Imbricate architecture of the upper Paleozoic to Jurassic oceanic Cache Creek Terrane, central British Columbia

Upper Paleozoic to Lower Jurassic oceanic rocks of the Cache Creek Terrane near Fort St. James, in central British Columbia, form a stack of thrust sh eets cut by steeply dipping strike-slip faults. Paleontologically dated upp er Paleozoic strata include bioclastic shallow-water limestone and ribbon c hert. Isotopically dated Permian rocks consist of tonalite sills and stocks and rhyolite flows intercalated with basalt flows. Paleontologically dated lower Mesozoic rocks include greywacke, sandstone, siltstone, argillite, r ibbon chert, conglomerate, limestone, and basalt tuff. Trembleur Ultramafit e unit of the Cache Creek Complex, in places part of an ophiolite suite, fo rms thrust sheets and klippen that overlie lower Mesozoic sedimentary rocks . Sedimentological, lithochemical, paleontological, petrological, and textu ral comparisons with other areas and established models demonstrate that Ca che Creek Terrane is an accretionary complex, a structurally stacked assemb lage of rocks that originated in diverse and disparate oceanic paleoenviron ments. These environments include spreading ridge, oceanic plateau, atoll, trench fill, and possibly arc. Internal imbrication of the terrane is as yo ung as Early Jurassic, as determined from fossil evidence, and the minimum age of obduction of the thrust stack westward onto Stikine Terrane is Middl e Jurassic, as determined from dating of a crosscutting pluton. Triassic bl ueschist and eclogite of Cache Creek Terrane are interpreted to have been p rimarily uplifted to upper crustal levels during Triassic subduction. Cache Creek Terrane, as a remnant of that subduction process, and caught in the collision between Stikine and Quesnel terranes, marks the position of a lit hosphere-scale suture zone, the Pinchi Suture.