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Uranium helps date Mass Extinction in Australia

April 14, 2005

Ian Metcalfe118.jpgInternational pioneers in geological dating are working with academics from the University of New England to determine precisely when the world’s biggest mass extinction happened.
Their findings could force a rethink among academics about whether Australia bore the initial brunt of such an extinction, commonly known as “the mother of all extinctions” and which occurred more than 250 million years ago.
Professor Ian Metcalfe, deputy director of the UNE Asia Centre, is leading a million-dollar, international research team investigating the Permian-Triassic Mass Extinction, which was probably caused by thousands of volcanoes erupting and which eventually led to the extinction of 98 per cent of the Earth’s species.
It is an extinction which has intrigued scientists worldwide, particularly Australian scientists, whose research in the late 1990s led them to believe the extinction happened later on land in Australia, compared to the extinction in the sea in the northern hemisphere.
But Professor Metcalfe (pictured) is calling this theory into question and has secured the professional assistance of world authorities.
Dr Roland Mundil, from the Berkeley Geochronology Centre in the US and Professor Robert Creaser, from the University of Alberta, Canada, are pioneers in using cutting-edge, Uranium-lead and Rhenium-Osmium isotopic techniques to date volcanic and sedimentary rocks.

The academics have been using their technology with Professor Metcalfe to date volcanic rocks in Queensland, home to some of the richest deposits of volcanic ashes containing zircons and other minerals critical in dating the age of the Earth.
Said Professor Metcalfe: “It is hoped this work will reveal if the mass extinction occurred at the same time in the sea and on land or at different times.
“This will provide vital constraints for suggested causes for this near annihilation of life on Earth.”
Professor Metcalfe’s work was published in the prestigious Science journal late last year.
“The most significant part of the research is developing a technique for pre-treating mineral specimens from millions of years ago which allows a more accurate dating using uranium-lead and the new exciting Rhenium-Osmium dating technique for dating sedimentary rocks,” Professor Metcalfe said.
He believes that has been achieved and with the help of Dr Mundil and Professor Creaser that results will soon reveal, once and for all, the exact time the Mother of all Extinctions happened in Australia and whether it happened first in the sea or on land.
For more information phone Professor Ian Metcalfe on 6773 3499 or Lydia Roberts on 6773 2779.

Posted by Lydia Roberts at April 14, 2005 01:22 PM