Published on Brock University (http://www.brocku.ca)
Sept. 23, 2009
A Brock University Earth Sciences professor is part of a team of scientists who have rewritten the geological timescale that measures time in terms of geology — from the formation of the Earth to present day.
In a paper published today in the September issue of the Journal of Quaternary Sciences, Professor Martin Head and his colleagues affirm the official extension of the beginning of the Quaternary Period — the interval of geological time in which humans evolved and now live — downwards from 1.8 to 2.6 million years (Ma).
The Neogene Period, which immediately precedes the Quaternary, has therefore been truncated.
“The reclassification of this geological timescale boundary repositions the period in which our human ancestors evolved to a time of significant climatic and environmental change,” says Head. “This new Quaternary base makes sense geologically and also makes it easier to identify this important boundary around the world.
“The significance of this announcement is on par with the downgrading of Pluto from a planet to a dwarf planet in 2006. It also illustrates the importance of science, discovery and synthesis in making sense of the world and our part in it. As a result of this change, all geology textbooks will now need to be rewritten.”
In June 2009, the Executive Committee of the International Union of Geological Sciences (IUGS), which presides over the geological timescale, formally ratified a proposal by the International Commission on Stratigraphy to lower the base of the Quaternary System/Period.
The geological timescale in its modern form emerged during the 19th century. The term “Quaternary” is a quaint reminder of an earlier and now outdated view that geological time could be subdivided into four units.
The Journal of Quaternary Sciences article, “Formal ratification of the Quaternary System/Period and the Pleistocene Series/Epoch with a base at 2.58 Ma” is available online: www3.interscience.wiley.com/journal/122602421/abstract