Pre-Mississippian History of the Peace River Arch

ABSTRACT The Precambrian basement underlying the area along the Peace River in western Alberta was warped up in post-Cambrian time to form the Peace River Arch. Block-faulting accompanied the crustal movements. The basement remained high during much of the Paleozoic era and during Upper Devonian time formed an island about which an extensive fringing reef complex developed. The island was submerged towards the close of the Devonian. The Arch was further disturbed by faulting at the close of the Paleozoic and since then has been tilted to the southwest. Basal Paleozoic sands and Devonian carbonates provide excellent reservoirs over and surrounding the Arch. Commercial pools have been discovered in Devonian reefs.