Australia

Australia is the smallest of the geographic continents, though not of geological continents.[1] There is no universally accepted definition of the word "continent"; the lay definition is "One of the main continuous bodies of land on the earth's surface." (Oxford English Dictionary). By that definition, the continent of Australia includes only the Australian mainland, and not nearby islands such as Tasmania or New Guinea. From the perspective of geology or physical geography, however, a "continent" may be understood to include the continental shelf (the submerged adjacent area) and the islands on the shelf, which are taken to be structurally part of the continent. By that definition Tasmania, New Guinea and other nearby islands such as (Aru Islands) are part of the Australian continent, since they are part of the same geological landmass. These islands are separated by seas overlying the continental shelf — the Arafura Sea and Torres Strait between Australia and New Guinea, and Bass Strait between mainland Australia and Tasmania. When sea levels were lower during the Pleistocene ice age, including the last glacial maximum about 18,000 BC, the lands formed a single, continuous landmass. During the past ten thousand years, rising sea levels overflowed the lowlands and separated the continent into today's low-lying semi-arid mainland and the two mountainous islands of New Guinea and Tasmania. Geologically, the continent extends to the edge of the continental shelf, so the now-separate lands can still be considered a continent.[2] Due to the spread of flora and fauna across the single Pleistocene landmass, the separate lands have a related biota. New Zealand is not on the same continental shelf and so is not part of the continent of Australia but is part of the submerged continent Zealandia. Zealandia and Australia together are part of the wider region known as Oceania or Australasia. Contents[hide] 1 Geography and nomenclature 2 Geology 3 Biogeography 4 See also 5 References