Évolution morpho-sédimentaire de la barre de déferlement : un exemple dans le golfe du Saint-Laurent, Québec

Ross, Nathalie; Long, Bernard

doi:10.7202/032790ar

Cited by 2 publications

(2 citation statements)

References 17 publications

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“…The cliff of Rivière Saint‐Jean is southwest facing with fetches from the WSW (230 km) and the SW (120 km). Swells at this site have average periods of 6 to 8 s, mean wave heights of 2 m and storm wave heights of 5 m (Ross and Long, ). Tides are semi‐diurnal with a mean height between 1.7 m (mean tides) and 2.5 m (spring tides) at the tide gauge of Mingan, located 30 km east of the study area (Fisheries and Oceans Canada, ).…”

Section: Regional Settingmentioning

confidence: 99%

Calculating Lateral Frost Front Penetration in a Rapidly Retreating Cliff of Fine Sediments

Boucher‐Brossard

Bernatchez

Corriveau

et al. 2015

Permafrost and Periglac. Process.

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An adapted version of the Stefan equation (CLIFFSE) was tested to predict lateral progression of the frost front into cohesive sediments that form coastal cliffs along the north shore of the maritime estuary and gulf of the St Lawrence River (Quebec, Canada). The equation was adapted to accommodate the influence of cliff erosion on lateral penetration of freezing and thawing into vertical cliff faces. As the cliff erodes, freezing and thawing are initiated from the newly revealed surface. Frost progression and erosion were measured with an automated thermal erosion pin system. Measured observations agreed with predictions from the adapted equation (78 to 99% of the variability explained). Erosion associated with thawing front progression during winter warm spells led to a relative reduction in the frost front depth. Subsequently, progression of the frost front into the cliff contributed to an additional 50 cm of sediment freezing and erosion by the end of the cold season, which was not predicted by the original Stefan equation. Our findings support the hypothesis that multiple warm spells influence the amount of lateral penetration of the frost front in vertical cliffs.

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Section: Regional Settingmentioning

confidence: 99%

Calculating Lateral Frost Front Penetration in a Rapidly Retreating Cliff of Fine Sediments

Boucher‐Brossard

Bernatchez

Corriveau

et al. 2015

Permafrost and Periglac. Process.

View full text Add to dashboard Cite

show abstract

“…Fetch from the Gulf of St. Lawrence is from the west-southwest (230 km) or the south-west (120 km). Swells have a period of 6 to 8 s and offshore mean wave height is 2 m, but can reach more than 5 m during storms [57]. The area is exposed to semidiurnal tides ranging between 1.5 m (mean tides) and 2.4 m (spring tides) at the tide gauge of Mingan, located 30 km east of the study area [58].…”

Section: Regional Settingmentioning

confidence: 99%

Long-Term Evolution and Monitoring at High Temporal Resolution of a Rapidly Retreating Cliff in a Cold Temperate Climate Affected by Cryogenic Processes, North Shore of the St. Lawrence Gulf, Quebec (Canada)

Bernatchez

Boucher‐Brossard

Corriveau

et al. 2021

JMSE

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This article focuses on the quantification of retreat rates, geomorphological processes, and hydroclimatic and environmental drivers responsible for the erosion of an unconsolidated fine-sediment cliff along the north shore of the Gulf of St. Lawrence (Quebec, Canada). Annual monitoring using field markers over a period of twenty years, coupled with photo interpretation and historical archive analysis, indicates an average annual erosion rate of 2.2 m per year between 1948 and 2017. An acceleration in retreat occurred during the last 70 years, leading to a maximum between 1997 and 2017 (3.4 m per year) and 2000–2020 (3.3 m per year). Daily observations based on six monitoring cameras installed along the cliff between 2008 and 2012 allowed the identification of mechanisms and geomorphological processes responsible for cliff retreat. Data analysis reveals seasonal activity peaks during winter and spring, which account for 75% of total erosional events. On an annual basis, cryogenic processes represent 68% of the erosion events observed and subaerial and hydrogeological processes account for 73%. Small-scale processes, such as gelifraction, solifluction, suffosion, debris collapse, and thermoabrasion, as well as mass movement events, such as slides and mudflows, induced rapid cliff retreat. Lithostratigraphy and cliff height exert an important control on erosion rates and retreat modes, which are described by three main drivers (hydrogeologic, cryogenic, and hydrodynamic processes). Critical conditions promoting high erosion rates include the absence of an ice-foot in winter, the absence of snow cover on the cliff face allowing unrestricted solar radiation, the repetition of winter warm spells, snow melting and sediment thawing, and high rainfall conditions (>30 mm or SPI > 2). The relationships between hydroclimatic forcing and retreat rates are difficult to establish without taking into account the quantification of the geomorphological processes involved. The absence of quantitative data on the relative contribution of geomorphological processes can constitute a major obstacle in modeling the retreat of cliffs with regard to climate change.

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Évolution morpho-sédimentaire de la barre de déferlement : un exemple dans le golfe du Saint-Laurent, Québec

Cited by 2 publications

References 17 publications

Calculating Lateral Frost Front Penetration in a Rapidly Retreating Cliff of Fine Sediments

Calculating Lateral Frost Front Penetration in a Rapidly Retreating Cliff of Fine Sediments

Long-Term Evolution and Monitoring at High Temporal Resolution of a Rapidly Retreating Cliff in a Cold Temperate Climate Affected by Cryogenic Processes, North Shore of the St. Lawrence Gulf, Quebec (Canada)

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