One of the richest fossil records of ancient Australian life has been added to a prestigious international geological heritage list, recognising decades of discovery led by UNSW scientists.
A Queensland fossil site which transformed our understanding of Australia's prehistoric past has been recognised among the world's most important geological sites.
The Riversleigh World Heritage Area in north-west Queensland has been named an International Union of Geological Sciences (IUGS) Geological Heritage Site, for its outstanding scientific value and the role it has played in helping scientists understand the earth's history.
The recognition follows more than four decades of fossil discoveries at Riversleigh led by UNSW Sydney researchers and collaborators, cementing the site as one of the world's most significant records of ancient life.
Ancestors of the Tasmanian tiger , marsupial sloths and tree-climbing crocodiles are among the thousands of fossils found at the site on Waanyi country in Boodjamulla National Park. Encased in hard freshwater limestone, the fossils span 25 million years of evolution and offer rich insights into how Australia's fauna and flora responded to dramatic prehistoric environmental changes.
"What makes Riversleigh extraordinary is that it's not just fossils from one point in time," said UNSW palaeontologist Professor Mike Archer, from the School of Biological, Earth & Environmental Sciences (BEES).
"It has layer upon layer of fossil deposits all stacked on top of one another. It's like a huge book of rocks, with each layer representing a different page in time. It's an enormously important geological site that gives us an unparalleled record of how Australia's animals and environments have changed over millions of years to become what we have today."
Prof. Archer, a former UNSW Science Dean, pioneered exploration of the site from the late 1970s, alongside Professor Suzanne Hand and Mr Henk Godthelp, also from the School of BEES. Since then, more than 100 experts from 44 institutions across 10 countries have been involved in Riversleigh research.
"Riversleigh is an amazing site," Prof. Hand said. "It documents a period of dramatic transformation and has revealed how Australia's unique wildlife evolved during cycles of natural climate change that transformed the continent's vast, ancient rainforests into the open forests, woodlands and grasslands of today."
Riversleigh is one of 100 new sites from 47 countries recognised by the Union as part of The Third 100 IUGS Geological Heritage Sites list, announced at the IUGS Geoheritage Event in Portugal on Friday. The Bungle Bungles in Western Australia, K'gari (Fraser Island) in Queensland and the Dundas Mineral Field in Tasmania also made the list.
They join the ranks of 200 existing Geological Heritage Sites - including Uluru, The Grand Canyon, Mount Everest and Mount Kilimanjaro - announced in recent years. More than 1000 experts have contributed to the programme by proposing sites, participating in the selection process and evaluating their scientific quality.
UNSW Science Dean, Scientia Professor Sven Rogge, said Riversleigh's inclusion in the Third 100 list reflected its global significance.
"Riversleigh is one of the world's most significant fossil and geological sites, revealing how Australia's biodiversity and environments have changed over millions of years," Prof. Rogge said.
"This recognition reflects the site's scientific importance and the dedication of the researchers, students and collaborators who have studied it over many decades. Their discoveries have deepened our understanding of Australia's ancient past and offer lessons for our future as we adapt to a changing climate."
It's an enormously important geological site that gives us an unparalleled record of how Australia's animals and environments have changed over millions of years to become what we have today.
A record written in stone
The latest honour builds on Riversleigh's longstanding significance. In 1994, it was added to UNESCO's World Heritage List as part of the Australian Fossil Mammal Sites World Heritage Area, alongside South Australia's Naracoorte Caves.
Described by Sir David Attenborough as ' one of the four most important fossil deposits in the world ', Riversleigh covers more than 100 square kilometres and contains thousands of fossil deposits. More than 200 new animal and plant species have been discovered there with more being discovered every year.
Research is conducted in partnership with the Waanyi people, the traditional owners and custodians of the land. Some new fossil species have been named using the Waanyi language, while collaborative programs are helping connect fossil discoveries with living animals and the region's cultural heritage.
While fossils typically get all the limelight, it's the limestone that makes the incredible discoveries possible, said Prof. Hand.
"The site has preserved biological detail that is rarely seen in the fossil record. It's not just bones and teeth, there are plants, organs, soft tissues, individual cells and even perfect, uncrushed 17-million-year-old nuclei preserved in those cells. Together they provide an extraordinary picture of ancient ecosystems and how they functioned," she said.
Radiometric dating of the site's fossil-bearing rock helped establish one of Australia's most important dated fossil sequences, allowing researchers to estimate the age of other fossils around the country by comparing them with those preserved at Riversleigh.
"People often focus on the fossils, but geology and palaeontology are inseparable," Prof. Archer said. "Without the rocks of Riversleigh, we wouldn't have the preserved fossils, as detailed a picture of ancient ecosystems or insight into the geological conditions that enable such incredible preservation."
UNSW Emeritus Professor David Cohen, a former Head of BEES and the Treasurer of the IUGS described Riversleigh as an "Aladdin's cave of fossil materials" and "one of the most important vertebrate fossil localities on the planet".
Prof. Cohen, who was not on the expert panel that selected the site, said: "Riversleigh is recognised within the geoscientific community as one of the most important vertebrate fossil localities on the planet. Inclusion in the Third 100 list will help spread this fame to the broader community."
By recognising sites of geological significance and supporting the creation of more geoparks and geotrails, the IUGS aims to raise awareness of the geosciences and inspire the future generations of researchers needed to tackle environmental and resource challenges, Prof. Cohen said.
Lessons from the past for the future
Despite more than four decades of discoveries, researchers believe Riversleigh still has more stories to tell. More recent work has expanded beyond the existing World Heritage Area, with newly identified fossil deposits helping fill gaps in Australia's evolutionary record.
Beyond revealing Australia's prehistoric past, Riversleigh is also helping researchers understand how ecosystems respond to climate change, with the fossil record capturing periods of a warming and cooling climate.
"We don't have to guess what climate change is going to do to Australian flora and fauna, because we've seen it happen before," Prof. Archer said. "The fossil record is such a powerful tool for understanding how animals and ecosystems responded to those changes. We can use it to develop conservation strategies to help better protect ecosystems from the risks that lie ahead."
Prof. Archer and Prof. Hand hope the international recognition will help generate support for further research into the palaeontological and geological treasures of Riversleigh, noting UNSW researchers are desperately seeking funding to be able to continue to process the limestones that have already been collected.
"We know the answers to questions about the impacts of current climate change are waiting to be discovered in those blocks of limestone. There's still so much more to learn about the relations between the past, present and the future," Prof. Archer said.
"The international recognition shines a light on the value of this work and the importance of continuing to explore, understand and protect what's been preserved at Riversleigh."
