ABSTRACT: Dragged toward Armageddon: A Changing Paleontological Viewpoint on Catastrophism

HICKEY, LEO J., Yale University, New Haven, CT

The epic discovery of an iridium anomaly at the Cretaceous-Tertiary boundary caused a fundamental change in geologists' attitude toward catastrophist hypotheses. Paleontologists, however, have been noticeably reluctant to accept the new paradigm, possibly because of history and the nature of their materials. Much of the early development of paleontology involved the gradual growth, from an incomplete and episodic fossil record, of the inference of the essential continuity of life as against the views of catastrophists, creationists, or extreme saltationialists. Eventually paleontology became one of the principal bulwarks of the Neo-Darwinian Synthesis with its view of the gradual accumulation of change through natural selection operating in a uniformitarian world.

Other limitations arise from the nature of fossils themselves, the complex and often unpredictable ways in which organisms respond to the application of stress, and the difficulty of securing numerous, closely spaced samples from a large number of isochronous localities in order to resolve short-term events. However, no matter how abundant and closely spaced the samples, some degree of gradualness in the pattern of extinction will always remain. Nevertheless, where the record of groups that provide high-resolution assemblages, including pollen and marine microfossils, has been carefully studied, the K/T boundary now appears to show clear paleontological evidence of a major extinction event of short duration that led to collapse of major trophic levels and fundamental reorganization of succeeding communities. This has introduced an important element of chance into the evolutionary explanation for the present diversity and makeup of life.

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)