Reading The dispute over the colonization of the continent. Scientific jealousies or sloppy work? Archeological finds in South America are not recognized by US researchers - they are decidedly older than the North American ones. They came from Asia, and they came over land: the first people in America. On their way from Siberia to Alaska, small groups of hunters roamed a landscape that resembled the tundra of Northeast Asia. Beringia call the primeval researchers this now defunct country. Where today the water of the Behring Strait divides Asia and America, dry land stretched until the end of the last ice age 15, 000 years ago: the sea level was more than 90 meters lower than today. For much of the water of the seas was bound in the continental glaciers.

When the first humans came and what path they took to colonize the two continents - this gives rise to scientific argument. Because: Hardly arrived on the American side of the land bridge, faced the immigrants huge glaciers. The representatives of the "land hypothesis" designed a gigantic scenario for overcoming these ice masses: Long periods of relative warming melted corridors into the glaciers, the climate in the passages was passable, the hunters found food. So far, however, archaeological finds that support this idea are missing.

The representatives of the "sea hypothesis" claim: The primitive people built boats and drove along the coasts to the south. The colonization of the interior was not a problem. The Hamburg prehistorian Prof. Hans Ziegert is convinced: "The population pressure along the coast was large enough that people have also wandered over the Rocky Mountains." But so far there is also no sufficient evidence for the permanent settlement of the coasts.

The North American finds, long considered to be the oldest settlement records, are between 11000 and 13000 years old. Stone spearheads and remains of game animals - especially from the village of Clovis in the US state of New Mexico - can be clearly dated with the radiocarbon method. display

The South American finds seem to be much older: In the Brazilian Pedra Furada, the archeologist Niède Guidon discovered fossil hearths and stone tools, which she estimates to be at least 40000 years old. In central Chile near Monte Verde, the American archaeologist Tom Dillehay has exposed several settlements - the oldest he estimated at 33, 000 years.

Both researchers have been fighting for years for the recognition of their finds - and their age. Your problem: The radiocarbon method can not be confirmed so unequivocal old findings. Many US researchers reject the dating of their colleagues in South America.

But the doubts do not seem to be only scientifically motivated. Prof. Ziegert: "The Americans are always inventing new criteria for age determination and then cling to it." Doubt not scientifically motivated?

Some finds in North America have recently given a new picture: In Meadowcroft in the US state of Pennsylvania stone blades were found, which is estimated at an age of 19, 000 years. North America would have been settled much earlier. Nevertheless, the South American findings remain controversial. For many scientists from South America and Europe, however, they are convincing. Prof. Ziegert: "There is no reason to doubt the dates." On one point, however, everyone agrees: The primitive people have quickly settled both parts of the American Koninents: The oldest, generally recognized finds in South America are 11000 years old.

Swantje Middeldorf

© science.de

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