The Nullarbor Plain in southern Australia used to be a huge ocean. It's a scrubby desert on limestone bedrock that extends for over a thousand kilometers.
A new discovery suggests that the expanse may not be as featureless as we were led to believe.
An international team of scientists has found an ancient landform that appears to have once been a coral reef.
Limestone can be formed from calcium carbonate from shells and fossils, but there are no primary features associated with the deposition of carbonate.
It could be the first primary depositional structure ever found on the plain, as the landform consists of a circular elevated ring about 1,300 meters wide with a dome in the center.
If you have the right tools, you can investigate the history of the Nullarbor Plain, which has remained largely unchanged by weathering and erosion over millions of years.
The first of its kind, the clear remnant of an original sea-bed structure, has been identified by high-resolution satellite imagery and field work.
The ring-shaped 'hill' can't be explained by extra-terrestrial impact or any known processes, but it can be explained by the original features of the Great Barrier Reef.
The majority of Australia is now arid and dry. The continents were teeming with life millions of years ago, not just dense forests, but huge inland seas as well.
The shallow-water limestones that were deposited during the middle Cenozoic were exposed when the ocean dried up.
There has been very little happening on the plain since that time. There have been no major upheavals that led to the formation of mountain ranges or other features.
A clean record of geological processes and features can be found in the Nullarbor.
The channels of long-vanished rivers, as well as sand dune systems imprinted directly into limestone, preserve an archive of ancient landscapes.
It's not limited to landscapes. The mummified remains of Tasmanian tigers and complete skeletons of long- extinct animals can be found in the Nullarbor Plain preserve.
There is more to that. The Nullarbor Plain has preserved large quantities of meteorites, allowing us to peer back through time to the beginnings of our Solar System.
Scientists have only recently been able to discover some of the plain's more subtle features, including the reef-like structure.
The benthic foraminifera are single-celled marine organisms. It is consistent with the limestone found in the area.
One of the samples showed that the stone was bound by coral or algae when it was formed.
The organisms that are capable of laying down organic material are the only ones that have been found in the limestone. It is believed that the structure is the result of limestone being deposited.
"These features, along with the millions of years old landscape feature we have now identified, make the Nullarbor Plain a land that time forgot and allow a fascinating deeper understanding of Earth's history," Barham said.
The research has been published in a journal.
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