For the Americas overall, the earliest known are from Blusfish Caves in the Yukon at about 24,000 years ago. The next oldest are from Monte Verde in Chile at some 18,000 years ago.
Meadowcroft Rockshelter near Pittsburgh is likely pre-Monte Verde though the debate is still out. The most popular current thought is that it’s 19000 Before Present, beating Monte Verde by 1000 years although a minority of archaeologists say it was only 16000 BP. It has distinct pre-Clovis artifacts like Miller points.
BTW, Bluefish Caves don’t have the oldest artifacts. Their artifacts only date to about 12000. What they have is animal bones with nicks on them that date to 25000 BP. The early date claimers say the nicks were caused by butchering tools, but it’s a controversial claim with no consensus and most archaeologists think the nicks were made by falls and scavengers. Most ‘early date’ theorists put the earliest arrival date in the Americas at 22000, so the 25000 really changes things. I’d say it’s unlikely to be true.
Well, as the OP can tell, there’s no outright consensus on this question among experts. Some of that is normal disputes but the Clovis First hypothesis, which dominated American archaeology for years, is to blame for most of it. Every site that dated to earlier than 13,000 years ago was severely questioned and put to a very high standard of evidence and then universally rejected by the Clovis First advocates.
Anyway, the Bluefish Caves are in Beringia, the region now composed of Alaska, the Bering Strait, far eastern Siberia and some of Yukon/NWT. Because it was mostly ice free during the last Ice Age, it was thought to have been inhabited much earlier than the rest of the Americas. But there were glaciers to its southeast which prevented further overland migration. The people there eventually either developed boats to do the coastal migration thing (my guess) or the ice free corridor on the east side of the Rockies opened up and they migrated that way. Of course, that still leaves the question of when people first got to Beringia.
There were migrations from 13k-10K BP from that Beringian standstilll population in both directions, but where the earlier populations came from is unsolved as you noted.
While the post-contact deaths and genocide make it hard to do full DNA studies, I would guess as boats especially with Australia being inhabited over 40,000 BP and Ust’-Ishim is reasonably close to modern East Asians, Papuans, and Native Americans but not as close to Baltic populations. Unfortunately and fortunately Ust’-Ishim’s DNA has far better coverage than most ancient samples and simplistic tools often cause issues in studies I have seen.
But like most areas of paleogenetics, the common claim in archaeology of *founding *populations seems to be *replacing *populations.
While still pre-print and preliminary, this paper just dropped and will show how complicated this is.
But it will not solve the debate or question about the initial peopling of the Americas however it was not the land bridge.
I assume you mean “not the Ice-Free Corridor.” The first inhabitants of the Americas certainly came through Beringia at some point. It’s how and when they got farther south that’s been the question.
There is no evidence of people in Beringia between 25,000 and 14,000 years ago when the isolation happened. The two major clades of Native Americans differentiate from one another after that time, but it is only a “theory” that they were in Beringia.
Travel through Beringia is generally considered as not possible by land until after the Americas were peopled by the *Southern *clade. But we do know that Xach’itee’aanenh t’eede gaay was the Nothern clade in that area. With the rate of advancement and other factors like Australia as an example it may be that they floated along the coast or were living on marine mammals etc…
Without evidence one can’t simply claim that they walked across the glaciers earlier and there is zero evidence so far of humans in Beringia at the time when the two clades split.
The old theory of how the Americas were originally settled by hunters following megafauna across the ice-free land bridge is pretty much debunked and the boat theory seems more likely today.
By boat along the coast of what? Unless you are postulating that they sailed straight across the Pacific then they moved along the coast of Beringia, regardless of whether they were living much inland.
Yes, I agree that the consensus these days is that the first inhabitants of the Americas south of Alaska probably came along the coast by boat, at least around places where the land route was blocked by glaciers. But they still would have used the Bering Land Bridge for part of it, even if it was just along the coast.
As far as know, there was no significant obstacle between that region and Alaska during the time in question. So why couldn’t these northeastern Siberians migrate to Beringia?
The timing of the opening and the habitability of the Ice-Free Corridor have been questioned since the early 1980s at least. The finding that it was still at least partially blocked until 11,500 years ago, plus the confirmation of the age of Monteverde in Chile, was what helped disprove that Clovis peoples might have used this route to colonize North America. (Ironically, it seems now that the corridor may have been a route for Clovis people to have moved north from the Great Plains into Canada.)
The “theory” is that Beringia was isolated, and you have major admixture events, look at the other cite, which is peer reviewed at least. There is some evidence that the group was from the Lake Baikal area, not Beringia.
There is also the “possible more modern” DNA link between Amazonians and Australasians that shows that at least some sea travel was possible.
Calvert and Triquet Island in BC show some coastal presence and Cedros Island in Mexico shows highly developed coastal skills that, while those sites are not, the methods almost certainly predated the clovis technology by a significant amount of time.
Archaeologists are challenged by bias introduced during analysis and underestimate the flexibility of early modern humans. The story is probably going to be way more complex once we discover enough evidence.
The “Clovis First hypothesis” land bridge idea was partly based on the idea that the Clovis technology came from Asia where it now seems that it was invented in the Americas.
Today we just don’t know if “Clovis” was a population migration or just the spread of a technology.
But what we do know is that the first peoples didn’t follow megafauna across a land bridge to get here. That idea is still popular but was based in cultural biases and didn’t have real evidence that Clovis technology came from Asia.
I am always highly skeptical of claims that radically push back human occupation of the America’s, but this was publisbed in Nature, so it’s not crackpot.