Abstract

Over the years there have been numerous efforts to reconstruct paleobathymetry for the Cretaceous Western Interior Seaway. Different methods have resulted in widely variable estimates of maximum depth, however, and few, if any studies have attempted basinwide reconstructions. Recently the development of numerical models to describe the 3-dimensional dynamics of circulation in the basin have necessitated the construction of paleogeographic/paleobathymetric maps for the Western Interior. This report describes the development of an Early Turonian paleogeographic/paleobathymetric map based on a review of current literature. The map is presently being employed in the initial simulations of a Western Interior numerical circulation model. Determination of paleobathymetry is based primarily on the relationship between depositional environments/lithofacies and depth observed in modern marine settings, and is supported by faunal data. Three maps are presented, including the locations of sections containing Early Turonian marine strata and inferred paleoshorelines, Early Turonian lithofacies, and Early Turonian paleobathymetry. Features of the paleobathymetric reconstruction that have a critical effect on circulation in preliminary model simulations are discussed.