Researchers at the University of Melbourne have explained how Australia's famous Twelve Apostles rose from the sea. Their findings show that movements of tectonic plates, the huge pieces of Earth's outer layer, gradually lifted and tilted these massive rock formations over millions of years.
Until now, scientists had only a limited understanding of how the Twelve Apostles developed into the landmark seen today.
Stephen Gallagher, who led the study at the University of Melbourne, said these movements turned the Apostles into one of the most complete and accessible records of past environmental conditions.
"Much like an environmental time capsule, each layer of these giant structures preserved information about the Earth's climate, tectonic activity, plants, and animals over millions of years," Gallagher explained. This includes a time about 13.8 million years ago when the climate was much warmer than it is today.
He added, "We are using this 'window back in time' to understand where temperatures and sea levels may be heading on our current path of climate change."
The rock layers, similar to tree rings, have allowed scientists to estimate the age of the limestone more precisely. Earlier research had estimated these layers to be between seven and fifteen million years old. However, tiny fossils dated them more accurately to between 8.6 and 14 million years old.
The study was published in the Australian Journal of Earth Sciences.
The research shows that while movements of Earth's plates slowly pushed the rock layers upward over millions of years, the dramatic pillars visible today formed much more recently. After the last Ice Age, rising seas and coastal erosion carved and exposed the towering structures along the shoreline.
The team also found that the layers did not rise evenly. Instead, they bent and broke during the process. Today, visitors can see that the limestone layers in the surrounding cliffs are tilted by a few degrees rather than lying flat.
Scientists are now studying individual layers in greater detail to learn about past climates, ocean conditions, and sea levels. This work could help explain how ancient geological processes continue to shape modern coastlines and influence ongoing erosion.