Skip to comments.The First Americans May Have Come By Water
Posted on 12/10/2001 7:30:51 PM PST by blam
The First Americans May Have Come by Water
by E. James Dixon
If the foragers who created Clovis culture walked into North America, they had to pass through the long-described ice-free corridor. But a growing body of evidence indicates that pathway between the great glaciers of the last Ice Age was closed in fact, the way south may have been blocked until centuries after the dawn of Clovis.
If the first Americans could not walk into the New World, how did they get there? Coastal or ocean routes navigated by watercraft are the most likely explanation.
No reliably dated human remains from the Americas are older than about 11,500 radiocarbon years (13,350 calendar years). This, along with other evidence, suggests humans first arrived in the Americas not more than 15,000 years ago (17,950 cal BP), near the end of the last Ice Age, the Late Wisconsin.
The climate was much colder then, and massive glaciers in the east and west formed a huge ice sheet covering most of Canada. The ice blocked access between what is today Alaska and the continental United States. Polar sea ice extended south into the Atlantic, covering Greenland, Iceland, and all but the southernmost areas of Ireland and England.
Because much of the earths water was trapped in glacial ice, sea level was lower. The continental shelves and the floor of the Bering and Chukchi seas were exposed, creating the Bering Land Bridge. The geography of the Ice Age limited possible migration routes into the Americas to the following: the Beringian mid-continental, the Northwest Coastal, the Pacific, and the Atlantic routes.
The Beringian mid-continental route presumes that hunters and gatherers first entered North America from Asia across the Bering Land Bridge. They then moved south into central-western Canada through the hypothetical ice-free corridor. But geologists working in Canada have recently demonstrated that the ice-free corridor did not exist at that time, and that connections between eastern Beringia and areas south of the continental glaciers were not established until about 11,000 years ago (13,020 cal BP).
Supporting this conclusion, paleontologists have found no animal bones dating between about 21,000 to 11,500 years ago in the region formerly believed to have been the ice-free corridor. This evidence demonstrates fairly conclusively that the ice-free corridor did not exist during the last Ice Age. And it precludes a mid-continental route for human entry before about 11,000 years ago.
Deglaciation along the Northwest Coast of North America had begun by about 14,000 years ago (16,800 cal BP) and was sufficiently advanced to enable humans using watercraft to colonize coastal areas by 13,000 years ago (15,350 cal BP). The remains of land and sea mammals, birds, and fish dating to this time have been discovered along the Northwest Coast, demonstrating sufficient resources existed along the coast for people to have survived.
Because earlier geologic interpretations had indicated that the region had been entirely glaciated until about 10,000 years ago (11,350 cal BP), very little archaeological work has been undertaken to explore this region as a possible migration route. So far, no sites have been found that are older than about 10,500 to 10,000 years ago.
Some researchers believe humans may have crossed the vast expanse of the Pacific and colonized South America before anyone reached North America. Support for this theory is based on sites such as Monte Verde in southern Chile and Tiama-Tiama in northern Venezuela, which may be older than the oldest sites in North America. Biological evidence suggests some of the earliest skeletons in South America may share similarities with inhabitants of Polynesia and Australia.
The Atlantic route is championed by archaeologists Dennis Stanford and Bruce Bradley, who have documented a surprising number of technological traits shared between the Clovis complex of North America dating to between 11,500 and 10,900 years ago and the Solutrean tradition of Europe, which ended possibly as late as 16,000 years ago (19,100 cal BP). They hypothesize that Solutrean maritime hunters and fishers may have worked their way along the southern margins of the Atlantic sea ice to the New World during the Late Wisconsin.
The preponderance of linguistic and biological evidence indicates that Native Americans most likely originated somewhere in northeastern Asia. Only the Northwest Coastal and mid-continental routes lead from there to the Americas. Because the mid-continental route was not open until about 11,000 years ago, the most plausible route for the initial colonization of the Americas seems to be along the Northwest Coast.
The colonization of continents is a complex process that spans a long period of time and probably involves many groups of people from different places. Archaeologists must keep their minds open to the many ideas being offered to explain the peopling of the New World.
There are tantalizing biological and technological clues that suggest possible contact, perhaps even colonization, between the Americas and Australia, Polynesia, Europe, and even Africa. The timing and processes of the colonization of the Americas are important because the cultural adaptations of the New Worlds first populations established the foundation for all subsequent cultural development in the Americas and for the rich and diverse cultures that followed.
E. JAMES DIXON is Curator of Archaeology at the Denver Museum of Natural History. His latest book, Bones, Boats & Bison: Archeology and the First Colonization of Western North America, is in publication by University of New Mexico Press.
by Theodore G. Schurr
Recent genetic studies are painting surprising, if tentative, new pictures of the peopling of the Americas complex images with multiple waves of colonists from a number of homelands, the first of them arriving in the New World much earlier than generally believed.
Genes are housed within a cell's nucleus, but mitochondria (bottom left), which carry mitochondrial DNA, are outside the nucleus. The mtDNA is inherited only from the mother (ring on top left).
Molecular genetic research in the past five years suggests the first Americans arrived well before the Clovis culture, the traditional benchmark for human occupation of the New World at about 11,500 radiocarbon years ago (13,350 cal BP). And the data imply that several geographic expansions of ancient peoples contributed to the genetic diversity now seen in aboriginal Siberian and Native American populations.
Several genetic studies have suggested that a single migration from southeastern Siberia and Mongolia populated the New World. However, research by my colleagues and I suggest multiple migrations to the Americas, as well as additional and/or alternative source areas for ancestral Paleoindians, including the lower Amur River between Russia and China.
But whether a single colonizing event or just the first of several population expansions, the initial migration into the New World seems to have occurred at least 20,000 years ago, and perhaps as long ago as 40,000 years. Later, well after the last glacial maximum at about 18,000 years ago, other groups moved into northern North America. These people probably had been inhabiting the Bering land bridge, the then-dry region between Alaska and Siberia that is called Beringia.
Furthermore, while most of the genetic lineages present in modern Native Americans have their antecedents in East Asia and Siberia, recent work has shown that one lineage appears to have its roots in Eurasia, leading to speculation about how it was brought to the Americas.
The two primary genetic systems that have been used in these groundbreaking studies are the mitochondrial DNA (mtDNA), short pieces of genetic material found outside a cells nucleus (where the genetic chromosomes are located), and the Y chromosome, which is present only in males.
These genetic systems have a number of properties that make them invaluable tools for molecular-anthropological studies. First, each is inherited only from one parent: The mtDNA is passed from mother to daughter, and the Y chromosome from father to son. These inheritance patterns mean their analyses are essentially the study of female and male genetic histories within human populations.
Second, these genetic systems generally accumulate mutations in a more or less linear fashion through time, which means permanent and detectable genetic changes occur at a roughly predictable rate. This allows researchers to trace the evolution and divergence of female and male genetic lineages in human groups.
Third, many of the mutations detected in mtDNAs and Y chromosomes correlate with the geographic region in which they first occurred. This makes it possible to reconstruct ancient migration patterns based on the distribution of these mutations, or genetic markers, in different populations.
Finally, these genetic systems are very sensitive to such random processes as genetic drift the changes in gene frequencies that occur in a population over generations. These changes can result from geographic isolation, migration, or population splits, in which some of the people leave to found a new group. Hints of such past events are often recorded in a populations mtDNA and Y chromosome sequences.
The mtDNAs of Native American populations separate primarily into four haplogroups, or lineages, designated A, B, C, and D. Each is defined by a specific set of genetic markers, so their identification is relatively straightforward. Statistical analyses indicate that haplogroups A, C, and D originated about 35,000 to 25,000 years ago in both Siberia and America. By one measure, haplogroup B appeared to be much younger in America (about 15,000 years ago), but other work suggests that it was present in East Asia by at least 30,000 to 24,000 years ago and may have entered the New World during this period. Thus, the molecular data suggest that the four primary haplogroups in Native Americans were brought to the New World before the last glacial maximum.
Most recently, a fifth founding haplogroup, genetically linked to the rare European haplogroup X, has been identified among Native Americans. While present in Native Americans, haplogroup X has not been detected in any East Asian or Siberian population the putative source populations for ancestral Native Americans in whom haplogroups A, C and D commonly occur. It has, however, been observed at low frequencies in a number of European, Middle Eastern, and West Asian groups, suggesting it arose somewhere in this general region.
In addition, haplogroup X is found primarily in North America, whereas the other four haplogroups are found throughout the Americas, albeit at various frequencies. Furthermore, haplogroup X appears to be a relatively ancient arrival, at 30,000 to 15,000 years ago, in the New World.
Collectively, the evidence suggests that haplogroup X originated in a region outside of eastern Siberia and was somehow brought to the Americas, where it became part of the genetic makeup of Paleoindian populations. And it argues against a single migration from southeastern Siberia bearing these mtDNA lineages to the New World; the data suggest instead that the haplogroups present in todays Native Americans arrived with several human migrations that originated in different areas.
The mtDNA data also revealed strong evidence for a post-Ice Age re-expansion of ancient Beringian populations into northern North America. One mutation within haplogroup A (16111T) marks the emergence of these ancestral Beringian populations that gave rise to Native American groups. After the initial occupation of the New World, however, these populations in Beringia became isolated from the Paleoindian groups in the south, perhaps by expanding glaciers. This isolation lasted long enough for the Beringians to diverge genetically, including the appearance of a distinct haplogroup A mutation (16192T).
This genetic marker is found only among the Koryaks, Chukchi, and Eskimos in Siberia and the northwestern tip of North America, and the Na-Dene Indians, including the Navajo in the American Southwest.
Research into both mtDNA and Y chromosome markers is greatly enriching the story of the first Americans. Additional work on these and other genetic systems will likely further refine the story, perhaps revealing new and exciting details about the peopling of the New World.
THEODORE G. SCHURR is at the Department of Genetics at the Southwest Foundation for Biomedical Research in San Antonio, Texas.
by Dennis Stanford and Bruce Bradley
For half a century, archaeologists have assumed that ancestors of the Clovis people long considered the first Americans crossed the Bering Land Bridge from northeast Asia some 12,000 radiocarbon years ago (14,000 calendar years BP), then spread southward across the continent.
Solutrean seafarers may have followed the edge of an icesheet that covered the North Atlantic during the last Ice Age to reach the coast of North America. Years of research in eastern Asia and Alaska have produced little evidence of any historical or technological connection between the Asian Paleolithic (Stone Age) and Clovis peoples. Also, the southeastern United States has produced more Clovis sites than the West, and a few radiocarbon dates suggest some of them may predate those in the western states. If correct, that hardly fits the notion that Clovis technology originated in northeast Asia or Alaska.
Over the years, various scholars have noted similarities between Clovis projectile points and Solutrean points, the product of a Paleolithic culture on the north coast of Spain between 22,000 and 16,500 years ago. Little credence has been given to suggestions of a direct connection between these technologies because of the 4,500-year time gap between the last of Solutrean and the first of Clovis, and because of doubts that people of the Upper Paleolithic could navigate the Atlantic Ocean.
But indirect evidence for Paleolithic ocean travel has been mounting. Although no boats have been found, we now know that by at least 40,000 years ago, watercraft carried a founding population to Australia. By 28,000 years ago, flintknappers were collecting raw materials from islands far off the Japanese coast. And closer to Spain, Paleolithic peoples inhabited some of the Mediterranean islands at least 14,000 years ago.
Solutrean peoples could have used this knowledge of watercraft to travel and exploit marine resources, which would have been especially important during the last glacial maximum, about 18,000 years ago, when most of Europe was covered with ice and competition for diminishing land resources must have been intense. Given these facts, we believe the hypothesis of a western Old World ancestry for Clovis should be reconsidered.
To determine whether the idea was worth additional study, we examined archaeological collections in Spain, France, and Portugal, looking for technological affinities between the European Upper Paleolithic and Clovis. Our cursory examination revealed an amazing correspondence between Solutrean and Clovis; in fact, Solutrean has more in common with Clovis than with Paleolithic technologies that followed it in Europe.
Solutrean and Clovis flintknappers used nearly identical stoneworking technologies. We observed a high degree of correspondence between stone and bone tools, as well as engraved limestone tablets, and caching of extra large bifaces and other tool stock. The Solutrean toolkit is, with a few exceptions, nearly identical to that of Clovis. Although some of the Solutrean concave-base projectile points are heavily thinned, none that we saw exhibited a well-developed Clovis-style flute. Clovis assemblages lack shouldered points and the Solutrean laurel-leaf knife.
A Solutrean origin for the Clovis culture seems a more parsimonious explanation of the evidence than an Asian ancestry. Certainly, if Solutrean industries were found in Siberia, no one would question their historical relationship with Clovis.
The ultimate test of this hypothesis may be found in genetic research on ancient human remains. Michael Brown and colleagues reported in 1998 that mitochrondrial-DNA haplogroup X (a genetic marker of population groups) is found in low frequencies in both European and Native American populations, but not among Asians. This indicated to them that some of the American founders may have come from Europe between 36,000 and 12,000 years ago.
Regardless of whether a Solutrean-Clovis link is eventually proven, exploring this hypothesis should increase our understanding of the development of technological innovations and broaden our knowledge of early peoples of the New World.
DENNIS STANFORD is Chairman of the Anthropology Department at the National Museum of Natural History, Smithsonian Institution.
BRUCE BRADLEY is President of Primitive Tech Enterprises, Inc., in Cortez, Colorado, and Adjunct Professor at Augustana College in Sioux Falls, South Dakota.
by D. Gentry Steele
Early American skulls dont fit neatly into any theoretical box. The skeletal remains of the earliest-known Americans tell a story that is far more complex than previously thought, and it is a story that is still being interpreted.
But statistical analyses of measurements of ancient skulls (10,000 to 9,000 radiocarbon years ago, or 11,350-10,185 calendar years) and more recent Native Americans show that Paleoindians display differences from current American Indians and from modern populations of northeast Asia, the region typically cited as Native Americans ancestral homeland.
Specifically, the early skulls consistently have longer, narrower faces; longer, narrower braincases; a more projecting, mid-facial region; and cheekbones that slope to the rear.
Paleoindian cranio-facial features more closely resemble central and southern Asians, Polynesians, Australians, and some European samples than do most current American Indians. Walter Neves study of South American Paleoindian skulls found similar degrees of distinctiveness from recent populations in North and South America. He notes structural similarities of South American Paleoindians to Australoasian groups.
It should also be noted that American Indian populations across the Americas show at least as much cranio-facial variation as populations of other continents, based on W.W. Howells database of cranial measurements from populations throughout the world. Native Americans are, therefore, not so similar that colonization of the New World must have been a very recent event or have involved a single population.
My colleagues, especially Joseph Powell of the University of New Mexico, and I have been exploring this issue for over a decade. Our results are consistent, but limited by the paucity of very early remains. By 1994, fewer than 25 individuals could be considered at least 8,500 years old (9,509 cal BP), and only four skulls (from two males and two females) were complete enough to permit comparisons of more than one or two traits.
The sample improved recently with two virtually complete male skeletons, both from Nevada Spirit Lake and Wizards Beach and dated to about 9,200 years ago (10,335 cal BP).
To recognize and confirm the distinctiveness of the earliest-known human populations, we have applied an assortment of statistical analyses on various combinations of data from these samples and compared them with modern and prehistoric populations around the world.
The question now becomes this: What caused this distinctive cranio-facial pattern among Paleoindians, and why does it differ from modern Native Americans?
The most common explanation is gene flow: Current Native Americans physically resemble their geographically close northeast Asian neighbors because they are descended from them, while earlier American populations, with other ancestors, were absorbed or displaced. This process could have involved a recent population expanding out of northeast Asia, replacing some existing populations and pushing others into less-productive environments and genetic obscurity.
Another gene-flow model suggests a longer, less-intensive process: The variation in todays Native Americans could result from mixing genes of a founding population with, in local populations, varying amounts of genes from later colonizers.
The original founding population for Paleoindians has been proposed by various researchers, based on physical/genetic characteristics, as early Asian (sometimes referred to as Protoasian or Protomongoloid), southern Asian (similar to the Jomon, an early population of Japan), Australoasian (most notably for South American Paleoindians), and European.
The principal limitation of the gene-flow model is its beguiling simplicity. By relying exclusively on this as the complete explanation of the differences between current Native Americans and the early North American remains, we ignore potentially powerful forces such as genetic drift (the random changes that alter a groups gene frequencies over generations) and natural selection acting on populations as they adapt to local environments. Both processes, after all, have had thousands of years to work on the first Americans. At this stage, none of these three forces gene flow, genetic drift, and natural selection can be ruled out as a cause of the differences between early Paleoindians and later Native Americans.
The weight of the evidence, however, suggests the difference between early American populations and those of more recent times reflects a strong component of gene flow, from either small but rather constant trickles or waves of immigrants, or a short but expansive colonizing event.
Identifying the founding population of Paleoindians is much more difficult because the features that distinguish Paleoindians from more recent Native Americans are shared, at least in part, with a number of populations from the Old World, particularly those of its eastern margins.
Current data are not robust enough to identify precise ancestors of the earliest known colonizers of the New World. But the weight of the cranio-facial evidence clearly indicates we can no longer assume recent Northeast Asians were the first colonizers. I suspect the first colonizers will prove to be populations from southern or central Asia, such as the Jomon of Japan, although the evidence is as equivocal for this as for other views.
More importantly, we must recognize that in the biological world, processes and events are far more complex than our intentionally simplified models. For the peopling of the Americas then, the challenge we face in the future is to develop ways to verify that multiple forces are at work in a population and to tease out the role each plays in the process.
D. GENTRY STEELE is a Professor in the Anthropology Department at Texas A&M University and serves as Faculty Advisor to Texas A&M University Press.
And the folks who settled Jamestown 13 years earlier were...???
The Jamestown settlement in 1607 suffered through some disasters, but it survived as the first permanent colony in North America. It pre-dated the landing at Plymouth by 13 years.
Location: Barstow, California
Calico Early Man Archaeological Site More than 12,000 stone tools dating back perhaps 200,000 years have been located in an excavation begun in 1964 by Dr Louis Leakey. It is one of the oldest sites of prehistoric tools
This paragraph sums up why some American Indian activists would like to suppress such information. If this is true, then the American Indian isn't the "perfect victim"; he's just another conqueror.
Left-wing Indian activists have been working for years to portray the Indian as the perfect victim. They are mythologized as a people living in harmony with each other and with nature; that all was good until the evil White man arrived. In their myth, Paradise is lost in 1492. Stories of "others" get in the way of that tale.
If other populations pre-date the Indian, then what happened to them? If the Indians aren't the perfect beings who fell to the ravenous Whites, then perhaps they simply conquered the others. Many other peoples have done so throughout history.
But that spoils some good PR.
The Activists have a harder time begging political goodies if their clients aren't as angelic as they've been portrayed. Thus to protect the flow of political favor, they seek to suppress information that contradicts the offical mythos. Finds such as Kenniwick Man are to be destroyed and anthropologists who explore the wrong ideas are slandered.
Found: January 1989, at a gravel quarry near Buhl, Idaho
Age: 10,600 years
Discoverers: highway workers
Significance: Having been reburied by Shoshone-Bannock tribes in 1991 before thorough study could occur, Buhl Woman underscores scientists' fears of losing access to ancient Paleoindian skeletons.
Dead before she turned 21, this young woman found a final resting place in a gravel bar beside the Snake River, where windblown sand and silt slowly covered her body. Her right cheek lay atop a pressure-flaked, pointed obsidian tool, perhaps made specially as a grave gift.
In life, Buhl Woman ate abundant bison and elk, as well as salmon heading upriver to spawn. Sloping surfaces and heavily worn enamel on her teeth unusual for someone so young indicate that her diet included frequent doses of sand or grit, as if her meat had been pounded or stoneground into a jerky.
Lines of interrupted growth on her thigh bone tell of stress from illness or malnutrition during childhood, but she grew to a height of 5'2" and otherwise enjoyed good health. What caused her death remains unknown.
(She is/was believed to be related to Kennewick Man).The Americans Indians, as we know them today, were not here prior to 4,000BC (six thousand years ago)
Please immediately post a series of similar articles entitled:
A. First Hawaiians may have come by water;
B. First Britishers may have come by water;
C. First Easter Islanders may have come by water....
You get the picture.
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