Grenville dike swarm

The Grenville dike swarm is a large Proterozoic dike swarm in the Canadian provinces of Ontario and Quebec. It is one of the several major magmatic events in the Canadian Shield and it possibly formed 590 million years ago along a triple junction that might have been related to a mantle plume. The maximum length of the Grenville dike swarm is 700 km.

The Ottawa-Bonnechere Graben is associated with the Grenville dike swarm, as some of its features date from that time.