Sudden and Gradual Molluscan Extinctions in the Latest Cretaceous of Western European Tethys
Incompleteness of the fossil record has confounded attempts to establish the role of the end-Cretaceous bolide impact in the Late Cretaceous mass extinctions. Statistical analysis of latest Cretaceous outer-shelf macrofossils from western European Tethys reveals (i) a major extinction at or near the Cretaceous-Tertiary (K-T) boundary, probably caused by the impact, (ii) either a faunal abundance change or an extinction of up to nine ammonite species associated with a regression event shortly before the boundary, (iii) gradual extinction of most inoceramid bivalves well before the K-T boundary, and (iv) background extinction of approximately six ammonites throughout the latest Cretaceous.
C. R. Marshall, Department of Earth and Space Sciences, Molecular Biology Institute, and Institute for Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095-1567, USA. P. D. Ward, Department of Geological Sciences, AJ-20, University of Washington, Seattle, WA 98195, USA.
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Marshall
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Ward