Age of Landslides Along the Grande Rivière de la Baleine Estuary, Eastern Coast of Hudson Bay, Quebec (Canada)

Abstract

Landslides are widespread in tectonically active zones, in mountains and in areas where fine-grained deposits predominate, particularly in lowlands influenced by postglacial marine transgression. Late and postglacial marine clays in Norway (Bjerrum 1954a, b) and eastern Canada (La Rochelle et al. 1970; Leroueil et al. 1983) are particularly prone to multiple rotational slips (Hutchinson 1968). Identification of causal processes involved in landslide activity has been discussed by several workers (Sharpe 1938; Terzaghi 1950; Varnes 1958; Selby 1982). In such an attempt one must be able to distinguish between direct and indirect causes. In general, the direct causes were more easily identified, as for example seismic or volcanic activity, oversteepening of slopes undercutting at the toe of a slope by stream action, fluctuations in depth of water bodies, prolonged rainfall, storm surges or rapid snow melting, and overloading of surfaces. While the inherent characteristics of deposits (lithologies, weathering states) and slope were considered as prerequisites for sliding occurrence, climate influence has been generally identified as an indirect cause.