Among the most fascinating of all geological periods is the remarkable time at the end of the Precambrian age, long dominated by the very simplest forms of unicellular life, when multicellular creatures seemed to burgeon suddenly into existence. One of the late Stephen J. Gould’s most intriguing little books was an extended study of the paleontological discovery and exploitation of the Burgess shale formation in Western Canada, which contributed so much to our initial understanding of that great event.

Now, after a fifteen year study by the expert geologists of the International Commission on Stratigraphy (ICS) and further evaluation by the International Union of Geological Scientists (IUGS), a new period has been added to the official timescale of earth’s history to reflect that unique transitional phase: the Ediacaran Period.

The Ediacaran represents approximately 50 million years of the Neoproterozoic, beginning roughly 600 million ago and extending to about 542 million years ago. It began with the conclusion of the final ice age of the Cryogenian Period that has popularly been characterized as “Snowball Earth”, a time when massive glaciations covered most of the planet, from 850 million to 600 million years ago. It concludes with the advent of the Cambrian.

(BBC News)

–From the May 2004 Austin Review KB