ABSTRACT: Lithologie des cailloux de la Baie de Metis, rive sud de l'estuarie maritime du Saint-Laurent (Quebec): un example du transport glaciaire et glaciel complexe [Lithology of boulders at Mitis Bay, south shore of the Lower St. Lawrence Estuary: an example of composite glacial and glaciel transport].

CGRG Bibliography of Canadian Geomorphology
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The lithology of boulders forming intertidal pavements and barricades in the Mitis Bay, is composed of 40% Precambrian, 25.8% ‘gres', 18.3% shale (including slate, mudrock and clayrock), 11.5 limestone, 3.6% quartizite and 0.8% conglomerate. This average is based on 53 countings for a total of 29,932 clasts. In the Precambrian category, anorthosite boulders, a lithology occurring only in the Laurentidian Shield, account for 0.8%. In the shale category, 1.6% of the clasts are red slates. Corral limestone and dolostone boulders were also observed. The source of the Precambrian clasts is most likely the Laurentidian Shield on the north shore of the Saint Lawrence estuary over 55 km away, while boulders of sedimentary lithologies belong to the Cambro-ordovician formations in the coastal zone of the south shore and of the Silurian formations over 35 km inland to the SE of the Mitis Bay area. Except for boulders of proximal or local origin, most others have been transported over many tens of kilometres and sometimes over 100 km by Appalachian and Laurentidian glacier ice. Because most boulders are found in marine clay deposits, final deposition is attributed to icebergs. This study clearly demonstrates the importance of icebergs as a sedimentary agent during the first millennia of the Goldthwait Sea.

Bibliography of Canadian Geomorphology