Abstract

Glaebular paleosol and pedogenic limestone in the Willow Creek Formation should be recognized as important features in paleoclimatic interpretations. A semiarid floodplain environment of the Willow Creek Formation in the southern Foothills can be contrasted with the poorly drained, swampy floodplain (Coalspur coal zone) of the central Foothills. Such an interpretation for the Willow Creek Formation, based on sedimentology, is supported palynologically by the exceptionally high number of low-yield samples, the low diversity of the Late Maastrichtian assemblages and the occurrence of Classopollis. The abundance of Concentricystes in many samples, which are otherwise nearly barren of palynomorphs, suggests a well drained soil as its ecological niche.

The correlation and paleoenvironmental comparison between the Willow Creek Formation and the Coalspur coal zone is now possible by the recognition of the Cretaceous-Tertiary boundary within the Willow Creek Formation. An age range of Early to Middle Paleocene is suggested for the Porcupine Hills Formation.