Gradual Dinosaur Extinction and Simultaneous Ungulate Radiation in the Hell Creek Formation

1986/05/02 by Robert E. Sloan, Jane R. Rigby, Leigh M. Van Valen +1 · 8 citations
Earth and Planetary Sciences · #Paleontology and Evolutionary Biology #Evolution and Paleontology Studies #Paleontology and Stratigraphy of Fossils

paper · doi:10.1126/science.232.4750.629

openalex publication_date 1986/05/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/23

Abstract

Dinosaur extinction in Montana, Alberta, and Wyoming was a gradual process that began 7 million years before the end of the Cretaceous and accelerated rapidly in the final 0.3 million years of the Cretaceous, during the interval of apparent competition from rapidly evolving immigrating ungulates. This interval involves rapid reduction in both diversity and population density of dinosaurs. The last dinosaurs known are from a channel that contains teeth of Mantuan mammals, seven species of dinosaurs, and Paleocene pollen. The top of this channel is 1.3 meters above the likely position of the iridium anomaly, the Cretaceous/Tertiary boundary.

Cited by

• Estimating the diversity of dinosaurs
• The extinction of the dinosaurs
• Ecological niche modelling does not support climatically-driven dinosaur diversity decline before the Cretaceous/Paleogene mass extinction
• Mass extinctions past and present: a unifying hypothesis
• Dinosaur diversity during the transition between the middle and late parts of the Late Cretaceous in eastern Shandong Province, China: Evidence from dinosaur eggshells
• Evidence of reworked Cretaceous fossils and their bearing on the existence of Tertiary dinosaurs
• Habitat preferences of the enigmatic Miocene tethythere Desmostylus and Paleoparadoxia (Desmostylia; Mammalia) inferred from the depositional depth of fossil occurrences in the Northwestern Pacific realm
• Dinosaur [wikipedia]