An Incised Valley in the Cardium Formation at Ricinus, Alberta: Reinterpretation as an Estuary Fill

The Ricinus incised valley (Turonian–Coniacian Cardium Formation) is at least 50 km long, 10 km wide and up to about 30 m deep. It trends NW–SE, parallel to tectonic trends and shoreline trends in the Cardium Formation. It cuts into shallow‐marine mudstones and sandstones (Raven River Allomember of the Cardium), and is truncated by a transgressive surface of erosion (E5). The valley fill forms a small oil reservoir in the subsurface, but the …