The continent of Australia consists of the landmasses which sit on Australia’s continental plate. This includes mainland Australia, Tasmania, and the island of New Guinea, which comprises Papua New Guinea and Indonesia‘s Western New Guinea. Situated in the geographical region of Oceania, it is the smallest of the seven traditional continents in the English conception.
The continent includes a continental shelf overlain by shallow seas which divide it into several landmasses—the Arafura Sea and Torres Strait between mainland Australia and New Guinea, and Bass Strait between mainland Australia and Tasmania.
The Australian continent, being part of the Indo-Australian plate (more specifically, the Australian plate), is the lowest, flattest, and oldest landmass on Earth and it has had a relatively stable geological history.
With a total land area of 8.56 million square kilometres (3,310,000 sq mi), the Australian continent is the smallest, and second-lowest human-inhabited (after Antarctica) continent on Earth. The continental shelf connecting the islands, half of which is less than 50 metres (160 ft) deep, covers some 2.5 million square kilometres (970,000 sq mi), including the Sahul Shelf and Bass Strait.
As the country of Australia is mostly on a single landmass and comprises most of the continent, it is sometimes informally referred to as an island continent, surrounded by oceans.
The continent primarily sits on the Indo-Australian Plate. Because of its central location on its tectonic plate, Australia doesn’t have any active volcanic regions, the only continent with this distinction. Australia has a huge variety of animals; some 83% of mammals, 89% of reptiles, 24% of fish and insects and 93% of amphibians that inhabit the continent are endemic to Australia.
When the last glacial period ended in about 10,000 BC, rising sea levels formed Bass Strait, separating Tasmania from the mainland. Then between about 8,000 and 6,500 BC, the lowlands in the north were flooded by the sea, separating New Guinea, the Aru Islands, and the Australian mainland.