Skip to comments.Anatolian tree-ring studies are untrustworthy
Posted on 02/03/2006 8:59:13 AM PST by SunkenCiv
The approach that was adopted for Anatolia, however, was to rely largely on what is called a "D-score". The D-score does not exist in statistics. It has been used solely with tree rings. D-scores do not have a mathematical derivation -- unlike t-scores, g-scores, and times series. In fact, D-scores were more or less just made up (in an unpublished 1987 thesis), and using them to evaluate a tree-ring match turns out to be little better than rolling dice... The most important of those dates was perhaps for wood from a shipwreck, which was claimed to resolve some of the debate about dates... In 1998, some details on the shipwreck wood were published... In 1999, a letter was sent to various e-mail lists, and also to the principal investigator in Anatolian tree-ring studies, pointing out some of the above (especially the statistical aspects) and concluding that there was no tree-ring match for the shipwreck wood. Two years later, in the next major paper in Anatolian tree-ring studies, the tree-ring date for the shipwreck was acknowledged to be "not especially strong"... The shipwreck and the gateway are from two of many archaeological sites that are claimed to have been dated in Anatolian tree-ring studies. How bad are the others? The others have not been published in sufficient detail to be sure; indeed most have not been published at all -- the dates have simply been announced. That is, the shipwreck and the gateway were not chosen becaujse they are especially strong examples of bad practice, but because they are the two sites that have been published in greatest detail. There is only one other site that has been published in some detail.
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I wrote a paper on dendrochronolgy back in 1975 for one of my archeology courses. Very interesting topic. I don't share Mr. Keenan's lack of confidence in D-scores, though. I think it can become a useful statistical tool in this field.
If I understand dendrochronology, they are compiling--actual samples--a time schedule that will eventually be continuous all the way back, but that will vary from one region to another because climate varies from one region to another. Anatolia might have had a few good growing years while Attica was bone dry, for example, so samples could not in general be directly compared.
IIRC, that is the weakness of dendrochronology. If you do not have a means of connecting tree rings regionally, then you lose the continuum. The statistical confidence level drops and you can't piece together a reliable timeline.
That is what I was thinking. The collection for the Upper Adriatic would have to be separate from that for Tunisia. There would be gaps in each collection, and making the various collections would involve a lot of serious fieldwork. Not a small project.
Yes, regional differences do occur however, they are still useful for determining worldwide events.
"Dr Mike Baillie, Professor of Palaeoecology in the School of Archaeology and Palaeoecology at Queen's University, Belfast, Northern Ireland, is a leading expert in dendrology, or dating by means of tree-rings. In the 1980s, he was instrumental in building a year-by-year chronology of tree-ring growth reaching 7,400 years into the past."
I've read that the tree-ring records have been extended back to 10k years now.
I have also heard that there is a continuous record of sorts.
Absolutely amazing stuff. The creativity and inventiveness of human scholarly efforts never ceases to astound.
Pinging the expert.
Pinging the expert.
The tree-ring records I am familiar with are from southern California (the White Mountains) and Arizona. Didn't even know where Anatolia was until I looked it up.
The latest I have heard on the calibration:
Dendrochronologically dated tree-ring samples cover the period from 0-12.4 ka cal BP. Beyond the end of the tree-rings, data from marine records (corals and foraminifera) are converted to the atmospheric equivalent with a site-specific marine reservoir correction to provide terrestrial calibration from 12.4-26.0 ka cal BP. Source
Hope this helps.
You Turkey! :)
So will this change the dates we normally see in textbooks for the Hittite and Phrygian civilizations? It sounds like the type of discovery Immanuel Velikovsky would have liked to see.
One trouble is that (for an example from the paper) two trees growing on the same hillside but different elevations generally have quite different and unmatchable tree ring sequences, even when they are contemporaneous. There are also problems with soils, such that volcanic soils are enriched in C12, leading to plants showing false antiquity.
And without the bark, there's not even a clue about how much later the tree was cut down to make the gate. :')Do the results from the developing dendrochronology for Anatolia agree or disagree with CoD?Only the results from one Hittite site have been formally published, those from Tille Höyük on the Euphrates. These were striking. The construction of the last phase of the Tille Höyük Gateway is dated to 1101 + 1 BC, with its use lying in the 11th century BC. Yet Tille Höyük was an Imperial Hittite outpost, which on the conventional chronology would have been constructed about 1300 BC, and destroyed c. 1190 BC. The dendro-date is clearly impossible for the conventional chronology. Furthermore, the best fit for this sample (using the normal T-score statistical test) is actually in 942 + 1 BC (James et al. 1998, 41, n. 10)! An extra statistical test had to be introduced to avoid this awkward conclusion.
Peter James et al
So far, so good. Over at the New Chronology Group, we have recently come to the conclusion that the Hittite Empire ended in the reign of Egypt's Merneptah, whenever that took place, and the latest date I saw proposed for Merneptah is 885-865 B.C., less than 80 years after the 942 date you mentioned.
More like 575-564. :')
Probably so. I find the tree-ring patterns in the spruce I cut from my own yard to be hard to match when the trees are only a few yards apart.
I saw that.
A date of 1305 BC for the Late Bronze Age shipwreck of Uluburun was trumpeted as confirmation of the generally accepted chronology... In the recent Science paper it was virtually retracted... Another date of 1621 BC for a wooden bowl from the Shaft Graves at Mycenae has been categorically withdrawn. -- Peter James, "The Dendrochronology Debate", Minerva, v13 n4 (July/August 2002), p. 18
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