Quest for the lost land [Quête de la terre perdue].

Résumé

Until recently, researchers believed our North American roots stretched back only about 11,200 radiocarbon years before present (YBP). These earliest settlers, from a culture now called Clovis, traveled from northeast Asia across the "Beringia landbridge," hunting large mammals with stone tools and colonizing the Americas via an "ice-free corridor" east of the Canadian Rocky Mountains. However, in 1989, archaeologist Tom Dillehay at the University of Kentucky published a two-volume work entitled Monte Verde: A Late Pleistocene Settlement in Chile, which describe a human settlement dated to 12,500 YBP, approximately 1,300 years before Clovis. This site contained non-Clovis stone tools, a child's footprints and a community of dwellings constructed in part from animal skins. Archaeological sites like this and others found south of areas glaciated during the last ice age, and dated to between 12,500 and 11,500 YBP, imply that people had reached the southern tip of South America prior to the recession of the giant ice sheets, leading archaeologists to postulate alternative migration routes. Now geologists are also working on these alternative routes, exploring the region's glacial past to reconstruct a potential path for early peoples along the northwestern coast of North America. Coastal migration In the early 1960s, Calvin Heusser, Alex Kreiger, Kenneth Macgowan and Joseph Hester suggested the possibility of a Pacific coastal migration route for early peoples. In the mid-1970s Knut Fladmark, now at Simon Fraser University in Canada, did extensive analysis of the paleoenvironmental and archaeological data pertaining to a "coastal route," but his work met with little support. However, this all began to change when archaeologist Daryl Fedje from Parks Canada and geologist Heiner Josenhans from the Geological Survey of Canada discovered a forest of standing stumps deep under the marine waters off the Queen Charlotte Islands. Today, the possibility that the Americas' first settlers migrated via a coastal route has become an intriguing and increasingly popular, albeit contentious, theory. As with the ice-free corridor hypothesis, debate continues over whether archaeologists are presumptuous in assuming that the northwest coast of North America could support early migrating humans in their journey southward. Somewhat puzzling, considering the renewed interest in the coastal migration route, is the fact that few sites along the northwest coast of North America are older than 10,000 YBP. In 1997, archaeologist E. James Dixon, now at the University of Colorado at Boulder, and others reported in Geoarchaeology their discovery of a human pelvis and mandible in a cave on Prince of Wales Island, Alaska. The mandible dated to around 9,200 YBP, and a bone tool found in the same cave dated to 10,300 YBP (marine reservoir corrected to circa 9,800 YBP). Although exciting finds, these dates were more than 2,000 years shy of the evidence at Monte Verde. Yet, despite this lack of early archaeological evidence, the coastal migration route is fast becoming the prevailing theory as to how and when the first Americans arrived. Perhaps the coastal migration route is simply riding a wave of popularity, perhaps scientists lack sufficient creative vision of alternative ice-age human lifeways. But as enticing new evidence accumulates, including indications that brown and black bears, caribou and mountain goats survived along North America's northwest coast during and subsequent to the last ice age, the search intensifies to find substantive evidence of the region's ability to support early peoples and artifactual evidence of their presence. The coastal migration route follows continental plate boundaries, most of which are active and subject to major earthquakes. At the edge of the continental plates, the lithosphere is often thin and flexible and thus responds relatively rapidly to changes in eustatic sea level, sedimentation, erosion, glacial and water load