How did plate tectonics play a role on the formation of Australia as an island continent?
Australia was originally part of the ancient continent of Gondwanaland, which had earlier formed part of the supercontinent of Pangaea. Much of it is geologically ancient; the oldest known rock formations have been dated at between 3 and 4.3 billion years old. The great plateau of the Western Australian Shield is underlaid by a vast, stable shield of Precambrian metamorphic and igneous rocks, ranging in age from 570 million to 3.7 billion years. These form the core of the ancestral continent, which, with Antarctica, split off from Gondwanaland during the Jurassic era, less than 200 million years ago, and began to drift eastwards and northwards. Australia emerged as a separate continent about 100 million years ago, when Antarctica broke away and drifted southward. Australia is still moving, northwards, away from Antarctica and is in the process of merging with Asia. Its life as a separate continent will be relatively short, in geological time.
