The Fort St. John Graben, Western Canada

Abstract

The Fort St. John Graben (FSJG) is a regional-scale, west-trending, fault system located at the center of the Peace River Embayment of the Western Canada Sedimentary Basin (Fig. 11.1). The FSJG forms the central arm of a larger fault system known as the Dawson Creek Graben Complex which was filled with sediments in several stages during Carboniferous to Permian times (Figs. 11.2–11.4), Barclay et al. 1990). Although the Dawson Creek Graben Complex was formed during a long period of extension, its bounding fault systems often display alternate zones of both compressional and extensional structural styles. The unique structural characteristics of the graben complex have been attributed to Carboniferous to Permian strike-slip faulting as well as to late reactivation and inversion processes associated with the development of the nearby Rocky Mountain Fold and Thrust Belt (R.D. Oggy, pers. comm.).