The Kallakoopah fossil record
The Kallakoopah area has a rich fossil history, with plenty of areas still relatively unexplored.
Earlier fossil finds show an abundance of animal activity in the interglacial period, before the ice age. On this expedition Dr Mike Smith was on the look out for signs of Thylacoleo, a giant marsupial lion which was likely to have roamed across the Kallakoopah, though no known fossils have been found.
Signs of Aboriginal occupation are evident in more recent times and Mike expected to find many campsites.
Very little is known about the people who might have lived in the area at the end of the ice age and the expedition could well make a major contribution in this respect.
Here, before he set out on the expedition, Mike reflects on the known archaeology of the area.
Life and lakes in the last interglacial
The last interglacial and its immediate aftermath, dating from 65,000 to 130,000 years ago is the best-known time period on the Kallakoopah.
It was a period of deepwater lakes and higher river discharge throughout this region. The Kallakoopah-Coopers Creek region appears to have been a mosaic of river channels, deep waterholes, well-watered back swamps, floodplains, and gallery woodland.
Lake Eyre was a deep freshwater lake until about 100,000 years ago, when drier conditions are marked by a series of oscillations in lake level, with the lake switching between shallow brackish or dry conditions and deepwater conditions – and back again – before finally drying up 60,000 years ago.
Local fossils from this period are abundant and include diprotodons, crocodile, saratoga-size fish, large freshwater turtle and Megalania prisca, a Komodo-dragon size varanid lizard.
Thylacoleo, the marsupial lion, does not appear to have been found yet in these fossil assemblages – but this large predator is known to have been wide ranging and is very likely to have been present in the Kallakoopah-Coopers Creek area. It has distinctive large wedge-shaped premolar teeth – which were used to shear through bone (think of Thylacoleo as a panther-sized possum with teeth like bolt-cutters).
Here you will find that fossil bone is highly fragmented – and often forms the bulk of the gravel deposits and bars in the channels. There is no stone, so most of the gravel will be thumbnail-sized pieces of fossil bone. The main sedimentary unit for this period is known as the Katapiri formation.
As this is also a period before humans entered the Australian continent, we do not expect to find any archaeological remains associated with these fossil deposits. However, the final disappearance of the mega fauna in this area (about 65,000 years ago) is close to the earliest dates for humans elsewhere in Australia (50,000 to 55,000 years ago) so there is always a possibility of some co-existence and overlap. This might take the form of ancient fireplaces containing burnt megafauna bone, or perhaps thylacoleo scats containing fragments of human bone (tooth crowns would generally survive the digestive process).
One species that did survive in this area until 45,000 to 50,000 years ago is Genyornis. G. newtonii was a large flightless ratite bird, rather like a larger, more robust emu, but more closely related to geese. Bones of Genyornis are fragile and rarely preserve in these deposits. However, as it was a ground laying bird, with nests containing two to three eggs, its eggshell is widespread in aeolian deposits throughout the Lake Eyre region. Genyornis eggshell can be distinguished from emu eggshell because it has a smooth surface and is thick and solid, rather than textured and laminated like emu.
Limited traces from the last ice age
The only trace of human use of the northern Lake Eyre region before 13,000 BP* is a single fireplace. This included a scatter of emu eggshell and stone artefacts on the eastern shore of Lake Eyre near Madigan Gulf. This has been dated to 18,000 BP.
As the last ice age came to a close, global climate warmed and local rainfall increased in the Pleistocene period. In the Coopers Creek and Strzelecki area, erosion often reveals ancient fireplaces within dune cores, or exposed on claypans.
These tend to date to around 12,000 to 13,000 years ago and reflect a period when Aboriginal people were recolonising parts of the desert that had been abandoned during the intense aridity of the last ice age (which peaked 18,000 to 20,000 BP).
It is likely that similar remains will be found along the Kallakoopah – wherever erosion has cut into the core of old linear dunes.
These ancient fireplaces are often associated with a zone of carbonate enrichment or sometimes carbonate rhizomorphs (calcrete formed around tree roots). Both mark an incipient soil horizon associated with the wetter conditions at this time.
Very little is known about the details of Aboriginal occupation of the area at this time and the expedition could well make a major contribution in this respect.
Recent Aboriginal occupation
Almost nothing is known of the recent prehistoric occupation of the Kallakoopah region of the Simpson Desert. Historically, the area was part of the territory of the Wangkanguru people.
There is also abundant evidence of prehistoric occupation along Strzelecki Creek back to 4000 BP and also along the lower Cooper after this time.
On the Kallakoopah and lower Warburton we can expect to find numerous traces of Aboriginal occupation during the last 3000 years. These might include chipped stone artefacts, pieces of grindstones, scatters of Velesunio shells (food debris) and old fireplaces, some with burnt clay heat-retainers. Because of the lack of outcropping stone in this area most stone artefacts will be heavily worked down.
It is also likely that some ephemeral waterholes were focal places for large seasonal gatherings of people (as was the case around the Coongie Lakes to the east), wherever and whenever floodwaters filled waterholes. We may well find larger campsites in these areas, with chipped stone, burnt clay, shells, grinding stones (for plant foods like seeds), and ochre scattered over several hundred metres.
* BP stands for Before Present, a standard unit of time used by scientists for radiocarbon dating.