Imma Perfetto
Cosmos science journalist
From high above it looks almost like a bullseye stamped into the earth but according to Australian and Slovenian researchers this enigmatic structure discovered on the vast Nullarbor Plain in Australia is much, much, cooler.
Using advanced satellite imagery scientists have unearthed the preserved remains of a reef-like structure that would have one once been submerged on the sea floor of an ancient ocean.
According to the new report, published in the journal Earth Surface Processes and Landforms, the reef would have first formed when the Nullarbor Plain was underwater over 14 million years ago.
“Unlike many parts of the world, large areas of the Nullarbor Plain have remained largely unchanged by weathering and erosion over millions of years, making it a unique geological canvas recording ancient history in remarkable ways,” says co-author Dr Milo Barham, from the Timescales of Mineral Systems Group within the School of Earth and Planetary Sciences at Curtin University in Perth.
“Through high-resolution satellite imagery and fieldwork, we have identified the clear remnant of an original sea-bed structure preserved for millions of years, which is the first of this kind of landform discovered on the Nullarbor Plain,” Barham adds.
The reef structure isn’t small, with an outer diameter between 1200-1300 metres, and it consists of a circular elevated rim and a central dome.
“The ring-shaped ‘hill’ cannot be explained by extra-terrestrial impact or any known deformation processes but preserves original microbial textures and features typically found in the modern Great Barrier Reef,” explains Barham.
It’s discovery was made possible due to greater access to new high-resolution satellite imagery from the 0.4 arc-second TanDEM-X digital elevation model (DEM) by the German Aerospace Centre.
The Nullarbor Plain is largely treeless, the origin of its name actually comes from the Latin nullus arbor meaning “no trees”. This made it possible for DEM to create a precise 3D map of its surface to search for and find fine-scale landforms.
Located on the coast of the Great Australian Bight and bound, to the north by the Great Victoria Desert, the flat Nullarbor Plain spans 200,000 km2 across South Australia and Western Australia.
“Evidence of the channels of long-vanished rivers, as well as sand dune systems imprinted directly into limestone, preserve an archive of ancient landscapes and even a record of the prevailing winds,” says Barham.
“And it is not only landscapes. Isolated cave shafts punctuating the Nullarbor Plain preserve mummified remains of Tasmanian tigers and complete skeletons of long-extinct wonders such as Thylacoleo, the marsupial lion. At the surface, due to the relatively stable conditions, the Nullarbor Plain has preserved large quantities of meteorites, allowing us to peer back through time to the origins of our solar system,” he adds.
“These features, in conjunction with the millions of years old landscape feature we have now identified, effectively make the Nullarbor Plain a land that time forgot and allow a fascinating deeper understanding of Earth’s history.”
