Radiolarian biostratigraphy and implications, Cache Creek Group of Fort Fraser and Prince George map areas, central British Columbia

As part of the new Nechako NATMAP project, radiolarian investigations from the Fort Fraser (93K) and Prince George (93G) map areas in central British Columbia provide control on the age and structures of the Cache Creek Group and related units. Twenty-five localities of radiolarian chert, siliceous mudstone, limestone, and chert-bearing conglomerate from the Cache Creek Group and the Sifton Formation range in age from late Pennsylvanian-early Permian to Early Jurassic (Pliensbachian). These results provide a new stratigraphic framework for the area. In central British Columbia, Cache Creek Group upper Paleozoic rocks include limestone, chert, and basalt, and may include gabbro and ultramafics, and Mesozoic rocks include greywacke, siltstone, argillite, limestone, and basalt tuff. Regionally, these results give new information for correlations within the Cache Creek Terrane as a whole, for instance about transitional intervals of sedimentation from carbonate to chert and chert to hemipelagics.