ISS035-E-9454 Click the photo number to access all resolutions available and the database record.
Strings of narrow lakes that represent ancient rivers are also present in the region. The white feature down the center of the image is Lake Auld; the color is the result of a cemented combination of fine, clayey sediment and salts from the evaporation of flood waters that occasionally fill the lake. Wider views of the area show that Lake Auld is part of what was once a major river system draining northwest to the Indian Ocean. Such sinuous lakes are also known in Australia as “river lakes.” (Other views showing the ancient winding rivers are available here and here.)
The river system is remarkably well preserved, considering that the rivers were probably active in the Paleocene Epoch more than 55 million years ago. At the time, the Australian land mass was much further south, in a wetter climatic zone. Almost all rivers in the Great Sandy Desert are dry in today’s desert climate.
Linear dunes can be seen entering Lake Auld on the east side. During flooding events, the sand of the dune noses is dispersed, becoming incorporated into the muds and salts of the lake floor sediments. During the long, intervening dry periods, sand can blow across the lake floor to build thinner, smaller dunes, visible as linear accumulations on the west side of the lake.
