The Treasures of Lake Mungo
The Walls of China, Lake Mungo.
It was Jim Bowler’s fascination with landscape formation that attracted him to the relict lake systems of south-western NSW. The semi-arid environment of this region contains evidence of hundreds of lake-beds – at times some still hold water while the majority are covered with vegetation and have been dry for thousands of years.
Professor James Bowler is a geomorphologist whose main interest focusses on how the landforms and soils in arid and semi-arid areas of Australia form and how the hydrology of ancient Australia assisted in the creation of these landscapes. It was this interest that led him to Lake Mungo and the relict landscapes around its shores. More recent erosive events have exposed landform elements that allow geomorphologists to view how they form and how responsive some landforms are to climatic and/or hydrological change.
During one of his visits in 1968 Professor Bowler found some bone eroding out of a dune near the eastern flanks of Lake Mungo. He recognized this bone as being of human origin. The resultant investigation led to the conclusion that the burial of the human remains took place over 40,000 years ago and is now known as the oldest known ritual cremation in the world. These fragmented skeletal remains became known as Mungo Lady. Some years later another set of human remains were located nearby and these became known as Mungo Man – an almost complete skeleton that has been dated to over 42,000 years BP (before present).
Lake Mungo is one of several lakes that are now contained within the ‘Willandra Lakes World Heritage Area’. Mungo is not the largest of the lakes, with that privilege being taken by Lake Garnpung, a lake that is almost three times the size of Lake Mungo. Furthermore, Lake Mungo was not directly fed by Willandra Creek, the paeleo-channel that links most of the other lakes in the system. Lake Mungo was filled by an over-flow channel out of Lake Leaghur immediately to its north. If Lake Leaghur was not full, the incoming flow of water from the Willandra Creek had no impact on the water levels of Mungo.
Map showing lake locations and boundary of World Heritage Area - click to enlarge.
Lake Mungo is about 25 kms long and a high crescent dune of clay and sand is located along its eastern flank – a feature common to most of the dry lakes of this region and known as a ‘lunette’. The Mungo lunette, at least part of it, is known as the ‘Walls of China’ - possibly named by (or after) the Chinese workers who built the Mungo woolshed in 1869. Beyond the dune, mallee scrub extends to the horizon, placing into perspective the picture of what used to be a green oasis inhabited by mega-fauna including giant tree-browsing kangaroos, three-metre-tall emus and massive Zygomaturus. The lake would have been teeming with perch, Murray Cod and water-fowl.
The megafauna became extinct in the Willandra Lakes region by the end of the last Ice age around 10-14,000 years ago, probably from a combination of the drying up of surface water and, possibly, as a consequence of hunting. The water-fowl left with the water. Such an environment is likely to have been seen as ‘utopian’ by the first humans to arrive in the area. Jim Bowler’s discoveries certainly indicate that the first human inhabitants arrived tens of thousands of years ago but what other archaeological evidence has been found in this area?
Lake Mungo – view from its western shore with the Walls of China on the eastern shore in the far distance.
When the first Aboriginal people arrived in the area, Lake Mungo was one of the numerous lakes located along an ancient channel of the Lachlan River. During this period conditions for the first inhabitants were much more favourable than today. The climate was cooler and there was less evaporation which meant that the lakes were full of fresh water. Fish and waterfowl were plentiful and a range of mammals lived around its shores.
Around 15,000 years ago the climate became drier, the Lachlan River changed to its present course and the Willandra Lakes eventually dried up. Over the millennia, the landscape was rarely static, always responding to the varied climate and environmental conditions. The landforms that we see today reveal a palimpsest, the result of landforms building up and wearing down as the years passed. Evidence of human occupation is also contained within these landforms.
The stark, eerie desert beauty of Lake Mungo.
The earliest soils in the area, called the Gol Gol sediments, are contained within a dune laid down about 120,000 years ago. About 45,000 years ago the lakes filled and from about 45-26,000 years ago, the lakes mainly remained full and sand from the lakeside beaches was thrown up on the eastern shore to form a crescent dune. This dune consists of Gol Gol, Mungo and Zanci units. The Mungo unit is the oldest sediment to contain stone artefacts or other remains of human presence; no such remains have been found in the underlying Gol Gol unit. From 16-26,000 years ago the lakes fluctuated and by 14-15,000 years ago the Willandra Lakes no longer existed.
While the lakes were brimming with freshwater fish and shellfish, Aboriginals camped, fished and hunted on the dunes bordering the lake shore. They collected vegetable foods, mussels, frogs, yabbies and speared fish including Murray Cod and Golden Perch. Their diet also included land animals, such as lizards, wallaby and wombat, together with duck and emu eggs. After the lakes dried up, Aboriginal groups still passed through the area but may not have stayed for extended periods unless there were waterholes to provide for them. They would have focused their activities on the more permanent water source such as the Murrumbidgee, Darling and Lachlan Rivers.
Kangaroo during sunset at Mungo National Park.
The discovery of early human remains within the Willandra Lakes area resulted in much more detailed archaeological investigation that continues to this day. Over 100 burials have been identified but the majority of those were recorded in situ and remain in place – albeit protected from further disturbance. The significance of the Willandra Lakes Region was recognized when it was inscribed on the World Heritage List in 1981. However, the ‘treasures’ of Lake Mungo are much more diverse than sets of human remains.
The most enduring evidence of Aboriginal occupation can be seen with the scatters of stone that are scattered about within the dunes or along the relict lake shores. The soils in and around the lake systems is such that there is very little bedrock visible. Those fragments that are seen on the ground are, in the main, Aboriginal artefacts that are lying where they were discarded, perhaps thousands of years ago, or have been displaced by the actions of wind and water erosion from their original location. Some of the artefacts are made of material that is not found locally. Sandstone slabs were often used as grinding stones – to grind seeds of grasses or acacia. Quartzite cobbles, made of a much harder stone, can be used anvils. Quartzite and sandstone artefacts were traded into the region from some distance away, possibly from the Barrier Range near Broken Hill, one of the closest areas where this type of stone can be found and at least 250 kms away.
The majority of stone artefacts found in the area are made of silcrete. This hard but brittle stone can be knapped to make sharp flakes, scrapers and points – all part of the tool-kit employed by the Aboriginal inhabitants. Literally thousands of silcrete artefacts, including some tools, can be seen lying on the ground surface in this area. The source of this stone is local – one quarry is found outcropping on the western shore of Lake Mungo and another source is known on the southern side of Lake Leaghur.
For me, the most revealing evidence relating to early human occupation is found in the middens that often appear as dunes erode or deflate. Sometimes known as ‘shell middens’ these features contain a lot more than just shell. Some regard them as rubbish heaps but rubbish from the past provides valuable information if archaeologists are to recreate, at least on paper, how Aboriginal people lived in this area. Middens contain the remains of past meals and are made of thousands of fragments from shell, bone, ash and the cooking fires themselves.
A midden consisting almost entirely of freshwater mussel – nothing special about that, except this lake hasn’t held water for 14,000 years!
By closely examining this evidence archaeologists can determine what was being consumed and how long ago that took place. From that, we can build up a picture of where food was sourced and how is was collected. Some individual items can even reveal a more detailed picture to determine what the climate was like at a particular time and see how that may have changed over time.
One of the smallest elements that are found in middens are otoliths. These tiny bones are located within a fish’s head. Being the hardest bone in a fish’s body, they remain long after the rest of its skeleton has disappeared. Each species of fish has a uniquely shaped otolith so when we find an intact specimen we can determine what species it came from. By comparing it to collected samples, we can determine how big the fish was when it was caught.
Otoliths – not a pair as these two both come from the same side of a fish’s head.
To go even further, we can thin section otoliths and not only determine how old the fish was when it died (otoliths have features similar to growth rings in a tree) but we can also sample stable isotopes within its structure (particularly oxygen isotopes) and certain combinations of such isotopes can inform us the temperature of the water that the fish was swimming in when it was alive. Now that shows how much of an archaeological treasure otoliths are!
Middens can reveal a plethora of evidence relating to early lifeways but the nature of the landforms around Lake Mungo are such that as quickly as material is revealed, it disappears or dissipates. Without a concerted and continual monitoring presence, much of the evidence goes unnoticed. That being said, archaeological investigations continue and the Traditional Owners, as best they can, keep a watchful eye on the heritage of Lake Mungo.
Lake Mungo’s treasures continue to be revealed. I first visited the area over 30 years ago and return most years. It is one of those places that contains an abundance of archaeological evidence and every time I return, even when visiting the same spots, I am always seeing something new – and exciting.
Explore Lake Mungo in 2023
A visit to World Heritage-listed Lake Mungo is one of the core experiences of our 10-day itinerary - From the Edge of the Outback - scheduled for this October with Dr Chris Carter.
The tour takes you from the storied mining town of Broken Hill in western NSW to the Victorian border town of Mildura, discovering ancient indigenous sites while traversing the notoriously fickle river systems of the Murrumbidgee and Darling.
