The Atacama Desert Had Freshwater Lakes 9,000 Years Ago

The borders of the Atacama Desert extend into Bolivia, where there are lakes and lagoons around today.mezzotint/Shutterstock

Robin Andrews 19 Dec 2016, 10:16

Chile’s Atacama Desert may have had lakes around 9,000 to 25,000 years ago, according to researchers from the University of California, Berkeley. Announcing their findings at the annual meeting of the American Geophysical Union in San Francisco, this implies that humans could once have found the most arid place on Earth fairly suitable to live in.

Organic material belonging to plants and animals that required plentiful supplies of freshwater were found beneath the surface of the sands. Thanks to the high salinity levels and lack of water in the present day, they have been remarkably well preserved over the last few millennia.

Their distribution revealed that, of the desert’s 105,000 square kilometers (41,000 square miles) of arid territory seen today, at least 600 square kilometers (232 square miles) used to contain lakes.

The Atacama Desert is the driest non-polar desert in the world. Stuck between two mountain chains, saturated air cannot effectively reach it, and thus very little precipitation occurs. Within this “rain shadow”, a variety of flora and fauna do exist, but they have to make do with as little as 1 millimeter (0.04 inches) of rain per year.

Curiously, geological evidence points towards these incredibly low precipitation rates being present here for around 2.5 million years. This means that these lakes were not produced by rainfall, but perhaps water that was naturally stored atop the Andes Mountains suddenly draining down onto the plateau.

Archaeologists and anthropologists have long thought that humans in the region actively avoided the harsh conditions of the Atacama. However, this new evidence suggests that they perhaps did not have to avoid the desert entirely as long as they spotted the lakes along their journey.

“The implication is that a landscape previously thought to be uninhabitable was actually an important stepping-stone for colonization of South America,” lead researcher Marco Pfeiffer, a soil scientist at the University of California, Berkeley, told attendees at AGU.

Sundown at the Atacama Desert. kwest/Shutterstock

In fact, because it now seems possible that nomadic travelers could have survived a trek through the Atacama Desert, it is now a place that Pfeiffer thinks has a “rich, early archaeological record remaining to be discovered and analyzed.”

Indeed, some populations were known to have started their civilizations within the Atacama, including many Pre-Columbian societies. The Chinchorro people were one, but they appear to have settled within the desert around 9,000 to 7,000 years ago, shortly after the lakes there would have evaporated away.

These sedentary people were fishermen, and they mostly sustained themselves by living along the coast. They are most famous for mummifying their dead – particularly children and babies – and to date, more than 300 of these preserved humans have been found by archaeologists.

Were the Chinchorro preceded by others as of yet unknown? Watch this space.

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