 However, whether the Eastern Slave was the result of rifting or the accretion of another terrane is still up for debate.Following the 2.7 Ga rifting or accretion event, the Slave underwent large scale extension at 2680 Ma resulting in the formation of the > 400x800 km Burwash Basin, widespread mafic sills, and other younger turbidites along the northwestern margin.The Burwash Basin consists of turbidites interbedded with felsic to indermediate volcanic tuff.