The quaternary starts now 800.00 years earlier
Long dispute over the beginning of the last great geological era decidedRead out
After decades of debate and four years of negotiations, an international body of geoscientists has finally formally agreed to move the beginning of Earth's last great age, the Quaternary, 800, 000 years forward. The new border now corresponds to a natural incision, the climate-cooling that took place 2.6 million years ago and thus the beginning of the ice age.
In the 18th century, geoscientists developed a first classification for the history of the earth, which divided them into four epochs: Primary, Secondary, Tertiary and Quaternary, so the names at that time. Later, the first two were renamed Paleozoic and Mesozoic, but the last two remained for 150 years the measure of all things for geologists. In 2004, the internationally binding division of the geological time scale was changed again by the International Commission on Stratigraphy (ICS). The Tertiary beginning with the mass extinction at the end of the Cretaceous was now divided into two periods, Paleogene and Neogene.
The Quaternary, however, was initially preserved in this reform. But even at this time or at the beginning of its time has been argued for decades. In 1983, the beginning was set to 1.8 million years before today, at the beginning of the Pleistocene. But, as many critics say, this point is purely arbitrary, do not commit itself to geological changes.
Gelasium now counted to Quaternary
Now, the International Commission on Stratigraphy has responded and has advanced the Quaternary by 800, 000 years to 2.6 million years ago today. Thus, it now also includes the previously included in the Pliocene Gelasium, an era that begins by a reversal of the terrestrial magnetic field and also heralds by a significant cooling down the beginning of the ice age. Overall, the new Quaternary thus includes the entire Ice Age and the Holocene, the advent of tool-using people.
New border corresponds to natural incision
"It has long been agreed that the Quaternary frontier should be at the first sign of global climate change, " explains Professor Philip Gibbard of Cambridge University in England. "Now we have made the definition of the Quaternary border an internationally recognized and fixed point that marks a natural event: the beginning of the ice age on a global scale." Display
"The decision is very important for the field-based scientific community, " said Chris Caseldine, one of the editors of the "Journal of Quaternary Science", who now publishes the official new reading has been. It provides us with a point in geological time when we moved into a climatic, ra that looks like today.
(Wiley - Blackwell, 23.09.2009 - NPO)