|List||World Heritage List|
|Legal Status||Declared property (17/12/1994)|
|Place File No||4/07/287/0002|
|Statement of Significance|
Over 2000 kilometres separate the two sites which form
the World Heritage property. Riversleigh (10 000 hectares), located in north
western Queensland, is confined to the watershed of the Gregory River. The site
at Naracoorte, South Australia, covers 300 hectares and is located in flat
country, punctuated by a series of stranded coastal dune ridges that run
parallel to the present coastline.
Riversleigh is one of the world's richest Oligo-Miocene mammal records, linking that period (15-25 million years ago) to the predominantly modern assemblages of the Pliocene and Pleistocene epochs. The site provides exceptional examples of middle to late Tertiary mammal assemblages, in a continent whose mammalian evolutionary history has been the most isolated and most distinctive in the world.
The extensive fossil deposits at Riversleigh are encased in hard, rough limestone, which was formed in lime-rich freshwater pools. They span a record of mammal evolution of at least 20 million years in length, providing the first records for many distinctive groups of living mammals, such as marsupial moles and feather-tailed possums, as well as many other unique and now extinct Australian mammals such as 'marsupial lions'.
The variety of deposits at Riversleigh has led to an understanding of how the environment has changed over time from a rich rainforest community to semi-arid grassland, and how the animals that lived in it have changed too.
The discovery of the fossils at Riversleigh has profoundly altered the understanding of Australia's mid-Cainozoic vertebrate diversity. The remains of a 15 million-year-old monotreme has provided new information about this highly distinctive group of mammals, and several Tertiary thylacines have been identified. Placental mammals are represented by more than 35 bat species and the Riversleigh fossil bat record is the richest in the world.
In stark contrast to the semi-arid conditions at Riversleigh stand the cool caves at Naracoorte. Here are fossils that document a distinctive fauna, with the ancestors of modern species alongside the doomed giants of a world that was about to be devastated by climatic changes.
The fossils in the Naracoorte Caves illustrate faunal change spanning several ice ages, highlighting the impacts of both climatic change and humankind on Australia's mammals from at least 350 000 years before the present.
Further research at the Naracoorte Caves sites is expected to document a series of snapshots of Pleistocene life in south east Australia, including details of climate and vegetation associated with the fauna. Recent geological research suggests that deposits of Pliocene and even Miocene age could be found at the site, thus providing closer links with the site at Riversleigh.
Specimens representing 99 vertebrate species have been discovered, ranging in size from very small frogs to buffalo-sized marsupials. These include exceptionally preserved examples of the Australian Ice Age megafauna, as well as a host of modern species such as the Tasmanian devil, thylacine and others. The Naracoorte fossils span the probable time of the arrival of humans in Australia, and this is valuable in analysing the complex relationships between humans and their environment.
Both sites provide evidence separately of key stages in the evolution of the fauna of the world's most isolated continent. The history of mammal lineages in modern Australia can be traced through these fossil deposits and, as a consequence, there is a better understanding of the conservation status of living mammals and their communities.
The sites, each highly significant in its own right, are presented as a serial World Heritage nomination. Together they represent the key stages in the development of Australia's mammal fauna. While there are other important Australian fossil mammal sites, Riversleigh and Naracoorte are outstanding for the extreme diversity and the quality of preservation of their fossils. They also provide links through time that unify the biotas of the past with those of today in the Wet Tropics of Queensland, the Gondwana Rainforests of Australia and Kakadu National Park World Heritage properties.
The Tertiary fossil fields of Riversleigh
are apparently confined to the watershed of the spring fed Gregory River
within the Karumba Basin in the Gulf of Carpentaria.
The Cainozoic deposits of Riversleigh occur as
inliers within eroded areas of the extensive, flat-lying, Cambrian Thorntonia limestone. This in turn surrounds less common
remnants of Proterozoic sediments. The Cainozoic
sediments can be categorised into four groups: Oligo-Miocene
alluvial and lacustrine deposits; Oligo-Miocene
karst and fissure fills; Pliocene cave sediments; and
Quaternary fluvial and cave sediments.|
Riversleigh's faunal assemblages have profoundly altered understanding about Australia's mid-Cainozoic vertebrate diversity. A 15 million-year-old complete skull and nearly complete dentition of the monotreme Obdurodon dicksoni (Archer et al. 1992, 1993) has already provided a great deal of new information about this highly distinctive group of mammals.
The recently extinct marsupial thylacine Thylacinus cynocephalus, also known as the Tasmanian Tiger, was the largest living mammalian carnivore in Australia. Before Riversleigh's fossil record began to unfold, there was only one Tertiary species known, but different thylacines have been identified from Riversleigh's Oligo-Miocene faunas (Muirhead & Archer 1990; Muirhead 1993). This record has been used (Archer l991a, Archer et al., 1992) to demonstrate the potential conservation value of understanding the prehistory of a group, although in this case understanding was obtained too late to be of value in avoiding the extinction of the Thylacine in the 1930s. Other ancestral marsupial forms found at Riversleigh include moles, bandicoot, marsupial 'lions', koala, wombat, kangaroo and possums. Placental mammals are represented by more than 35 bat species, and the Riversleigh fossil bat record is considered one of the richest in the world.
The landscape at Riversleigh, particularly near the rivers, has a large number of visible archaeological traces of Aboriginal occupation and sites of cultural significance.
|History Not Available|
|Condition and Integrity Not Available|
About 10 000ha, 70km south west of Gregory Downs,
comprising that part of Boodjamulla (Lawn Hill)
National Park inscribed in the World Heritage List in 1994.|
Archer, M. et al (1986) Uncovering Australia's Dreamtime Surrey
Beatty, Chipping North NSW. |
Archer, M. et al (1991) Riversleigh: the Story of Australia's Inland Rainforests Reed Books, Sydney.
Cochrane, R.M. and Joyce, E.B. (1986) Geological Features of National and International Significance in Australia Australian Heritage Commission, Canberra.
Gould, S.J. (1993) The Book of Life Ebury Hutchinson, London.
Rich, P.V. and van Tets, G.F. (1985) Kadimakara: Extinct Vertebrates of Australia Pioneer, Lilydale.
Report Produced Thu Jul 31 12:14:49 2014