Volume 1 - Main Report

Proximal Glaciomarine Deposits
The core holes indicate a unit composed of silty sand with a proportion of 15 % to
20 % gravel and boulders, resting discordantly on bedrock. The thickness of this unit
ranges from 0.6 to 14 m (Stantec, 2011; 2012). This unit was sedimented at the very
beginning of the marine invasion of the Iberville Sea, when the front of the ice sheet
was located near Deception Bay, a little farther south of the study zone. This type of
deposit does not outcrop on the surface of the study site.
Distal Glaciomarine Deposits
Distal glaciomarine deposits were sedimented from the time the level of the
postglacial Iberville Sea reached its maximum altitude, i.e. 123 m relative to the
current mean level, and thus less than 8,900 years BP 4 (Gray et al., 1993)
(Map 6.2). These clayey silt deposits were sedimented in calm deep water. The core
hole results also indicate that the thickness of this unit may reach 20 m
(Stantec, 2012). According to the visual characterizations and the geotechnical tests
conducted, these clays have a very soft consistency and no bearing capacity
(Golder, 2007; Stantec, 2011; 2012).
The glaciomarine clay unit generally outcrops on the surface of the seabed. The
divers’ visual description, the description of the sediment core samples and the
granulometric results show that the clay layer largely outcrops at sites Q1 and Q2
(Appendix 4). On the terrestrial portion of the study zone, the glaciomarine clay
appears completely east of the study zone in the Deception River Valley (Map 6.2).
Delta and Shoreline Deposits
The delta deposits are the deposits abandoned by the watercourses when they flow
into the sea. They are mainly composed of sand and gravel. However, boulders of
metric size may also be found there. These deposits are identified in the river valley
of Bombardier Beach (Map 6.2). This delta, sedimented when the sea level was
higher than at present, extends northwest of the Deception Bay shoreline (Map 6.2).
It is divided by many terraces formed by downcutting of the river when the sea level
fell. The presence of these terraces allows us to affirm that these deposits may be
over twelve metres thick and cover the glaciomarine clay deposit units.
4
BP = Before Present
Canadian Royalties Inc.
GENIVAR
101-53046-02 November 2012
55