Sudden extinction of the dinosaurs: latest Cretaceous, upper Great Plains, USA

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Science  08 Nov 1991:
Vol. 254, Issue 5033, pp. 835-839
DOI: 10.1126/science.11536489


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 fades 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.

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