Did Paleoamericans cross the Bering Strait 100,000 years
ago? Image Credit: Adapted from LeFever 2012 (5).
In two previous posts (here and here), I examined the
formation of the Bering Land Bridges. The dates generated for the existence of
these Land Bridges has profound implications for the peopling of the Americas.
1. Homo erectus senso lato around 2Mya.
2. Ancestors of Homo heidelbergensis and/or Homo ergastor
about 0.5Mya.
3. Homo sapiens or their archaic forebears perhaps as early
as 0.15Mya.
Therefore as ALL of these species have been present in East
Asia over hundreds of thousands of years, it seems possible, given the
opportunity presented by the Bering Land Bridges, that any, or all of them
could have crossed from Asia and populated the Americas.
To decide on the who, we kind of need to know the when.
Looking on the web for difficult
to answer questions can be a frustrating business for instance try “What is the
earliest man could have arrived in the Americas”. The top 10 results were
16,300BP (Athena publishing), 14,500BP (Smithsonian), 15,000BP (Wikipedia),
15,500BP (Guardian), 15,000BP (Daily Mail), 13,300BP (PBS Newshour), 14,000BP
(Nature), 12,000BP (National Geographic), 22,000BP (New York Times) and
16,500BP (Centre for the First Americas). The average date is therefore about
15,400BP. This is despite the fact that Dillehay (4) recently published a paper
stating that the Monte Verde site near the southern tip of Chile was occupied
by 18,500BP.
I find this deeply frustrating.
With very little effort one can find NUMEROUS sites that have good evidence
that pre-date these stated dates by a WIDE margin.
Current evidence of man in the Americas can be summarised in
the following table:
If we assume that these dates are correct, could
anatomically modern humans account for these occupations?
To decide whether the full range of occupation dates listed
above, can be accounted for by Anatomically Modern Humans (AMH) we therefore
need some estimate of the rate of Human Migration. I could at this point try to
refer you to a range of estimates from learned papers on the internet, however
these are even more sparse and contradictory than dates for the first peopling
of the Americas as outlined above.
Therefore I have carried out a simple calculation based on
some of the published, dated fossils from along man’s migration route.
Taking the fastest migration rate of 0.27Km/year we can do a
simple calculation about the arrival time at Monte Verde in southern Chile:
Wales Alaska to Monte Verde Chile = ca. 14726km
Migration time 14726/0.27 = 54540 years
Therefore arrival
time in southern Chile would be 94400-54540 = 39860 years BP
Conclusions:
1. Anatomically
modern humans could have arrived in Beringia ca. 100,000 years ago.
2. Given a migration
rate of 0.27Km/year all sites in the Americas, with the exception of Valsequillo
and Calico could have, therefore, potentially been occupied by Anatomically
Modern Humans (AMHs).
3. Arguments
regarding the opening and shutting of the Ice-Free corridor are irrelevant as land-based
migrations could have taken place BEFORE it closed. Coastal migrations are not
ruled out.
4. A quick check against my previous post here shows that Bering Land Bridge 4 96-93 Kya, 5 104-102 Kya and 6 114.5-111.5 Kya existed at approximately the right time for this human migration.
4. A quick check against my previous post here shows that Bering Land Bridge 4 96-93 Kya, 5 104-102 Kya and 6 114.5-111.5 Kya existed at approximately the right time for this human migration.
5. Valsequillo and
Calico, if real sites of human occupation MUST, therefore represent an archaic
human population such as Homo erectus.
References
1. Ian McDougall, Francis H. Brown & John G.
Fleagle.2005. Stratigraphic placement and age of modern humans from Kibish,
Ethiopia. Nature 433, 733-736 doi:10.1038/nature03258
2. R. Grun et al. 2005. U-series and ESR analyses of bones
and teeth relating to the human burials from Skhul. Journal of Human Evolution
49 316-334
3. Wu Liu, et. al. 2015. The earliest unequivocally modern
humans in southern China. Nature 526,
696–699. doi:10.1038/nature15696
4. Dillehay TD, Ocampo C, Saavedra J, Sawakuchi AO, Vega RM,
Pino M, et al. (2015) New Archaeological Evidence for an Early Human Presence
at Monte Verde, Chile. PLoS ONE 10(11): e0141923.
doi:10.1371/journal.pone.0141923
5. Greg LeFever Ancient Tides blog 2012. Retrieved from:
http://ancient-tides.blogspot.co.uk/2012/12/native-american-genetic-source-is.html
Considering what we have debated at my blog these last weeks, I think that your description of the pre-20 Ka findings in the table is extremely biased. Wasn't the Arroyo del Vizcaino site the one of the "cutmarks"? That's not "excellent" evidence but quite dubious by definition.
ReplyDeleteHi Maju, no I believe the authors did an excellent job of explaining why the cut-marks on the giant ground sloth, Lestodon armatus bones at Arroyo de Vizcaino were made by humans 30,000 years ago. I do not believe anyone but yourself has categorised the cut marks as dubious.
ReplyDeleteI tried to detail how Farina et al. had proved the cut marks were made by humans, while discussing the Arroya de Vizcaino site with you on your blog. If you recall I made the following points:
“The Farina et al paper addressed the issues of the taphonomic modification of the bones at Arroyo de Vizcaino in some detail. Firstly they looked at the age profile of the ground sloths. This matched those of other human kill sites. Secondly they sorted the bones into those modified by trampling from those that had putative cut marks. That figure was 5% again comparing well with other well documented human kill sites. Next the authors analyzed whether animal trampling was the cause of the scratches on bones or whether human modification was provable. They used the latest criteria and analysis techniques as laid out in DomÃnguez-Rodrigo et al. 2009 (A new protocol to differentiate trampling marks from butchery cut marks. J. Archaeol. Sci. 36, 2643–2654.) to prove their case. A quote that paper: "Here we present a multivariate analysis of more than a dozen variables and show that butchery and trampling marks have very distinctive microscopic morphology." Hence I believe they showed conclusively that some of the bones were modified by humans. They also found lithic implements in the bone bed. Overall the authors seem to have been very thorough in discounting any cause other than human modification to the cut marks on the bones. Therefore it seems likely humans entered the Americas some time between ca. 75,000 and ca. 33,000 years ago depending on which migration rate one uses.”
My blog does usually ‘pass judgement’ on an authors’ findings from their papers, HOWEVER, all I seek to do is bring to some lesser known sites and issues to a wider audience.
With respect to the table with dates ranging from 17500BP (Buttermilk Creek) to 200,000BP (Calico), I have covered some of them on this blog and intend to cover the rest of them in time. For each site (that I have covered so far) I look at the evidence the professional archaeologists presented in papers and pull out the details to show how they constructed their arguments. I did so to show that there are a wider range of opinions about the timing of the peopling of the Americas than current opinion allows for. The consensus about the timing of the peopling of the Americas has slowly moved from ca. 13500 years ago to around 20000 y.a. at present. I therefore do not believe my presentation is biased it just represents a different point of view than yours.
With regard to the Farina paper the fact that it has not been widely attacked for the quality of its science by professionals noted for their expertise in taphonomy, should perhaps have given you pause before you called their evidence ‘dubious’?
If you could provide me some references on which you base this opinion of yours about Farina’s ‘dubious’ categorisation of the cur marks as human made, or explain your own experience/qualifications in taphonomy, I would be only too willing to publish your comments.