CGRG Bibliography of Canadian Geomorphology
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Author : Cauchon-Voyer, G.; Locat, J.; Demers, D.; Robitaille, D.; and Locat, P.
Date : 2008.
Title : Morphological and stratigraphic analysis of the Cap Colombier landslide area, Québec.
Publication : 4th Canadian Conference on Geohazards: From Cause to Management. May 20-24, 2008. University Laval, Quebec City, Quebec.
Issue :
Page(s) :
Abstract
A 6.5 km2 subaerial landslide scar is identified in the emerged late Quaternary sediments located west of the Betsiamites River deltaic system at Cap Colombier, Québec. At least two distinct failure events created the scar. A morphological and stratigraphic analysis of the Cap Colombier landslide area has been initiated in order to define the characteristics of the slope failure events. Integration of piezocone data and results from seismic reflection and refraction surveys on land led to the recognition of a complex stratigraphy resulting from deltaic progradation during the last relative sea-level regressive phase and subsequent landslide events. The analysis integrates also the submarine morphology and stratigraphy previously described for the area. The eastern part of the subaerial scar is associated to a retrogressive landslide event that followed the 1663 earthquake. It is characterized by large rotated blocks, lobes and water filled depressions. The 1663 failure most likely occurred on land and the debris reached underwater up to 10 km from the main body of the subaerial landslide. The western flank of the scar is leveled and probably related to an older event dated around 7 kyr. The older headscarp is located on land at about 60 m of elevation, which corresponds to the level of an emerged marine terrace. The lateral flanks reach underwater to depths down to 140 m below sea level, making this 80 km2 subaerial and underwater scar the largest landslide yet to be identified in Quebec.
Bibliography of Canadian Geomorphology