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Meteorites and dinosaurs
I'm sure the message about the hypothetical Yucatan impact will
produce a flood of responses. I wish to make only two points:
1. It is by no means a fact that the Chicxulub structure -is-
an astrobleme. Meyerhoff, et al., in January 1994 _GEOLOGY_,
p. 3-4, argue and present some impressive data that the structure
is volcanic and -contains- Late Cretaceous deposits within. If it
originated from an end-Cretaceous impacts it could not contain
te data to argue either way about
the population dynamics of latest Cretaceous dinosaur life.
Williams, 1994, _JOURNAL OF PALEONTOLOGY_, V. 68(2), p. 183-190
makes this point clear and counterargues studies suggesting that
penultimate Cretaceous dinosaurs were abundant and diverse. My
point is that no model is robust at this point.
3. Factual error: many large animals survived the K/T impact,
including Crocodilians such as _Thoracosaurus_ and _Leidyosuchus_,
and many turtles well ove 20kg.>[D>[D>[D>[D>[D>[D>[D>[Dr>[over 20kg. Our lack
nearshore marine deposits probably biases our view of this biota.
I'm sure others have views on this. Enjoy the discussion.
David Schwimmer, Columbus College, Columbus GA