Only a couple of years ago, archaeologists knew, or thought they knew, when and how human beings ended up in the American continent. The story went like this. About 15,000 years ago, the Wisconsinan glacier was at its maximum, effectively blocking all entrance to the continents south of the Bering Strait. Somewhere between 13,000 and 12,000 years ago, an "ice free corridor" opened up in what is now interior Canada between the two main ice sheets. That part remains undisputed. Along the ice free corridor, or so we thought, people from Northeast Asia began to enter the North American continent, following megafauna such as woolly mammoth and mastodon. We called those people Clovis, after the discovery of one of their camps near Clovis, New Mexico. Archaeologists have found their distinctive artifacts all over North America. Eventually, according to the theory, Clovis descendants pushed southward, populating the southern 1/3 of North America and all of South America, but in the meantime adapting their hunting lifeways for a more generalized hunting-and-collecting strategy. The southerners are known generally as Amerinds. Around 10,500 years BP, a second big migration came across from Asia, and became the Na-Dene peoples settling the central portion of the North American continent. Finally, around 10,000 years ago, a third migration came across and settled in the northern reaches of the North American continent and Greenland and were the Eskimo and Aleut peoples.
Evidence supporting this scenario included the fact that none of the archaeological sites in the North American continent predated 11,200 BP. Well, some of them actually did, like Meadowcroft Rockshelter in Pennsylvania, but there was always something wrong with the dates from these sites, either context or contamination was suggested. Linguistic data was called upon and three broad categories of language were identified, roughly paralleling the Amerind/Na-Dene/Eskimo-Aleut tri-part division. Archaeological sites were identified in the "ice free corridor." Most of the early sites were clearly Clovis or at least megafauna-adapted lifestyles.
Monte Verde and the First American ColonizationAnd then, in early 1997, one of the occupation levels at Monte Verde, Chile--far southern Chile--was unequivocally dated 12,500 years BP. More than a thousand years older than Clovis; 10,000 miles south of the Bering Strait. The site contained evidence of a broad-based subsistence, including mastodon, but also extinct llama, shellfish, and a variety of vegetables and nuts. Huts arranged in a group provided shelter for 20-30 people. In short, these "preClovis" people were living a lifestyle far different than Clovis, a lifestyle closer to what we would consider Late Paleo-Indian or Archaic patterns.
Recent archaeological evidence at Charlie Lake Cave and other sites in the so-called "Ice Free Corridor" in British Columbia indicates that, contrary to our earlier assumptions, peopling of the interior of Canada did not take place until after the Clovis occupations. No dated megafauna fossils are known in the Canadian interior from about 20,000 BP until about 11,500 BP in southern Alberta and 10,500 BP in northern Alberta and northeastern British Columbia. In other words, settlement of the Ice Free Corridor occurred from the south, not the north.
Migration When and From Where?The resulting theory begins to look like this: Migration into the Americas had to have taken place either during the glacial maximum--or what is more likely, before. That means at least 15,000 years BP, and likely around 20,000 years ago or more. One strong candidate for primary route of entrance is by boat or on foot along the Pacific coast; boats of one sort or another have been in use at least 30,000 years. Evidence for the coastal route is slim at present, but the coast as the new Americans would have seen it is now covered by water and the sites may be difficult to find. The people who traveled into the continents were not primarily dependent on megafauna, as Clovis peoples were, but rather generalized hunter-gatherers, with a broad base of subsistence.
Most astonishingly, the human skeletal remains recovered dating to these times, such as the Kennewick Man, are providing genetic and morphological proof that the earliest peoples on the continent were not typically Asian, as was expected. I'll address that in Part V: So who was "pre-Clovis"?
Kennewick Man Table of Contents | Part 3: But is the Kennewick Man Caucasoid? | Part 4: How Were the Americas Populated? | Part 5: What does "PreClovis" Mean?