The term Racklan Orogen is applied to an extensive region of deformed rocks that underlies northwestern Canada. At least one period of deformation predated extrusion of the ca. 1267–1270 Ma basalt of the Coppermine River Group, and at least two periods of deformation postdated extrusion of the Coppermine basalt. Limits on the age of deformation can be confidently placed between 1663 Ma (the age of the Narakay volcanic complex that postdates uppermost strata of the Hornby Bay Group) and 1100–800 Ma (the maximum age of the Mackenzie Mountains Supergroup).

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