Post by L Roebuck on Jul 25, 2006 6:54:07 GMT -5
Jenolan Caves 340 million years old
Tuesday Jul 25 16:37 AEST
NSW's Jenolan Caves have been named the world's oldest discovered open caves after new Australian cave-dating research found them to be 340 million years old.
Scientists from the CSIRO, the University of Sydney and the Australian Museum used clay-dating methods to test the limestone caves near the Blue Mountains that attract thousands of tourists each year.
The technique, which was developed by the CSIRO to help petroleum exploration companies find oil deposits, is a variation of conventional potassium-argon dating, which can calculate the age of minerals by measuring levels of decay caused by radioactive potassium.
Armstrong Osborne, a senior lecturer at the University of Sydney, said he has long suspected the caves were older than the previous estimate of 90 to 100 million years.
But he said he was surprised to find they dated back 340 million years.
"We've shown that these caves are hundreds of millions of years older than any reported date for an open cave anywhere in the world," Dr Osborne said.
"Even in geological terms, 340 million years is a very long time.
"To put it into context, the Blue Mountains began to form 100 million years ago; dinosaurs became extinct 65 million years ago, and Tasmania was joined to the mainland as recently as 10,000 years ago."
The study is published in the latest issue of the Australian Journal of Earth Sciences.
Article: news.ninemsn.com.au/article.aspx?id=117074
Tuesday Jul 25 16:37 AEST
NSW's Jenolan Caves have been named the world's oldest discovered open caves after new Australian cave-dating research found them to be 340 million years old.
Scientists from the CSIRO, the University of Sydney and the Australian Museum used clay-dating methods to test the limestone caves near the Blue Mountains that attract thousands of tourists each year.
The technique, which was developed by the CSIRO to help petroleum exploration companies find oil deposits, is a variation of conventional potassium-argon dating, which can calculate the age of minerals by measuring levels of decay caused by radioactive potassium.
Armstrong Osborne, a senior lecturer at the University of Sydney, said he has long suspected the caves were older than the previous estimate of 90 to 100 million years.
But he said he was surprised to find they dated back 340 million years.
"We've shown that these caves are hundreds of millions of years older than any reported date for an open cave anywhere in the world," Dr Osborne said.
"Even in geological terms, 340 million years is a very long time.
"To put it into context, the Blue Mountains began to form 100 million years ago; dinosaurs became extinct 65 million years ago, and Tasmania was joined to the mainland as recently as 10,000 years ago."
The study is published in the latest issue of the Australian Journal of Earth Sciences.
Article: news.ninemsn.com.au/article.aspx?id=117074