Great Artesian Basin
Also found in: Acronyms, Wikipedia.
Great Artesian Basin,c.670,000 sq mi (1,735,300 sq km), between the Eastern Highlands and the Western Plateau, E central Australia, extending S from the Gulf of Carpentaria, Queensland, to NE South Australia and N New South Wales. It is the world's largest artesian water-bearing area. The arid basin receives water from the Eastern Highlands as rain is absorbed by porous rock and flows underground toward the center of the saucer-shaped basin. Thousands of wells, some over 1 mi (1.6 km) deep, tap underground water-bearing rock formations. The rolling surface of the basin supports a pastoral economy mainly based on livestock watering systems. The highly mineralized artesian water cannot be used for agriculture.
Great Artesian Basin
the largest artesian basin in Australia, the second largest in the world (after the Western Siberian in the USSR). Area, 1,736,000 sq km.
The Great Artesian Basin stretches for more than 2,200 km from the shores of the Gulf of Carpentaria to the central section of the Darling River and is almost 1,800 km broad from west to east in the southern section, which is the widest. It was formed by the downwarp of an ancient crystal basis, which had been filled with sedimentary layers up to 2,500 m thick, dating from the Paleozoic to the Neocene periods. The main water-bearing layers are Mesozoic sandstone.
Groundwater is replenished mainly by atmospheric precipitation, which falls on the western slopes of the Great Dividing Range (approximately 625 mm annually). The waters, which often have mineral content, collect at a great depth (up to 2,000 m); in the region of Eyre Lake, mineral springs are frequent at the surface. Their temperature increases in proportion to the layer at which they lie, on the average, 1°C for each 32.5 m. The highest temperature (110° C) is found in Queensland. Most wells are in the arid cattle-raising region, where water is pumped to the surface and protected from evaporation in closed water cisterns. The basin is also used as a water supply for industrial purposes as far as the mineral content will permit.