Landsat Image Gallery
acquired October 21, 2024

Lake Mungo’s Geological and Archaeological Treasures

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The southwest corner of New South Wales, Australia, is a remote, semi-arid desert dotted with sheep pastures, dryland farms, and ample space for kangaroos to graze. But starting around 2 million years ago and through most of the Pleistocene, it hosted a system of large lakes, around which Australia’s First Peoples lived for millennia.

Archaeological evidence indicates that humans arrived in what is now known as the Willandra Lakes Region approximately 50,000 years ago. They would have had access to freshwater mussels, crustaceans, and fish, as well as emus and marsupials. As the climate changed and the ice age drew to a close, the lakes shriveled, became more saline, and ultimately dried up around 18,500 years ago.

This image, acquired on October 21, 2024, by the OLI-2 (Operational Land Imager-2) on Landsat 9, shows the remnant of one of these Pleistocene waterbodies, Lake Mungo. The dry lakebed is distinct for the large lunette dune fringing its eastern shoreline. These types of crescent-shaped mounds form on the downwind side of enclosed desert depressions. The Lake Mungo lunette, built up by the wind over the past 50,000 years, measures approximately 30 kilometers (18 miles) long—large enough to be easily visible from space.

The dune has preserved an array of archaeological and geological treasures. Researchers have noted that all layers of the dune contain archaeological remains, indicating that humans occupied the area through various environmental conditions. In addition, a menagerie of megafaunal remains includes those of the giant marsupial and wombat-relative Zygomaturus trilobus, the large flightless bird Genyornis newtoni, the Tasmanian tiger, and giant kangaroos.

Famously, the remains of “Mungo Lady,” uncovered in the lunette dune in 1968, have been dated at 40,000–42,000 years old. They represent the oldest human remains found in Australia and are among the earliest anatomically modern human remains discovered anywhere in the world. The similarly aged bones of “Mungo Man” were found a few years later. The two skeletons provide some of the earliest evidence of cremation and ritual burial.

Scientists have also turned up clues about our planet’s past at the site. In the 1970s, researchers found evidence for a “geomagnetic excursion” baked into 30,000-year-old hearths preserved there. Excursions are significant changes to the intensity of Earth’s magnetic field and the orientation of its magnetic poles. Whereas complete magnetic pole reversals occur about every 300,000 years on average, excursions may happen 10 times as often and on a regional scale.

Today, the effects of various land management practices are visible as sharp contrasts in color on the semi-arid landscape. “The lines you can see in the images are fence-line boundaries between Mungo National Park and neighboring pastoral properties that mostly graze sheep,” said Mike Letnic, an applied ecologist and conservation biologist at the University of New South Wales.

Wild herbivores such as kangaroos and rabbits, along with domestic animals, graze in the brighter area containing the western portion of Lake Mungo’s lakebed, which is outside of the national park. Within park boundaries, grazing is limited to wild animals. But according to Letnic, grazing pressure on the land is still high because these herbivores have no predators regulating their populations.

NASA Earth Observatory image by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Story by Lindsey Doermann.

This image record originally appeared on the Earth Observatory. Click here to view the full, original record.