While the Great Dividing Range runs up the east edge of Australia and various highlands are scattered along its periphery, the Continent is dominated by flat terrain; there are certainly no ranges comparable to the Andes, the Rockies, the Alps or the Himalayas in Australia. However, that has not always been the case.
Back in the Precambrian Era, about 1 billion years ago, a massive, snow-capped range was lifted across the center of Australia, stretching east to west; while erosion began to demolish this lofty range as soon as it formed, subsequent uplifts occurred 500 million years ago (MYA) and 300 MYA. Today, the remnants of those orogenies, known as the MacDonnell Ranges, are a swath of relatively low ridges and hills (with maximum elevations below 5000 feet) that stretch for 400 miles across the southern edge of the Northern Territory, just north of Alice Springs. Another great mountain range, the Petermann Ranges, crumpled skyward about 600 MYA and its residual swath of hills and ridges (all below 4000 feet) now stretch about 200 miles, from the east-central border of Western Australia to the northwestern corner of South Australia.
These great ranges were forced up by continental collisions back when Australia was attached to Antarctica and, at times, to other land masses. Once Australia broke from Antarctica (by 80 MYA) and drifted into prolonged isolation, it was no longer subjected to such tectonic forces and the great central ranges gradually eroded, spreading vast aprons of sediment across the Red Center of the Continent. Today, Australia sits near the center of its vast tectonic plate, far from the subduction and collision zones that ring the edge of the plate. Those who hope to see a towering alpine range in Australia will have to wait until one of its bordering oceans stops spreading and completely subducts, allowing the Continent to collide with Antarctica, Asia or, perhaps, the new Continent of East Africa.
