Scientist have just extended the range of Australia’s iconic Twelve Apostles. In a recent discovery, University of Melbourne PhD student Rhiannon Bezore discovered five interesting limestone stacks 50 meters (165 feet) under water.
Rhiannon在分析声纳数据时发现了“溺水”的石灰石堆栈,这是她的博士学位项目,以调查沿海地区潜在的礁石栖息地。新的溺水芦笋坐落在维多利亚州南部海岸十二使徒的陆上淹没的古沿海悬崖前。
“We are calling them the Drowned Apostles because if you had stood on this ancient cliff face over 20,000 years ago they would have looked largely the same as the current Twelve Apostles,” says University of Melbourne coastal geographer David Kennedy, who is supervising Ms Bezore’s PhD work.
Normally these type of limestone structure should be completely eroded, however Professor Kennedy suggests they could have been submerged by rising sea levels. According to Associate Professor Kennedy, the most likely explanation is that at the end of the last ice age, around 20,000 years ago sea levels rose so fast as the ice melted that the stacks were simply swamped in place.
“Sea levels probably rose at the end of the last ice age so quickly that the sea just ran across the top of these things without knocking them over,” says Associate Professor Kennedy, from the School of Geography. “It is amazing that they survived.”
The research has been published in the US-basedJournal of Coastal Researchand presented at the国际沿海研讨会at Coogee in Sydney.
Following the The limestone cliffs being eroded by crashing waves we can see how the Drowned Apostles fall in line with their 12 cousins. The ”drowned” stacks are made of the same eroded limestone as the seaside Twelve Apostles
“As the drowned Apostles are found in the same geological setting as the current Twelve Apostles, it is reasonable to assume that they were formed under the same geomorphic processes, some 60,000 years apart,” the researchers say in the journal article.
Through erosion the height of the Drown Apostles was warn down below the height of the Tweleve Apostled, suggesting that the sunken stacks had stood for much longer under eroding conditions before they were submerged still intact. They now stand up to nearly 7m tall compared to the Twelve Apostles that range from 30m to 67m tall.
[University of Melbourn]