The settlement of the Americas has always been a controversial topic in archaeology. Conventional wisdom has been that the first humans in North America (the Clovis people) arrived via the Beringia Land Bridge near the end of the glacial period, then moved down an ice-free corridor to reach the bulk of North America, and from there to South America. I've doubted this theory for years, ever since reading about Tom Dillehay's excavations at Monte Verde in Chile.
This week a BBC report details recent evidence that a [spear] "point" found in a mastodon bone has been reliably dated to 13,800 years before the present.
This places it before the so-called Clovis hunters, who many academics had argued were the North American continent's original inhabitants...I am also gobsmacked to read that it is now possible to date specific amino acids (!). You learn something every day.
A succession of archaeological finds right across the United States and northern Mexico have indicated there was human activity much earlier than this - perhaps as early as 15-16,000 years ago. The mastodon rib, however, really leaves the once cherished model with nowhere to go...
These investigations included new radio carbon tests using atomic accelerators. "The beauty of atomic accelerators is that you can date very small samples and also very chemically pure samples," Prof Waters told BBC News. "We extracted specific amino acids from the collagen in the bone and dated those, and yielded dates 13,800 years ago, plus or minus 20 years. That's very precise."
DNA investigation also threw up a remarkable irony - the point itself was made from mastodon bone, proving that the people who fashioned it were systematically hunting or scavenging animal bones to make their tools...
When Clovis-First was first proposed, it was a very elegant model but it's time to move on, and most of the archaeological community is doing just that."