Schist
Schist is a metamorphic rock formed when shale is buried deep in the earth’s crust, where it is exposed to very high temperatures and pressures. Schist has a unique appearance and is identified or characterized by many thin layers stacked together. This is called foliation. Schist contains flaky, shiny minerals like micas, and can sometimes contain large crystals like garnets. The thin-layered nature of schist makes it easy to break apart into sheets. It is often used as decorative or building stone.
Where is it found?
In Manitoba, schist is found in rock outcrops on the Canadian Shield. A popular fishing spot where you can see schist sparkling in the sun along the lakeshore is at Schist Lake near Cranberry Portage. Some of the best-exposed schist outcrops in Manitoba are found in the Snow Lake area where large crystals of the mineral staurolite can be seen. Rocks in the Snow Lake area are part of the Flin Flon belt, a century-old mining district of historic and ongoing value to Manitoba’s economy. Two billion years ago, this area of Manitoba was a dynamic landscape of active volcanic islands surrounded by oceans. Violent volcanic eruptions, land slides and ocean mud created ample material for forming shale. These volcanic arcs were later stitched together. Today, the low rolling hills around Snow Lake represent the roots of these ancient volcanoes where outcrops of shining schist record the intense metamorphic processes that once fused these volcanoes together.
