40,000-yr-old footprints in Mexico

[Bluegill]

CNN article on old prints

I hadn't seen this discussed here.

LONDON, England (AP) -- British scientists claimed on Tuesday to have unearthed 40,000-year-old human footprints in central Mexico, challenging previous studies that put the arrival of the first humans in the Americas at about 13,500 years ago.

Scientists Silvia Gonzalez, from Liverpool John Moores University, and Matthew Bennett, of Bournemouth University, found the footprints in an abandoned quarry close to the Cerro Toluquilla volcano in the Valsequillo Basin, near Puebla, south of Mexico City in 2003.

Yet another bit of evidence that humans have been in the Americas much longer than previously thought.

How widely accepted is it now that humans have been here quite a bit longer than 13,000 years?

Interesting stuff.

 

[CBL4]

How widely accepted is it now that humans have been here quite a bit longer than 13,000 years?

Lots of alleged sites but none have the strength to upset the Clovis idea. I have read studies that use language, DNA, etc to put the date much older but then their are studies which disagree.

Jared Diamond in "Guns, Germs and Steel" seems to think that the 13,000-15,000 year date is the most probable. Since he seems knowledgable and has no axe to grind, I would tend to agree with him. I do not remember his arguments but they were convincing to me at the time even though I believed an older date.

Here is a synopsis of a 2003 DNA study.

Scientists studying the genetic signatures of Siberians and American Indians have found evidence that the first human migrations to the New World from Siberia probably occurred no earlier than 18,000 years ago. ... They estimate that the DNA change, called M242, occurred 15,000 to 18,000 years ago, meaning the Americas must first have been occupied after that date.
...
Hitherto some archaeologists have argued that people reached the Americas as long as 30,000 years ago. This date received some genetical support last year in a study by Dr. Douglas Wallace, now of the University of California at Irvine, who matched up male migrations from Siberia with the female migrations that he and colleagues had worked out earlier. The female migrations are traced by analyzing a genetic element in every cell called mitochondrial DNA.

Based on the mitochondrial DNA of the women descended from those in the first migration, Dr. Wallace estimated it occurred 20,000 to 30,000 years ago. Dr. Spencer said in an e-mail message that mitochondrial DNA was hard to date accurately and often gave dates that were too old. The Y chromosome is a better genetic clock, if a suitable marker can be found, he said.

http://www.neara.org/MiscReports/07-25-03.htm

Here is the 13,000 year old linguistic view:

According to Greenberg's comprehensive analysis and classifications of the aboriginal languages, a model proposing historical inferences concerning the settlement of the New World was proposed: There were three prehistoric migrations of peoples from Siberia or at least three migrations that left linguistic traces.
...
The wide range of dates for the Eskimo-Aleut divergence tended to cluster about 4,000 BP. In regards to Na-Dene, Swadesh (1959) arrived at 9,000 BP as the date of Proto-Na-Dene by comparing Haida with the other languages in the group. Other glottochronological dates for Na-Dene are estimated around 4,700 to 5,000 BP because of the disputed relation of Haida to the other Na-Dene languages. Greenberg asserts his belief that the earlier, 9,000 BP date is likely more probable. As for the Amerind language family, Greenberg's calculations date the divergence to older than 11,000 BP, a time period suggested beyond the limits of glottochronology (Greenberg et al. 1986).

Here is the older view:

Although the linguistic models proposed by Nichols (1990) and Rogers (1985) do not indicate absolute dates for the settlement of aboriginal peoples in the Americas, the evidence from both of these studies clearly indicates the presence of cultural groups long before the conventional beliefs. Both these linguistic models lend support to the archaeological evidence of human occupation in South America at 40,000 years BP, and agree with the geographic distribution and diversity of aboriginal language groups throughout the Americas.

http://www.ualberta.ca/~nativest/pim/zazula.html

CBL

 

[espritch]

If that turns out to be true, it's going to require a serious rewrite of early human history in the New World. Still, I can't help but wonder why no artifacts have been found anywhere near that old.

 

[Dagny]

I don't know much about this specific subject, but it's similar to the disagreements between molecular geneticists and paleontologists. I guess it really comes down to which methodology you find more persuasive: "molecular clocks" or or the variety of dating methods used with fossils. All I really know about molecular clocks is that it's based on the idea that mutations happen at a steady rate, so any divergence can be given a time line. From what I gather it’s controversial, but generally accepted. I’ve never been all that impressed with the assumption, personally.

But I could be biased just because I know more about the dating methods used with fossils, and I find them quite convincing.

 

[Dagny]

If that turns out to be true, it's going to require a serious rewrite of early human history in the New World. Still, I can't help but wonder why no artifacts have been found anywhere near that old.

There are all sorts of reasons:
1) Preservation requires specific conditions (especially for trace fossils like footprints).
2) No one has found them yet. There's always a first time.
3) The older the specimen, the less likely it is to have survived erosion and other such damage.
4) The dating isn't accurate.

(I'm assuming that rules in paleo apply to archeology)

 

[CBL4]

If that turns out to be true, it's going to require a serious rewrite of early human history in the New World. Still, I can't help but wonder why no artifacts have been found anywhere near that old.

The skeptic phrase "Extraordinary claims require extraordinary evidence" holds true here. This is too unexpected and unconvincing to change the current viewpoint. This is not to say it untrue but, for now, the vast majority of evidence points to later inhabitation.

CBL