Australian Aboriginals settled on the Australian continent somewhere between 40,000 and 60,000 years ago. Aboriginal art dates back at least 20.000 years but is likely much older. Cave painting and petroglyphs are the oldest surviving forms of aboriginal art.
Aboriginal art is often perceived to be dot dot paintings from Papunya. This form of art is by far the best known but is only one of many art traditions. Aboriginals in different regions of Australia had different cultures and different art traditions.
Aboriginal art from some regions is only now preserved on artifacts. That is why the designs on weapons and adornments are so collectable. They are the only real clues to a whole artistic tradition that is no longer practised.
To even cover the history of one form of art would take an entire book. There are numerous great books covering different regions. A good book to start is Aboriginal Australian Art by Berndt
Aboriginal art is regional in character and style. Different areas with different traditional language groups approach art in unique ways. With experience, it is obvious that different art works come from a particular community. Each language group had its own art style.
For example dot painting is specific to the Central and Western desert. Many of the designs on dot dot paintings come from an earlier tradition of carving on sacred boards.
Cross-hatching and rarrk design comes from Yirrkala in Arnhem Land.
X-ray bark paintings come from Oenpelli in Arnhem Land. They have direct links to an earlier tradition of cave painting.
Wandjina paintings come from the Kimberley in Western Australia. They depict traditional spirits associated with the rainy season.
The same is true with Aboriginal artifacts and weapons. Specific styles of weapon developed in different regions.