The famous Twelve Apostles were younger than thought
Scientists have for the first time explained in detail how the Twelve Apostles formed in Australia and clarified their age. This is important because one of the country's most famous natural symbols is younger than previously thought.
The study showed that the history of the Twelve Apostles did not start with sea erosion alone. According to geologists, the rocks on this stretch of coastline were first uplifted and tilted due to the movement of tectonic plates. It was these processes that prepared the basis for the future rocks, and then the sea and wind began to carve out individual stone pillars from them.
To clarify the age of the rocks, the researchers studied microscopic marine fossils in the limestone. This allowed them to date the layers more precisely: they turned out to be about 8.6 to 14 million years old. Earlier estimates were wider - from 7 to 15 million years.
Details
At the same time, the pillars that tourists see today are much younger than the surrounding rocks. Scientists have come to the conclusion that the Twelve Apostles have acquired their present appearance only in the last few thousand years - after the end of the last ice age, when active coastal erosion exposed and shaped these rocks.
The authors also note that the cliffs near the Twelve Apostles still show tilted limestone layers and small faults - traces of ancient tectonic movements and earthquakes.
Why it's important
The study not only clarifies the history of one of Australia's most famous natural landmarks, but also helps us better understand the Earth's ancient climate. Scientists consider these rocks a kind of "time capsule": their layers preserve information about the marine environment and climate, including the period about 13.8 million years ago, when the planet was noticeably warmer than today.
It is also important from a practical point of view: the Twelve Apostles continue to be eroded by the sea. The researchers therefore emphasise that they should be studied now, while these natural structures are still in place.
Background
The Twelve Apostles are limestone sea pillars off the coast of Victoria, Australia. Today, there are fewer of them left than their name suggests: some have already collapsed due to natural erosion. The new study is published in the Australian Journal of Earth Sciences.
Source
The study was conducted by scientists at the University of Melbourne, led by Stephen Gallagher. The results are published in the Australian Journal of Earth Sciences.