New Study Suggests Humans Lived In North America 130,000 Years Ago (npr.org)

An anonymous reader writes: In 1992, archaeologists working a highway construction site in San Diego County found the partial skeleton of a mastodon, an elephant-like animal now extinct. Mastodon skeletons aren't so unusual, but there was other strange stuff with it. "The remains were in association with a number of sharply broken rocks and broken bones," says Tom Demere, a paleontologist at the San Diego Natural History Museum. He says the rocks showed clear marks of having been used as hammers and an anvil. And some of the mastodon bones as well as a tooth showed fractures characteristic of being whacked, apparently with those stones. It looked like the work of humans. Yet there were no cut marks on the bones showing that the animal was butchered for meat. Demere thinks these people were after something else. "The suggestion is that this site is strictly for breaking bone," Demere says, "to produce blank material, raw material to make bone tools or to extract marrow." Marrow is a rich source of fatty calories. The scientists knew they'd uncovered something rare. But they didn't realize just how rare for years, until they got a reliable date on how old the bones were by using a uranium-thorium dating technology that didn't exist in the 1990s. The bones were 130,000 years old. That's a jaw-dropping date, as other evidence shows that the earliest humans got to the Americas about 15,000 to 20,000 years ago. The study has been published in the journal Nature.

Comments

Re:Unlikely

[Anonymous Coward]

Don't believe everything you read.

Especially if it is written in a thousands-years-old text of uncertain authorship, and makes important claims about reality without providing evidence.

Re:Unlikely

[RockDoctor]

If you had read the paper (I know, this is a post truth world, so there is never any reason to return to original sources), you'd have read the bit where they say

Initial attempts to date the CM site using radiocarbon analysis at two independent laboratories failed, because the samples lacked sufficient collagen(13). Several attempts to date the site with optically stimulated luminescence indicated that samples were near or beyond the upper limits of dose saturation, and that the depositional age of the sediment is greater than 60â"70 thousand years (kyr) (Supplementary Information 7). Subsequently, multiple bone fragments (Extended Data Fig. 9eâ"g) were analysed by uranium-series disequilibrium methods (Methods and Supplementary Information 8). (Ref 13. Deméré, T. A., Cerutti, R. A. & Majors, C. P. State Route 54 Paleontological Mitigation Program: Final Report (San Diego Natural History Museum, 1995).

There is a heretical idea that people might like to WRITE THINGS down in a PAPER, which reasonable people (your question is perfectly reasonable) might want to know, BEFORE the question is asked. This idea has only been in common use for 350 years, so should be considered provisional, though it has actually proved useful in some cases.

You might care to look at the dates there too. They completed their attempts at carbon dating in 1995, but waited until now to publish this analysis, because without the dating, it isn't particularly interesting. The technique they eventually got a date from (uranium-thorium disequilibrium diffusion-adsorbtion dating) is new enough that I am going to have to, uh, read the fucking paper's dozen pages of Supplementary Information to form a worthwhile opinion on it's validity. Though it is, of course, the obvious point of uncertainty.

There was also some damned fine trowel-work in the original excavation. I take my handlens and knee-pads off to the archaeologist who did that salvage excavation and recording.