Artifacts Throw Existing Theories For A Loop

The Americas were inhabited by human beings at least as early as 12,500 years ago - far earlier and a half a world farther south than previously believed, a team of archaeologists announced Monday.

Artifacts unearthed at a site near Monte Verde, Chile, the nine-member group determined, predate by at least 1,300 years the evidence of human habitation from Clovis, N.M., conventionally accepted as the oldest to have been discovered in the Western Hemisphere.

More portentous, however, is the fact that the discovery is in South America, thousands of miles away from the Clovis site. That suggests that the first Asian immigrants arrived by a different path from the one traditionally assumed (across what is now the Bering Strait) or got there much earlier than the current scientific consensus allows, or both.

Indeed, the Monte Verde dig also has revealed preliminary evidence that Homo sapiens may have been in residence there as long as 33,000 years ago.

“It totally changes how we think of the prehistory of America,” said Monte Verde team member Dennis J. Stanford of the Smithsonian Institution.

Since 1977, researchers headed by Tom D. Dillehay of the University of Kentucky have been excavating the riverbed site some 500 miles south of Santiago. They discovered remnants of dwellings with wooden frames and animal-hide roofs, tools made of stick and bone, a piece of what is apparently mastodon meat, more than 700 stones tools and a child’s footprint.

The Clovis record has stood since the late 1930s, though numerous contenders for evidence of earlier human habitation have arisen. Until now, none had proved convincing to a majority of scientists.

At a minimum, the new find will oblige scholars to reconsider the standard explanation of what Dillehay called “the first chapter of human history in the Americas.”

The accepted theory is that restless prehistoric peoples from northeastern Asia managed to migrate into Alaska when global cooling trapped ocean water in glaciers, thus lowering the sea level and exposing enough of the Bering Strait sea floor to provide a land bridge.

This hypothesis also requires that there have been an ice-free corridor - formed between two retreating ice masses - that would have allowed the first New World humans to survive a trek southward through the Yukon. Both essential conditions for this climatic “window” existed about 14,000 to 12,000 years ago.

So when scientists first dated the Clovis artifacts (typically stone “points” used to kill mammoths or other animals) to about 11,200 years ago, the chronology seemed ideal. Presumably, the first settlers crossed the land bridge on schedule and their descendants then took about a thousand years to get as far south as New Mexico.

The new findings make this notion far less tenable. If the Monte Verde site is 12,500 years old, that means that the ancestors of those Chilean settlers somehow managed to travel some 10,000 miles from the Bering Strait to southern South America in only a few hundred years.

Climate data and other evidence show that the next earlier window of migratory opportunity existed about 22,000 years ago.