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TitreGeomorphological characteristics and variability of Holocene mass-transport complexes, St. Lawrence River Estuary, Canada
AuteurPinet, N; Brake, V; Campbell, C; Duchesne, M
SourceGeomorphology vol. 228, 2015 p. 286-302, https://doi.org/10.1016/j.geomorph.2014.09.008
Année2015
Séries alt.Secteur des sciences de la Terre, Contribution externe 20140152
ÉditeurElsevier BV
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1016/j.geomorph.2014.09.008
Mediapapier; en ligne; numérique
Formatspdf
ProvinceQuébec
SNRC21M/09; 21M/16; 21N/05; 21N/11; 21N/12; 21N/13; 21N/14; 22B/12; 22B/13; 22B/14; 22B/15; 22C; 22F/01; 22F/02; 22F/08; 22G/02; 22G/03; 22G/04; 22G/05; 22G/06
Lat/Long OENS -70.7500 -66.5000 49.5000 47.2500
Sujetstransport des sediments; glissements de terrain; bathymétrie; morphologie; géophysique; géologie générale; géologie marine; géologie des dépôts meubles/géomorphologie
Illustrationslocation maps; bathymetric profiles; seismic reflection profiles; 3-D models; tables; graphs; histograms
ProgrammeLa géoscience pour les développements extracôtiers de la côte est, Géoscience en mer
Résumé(disponible en anglais seulement)
Recently acquired multibeam bathymetry data are used to investigate seafloor instability features along a 310 km-long segment of the St. Lawrence River Estuary. The analysis of this dataset indicates that submarine slides occur over a much larger area than previously recognized and that Holocene sediments are reworked by mass-transport along significant portions of both the northwest and southeast margins of the Laurentian Channel. In the surveyed area, 96 individual mass-transport complexes (MTCs) were identified representing 13% of the seabed. MTCs vary in area from less than 1 km2 to more than 40 km2 and exhibit various geomorphological signatures. Qualitative observation reveals an apparent disparity between MTCs that remain coherent and those that disintegrate during downslope transport evolving into a blocky morphological signature. For allMTCs, morphological parameters have been measured (area, length, and height) or calculated (slope and roughness). This quantitative analysis provides a unique opportunity to study these parameters in a statistically significant and homogeneous dataset located in a relatively small area that experienced a similar Quaternary history. In many cases, mass transport events appear to initiate in the vicinity of steep bedrock walls located along some segments of the estuary. The timing of mass-transport events was not constrained during this study. However, the fact that the region hosts the Charlevoix seismic zone, the most tectonically active area in eastern Canada, strongly suggests that earthquakes acted as a trigger for submarine landsliding.
Résumé(Résumé en langage clair et simple, non publié)
Cette étude, basée principalement sur des données bathymétriques haute-résolution, présente les résultats de la cartographie des glissements sous-marins dans l'estuaire du Saint-Laurent. Quatre-vingt-seize glissements sous-marins représentent 13% du fond marin de l'estuaire. Une attention particulière est portée aux caractéristiques morphologiques variées des glissements. Les facteurs favorisant les glissements (incluant les séismes) sont examinés. Bien que pas formellement discuté, les risques associés aux glissements sous-marins dans cette région fortement peuplée apparaissent clairement à la lecture de l'article.
GEOSCAN ID295072