Pink Lake occupies a crystalline limestone bedrock basin of precambrian age, along the southern boundary of the Canadian Shield. The landscape surrounding the lake is rugged with local relief up to 30m above the lake. The water in Pink Lake is alkaline due to the surrounding limestone bedrock, Carbonates are precipitated in shallow water annually during the summer months. There is evidence of one glaciation in the area, the last one which is the Wisconsin.

Map of Gatineau Park, Quebec