The upper cretaceous Horseshoe Canyon formation: using palesols to reconstruct ancient environments, climates, and record of sea level change in a dinosaur-dominated terrestrial ecosystem

Abstract

Paleosols are investigated to reconstruct Late Cretaceous paleoenvironments and paleoclimates of the Horseshoe Canyon Formation. Based on hydrology, degree of development, and pedogenic features, paleosols record the transition from wetland environments to well-drained environments and back to poorly-drained environments through the formation. Paleoclimatic reconstructions indicate that the lower half of the formation was warm and humid, but a period of cooling and drying occurred in the middle of the formation. A complex relationship exists between paleoenvironmental and paleoclimatic changes and a terrestrial vertebrate faunal turnover within the Horseshoe Canyon Formation. The distribution of paleosols was also compared to sequence stratigraphic interpretations of the HCFm to determine if paleosols recorded evidence of base level changes. Although HCFm paleosols do record some marine transgressive-regressive cycles, the ability to resolve these cycles depends on the distance to the shoreline and the magnitude of the sea­level change.