Over 445mn years old Earth climate recreated
By ANITuesday, August 10, 2010
WASHINGTON - Geologists have recreated Earth’s climate belts that existed between 460 and 445 million years ago.
An international team of scientists including Mark Williams and Jan Zalasiewicz of the Geology Department of the University of Leicester, and led by Dr. Thijs Vandenbroucke conducted this study.
The team of scientists looked at the global distribution of common, but mysterious fossils called chitinozoans - probably the egg cases of extinct planktonic animals - before and during this Ordovician glaciation.
They found a pattern that revealed the position of ancient climate belts.
The position of these climate belts changed as the Earth entered the Ordovician glaciation - but in a pattern very similar to that which happened in oceans much more recently, as they adjusted to the glacial and interglacial phases of our current (and ongoing) Ice Age.
The pattern suggests that carbon dioxide levels were about five times that of current levels.
“These ancient, but modern-looking oceans emphasise the stability of Earth’s atmosphere and climate through deep time - and show the current man-made rise in greenhouse gas levels to be an even more striking phenomenon than was thought,” concluded the researchers.
The findings have been published online in the Proceedings of the National Academy of Sciences of the USA. (ANI)
