Willow Creek Formation

The Willow Creek Formation is a stratigraphic unit in southwestern Alberta, extending slightly into northern Montana, that preserves an important record across the Cretaceous-Paleogene boundary. First described in 1883 and later formally defined in 1930, it includes lower Late Cretaceous and upper Early Paleocene rocks that capture the transition from the final age of non-avian dinosaurs into the earliest Paleocene. Its non-marine shales, red beds, and sandstones were deposited by rivers and floodplains under arid to semi-arid conditions. Dinosaur fossils, including Tyrannosaurus rex, and abundant eggshell fragments make it a significant source for understanding shifting environments, climates, and animal life.

Alberta · Canada