Marco Pfeiffer and his colleagues discovered that the now-arid Atacama Desert as soon as supported freshwater lakes and wetlands.
Credit score: Marco PfeifferSAN FRANCISCO — The driest desert on Earth might have as soon as been a patchwork of lakes and marshlands that supported the primary settlers of South America as they populated the continent, new analysis suggests.
The brand new findings counsel that the bone-dry Atacama Desert, which now appears virtually as devoid of life because the floor of Mars, might have as soon as been an necessary stopping level within the colonization of the Americas.
Though the Atacama Desert, though it's a barrier these days, it wasn't on the time early individuals have been settling the Americas, Marco Pfeiffer, a doctoral candidate in soil science on the College of California at Berkeley, mentioned right here at a information convention at this time (Dec. 14) on the annual assembly of the American Geophysical Union. [See Photos of the 10 Driest Places on Earth]
A protracted and winding route
Presently, scientists imagine individuals from northern Asia holed up in ice-free refuges within the space across the Bering Strait for hundreds of years, then spilled out into North America between 20,000 and 18,000 years in the past and migrated quickly alongside coastlines to occupy South America. The oldest recognized proof of human occupation in South America was discovered at a Chilean web site south of Atacama known as Monte Verde, which was occupied someday between 14,800 and 18,500 years in the past. Sadly, proof to recreate this early migration is sparse; archaeologists imagine many of the first People traveled alongside the shoreline, which is now submerged beneath 330 ft (100 meters) of water.
In concept, America's first settlers might have additionally fanned out into Chile's Atacama Desertduring this early interval. However the barren moonscape is likely one of the most forbidding locations on the planet.
Squished between two mountain ranges that block rainfall from either side, the 600-mile-long (1,000 kilometer) expanse will get simply zero.6 inches (15 millimeters) of rainfall a yr. The hyperarid situations produce a salty, cracked crust that at this time helps virtually no plants. [See Images of the Arid Atacama Desert In Bloom]
As a result of archaeologists assumed the world was too menacing for early human settlers to have occupied for lengthy, nobody bothered in search of proof of historical settlements. Just a few research have prompt that between 7,000 and 9,000 years in the past rainfall in some areas of the Atacama might have been as much as six instances the present ranges.
Then, in 2013, researchers printed a examine within the journal Quaternary Science Reviewsrevealing one thing extraordinary: proof of human occupation at a web site within the bone-dry coronary heart of the desert, courting to round 13,000 years in the past, Pfeiffer mentioned.
"The one approach this web site might have occurred is that there was a stream close by that may provide water to this human settlement," Pfeiffer mentioned.
The place there's water, there's life, however the reverse can be true. So Pfeiffer and his colleagues appeared for proof of water within the desert. Quickly, they discovered it: Buried beneath a thick salt crust, they found proof of historical crops and animals, equivalent to gastropods and phytoliths (tiny buildings present in some plant tissues), that are usually present in freshwater lakes. Courting strategies utilizing isotopes of carbon, or variations of carbon with totally different numbers of neutrons, revealed that the areas have been moist someday between 17,000 and 9,000 years in the past.
The brand new information counsel the Atacama was as soon as lined with a sequence of wetlands and marshes, together with marshlands peppered with grasses and sedges that will have supported historical camelid species (equivalent to vicuna and guanaco) in addition to different now-extinct mammals, Pfeiffer mentioned. These, in flip, would have supplied sustenance for an early inhabitants of hunter-gatherers, he mentioned.
They've additionally discovered some hints of early human occupation within the area, although the websites have but to be excavated and no outcomes have been printed in a peer-reviewed journal, Pfeiffer mentioned.
Authentic article on Reside Science.
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