The landforms of today are the result of prolonged, continuous processes of movement and erosion over millions of years giving rise to a variety of landscapes across Australia.
These are continuing to undergo change as the continent moves north.
The past few million years were notable for the Quaternary ice age which resulted in various glacial and interglacial periods.
The last glacial period was at its most intense about 20 000 years ago, and by around 11 700 years ago the ice had retreated and rising sea levels separated mainland Australia from Tasmania and New Guinea.
Recently, scientists have been able to obtain a much clearer picture of Australia's geological past through deep seismic surveys, which has provided new information about how the continent was formed, particularly around Broken Hill, Mount Isa, .
Although the shape of Australia is due largely to tectonic Earth movements and long term changes in sea level, most of its topography is a result of prolonged erosion by wind and water.
Australia's youngest mainland volcano is Mt Gambier in South Australia which last erupted only about 6000 years ago.
During this event ice covered about 25 square kilometres in the vicinity of Mt Kosciuszko, with the most significant remnant being the Blue Lake cirque.Australia's present topography is the result of a long landscape history, which, fundamentally, started in the Permian Period when Australia was very near the South Pole, and much of the continent was glaciated by large ice caps.After the ice melted, parts of the continent subsided and formed sedimentary basins such as the Eromanga Basin in South Australia.About 50 per cent of Australia's rivers drain inland and often end in ephemeral salt lakes.Many of the features of the drainage pattern have a very long history, and some individual valleys have maintained their position for millions of years.