11,000-Year-Old Volcanic Ash Layer Could Rewrite Early Human History in the Americas (Discovermagazine)

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Learn how new research challenges the age of Monte Verde and what it means for early human migration in South America.
Written byStephanie Edwards

Mar 20, 2026, 4:50 PM | 3 min read

A famous archaeological site in southern Chile may not be as old as scientists thought. A study published in Science reexamines decades-old assumptions about Monte Verde, a site that helped overturn the once-dominant “Clovis first” model of human arrival. Now, researchers argue that natural processes may have skewed earlier dates rather than human activity.

The new research suggests the Monte Verde site dates to between 4,200 and 8,200 years ago, rather than 14,500 years ago. If confirmed, the finding could reshape theories about how and when people first migrated into the Americas.
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“There is a lot of ice age wood preserved in stream deposits in the valley. As the stream eroded its banks, that wood accumulated in the channel and on gravel bars,” Surovell explained to Discover. “When we date archaeological sites, there is a recurrent conflict between what we are trying to date (the presence of humans) and what we are actually dating (the formation of wood in this case). Because of the unusual preservation of wood at Monte Verde, there is a massive age discrepancy between those two events.”

In other words, ancient wood — already thousands of years old — may have been incorporated into younger human-made layers, making the site appear far older than it actually is.

Additional evidence strengthens this interpretation. Researchers identified a layer of volcanic ash dated to 11,000 years ago. Crucially, this ash sits below the archaeological materials. If humans had been present 14,500 years ago, the ash would appear above those layers.
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more: https://www.discovermagazine.com/11-000-year-old-volcanic-ash-layer-could-rewrite-early-human-history-in-the-americas-48848

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