People roamed tip of South America 18,500 years ago

Stone tools and charred animal bones from Monte Verde help to rewrite human history in the New World

stone tool from Monte Verde

AMERICAN MADE  A 18,500- to 17,000-year-old stone artifact unearthed at Chile’s Monte Verde site, shown from the side (left) and top (right), contains smooth areas where pieces of the rock were struck off to create a scraping or cutting tool. Researchers say humans first visited the site at least 18,500 years ago.

T. Dillehay

Human groups foraged near the bottom of South America between at least 18,500 and 14,500 years ago, researchers say. Their new discoveries challenge a popular view in archaeology that people entered South America no earlier than 15,000 years ago.

Excavations in southern Chile indicate that ancient human groups sporadically passed through that area over a 4,000-year stretch, say archaeologist Tom Dillehay of Vanderbilt University in Nashville and colleagues. Discoveries near the previously explored Monte Verde site add to evidence that the earliest New World settlers were not members of the Clovis culture, the investigators report November 18 in PLOS ONE. Clovis people hunted big game with distinctive spearpoints and camped at sites with large hearths. Clovis sites date to as early as 13,390 years ago in what is now the United States and Mexico (SN: 8/9/14, p. 7).

Long before that, ancient foragers intermittently stopped at Monte Verde, Dillehay suspects. Work at Monte Verde in the 1970s and 1980s yielded stone tools and other remains of a campsite from around 14,500 years ago. New finds include 39 stone artifacts, nine dating to between at least 18,500 and 17,000 years ago. About one-third of these stones consist of rock found outside the Monte Verde vicinity, either near the Pacific coast or further inland. Early South Americans acquired various types of tool-appropriate rock as they trekked across the landscape and may have traded for some types of rock with other human groups, Dillehay proposes.

ANCIENT EDGES The oldest evidence of humans at Monte Verde comes from stone artifacts dating to between at least 16,000 and 15,000 years ago, including this piece of rock with sharpened edges for scraping or cutting. T. Dillehay
Most of these intentionally modified rocks were used for scraping and cutting, the researchers say. A few circular stones were possibly flung at prey with slings. Artifacts also included sharp fragments of stone produced as by-products of toolmaking.

Four stone artifacts were found in soil dating to at least 25,000 years ago. But more evidence is needed to confirm that humans visited Monte Verde and other South American sites before 20,000 years ago (SN: 4/20/13, p. 9), the scientists say.

Dillehay’s team also identified 12 soil sections containing ash from small fires, bits of burned wood and nine partial animal bones, five of which were burned or showed signs of heating. The estimated ages for the Monte Verde discoveries come from radiocarbon measures of burned material and soil analyses that estimate when artifacts were buried.

Archaeologists searching for further pre-Clovis sites will need to keep an eye out for simple tools and remnants of small hearths or campfires, Dillehay adds. Remains of Clovis sites, which typically feature separate areas for cooking, toolmaking and other activities, are easier to spot.

The discoveries at Monte Verde “point to a new kind of site that needs much more study” to understand when people first reached the Americas, remarks archaeologist Daniel Sandweiss of the University of Maine in Orono. 

Editor’s Note: This story was updated December 7, 2015, to correct the dates of the artifacts shown in the images, and December 9, 2015, to clarify the positioning of the stones in top image.

Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeology and mental health issues.

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