Coastal Migration - Coastal Migration Hypothesis in The New World

Coastal Migration Hypothesis in The New World

Further information: Settlement of the Americas

Sometimes, the theory is extended to cover onwards migration, via the Bering Strait (which was a land bridge during the last ice age), into North America, and then onwards to Central and South America along the western coast. Findings such as the report that the sediments in the Port Eliza caves on Vancouver Island, which indicated the possibility of survivable climate until 16 kybp in the area, have helped bolster the hypothesis recently. However, despite such research, the postulate is still subject to considerable debate. For the Pacific Northwest, Carlson, and others have argued for a coastal migration from Alaska pre-10,000 B.P. that predates the migration of Clovis people moving south through an ice-free corridor located near the continental divide. These people were followed by the Clovis culture, which some archaeologists believe moved south from Alaska through an ice-free corridor located between modern British Columbia and Alberta. Recent dating of Clovis and similar paleoindian sites in Alaska suggest that Clovis technology actually moved from the south into Alaska following the melting of the continental glaciers about 10,500 years ago.

As the ice sheets began to melt, it became possible for riverine-adapted people who made and used microblade technology to move west to the Northwest coast. A second migration of the Denali culture at around 10,700 b.p. brought peoples down the coast from Alaska. Carlson hypothesizes that a population with a maritime adaptation could have travelled south from Alaska down the coastal islands by watercraft, settling as the ice receded, then moving up rivers to the interior. This would account for early finds at Ground Hog Bay in SE Alaska and Namu, about 800 km south of Ground Hog Bay near modern Bella Coola dating to 10,180 +/− 800 b.p. and 9700 b.p., respectively. According to the Matson and Coupland dual migration hypothesis, Namu and Ground Hog Bay represent a second migration while the initial migration route south was through the ice free corridor. Part of the difficulty is the lack of site data prior to 10,000 b.p. as well as the limited number of archaeological investigations into the coastal migration model. Other factors affecting migration models are sea level changes and the question of available land mass to support migrating groups of people.

Evidence from Southeast Alaska and Haida Gwaii (Queen Charlotte Islands) in British Columbia, provides some data about food and land resources during the last glacial maximum. Fedje and Christensen (1999) have identified several sites on Haida Gwaii that date to post 9000 b.p. (642). The oldest human remains known from Alaska or Canada are from On Your Knees Cave, which is on Prince of Wales Island in Southeast Alaska. The individual, a young man in his early twenties when he died, has been dated to 10,300 years ago and isotopic analyses indicate the individual was raised on a diet primarily of marine foods. These data suggest that there are a number of submerged sites just beyond the shorelines of Haida Gwaii (Fedje & Christensen, 1999) and along the coast of Southeast Alaska. Paleoecological evidence suggests that travel along the coast would have been possible between 13,000 and 11,000 b.p. as the ice sheets began retreating. Between 13,000 and 10,500 b.p. Haida Gwaii had more than double its current land area (Fedje & Christensen, 1999:638). This area was flooded as the ice sheets began to melt between 11,000 and 9,000 b.p. (Ibid). Therefore any evidence of human occupation would now be below sea level. Conversely, older sites that are located near modern shorelines would have been approximately 15 miles from the coast (Ibid). The antiquity of the lithic scatters that Fedje and Christensen (1999) have found in intertidal zones along the Haida Gwaii coast suggests an early human occupation of the area.

Fedje and Christensen (1999) support Carlson (1990), and Fladmark's (1975, 1979 & 1989) initial coastal migration model rather than the ice free corridor model proposed by Matson and Coupland (1995) through their investigations of intertidal zones on Haida Gwaii. The coastal region was quite hospitable by 13,000 b.p. to peoples with watercraft and a maritime adaptation. Furthermore, Fedje and Christensen (1999) argue that the coast was likely colonized before 13,000 b.p. (648). This assertion is based largely on watercraft evidence from Japan and Australia before 13000 b.p. If maritime peoples colonized Island Southeast Asia, Australia, western Melanesia, the Ryukyu Islands, and Japan between 50,000 and 35,000 years ago, they may well have been capable of migrating from Northeast Asia into the Americas as the North Pacific Coast warmed and deglaciated after about 16,000 years ago. Although no boats have been recovered from early Northwest Coast archaeological sites, this may be due to poor preservation of organic materials and the inundation of coastal areas mentioned above. We can still infer water travel based on the presence of artifacts made by humans found in island sites.

Other evidence comes from zooarchaeological finds along the Northwest coast. Goat remains as old as 12,000 b.p. have been found on Vancouver Island, British Columbia as well as bear remains dating to 12,500 b.p. in the Prince of Wales Archipelago, British Columbia. Even older remains of black and brown bear, caribou, sea birds, fish, and ringed seal have been dated from a number of caves in Southeast Alaska by paleontologist Timothy Heaton. This means that there were enough land and floral resources to support large land mammals and theoretically, humans. Further intertidal and underwater investigations may produce sites older than 11,000 b.p.. Coastal occupation prior to 13,000 b.p. would allow for people to migrate further south and account for the early South American sites.

Anecdotal evidence comes from the surviving Bella Bella oral tradition as recorded by Franz Boas in 1898. "In the beginning there was nothing but water and ice and a narrow strip of shoreline". Some believe this story describes the Northwest Coast during the last glacial maximum and that the story suggests that the Northwest Coast colonization occurred during the last ice age.

Further south, California's Channel Islands have produced even earlier evidence for seafaring by Paleoindian (or Paleocoastal) peoples. Santa Rosa and San Miguel islands, for instance, have produced five sites dating to the Terminal Pleistocene, including the Arlington Man site dated to ~11,000 radiocarbon years (13,000 cal BP) and Daisy Cave occupied about 10,700 radiocarbon years ago (~11,500 cal BP). Erlandson and his colleagues have also identified several early shell middens located near sources of chert, which was used to make stone tools. These quarry/workshop sites have been dated between about 10,800 and 10,500 RYBP (~12,000–11,500 cal BP) and contain crescents and finely made stemmed projectiles points probably used to hunt birds and sea mammals, respectively. Significantly, the Channel Islands have not been connected to the mainland coast during the Quaternary, so maritime peoples contemporary with the Clovis and Folsom complexes in the interior had to have seaworthy boats to colonize them. The Channel Islands have also produced the earliest fishhooks yet found in the Americas, bone bipoints (gorges) that date between about 10,000 and 9500 cal BP.

Even further south, the Monte Verde site in Chile has become accepted as a settlement around 14,800 years ago.