SAINT-LOUIS DE GONZAGUE AND GRANDE-ÎLE QUARRIES
The Saint-Louis de Gonzague quarry is located on the south-shore of the Beauharnois Canal. The Grande-Île quarry is located in the western sector of the Salaberry Island, in Valleyfield, Quebec.
Rock from these quarries is composed mainly of dolomite which characterizes the Beauharnois Formation of the Beekmantown Group, whose lower Ordovician age approximates 460 to 490 million years old.
Dolomites are sedimentary rocks formed under tropical climates, in shallow marine and lacustrine environments. These formations are the result of the evaporation of magnesium-rich water sources from which crystals accumulate and cement together on the bottom of the basin to form dolomites. These quarries’ dolomites also contain very hard, small, rounded quartz grains that increase the quality of aggregates. These grains come from the erosion and transportation of rocks polished by one another, that settle and merge with other crystals contained in the dolomite.
Dolomites can also form in a marine environment through the progressive replacement, by dolomite, of the calcite contained within limestone.
