The Geological Society of America (GSA) released its new Geological Time Scale April 9, 2009. Overnight, the Pleistocene Epoch is much older, by definition!
This is GSA's first full time scale revision in 25 years. The new revision did not await final resolution and international consensus. Debate continues among researches within the International Commission on Statigraphy, an international body meant to gain international time scale uniformity. The GSA chart anticipates changes likely to come as this debate settles.
According to GSA...
"Some aspects of the GSA Geologic Time Scale do not conform to the recommendations of the International Commission on Stratigraphy. The names “Tertiary” and “Pre-cambrian” were not dropped on the new time scale. The Quaternary, the status and boundaries of which are still being debated, was modified to reflect some of the pending recommendations. These differences were retained to best reflect the needs of GSA members and Divisions."
Principal among important changes; The Pleistocene Epoch now begins at 2.6 million years ago. That's 0.8 million years earlier than before. The start of the Pleistocene Epoch marks the time when significant climate cooling resulted in significant changes in the fossil record (among other changes).
Environmental History Timeline May 9, 2013
1 week ago