On Sun, 18 Jan 1998 17:28:29 -0600, Glenn Morton wrote:
[...]
>>>GM>75-116 kyr rock engraving Jinmium, Australia a. H. s.58
>SJ>...here is an extract of article in SCIENCE which casts doubts on
>>the Jinmium TL dates. It seems they could be only 10,000 years old,
>>rather than the 116-176,000 claimed!
[...]
GM>Thank you for this. I have ordered the article. I had heard that one guy
>was upsed with the Jinmium dates but had not been able to find confirmation.
>I had e-mailed the fellow three times with no response.
OK. Glad to be of assistance!
GM>However, there is one thing that Jinmium explains that without it is left
>unexplained. The aborigines used fire to kill game. About 140,000 years
>ago oceanic cores and lake cores in and around Australia suddenly started
>showing lots of soot whereas for the 6-700,000 years prior to that, there
>was no soot at all. The argument from these cores has been made that this
>represents the time that humans first occupied Australia. If the Jinmium
>dates hold up, then everything fits together. We know that Homo erectus
>crossed the ocean 700,000 years ago and was on the island of Flores,
>Indonesia. It isn't far from there to Australia (indeed natural forest
>fires on Australia could have been seen from Timor an Island not far from
>Flores.).
Australia is a dry, flat continent. It is often ravaged by
lightning-lit fires in the outback. El-Nino effects can cause a few
years of droughts within otherwise wet periods. Widespread fires in
Australia within an otherwise wet climate could have been a natural
consequence of the beginning of such similar climate patterns. In
fact Australia is experiencing such El-Nino conditions right now. I
saw a fire chief on TV who said the majority of the wildfires in
were caused naturally by lightning.
OTOH I have no problem with Homo erectus being in Australia 700,000
years ago. The issue was whether the Jinmium art was the product of
H. erectus or H. sapiens. If it is 176,000 years old, then either:
a) it was H. erectus (which would make him more intelligent than
previously thought) or b) it was H. sapiens (which would make him
older than previously thought). Since there is no other evidence
elsewhere for either a) or b), and we know about El-Nino caused
fires in Australia, I prefer the latter explanation.
GM>Anyway, I will await the outcome before removing it...If the dates
>fail, you can be assured that I will remove it from my list. I
>have already removed Orce from the copy that went into the book.
OK. But the study casts doubt on *all* the dates obtained by
thermoluminescence:
"If the date falls and there are early signs that Jinmium's real age may
be as little as 10,000 years-it will eliminate a major challenge to the
conventional view of Australian prehistory. But it will also deal a
blow to the credibility of the experimental dating method used at the
site: determining the age of sediments by measuring a tiny
luminescence signal that builds up while the rock or sand grains are
hidden from sunlight. The method is a potential boon to archaeology,
offering a way to put a time scale on sites that can't be dated by any
other method. Indeed, over the past decade, luminescence techniques
have yielded a series of spectacularly early dates, which have put
people in Siberia more than 260,000 years ago, modern humans in
South Africa 260,000 years ago and in Australia 60,000 years ago (at
sites other than Jinmium), and remarkably sophisticated toolmakers in
central Africa 90,000 years ago. But several of these dates are already
in question, and the techniques that produced them are still being
tested and refined. As a result, many archaeologists and
anthropologists are wary of published luminescence dates. "From the
perspective of a consumer, like myself, it can be very difficult to
know in any given instance whether a date is reliable or not,"
complains Stanford University paleoanthropologist Richard Klein.
Such doubts have discouraged many archaeologists, especially in the
United States, from adopting the techniques. While luminescence
dating has proved its value in dating pottery and burnt artifacts,
dating experts agree that it has sometimes been applied too hastily to
ordinary sediments." (Gibbons A., "Doubts Over Spectacular Dates",
Science, Vol. 278, 10 October 1997, p220).
You might consider some such disclaimer in your list?
God bless.
Steve
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Stephen E (Steve) Jones ,--_|\ sejones@ibm.net
3 Hawker Avenue / Oz \ Steve.Jones@health.wa.gov.au
Warwick 6024 ->*_,--\_/ Phone +61 8 9448 7439
Perth, West Australia v "Test everything." (1Thess 5:21)
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