The Precambrian shield forms Saskatchewan's bedrock formations. It resembles a jigsaw puzzle made up of five continental landmasses created 4.5 to 2.5 billion years ago (Archean Eon). Between these are zones of rocks that formed on or below the ocean floor about 2.5 to 0.5 billion years ago (Proterozoic Eon). This tectonic assembly, which included closure of the former Manikewan Ocean (to produce the now present Reindeer Zone), was complete by about 1.8 billion years ago, after which time the area we know as Saskatchewan remained a single and relatively stable land mass.(Image-top) 1900 to 1875 million years ago. (Courtesy of Royal Saskatchewan Museum) (Image-middle) McIlvenna Bay deposit at Hanson Lake. (Courtesy of NOAA) Black smokers, our understanding of the geological past is helped by studying processes taking place on Earth today. Black smokers, located along some plate boundaries in the ocean, are responsible for the formation of mineral deposits, and have been for billions of years. (Image-bottom) Present Day Northern Saskatchewan: A jigsaw puzzle of continental plate |