Seaweed's age points to ancient habitation

Seaweed found at an inland settlement in Chile confirms it is one of the oldest inhabited sites in the Americas and demonstrates that the villagers had extensive contact with a coastline that was 50 miles away, researchers said Friday.

Radiocarbon dating of the seaweed samples shows that they are 13,980 to 14,220 years old, confirming that the site, Monte Verde, is at least a millennium older than the Clovis sites in the U.S. Southwest, long believed to be the most ancient in the New World.

The report comes a month after researchers reported similar dates for fossilized human feces, called coprolites, found in Paisley Cave in Oregon.

Together, the reports support the growing idea that the first immigrants to the Americas arrived from Asia over a land bridge across what is now the Bering Strait and made their way down the Pacific Coast as far as South America, exploiting abundant marine resources as they traveled.

Most archaeological evidence of such a migratory path is presumed to have been destroyed because sea levels have risen nearly 200 feet since then. Researchers thus have had to find indirect evidence to support their arguments.

Monte Verde, in what is now a peat bog about 500 miles south of Santiago and 10 miles from the coast, was a small village of about a dozen huts on a minor creek.

About 20 to 30 people probably lived there, said archaeologist Tom Dillehay of Vanderbilt University in Tennessee, who has been studying the site for 30 years.

The seaweed samples were found throughout the site, Dillehay and his colleagues reported in the journal Science.