The Fernie-Kootenay transition, Banff National Park, Canada: Depositional characteristics of density-induced and combined flows

The Fernie-Kootenay transition (Late Jurassic-Early Cretaceous) occurs in the east of Banff exit, Canada Highway 1 and consists of deformed sequence of dark gray shale alternated with thin-bedded sandstone. The thin-bedded sandstone comprises sharply based-and-topped massive, laminated, or wavy cross-laminated units that mimic classical turbidites. The sharp base of each sandstone bed is commonly characterized by flute and tool marks of plant debris and fluted burrows that show consistent northwestward paleoflow directions. These observations suggest that deposition of the sandstone/shale couplets occurred in well-aerated shallow water environments adjacent to a landmass where occasional storm-generated density-induced undercurrents were prevalent The multiple beds that comprise Bouma-type units are perhaps due to multiple strokes of storms that traveled across the shelf.