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Today’s Canyon Sainte-Anne is the result of a combination
of factors acting over
several million years. The river still continues its patient sculpture work.
It all started in the Precambrian Age (1.2 billion years ago) when
hard rock formed the canyon's walls and bottom. This metamorphic rock,
called granitic gneiss, was formed at high pressure in the extremely
hot depths of earth then rose to the surface through movements in
the earth's crust. A bit later, a second rocky mass appeared, the
sedimentary Palaeozoic rock formed some 450 million years ago by the
compression of underwater sediments.
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Much later, two successive ice ages covered North America. It is during
the melting of the second one led to the formation of the current
hydrographic system (St. Lawrence River, Orleans Island, and the Magdalene
Islands, as well as all the rivers known today). Erosion then finished
the job by changing the general appearance of the region.
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