Australia: The Land Where Time Began

A biography of the Australian continent 

Salinas and claypans are 2 of the forms that characterise the desert plains of central Australia. They have a big range of sizes, from a few tens of metres to more than a kilometre across. The largest lakes, such as Lake Eyre, Lake Gairdner, Lake Frome, Lake Amadeus, Lake Torrens and Lake Disappointment, are each several thousand square kilometres in area.

The large salinas can be divided into 2 groups, according to their origins. Lakes like Lake Eyre and Lake Torrens result, at least in part, from tectonic processes. Other lakes originate from dismembered drainage systems, Lake Disappointment, Lake Amadeus, Lake Barles, Lake Lefroy and The Serpentine, occupying blocked palaeovalleys like Lake Gairdner. Some of the salinas and claypans may also have originated from blocked drainages, others may be due to wind erosion (deflation), and solution of the local bedrock.

Of Australian salinas, Lake Eyre is the most famous and best studied. In 1840 the first white explorer to see Lake Eyre was E.J.Eyre. It comprises 8030 kl² of Lake Eyre North and the 1300 km² and Lake Lake Eyre South. The 2 sections of Lake Eyre are linked by the Goyder Chanel. . The crust of salt on the lake bed is 50 cm thick in the south and reduces to almost nothing in the northern part. The full lake bed lies below sea level, but the lowest point is difficult to define, because its precise location varies with time, depending at least partly on salt crystallisation. It is always near the southern margin of Lake Eyre North, averaging about 17 m below sea level. It is always in one of the bays, Belt Bay, Jackboot Bay or Madigan Gulf.

Lake Gregory, Lake Blanche and Lake Callabonna are probably on fracture zones. Lake Gairdner is a flooded river valley in the Gawler Ranges. Some of the western desert salinas, such as Lake Amadeus are thought to have originated from late Cainozoic warping that blocked rivers. Most of these were located in palaeochannels, occurring in long lines characterised by fluvial sediments. Structure controlling the drainage is indicated by the fact that many are aligned.

Some of the most notable of the palaeodrainage salinas are Lake Percival, Lake Throssell, Lake Raeside and Lake Lefroy. These are thought to reflect the later Cainozoic onset of aridity. 

1. Mary E White, Running Down, Water in a Changing Land, Kangaroo Press, 2000
2. Twidale, C.R. & Campbell, E.M., 2005, Australian Landforms: Understanding a Low, Flat, Arid, and Old Landscape, Rosenberg Publishing Pty Ltd.

• Aridification of Australia
• Glacial Maximum
• Dunes