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The theory known as "Clovis First" was the predominant hypothesis among archaeologists in the second half of the 20th century to explain the peopling of the Americas. According to Clovis First, the people associated with the Clovis culture were the first inhabitants of the Americas. This hypothesis came to be challenged by ongoing studies that suggest pre-Clovis human occupation of the Americas. [1] In 2011, following the excavation of an occupation site at Buttermilk Creek, Texas, a group of scientists identified the existence "of an occupation older than Clovis." [2] [3] At the site in Buttermilk, archaeologists discovered evidence of hunter-gatherer group living and the making of projectile spear points, blades, choppers, and other stone tools. The tools found were made from a local chert and could be dated back to as early as 15,000 years ago. [3]
The primary support for this claim was that no solid evidence of pre-Clovis human habitation had been found. According to the standard accepted theory, the Clovis people crossed the Beringia land bridge over the Bering Strait from Siberia to Alaska during the ice age when there was a period of lowered sea levels, then made their way southward through an ice-free corridor east of the Rocky Mountains, located in present-day Western Canada, as the glaciers retreated. [4]
According to researchers Michael Waters and Thomas Stafford of Texas A&M University, new radiocarbon dates place Clovis remains from the continental United States in a shorter time window beginning 450 years later than the previously accepted threshold (13,200 to 12,900 BP). [5]
Since the early 2010s, the scientific consensus has changed to acknowledge the presence of pre-Clovis cultures in the Americas, ending the "Clovis first" consensus. [6] [7] [8]
There have been a great number of archaeological findings across the Americas that pre-date the arrival of humans prior to 11,500–11,000 uncalibrated years before present (YBP). The Buttermilk Creek Complex, located in Salado, Texas, is a site where over 15,000 artifacts have been found. These artifacts are composed of a variety of small stone tool assemblages. These artifacts stratigraphically underlie previously excavated Clovis assemblages, meaning that they were deposited prior to the Clovis artifacts. These pre-Clovis assemblages are dated to between 13,200 and 15,500 years ago. [9]
Predecessors of the Clovis people may have migrated south along the North American coastlines, although arguments exist for many migrations along several different routes. [10] Radiocarbon dating of the Monte Verde site in Chile places Clovis-like culture there as early as 18,500 to 14,500 years ago. [11] Remains found at the Channel Islands of California place coastal Paleoindians there 12,500 years ago. This suggests that the Paleoindian migration could have spread more quickly along the Pacific coastline, proceeding south, and that populations that settled along that route could have then begun migrations eastward into the continent.
The Pedra Furada sites in Brazil include a collection of rock shelters, which were used for thousands of years by diverse human populations. The first excavations yielded artifacts with carbon-14 dates of 48,000 to 32,000 years BP. Repeated analyses have confirmed this dating, carrying the range of dates up to 60,000 BP. [12] Among the best analyzed archaeological levels are those dated between 32,160 ± 1000 years BP and 17,000 ± 400 BP. These claims have become an issue of contention between North American archaeologists and their South American and European counterparts, who disagree on whether it is conclusively proven to be an older human site. [13] [14] [15]
In 2004, worked stone tools were found at Topper in South Carolina that have been dated by radiocarbon techniques possibly to 50,000 years ago. [16] But, there is significant scholarly dispute regarding these dates. [17] Scholars agree that evidence of humans at the Topper Site date back to 22,900 cal yr BP. [18]
A more substantiated claim is that of Paisley Caves in Oregon, where rigorous carbon-14 and genetic testing appear to indicate that humans related to modern Native Americans were present in the caves over 1000 14C years before the earliest evidence of Clovis. [19] Traces and tools made by another people, the "Western Stemmed" tradition, were documented. [20] [21]
A study published in Science presents strong evidence that humans occupied sites in Monte Verde in Chile, at the southern tip of South America, as early as 13,000 years ago. [22] If this is true, then humans may have entered North America long before the Clovis culture, perhaps as long as 16,000 years ago.
The Tlapacoya site in Mexico is on the base of a remnant volcanic hill on the shore of the former Lake Chalco. Seventeen excavations along the base of Tlapacoya Hill between 1956 and 1973 uncovered piles of disarticulated bones of bear and deer that appeared to have been butchered, plus 2,500 flakes and blades presumably from the butchering activities, plus one unfluted spear point. All were found in the same stratum containing three circular hearths filled with charcoal and ash. Bones of many other animal species were also present, including horses and migratory waterfowl. Two uncalibrated radiocarbon dates on carbon from the hearths came in around 24,000 and 22,000 years ago. [23] At another location, a prismatic microblade of obsidian was found in association with a tree trunk radiocarbon dated (uncalibrated) at roughly 24,000 years ago. This obsidian blade has recently been hydration dated by Joaquín García-Bárcena to 22,000 years ago. The hydration results were published in a seminal article that deals with the evidence for pre-Clovis habitation of Mexico. [24]
Other sites, like White Sands National Park in New Mexico, also demonstrate archaeological findings that predate Clovis populations. In White Sands, excavated surfaces uncovered multiple in situ human footprints that were stratigraphically located between layers of material that were radio carbon dated to be from between 21,000 and 23,000 years ago. The findings from this site predate previous theories about the timeline of human migration of the Americas by several thousand years. Archaeologist working on the site believe that their findings indicates that humans had been present in the region since 23,000 years prior. This would mean that humans were occupying North America during the Last Glacial Maximum (LGM) – a theory that had previously been dismissed. [25]
Though it is not currently the widely-accepted theory, these archaeological sites support alternative theories of early human migration such as a coastal migration route or the Solutrean hypothesis. This archaeological evidence is also supported by genetic mapping of ancestral mitochondrial DNA.
Archaeological sites that predate Clovis that are well documented include:
Studies of the mitochondrial DNA of First Nations/Native Americans published in 2007 suggest that the people of the New World may have diverged genetically from Siberians as early as 20,000 years ago, far earlier than the standard theory suggests. [1] According to one alternative theory, the Pacific coast of North America may have been free of ice, allowing the first peoples in North America to come down this route prior to the formation of the ice-free corridor in the continental interior. [40] No evidence has yet been found to support this hypothesis[ citation needed ] except that genetic analysis of coastal marine life indicates diverse fauna persisting in refugia throughout the Pleistocene ice ages along the coasts of Alaska and British Columbia; these refugia include common food sources of coastal aboriginal peoples, suggesting that a migration along the coastline was feasible at the time. [41] Some early sites on the coast, for example Namu, British Columbia, exhibit maritime focus on foods from an early point with substantial cultural continuity. [42]
This lack of evidence is likely due to the change in sea level since the time of migration. During the Last Glacial Maximum the global sea level was more than 400 feet lower than it is today. Starting about 15,000 years ago, glaciers began retreating and sea levels began rising. Sea levels reached their current level about 8,000 years ago and have fluctuated slightly since then. [43] This drastic change in sea level may prevent the discovery of sites located along what was once the coastline and is now located under over 400 feet of water. As of now, genetic analysis is one of the only means of tracking early human movements.
In February 2014, researchers reported on their DNA analysis of the remains of Anzick boy (referred to as Anzick-1) of Montana, the oldest skeleton found in the Americas and dated to 12,600 years ago. They found the mtDNA to be D4h3a, "one of the rare lineages associated with Native Americans." [44] This was the same as the mtDNA associated with current coastal populations in North and South America. The study team suggest that finding this genetic evidence so far inland shows that "current distribution of genetic markers are not necessarily indicative of the movement or distribution of peoples in the past." [44] The Y haplotype was found to be Q-L54*(xM3). Further testing found that Anzick-1 was most closely related to Native American populations (see below). [44]
The controversial Solutrean hypothesis proposed in 1999 by Smithsonian archaeologist Dennis Stanford and colleague Bruce Bradley (Stanford and Bradley 2002), suggests that the Clovis people could have inherited technology from the Solutrean people who lived in southern Europe 21,000–15,000 years ago, and who created the first Stone Age artwork in present-day southern France. [45] The link is suggested by the similarity in technology between the projectile points of the Solutreans and those found at Clovis (and pre-Clovis) sites. Its proponents point to tools found at various pre-Clovis sites in eastern North America (particularly in the Chesapeake Bay region) as progenitors of Clovis-style tools. [46] The model envisions these people making the crossing in small watercraft via the edge of the pack ice in the North Atlantic Ocean that then extended to the Atlantic coast of France, using skills similar to those of the modern Inuit, making landfall somewhere around the then-exposed Grand Banks of the North American continental shelf.
In a 2008 study of the relevant paleoceanographic data, Kieran Westley and Justin Dix concluded that "it is clear from the paleoceanographic and paleo-environmental data that the Last Glacial Maximum (LGM) North Atlantic does not fit the descriptions provided by the proponents of the Solutrean Atlantic Hypothesis. Although ice use and sea mammal hunting may have been important in other contexts, in this instance, the conditions militate against an ice-edge-following, maritime-adapted European population reaching the Americas." [47]
University of New Mexico anthropologist Lawrence G. Straus, a primary critic of the Solutrean hypothesis, points to the theoretical difficulty of the ocean crossing, a lack of Solutrean-specific features in pre-Clovis artifacts, as well as the lack of art (such as that found at Lascaux in France) among the Clovis people, as major deficiencies in the Solutrean hypothesis. The 3,000 to 5,000 radiocarbon year gap between the Solutrean period of France and Spain and the Clovis of the New World also makes such a connection problematic. [48] In response, Bradley and Stanford contend that it was "a very specific subset of the Solutrean who formed the parent group that adapted to a maritime environment and eventually made it across the north Atlantic ice-front to colonize the east coast of the Americas" and that this group may not have shared all Solutrean cultural traits. [49]
Mitochondrial DNA analysis in 2014 found that members of some native North American tribes have a maternal ancestry (called haplogroup X) linked to the maternal ancestors of some present-day individuals in western Asia and Europe, albeit distantly. This has also provided some support for pre-Clovis models. More specifically, a variant of mitochondrial DNA called X2a found in many Native Americans has been traced to western Eurasia, while not being found in eastern Eurasia. [50]
Mitochondrial DNA analysis of Anzick-1 concluded that the boy belonged to what is known as haplogroup or lineage D4h3a. This finding is important because the D4h3a line is considered to be a lineage "founder", belonging to the first people to reach the Americas. Although rare in most of today's Native Americans in the US and Canada, D4h3a genes are more common among native peoples of South America, far from the site in Montana where Anzick-1 was buried. This suggests a greater genetic complexity among Native Americans than previously thought, including an early divergence in the genetic lineage 13,000 years ago. One theory suggests that after crossing into North America from Siberia, a group of the first Americans, with the lineage D4h3a, moved south along the Pacific coast and, over thousands of years, into Central and South America, while others may have moved inland, east of the Rocky Mountains. [44] The apparent early divergence between North American and Central plus South American populations may or may not be associated with post-divergence gene flow from a more basal population into North America; however, analysis of published DNA sequences for 19 Siberian populations does not favor the latter scenario. [44]
Spearheads and DNA found at the Paisley Caves site in Oregon suggest that North America was colonized by more than one culture, and that the Clovis culture was not the first. There is evidence to suggest an east/west dichotomy, with the Clovis culture located to the east. [51]
But in 2014, the autosomal DNA of a 12,500+-year-old infant from Montana was sequenced. [44] [52] [53] [54] The DNA was taken from a skeleton referred to as Anzick-1, found in close association with several Clovis artifacts. Comparisons indicate strong affinities with DNA from Siberian sites, and virtually rule out close affinity with European sources (the "Solutrean hypothesis"). The DNA shows strong affinities with all existing Native American populations, which indicated that each of them derives from an ancient population that lived in or near Siberia, the Upper Palaeolithic Mal'ta population. Mal'ta belonged to Y-DNA haplogroup R and mitochrondrial macrohaplogroup U. [44] [55]
The data indicate that Anzick-1 is from a population directly ancestral to present South American and Central American Native American populations. This rules out hypotheses which posit that invasions subsequent to the Clovis culture overwhelmed or assimilated previous migrants into the Americas. Anzick-1 is less closely related to present North American Native American populations (including a Yaqui genetic sample), suggesting that the North American populations are basal to Anzick-1 and Central and South American populations. [44] The apparent early divergence between North American and Central plus South American populations might be due to post-divergence gene flow from a more basal population into North America; however, analysis of published DNA sequences of 19 Siberian populations do not suggest this scenario. [44] Anzick-1 belonged to Y-haplogroup Q-L54(xM3), [44] which is by far the largest haplogroup among Native Americans.
The issue is complicated by the discovery that there was DNA backflow from North America to North Asia during the period in question. [56]
Although there is no archaeological evidence that can be used to directly support a coastal migration route during the Last Glacial Maximum, genetic analysis has been used to support this thesis. In addition to human genetic lineage, megafaunal DNA lineage can be used to trace movements of megafauna – large mammalian – as well as the early human groups who hunted them.
Bison, a type of megafauna, have been identified as an ideal candidate for the tracing of human migrations out of Europe because of both their abundance in North America as well as being one of the first megafauna for which ancient DNA was used to trace patterns of population movement. Unlike other types of fauna that moved between the Americas and Eurasia (mammoths, horses, and lions), Bison survived the North American extinction event that occurred at the end of the Pleistocene. Their genome, however, contains evidence of a bottleneck – something that can be used to test hypothesis on migrations between the two continents. [57] Early human groups were largely nomadic, relying on following food sources for survival. Mobility was part of what made humans successful. As nomadic groups, early humans likely followed the food from Eurasia to the Americas – part of the reason why tracing megafaunal DNA is so helpful for garnering insight to these migratory patterns. [58]
The grey wolf originated in the Americas and migrated into Eurasia prior to the Last Glacial Maximum – during which it was believed that remaining populations of the grey wolf residing in North America faced extinction and were isolated from the rest of the population. This, however, may not be the case. Radiocarbon dating of ancient grey wolf remains found in permafrost deposits in Alaska show a continuous exchange of population from 12,500 radiocarbon years BP to beyond radiocarbon dating capabilities. This indicates that there was viable passage for grey wolf populations to exchange between the two continents. [59]
These faunas' ability to exchange populations during the period of the Last Glacial Maximum along with genetic evidence found from early human remains in the Americas provides evidence to support pre-Clovis migrations into the Americas.
Other sites include (in approximate reverse chronological order):
The Solutrean industry is a relatively advanced flint tool-making style of the Upper Paleolithic of the Final Gravettian, from around 22,000 to 17,000 BP. Solutrean sites have been found in modern-day France, Spain and Portugal.
Clovis points are the characteristically fluted projectile points associated with the New World Clovis culture, a prehistoric Paleo-American culture. They are present in dense concentrations across much of North America and they are largely restricted to the north of South America. There are slight differences in points found in the Eastern United States bringing them to sometimes be called "Clovis-like". Clovis points date to the Early Paleoindian period, with all known points dating from roughly 13,400–12,700 years ago. As an example, Clovis remains at the Murry Springs Site date to around 12,900 calendar years ago. Clovis fluted points are named after the city of Clovis, New Mexico, where examples were first found in 1929 by Ridgely Whiteman.
The Clovis culture is an archaeological culture from the Paleoindian period of North America, spanning around 13,050 to 12,750 years Before Present (BP). The type site is Blackwater Draw locality No. 1 near Clovis, New Mexico, where stone tools were found alongside the remains of Columbian mammoths in 1929. Clovis sites have been found across North America. The most distinctive part of the Clovis culture toolkit are Clovis points, which are projectile points with a fluted, lanceolate shape. Clovis points are typically large, sometimes exceeding 10 centimetres (3.9 in) in length. These points were multifunctional, also serving as cutting tools. Other stone tools used by the Clovis culture include knives, scrapers, and bifacial tools, with bone tools including beveled rods and shaft wrenches, with possible ivory points also being identified. Hides, wood, and natural fibers may also have been utilized, though no direct evidence of this has been preserved. Clovis artifacts are often found grouped together in caches where they had been stored for later retrieval, and over 20 Clovis caches have been identified.
Monte Verde is a Paleolithic archaeological site in the Llanquihue Province in southern Chile, located near Puerto Montt, Los Lagos Region. The site is primarily known for Monte Verde II, dating to approximately 14,550-14,500 calibrated years Before Present (BP). The Monte Verde II site has been considered key evidence showing that the human settlement of the Americas pre-dates the Clovis culture by at least 1,000 years. This contradicts the previously accepted "Clovis first" model which holds that settlement of the Americas began after 13,500 cal BP. The Monte Verde findings were initially dismissed by most of the scientific community, but the evidence then became more accepted in archaeological circles. The site also contains an older, much more controversial layer suggested to date to 18,500 cal BP, that lacks the general acceptance of Monte Verde II.
The Upper Paleolithic is the third and last subdivision of the Paleolithic or Old Stone Age. Very broadly, it dates to between 50,000 and 12,000 years ago, according to some theories coinciding with the appearance of behavioral modernity in early modern humans, until the advent of the Neolithic Revolution and agriculture.
Topper is an archaeological site located along the Savannah River in Allendale County, South Carolina, United States. It is noted as a location of artifacts which some archaeologists believe to indicate human habitation of the New World earlier than the Clovis culture. The latter were previously believed to be the first people in North America.
Paleo-Indians were the first peoples who entered and subsequently inhabited the Americas towards the end of the Late Pleistocene period. The prefix paleo- comes from the Ancient Greek adjective: παλαιός, romanized: palaiós, lit. 'old; ancient'. The term Paleo-Indians applies specifically to the lithic period in the Western Hemisphere and is distinct from the term Paleolithic.
The Page–Ladson archaeological and paleontological site (8JE591) is a deep sinkhole in the bed of the karstic Aucilla River that has stratified deposits of late Pleistocene and early Holocene animal bones and human artifacts. The site was the first pre-Clovis site discovered in southeastern North America; radiocarbon evidence suggests that the site dates from 14,200 to 14,550 BP. These dates are roughly 1,000 to 1,500 years before the advent of the Clovis culture. Early dates for Page–Ladson challenge theories that humans quickly decimated large game populations in the area once they arrived.
Cactus Hill is an archaeological site in southeastern Virginia, United States, located on sand dunes above the Nottoway River about 45 miles south of Richmond. The site receives its name from the prickly pear cacti that can be found growing abundantly on-site in the sandy soil. Cactus Hill may be one of the oldest archaeological sites in the Americas. If proven to have been inhabited 16,000 to 20,000 years ago, it would provide supporting evidence for pre-Clovis occupation of the Americas. The site has yielded multiple levels of prehistoric inhabitance with two discrete levels of early Paleo-Indian activity.
The Solutrean hypothesis on the peopling of the Americas is the claim that the earliest human migration to the Americas began from Europe during the Solutrean Period, with Europeans traveling along pack ice in the Atlantic Ocean. This hypothesis contrasts with the mainstream academic narrative that the Americas were populated first by people crossing the Bering Strait to Alaska by foot on what was land during the Last Glacial Period or by following the Pacific coastline from Asia to America by boat.
Pedra Furada is an important collection of over 800 archaeological sites in the state of Piauí, Brazil. These include hundreds of rock paintings dating from circa 12,000 years before present. More importantly, charcoal from very ancient fires and stone shards that may be interpreted as tools found at the location were dated from 48,000 to 32,000 years before present, suggesting the possibility of a human presence tens of thousand of years prior to the arrival of the Clovis people in North America.
Paleolithic Europe, or Old Stone Age Europe, encompasses the Paleolithic or Old Stone Age in Europe from the arrival of the first archaic humans, about 1.4 million years ago until the beginning of the Mesolithic around 10,000 years ago. This period thus covers over 99% of the total human presence on the European continent. The early arrival and disappearance of Homo erectus and Homo heidelbergensis, the appearance, complete evolution and eventual demise of Homo neanderthalensis and the immigration and successful settlement of Homo sapiens all have taken place during the European Paleolithic.
The Paisley Caves or the Paisley Five Mile Point Caves complex is a system of eight caves in an arid, desolate region of south-central Oregon, United States north of the present-day city of Paisley, Oregon. The caves are located in the Summer Lake basin at 4,520 feet (1,380 m) elevation and face west, carved into a ridge of Miocene and Pliocene era basalts mixed with soft volcanic tuffs and breccias by Pleistocene-era waves from Summer Lake. One of the caves may contain archaeological evidence of the oldest definitively-dated human presence in North America. The site was first studied by Luther Cressman in the 1930s.
The Manis Mastodon site is a 2-acre (1 ha) archaeological site on the Olympic Peninsula near Sequim, Washington, United States, discovered in 1977. During the 1977-78 excavation, the remains of an American mastodon were recovered with a 13,800-year-old projectile point made of the bone from a different mastodon embedded in its rib. The site was placed on the National Register of Historic Places in 1978.
The Anzick site (24PA506), located adjacent to Flathead Creek, a tributary of the Shields River in Wilsall, Park County, Montana, United States, is the only known Clovis burial site in the New World. The term "Clovis" is used by archaeologists to define one of the New World's earliest hunter-gatherer cultures and is named after the site near Clovis, New Mexico, where human artifacts were found associated with the procurement and processing of mammoth and other large and small fauna.
Anzick-1 was a young Paleoindian child whose remains were found in south central Montana, United States, in 1968. He has been dated to 12,990–12,840 years Before Present. The child was found with more than 115 tools made of stone and antlers and dusted with red ocher, suggesting a deliberate burial. Anzick-1 is the only human whose remains are unambiguously associated with the Clovis culture, and is the first ancient Native American genome to be fully sequenced.
El Fin del Mundo is an ancient Pleistocene site near Pitiquito in northwestern Sonora, Mexico. It features Clovis culture period occupation proposed to date to 13,390 calibrated years Before Present, though this is contested.
The peopling of the Americas began when Paleolithic hunter-gatherers (Paleo-Indians) entered North America from the North Asian Mammoth steppe via the Beringia land bridge, which had formed between northeastern Siberia and western Alaska due to the lowering of sea level during the Last Glacial Maximum. These populations expanded south of the Laurentide Ice Sheet and spread rapidly southward, occupying both North and South America, by 12,000 to 14,000 years ago. The earliest populations in the Americas, before roughly 10,000 years ago, are known as Paleo-Indians. Indigenous peoples of the Americas have been linked to Siberian populations by linguistic factors, the distribution of blood types, and in genetic composition as reflected by molecular data, such as DNA.
The coastal migration hypothesis is one of two leading hypotheses about the settlement of the Americas at the time of the Last Glacial Maximum. It proposes one or more migration routes involving watercraft, via the Kurile island chain, along the coast of Beringia and the archipelagos off the Alaskan-British Columbian coast, continuing down the coast to Central and South America. The alternative is the hypothesis solely by interior routes, which assumes migration along an ice-free corridor between the Laurentide and Cordilleran ice sheets during the Last Glacial Maximum.
The Yana Rhinoceros Horn Site is an Upper Palaeolithic archaeological site located near the lower Yana river in northeastern Siberia, Russia, north of the Arctic Circle in the far west of Beringia. It was discovered in 2001, after thawing and erosion exposed animal bones and artifacts. The site features a well-preserved cultural layer due to the cold conditions, and includes hundreds of animal bones and ivory pieces and numerous artifacts, which are indicative of sustained settlement and a relatively high level of technological development. With an estimated age of around 32,000 calibrated years before present, the site provides the earliest archaeological evidence for human settlement in this region, or anywhere north of the Arctic Circle, where people survived extreme conditions and hunted a wide range of fauna before the onset of the Last Glacial Maximum. The Yana site is perhaps the earliest unambiguous evidence of mammoth hunting by humans.