May 17, 2013

The human colonization of Australia and Near Melanesia

Continuing with the joint series of articles on the expansion of Homo sapiens, David Sánchez published last week an interesting piece[es] on the original colonization of Australia and Papua at Noticias de Prehistoria - Prehistoria al Día, which I'll try to synthesize here.

Earliest evidences of human occupation of Australia and Near Melanesia (all before 30 Ka BP)

Maybe the most interesting detail is that Lake Mungo 3 has dates that clearly establish a colonization of the continent at least 60,000 years ago:

81.000 +- 21.000 U (Uranium series)
62.000 +- 6.000 ESR/U (Electron spin resonance/Uranium)
61.000 +- 2.000 OSL (Optical Stimulated luminiscence)
40.000 +- 2.000 OSL (Optical Stimulated luminiscence)

The sites of Nauwalbila I and Malakunanja II have provided similar dates: 60-50 Ka BP (OSL) and 61,000 BP +9,000/-13,000 (TL) respectively. So we can safely discard the conservative approach that only allowed for at most 50 Ka as earliest colonization boundary for the Oceanian continental landmass. 

The depiction of a Genyornis, giant duck-like bird extinct before 40 Ka, in Australian rock art ago also supports a very early date for the settlement of Australia. In Highland Papua human presence is also confirmed to at least 49 Ka ago, as I reported in 2010.

Naturally the settlers must have arrived by sea, the most commonly accepted candidate for such a vessel is a humble raft still used by some Papuan populations and which has parallels in Southern Asia (also still in use in some places):


Such a journey was attempted with a similar but larger raft, equipped with a simple sail named Nale Tasih 2. This craft had no trouble in reaching the continental platform of Australia from Timor in just six days and they actually managed to reach the modern Australian coast, although they desisted of beaching by night in the middle of a storm in an area infested by the largest crocodiles on Earth, being evacuated by the coastguard instead (the barge was later recovered in perfect state).

10 comments:

  1. Hi Maju
    I read your article"Homo sapiens expansion in Asia and Australasia from the viewpoint of genetics" with great interest. It would have been great if you had posted the full article in English. The one I read was the Google translation of your original article in Spanish.
    That article led to this post on Australian region which I found to lack references.
    It would be useful to have a reference to original research for the claim "Maybe the most interesting detail is that Lake Mungo 3 has dates that clearly establish a colonization of the continent at least 60,000 years ago:" The reason for having a reference is the following.
    In a letter to the editor of Nature, Bowler et al (2003) claimed:
    "Our study shows that humans were present at Lake Mungo as early as 50–46 kyr ago. We find no evidence to support claims for human occupation or burials near 60 kyr ago. "
    I guess it is good to be little conservative.

    Bowler, James. M. et al (2003) New ages for human occupation and climatic change at Lake Mungo, Australia. Nature 421:837–40. doi:10.1038/nature01383

    DA(at www.thelureofnoma.com)

    ReplyDelete
    Replies
    1. The original (for which this is just a synthesis) is not my article but that of David Sánchez. At the time of writing the above text, the first link was not available (server down?) but the other two were: 60-55 Ka old for Nawalabila I and c. 61,000 for Malakunanja II. One of the key issues is that Genyornis went extinct c. 50 Ka and is unistakably depicted in Australian rock art, what argues strongly for a pre-50 Ka arrival. Also the mtDNA chronology in the area (discussed in a separate article by myself) seems to be quite old, not much later than other Asian lineages and certainly older than West Eurasian ones, what sets a lower boundary: c. 55 Ka BP, when the Western Eurasian colonization began. So I think that 60 Ka BP is a very reasonable minimal age for the settlement of Australasia.

      However it seems correct that the first link is not supportive of the dates explained later, so I will ask David about his actual sources for Lake Mungo 3, which are surely within his extensive bibliography in the original article.

      Delete
  2. Hi Darhi and Maju!! Thanks for your opinion about the post.

    This is the original article published in Journal of Human Evolution.

    This is the abstract:

    “”We have carried out a comprehensive ESR and U-series dating study on the Lake Mungo 3 (LM3) human skeleton. The isotopic Th/U and Pa/U ratios indicate that some minor uranium mobilization may have occurred in the past. Taking such effects into account, the best age estimate for the human skeleton is obtained through the combination of U-series and ESR analyses yielding 62,000±6000 years. This age is in close agreement with OSL age estimates on the sediment into which the skeleton was buried of 61,000±2000 years. Furthermore, we obtained a U-series age of 81,000±21,000 years for the calcitic matrix that was precipitated on the bones after burial. All age results are considerably older than the previously assumed age of LM3 and demonstrate the necessity for directly dating hominid remains. We conclude that the Lake Mungo 3 burial documents the earliest known human presence on the Australian continent. The age implies that people who were skeletally within the range of the present Australian indigenous population colonized the continent during or before oxygen isotope stage 4 (57,000–71,000 years).””


    As I said in the post in Spanish, usually as researchers talk about Australian colonization from conservative point of view.

    We also have the Northern sites in Kadadu National Park, with dating of around 60 ka bp, supporting this early colonization of Australia.

    As Maju said, there are also evidences like the paintings dating from the Genyornis; the Australian megafauna was extinguished between 46,000 and 50,000 years, so that the paintings should be older.

    ReplyDelete
    Replies
    1. Thanks, David. I've changed the relevant link to reflect this study.

      Delete
    2. Hi David and Maju
      This morning I thought I posted a comment which I cannot see here. Anyway, I am rewriting it as this will also add to Terryt's point below. I will write it again. The letter to the editor by James Bowler et al (2003)is more recent than Alan Thorne et al (1999). The latter has been cited in Bowler et al. Thus, I think their conclusions cannot be totally ignored.
      With regard to the megafauna there is no universal agreement. M.J.Morwood, An Australian Rock Art expert, in his book Visions from the past clearly pointed out that "species identification in rock art" is "extremely dubious" and the claims about such depictions "have not been generally accepted". This is a fair point especially when we are talking about long-extinct species.

      Hope this is a point for you to ponder.

      Delete
    3. Hi David and Maju
      This morning I thought I posted a comment which I cannot see here. Anyway, I am rewriting it as this will also add to Terryt's point below. I will write it again. The letter to the editor by James Bowler et al (2003)is more recent than Alan Thorne et al (1999). The latter has been cited in Bowler et al. Thus, I think their conclusions cannot be totally ignored.
      With regard to the megafauna there is no universal agreement. M.J.Morwood, An Australian Rock Art expert, in his book Visions from the past clearly pointed out that "species identification in rock art" is "extremely dubious" and the claims about such depictions "have not been generally accepted". This is a fair point especially when we are talking about long-extinct species.

      Hope this is a point for you to ponder.

      Delete
    4. "This morning I thought I posted a comment which I cannot see here".

      It's not in the spam folder, so I have no idea what happened to it. Sorry.

      Instead Terry's comment has gone to the spam folder because he's explicitly banned from commenting here. Sorry for the inconvenience.

      ...

      ... ""species identification in rock art" is "extremely dubious""...

      If it looks like duck and quacks like a duck...

      Well, we don't know how it quacked, admittedly.

      Whatever they say about Lake Mungo 3, there are still other dates from other sites, already mentioned, all of which point to a colonization c. 60 Ka BP (or earlier).

      Delete
  3. Hello all,

    These are the dates that i mentioned in spanish blog:

    81.000 +- 21.000 U (Uranio)
    62.000 +- 6.000 ESR/U (Electron spin resonance/Uranio)
    61.000 +- 2.000 OSL (Optical Stimulated luminiscence)

    Thorne et al. 1999

    40.000 +- 2.000 OSL (Optical Stimulated luminiscence)

    Bowler 2003.


    For me, although the study is later does not seem conclusive because in the first study Thorne et al. uses three different dating methods, and also in the Bowler study use the same technique OSL, so I dont know wich is the reason to reject the 61 ka bp dates

    From my point of view, the discussing about Lake Mungo 3 started because the old dates refer an area located further south than expected, and this is a recurring argument from conservative point of view, and that somehow affects their interpretation on the age of the remains .

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    Replies
    1. Hi David & Maju
      Given the uncertainties around these dates, you may well be correct. What I am pointing out is that rejecting conservatism out of hand may be a little expedient until there is a better concesus.
      To revisit David's point about the conclusiveness of previous OSL estimates, I can quote the following from Bowler et al (2003). "Optical ages of 59 +/- 3 and 63 +/- 3 kyr were obtained
      for sands collected approximately 300m away from the burial site
      and were then thought to relate to the sediments into which Mungo
      III was inserted. The reliability of these age estimates has been
      contested."

      I agree with Maju. We don't know how the extinct duck quacked. We also don't know what cultural biases people had depicting these animals. We argue these animals had been long extinct and therefore the rock art depicting "them" should be at least 40Kyr (or, say 60Kyr) old. What if the identification is wrong?

      Delete
    2. Can you imagine Darwin bowing to "consensus"? Science cannot advance on "consensus", instead consensus is generated by accumulation of evidence in support of some particular model. Consensus is, if anything, the product not the foundation of science.

      It may be true however that there is some debate on the Mungo 3 dates. However we still have two other reference sites, which support the same scenario of c. 60 Ka (or older) colonization of Australia.

      About Genyornis: "What if the identification is wrong?"

      I don't think there's any possible confusion: the paintings are extremely realistic and there's no other known Australian bird like that one (no, it cannot be an emu).

      Whatever the case it is just another evidence. A single data point may always be debated but when absolutely all data point in the same direction...

      Delete

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