Lake Mungo is a dry lake

Lake

A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

 in south-western New South Wales

New South Wales

New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...

, Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

. It is located about 760 km due west of Sydney

Sydney

Sydney is the most populous city in Australia and the state capital of New South Wales. Sydney is located on Australia's south-east coast of the Tasman Sea. As of June 2010, the greater metropolitan area had an approximate population of 4.6 million people...

 and 90 km north-east of Mildura

Mildura, Victoria

Mildura is a regional city in northwestern Victoria, Australia and seat of the Rural City of Mildura local government area. It is located in the Sunraysia region, and is on the banks of the Murray River. The current population is estimated at just over 30,000.Mildura is a major agricultural centre...

. The lake is the central feature of Mungo National Park

Mungo National Park

Mungo National Park is an isolated national park in south-western New South Wales, Australia, 876 km west of Sydney, in the Balranald Shire. It is part of the Willandra Lakes Region, a World Heritage Site covering 2,400 square kilometres, and incorporating seventeen dry lakes...

, and is one of seventeen lakes in the World Heritage listed

World Heritage Site

A UNESCO World Heritage Site is a place that is listed by the UNESCO as of special cultural or physical significance...

 Willandra Lakes Region

Willandra Lakes Region

The Willandra Lakes Region is a World Heritage Site that covers 2,400 square kilometres in south-western New South Wales, Australia.The Region contains important natural and cultural features including exceptional examples of past human civilization including the world's oldest cremation site...

. Many important archaeological

Archaeology

Archaeology, or archeology , is the study of human society, primarily through the recovery and analysis of the material culture and environmental data that they have left behind, which includes artifacts, architecture, biofacts and cultural landscapes...

 findings have been made at the lake, most significantly the discovery of the remains of Mungo Man, the oldest human remains found in Australia, and Mungo Lady, the oldest human remains in the world to be ritually cremated.

Geology

Sediment

Sediment

Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....

s at Lake Mungo have been deposited over more than 100,000 years. On the eastern shore of the lake are the 'Walls of China', a 26 km long series of lunette

Lunette

In architecture, a lunette is a half-moon shaped space, either filled with recessed masonry or void. A lunette is formed when a horizontal cornice transects a round-headed arch at the level of the imposts, where the arch springs. If a door is set within a round-headed arch, the space within the...

s, about thirty metres high, formed over thousands of years. There are three distinct layers of sands and soil forming the Walls. The oldest is the reddish Gol Gol layer, formed between 100,000 and 120,000 years ago. The middle greyish layer is the Mungo layer, deposited between 50,000 and 25,000 years ago. The most recent is the Zanci layer, which is pale brown, and was laid down mostly between 25,000 and 15,000 years ago.

The Mungo layer, which was deposited before the last ice age

Ice age

An ice age or, more precisely, glacial age, is a generic geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental ice sheets, polar ice sheets and alpine glaciers...

 period, is the most archaeologically rich. Although the layer corresponded with a time of low rainfall and cooler weather, more rainwater ran off the western side of the Great Dividing Range

Great Dividing Range

The Great Dividing Range, or the Eastern Highlands, is Australia's most substantial mountain range and the third longest in the world. The range stretches more than 3,500 km from Dauan Island off the northeastern tip of Queensland, running the entire length of the eastern coastline through...

 during that period, keeping the lake full. It supported a significant human population, as well as many varieties of Australian megafauna

Australian megafauna

Australian megafauna are a number of large animal species in Australia, often defined as species with body mass estimates of greater than 30 kilograms, or equal to or greater than 30% greater body mass than their closest living relatives...

.

During the last ice age period, the water level in the lake dropped, and it became a salt lake. This made the soil alkali

Alkali

In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal element. Some authors also define an alkali as a base that dissolves in water. A solution of a soluble base has a pH greater than 7. The adjective alkaline is commonly used in English as a synonym for base,...

ne, which helped to preserve the remains left behind in the Walls of China. Although the lake completely dried up several thousand years ago, ground vegetation remained on the Walls, which helped to stabilise them and preserve them. With the arrival of European settlers in the area since the 1880s, introduced species, notably rabbit

Rabbits in Australia

In Australia, rabbits are a serious mammalian pest and are an invasive species. Annually, European rabbits cause millions of dollars of damage to crops.-Effects on Australia's ecology:...

s and sheep, have destroyed the vegetation cover. Herds of feral goat

Goat

The domestic goat is a subspecies of goat domesticated from the wild goat of southwest Asia and Eastern Europe. The goat is a member of the Bovidae family and is closely related to the sheep as both are in the goat-antelope subfamily Caprinae. There are over three hundred distinct breeds of...

s are also present in the region. This has led to increased erosion

Erosion

Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

 of the dunes. However, this erosion has led to the uncovering of many human and animal remains. Wind has moved sand and soil eastwards from the Walls, forming a mobile sand dune which moves further east every year.

Archaeology

The most important findings at Lake Mungo have been Mungo Man and Mungo Lady. Mungo Lady, a partially cremated

Cremation

Cremation is the process of reducing bodies to basic chemical compounds such as gasses and bone fragments. This is accomplished through high-temperature burning, vaporization and oxidation....

 body, was discovered in 1969 by Dr Jim Bowler from the Australian National University

Australian National University

The Australian National University is a teaching and research university located in the Australian capital, Canberra.As of 2009, the ANU employs 3,945 administrative staff who teach approximately 10,000 undergraduates, and 7,500 postgraduate students...

 (ANU). She was initially estimated to be 25,000 years old, although a more recent multi-university study in 2003 determined that she was probably closer to 40,000 years old. Mungo Lady is thus the earliest known human to have been cremated. Mungo Man was also discovered by Dr Bowler, on 26 February 1974. The remains were covered with red ochre

Ochre

Ochre is the term for both a golden-yellow or light yellow brown color and for a form of earth pigment which produces the color. The pigment can also be used to create a reddish tint known as "red ochre". The more rarely used terms "purple ochre" and "brown ochre" also exist for variant hues...

, in what is the earliest known incidence of such a burial practice. Although some studies have estimated his age at more than 60,000 years, the current consensus is that he is also about 40,000 years old.

There is evidence of human habitation of the area around Lake Mungo that is as much as 50,000 years old. Stone tools have been found in the dunes which are older than the Mungo Man. Grinders for making flour

Flour

Flour is a powder which is made by grinding cereal grains, other seeds or roots . It is the main ingredient of bread, which is a staple food for many cultures, making the availability of adequate supplies of flour a major economic and political issue at various times throughout history...

 have been found which are estimated to be between 5,000 and 10,000 years old; they were made of sandstone

Sandstone

Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

 sourced from the Murray River

Murray River

The Murray River is Australia's longest river. At in length, the Murray rises in the Australian Alps, draining the western side of Australia's highest mountains and, for most of its length, meanders across Australia's inland plains, forming the border between New South Wales and Victoria as it...

 basin 100 km away. A stone axe head, estimated to be at least 500 years old, was also found in the dunes; it was made from stone from Mount Camel, near Shepparton

Shepparton, Victoria

Shepparton is a city located on the floodplain of the Goulburn River in the north east of Victoria, Australia approximately north-east of Melbourne. It is the fifth largest city in Victoria, Australia. The estimated population of Shepparton's statistical area is 48,926.It began as a sheep station...

, well over 300 km away.

The poor archaeological heritage of the site is very significant to the Aboriginal Australian people from the area. The Willandra region is inhabited by the Barkindji, Nyiampaa and Mutthi Mutthi peoples, who have now entered Joint Management Agreements with the Government of New South Wales

Government of New South Wales

The form of the Government of New South Wales is prescribed in its Constitution, which dates from 1856, although it has been amended many times since then...

 to manage the lake and the Mungo National Park

Mungo National Park

Mungo National Park is an isolated national park in south-western New South Wales, Australia, 876 km west of Sydney, in the Balranald Shire. It is part of the Willandra Lakes Region, a World Heritage Site covering 2,400 square kilometres, and incorporating seventeen dry lakes...

.