Matachewan dike swarm

The Matachewan dike swarm is a large 2,500 to 2,450 million year old Paleoproterozoic dike swarm of Northern Ontario, Canada. It consists of basaltic dikes that were intruded in greenschist, granite-greenstone, and metamorphosed sedimentary terrains of the Superior craton of the Canadian Shield. With an area of 360,000 km² (140,000 sq mi), the Mistassini dike swarm stands as a large igneous province.