Since middle Proterozoic time, two long-lasting phases affected the Canadian Arctic Archipelago, each forming a different sedimentary basin. The Franklinian Basin, which was floored by continental or quasi-continental crust, received 10 km or more of clastic, carbonate and volcanic rocks from the mid-Proterozoic to Devonian. Internal parts of the basin were deformed, intruded and metamorphosed locally, and external parts were folded and thrust cratonward by compressional episodes of the Ellesmerian Orogeny, which culminated in the late Devonian. This marked the end of a phase, at which time the entire region may have been emergent. The nature of plate interactions that produced Ellesmerian deformation are unknown. The second phase began in the early Carboniferous, when plate movements of the Boreal Rifting Episode created the proto-Canada Basin by left-hand transform motion of a plate along the modern continental margin and the location of the Kaltag Fault of northern Alaska. As a marginal side effect of that motion, the Sverdrup Basin developed as a peri-cratonic incipient rift. From the Carboniferous to late Cretaceous the basin received about 13 km of cratonic-derived clastic detritus. From late Cretaceous to early Tertiary time, the Arctic Archipelago was disrupted by the interference of two plate movements originating in the Arctic and North Atlantic regions. Those events had three main effects: the craton was extended and a grabenfilled depression formed in the southeastern part of the archipelago; the eastern and central parts of the Sverdrup Basin were compressed and uplifted (Eurekan Orogeny); and resultant clastics prograded northwestward toward the Canada Basin, to form the Arctic continental terrace wedge.