edited byJennifer Sills
Cretaceous Extinctions: Multiple Causes
IN THE REVIEW "THE CHICXULUB ASTEROID IMPACT AND MASS EXTINCTION ATTHE CRETACEOUS-
Paleogene boundary" (P. Schulte et al., 5 March, p. 1214), the tenninal Cretaceous extinctions
were confidently attributed to a single event, the environmental consequences of the impact
ofan extraterrestrial body. The list of41 authors, although suggesting a consensus, conspicu-
ously lacked the names ofresearchers in the fields ofterrestrial vertebrates, including dino-
saurs, as well as freshwater vertebrates and invertebrates. Although we the undersigned differ
over the specifics, we have little doubt that an impact played some role in these extinctions.
Nevertheless, the simplistic extinction scenario presented in the Review has not stood up to
Deccan plateau basalts. Lava from Deccan
volcanism formed distinct layering.
the countless studies of how vertebrates and
other terrestrial and marine organisms fared
at the end ofthe Cretaceous (1-4).
Patterns of extinction and survival were
varied, pointing to multiple causes at this
time-including impact, marine regression,
volcanic activity, and changes in global and