海からの視点　最初にアメリカ大陸に到達した人類

カナダのブリティッシュコロンビアのQueen Charlotte Islands(水中）遺跡がアメリカ大陸最初の住人についての研究に新たな一石を投じる可能性があります。

これまではマンモスなどを追ってきた人類がベーリング海峡がつながっていた13000年ほど前に歩いて渡ってきたとされています。しかし、南アメリカ大陸などでは14－16000年前に人類がいた形跡があり(チリのMonte Verdeなど)、それ以前に人類が渡ってきた可能性が強く指摘されています。現在、有力な論はアジア、特に日本周辺から船を使ってアリューシャン列島、そしてアラスカを通り、海岸線を使い南下したと考えられています。アラスカで発見された10000年前の遺骨は日本人、チベット、そして南アメリカの原住民にDNAが類似していたそうです。

カナダ政府や大学が主体となりQueen Charlotte Islandsやバンクーバー周辺を調査したところ、水深５０ｍに当時の地形が残っていたことが確認され、この周辺を発掘する計画が浮上しました。

いままで、人類の歴史を陸からの視点で見てきたが、それを見直す可能性が出てきたと指摘しています。人類の発達において速い段階から海に乗り出し、巧みに船を操ってきたかもしれません。

In a Canadian archeological project that could revolutionize understanding of when and how humans first reached the New World, federal researchers in B.C. have begun probing an underwater site off the Queen Charlotte Islands for traces of a possible prehistoric camp on the shores of an ancient lake long since submerged by the Pacific Ocean.

The landmark investigation, led by Parks Canada scientist Daryl Fedje, is seeking evidence to support a contentious new theory about the peopling of the Americas that is gradually gaining support in scholarly circles. It holds that ancient Asian seafarers, drawn on by food-rich kelp beds ringing the Pacific coasts of present-day Russia, Alaska and British Columbia, began populating this hemisphere thousands of years before the migration of Siberian big-game hunters — who are known to have travelled across the dried up Bering Strait and down an ice-free corridor east of the Rockies as the last glaciers began retreating about 13,000 years ago.

The earlier maritime migrants are thought to have plied the coastal waters of the North Pacific in sealskin boats, moving in small groups over many generations from their traditional homelands in the Japanese islands or elsewhere along Asia’s eastern seaboard.

Interest in the theory — which is profiled in the latest edition of New Scientist magazine by Canadian science writer Heather Pringle — has been stoked by recent DNA studies in the U.S. showing tell-tale links between a 10,000-year-old skeleton found in an Alaskan cave and genetic traits identified in modern Japanese and Tibetan populations, as well as in aboriginal groups along the west coasts of North and South America.

The rise of the “coastal migration” theory has also been spurred by a sprinkling of other ancient archeological finds throughout the Americas — several of them, including the 14,850-year-old Chilean site of Monte Verde, too old to fit the traditional theory of an overland migration by the “first Americans” that didn’t begin for another millennium or two.

Proponents of coastal migration argue that Ice Age migrants in boats might have island-hopped southward along North America’s west coast as early as 16,000 years ago, taking advantage of small refuges of land that had escaped envelopment by glaciers.

The difficulty is that nearly all of the land that might contain traces of human settlement or activity — the critical proof for archeologists — is now under water.

Several significant finds have been made in raised caves along the B.C. coast that were not inundated by the rising Pacific in post-glacial Canada.

In 2003, Simon Fraser University scientists reported the discovery of 16,000-year-old mountain goat bones in a cave near Port Eliza on Vancouver Island, and similar finds of prehistoric bear bones pre-dating the glacial retreat have been held up as proof of a shoreline ecosystem that could have sustained large mammals, as well as human hunters.

The new Parks Canada target is at a site in the Gwaii Haanas National Park Reserve just north of Burnaby Island, near the southern end of the Queen Charlottes.

According to the New Scientist, Fedje has discovered evidence of a prehistoric lake and streambed about 50 metres below the surface at a site called Section Cove, as well as signs that the river and lake were once rich sources of salmon — an “irresistible” food source for ancient coastal migrants.

A book published in 2003 by Canadian author Tom Koppel summarized the research projects being carried out along the Pacific Coast while weaving a powerful argument in favour of coastal migration.

“We have been accustomed to thinking of ourselves as a species in terrestrial terms — evolving in the savanna of Africa; hunkering in caves in Europe; gradually spreading overland through Asia; and finally trekking dry-shod across a land bridge at the Bering Strait into the Americas while preying upon big ice age animals,” he wrote in Lost World — Rewriting Prehistory: How New Science is Tracing America’s Ice Age Mariners.

“But if the scientists on the Pacific coast were right, we also became bold seafarers at a very early date, maritime people who built boats and braved the stormy and icebound shores of the North Pacific.”

引用元：http://www.canada.com/victoriatimescolonist/news/story.html?id=34805893-6a53-46f5-a864-a96d53991051&k=39922