How did the Great Inland Sea form and where did it go?
140 million years ago: Sea levels rose submerging much of inland Australia. The weight of this water helped the earth’s crust to subside, allowing further invasion by the sea. Ocean currents covered the land in sand and mud, causing the vast flatness you see today. These layers filled the Great Artesian Basin. Cracks in the clay under that ancient sea now allow drainage within the Basin, and provide the region with its groundwater, or bore water. 110-100 million years ago: Australia still sat well south of the equator, at latitude 55 degrees S. However, the continent slowly travelled north as violent volcanic eruptions and movements in the Earth’s crust tore eastern Gondwana apart. The remains of marine reptiles were fossilized within the Basin’s sediments. 98-95 million years ago: Australia continued its slow drift northward reaching 45 degrees below the equator. The climate warmed and the last inland sea retreated, leaving behind temperate forests and open plains in Queensland’s Outb
