Mackenzie dike swarm
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The Mackenzie dike swarm, also called the Mackenzie dikes, form a large igneous province in the western Canadian Shield of Canada. It is one of more than three dozen dike swarms in various parts of the Canadian Shield and is the largest dike swarm known on Earth,[1] more than 500 kilometers (311 miles) wide and 3,000 kilometers (1,864 miles) long, extending in a northwesterly direction across the whole of Canada from the Arctic to the Great Lakes. The mafic dikes cut Archean and Proterozoic rocks, including those in the Athabasca Basin in Saskatchewan, Thelon Basin in Nunavut and the Baker Lake Basin in the Northwest Territories.
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[edit] Geographical extent
Vast volumes of basaltic lava paved over a large area in the western Canadian Shield in the form of a flood basalt event. The massive eruptive event occurred during the Proterozoic period about 1,267 million years ago. Today the thickness of these flood basalts range from 2,000 to 3,500 m and consists of about 150 flows, each about 10-25 m thick which are part of the Copper Creek Formation. Except for the lowermost flows, which contain evidence of interaction with water, the entire sequence was erupted subaerially. Eruption of plateau lavas near the Coppermine River, built an extensive volcanic plateau about 1,200 million years ago with an area of about 170,000 km² (65,000 sq mi) representing a volume of lavas of at least 500,000 km³ (120,000 mi³).
[edit] Origin and history
The source for the Mackenzie dike swarm is considered to be a mantle plume center called the Mackenzie hotspot. At ca. 1.269-1.267 Ga, the Slave craton was partly uplifted and intruded by the giant Mackenzie dike swarm. This was the last major event to affect the core of the Slave craton, although later on some younger mafic magmatism registered along its edges.
[edit] See also
[edit] References
- ^ Supressing Varying Directional Trends Retrieved on 2007-07-28
