February 2012
Inventory of Aggregate Resources for the Region of Salluit, Nunavik, Québec
André Brazeau
Guillaume Allard
The village of Salluit is located in the extreme north of Nunavik, approximately 10 kilometres from Hudson Strait (figures 1 and 2). Its population (approximately 1300 in habitants) is growing rapidly, just like that of Nordic villages in general. For this reason the need for housing and municipal infrastructure is very high. The presence of continual permafrost combined with global warming makes the construction of these infrastructures more difficult.
Click on image to enlarge |
Click on image to enlarge |
The demand for aggregates for the construction of raft foundations foundations for buildings and roads) is all the more important (figure 3) and the need for an inventory is becoming obvious
The narrow valley of Salluit is surrounded by mountains and avalanche corridors to the east and west, a fjord to the north and a rocky hummock to the south. The end of the valley consists mainly of soft sediment rich in ice which, when thawing, creates different settlements in the land. This valley is wedged between the mountain sides which rise to almost 250 meters above sea level (figure 4). |
The superficial deposits are mainly located in the valley while on the topographic heights, the sediments is generally thin or non-existent. The deposits are essentially composed of sediment which is glacial, glaciofluvial, marine, fluvatile, gravity and organic. The till is generally rich in boulders and stones with a silty-sandy matrix. The glaciofluvial deposits are composed of average-to large-grain sand, gravel and, in general, rounded pebbles. The marine deposits cover a good portion of the end of the valley under an altitude of 150 meters. Following the melting of the continental glaciers, the Arctic Ocean waters flooded land still sunken by the passage of the glacier. In fact, the deglaciation of the territory in approximately 7900 BP (Kasper and Allard, 2001) was quickly followed by a marine overlap. The postglacial sea in the region was called the “Iberville Sea” by Laverdière (1969). The Iberville Sea waters spread out over the Salluit area up to an altitude of 150 meters. Thereafter, the progressive retreat of the sea at the rate of the isostatic rebound controlled the different surface deposits that we find today in the Salluit Valley (L’Hérault, 2009). The marine deposits are sometimes covered by more recent deposits such as the colluvial deposits at the foot of the slopes and coastal sand deposits near the coast.
The main sources of aggregates are contact glaciofluvial deposits and deltaic marine deposits.
Intervention of the MRNF
The results of the inventory enabled the localizing and characterization of aggregate sources and evaluated their extent and quality.
Field activities consisted mainly of numerous sampling with a shovel and visiting natural cutting and several sand quarries. The granular deposits were delineated by aerial photographs. Furthermore, several sand or gravel samples were taken and sent to the laboratory to determine their physico-mechanical properties.
Results
This work enabled two large granular deposits several kilometres to the south of the village to be characterized (figure 5, boxed in orange). According to the different standards established by the ministère des Transports, the quality of the material in the region is very good. According to their intrinsic characteristics, the coarse aggregates meet the standards of categories 1 and 2 while the sand complies with the standards of category 1. Coarse aggregates (>5 mm) consist mainly of granite rock fragments and metamorphic rocks. The fine aggregate (<5 mm) is sand which comes from granite rocks (quartz, feldsparth, black mica). Sand is generally medium to coarse grain. |
The exploitation of these aggregate resources will allow the needs of construction to be met for residential and community areas. Moreover, over the next few years, it is important to ensure the expansion of the village towards the south and to build an access road so as to allow residential development.
References
L’Hérault, E., 2009. Contexte climatique critique favorable au déclenchement du ruptures de mollisol dans la vallée de Salluit, Nunavik, Mémoire de maîtrise Master’s thesis, Université Laval, 150 pages.
Laverdière, C., 1969. Mer d’Iberville, Revue de géographie de Montréal, Montréal, XXIII (3) : 358 pages.
Kasper, J. N. and et M. Allard. 2001. “ Late-Holocene climatic changes as detected by the growth and decay of ice wedges on the southern shore of Hudson Strait, northern Québec, Canada. ” Holocene, volume 11 (5): pages 563-577.
