Home Page Science Frontiers

No. 60: Nov-Dec 1988

Issue Contents

Other pages

Other Interesting Sites











Global fire at the k-t boundary

The worldwide deposit of iridium at the K-T (Cretaceous-Tertiary) boundary has been considered very strong evidence that a large astronomical object (asteroid or comet) devastated our planet some 65 million years ago. Some scientists, however, propose that the iridium layer was instead deposited through widespread volcanic activity. The proponents of an astronomical mechanism should be heartened by a recent paper in Nature, by W.S. Wolbach et al. Here is their Abstract:

"Cretaceous-Tertiary (K-T) boundary clays from five sites in Europe and New Zealand are 102 -104 -fold enriched in elemental C (mainly soot), which is isotopically uniform and apparently comes from a single global fire. The soot layer coincides with the Ir layer, suggesting that the fire was triggered by meteorite impact and began before the ejecta had settled."

The composition of the hydrocarbons in the sediments points to the earth's biomass (mainly surface vegetation) as the source of the soot. The total quantity of K-T soot is equivalent to that which would be produced by burning 10% of all present terrestrial plant material.

(Wolbach, Wendy S., et al; "Global Fire at the Cretaceous-Tertiary Boundary," Nature, 334:665, 1988.)

Comment. Unmentioned in the above article is the possibility that extensive wildfires might have been generated by volcanic eruptions, perhaps accompanied by great electrical storms. The 1988 fires in Yellowstone needed no meteoric impact.

Reference. Chemical anomalies in the earth's crust are cataloged in ESC1 in Anomalies in Geology. To order this catalog volume, visit: here.

Concentration 'spikes' of iridium, carbon and soot at the KT boundary Concentration "spikes" of iridium, elemental carbon and soot at the KT boundary, Woodside Creek, New Zealand. (Adapated from Nature, 334:665, 1988).

From Science Frontiers #60, NOV-DEC 1988. 1988-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:


  • "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