Rejecting the Solutrean hypothesis: the first peoples in the Americas were not from Europe

A recent Canadian documentary promoted a fringe idea in American archaeology thats both scientifically wrong and racist

Last month’s release of The Ice Bridge, an episode in the Canadian Broadcasting Corporation series The Nature of Things has once again resurrected public discussion of a controversial idea about how the Americas were peopled known as the “Solutrean hypothesis”. This idea indicates a European origin for the peoples who built the Clovis tools, the first recognized stone tool tradition in the Americas. As I was one of the experts appearing on the documentary, I want to share my guess about it and why I watch the ideas portrayed within as unsettling, unwise, and scientifically implausible.

First, in addition to the scientific problems with the Solutrean hypothesis which I’ll discuss shortly, it’s important to note that it has overt political and cultural implications in denying that Native Americans are the only indigenous peoples of the continents. The notion that the ancestors of Native Americans were not the first or only people on the continent has great popularity among white patriots, who see it as an instrument of denying Native Americans an ancestral claim on their land. Indeed, although this particular iteration is new, the idea behind the Solutrean hypothesis is part of a long tradition of Europeans trying to insert themselves into American prehistory; justifying colonialism by claiming that Native Americans were not capable of creating the diverse and sophisticated material culture of the Americas. Regrettably, the producers of the documentary deliberately chose not to address this issue head-on , nor did they include any critical perspectives from indigenous peoples. While supporting the agenda of white patriots was not the purposes of applying the producers or of the scientists involved, it would have been appropriate for the documentary to take a stand against it, and I and many archaeologists are disappointed that they did not.

Bruce Bradley and Dennis Stanford, proponents of the Solutrean hypothesis, base it on the claim that the North American Clovis stone spear phases are the technological descendants of a subset of those made by the Upper Paleolithic southwestern European Solutrean peoples. Specifically they quote fact that both are made by a technique known as “overshot” flaking as evidence for their common origin. From this starting point, Bradley and Stanford propose a hyperdiffusionist scenario in which a group of Solutreans migrated across the Atlantic Ocean to Northern america via an “ice bridge” approximately 20,000 years before present( YBP ). Although they don’t deny that the majority of Native American ancestry comes from a group of Siberians who lived in Beringiaduring the Last Glacial Maximum (~ 23,000 YBP-1 3,000 YBP ), they claim that “great numbers” of Solutreans must also have migrated to North America.

Solutrean tools 22000 -1 7000 Crot du Charnier Solutre Pouilly Saone et Loire France Photograph: By World Imaging[ CC BY-SA 3.0( https :// licenses/ by-sa/ 3.0) or GFDL( http :// copyleft/ fdl.html )], via Wikimedia Commons

Archaeologists have taken a hard, long look at this idea and rejected it on the basis of insufficient evidence. The mismatch between the archaeological record and the Solutrean hypothesis is so extensive that I can’t cover every problem, but here is a sample 😛 TAGEND

1. There’s a serious time gap between when the Solutreans could have crossed the Atlantic via the ice bridge (~ 20,000 YBP) and when Clovis tools begin to show up in the archaeological record (~ 13,000 YBP ). This means that they would have attained the points in exactly the same way for 7,000 years. Nowhere else in the Americas do we see technologies and cultures existing unchanging for that length of time.

2. There is no evidence of boat use, or tools used for making barges at Solutrean sites. Although the Ice Bridge documentary makes much of an image of a fish and an auk in a French cave, it is a bit of a stretch( to say the least !) to assert that this is sufficient to demonstrate a sophisticated seafaring culture, capable of traversing the Atlantic. The existence of a year-round “ice bridge” across the Atlantic during the Last Glacial Maximum is not supported by paleoclimate data. Instead, sea ice in the Atlantic would most likely have been seasonal, with a connection between North American and Europe only a few months out of the year.

3. The notion of overshot flaking technique as evidence of a link between Clovis and Solutrean has been called into question by many archaeologists, who think it far more plausible that the two cultures arrived at the same technology independently. As Strauss( 2000 )~ ATAGEND puts it,” One or two technical attributes are insufficient to establish a culture connection or long-distance interconnection .”

4. Radiocarbon dates of Clovis sites do not show a pattern one is looking forward to if people diffused into Northern america from the east coast, as postulated by Stanford and Bradley.

Geneticists, too, have tested the Solutrean hypothesis. If it were true, we would expect to see ancestry from non-Siberian descended populations present in the genomes of ancient Native Americans. We don’t. All contemporary and ancient Native Americans, including the only known ancient individual buried in association with Clovis tools, indicate descent from an ancestral population with Siberian roots. There is a very clear pattern of evolutionary history recorded in ancient genomes from Siberia, Beringia, and North America, and no proof for trans-Atlantic gene flow.

This is where the Ice Bridge documentary operates into great problems. It ignores all genomic proof and instead relies upon an old notion that a particular mitochondrial haplogroup( a group of closely related maternal pedigrees) known as X shows a connection between North America and Europe. In the documentary, pediatrician/ popular science writer Stephen Oppenheimer asserts that the presence of haplogroup X in an ancient North American population is a priori proof for a European connection. The documentary builds this case persuasively with graphics and maps presenting the presence of this haplogroup in both Europe and Northern america. But seem below the surface and the entire debate falls apart. First of all, Standford, Bradley, and Oppenheimer simply assume that Solutreans would have had X because it’s seen in contemporary European populations. But in fact, the contemporary European gene pond was formed merely within the last 8,000 years, and it’s unknown whether earlier people would have had haplogroup X in the same frequencies( or at all ). No genomes from Solutren peoples have ever been sequenced, and you should always be cautious when a case is constructed for extending present day patterns of genetic difference into the past without direct verification from ancient DNA.

Today, lineages of haplogroup X are procured widely dispersed throughout Europe, Asia, North Africa, and Northern america. We can reconstruct their evolutionary relationships- much like you can rebuild a family tree- by looking at patterns of shared and derived mutants. Lineages found in the Americas, X2a and X2g, are not descended from the lineages( X2b, X2d, and X2c) found in Europe. Instead, they share a very ancient common ancestor from Eurasia, X2.( Here is a detailed discussion of the evolution of these haplogroups for anyone interested ).

X2a is of a comparable age to other indigenous American haplogroups( A, B, C, D ), which would not be true if it was derived from a separate migration from Europe. Finally, the oldest lineage of X2a found in the Americas was recovered from the Ancient One( also known as Kennewick Man ), an ancient individual dating to~ 9,000 years ago and from the West Coast( not the Eastern coast as would be predicted from the Solutrean hypothesis ). His entire genome has been sequenced and shows that he has no ancestry from European sources. There is no conceivable scenario under which Kennewick Man could have inherited simply his mitochondrial genome from Solutreans but the rest of his genome from Beringians. Thus, without additional proof, there is nothing to justify the assumption that X2a must have evolved in Europe.

The Ice Bridge regrettably relied on cherry-picking of data to support the ideas of Bradley and Stanford, and it’s not up to the standards of The Nature of Things . When I write about this issue, I often hear an debate along the lines of” Well, it could have happened, so maybe it did “. But science isn’t built on “could haves” and “maybes”. You must construct your models based on evidence you have , not evidence you wish you had, and the Solutrean hypothesis is lacking sufficient evidence to be considered severely.

References and further reading

Raff J, and Bolnick D.( 2015) Does Mitochondrial Haplogroup X Indicate Ancient Trans-Atlantic Migration to the Americas? A Critical Re-Evaluation.

O’Brien, Michael J ., Matthew T. Boulanger, Mark Collard, Briggs Buchanan, Lia Tarle, Lawrence G. Straus and Metin I. Eren( 2014 ). ” On thin ice: problems with Stanford and Bradley’s proposed Solutrean colonisation of Northern america “. Antiquity. 88: 606-624.

Stanford, Dennis J.& Bruce Bradley( 2012 ). Across Atlantic Ice: The Origin of America’s Clovis Culture. Berkeley: University of California Press.

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