North America's first immigrants may have arrived 20,000 years ago, 6,500 years before the Clovis people inhabited the area. This is the conclusion of a study recently published in the journal Science Advances, after a team of anthropologists at Texas State University dated a vast horde of stone tools at a site close to Austin, Texas, to 16,000 to 20,000 years ago.

Up until very recently, the general consensus among anthropologists was that the Clovis people were the first to settle in the Americas, reaching the new land some 13,500 years ago after crossing the Bering Straight. But various new finds (including the butchered remains of a mastodon in Florida) began to poke holes in this theory, and in 2017, the consensus was shattered. It was official: The Clovis people were not the original Americans.

So, if not the Clovis, who were? And how did they get there? The answer to the latter question is almost certainly by boat but, in most other respects, the first Americans are something of a mystery.

Now, a recently discovered treasure trove of ancient stone tools found at the Gault Site roughly 64 kilometers (40 miles) north of Austin might offer up some answers. According to the researchers, the location encompasses a valley between Edwards Plateau and Blackland Prairie that provides reliable springs and high-quality flint stores, which would have made it a welcoming home to the new arrivals. 

As for the stone tools, the researchers selected 200. They were able to work out how old they were using a technique called optically stimulated luminescence age estimates. By monitoring the amount of energy released when the tool is shown light, it is possible to work out when it last received sunlight. Based on this method, the researchers estimated that the tools are between 16,000 and 20,000 years old. This would mean these people predate the Clovis people by at least 2,500 years but possibly more.

It was clearly a popular location, and the researchers also point out there were Clovis artifacts found at the site. These display a distinctive style and look very different fom the older stone tools, and may also be evidence that Clovis technology disseminated across an already established society roughly 13,500 years ago. 

Speaking of the older stone tools, Thomas Williams from the Department of Anthropology at Texas State University said in a statement: "These projectile points are unique. We haven't found anything else like them." 

"Combine that with the ages and the fact that it underlies a Clovis component and the Gault site provides a fantastic opportunity to study the earliest human occupants in the Americas."