Estuarine channel fills in the Upper Cretaceous Dunvegan Formation: core example

The Upper Cretaceous Dunvegan Formation of western Alberta has been subdivided into seven allomembers (A to G), each separated by widespread transgressive flooding surfaces.

Wave-dominated, deltaic, depositional systems in member D are fed by a major distributary channel in the Waskahigan area. Channel fil l facies comprise basal sandstones exhibiting tidal cross-bedding overlain by thick, brackish marine mudstones. The channel is interpreted to have been filled as a microtidal estuary during the initial phase of transgression of member D.