Slave–Churchill collision tectonics

Abstract

THE analogue model^1–4 of plane indentation⁵ is applied qualitatively here to the proposed collision⁶ of the Slave craton (last major deformation ∼ 2,500 Myr ago) and the western Churchill craton (last major deformation ∼ 1,740 Myr ago) of the Canadian Shield. The model successfully predicts several large-scale deformational features of the collision zone. McKenzie¹ has drawn an analogy between the collision of the African plate (Arabian shield) with the Eurasian plate and the impaction of a hard die on a soft piece of metal. He concluded that when salients of an approaching continent meet an Andean-type margin of another continent, further lithospheric consumption is not possible due to the buoyancy of continental crust^1,7 and either the crust of the underthrust continent is thickened, or two or more small plates (such as the Turkish, Aegean and Iranian plates) are formed and are pushed aside to permit further convergence, or both processes occur¹.