The Marathon Large Igneous Province is a

Paleoproterozoic The Paleoproterozoic Era (;, also spelled Palaeoproterozoic), spanning the time period from (2.5–1.6 Ga), is the first of the three sub-divisions ( eras) of the Proterozoic Eon. The Paleoproterozoic is also the longest era of the Earth's ...

large igneous province A large igneous province (LIP) is an extremely large accumulation of igneous rocks, including intrusive (sills, dikes) and extrusive (lava flows, tephra deposits), arising when magma travels through the crust towards the surface. The formation ...

along the southern Superior craton of

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central C ...

, Canada, located around the northern margin of

Lake Superior Lake Superior in central North America is the largest freshwater lake in the world by surface areaThe Caspian Sea is the largest lake, but is saline, not freshwater. and the third-largest by volume, holding 10% of the world's surface fresh wa ...

. It consists of three diabase

dike swarm 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 ...

s known as Marathon, Kapuskasing and Fort Frances. The Kapuskasing and Marathon dike swarms range in age from about 2,126 to 2,101 million years old while the Fort Frances dike swarm is between 2,076 and 2,067 million years old. A single, periodically active

mantle plume A mantle plume is a proposed mechanism of convection within the Earth's mantle, hypothesized to explain anomalous volcanism. Because the plume head partially melts on reaching shallow depths, a plume is often invoked as the cause of volcanic hot ...

was responsible for the creation of the Marathon Large Igneous Province due to the lack of apparent

polar wander Polar wander is the motion of a pole in relation to some reference frame. It can be used, for example, to measure the degree to which Earth's magnetic poles have been observed to move relative to the Earth's rotation axis. It is also possible to use ...

during the formation of the igneous province. The large magmatic event covers an area of at least and the entire large igneous province was constructed in 60 million years.

References

Igneous petrology of Ontario Large igneous provinces Dike swarms Paleoproterozoic magmatism Lake Superior {{Canada-geology-stub