b'The Australian continent: A geophysical synthesisFeatureFigure 1.Topography of the Australian continent and bathymetry of the surrounding oceans. The state boundaries and state capitals are also indicated.tapering off in the winter dry. After a particularly heavy wet,coast and the base of the abyssal plain sometimes reaching sufficient water can reach and fill the Lake Eyre basin that lieswithin 60 km of the coastline (Figure 1). The conjugate southern below sea level. margins of Australia along the Great Australian Bight and the Although the glaciation in the Permo-Carboniferous had aAntarctic coast, created by the opening of the Southern Ocean, broad impact on continental Australia, the last ice ages had onlyshow somewhat wider continental shelves.limited impact on the physiography. The Australian continentThe broad continental shelf off Queensland, left behind after was already at fairly low latitudes in the Pleistocene, so thatthe Coral Sea opened, forms a foundation for the Earths glaciation was confined to small areas in southeastern Australia,largest single living entitythe Great Barrier Reefwith 2900 with little reworking of the older landscape. reefs, 600 continental islands and 300 coral cays created in The continental slope on all margins is deeply incised, witha mixed siliciclastic- carbonate depositional environment. steep-sided canyons up to 2 km deep, reflecting either extinctThe wide continental shelf between the coast of northern drainage systems or the drowned valleys of current riverAustralia and Indonesia, Timor and New Guinea represents systems (such as the Perth Canyon in West Australia). On thethe drowned remnants of the former single landmass. The southern part of the eastern margin, the continental shelf isextended continental shelf off Western Australia is host to most rather narrow, with a shelf break closer than 20 km from theof Australias natural gas resources, and is marked by complex APRIL 2019 PREVIEW 40'