ABSTRACT: Observations geomorphologies sur les mega-blocs du sector sud-est de la batture argileuse de la Baie a l'Original, au Parc du Bic, Bas-Saint-Laurent (Quebec) [Geomophologic observations on mega -boulders in the southern area of the clayey tidal-flat of the Baie a l'Original, au Parc du Bic, Bas-Saint-Laurent (Quebec)].

CGRG Bibliography of Canadian Geomorphology
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Abstract

Many mega-boulders are scattered on the clayey tidal flat in the Parc du Bic, on the south shore of the lower St. Lawrence estuary. Of the 160 boulders measured,46.3% are erratics from the Laurentian Shield on the north shore, and 53.7% are Appalachian clasts mainly from the coastal rock ridges on the south shore. All boulders measured exceeded 100 cm and the weight of the smallest (a Precambrian) was one metric ton whereas the largest (an Appalachian) weighted 76 tons and measured 565 x 350 x 205 cm. Most mega-boulders resting on the surface of the tidal flat are likely to be moved freely by ice blocks. Those in the low marsh are more exposed and move more frequently. Evidence of displacement has been observed for 32% of the mega-boulders in the low marsh; the longest displacement of a gneiss boulder weighing 6 toms was 6 m.

Bibliography of Canadian Geomorphology