It began like many archaeological discoveries in the Americas: woodcutters working along the banks of Chinchihuapi Creek, a tributary of the Maullín River about 36 miles from the Pacific coast of southern Chile near Puerto Montt, observed the bones of very large animals protruding from an eroded bank.
The investigations that followed, however, beginning in the 1970s at what became known as the Monte Verde archaeological site, revealed more than just the dwelling place of some of Chile’s earliest residents. Findings there, including radiocarbon dates indicating a human presence as early as 14,500 years ago, led to a controversy that shook the foundations of American anthropology, upending past thinking on not only who had been the first to arrive at sites like this one—now a proposed UNESCO World Heritage Site—but more fundamentally, whether people initially migrated into the Americas far earlier than previously ever imagined.
For many years, the debate over whether sites like Monte Verde provided unequivocal evidence that there were people in the New World prior to the appearance of the Clovis culture—long recognized as the oldest confirmed cultural manifestation in the Americas, and dating to no earlier than around 13,500 years ago—remained one of American archaeology’s most challenging questions.
With time, however, and a growing number of similar discoveries at sites in North and South America that would follow, the debate appeared to have been settled: pre-Clovis had become the accepted paradigm, and the scientific data first uncovered by archaeologist Tom Dillehay, Ph.D, at Monte Verde clearly showed it.
However, that doesn’t mean there haven’t been a few holdouts who continue to argue that the once widely accepted “Clovis horizon” may still be closer to the mark, in terms of when the first large-scale migrations into the Americas began. While their numbers have diminished somewhat within the 21st century, some archaeologists like Dr. Todd Surovell, a Professor and Department Head of the Department of Anthropology at the University of Wyoming, have kept the debate alive by challenging what he and a few colleagues view as a kind of new orthodoxy that has slowly emerged out of what was once considered a fringe idea in American archaeology.
Now, as evidenced by a recent study by Surovell and several co-authors published in Science, not only is the debate still burning after many decades, but the enigmatic Monte Verde archaeological site appears to have maintained its place at the center of the controversy.
Controversy Returns to Monte Verde
According to their recent paper, Surovell and his colleagues have presented a rather bold challenge to one of the most influential archaeological discoveries in the Americas, suggesting that Monte Verde could be younger—perhaps by thousands of years—than previously indicated by the data.
Based on new research that marks the first independent investigation of the site in close to half a century, Surovell and his collaborators argue that evidence for a human presence at Monte Verde may date back as early as 8,200 years, or potentially even as recently as 4,200 years.
Surovell and his collaborators based their findings on the premise that older Ice Age wood may have been moved into comparatively younger archaeological layers along Chinchihuapi Creek, potentially explaining how radiocarbon dates indicating an age of 14,500 years could still be found in much later Holocene deposits. This, as well as the identification of an 11,000-year-old layer of volcanic ash, which, the authors argue, appears in an earlier geological context than Monte Verde’s human occupation layer—something that would be expected if people didn’t reach the site until sometime after 11,000 years ago.
“None of the previously dated materials are clearly artifactual, and they occur in a Holocene deposit,” Surovell told The Debrief in an email. “Abundant Pleistocene wood and megafaunal remains would have been available for use and modification by people in the Middle Holocene.”
For Surovell and his colleagues, the materials that underpinned the original scientific dating of Monte Verde do not necessarily indicate that humans were present during the Pleistocene.
“Arguing for human presence based on possibly artifactual Pleistocene organic matter from a Holocene deposit is not a particularly strong basis for arguing that people were deep into the Southern Hemisphere some 1,500 years prior to Clovis,” Surovell said.
Asked whether any younger dates associated with a site like Monte Verde—if confirmed—might impact the broader debate about early human migration into the Americas, Surovell said things get a little more complicated.
“It’s a good question, and I think you will get a wide range of answers depending on who you ask,” Surovell told The Debrief, acknowledging that many archaeologists will still point to other pre-Clovis sites as clear evidence for an earlier occupation.
“My answer is that this finding makes the Clovis first and ice-free corridor hypotheses viable again,” Surovell said, adding that “This is not to say that coastal migration and pre-Clovis are necessarily incorrect, but that a range of colonization scenarios should be under serious consideration once again.”
Monte Verde in the Crosshairs… Again
Given the controversial nature of Surovell’s findings, The Debrief also reached out to Tom Dillehay, Ph.D., whose seminal work at Monte Verde decades ago first brought recognition to the site and, in doing so, helped foment a major controversy in American archaeology. Dillehay is currently the Rebecca Webb Wilson University Distinguished Professor of Anthropology, Religion, and Culture and Distinguished Professor of Anthropology and Latin American Studies, Emeritus, at Vanderbilt University in Nashville.
In an email to The Debrief, Dillehay said he and his colleagues are currently preparing a formal reply, noting that, in his view, there were “many mistakes” in the new analysis.
In an announcement prepared by The Monte Verde Foundation that Dillehay shared with The Debrief, the Foundation argues that the recent study by Surovell and colleagues “contains many methodological and empirical errors, as it bases its interpretations and conclusions on the extrapolation of dates obtained from misinterpreted, non-archaeological stratigraphic deposits that do not correspond to the layers within the site area.”
“The deposits analyzed include layers that are either significantly older or significantly younger than the MV-5 peat layer that overlies, seals, and preserves the site,” the statement continues. “The dates obtained by Surovell et al. are ambiguous and do not correspond to the excavated archaeological record of Monte Verde II, the stratigraphy of which has been documented and published over decades of scientific research.”
“Based on these external contexts, the authors project deductions onto the site using non-comparable geological contexts, leading to incorrect interpretations regarding the chronology and integrity of the archaeological record,” the Foundation’s statement argues.
“The scientific team behind the Monte Verde Project is currently preparing a detailed scientific response that will systematically address the methodological, empirical, and contextual errors present in the [Surovell team’s study],” the Foundation’s statement added.
“Good Science” Behind New Re-Analysis
Offering a contrasting view, in an email to The Debrief, Dr. Ben A. Potter, a professor in the Department of Anthropology at the University of Alaska Fairbanks who specializes in subarctic archaeological sites, said he feels the research by Surovell and his team presents a convincing argument for a more recent human occupation at Monte Verde than previously believed.
“I found the research to be of high scientific standards,” Potter told The Debrief. “Importantly, and this is not always the case in archaeology, multiple hypotheses were formulated, data were collected to specifically address them, and appropriate tests were made. They convincingly demonstrate that the site dates to the middle Holocene, not 14,500 years ago, as the original investigators thought.”
“This is good science,” Potter said.
For Dr. Potter, the new research was convincing because the authors provided multiple lines of evidence. Specifically, elements Potter found most compelling included the volcanic ash layer, which he says offers “a minimum age for the Monte Verde II deposits,” as well as the many thousands of years of overlap between dates from the upper terrace at the site, and the deposits associated with Monte Verde II terrace, which he says would not be expected if the earlier hypothesis of an intact 14,500-year-old cultural surface were accurate.
Apart from the information detailed in the new paper, Potter also notes the absence of other unambiguous human habitation sites in the region.
“After 50 years, there remain zero other sites similar to Monte Verde in the region, and in South America as a whole,” Potter said. “The projectile points are clearly shown to be middle Holocene in age, similar to other well-known sites in the region, also consistent with the geoarchaeological work by Surovell and colleagues.”
Finally, Potter also notes that Monte Verde appears inconsistent with models based on genetic data, which he says “show a rapid, star-like radiation at the onset of colonization.”
“All other cases of this type of modern human expansion leaves traces of numerous sites with homogeneous technology across a vast area,” Potter told The Debrief. “Monte Verde stands in stark contrast to this expectation.”
The Counterargument: A Geo-Archaeologist’s Perspective
Fundamentally, Surovell and his colleagues’ analysis argues that the earlier radiocarbon dates initially retrieved from Monte Verde decades ago may have been influenced by the geological process known as redeposition. In essence, Ice Age wood carried by erosion along the creek became mixed into younger sediment layers that contain artifacts from the site.
The team also identified volcanic ash layers, roughly 11,000 years old, which can be viewed as regional geological markers. If the site truly dated to 14,500 years ago, the researchers argue, ash should appear above the occupation layer. However, based on Surovell’s findings, it does not.
Seeking additional perspectives involving the geological aspects of the new research, The Debrief reached out to Dr. Michael Waters, a Texas A&M University Distinguished Professor and geologist by training, whose expertise includes both archaeological and geoarchaeological investigations.
Based on his review of the geological information conveyed in the new paper, Waters told The Debrief during a video call that he takes issue with several elements of the data Surovell and his colleagues present.
“At best, I would say this is a working hypothesis that is poorly supported by the data,” Waters told The Debrief, calling the geological component of the new research “a very superficial geological study.”
“I don’t think the evidence as presented by Surovell and others actually conclusively demonstrates that this is a Holocene age deposit containing Holocene artifacts,” Waters said. “Dillehay’s explanation and age for the site is just as credible—in fact, more credible.”
Waters pointed to the 11,000-year-old volcanic ash layer the recent study’s authors identified as “the only concrete thing they did,” though adding that “they haven’t supported with evidence that erosion really took place in the Holocene.”
While speaking with The Debrief, Waters explained that he closely examined the radiocarbon record presented in the new paper, focusing on the ages of the wood and ash layers recently identified at the site.
“There are pretty good-sized unconformities in there, and breaks in deposition,” Waters said. “Between the ash and the youngest ages of the wood is a discrepancy of 2,500 years. So, wait a minute, that’s an unconformable sequence—that’s not conformable at all.”
Waters also addressed the presence of paleosols, ancient soils that formed in past environments and that geologists rely on as potentially crucial records of past climates and ecosystems, providing a means of interpreting landscape evolution and climatic changes over geological time.
“Obviously, whoever did the geology knew nothing about buried soils,” Waters said. “You just look at the pictures, and I can see palesols in their sections, which they don’t even describe.”
However, Waters points specifically to the study’s description of the terrace sequence as being what stood out the most to him, telling The Debrief that what he read “stopped me dead in my tracks.” In their paper, Waters notes that the authors report that Terrace 3 at the site “is both an erosional terrace and a depositional terrace.”
“That’s not possible in geology,” Waters explained. “It’s either one or the other, and they’re formed by different processes. They’re still fluvial processes, but they’re formed differently.”
“This is the Achilles heel, right here, of their arguments,” Waters told The Debrief. “They obviously don’t understand geology, or they would have realized that this is a dagger in their own arguments.”
During our call, Waters also discussed the ash layer the team identified, which is visible in imagery of Terrace 3 in portions of the paper that discuss this feature as a depositional terrace. However, when shown in images corresponding to the discussion of being an erosional terrace, Waters said it appears truncated in the study’s imagery.
“That means that Terrace 3 was already cut in the Pleistocene prior to the deposition of that ash,” Waters told The Debrief. “Right there, their argument flies out the window, and this was the first paper I’ve ever seen where you can refute their own story based on reading their paper.”
“They’ve got this ash mat down in these upper deposits. That’s good evidence,” Waters concedes, although he feels the authors assumed that beyond this, “ everything moved down and got deposited in a middle Holocene terrace.”
“I think independent evaluation is good,” Waters also said. “That’s what keeps people honest, and if somebody overlooks something, or there’s new technology available, you should apply it to a site.”
“They have some real data: there’s volcanic ash there that’s 11,000 years old. They got some radiocarbon dates from wood up there on Terrace 4,” Waters concluded, though adding, “that’s as far as you can go.”
A Long-Running and “Rancorous Debate”
The starkly differing views expressed by members of the archaeological community concerning the new assessment of the Monte Verde site highlight the contentious nature of the ongoing debate over the timing of the first arrivals into the Americas—a controversy that is far from new.
In May 2012, an editorial published in Nature offered commentary on the almost peculiar level of volatility associated with the subject, asserting that the “rancorous debate over when people first arrived in America has not helped science.”
“The histories of these arguments are a case study of poor communication and missed opportunities,” one portion of the editorial read, describing a researcher who spoke with Nature that said they had “never before witnessed the level of aggression” accompanying the first Americans debate, particularly coming from those who supported the Clovis-first model.
“Researchers who went against that model by reporting even older sites of human occupation endured brutal criticism from opponents who did not give them, or their evidence, a fair hearing,” the Nature editorial added, noting that pre-Clovis claims were often denounced as simply being poor scholarship, although mounting evidence began to accumulate in the early years of the new millennium supporting the once-controversial theory.
“Credit for this breakthrough should go to open-minded archaeologists, the Nature editorial argued in light of new discoveries, adding that some scientists “should examine their recent behaviour,” accept the possibility they may be wrong, and “look carefully at opposing data and conclusions.”
“Such prescriptions sound obvious, but many scientists forget them, particularly in fields with limited data, such as archaeology,” the Nature editorial added.
Speaking with this author during a 2020 interview, Dr. Dillehay reflected on his own experiences with the long-running pre-Clovis controversy, noting that opinions on the issue seemed to differ particularly between North American archaeologists and those from other nations.
“A tiny group of colleagues still vehemently defends the Clovis first model,” Dillehay said at the time. “I mean, that’s their life.”
“Throughout the course of Monte Verde, I got a lot of support, and not a single element of doubt from Europeans,” Dillehay said during the interview. “South American colleagues bought into it. They came and visited the site while we were excavating. Maybe one or two had some doubts, because they were trained in the U.S.”
“North American colleagues who adhered strongly to the Clovis-first paradigm just gave us hell,” Dillehay recalled, noting that he never graduated any of his Ph.D. students based on work at Monte Verde due to the controversy it once generated.
“I’ve now graduated over 40 Ph.D. students in my career,” Dillehay said. “I would not allow any of them to get near Monte Verde because I knew at the time it would destroy their careers.”
Paradoxically, archaeologists like Dillehay, who had once been at the forefront of what was perceived as a heretical movement, are now viewed by some—including Todd Surovell—as part of a new orthodoxy arising from the nonconformist attitudes of such past archaeological renegades.
In an email to The Debrief, Dr. Surovell emphasized that his and his colleagues’ paper “reports our interpretation of the age and formation of the site based on existing data and the new data we collected,” adding that they “welcome legitimate scientific debate and additional study.”
“I have little interest in engaging in debates concerning politics or arguments from authority,” Surovell added.
Speaking with The Debrief, Dr. Ben Potter noted that the debate over Monte Verde extends beyond how old it may be to, perhaps more importantly, how science based on past interpretations of its age has influenced other archaeological milestones.
“Monte Verde II was the first site to ‘break the Clovis barrier’ and has been very influential in shaping archaeological opinions about the timing of the peopling of the Americas,” Potter said. “Though I note that a survey in 2012 (Wheat 2012) found 67% of archaeologists’ surveys in support of the antiquity of the site, while a substantial 33% either rejected it or were noncommittal.”
Potter argues that many other controversial alleged pre-Clovis sites have been rejected, while others remain somewhat disputed due to unresolved issues. “Monte Verde was considered the strongest in terms of archaeological support.”
For many archaeologists, Potter believes, Monte Verde has remained a cornerstone of progress in South American archaeology and, more broadly, in that of the entire Western Hemisphere for decades.
“[The] presence of humans so far south at 14,500 years ago made an ice-free corridor migration much less likely,” Potter said, “and this has been used to support a coastal model of entry. Even specific genetic models have relied on the site.”
Few would argue that the new research by Surovell and his team has reignited the fire that has long kept Monte Verde a hot topic in American archaeology. Yet beyond the controversy it continues to generate, for archaeologists like Potter, the new research also gives new life to the range of possibilities he feels his colleagues should be exploring.
“This research re-opens the door to multiple hypotheses,” Potter says, “including expansion of Native American ancestors through the terrestrial Ice-Free Corridor.”
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached at micah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.