By Will Dunham
Aug 31 (Reuters) – Two groups of researchers are defending the view that the Monte Verde archaeological site in Chile was occupied by ancient hunter-gatherers about 14,500 years ago after another study indicated it was much younger — a debate with major implications for understanding the initial peopling of the Americas.
This creek valley site, located in southern Chile about 36 miles (58 km) from the Pacific coast, was discovered in the 1970s. The scientific testing announced in 1997 that concluded that people were present at this locale deep in South America about 14,500 years ago suggested a much earlier arrival for humans in the New World than had been believed at the time.
But a study published in March based on different testing called that into question, concluding that Monte Verde dated to between about 4,200 and 8,200 years ago.
Now, the site’s research team and another group of scientists have identified in analyses appearing in the journal PaleoAmerica what they consider fundamental flaws with that study, which was published in the journal Science.
“They did not demonstrate that the original geological interpretation of the site was in error,” said Vanderbilt University anthropologist Tom Dillehay, who has studied Monte Verde extensively since the 1970s and led one of the analyses.
“I remain confident in our methodology and results,” said University of Wyoming archaeologist Todd Surovell, who was the lead author of the research that suggested a younger age for the site — a finding that, if correct, would make Monte Verde irrelevant to the investigation of when people first spread through the Americas.
The older age would place Monte Verde more than 1,500 years before the previous earliest-known human occupation sites south of the continental ice sheets that covered parts of North America at the time. Those Ice Age sites were associated with North America’s Clovis culture, known for distinctive stone tools and named for a locale in New Mexico.
Because Monte Verde was considered older and was thousands of miles south of the Clovis locations, scientists viewed it as evidence that people must have trekked into the Americas from Eurasia much earlier than the Clovis sites had indicated.
Dillehay faulted evidence presented by Surovell and colleagues as not arising from observations directly at the site where the archaeological evidence was found but instead from geology outside it.
An important element of the paper in Science was the description of a layer of volcanic ash deposited about 11,000 years ago that is situated below the archaeological evidence of occupation, which would show that the human presence at Monte Verde was more recent than that date.
“That was never observed by all investigators working at Monte Verde since 1977,” Dillehay said of an ash layer.
Dillehay took issue with other aspects of the Science paper, and said he believes those researchers cherry-picked geological evidence to “fit a predetermined conclusion.”
‘A GREAT DEAL OF SCRUTINY’
Surovell said he welcomes continued scientific debate about the age of Monte Verde and the processes responsible for its formation. The best way to resolve these questions, Surovell said, is through additional study by independent researchers.
“Our work has now received a great deal of scrutiny, which is exactly what should happen with a claim this important. If there were major problems with our methods, data or reasoning, I would have expected them to become apparent through that process. So far, I have not seen criticisms that I think undermine the central conclusions of our study,” Surovell said.
Dillehay underscored the archaeological importance of the site.
“Monte Verde’s exceptional preservation has made it possible to recover materials rarely found in the archaeological record, including worked wood, remains of structures, plants, seaweed, and other organic materials, offering an extraordinary window into the life and knowledge of the human communities that inhabited southern Chile during the late Pleistocene,” Dillehay said, referring to the geological timeframe spanning the last Ice Age.
Also found at the site were human footprints associated with a hearth, remains of fires, wooden tools and stakes, as well as remains of potatoes and animal bones and flesh.
“Monte Verde is well sealed by an anaerobic peat layer that preserved organics at the site, so we have a much more in-depth notion of the technology and especially the economy of people at that time. They were broad-spectrum consumers who lived on both plants and animals, and foraged from the Pacific coast to the Andean mountains,” Dillehay said.
(Reporting by Will Dunham in Washington; Editing by Daniel Wallis)
