Just a few years ago, many scientists, especially physicists and astronomers, considered the Book of Science to be closed in the matter of what happened at the Cretaceous-Tertiary (K-T)
boundary, 65 million years ago, and why the dinosaurs met their end. It was declared, rather imperiously, that a large asteroid had impacted the earth, causing much physical and biological devastation. Many scientific papers are still being written on this singular period in the earth's history, and the situation is no longer so clear-cut. We select for brief review four papers, each with a different perspective.
Occurrence of stishovite. Stishovite, a dense phase of silica, is widely accepted as an indicator of terrestrial impact events. It is not found at volcanic sites. Now, J.F. McHone et al report its existence at the K-T boundary, at Raton, New Mexico.
(McHone, John F., et al; "Stishovite at the CretaceousTertiary Boundary, Raton, New Mexico," Science, 243:1182, 1989.) A plus for the pro-impact side.
The impact of an asteroid can initiate basaltic flooding and trap formation.
Evidence of a global fire. Soot appears at the K-T boundary at many sites, but where did it come from? Chemical analyses of these soots show an enhanced concentration of polycyclic aromatic hydrocarbons over soots above and below the boundary. This is strong evidence of pyrolytic action at the K-T boundary; i.e., widespread fires.
(Venkatesan, M.I., and Dahl, J.; "Organic Geochemical Evidence for Global Fires at the Cretaceous/Tertiary Boun dary," Nature, March 2, 1989.) Fire could have been initiated by either volcanism or impacts.
The evidence of the traps. Traps, like India's famous Deccan Traps, are extensive flood basalts. In this paper, basalt flooding has been correlated with mass extinctions of marine life during the past 250 million years. The Deccan Traps were formed right at the K-T boundary. Traps could, however, be initiated by asteroid impact, which could stimulate eruptions.
(Rampino, Michael; "Dinosaurs, Comets and Volcanoes," New Scientist, p. 54, February 18, 1989.)
The dinosaur angle. If dinosaurs were truly susceptible to extinction by either asteroid impact, widespread volcanism, or some combination of both, one would expect to find their numbers and diversity drastically curtailed during Mesozoic impact events. Instead, the dinosaurs not only survived these impacts but prospered. Their demise, which began before the K-T event, was probably not due to either impact or vol canism.
(Paul, Gregory S.; "Giant Meteor Impacts and Great Eruptions: Dinosaur Killers?" BioScience, 39:162, 1989.)
Reference. Impact craters and stratigraphic evidence of catastrophism are cataloged in: Carolina Bays, Mima
Mounds and Anomalies in Geology, respectively. For information on these catalogs, visit: here.
"A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980
"An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
"..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983
"Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987
