CGRG Bibliography of Canadian Geomorphology
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Author : Dionne, J-C.
Date : 1996
Title : The lower terrace at Petite-Riviere (Charlevoix area) : Evidence for neotectonic activity during the Holocene
Publication : Geographie physique et Quaternaire
Issue : 50(3):
Page(s) : 311-330
Abstract
The lower terrace at Petite-Riviere is a component of the Mitis terrace on the north shore of the St. Lawrence estuary. It is composed of two segments located apart from Rivi re de la Martine, and respectively 2.3 and 5.2 km long, and 50 to 300 m wide. The terrace is 6 m a.s.l. in the NE segment and 8-10 m in the SO segment. This polygenic landform resulted both from erosion and deposition. The substrate was cut into various Wisconsinan deposits (till, glaciolacustrine sand, silty-clay varves) and bedrock (Ordovician shales). The surficial unit is a stratified silty fine sand deposited in a former upper tidal marsh. Although minor lithostratigraphic differences do exist, both segments differ in age. The median age (N-24) of the tidal deposit in the SO segment is 2000+/-50 BP. This age is in agreement with the median age of the Mitis terrace (2080+/-60 BP) elsewhere along the St. Lawrence estuary, while the median age is only 770+/-40 áBP (N -26) in the NE segment. Age difference between the two segments of the lower terrace is attributed to neotectonic activity related to the seismic character of the Charlevoix area.
Bibliography of Canadian Geomorphology