Sudden extinction of the dinosaurs: Latest cretaceous, upper great plains, U.S.A.
Date of Original Version
Results of a three-year field study of family-level patterns of ecological diversity of dinosaurs in the Hell Creek Formation of Montana and North Dakota show no evidence (probability P < 0.05) of a gradual decline of dinosaurs at the end of the Cretaceous. Stratigraphic reliability was maintained through a tripartite division of the Hell Creek, and preservational biases were corrected for by comparison of results only from similar facies as well as through the use of large-scale, statistically rigorous survey and collection procedures. The findings are in agreement with an abrupt extinction event such as one caused by an asteroid impact.
Publication Title, e.g., Journal
Sheehan, Peter M., David E. Fastovsky, Raymond G. Hoffmann, Claudia B. Bergbaus, and Diane L. Gabriel. "Sudden extinction of the dinosaurs: Latest cretaceous, upper great plains, U.S.A.." Science 254, 5033 (1991). doi: 10.1126/science.11536489.