disturbed deposits. Analysis of organic or sediment materials sampled from recovered cores allow ages to be assigned to the event layers. Maps depicting the distribution, extent and types of disturbed deposits within each event layer can be compiled by integrating the event layer stratigraphy and the three-dimensional architecture of the lake deposits. An intrabasin, multi-deposit event layer is the likely signature of significant past earthquake shaking, but possible non-seismic triggers also need to be assessed. An earthquake catalogue spanning 16 000 years for central Switzerland exemplifies the results of an integrated seismo- and chrono-stratigraphic approach to paleoseismic investigation. This approach to the investigation of eastern Canadian lake basin(s) has the potential to significantly augment the eastern Canadian earthquake catalogue. Conversely, the absence of seismically-induced disturbed deposits in SAP profiles and in lake core within a given area can help establish negative evidence of paleoseismicity.RÉSUMÉLes secousses sismiques peuvent provoquer des mouvements de terrain, des turbidites, ainsi que la déformation de sédiments meubles dans les bassins lacustres. Ces dépôts « perturbés » lorsque préservés constituent des archives stratigraphiques de ces paléoséismes. Une sismostratigraphie tridimensionnelle des dépôts lacustres peut être élaborée par sondage acoustique haute densité de sédiment (SAP), permettant ainsi de détecter et de cartographier les dépôts perturbés du bassin. Les couches événementielles composées d'un dépôt perturbé ou plus peuvent être détectées par sismostratigraphie, et le carottage ciblé de dépôts lacustres permet de les valider. L’analyse de matériaux organiques ou de sédiments prélevés à partir des carottes permettent de dater les couches événementielles. Des cartes illustrant la distribution, l'étendue et les types de dépôts perturbés au sein de chaque couche événementielle peuvent être compilées en intégrant la stratigraphie de la couche événementielle et l'architecture tridimensionnelle des dépôts lacustres. Une couche événementielle multi-dépôt est la signature probable d’importants tremblements sismiques anciens, sans perdre de vue que d’autres déclencheurs non sismiques puissent être en cause. Un catalogue de séismes couvrant 16 000 ans d’événements dans le centre de la Suisse illustre les résultats d'une approche sismologique et chrono-stratigraphique intégrée de l’histoire paléosismique. Cette approche d’étude de bassins lacustres de l'Est canadien permet d'augmenter considérablement le nombre de séismes du catalogue de l'Est canadien. Inversement, l'absence de dépôts perturbés induits par séisme dans les profils SAP et dans des carottages d’une zone donnée peut contribuer à constituer une preuve de l’absence de paléosismicité.

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Late-Quaternary morphostratigraphy of Lake St-Joseph (southeastern Canadian Shield): Evolution from a semi-enclosed glacimarine basin to a postglacial lake

Cited by 31 publications

References 87 publications

Buried preglacial fluvial gorges and valleys preserved through Quaternary glaciations beneath the eastern Laurentide Ice Sheet

Buried preglacial fluvial gorges and valleys preserved through Quaternary glaciations beneath the eastern Laurentide Ice Sheet

Sediment dynamics in paired High Arctic lakes revealed from high‐resolution swath bathymetry and acoustic stratigraphy surveys

An Integrated Stratigraphic Approach to Investigating Evidence of Paleoearthquakes in Lake Deposits of Eastern Canada

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