Late-stage contractional orogenesis commonly involves a component of extensional collapse, due to crustal overthickening, but extension is thought to affect primarily the upper parts of the system. The Grenville province of southern Ontario exposes deeper structural levels of a mid to late Proterozoic collisional orogeny, and recent results indicate that this deeper portion also underwent significant late-stage extension. This study will examine additional ductile shear zones that occur in the Grenville in this area in order to test the idea that late-stage extension is a fundamental component of Orogenic architecture in both shallow and deep structural positions.
