North Atlantic Craton

The North Atlantic Craton is a block of Archaean continental crust, more than 2.5 billion years old, now exposed in three separated regions: southern West Greenland, the Nain Province of Labrador, and the Lewisian complex of northwestern Scotland. In Greenland it consists mainly of tonalite-trondhjemite-granodiorite orthogneisses along with supracrustal belts, anorthosite complexes, and granite intrusions, bounded by the Nagssugtoqidian orogen to the north and the 1.8 to 1.87 billion year old Ketilidian-Makkovik mobile belt to the south. The craton was assembled from several colliding terranes between about 2,950 and 2,580 million years ago and later experienced kimberlite-forming magmatism in two episodes, one in the Neoproterozoic around 600 to 550 million years ago and another in the Jurassic around 200 to 150 million years ago. Its present fragments were separated roughly 60 million years ago when the Labrador Sea opened, splitting the once continuous craton between Greenland, Canada, and Scotland.