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A review of Maastrichtian ammonite ranges

By
Peter D. Ward
Peter D. Ward
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Published:
January 01, 1990

Although Maastrichtian ammonite diversity was lower than that of the Campanian Age, the purported long-term diversity reduction of ammonites near the end of the Cretaceous may be more a product of sea-level change than evidence of a long-term slide toward extinction in this group. Examination of four geographic regions with exposed Cretaceous/Tertiary boundaries shows the presence of at least 22 species of ammonites within several meters or less of the K/T boundary. The exact level of ammonite extinction, however, cannot yet be determined; in no section can ammonites be demonstrated to disappear synchronously with the rapid extinction of planktonic foraminiferans and coccoliths occurring at the end of the Cretaceous.

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GSA Special Papers

Global Catastrophes in Earth History; An Interdisciplinary Conference on Impacts, Volcanism, and Mass Mortality

Virgil L. Sharpton
Virgil L. Sharpton
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Peter D. Ward
Peter D. Ward
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Geological Society of America
Volume
247
ISBN print:
9780813722474
Publication date:
January 01, 1990

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