Australia: The Land Where Time Began

A biography of the Australian continent 

Overview – The Desert Before People - Interglacial Landscapes

In the last interglacial the Australian interior landscapes would have been covered by open, arid woodlands across much of the inland. On the margins of the deserts and in the Lake Eyre basin the landscape included significant lacustrine and fluvial systems in semi-arid and arid landscapes. The interior outside these areas was landscape of saltlakes and xeric vegetation stabilising desert dunes.

At Lake Gregory and Lake Woods in the north, and in the southeast, the Willandra Lakes there were active freshwater lakes on the desert margins. Streams originating outside the desert fed these terminal lakes, and it is believed they were all rich in fish, crustaceans or shellfish. Lake Eyre, in the heart of the continent, was a large, deep, saline lake during the interglacial. It was a greatly expanded lake that incorporated Lake Callabonna and Lake Frome. It was a terminal lake that was fed by rivers that arose in the subtropics, though the lake was too saline to provide significant resources for humans to exploit; apart from the ephemeral resource booms at the times nutrients and fish were flushed into the lake from connecting river systems.

The richest resource zone associated with the lake is the lower and middle reaches of the Cooper-Diamantina channels. At these sections the rivers supported a rich biota – fish, crocodiles, turtles, freshwater mussels and waterfowl. A diverse array of large herbivores was supported by a regional mosaic of swamps, floodplains and riparian woodlands, with this megafauna being tethered to major channels and floodplains. These animals were rare in open desert away from the floodplains, the greater part of the interior not supporting comparable megafaunal communities.

The area of the Cooper-Diamantina was not typical of the desert, as the western half of the continental interior didn’t have the long coordinated river systems like those present in the Lake Eyre basin. There were no active lakes, saline or otherwise, in the western half of the desert during the Quaternary: here there were old lake basins from the Miocene that were not saltlakes. In Central Australia by the late interglacial Lake Amadeus and Lake Lewis had become hypersaline playas.

Sources & Further reading

Smith, Mike, 2013, The Archaeology of Australia’s Deserts, Cambridge University Press