A dike swarm (American spelling) or dyke swarm (British spelling) is a large geological structure consisting of a major group of parallel, linear, or radially oriented magmatic dikes intruded within continental crust or central volcanoes in rift zones.
They consist of several to hundreds of dikes emplaced more or less contemporaneously during a single intrusive event, are magmatic and stratigraphic, and may form a large igneous province.
The largest dike swarm known on Earth is the Mackenzie dike swarm in the western half of the Canadian Shield in Canada, which is more than 500 km (310 mi) wide and 3,000 km (1,900 mi) long.
The primary geometry of most giant dike swarms is poorly known due to their old age and subsequent tectonic activity.
[3][4] Sedimentary clastic dike swarms also exist on Earth; for example in Chile.