According to Oppenheimer, modern humans first began arriving in Australia from islands across the Timor Sea during the Middle Paleolithic era, between 70,000 and 60,000 BCE.
Evidence of the ancient art (if any) of this first wave of aboriginal settlers is extremely scarce, but there are signs of pigment usage which suggest that they began painting almost immediately, although this might have been face or body painting rather than rock painting.
Other, possibly even older examples of prehistoric art (cupules) have been discovered in the granite rock shelter of Turtle Rock, Northern Queensland, and in the dark limestone caves of southern Australia.
Australian Aborigine artists have continued to practice their traditional arts and crafts into the modern era, creating in the process a unique and unbroken record of artistic expression.
All this means that aboriginal migrants were settled in Australia some 10,000 years before their northern counterparts arrived in Europe.
As well as rock engravings and cave painting, it includes various forms of prehistoric sculpture.
Aboriginal rock painting includes at least five different styles: (1) X-ray and cross-hatch art from the Arnhem Land and Kakadu regions of Northern Australia - a style of painting in which the insides of animals and humans are depicted, as if X-rayed.
Unfortunately, over time, some aboriginal caves and rock shelters have become saturated with superimposed imagery as well as artifacts from a great many occupations.
As a result, even though Australia is home to more petroglyphs and pictographs than any other country in the world, the sheer number of these cave paintings and rock engravings places a heavy burden on the country's limited archeological resources.