The Great Artesian Basin is a 1.7 million square kilometre bed of porous water holding sedimentary rock lying on average 1000meters beneath most of northeastern Australia (22% of Australia’s total land area). Water, which fell as rain on the Great Dividing Range in Queensland and some say in areas of Papua New Guinea, takes over 1 million years to seep down into South Australia. There is also minor recharge from the western edge of the basin. 

The basin was created during the Mesozoic period, 65 to 248 million years ago, where the area slumped under the weight of an Inland Sea and it's deposits. The sediments formed porous rock, mainly sandstones, to be capped later by impervious shales. To balance the slumping, land at the eastern rim rose. Wherever the raised edge of the porous layer has been exposed (aquifer) it acts as a conduit for water. It is sealed in the basin by impervious rock layers (aquitard). Tremendous pressure builds up, and the water finds it's way to the surface either by natural methods in the form of vertical leakage and mound springs, or through the drilling of bores.

Fault action along the south western edge of the basin has resulted in a line of mound springs, stretching from Lake Callabonna at the north east edge of the Flinders Ranges, to Alice Springs in the south of the Northern Territory. These are the surface expression of the Great Artesian basin.

Diamantina Touring Company offer extensive programs around various parts of the Great Artesian Basin. For information on those tours, click here.