There have been several models of migration to the New World (Human migration into the Americas) proposed by various academic communities. The question of how, when and why humans (Paleo-Indians) first entered the Americas is of intense interest to archaeologists and anthropologists, and has been a subject of heated debate for centuries. Current understanding of human migration into the Americas derives from advances in four integrated disciplines: archeology, physical anthropology, DNA analysis and linguistics.

There is general agreement that America was first settled from Asia by people who migrated across Beringia, the pattern of migration, its timing, and the place of origin in Asia of the peoples that migrated to the Americas remains unclear. In recent years researchers have enroll familiar tools to validate or reject what have become more or less entrenched theories like Clovis first. As new discoveries come to light, past hypotheses are reevaluated and new theories constructed. The archeological evidence suggest that Paleo-Indians first "widespread" habitation of the Americas occurred during the end of the last glacial period, or more specifically what is known as the late glacial maximum, around 16,500 - 13,000 years ago.

Understanding the debate

The chronology of migration models is currently divided into two general approaches. The first is the short chronology theory with the first movement beyond Alaska into the New World occurring no earlier than 15,000 – 17,000 years ago, followed by successive waves of immigrants. The second belief is the long chronology theory, which proposes that the first group of people entered the hemisphere at a much earlier date, possibly 21,000 - 40,000 years ago, with a much later mass secondary wave of immigrants.

One factor fueling the debate is the discontinuity of archaeological evidence between North and South America Paleo-Indian sites. A roughly uniform techno-complex pattern known as Clovis appears in North and Central American sites from at least 13,500 years ago onwards. South American sites of equal antiquity do not share the same consistency and exhibit more diverse cultural patterns. Thus, archaeologists conclude that the "Clovis-first", and Paleo-Indian time frame do not adequately explain complex lithic stage tools appearing in South America. Some theorists seek to develop a colonization model that integrates both North and South American archaeological records.

Mitochondrial DNA studies concluded that the "initial founders" of the Americas emerged from a single-source ancestral population that evolved in isolation, likely in Beringia. The isolation in Beringia might have lasted 5,000 - 15,000 years. Age estimates based on Y-chromosome micro-satellite place diversity of the American Y-chromosome Q-haplo at around 10,000 to 15,000 years ago. These dates are in relative agreement with the age of well-established American archaeological sites showing complete habitation of the continent.

Migrants from northeastern Asia could have walked to Alaska with relative ease when Beringia was above sea level. But traveling south from Alaska to the rest of North America may have posed significant challenges. The two main possible routes proposed south for human migration are: down the Pacific coast or by way of an interior passage along the eastern flank of the Rocky Mountains. When the Laurentide and Cordilleran ice sheets were at their maximum extent, both routes were likely impassable. The Cordilleran sheet reached across to the Pacific shore in the west, and its eastern edge abutted the Laurentide, near the present border between British Columbia and Alberta.Geological evidence suggests the Pacific coastal route was open for overland travel before 23,000 years ago and after 15,000 years ago. During the coldest millennia of the last ice age, roughly 23,000 to 19,000 years ago, lobes of glaciers hundreds of kilometers wide flowed down to the sea. Deep crevasses scarred their surfaces, making travel across them dangerous. Even if people traveled by boat—a claim for which there is currently no direct archaeological evidence as sea level rise has hidden the old coast line — the journey would have been difficult with abundant icebergs in the water. Around 15,000 to 13,000 years ago the coast was presumed ice-free. Additionally, by this time the climate had warmed, and lands were covered in grass and trees. Early Paleo-Indian groups could have readily replenished their food supplies, repaired clothing and tents, and replaced broken or lost tools.

Coastal or watercraft theories have broad implications, one being that Paleo-Indians in North America may not have been purely terrestrial "big-game hunters", but instead were already adapted to maritime or semi-maritime lifestyles. Additionally, it is possible that "Beringian" (western Alaskan) groups migrated into the northern interior only to meet their demise during the last glacial maximum, approximately 20,000 years ago. Thus leavening evidence of occupation in certain areas; however they would not be considered a founding population, unless they had managed to migrate south and populate before the coldest part of the ice-age.

Timeline of archeological, geological and genetic evidence

40,000 B.C. - 25,000 B.C. Paleolithic people move into Beringia across the Bering Land Bridge into western Alaska. Bison (buffalo), mammoths, and mastodons are thought to have migrated from Asia to America about this time. This would imply a land bridge between the continents and would have been a food supply.
30,000 - 20,000 years ago: Mammoth bones, believed to have been chipped by humans, are found at the Yukon's Bluefish Caves and Old Crow Flats sites in the 1970s and 1980s by archeologist Jacques Cinq-Mars and his team. In 2004, Albert Goodyear of the South Carolina Institute of Archaeology and Anthropology announced that radiocarbon dating of a bit of charcoal found in the Topper Site near Allendale County, South Carolina. However, these deposits may have been made by forest fires. (Note: The dates given for the Old Crow and Topper digs have not been completely accepted by the archaeology community.) Geneticists have variously estimated that peoples of Asia and the Americas were part of the same population from 21,000 to 42,000 years ago. Ice-free corridor running north and south through Alberta and the continental glacier called Laurentide ice sheet. Introduced by geologists in the 1950s when stone tools were found in the Grimshaw, Bow River and in Lethbridge Alberta, under glacial sand and gravel are believed to be pre-glacial and therefore may indicate nomadic humans occupied the area. A child's skull found in 1961 near Taber, Alberta is believed to be one of the oldest inhabitants discovered in Alberta. (Note: The conclusions reached in Alberta on dates have not been accepted by the entire archaeology community.) Siberian mammoth hunters believed to have penetrated far into the Arctic where ice-free corridors north during the time are believed found. Theory first introduced by geologist in the late 1970s when core samples indicate ice is no older then 17,000 year old.
23,000 - 16,500 years ago: The Ice Age entombs the northern hemisphere in glaciers, cutting off routes from Siberia to the south. 2002 the presence of the X haplogroup was found in a small percentage of modern indigenous Americans that is known to exist in a few locations in Europe and the Middle East. Subsequent research indicated that the European DNA was not the result of genetic mixing after Columbus. However the time estimates on haplogroup X entering Americas is around 15,000 to 20,000 years ago. Genetic evidence (2007-2009) suggests the Beringia population first genetic diversification from Asian populations occurred. An article in the American Journal of Human Genetics states "Here we show, by using 86 complete mitochondrial genomes, that all Native American haplogroups, including haplogroup X, were part of a single founding population, thereby refuting multiple-migration models.
16,500 - 13,000 years ago: Geologists report this is when receding glaciers reopened an ice-free corridor through Canada between Alaska and the rest of the Americas. Massive flooding would have created large lakes covering vast areas of north America with glacial waters. Age estimates based on Y-chromosome micro-satellite place diversity of the American Q-Haplo at around 10,000 to 15,000 years ago. Mass extinction of large fauna begins due to climate change and perhaps hunting. The Dire Wolf, Smilodon, Cave Lion, Giant beaver, Ground sloth, Mammoth, American Mastodon, American Camel, American Equine, and American lion all become extinct by 11,000 years ago. Pre-Clovis sites uncovered from 1973-1978 Meadowcroft Rockshelter in Pennsylvania site indicated occupancy as early as 16,000 years ago and possibly as long as 19,000 years ago. Dates in excess of 19,000 years have been claimed for the deepest occupation layer uncovered. pre-Clovis sites found in Monte Verde, located along Chinchihuapi Creek, in Chile. A crew of eighty people, led by Tom Dillehay of the University of Kentucky, excavated the site from 1977-1985. A coastal migration could explain how people arrived in Monte Verde. 2000, archaeologists say people were living at Cactus Hill, Virginia where stone tools and charcoal from a fire pit are found.
15,000 - 13,000 years ago: The Taima Taima mastodon kill/butchering site in Falcon, Venezuela was first excavated by J.M. Cruxent in the 1960s and 1970s. It is one of the earliest archaeological sites that is pre-Clovis. In l976 a broken El Jobo point (red arrow) was found inside the pubic cavity of a partially disarticulated and butchered young mastodon whose bones had been cut, with a jasper flake found near the left ulna of the animal. Peñon women found by an ancient lake bed near Mexico City in 1959. Mention is made of the possibility of Solutrean peoples migrating to the area 15,000 to 20,000 years ago.. El Abra sites located in the valley east of the city of Zipaquirá, Colombia. First excavated by Gonzalo Correal and associates in the late 1970s and early 1980s. 3,072 pieces found indicate it was inhabited continuously for over 7,000 years. At Paisley Caves in the Cascade Range of Oregon, archaeologists find a scattering of human coprolites, or fossil feces in 2003. The mitochondrial DNA extracted from coprolites linked the cave dwellers to two genetic groups of early Americans that arose 14,000 to 18,000 years ago.
13,500 – 12,000 years ago: The Ice Age is ending, melting glaciers have raised sea levels 120 meters and submerged the land bridge between Alaska and Siberia. Geologic evidence indicates that by 11,500 years ago, the Cordilleran and Laurentide ice sheets had retreated far enough to open a habitable ice-free corridor between them. The exposed land was dry and probably restored enough to support plants and animals, which the migrating hunter-gatherer followed. Clovis theory - People were living near Clovis, New Mexico where tools from this era were found in the 1930s. This find gave rise to the widely held "Clovis First" theory that people spread through the Americas only after the Ice Age. The Clovis culture was believed replaced by several more localized regional cultures, such as the Folsom tradition, from the time of the Younger Dryas cold climate period.. Peru coastal region inhabitants fished with nets and bone hooks, collecting seafood such as crabs and sea urchins.
12,000 - 10,000 years ago: Ice age over, climate similar to present temperatures. Old migration theories believe first widespread migration in South America and subsequently a dramatic rise in population all over the Americas, introduced in the 1930s. The Maritimes of Canada are settled by Paleo-Indians. Sites in and around Belmont, Nova Scotia have evidence indicating small seasonal hunting camps, perhaps re-visited over many generations. Luzia Woman's skull and other bones excavated in the Lagoa Santa, Brazil area by French archaeologist Annette Laming-Emperaire in the 1970s. By 2006, Lagoa Santa sites had produced no fewer than 75 well-preserved ancient skulls. 1994, University of California, Riverside anthropologist R. Erv Taylor examined seventeen of the Spirit Cave artifacts near Fallon, Nevada from the 1940s using mass spectrometry. The results indicated that a mummy was approximately 9,400 - 10,200 years old — older than any previously known North American mummy. Unique markers found in DNA recovered from an Alaskan tooth were found in specific coastal tribes, and were rare in any of the other indigenous peoples in the Americas. This finding lends substantial credence to a migration theory that at least one set of early peoples moved south along the west coast of the Americas in boats.
9,000 - 8,000 years ago: Remains, known as Kennewick Man, are found in 1996 on the Columbia River near Kennewick, Washington. A skull and more than 300 bones and bone fragments were found at the site, making up among the oldest, best preserved, and most complete human remains ever found in North America. Initial radiocarbon dating indicated the remains were between 7,000 and 9,500 years old. A leaf-shaped projectile found on the body was long, broad and had serrated edges, all fitting the definition of a Cascade point. This type of point is a feature of the Cascade phase, occurring in the archaeological record from roughly 6000 to over 8500 years ago. 1930s-1990s no major Central American archaeological sites that go back more than 9,000 years have been found. Isolated finds of stone tools in Belize, Nicaragua and Costa Rica indicates that such sites almost certainly exist. Lack of funding for exploration in the areas has postponed likely finds. Tehuacan Valley of Mexico - people are living in rock shelters and using stone cooking pots, which were left in the center of the hearth. Maize was to be used in the same valley between 7,000 - 6,000 years ago.

Genetics

Molecular genetics study suggests that Amerindian populations derived from a theoretical single founding population, possibly from only 50 to 70 genetic contributors. Preliminary research, restricted to only 9 genomic regions (or loci) have shown a genetic link between original Americas and Asia populations. The study does not address the question of separate migrations for these groups, and excludes other DNA data-sets.

The American Journal of Human Genetics released an article in 2007 stating "Here we show, by using 86 complete mitochondrial genomes, that all Indigenous Americans haplogroups, including Haplogroup X , were part of a single founding population." Amerindian groups in the Bering Strait region exhibit perhaps the strongest Haplogroup Q1a3a to Siberian peoples. The genetic diversity of Amerindian indigenous groups increase with distance from the assumed entry point into the Americas. Certain genetic diversity patterns from West to East suggest at least some coastal migration events. Geneticists have variously estimated that peoples of Asia and the Americas were part of the same population from 42,000 to 21,000 years ago. To be sure, Amerindian groups in the Bering Strait region exhibit perhaps the strongest DNA or mitochondrial DNA relations to Siberian peoples. The genetic diversity of Amerindian groups seems to increase with distance from the assumed entry point into the Americas. Certain genetic diversity patterns from West to East may suggest at least some coastal migration events.

The American Journal of Physical Anthropolog links the DNA retrieved from a 10,000-year-old fossilized tooth from an Alaskan island, with specific coastal tribes in Tierra del Fuego, Ecuador, Mexico and California. Unique markers found in DNA recovered from the Alaskan tooth were found in these specific coastal tribes, and were rare in any of the other indigenous peoples in the Americas. This finding lends substantial credence to a migration theory that at least one set of early peoples moved south along the west coast of the Americas in boats. A previous study (Eshleman et al. 2004) showed that mtDNA (human mitochondrial DNA) from indigenous populations in coastal British Columbia showed similarities to coastal populations in Southern California, while inland populations in both localities differed markedly.

Land bridge theory

Also known as the Bering Strait Theory or Beringia theory, the Land Bridge theory has been widely accepted since the 1930s. This model of migration into the New World proposes that people migrated from Siberia into Alaska, tracking big game animal herds. They were able to cross between the two continents by a land bridge called the Bering Land Bridge, which spanned what is now the Bering Strait, during the Wisconsin glaciation, the last major stage of the Pleistocene beginning 50,000 years ago and ending some 10,000 years ago, when ocean levels were lower than today. This information is gathered using oxygen isotope records from deep-sea cores. An exposed land bridge that was at least 1,000 miles wide existed between Siberia and the western coast of Alaska. In the "short chronology" version, from the archaeological evidence gathered, it was concluded that this culture of big game hunters crossed the Bering Strait at least 12,000 years ago and could have eventually reached the southern tip of South America by 11,000 years ago.

Synopsis

At some point during the last Ice Age, about 17,000 years ago, as the ice sheets advanced and sea levels fell, people first migrated from the Eurasian landmass to the Americas. These nomadic hunters were following game herds from Siberia across what is today the Bering Strait into Alaska, and then gradually spread southward. Based upon the distribution of Amerind languages and language families, a movement of tribes along the Rocky Mountain foothills and eastward across the Great Plains to the Atlantic seaboard is assumed to have occurred at least some 13,000 to 10,000 years ago.

Clovis culture

This big game-hunting culture has been labeled the Clovis culture, and is primarily identified with fluted projectile points. The culture received its name from artifacts found near Clovis, New Mexico, the first evidence of this tool complex, excavated in 1932. The Clovis culture ranged over much of North America and appeared in South America. The culture is identified by distinctive "Clovis point", a flaked flint spear-point with a notched flute by which it was inserted into a shaft; it could then be removed from the shaft for traveling. This flute is one characteristic that defines the Clovis point complex.

Dating of Clovis materials has been by association with animal bones and by the use of carbon dating methods. Recent reexaminations of Clovis materials using improved carbon-dating methods produced results of 11,050 and 10,800 radiocarbon years B.P. (before present). This evidence suggests that the culture flowered somewhat later and for a shorter period of time than previously believed. Michael R. Waters of Texas A&M University in College Station and Thomas W. Stafford Jr., proprietor of a private-sector laboratory in Lafayette, Colorado and an expert in radiocarbon dating attempted to determine the dates of the Clovis period. The heyday of Clovis technology has typically been set between 11,500 and 10,900 radiocarbon years B.P. (The radiocarbon calibration is disputed for this period, but the widely used IntCal04 calibration puts the dates at 13,300 to 12,800 calendar years B.P.). In a controversial move, Waters and Stafford conclude that no fewer than 11 of the 22 Clovis sites with radiocarbon dates are "problematic" and should be disregarded—including the type site in Clovis, New Mexico. They argue that the datable samples could have been contaminated by earlier material. This contention was received as highly controversial by many in the archaeological community.

Clovis-type artifacts seem to disappear from the archaeological record after the hypothesized Younger Dryas impact event roughly 12,900 years before the present. The effects of the event possibly caused a decline in post-Clovis human populations and shifts in culture and behavior patterns.

Problems with Clovis migration models

Significant problems arise with the Clovis migration model. If Clovis people radiated south after entering the New World and eventually reached the southern tip of South America by 11,000 years ago, this leaves only a short time span to populate the entire hemisphere. Another complication for the Clovis-only theory arose in 1997, when a panel of authorities inspected the Monte Verde site in Chile, concluding that the radiocarbon evidence predates Clovis sites in the North American Midwest by at least 1,000 years. This supports the theory of a primary coastal migration route that moved South along the coastline faster than those that migrated inland into the central areas of the Americas. Many excavations have uncovered evidence that subsistence patterns of early Americans included foods such as turtles, shellfish, and tubers. This is quite a change of diet from the big game mammoths, long-horn bison, horse, and camels that early Clovis hunters apparently followed east into the New World.

At the Topper archaeological site (located along the banks of the Savannah River near Allendale, South Carolina) investigated by University of South Carolina archaeologist Dr. Albert Goodyear, charcoal material recovered in association with purported human artifacts returned radiocarbon dates of up to 50,000 years BP. This would indicate the presence of humans well before the last glacial period, nevertheless considerable doubt over the validity of these findings has been raised by many other researchers, and the pre-Clovis Topper dates remain controversial.

Pre-Clovis dates have been claimed for several sites in South America, but these early dates have yet to be verified unequivocally.

Recent discoveries of human coprolites (desiccated feces) found deeply buried in an Oregon Cave, indicates the presence of humans in North America as much as 1,200 years prior to the Clovis culture.

Watercraft migration theories

Earlier finds have led to a pre-Clovis culture theory encompassing different migration models with an expanded chronology to supersede the "Clovis-first" theory.

Pacific coastal models

Pacific models propose that people reached the Americas via water travel, following coastlines from northeast Asia into the Americas. Coastlines are unusually productive environments because they provide humans with access to a diverse array of plants and animals from both terrestrial and marine ecosystems. While not exclusive of land-based migrations, the Pacific 'coastal migration theory' helps explain how early colonists reached areas extremely distant from the Bering Strait region, including sites such as Monte Verde in southern Chile and Taima-Taima in western Venezuela. Two cultural components were discovered at Monte Verde near the Pacific Coast of Chile. The youngest layer is radiocarbon dated at 12,500 radiocarbon years (~14,000 cal BP) and has produced the remains of several types of seaweeds collected from coastal habitats. The older and more controversial component may date back as far as 33,000 years, but few scholars currently accept this very early component.

Other coastal models, dealing specifically with the peopling of the Pacific Northwest and California coasts, have been advocated by archaeologists Knut Fladmark, Roy Carlson, James Dixon, Jon Erlandson, Ruth Gruhn, and Daryl Fedje. In a 2007 article in the Journal of Island and Coastal Archaeology, Erlandson and his colleagues proposed a corollary to the coastal migration theory—the kelp highway hypothesis—arguing that productive kelp forests supporting similar suites of plants and animals would have existed near the end of the Pleistocene around much of the Pacific Rim from Japan to Beringia, the Pacific Northwest, and California, as well as the Andean Coast of South America. Once the coastlines of Alaska and British Columbia had deglaciated about 16,000 years ago, these kelp forest (along with estuarine, mangrove, and coral reef) habitats would have provided an ecologically similar migration corridor, entirely at sea level, and essentially unobstructed.

Australia/Oceania model

As early as 1787 Chilean naturalist Juan Ignacio Molina mentioned the possibility of South America being populated from south Asia through the "infinite island chains" of the Pacific while north America could have been populated from Siberia. Some anthropologists such as Paul Rivet have proposed that peoples of Oceania or southeast Asia crossed the Pacific Ocean and arrived in South America long before the Siberian hunter-gatherers. These hypothetical Pre-Siberian American Aborigines populated much of South America before being nearly exterminated and/or absorbed by the Siberian migrants coming from the north. Some of the theories involve a southward migration from or through Australia and Tasmania, hopping Subantarctic islands and then proceeding along the coast of Antarctica and/or southern ice sheets to the tip of South America sometime during the last glacial maximum.

There have been well-dated stratigraphic studies that point to people entering Australia some 40,000 years ago. At this period Australia was not connected to another continent, which leads to the assumption that it was reached by watercraft. If Australia was reached in this fashion, some reason that the New World could have been reached in the same way. Proponents of this model have pointed to cultural and phenotypical similarities between the Aboriginal of Australia and the Selknam and Yaghan tribes of southern Patagonia. The theory of Australoid migration to the Americas has earned little scientific support as there is no genetic evidence matching indigenous Australians with South American populations. This model is taught in Chilean schools together with the land bridge model .

A recent study claimed that the Mapuche pre-Columbian Araucana chicken came from Polynesia by analysing their DNA; [43136] [43137] [43138] [43139] this suggests a more recent contact between the Mapuche and Polynesia. Another recent study has contradicted this claim stating that the DNA found in the chicken bone was closer to post colonial European chickens. [43140][43141]

One of the earliest known sites of human occupation in the Americas, Monte Verde, lies within what was later to become Huilliche territory, although there is currently no demonstrated link between the Monte Verde people and the Mapuche.

Southeast Asians: Paleoindians of the Coast

The boat-builders from Southeast Asia may have been one of the earliest groups to reach the shores of North America. One theory suggests people in boats followed the coastline from the Kurile Islands to Alaska down the coasts of North and South America as far as Chile [2 62; 7 54, 57]. The Haida nation on the Queen Charlotte Islands off the coast of British Columbia may have originated from these early Asian mariners between 25,000 and 12,000. Early watercraft migration would also explain the habitation of coastal sites in South America such as Pikimachay Cave in Peru by 20,000 years ago and Monte Verde in Chile by 13,000 years ago [6 30; 8 383].

"'There was boat use in Japan 20,000 years ago,' says Jon Erlandson, a University of Oregon anthropologist. 'The Kurile Islands (north of Japan) are like stepping stones to Beringia,' the then continuous land bridging the Bering Strait. Migrants, he said, could have then skirted the tidewater glaciers in Canada right on down the coast." [7 64]'

Atlantic coastal model

Archaeologists Dennis Stanford and Bruce Bradley champion the coastal Atlantic route. Their Solutrean Hypothesis is also based on evidence from the Clovis complex, but instead traces the origins of the Clovis toolmaking style to the Solutrean culture of Ice Age Western Europe. They have hypothesized that Solutrean hunters and fishers may have worked their way along the southern margins of the Atlantic sea ice to North America. Their argument is based on technological analysis of the similarities between Solutrean and Clovis flint-knapping techniques. Their book on the Solutrean Hypothesis is scheduled for publishing in 2009.

Other Atlantic migration proponents include the French archaeologist Remy Cottevieille-Giraudet, who in the 1930s suggested a European Cro-Magnon origin of the Algonquian peoples. In 1963, Emerson Greenman proposed a hypothetical Atlantic migration during the Upper Paleolithic, also citing New World similarities with Solutrean tools as well as art. He suggested that the Beothuk people of Newfoundland, among others, may have been at least partial descendants of that migration. According to a research report on Beothuk DNA published in 2007, " the data do not lend credence to the proposed idea that the Beothuk (specifically, Nonosabasut) were of admixed (European-Native American) descent."

Problems with evaluating coastal migration models

The coastal migration models provide a different perspective on migration to the New World, but they are not without their own problems. One of the biggest problems is that global sea levels have risen over 100 metres since the end of the last glacial period, and this has submerged the ancient coastlines which maritime people would have followed into the Americas. Finding sites associated with early coastal migrations is extremely difficult—and systematic excavation of any sites found in deeper waters is challenging and expensive. If there was an early pre-Clovis coastal migration, there is always the possibility of a “failed colonization.” Another problem that arises is the lack of hard evidence found for a “long chronology” theory. No sites have yet produced a consistent chronology older than about 12,500 radiocarbon years (~14,500 calendar years) , but South America has still seen only limited research on the possibility of early coastal migrations.

The Dyukhtai of Northeast Asia

Archaeological sites found in Dyukhtai Cave and other sites in the Aldan River valley have yielded remains of a culture that may be a potential Paleoindian ancestor. This culture occupied the region from 35,000-12,000 years ago. The Dyukhtai or similar Northeast Asian cultures may have entered the New World through Beringia and spread into British Columbia [1 140]. It is thought that they pursued Pleistocene mammals such as the giant beaver, goats, elk, ancient reindeer (early caribou), horses, Yukon camels, steppe bison, musk ox, mastodons, and woolly mammoths.

The chief characteristic of the Dyukhtai was their manufacture of microliths or microblades. Microblades are small flakes less than 1 1/4 inches long, with a sharp edge and a "backed" or blunted edge that could be guided with the index finger to sever meat from a carcass. Microblades could also be incorporated into composite tools such as an arrow or sickle. Thousands of microblades have been found at upper Paleolithic Stone Age sites. They have been found north of Mongolia together with projectile points and hand-carved ivory statuettes. The earliest of several sites there has been dated at 45,000 years ago. Microblades appeared in Japan by 20,000 during the LGM when the island was still a peninsula and reachable by land [1 144, 202; 3 189-191].

Microblade manufacture was an important event in human history and its appearance corresponds roughly to the end of the Middle Paleolithic 60,000 years ago. Over 98% of all human history is encompassed by the period of time that began with the appearance of Australopithecus afarensis [e.g. "Lucy"]--a maker and user of Oldowan chopper tools—and ended with the manufacture of microblades by lower-upper Stone Age cultures such as the "Dyukhtai".

See also

Further reading

1. Jody Hey, " On the Number of New World Founders: A Population Genetic Portrait of the Peopling of the Americas", Public Library of Science Biology, 3(6):e193 (2005)
2. Dyke, A.S., A. Moore, and L. Robertson, 2003, Deglaciation of North America. Geological Survey of Canada Open File, 1574. (Thirty-two digital maps at 1:7 000 000 scale with accompanying digital chronological database and one poster (two sheets) with full map series.)
3. Dickason, Olive. Canada's First Nations: A History of the Founding Peoples from the Earliest Times. 2nd edition. Toronto: Oxford University Press, 1997.
4. Richmond, G.M. and D.S. Fullerton, 1986, "Summation of Quaternary glaciations in the United States of America", in Quaternary Science Reviews, vol. 5, pp. 183-196.
5. # Martin, Paul S. (2005): Twilight of the mammoths: Ice Age extinctions and the rewilding of America. University of California Press, Berkeley. ISBN 0-520-23141-4
6. PLoS Genet 3(11): e185. doi:10.1371/journal.pgen.0030185
7. "DNA Ties Together Scattered Peoples," Los Angeles Times (accessed September 11, 2006)
8. Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling - Firestone et al. 104 (41): 16016 - Proceedings of the National Academy of Sciences
9. Fossilized human feces rewrite ancient history
10. The Geographical, Natural and Civil History of Chili, Volume II
11. Melanie Kuch, Darren R. Gröcke, Martin C. Knyf, M. Thomas P. Gilbert, Ban Younghusband, Terry Young, Ingeborg Marshall, Eske Willerslev , Mark Stoneking , Hendrik Poinar, "A preliminary analysis of the DNA and diet of the extinct Beothuk: A systematic approach to ancient human DNA" American Journal of Physical Anthropology Volume 132 Issue 4, Pages 594 - 604 [1]

References

• Dixon, E. James. Quest for the Origins of the First Americans. University of New Mexico Press. 1993.
• Dixon, E. James. Bones, Boats, and Bison: the Early Archeology of Western North America. University of New Mexico Press. 1993.
• Erlandson, Jon M. Early Hunter-Gatherers of the California Coast. Plenum Press. 1994.
• Erlandson, Jon M. The Archaeology of Aquatic Adaptations: Paradigms for a New Millennium. Journal of Archaeological Research, Vo. 9, 2001. Pp. 287-350.
• Erlandson, Jon M. Anatomically Modern Humans, Maritime Migrations, and the Peopling of the New World. In The First Americans: The Pleistocene Colonization of the New World, edited by N. Jablonski, 2002. Pp. 59-92. Memoirs of the California Academy of Sciences. San Francisco.
• Erlandson, Jon. M., M. H. Graham, Bruce J. Bourque, Debra Corbett, James A. Estes, & R. S. Steneck. The Kelp Highway Hypothesis: Marine Ecology, The Coastal Migration Theory, and the Peopling of the Americas. Journal of Island and Coastal Archaeology, Vo. 2, 2007. Pp. 161-174.
• Jason A. Eshleman, Ripan S. Malhi, and David Glenn Smith, "Mitochondrial DNA Studies of Native Americans: Conceptions and Misconceptions of the Population Prehistory of the Americas", Evolutionary Anthropology, 12:7–18 (2003)
• Fedje, & Christensen. Modeling Paleoshorelines and Locating Early Holocene Coastal Sites in Haida Gwaii. American Antiquity, Vol. 64, #4, 1999. Pp. 635-652.
• E. F. Greenman, "The Upper Palaeolithic and the New World", Current Anthropology, 4: 41–66 (1963)
• Jody Hey, " On the Number of New World Founders: A Population Genetic Portrait of the Peopling of the Americas", Public Library of Science Biology, 3(6):e193 (2005).
• Jones, Peter N. Respect for the Ancestors: American Indian Cultural Affiliation in the American West. Bauu Institute Press. 2005.
• Matson and Coupland. The Prehistory of the Northwest Coast. Academic Press. New York. 1995.
• Bradley, Michael, "The Black Discovery Of America: Amazing evidence of daring voyages by ancient West African mariners" Toronto, Canada: Personal Library Publishers, 1981 ISBN 0-920510-36-1.
• Adovasio, J. M., with Jake Page. The First Americans: In Pursuit of Archaeology’s Greatest Mystery. New York: Random House, 2002.
• Bradley, B. and Stanford, D. "The North Atlantic ice-edge corridor: a possible Palaeolithic route to the New World." World Archaeology 34, 2004.
• Bradley, B. and Stanford, D. "The Solutrean-Clovis connection: reply to Straus, Meltzer and Goebel." World Archaeology 38, 2006.
• Lauber, Patricia. Who Came First? New Clues to Prehistoric Americans. Washington, D.C.: National Geographic Society, 2003.
• Snow, Dean R. “The First Americans and the Differentiation of Hunter-Gatherer Cultures.” In Bruce G. Trigger and Wilcomb *E. Washburn, eds., The Cambridge History of the Native Peoples of the Americas, Volume I: North America (Cambridge: Cambridge University Press, 1996), 125-199.
• Jones, Peter N. "Respect for the Ancestors: American Indian Cultural Affiliation in the American West." Boulder, CO: Bauu Press. 2004
• Dixon, E. James. Bones, Boats and Bison: the Early Archeology of Western North America. University of New Mexico Press. 1999.
• Evidence Supports Earlier Date for People in North America, April 4, 2008

Bibliography

1. Gowlett, John. Ascent To Civilization. New York: Alfred A. Knopf, 1984.
2. Petit, Charles W. "Rediscovering America." U. S. News & World Report, October 12, 1998.
3. Fagan, Brian M. The Journey from Eden. London: Thames and Hudson, 1990.
4. Gilsen, Leland. "Pleistocene Adaptations." May 29, 1999. Oregon Archaeology: Prehistory. June 2, 2000 [1].
5. Beringia Research. Yukon Beringia Interpretative Centre. Dec. 7, 2000 [2].
6. Coe, Michael, Dean Snow, and Elizabeth Benson. Atlas of Ancient America. New York: Facts On File Publications, 1986.
7. Begley. Sharon and Andrew Murr. "The First Americans." Newsweek, April 26, 1999.
8. Roosevelt, A. C. et al. "Paleoindian Cave Dwellers in the Amazon: The Peopling of the Americas." Science, April 19, 1996.
9. Price, Douglas and Gary Feinmen, editors. "Monte Verde Early Hunter-Gatherers in South America." Images of the Past. 1997.
10. Surovell, Todd A. "Early Paleoindian Women, Children, Mobility, and Fertility." American Antiquity, 65 (3), 2000